AU2021466603B2

AU2021466603B2 - A hydrocyclone and mining system

Info

Publication number: AU2021466603B2
Application number: AU2021466603A
Authority: AU
Inventors: Dingwu Feng; Mingzhao HE; Yang Yu; Yang Zhang; Changying ZHAO
Original assignee: Sino Iron Holdings Pty Ltd
Current assignee: Sino Iron Holdings Pty Ltd
Priority date: 2021-09-30
Filing date: 2021-09-30
Publication date: 2025-09-11
Anticipated expiration: 2041-09-30
Also published as: WO2023049951A1; AU2021466603A1

Abstract

A hydrocyclone comprising: a body having a chamber; an inlet in communication with the chamber, the inlet configured to receive a processed material from a grinding apparatus; a first outlet associated with the chamber, the first outlet configured to return a first stream to the grinding apparatus; and a second outlet associated with the chamber, the second outlet configured to convey a second stream from the hydrocyclone, wherein at least part of a surface forming the chamber is substantially flat to cause a directional change in the processed material present in the chamber.

Description

A HYDROCYCLONE AND MINING SYSTEM FIELD

[0001] This disclosure relates to a hydrocyclone that forms part of a mineral

processing system. In particular, the invention relates, but is not limited, to a mining system

including a flat bottom hydrocyclone. This disclosure also relates to a method for

incorporating a flat bottom hydrocyclone into a primary grinding circuit for use in the mineral

processing industry.

BACKGROUND

[0002] After iron ore is removed from a mine, there are a number of steps involved in

processing the extracted ore. These steps may include screening the ore to separate fine

particles and then crushing, grinding and separating the iron ore and other valuable metals

or minerals out from the remaining waste materials, known as gangue. The process of

reducing the ore in size and separating the valuable components from the undesired

materials is known as ore beneficiation.

[0003] Grinding is normally a subsequent step after an ore crushing process, and is an

important part of the preparation work for mineral sorting. Grinding has two main purposes:

to break open the ore rock crystals so that the minerals inside can be accessed (and then

separated from the mixture); and to produce mineral filler, which is fine inert mineral matter.

[0004] Primary grinding is the first stage of the grinding process and involves two main

instruments, a grinding apparatus and a classifier. The grinding apparatus grinds feed

material material to to aa smaller smaller size, size, and and the the classifier classifier divides divides the the ground ground products products into into desired desired and and

undesired products. From here, the undesired material is returned to a grinder mill for

re-grinding. re-grinding.

[0005] The grinding process accounts for approximately 45-55% of the energy

consumption for a plant associated with the beneficiation process. This becomes an

increasing, non-obvious problem in processing ores, particularly magnetite, that have lower

ore grade (generally 25-40% Fe) due to the presence of impurities. Further processing is

therefore required to reject the impurities in magnetite ores, making it costly to produce a

commercially suitable concentrate for steel smelters.

[0006] The energy used in grinding is considerably influenced by the efficiency of the

classification operation. Therefore, increasing the classification efficiency is crucial to

2 --

optimising the operational costs of the grinding process and subsequently, the whole plant.

Increasing the classification efficiency can also mitigate overgrinding and the generation of

slime, which can lead to loss of valuable minerals and, in large quantities, cause

degradation of downstream equipment. In addition, the increase of classification efficiency

helps to decrease the circulating load and consequently increase the milling throughput.

[0007] In conventional and small-scale processing plants, spiral classifiers are often

used. A spiral classifier is an efficient classification apparatus, requiring less power and

lower maintenance costs. However, owing to the smaller capacity but larger layout required

of spiral classifiers, they have been widely displaced over the past few decades by

hydrocyclones.

[0008] Hydrocyclones are used to separate components from a flowing mixture. Each

of the components can take the form of a solid, liquid or gas. The separation typically

involves isolating a heavier matter from a liquid. However, the process can include the

separation of two components of the same state of matter. For example, two liquids can be

separated from a mixture, based on the relative densities of each of the liquids. Solids can

be separated out through size or particle density.

[0009] In the mining industry, hydrocyclones have been used to separate components

from a feed or run-off material. Typically, hydrocyclones are used to separate desirable

materials from a run-off slurry and are a commonly used classification apparatus in a

mineral grinding process. Conventional hydrocyclones have a separation chamber, an

input pathway for the feed material into the chamber, and two output pathways for the

different components. The shape of a conventional hydrocyclone is a cylinder positioned

above and in communication with a conical section.

[0010]

[0010] Hydrocyclones use the fluid pressure of the flowing mixture to generate

centrifugal force and cause a number of vortexes to form in the chamber. These vortexes

move the heavier material to the edge of the chamber and then down to the bottom of the

chamber. Typically, there is an outlet positioned in the lower half of the hydrocyclone where

this matter can be discharged. Conversely, the lighter material is pushed towards the top of

the chamber and typically exits through an outlet found there.

[0011] The success of a process using a hydrocyclone for separation may be

attributed to the design of the hydrocyclone, the shape and weight of the materials to be

separated and the process parameters, including the speed and pressure of the feed eed

material.

[0012] A conventional hydrocyclone, with a cylindrical section and conical section, is

the most common type integrated into mineral processing as it is believed to be the most

suitable separator. For example, in a Semi-autogenous (SAG) mill or ball mill grinding

circuit, the cut size is often at around 37-75um, 37-75pm, hence a conventional hydrocyclone is

capable of handling the classification process required. Furthermore, a conventional

hydrocyclone provides a fine material which is, typically, beneficial and desirable.

[0013] However, for an Autogenous (AG) mill circuit (for instance), it is not commonly

appreciated that the cut size often increases to 106-150um, 106-150pm, and sometimes even higher.

This higher cut size can affect what is referred to as the separation or cut point of the

hydrocyclone. The cut point is the size of particle which would be subjected to an equal

amount of centrifugal force and drag force, and the point in which the particle has a 50%

chance of exiting the hydrocyclone through the overflow or underflow. When a conventional

hydrocyclone is employed in this type of circuit, it can lead to a number of non-obvious

problems.

[0014] For example, if more fine material is misplaced to a cyclone underflow, this can

lead to an increase of circulating load and the possibility of overgrinding. This can in turn

lead to restriction of the milling throughput due to a high charging load in the mill caused by

high circulating load. Roping, and other associated problems, frequently occur due to high

feed density caused by high circulating load as well, resulting in coarse particles being

conveyed to further downstream. Roping is an operational issue where an abundance of

solid materials is discharged from the hydrocyclone overflow causing the air core of the

spiral shape of the centrifugal force to collapse and the underflow discharge to resemble a

rope. This can lead to damage of the downstream equipment and, in some situations, can

cause a widespread breakdown across the whole production line.

[0015] Bearing this in mind, the present inventor(s) have developed an improved

system and method with higher efficiency and higher cut accuracy for primary grinding

circuit.

[0016] Any reference to or discussion of any document, act or item of knowledge in this

specification is included solely for the purpose of providing a context for the present

invention. It is not suggested or represented that any of these matters or any combination

thereof formed at the priority date part of the common general knowledge, or was known to

be relevant to an attempt to solve any problem with which this specification is concerned.

SUMMARY

[0017] In one form, a hydrocyclone is disclosed, the hydrocyclone comprising: a body having a chamber, wherein the body includes one or more separate 07 Aug 2025 sections, and wherein the one or more sections are configured to be interchanged to obtain a selected particle size; an inlet in communication with the chamber, the inlet configured to receive a processed material from a grinding apparatus; a first outlet associated with the chamber, the first outlet configured to return a first stream to the grinding apparatus; and 2021466603 a second outlet associated with the chamber, the second outlet configured to convey a second stream from the hydrocyclone, wherein at least part of a surface forming the chamber is substantially flat to cause a directional change in the processed material present in the chamber.

[0018] In an embodiment, the processed material includes magnetite ore.

[0019] In an embodiment, the surface is approximately located at the bottom of the chamber.

[0020] In an embodiment, the surface is substantially flat to improve the classification efficiency in the mineral processing system.

[0021] In an embodiment, the classification efficiency is above approximately 40%.

[0022] In an embodiment, the classification efficiency is above approximately 50%.

[0023] In an embodiment, the classification efficiency is above approximately 60%.

[0024] In an embodiment, the particle size associated with the classification efficiency is approximately 106 μm.

[0025] In an embodiment, the hydrocyclone is configured to process up to approximately 750 to 900 cubic metres per hour.

[0026] In an embodiment, the surface is orientated transversely to one or more further walls of the chamber.

[0027] In an embodiment, the surface is orientated perpendicular to the one or more further walls of the chamber.

[0028] In an embodiment, the directional change includes a substantially perpendicular directional change.

[0029] In an embodiment, the directional change includes two substantially perpendicular directional changes.

[0030]

[0030] In an embodiment, the hydrocyclone produces a separation due to the

directional change of the material against the surface of the chamber whereby: i) particles

above approximately 300um 300µm are generally directed towards the first outlet; and ii) particles

below approximately 300um 300µm are generally directed to the second outlet.

[0031] In an embodiment, particles above approximately 0um Oum to below approximately

200um 200µm are generally directed to the second outlet.

[0032] In In an an embodiment, embodiment, particles particles above above approximately approximately 0um Oµm to to below below approximately approximately

150um 150µm are generally directed to the second outlet.

[0033] In an embodiment, the surface is orientated perpendicular to the one or more

further walls of the chamber.

[0034] In an embodiment, the directional change includes a substantially

perpendicular directional change.

[0035] In an embodiment, the directional change includes two substantially

perpendicular directional changes.

[0036] In an embodiment, the body includes one or more (separate) sections.

[0037] In an embodiment, the one or more sections are arranged to form a column. In

an embodiment, the one or more sections are stacked on top of one another to form the

column.

[0038] In an embodiment, the one or more sections are wider than they are longer. In

an embodiment, width of the one or more sections is defined transversely to a longitudinal

axis of the one or more hydrocyclones.

[0039] In an embodiment, the one or more sections are sealed against each other.

[0040] In an embodiment, the one or more sections include at least two sections that

are different sizes.

[0041] In an embodiment, the one or more sections includes a first section and a

second section that are longer than a third section. In an embodiment, length is defined in

a longitudinal direction along the hydrocyclone. In an embodiment, the longitudinal direction

extends in a vertical direction.

[0042] In an embodiment, the first section and the second section are of the same

length.

[0043] In an embodiment, the first section is longer than the second section.

[0044] In an embodiment, the one or more sections are configured to be interchanged 07 Aug 2025

to obtain a selected particle size.

[0045] In an embodiment, the first outlet is located in the lower portion of the chamber. In an embodiment, the first outlet is located in the surface of the chamber.

[0046] In an embodiment, a spigot or apex is located in the lower portion of the chamber. In an embodiment, the spigot or apex is located in the first outlet. In an embodiment, the spigot is located in the side wall of the first outlet. 2021466603

[0047] In an embodiment, silicon carbide is applied to the surface. In an embodiment, silicon carbide is applied to the spigot.

[0048] In an embodiment, the density of the processed material varies from 30% to 60% solid material.

[0049] In an embodiment, the working pressure of the processed material is between 40kPa and 90kPa.

[0050] In an embodiment, the density of the processed material varies from 30% to 55% solid material. In this embodiment, the working pressure of the processed material is between 50 to 90 kPa. In this embodiment, the grinding apparatus is an autogenous or semi-autogenous mill.

[0051] In an embodiment, the density of the feed material varies from 35% to 60% solid material. In this embodiment, the working pressure of the processed material is between 40 kPa and 60 kPa. In this embodiment, the grinding apparatus is a ball mill.

[0052] In a further form, a mineral processing system is disclosed including:

a grinding apparatus configured to receive feed material and output a processed material; and

one or more hydrocyclones, each of the hydrocyclones comprising:

a body having a chamber, wherein the body includes one or more separate sections, and wherein the one or more sections are configured to be interchanged to obtain a selected particle size;

an inlet in communication with the chamber, the inlet configured to receive the processed material from the grinding apparatus;

a first outlet associated with the chamber, the first outlet configured to return a first stream to the grinding apparatus; and

a second outlet associated with the chamber, the second outlet configured to convey a second stream from the one or more hydrocyclones,

7

wherein at least part of a surface forming the chamber is substantially flat to

cause a directional change in the processed material present in the chamber.

[0053] In an embodiment, the surface is approximately located at the bottom of the

chamber. chamber.

[0054] In an embodiment, the surface is substantially flat to improve the classification

efficiency in the mineral processing system.

[0055] In an embodiment, the classification efficiency is above approximately 40%.

[0056] In an embodiment, the classification efficiency is above approximately 50%.

[0057] In an embodiment, the classification efficiency is above approximately 60%.

[0058] In an embodiment, particle size associated with the classification efficiency is

approximately 106 um. µm.

[0059] In an embodiment, the feed material to the grinding apparatus includes new

feed material and recirculated feed material.

[0060] In an embodiment, the new feed material includes material unprocessed by the

grinding apparatus.

[0061] In an embodiment, the new feed material to the grinding apparatus is above

750 wet metric tons/hour (wmt/h).

[0062] In an embodiment, the new feed material to the grinding apparatus is above

1000 wet metric tons/hour (wmt/h).

[0063] In an embodiment, the new feed material to the grinding apparatus is above

1250 wmt/h.

[0064] In an embodiment, the processed material that leaves the grinding apparatus is

separated into oversized and undersized particles using a mechanical screen.

[0065] In an embodiment, the undersized particles are directed to the inlet of the one

or more hydrocyclones.

[0066] In an embodiment, the recirculated feed material includes processed material

that has been separated by the one or more hydrocyclones and/or oversized particles that

have retained on the mechanical screen.

[0067] In an embodiment, the processed material includes magnetite ore.

[0068] In an embodiment, the surface is orientated transversely to one or more further

walls of the chamber.

[0069] In an embodiment, the surface is orientated perpendicular to the one or more

further walls of the chamber.

[0070] In an embodiment, the directional change includes a substantially

perpendicular directional change.

[0071] In an embodiment, the directional change includes two substantially

perpendicular directional changes.

[0072] In an embodiment, the one or more hydrocyclones includes at least two

hydrocyclones.

[0073] In an embodiment, the one or more hydrocyclones includes at least five

hydrocyclones.

[0074] In an embodiment, the one or more hydrocyclones includes ten hydrocyclones.

[0075] In an embodiment, the ten hydrocyclones include at least five hydrocyclones

that are operational.

[0076]

[0076] In an embodiment, the number of operational hydrocyclones is based on a

predetermined feed rate.

[0077] In an embodiment, the grinding apparatus and the one or more hydrocyclones

are arranged in a feedback loop.

[0078] In an embodiment, the grinding apparatus and the one or more hydrocyclones

are arranged in communication with a mechanical screen in the feedback loop.

[0079] In an embodiment, the mechanical screen is a vibrating screen.

[0080] In an embodiment, the mechanical screen is a trommel screen.

[0081] In an embodiment, the body includes one or more sections.

[0082] In an embodiment, the one or more sections are arranged to form a column. In

column.

[0083] In an embodiment, the one or more sections are wider than they are longer. In

axis of the one or more hydrocyclones.

[0084] In an embodiment, the one or more sections are sealed against each other.

9

[0085] In an embodiment, the one or more sections include at least two sections of

different sizes.

[0086] In In an an embodiment, embodiment, the the column column includes includes aa first first and and second second section section that that are are

longer than a third section. In an embodiment, length is defined in a longitudinal direction

along the one or more hydrocyclones. In an embodiment, the longitudinal direction extends

in a vertical direction.

[0087] In an embodiment, the column includes a first and second section that are of

the same length.

[0088] In an embodiment, the column includes a first section that is longer than a

second section.

[0089] In an embodiment, the one or more sections are configured to be interchanged

to obtain a selected particle size.

[0090] In an embodiment, the first outlet is located in the lower portion of the chamber.

[0091] In an embodiment, the first outlet is located in the surface of the chamber.

[0092] In an embodiment, a spigot or apex is located in the lower portion of the

chamber. chamber.

[0093] In an embodiment, the spigot or apex is located in the first outlet.

[0094] In an embodiment, the spigot is located in the side wall of the first outlet.

[0095] In an embodiment, silicon carbide is applied to the surface.

[0096] In an embodiment, silicon carbide is applied to the spigot.

[0097] In an embodiment, the one or more hydrocyclones produce a separation due to

the directional change of the material against the surface of the chamber whereby: i)

particles above approximately 300um 300µm are generally directed towards the first outlet; and ii)

particles below approximately 300um 300µm are generally directed to the second outlet.

[0098] In an embodiment, particles above approximately 0um Oµm to below 300um 300µm are

generally directed to the second outlet.

[0099] In an embodiment, particles above approximately 0um Oµm to below 150pm 150µm are

generally directed to the second outlet.

[00100] In an embodiment, the grinding apparatus may be an autogenous mill or a

semi-autogenous mill.

[00101] In an embodiment, the grinding apparatus may accept a feed material with a 07 Aug 2025

P80 of 100 to 200-mm.

[00102] In an embodiment, the autogenous mill has a cut size of 106 to 150 µm.

[00103] In an embodiment, the semi-autogenous mill has a cut size of 37 to 75 µm.

[00104] In an embodiment, the density of the processed material varies from 30% to 55% solid material.

[00105] In an embodiment, the working pressure of the processed material is between 2021466603

50 to 90 kPa.

[00106] In an embodiment, the grinding apparatus is a ball mill.

[00107] In an embodiment, the grinding apparatus is configured to accept a feed material with a P80 of 10-25 mm.

[00108] In an embodiment, the ball mill has a cut size of 37 to 75 µm.

[00109] In an embodiment, the density of the feed material varies from 35% to 60% solid material.

[00110] In an embodiment, the working pressure of the processed material is between 40 kPa and 60 kPa.

[00111] In an embodiment, a hopper is arranged in the feedback loop between the mechanical screen and the one or more hydrocyclones.

[00112] In an embodiment, the vibrating screen is a double deck vibrating screen.

[00113] In an embodiment, the mineral processing system assists in reducing the particle size of the feed material from a P80 of 100-200 mm to a P80 of 100-200 μm. In this embodiment, an autogenous mill or a semi-autogenous mill is utilised in the mineral processing system.

[00114] In an embodiment, the mineral processing system assists in reducing the particle size of the feed material from a P80 of 10-20 mm to a P80 of 100-200 μm. In this embodiment, a ball mill is utilised in the mineral processing system.

[00115] In a further form, a method for processing minerals is disclosed, the method including the steps of:

processing a feed material in a grinding apparatus to produce a processed material;

conveying the processed material to one or more hydrocyclones, each of the hydrocyclones being in the form of the invention;

11 --

separating components from the processed material into a first stream and a

second stream using one or more hydrocyclones, wherein part of the material has a

directional change to separate the streams;

returning the first stream the grinding apparatus; and

forfurther conveying the second stream downstream for furtherprocessing. processing.

[00116] In an embodiment, wherein the step of processing the feed material includes

processing magnetite.

[00117] In an embodiment, the method further includes the steps of:

the processed material entering a body of the one or more hydrocyclones, the body

having a chamber, wherein at least part of a surface of the chamber is substantially

flat to cause the directional change in the processed material present in the

chamber;

the processed material undergo the directional change when coming into contact

with the surface.

[00118] In an embodiment, the directional change provides a coarser material being

directed to the first stream compared to the second stream.

[00119] In an embodiment, the method further includes the steps of:

conveying the processed material from the grinding apparatus to a mechanical

screen;

subjecting the processed material to a classification step;

conveying the remaining processed material to a hopper;

mixing the remaining processed material with water; and

pumping the processed material to the one or more hydrocyclones.

[00120] Further features and advantages of the present disclosure will become

apparent from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[002] Various preferred embodiments of the present disclosure will now be described, by

way of examples only, with reference to the accompanying figures, in which:

12 -

Figure Figure 1 1illustrates illustratesa flowdiagram relating a flowdiagram to a mineral relating processing to a mineral system, processing system,

according to an embodiment of the invention;

Figure 2 illustrates a front view of a conventional hydrocyclone;

Figure 3 illustrates a front view of a flat bottom hydrocyclone for use in the mineral

processing system of Figure 1;

Figures 4(a)-(c) illustrate variations of the flat bottom hydrocyclone in Figure 3,

wherein 4(a) is a front view of a standard sized flat bottom hydrocyclone; 4(b) is a front view

of a short flat bottom hydrocyclone; and 4(c) is a front view of an extra short flat bottom

hydrocyclone; and

Figures 5 to 7 illustrate flow diagrams relating to the mineral processing system of

Figure 1, according to various embodiments of the invention.

DETAILED DESCRIPTION

[00121] Figure 1 provides an illustration of a mineral processing system 10i, according

to an embodiment of the invention. In this regard, the use of a reference numeral followed

by a lower case letter typically indicates alternative embodiments of a general element

identified by the reference numeral in this specification. Thus, for example, mineral

processing system 10a is similar to but not identical to the mineral processing system 10b.

Further, references to an element identified only by the numeral refer to all embodiments of

that element. Thus for example a reference to mineral processing system 10 is intended to

include (for instance) the mineral processing system 10i, mineral processing 10a, mineral

processing system 10b and mineral processing system 10c.

After

[00122] After ironiron ore ore is removed is removed fromfrom a mine, a mine, there there are are a number a number of steps of steps involved involved in in

processing the extracted ore. The process of reducing the ore in size and separating the

valuable components from the undesired materials is known as ore beneficiation. These

steps steps may mayinclude includescreening the ore screening the to separate ore fine particles to separate and then crushing, fine particles and then grinding crushing, grinding

and separating the desired particles from other materials. This separation is achieved

through two steps known as screening and classification.

Classification

[00123] Classification isisthe theprocess process of of separating separatingout particles out by size particles based based by size on theon the

particle's behaviour in a flowing material (air or water). Because classification can be a

complicated process, the energy used during ore beneficiation is considerably influenced

by the efficiency of the classification operation. For wet classification, the key properties are

the particle's size and density. The heavier and denser particles should settle while the finer

and lighter particles should be carried along more easily within the liquid. Therefore, classification efficiency is based on how successful this separation between particles with these varying properties is. In other words, classification efficiency is generally defined as the fraction (or percentage) of the feed material of a given size which is recovered in a stream. Increasing the classification efficiency is crucial to optimising the operational costs of the grinding process and subsequently, the whole plant.

[00124] As part of the mineral processing system 10i, new feed material 100 undergoes

a crushing step (not shown). New feed material 100 is delivered to one or more crushing

device(s). This new feed material 100 contains magnetite ore. The crushing device could

be any one of the following: jaw crushers, gyratory crushers, cone crushers or high

pressure grinding rolls. However, it will be appreciated that the crushing device is not limited

to these options. The crushing device, typically, reduces new feed material 100 from a

diameter up to 1200 mm to a diameter less than 350 mm.

[00125] The specific particle size to be conveyed to other parts of the mineral

processing system 10i depends on (amongst other things) the grinding apparatus, such as

grinding apparatus 200i, that is to be used within the mineral processing system 10i. If an

Autogenous (AG) mill or Semi-autogenous (SAG) mill is to be used, new feed material 100

is typically crushed only by a single crusher to obtain coarse particles with a dimension up

to P80 approximately 100-200 mm. If a ball mill is to be used, new feed material 100 is

crushed by two or more crushers operating in parallel to obtain fine particles with an

approximate particle P80 size of 10-20 mm or smaller. The grinding apparatus 200i will be

discussed in further detail below.

[00126] After the crushing step, the new feed material 100 is conveyed to a primary

grinding circuit of the mineral processing system 10i. The primary grinding circuit is the first

stage of the grinding process and involves two main instruments, a grinding apparatus 200i

and a classifier or hydrocyclone 300i. The grinding apparatus 200i grinds the feed material

to a smaller size, and the classifier or hydrocyclone 300i divides the ground products into

desired and undesired products. From here, the undesired material is returned to the

grinding apparatus 200i for re-grinding.

[00127] The mineral processing system 10i may assist in reducing the ore particle size

from a P80 (80% P (80% out out the the output output product) product) ofof 100-200 100-200 mmmm (for (for anan AGAG mill mill oror SAG SAG mill) mill) oror 10-20 10-20

mm mm (for (forball ballmill) to to mill) a P80 a Pofof 100-200 um. µm. 100-200

[00128] The feed material 100' that enters the grinding apparatus 200i includes new

feed material 100 and recirculated feed material. The recirculated feed material includes

material that has been processed by the hydrocyclone 300i and undesirable (oversized) particles that have been retained on the mechanical screen 400. The mechanical screen

400 and the hydrocyclone 300i will be discussed in further detail below.

[00129] The grinding apparatus 200i is used to grind the feed material 100' into smaller

particles. Grinding has two main purposes: to break open the ore rock crystals so that the

minerals inside can be accessed (and then separated from the mixture); and to produce

mineral filler, which is a fine inert mineral matter.

[00130] The grinding apparatus 200i could be any one of an Autogenous (AG) mill,

Semi-autogenous (SAG) mill or ball mill, or a combination of such apparatus. However, it

will be appreciated that such a grinding apparatus 200i is not limited to these options. As

discussed above, Autogenous (AG) mill or Semi-autogenous (SAG) mill often require new

feed material 100 to take the form of coarse ore. This is because new feed material 100

forms, at least, part of the grinding media in the grinding apparatus 200i when an AG mill

or SAG mill is used. The autogenous mill uses a cut size of approximately 106 to 150um 150µm

during the grinding process but this may be higher. Conversely, the semi-autogenous mill

uses a cut size of approximately 37 to 75 um. µm.

[00131] New New feedfeed material100 material 100consisting consisting of of fine fineore oreisis preferred whenwhen preferred utilising a balla ball utilising

mill. This is because a ball mill uses its own grinding media, e.g. steel grinding balls, to aid

in the grinding process. The ball mill has a cut size of approximately 37 to 75 um. µm.

[00132] The feed material 100' is termed a processed material 150, in this specification,

once it has left the grinding apparatuses 200. However, it will be appreciated that, for

example, the feed material 100' is partially processed and the processed material 150 may

be further processed by, for instance, the hydrocyclones 300.

After

[00133] After the the grinding grinding step, step, the the processed processed material material 150 150 is conveyed is conveyed to atomechanical a mechanical

screen 400 for classifying. The mechanical screen 400 could be a rotary screen, such as a

trommel screen, or a vibrating screen; however, the invention is not limited to these

devices. The purpose of the screen is to separate the ground ore into multiple grades

through classification of particle size.

[00134] In Figure 1, a vibrating screen 400i is used as the mechanical screen. A

vibrating screen is, typically, used when smaller size material needs to be classified. The

vibrating screen 400i consists of a screen media placed on a spring-mounted frame, where

the frame could be horizontal or on an incline. The screen media is formed of one or more

layers which include a series of openings. If there is more than one layer, the openings of

each consecutive layer diminish in size. The screen media is pulled tight across the frame.

When the processed material 150 is shaken through throug hthe thevibrating vibratingscreen screen400i, 400i,the thevibrating vibrating screen 400i separates out particles of an undesirable size. The remaining processed material 150 will contain a selected particle size.

[00135] Following the mechanical screen 400, the undesired particles can take a

number of different paths. These paths are dependent on the chosen grinding apparatus

200 to be used in the mineral processing system 10.

[00136] For system 10i, when an AG mill or SAG mill is used as the grinding apparatus

200i, the undesired particles from the mechanical screen 400i are delivered back to a

pebble crusher 700i for further crushing or directly returned to the grinding apparatus 200i

through a return pathway 500i. When a ball mill is used as the grinding apparatus 200i, the

undesired particles are often rejected. This is because the undesired particles from the ball

mill consist of grinding media scats, extra coarse ore lumps or foreign objects.

[00137] Following Following the the mechanical mechanical screen screen 400i, 400i, the the processed processed material material 150 150 is conveyed is conveyed

to a hydrocyclone 300i. The hydrocyclone 300i is a type of classifier. As discussed above in

relation to classification, classifiers are used to separate and sort materials based off their

density, shape and size. They operate by distinguishing between the various settling

velocities of the different particle sizes that make up a processed material 150. The use of

classifier aids in improving the quality of the product material. In one embodiment of the

present invention, ten hydrocyclones 300i are used and the number of operational

hydrocyclones is varied based on the feed rate thereto.

[00138] WhenWhen an autogenous an autogenous or semi-autogenous or semi-autogeno mill us mill hashas been been utilised utilised as as thethe grinding grinding

apparatus 200i, the density of the processed material 150 will preferably vary from 30% to

55% solid material. In this embodiment, the working pressure of the processed material 150

is between 50 to 90 kPa.

[00139] When a ball mill has been utilised as the grinding apparatus 200i, the density of

the processed material 150 preferably varies from 35% to 60% solid material. In this further

embodiment, the working pressure of the processed material 150 is between 40 kPa and

60 kPa.

[00140] Classification can, to an car to an extent, extent, be be undertaken undertaken by by aa spiral spiral classifier. classifier. However, However, in in

the present disclosure, the classification is undertaken by a hydrocyclone 300i and this will

be discussed in further detail with reference to Figures 2 and 3.

[00141] Figure 2 illustrates a front view of a conventional prior art hydrocyclone. The

shape of a conventional hydrocyclone is a cylindrical section 270 positioned above and in

communication with a conical section 250. A conventional hydrocyclone has a conventional

feed inlet 210 to allow the processed material 150 to enter the cylindrical section 270, and

two output pathways for the different components. Centrifugal forces are created from the

entry of the processed material 150. This forces the heavier material to the walls of the

16 -

hydrocyclone and down the conical section 250, while leaving the remaining liquid spinning.

The conventional vortex finder 280 keeps increasing the speed of the remaining liquid

which eventually exits the hydrocyclone through a conventional overflow pathway 230.

[00142] Due to the conical shape of the conventional hydrocyclone, the heavier material

increases in speed and hereby increases the separation efficiency of this material. This

heavier material leaves the hydrocyclone through the conventional underflow pathway 240.

A conventional

[00143] A conventional hydrocyclone, with hydrocyclone, with aa cylindrical cylindricalsection and and section conical section, conical is section, is

the most common type integrated into mineral processing as it has traditionally been the

most suitable separator. For example, in a SAG mill or ball mill grinding circuit, the cut size

is often at around 37-75 um, µm, hence the conventional hydrocyclone is capable of handling

the classification process required. However, for an AG mill circuit (for instance), the

required cut size often increases to 106-150 um, µm, and sometimes even higher (eg, 300um 300µm

etc). This higher cut size can affect what is referred to as the separation or cut point of the

hydrocyclone is employed in this type of circuit, it can lead to a number of problems due to

the finer material flowing through the circuit.

[00144] For example, if more fine material is bypassed to the cyclone underflow, this

can lead to an increase of circulating load and the possibility of overgrinding. This can in in

turn lead to restriction of the milling throughput due to a high charging load in the mill

caused by high circulating load. Roping and associated problems frequently occur due to

high feed density caused by high circulating load as well, resulting in coarse particles being

conveyed to further downstream. This can lead to damage of the downstream equipment

and, in some situations, can cause a widespread breakdown across the whole production

line.

[00145] Figure 3 depicts a front view of a flat bottom hydrocyclone 300i for use in a

mineral processing system 10i as described in the present invention. Compared with the

conventional hydrocyclone as shown in Figure 2, a flat bottom hydrocyclone 300i is

cylindrically-shaped cylindrically-shaped with with aa flat flat bottom bottom as as shown shown in in Figure Figure 3. 3. Flat Flat bottom bottom hydrocyclones hydrocyclones

have been developed, such as those found in Chinese patent No. 200620084869 and

Chinese patent No. 201721898633.4. However, these hydrocyclones suffer from a number

of issues and (for example) are not adapted for processing magnetite. Furthermore,

hydrocyclones with varied column lengths are installed in the cyclone cluster of the present

invention. This allows the same hydrocyclones with different column lengths or a

17 --

combination of different hydrocyclones with varied column lengths to achieve a target

overflow P80 size P size according according toto process process requirements. requirements.

[00146] The flat bottom hydrocyclone has a cylindrical upper body 305i which has a

feed inlet 310i. The feed inlet 310i is configured to receive a processed material 150 from

the grinding apparatus 200i. The flat bottom hydrocyclone 300i has a cylindrical shaped

lower body 320i, wither substantially vertical outer wall(s), having a diameter smaller that

the upper body 305i. The lower body 320i is formed from a number of sections 350i. An end

wall 360i, which is substantially perpendicular to the outer walls of the lower body 320i,

forms a 'flat bottom'. The inner walls of the upper body 305i and lower body 320i form a

chamber to which the feed inlet 310i is coupled. A first outlet 340i provides an underflow

pathway associated with the chamber and is configured to return a first stream to the

grinding apparatus 200i. A second outlet 330i associated with the chamber provides an

overflow pathway for classified product.

[00147] The processed material 150 enters the chamber under a working pressure. The

pressure of the material creates centrifugal forces within the chamber. Centrifugal force

pushes the heavier or coarser material towards and down the walls of the chamber. The

end wall 360i causes a directional change in the processed material 150 present in the

chamber. That is, the end wall 360i causes the processed material 150 to substantially

change in a perpendicular direction towards underflow outlet 340i. Due to the directional

change of the end wall 360i, improved classification efficiency occurs in the mineral

processing system, as less fine material is directed to the underflow pathway (first outlet

340).

[00148] To explain this in more detail, the chamber has two output pathways for the

different components. The heavier particles of the processed material 150 passes through

the underflow pathway 340i. The processed material 150 leaves the flat bottom

hydrocyclone 300i through a spigot 370i found in the underflow pathway 340i. The spigot

370i could also be an apex under an embodiment of the invention.

[00149] To assist with a bed of coarse solids rotating and circulating on the end wall

360i, causes grooving in the end wall 360i and spigot 370i, a wear-resisting material is

applied to the components to prolong their service life. In one embodiment, silicon carbide

is applied to the flat surface 360i and the spigot 370i.

[00150] The processed material 150 that leaves through the underflow pathway 340i

returns to the grinding apparatus for further grinding.

[00151] The vortex finder 380i increases the speed of the liquid and finer material that

has separated from the heavier material. The finer material, and any accompanying liquid,

exits the flat bottom hydrocyclone 300i through the overflow pathway, via second outlet

330i. The finer material forms the desired product of the mineral processing system 10i. The

finer material is conveyed downstream to be processed further.

Figure

[00152] Figure 4(a)-(c) 4(a)-(c) depictsvarious depicts various embodiments embodimentsofof different flatflat different bottom bottom

hydrocylcones, according to the present invention, wherein (a) is a front view of a standard

sized flat bottom hydrocyclone; (b) is a front view of a short flat bottom hydrocyclone; and

(c) is a front view of an extra short flat bottom hydrocyclone. Each of these configurations

are considered to be a flat bottom hydrocyclone 300 as that described with reference to

Figure 3.

[00153] In a similar manner to hydrocyclone 300i, each of the hydrocyclones 300a,

300b, 300c shown Figures 4(a), 4(b) and 4(c) include sections 350 arranged to form the

lower body 320. The sections 350 are arranged vertically to form a column. That is, the

sections 350 are stacked on top of one another to form the column. A chamber is formed

inside of the column. The one or more sections 350i may be sealed against each other.

[00154] The sections 350 are configured to be interchanged to obtain a desired overflow

particle size. particle size.When a coarser When overflow a coarser particle overflow size issize particle desired, the lower the is desired, bodylower 320 can be 320 can be body

reconfigured with the sections 350. This ability to reconfigure the sections 350 provides an

advantage over conventional hydrocyclones which cannot be configured in the same

manner.

[00155] The sections 350 may be different sizes. As shown in Figure 4(a), the

hydrocyclone 300a includes two sections 350a, 350b of the same height/length and one

section 350c of a smaller height/length. This formation is referred to as a standard flat

bottom hydrocyclone 300a. The standard flat bottom hydrocyclone 300a has larger internal

volume and longer time for classification which helps to increase the fineness of overflow.

[00156] An embodiment can be formed by removing a short section 350c from the body

320a of the standard flat bottom hydrocyclone 300a. This configuration is referred to as a

short flat bottom hydrocyclone 300b. A further embodiment can be formed by removing a

long section 350b from the body 320a of the standard flat bottom hydrocyclone 300a. This

is referred to as an extra short flat bottom hydrocyclone 300c.

[00157] The short flat bottom hydrocyclone 300b and extra short flat bottom

hydrocyclone 300c produce a shorter classification time, shorter column length, and smaller

tangential velocity loss. These factors strengthen the centrifugal intensity at end wall 360b,

360c and help to reduce the proportion of fine particles remaining in the processed material

150 that leaves the chamber through the underflow pathway 340.

PCT/AU2021/051148

- 19 -

[00158] Figure 5 provides an embodiment of the mineral processing system 10a for

improving the classification efficiency in primary grinding circuit. This embodiment

preferably includes an AG mill or SAG mill as the grinding apparatus 200a. A vibrating

screen is preferably included as the mechanical screen 400a. One flat bottom hydrocyclone

300i is included in the system 10a but, in further embodiment, multiple hydrocyclones 300

may be included. Each apparatus is employed in a feedback loop.

[00159] New feed material 100 may have a particle P80 size of 100-200 mm. New feed

material 100 is conveyed to the grinding apparatus 200a. Water may be included as part of

the grinding process to obtain a desired grinding density. The grinding apparatus 200a

includes a mill grate. Following the grinding step, the processed material 150 is discharged

from the grinding apparatus 200a through the mill grate. The processed material 150 is

conveyed to the mechanical screen 400a. The mechanical screen 400a is a vibrating

screen. The vibrating screen is employed with double decks, aiming at increasing the

screening efficiency.

[00160] The undesired particle sizes of the processed material 150 are returned to the

crushing step. As shown in Figure 5, the undesired material is conveyed to a bin 750 and

feeder 780 before being transferred into a pebble crusher 700a. The crushed pebbles then

return to the grinding apparatus 200a. In an alternative embodiment, the undesired particle

sizes are returned to the grinding apparatus 200a.

[00161] The remaining (undersized) processed material 150 flows to a slurry hopper

600a. The processed material 150 is mixed with water or another suitable fluid in the slurry

hopper 600a to form another processed material 150 before being pumped to one or more

flat bottom hydrocyclones 300i. Preferably, the density of the processed material 150 after

it leaves the slurry hopper 600 will vary from 30% to 55% solid material. Preferably, the

working pressure of the processed material 150 varies from 50 kPa to 90 kPa. The process

capacity for each of the one or more flat bottom hydrocyclones 300i, in this embodiment, is

approximately 750 to 900 cubic metres per hour.

[00162] The processed material 150 then passes through the flat bottom hydrocyclone

300i. Afterbeing After beingsubjected subjectedto tocentrifugal centrifugalforces forceswithin withinthe theflat flatbottom bottomhydrocyclone hydrocyclone300i, 300i,the the

heavier particles of the processed material 150 pass through the underflow pathway 340i.

This part of the processed material 150 then returns to the grinding apparatus 200a for

further grinding. The finer material, and accompanying liquid, exits the flat bottom

hydrocyclone 300a through an overflow pathway 330i. The finer material is conveyed

downstream to be processed further.

[00163] Figure 6 provides a further embodiment of the mineral processing system 10b

for improving the classification efficiency in primary grinding circuit. This embodiment

includes a ball mill as the grinding apparatus 200b. A trommel screen is utilised as a

mechanical screen 400b. A number of flat bottom hydrocyclones 300i form a cluster. Each

apparatus is employed in a feedback loop.

[00164] New feed material 100 may have a particle P80 size of 10-20 mm or smaller.

New feed material 100 is conveyed to the grinding apparatus 200b. In this embodiment, the

grinding apparatus 200b is a ball mill. Water may be included as part of the grinding process

to obtain a desired grinding density. Grinding media, such as steel grinding balls, should be

added regularly.

[00165]

[00165] The ball mill includes a discharge outlet. A mechanical screen 400b is installed

on the discharge outlet of the ball mill. The mechanical screen 400b takes the form of a

trommel screen. The undesired material discharged from the trommel screen, i.e. scats, are

disposed of.

[00166] The remaining processed material 150 flows to a slurry hopper 600b. The

processed material 150 is mixed with water or another suitable fluid in the slurry hopper

600b before being pumped to flat bottom hydrocyclones 30 Oi. 0i. Preferably, the density of the

processed material 150 after it leaves the slurry hopper 600b will vary from 35% to 60%

solid material. Preferably, the working pressure of the processed material 150 varies from

40 kPa to 60 kPa.

[00167] The processed material 150 then passes through the flat bottom hydrocyclones

300i. After being subjected to centrifugal forces within the flat bottom hydrocyclone 300i, the

This part of the processed material 150 then returns to the grinding apparatus 200b. The

finer material, and accompanying liquid, exits the flat bottom hydrocyclone 300i through an

overf pathway overflow 330i. pathway TheThe 330i. finer material finer is conveyed material downstream is conveyed to be downstream to processed further. be processed further.

Example

[00168] A further mineral processing system 10c is provided in Figure 7. This system

10c processes magnetite ore. A combination of an autogenous mill with a vibrating screen

and a pebble crusher, together with a hydrocyclone cluster, form a feedback loop whereby

at least part of the material is circulated therearound. As shown in Figure 7, the mineral

processing system 10c consists of a grinding apparatus 200c, a mechanical screen 400c,

a slurry hopper 600c, a feed pump 800c, flat bottom hydrocyclones 300i and pebble crushers 700c. The grinding apparatus 200c is an AG mill and the mechanical screen 400c is a double deck vibrating screen.

[00169] New New feedfeed material material 100 100 of the of the feedfeed material material 100'100' includes includes broken broken ore ore fromfrom an an

open pit. New feed material 100 has a F80 of around 300-350 mm. New feed material 100

may be delivered to the primary crushers by a fleet of haul trucks. Preferably, the primary

crushers are gyratory crushers. New feed material 100 may be delivered to the crushed ore

stockpile by conveyor belts. New feed material 100 is preferably fed to the grinding

apparatus 200c through the use of apron feeders and conveyor belts.

[00170] The The processed processed material material 150 150 is discharged is discharged fromfrom the the grinding grinding apparatus apparatus 200c. 200c.

The processed material 150 is then conveyed to the mechanical screen 400c. The desired

particle sizes remain in the processed material 150 which is then conveyed to a slurry

hopper 600c. The undesired (oversized) particles are returned to the pebble crushers 700c.

The processed material 150 is then pumped to the flat bottom hydrocyclones 300i by the

feed pump 800c.

[00171] The flat bottom hydrocyclones 300i are configured in a cluster. The number of

hydrocyclones in the cluster may vary and, for example, can include ten flat bottom

hydrocyclones 300i. Each of the flat bottom hydrocyclones contained in the cluster does not

need to be operational at any one time. The number of operational hydrocyclones is based

on a predetermined feed rate.

[00172] The capacity associated with each of the flat bottom hydrocyclones 300i is

approximately 750 to 900 cubic metres per hour (m 3/h).The (m³/h). Theprocessed processedmaterial material150 150can canbe be

delivered to the cluster at a cluster feed rate 4500-5400 m³/h to be spread amongst the

hydrocyclones. This cluster feed rate can vary based on the new feed material 100 and

hydrocyclone recirculation rate. This is because the feed material to the grinding apparatus

200c can include fresh or new feed material, which has not been processed by the

hydrocyclones, and recirculated feed material that includes material that has been

processed by the hydrocyclones and recirculated crushed pebbles (e.g., particles that have

been retained on the mechanical screen 400c) if any.

A first

[00173] A first stream stream exits exits the the one one or more or more flatflat bottom bottom hydrocyclones hydrocyclones 300i300i through through an an

underflow pathway. underflow pathway.TheThe first stream first is returned stream to the to is returned grinding apparatusapparatus the grinding 200c for further 200c forfurther

grinding. A second stream exits the one or more flat bottom hydrocyclones 300i through an

overflow pathway. The second stream is conveyed downstream for further processing.

In this

[00174] In this embodiment, embodiment, conventional conventional conecone hydrocyclones hydrocyclones withwith a diameter a diameter of 840 of 840

mm were configured in the original AG mill circuit. It was found that problems would arise and, in some cases, production incidents would occur, due to the inability of the conventional cone hydrocyclones to fully accommodate the variation of operating conditions in the primary grinding circuit. The problems observed in the conventional cone hydrocyclone underflow included surging, roping and plugging. Notably, this occurred when the particle size distribution of conventional hydrocyclone feed material varied which happened when there were fluctuations in the AG mill grinding performance. This resulted in coarse particles reporting to downstream magnetic separators. These coarse particles could result in damage to the magnetic separator drums found downstream or block the feed pipelines of the magnetic separators, which could lead to whole line breakdown.

In addition,

[00175] In addition, some some fineparticles fine particles below belowthe thecut size, cut which size, should which have exited should via have exited via

the overflow pathway of the conventional cone hydrocyclone, were exiting via the underflow

pathway. This caused an increase in the circulating load and subsequently decreased the

throughput of the AG mill. Based on the original design, the cyclone overflow P80 should P should bebe

around around 180 180um, butbut µm, thethe actual overflow actual P 80 was overflow onlyonly P was 50-7050-70 um, significantly restricting µm, significantly AG restricting AG

mill throughput.

[00176] In order to resolve the abnormal production conditions and improve the

circulating load and throughput of the AG mill, flat bottom hydrocyclones 300, as described

above, were introduced and tested in the primary grinding circuit.

Example 1

Example

[00177] Example 1 involved 1 involved a series a series of comparative of comparative trials trials thatthat werewere performed performed to to

evaluate the feasibility of the present invention for increasing classification efficiency and

decreasing circulating load in primary grinding circuit.

[00178] There There werewere 14 sets 14 sets of conventional of conventional conecone hydrocyclones, hydrocyclones, eacheach withwith a diameter a diameter

of 840 mm, a spigot with a diameter of 180 mm and a vortex finder with a diameter of 400

mm configured in the original cone hydrocyclone cluster. Normally, five to six conventional

cone hydrocyclones would be running at any one time. The conventional cone

hydrocyclones were run with a working pressure of 50-60 kPa. Seven flat bottom

hydrocyclones 300i, as described above, with a diameter of 840 mm, a spigot with a

diameter of 150 mm and a vortex finder with a diameter of 340 mm were installed in the

cluster to replace the conventional cone hydrocyclones.

[00179] The comparative trials are carried out between the conventional hydrocyclones

and the flat bottom hydrocyclones. The feed material 100 conveyed to each hydrocyclone

had the same conditions, such as the particle size distribution, density and working

pressure.

[00180] The following table (Table 1) compares the analysis of each set of

hydrocyclones during the trial.

Table 1: Example 1 trial results

New feed Circulating Classification Classification material to Hydrocyclone Hydrocyclone Overflow Batch Density, % -106um% load @ 106 efficiency @ 106 AG mill, -106pm% Type product P80, % um, µm, % um, µm, % wmt/h

Feed 46.57 46.96

0840mm Overflow 25.68 91.47 Conical 72 227 54.67 1 Underflow 75.05 75.05 27.34 1179 Hydrocyclone

0840mm Flat Overflow 32.82 77.32 Bottom 120 116 56.37 Underflow 72.05 20.84 Hydrocyclone

Feed 50.00 36.99

0840mm Overflow 21.12 96.94 Conical 47 557 39.15 39.15 Underflow 79.72 79.72 26.22 2 1089 Hydrocyclone

0840mm Flat Overflow 27.04 87.19 Bottom 87 269 58.37 Underflow 70.45 18.32 Hydrocyclone

Feed 48.38 40.43

0840mm Overflow 22.13 90.79 Conical 74 314 50.51 Underflow 77.57 77.57 24.39 3 1134 Hydrocyclone

0840mm Flat Overflow 29.22 76.96 Bottom 120 148 61.16 61.16 Underflow 76.28 15.75 Hydrocyclone

Feed 47.38 43.39

0840mm Overflow 21.6 92.76 Conical 65 309 49.17 Underflow 75.2 27.4 4 1135 Hydrocyclone

0840mm Flat Overflow 31.55 76.05 76.05 Bottom 125 123 59.56 59.56 Underflow 76.23 16.89 16.89 Hydrocyclone

Feed 45.92 43.14

0840mm Overflow 24.22 90.43 1369 Conical 69 238 57.06 Underflow 80.5 23.26 Hydrocyclone

24 -

0840mm Flat Overflow 28.73 82.49 Bottom 97 134 68.47 Underflow 81 13.84 Hydrocyclone

Feed 45.14 41.7

0840mm Overflow 23.08 96.96 Conical 44 335 52.25 Underflow 72.87 25.2 6 1428 Hydrocyclone

0840mm Flat Overflow 29.55 81.07 Bottom 101 139 67.62 Underflow 79.14 13.47 Hydrocyclone

Feed 41.48 50.05

0840mm Overflow 26.04 90.3

Conical 47 178 66.97 66.97 73.6 19.22 Underflow 7 1175 Hydrocyclone

0840mm Ø840mm Flat Overflow 21.99 96.59 Bottom 76 131 69.83 69.83 76.73 23.9 Underflow Hydrocyclone

Feed 43.68 45.79 45.79

0840mm Overflow 20.46 98.59 Conical 38 480 36.65 36.65 Underflow 60.39 34.80 8 1485 Hydrocyclone

0840mm Ø840mm Flat Overflow 26.37 87.25 Bottom 82 160 64.14 Underflow 71.57 19.94 Hydrocyclone

Feed 44.19 43.16

0840mm Overflow 29.35 96.19 Conical 46 234 64.70 64.70 Underflow 69.95 20.51 9 1428 Hydrocyclone

0840mm Flat Overflow 24.11 82.87 Bottom 95 128 71.08 Underflow 78.45 78.45 12.07 Hydrocyclone

Feed 49.30 34.80

0840mm Overflow 28.32 96.38 Conical 44 397 54.61 Underflow 78.34 78.34 19.29 1492 Hydrocyclone

0840mm Flat Overflow 21.94 81.15 Bottom 101 227 62.54 Underflow 77.57 14.35 Hydrocyclone

Feed 46.09 40.23 11 1428 Overflow 22.05 97.72 42 556 36.45 0840mm

Conical Underflow 70.73 70.73 29.89 Hydrocyclone

0840mm Flat Overflow 29.74 79.26 Bottom 107 154 63.93 Underflow 79.82 14.87 Hydrocyclone

Feed 39.12 48.51

0840mm Overflow 21.05 97.26 Conical 40 208 63.29 Underflow 71.08 25.12 12 1185 Hydrocyclone

0840mm Ø840mm Flat Overflow 24.58 92.71

Bottom 63 155 69.40 Underflow 71.87 19.99 Hydrocyclone

Feed 42.07 49.35

0840mm Overflow 26.22 82.20 Conical 100 146 53.33 Underflow 83.80 26.92 13 1255 Hydrocyclone

0840mm Ø840mm Flat Overflow 30.14 83.36 Bottom 97 102 67.48 Hydrocyclone Underflow 78.13 78.13 15.89

Feed 46.74 39.55

0840mm Overflow 20.69 95.71

Conical 60 360 51.09 Underflow 72.68 72.68 23.94 14 1422 Hydrocyclone

0840mm Flat Overflow 27.25 79.37 Bottom 107 161 63.81 Underflow 77.45 77.45 14.82 14.82 Hydrocyclone

Feed 40.12 49.20

0840mm Overflow 21.67 96.39 96.39 Conical 50 407 37.21 Underflow 62.78 37.62 1319 Hydrocyclone

0840mm Flat Overflow 25.61 90.93 Bottom 80 184 58.87 58.87 Underflow 73.28 26.48 Hydrocyclone

[00181] The trial results indicate that, compared to conventional cone hydrocyclones,

the flat bottom hydrocyclones (in the systems 10) have significant advantages for use in

primary grinding circuits. These advantages are as follows:

The operating status for flat bottom hydrocyclones was more stable.

It was found that spigot roping or issues with the spigot being plugged were rare and

involved blockage via a foreign object.

Flat bottom hydrocyclones in the systems 10 had a greater flexibility to

accommodate the fluctuation of the AG mill throughput and feed density.

The underflow of the flat bottom hydrocyclones included a significant reduction in

fine material. Fine material in the underflow was reduced by 10%. This

subsequently provided a better material size distribution when the fine material

reached downstream processing.

The overflow P 80 size size (considered (considered to to be be 80%80% of of thethe particles particles passing passing through) through)

increased by 30-50 um µm in comparison to that of the conventional cone

hydrocyclone.

The circulating load for the present flat bottom hydrocyclones was 110-170%. This

was reduced substantially from that of conventional cone hydrocyclones, where the

circulating load was 250-300% for conical cyclones.

The classification efficiency for the present flat bottom hydrocyclones is averaged

at around 64%, an increase of 13% when compared to conventional cone

hydrocyclones.

The AG mill throughput increased by 10-15% with the present flat bottom

hydrocyclones.

Example 2

[00182] An advantage of replacing the conventional cone hydrocyclones with flat

bottom hydrocyclones 300 is to shift the load from the primary grinding circuit to further

downstream. However, it was found that there was still a significant gap between observed

between the calculated P 80 size size in in thethe flat flat bottom bottom hydrocyclone hydrocyclone overflow overflow pathway pathway andand AG AG

mill throughput and the results that were being recorded.

In order

[00183] In order to to furthercoarsen further coarsen the the PP 80 sizeexiting size exiting the the cluster cluster of offlat flatbottom bottom

hydrocyclones 300 and increase the AG mill throughput, the standard flat bottom

hydrocyclone was modified to shorten the classification time for obtaining coarser particle

sizes. These configurations have been discussed above and are depicted in Figure 4(a-c).

These configurations are referred to as a short flat bottom hydrocyclone 300b and an extra

short flat bottom hydrocyclone 300c.

27 - -

[00184] The comparative trials for each of the three configurations of the flat bottom

hydrocyclone were performed in parallel within the same flat bottom hydrocyclone cluster.

Each hydrocyclone was equipped with the same diameter of 840 mm, spigot of 150 mm and

vortex finder of 340 mm. The results of Example 2 are listed in Table 2.

Table 2: Trial results for three different types of FBH

New feed Flat bottom Classification Hydrocyclone Circulating load Batch material to AG hydrocyclone Density, % um, % -106 µm, um, efficiency @ 106 µm, product @ 106 um, µm, % mill, wmt/h type % Feed 41.40 40.66

Overflow 29.74 74.89 Standard Standard 108 69.41 Underflow 86.05 8.85

1 Overflow 1231 37.23 54.85 Short 45 48.49 Underflow 82.34 9.07

Overflow 38.50 50.82 Extra Short 31 42.45 Underflow 83.61 8.23

Feed 41.72 38.36

Overflow 23.57 23.57 81.89 Standard 144 74.95 Underflow 83.96 8.09

2 1261 Overflow 25.37 74.98 Short 125 69.08 Underflow 80.00 80.00 9.08 9.08

Overflow 28.79 28.79 72.82 72.82 Extra Short 114 69.19 69.19 Underflow 81.89 81.89 8.12

[00185] The results showed that both the short flat bottom hydrocyclone 300b and the

extra short flat bottom hydrocyclone 300c can obtain a lower circulating load while having

a lower classification efficiency compared to a standard flat bottom hydrocyclone 300a. If

the grinding throughput is causing a delay in the mineral processing system 10, a short or

extra short flat bottom hydrocyclone (300b and 300c respectively) may be the most

appropriate configuration of a flat bottom hydrocyclone for a primary grinding circuit. This

will increase the efficiencies of the system 10 but, as will be appreciated, the system 10 as

a whole needs to be considered in evaluating and adopting one of the hydrocyclones 300.

[00186] In this specification, adjectives such as left and right, top and bottom, hot and

cold, first and second, and the like may be used to distinguish one element or action from another element or action without necessarily requiring or implying any actual such relationship or order. Where context permits, reference to a component, an integer or step

(or the alike) is not to be construed as being limited to only one of that component, integer,

or step, but rather could be one or more of that component, integer or step.

In specification,

[00187] In this

[00187] this specification, the terms the terms 'comprises', 'comprises', 'comprising', 'comprising', 'includes', 'includes', 'including', 'including',

or similar terms are intended to mean a non-exclusive inclusion, such that a method,

system or apparatus that comprises a list of elements does not include those elements

solely, but may well include other elements not listed.

[00188] The above description relating to embodiments of the present disclosure is

provided for purposes of description to one of ordinary skill in the related art. It is not

intended to be exhaustive or to limit the disclosure to a single disclosed embodiment. As

mentioned above, numerous alternatives and variations to the present disclosure will be

apparent to those skilled in the art from the above teaching. Accordingly, while some

alternative embodiments have been discussed specifically, other embodiments will be

apparent apparent or or relatively relatively easily easily developed developed by by those those of of ordinary ordinary skill skill in in the the art. art. The The present present

disclosure is intended to embrace all modifications, alternatives, and variations that have

been discussed herein, and other embodiments that fall within the spirit and scope of the

above description.

Item List:

Item No Item

10i 10i Mineral Processing System

100 New Feed Material

100' Feed Material

150 Processed Material

200i Grinding Apparatus

210 Conventional Feed Inlet

230 Conventional Overflow Pathway

240 Conventional Underflow Pathway

250 Conical Section

260 Conventional Spigot

270 Cylindrical Section

280 Conventional Vortex Finder

300 Flat Bottom Hydrocyclone

310 Feed Inlet

320 Body 330 Overflow Pathway

340 Underflow

350 Section

360 Flat Surface

370 Spigot

380 Vortex Finder

400 Mechanical Screen

500 500 Return Pathway

600 Slurry Hopper

700 Pebble Crusher

750 Bin Bin

780 Feeder

800 Feed Pump

Claims

Claims: 07 Aug 2025

1. A hydrocyclone comprising:

an inlet in communication with the chamber, the inlet configured to receive a processed material from a grinding apparatus; 2021466603

a second outlet associated with the chamber, the second outlet configured to convey a second stream from the hydrocyclone,

wherein at least part of a surface forming the chamber is substantially flat to cause a directional change in the processed material present in the chamber.

2. The hydrocyclone of claim 1, wherein the processed material includes magnetite ore.

3. The hydrocyclone of claim 1 or 2, wherein the surface is approximately located at the bottom of the chamber.

4. The hydrocyclone of any one of claims 1 to 3, the hydrocyclone produces a separation due to the directional change of the processed material against the surface of the chamber whereby: i) particles above approximately 300μm are generally directed towards the first outlet; and ii) particles below approximately 300μm are generally directed to the second outlet.

5. The hydrocyclone of claim 4, wherein particles above approximately 0μm to 200μm are generally directed to the second outlet.

6. The hydrocyclone of any one of the preceding claims, wherein the classification efficiency is above approximately 40%.

7. The hydrocyclone of claim 6, wherein the particle size associated with the classification efficiency is approximately 106 μm.

8. The hydrocyclone of any one of the preceding claims, wherein the surface is orientated transversely to one or more further walls of the chamber; and/or wherein the directional change includes a substantially perpendicular directional change.

9. The hydrocyclone of any one of the preceding claims, wherein a density of the processed material varies from approximately 30% to 60% solid material.

10. The hydrocyclone of any one of the preceding claims, wherein a working pressure of 07 Aug 2025

the processed material is between approximately 40 to 90 kPa.

11. The hydrocyclone of any one of the preceding claims, wherein the hydrocyclone is configured to process up to approximately 750 to 900 cubic metres per hour.

12. A mineral processing system including:

a grinding apparatus configured to receive a feed material and output a processed material; and 2021466603

one or more hydrocyclones according to any one of claims 1 to 11.

13. The mineral processing system of claim 12, wherein the feed material to the grinding apparatus includes new feed material that is unprocessed by the grinding apparatus and is fed above 1250 wet metric tons/hour.

14. The mineral processing system of claim 12 or 13, wherein the grinding apparatus and the one or more hydrocyclones are arranged in a feedback loop, optionally, with a mechanical screen, and, further optionally, wherein a hopper is arranged in the feedback loop between the mechanical screen and the one or more hydrocyclones.

15. The mineral processing system of any one of claims 12 to 14, wherein the grinding apparatus is an autogenous mill or a semi-autogenous mill.

16. The mineral processing system of claim 15, wherein the grinding apparatus is configured to accept a feed material with a P80 of 100 to 200 mm.

17. The mineral processing system of any one of claims 12 to 14, wherein the grinding apparatus is a ball mill.

18. The mineral processing system of claim 17, wherein the grinding apparatus is configured to accept a feed material with a P80 of 10-20 mm.

19. A method for processing minerals is disclosed, the method including the steps of:

conveying the processed material to one or more hydrocyclones, each hydrocyclone in the form of any one of claims 1 to 11;

separating components from the processed material into a first stream and a second stream using one or more hydrocyclones, wherein part of the material has a directional change to separate the streams;

returning the first stream the grinding apparatus; and conveying the second stream downstream for further processing. 07 Aug 2025

20. The method of claim 19, wherein the method further includes the steps of:

the processed material entering a body of the one or more hydrocyclones, the body having a chamber, wherein at least part of a surface of the chamber is substantially flat to cause the directional change in the processed material present in the chamber;

the processed material undergo the directional change when coming into contact with the surface; and, optionally, 2021466603

wherein the directional change provides a coarser material being directed to the first stream compared to the second stream.