JP7140225B2 - Rotating sieve device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rotary sieve device, and more particularly to a trommel attached to a drum washer for sieving nickel raw material ore used in an HPAL plant.

In recent years, as a hydrometallurgy method for nickel oxide ore, a high pressure acid leach method using sulfuric acid has attracted attention. Unlike the conventional pyrometallurgical method, which is a general nickel oxide ore smelting method, this method does not include dry processes such as reduction and drying processes, and consists of a consistent wet process. advantageous in terms of It also has the advantage of being able to obtain a nickel-containing sulfide (hereinafter also referred to as "nickel sulfide") with a nickel grade improved to about 50% by mass.

In an HPAL plant that uses low-grade nickel ore, nickel raw material ore, which is a raw material, is transported and supplied from a mine. This contains large-grained ore, which becomes an obstacle when pumping ore is used. In addition, the nickel grade of large-grained ore is low, and leaching occurs only on the surface of this ore, so it is necessary to remove nickel at a low leaching rate. Therefore, in the nickel raw material preparation process for preparing the nickel raw material ore in the HPAL plant, washing and sieving equipment are installed in order to remove the large grain size ore.

A drum washer consisting of a drum and a trommel for removing large-sized ore is used as a washing and screening device. The trommel is equipped with a cylindrical sieve screen that is installed horizontally (with the axis being horizontal or nearly horizontally inclined), and by rotating the sieve screen around the axis, the material to be treated that is put into the sieve screen is This is an apparatus for classifying objects (processing for classifying objects of various sizes according to their sizes). One of the uses of such a trommel is to classify nickel oxide ore.

For example, in order to prevent a significant decrease in the efficiency of crushing and classifying to prepare nickel raw material ore, on the same circumference of the cross section perpendicular to the trommel rotation axis on the inner surface of the trommel, a predetermined requirement Satisfactory projections have been proposed (see Patent Document 1).

JP 2009-173967 A

However, when the trommel described in the above-mentioned Patent Document 1 is used in an HPAL plant, the large-grained ore contained in the ore slurry is lifted by being discharged from the drum or rotated, and the large-grained ore that falls during rotation The impact of the trommel wears or breaks the trommel screen, requiring repair during operation. Repairs during operation may affect the operating rate of subsequent equipment, and may reduce production efficiency.

In order to avoid such a situation, a trommel screen using general expanded metal has been used, but if damage is confirmed by constant inspection during operation, the equipment will be stopped each time. It had to be stopped frequently due to its short service life.

Therefore, the present invention has been proposed in view of such circumstances, and provides a new and improved rotary sieve device capable of extending the life while maintaining the sieving performance of nickel raw material ore. intended to provide

That is, in order to achieve the above object, in one aspect of the present invention, there is provided a rotary sieve apparatus provided with a truncated conical tubular or cylindrical screen rotatable about an axis, wherein the screen is used for classifying The screen has an introduction side into which objects are introduced and a discharge side into which the objects to be classified remaining after classification are discharged, wherein the screen is provided with a metal grating on the introduction side, and the metal grating is disposed on the discharge side. A grid-like resin screen is provided at the tip of the side so as to extend further from the discharge side.

In one aspect of the present invention, it is preferable that the metal grating extends to a range of 0.25 to 0.5 times the length of the screen in the axial direction.

In one aspect of the present invention, preferably, a punching metal is further provided along the outer peripheral surface of the resin screen, and the opening of the punching metal is larger than the opening of the resin screen.

In one aspect of the present invention, the metal grating preferably has a thickness of at least 5 mm or more.

In one aspect of the present invention, the metal grating is preferably made of carbon steel or stainless steel.

In one aspect of the present invention, the resin screen is preferably made of polyurethane resin.

In one aspect of the invention, the drum washer may be used to screen nickel raw ore in a hydrometallurgical plant.

ADVANTAGE OF THE INVENTION According to this invention, the sieving performance of the nickel raw material ore used in a HPAL plant can be maintained, and a lifetime can be extended.

BRIEF DESCRIPTION OF THE DRAWINGS It is process drawing of the hydrometallurgical method by the high pressure acid leaching method of a nickel oxide ore. It is a schematic explanatory drawing of a drum washer. It is a schematic explanatory drawing of the trommel which concerns on 1st Embodiment. FIG. 4 is a schematic cross-sectional view showing a punching metal provided outside a resin screen provided in the trommel according to the first embodiment; It is a schematic explanatory drawing of the trommel which concerns on 2nd Embodiment. 1 is a schematic illustration of a trommel based on Example 1. FIG.

Preferred embodiments of the present invention will be described in detail below. It should be noted that the present embodiment described below does not unduly limit the content of the present invention described in the claims, and all of the configurations described in the present embodiment are essential as means for solving the present invention. not necessarily.

[1. Overview]
A nickel oxide ore hydrometallurgical process is a smelting process in which nickel is leached and recovered from nickel oxide ore using, for example, high pressure acid leaching (HPAL).

FIG. 1 is a process diagram of a hydrometallurgical method by high-pressure acid leaching of nickel oxide ore. As shown in FIG. 1, the nickel oxide ore hydrometallurgical process includes an ore slurrying step S1 of slurrying the nickel oxide ore and an ore slurry concentration step of removing water contained in the ore slurry to concentrate the ore components. S2, a leaching step S3 in which sulfuric acid is added to the produced ore slurry and subjected to leaching treatment under high temperature and high pressure, and the residue (leaching residue) is separated while washing the obtained leaching slurry in multiple stages to remove impurity elements together with nickel. Limestone is added to the leachate as a neutralizing agent to adjust the pH of the leachate to separate the neutralized sediment containing impurity elements, and the final neutralization solution containing nickel is obtained. and a sulfurization step S6 of adding a sulfurizing agent to the final solution of neutralization to generate a sulfide containing nickel (nickel sulfide).

Furthermore, this hydrometallurgical process has a final neutralization step S7 for recovering and detoxifying the leach residue separated in the solid-liquid separation step S4 and the poor liquid discharged in the sulfurization step S6. This final neutralization step S7 includes a first stage neutralization treatment (first final neutralization step) using limestone as a neutralizing agent and a second stage neutralization treatment using slaked lime as a neutralizing agent ( Second final neutralization step). By performing such a two-stage neutralization treatment, a neutralization treatment residue is generated and stored in the tailing dam (tailing residue).

In the HPAL plant, in the process of obtaining ore slurry from the nickel raw material ore in the ore slurrying step S1, a cleaning device is installed to remove large grain size ore. Since the ore is acid-leached in the above-described leaching step S3, the cleaning device has a function of sorting the nickel raw material ore. This washing apparatus is composed of a drum washer (drum-type washing machine) and a sieving machine. The drum washer has the function of increasing the quality of nickel in the ore slurry by washing the nickel raw material ore with water.

FIG. 2 is a schematic illustration of the drum washer. The drum washer 1 includes a drum 10 and a trommel 20, as shown in FIG. The drum 10 has a function of crushing and repulping (unraveling) the nickel oxide ore to obtain an ore slurry S. The recovery blade 11 has a function of raking up the ore contained in the ore slurry S from inside the drum 10 . The trommel 20 has a function of sieving the ore contained in the ore slurry S.

In the drum washer 1, water and nickel oxide ore are supplied from an inlet (not shown) provided on the inlet side (upstream side) of the drum 10, and the required nickel raw material ore is removed from the large grain size ore in the drum 10 with water. and sent to the trommel 20, which is a large classifier, and the screen of the trommel 20 removes the ore with a particle size of 25 mm or more contained in the ore slurry S. Further, a sieving machine arranged under the screen of the trommel 20 removes ores having a particle size of 1.4 mm or more contained in the ore slurry S that has passed through the screen.

Therefore, a large classifying device called a trommel 20 is installed on the outlet side (downstream side) of the drum 10 in order to screen the ore slurry S and the large-sized ore. The screen of the trommel 20 is a cylindrical or conical screen made of expanded metal, wire mesh, or resin. It is configured to be separable.

The ore slurry S sent out from the drum 10 overflows from a weir (not shown) installed near the connecting portion of the drum 10, and the ore contained in the ore slurry S is scooped up by the recovery blade 11 provided inside the drum 10. and transferred to the trommel 20. Here, since the recovery blade 11 is provided on the drum 10, the ore is scraped up from the system of the drum 10, so that the ore contained in the ore slurry is transferred from the drum 10 to the trommel 20 without delay. As a result, the ore slurry can be obtained with a stable ore content rate, and the large grain size ore is less likely to be retained in the drum 10, so that the drum 10 itself can be prevented from wearing, and the energy required to drive the drum 10 can be reduced. mitigated.

However, when the large particle size ore contained in the ore slurry S is transferred to the trommel 20 by the recovery blade 11, the large particle size ore falls onto the screen of the trommel 20, and the impact is very large, and the impact is very large. The wear and damage of the screen becomes noticeable at

Here, when the screen of the trommel 20 is broken, the ore having a large particle size is brought into the sieving machine in the subsequent stage, the load applied to the sieving machine is increased, and the sieving machine is easily damaged. If the sieving machine breaks down, large-sized ore clogs the narrow parts of the pumps and valves, blocking the flow path of the ore slurry. be done. In order to prevent breakage of the sieving machine and clogging of the flow path, if wear or breakage of the screen of the trommel 20 is confirmed, even if the HPAL plant is in operation, stop the equipment and repair the screen. It was necessary to perform and replace the equipment, which was a factor in lowering the operating rate of the equipment.

For example, all screens can be provided with thick metal gratings to reduce wear and tear of the screens. However, at the cost of securing the strength of the screen, the opening area for sieving is insufficient, and the raw material ore slurry is excessively discharged outside the trommel 20 system, and the weight of the equipment increases. driving becomes difficult. On the other hand, when all the screens are made of resin, they have a certain degree of impact resistance and abrasion resistance, but the strength of the resin screen itself is insufficient. The opening gradually widens and ores larger than the desired particle size cannot be excluded.

Therefore, the inventor of the present invention has proposed that, in order to maintain the screening performance of the screen of the trommel 20 attached to the drum washer 1 used when screening the nickel raw material ore used in the HPAL plant, the connecting portion with the drum 10 The inventors have found that the service life of the trommel 20 can be extended by providing a grid-like metal grating around the perimeter of the trommel 20, and completed the present invention.

[2. Trommel]
Next, the trommel according to this embodiment will be described with reference to the drawings.

[2-1. First Embodiment]
FIG. 3 is a schematic explanatory diagram of the trommel according to the first embodiment. As shown in FIG. 3, the trommel 100 according to the first embodiment is provided with a conical (truncated cone-shaped) screen 110 rotatable about its axis. The screen 110 has the function of sieving the ore transferred from the drum to a desired particle size. Since the screen 110 has a conical shape, the large particle size ore contained in the ore slurry transferred from the drum provided in the drum washer by the recovery blades rolls along the slope on the screen 110 and is discharged. Each component will be described below.

In the first embodiment, the screen 110 has a grid-like metal grating 111 extending along the axial direction from the connecting portion with the drum, and the extended tip of the metal grating 111 is A grid-like resin screen 112 is provided so as to extend along the axial direction. In addition, this metal grating 111 may be of an integrated structure, or may be of a plurality of divided structures. This segmented configuration is composed of multiple pieces of metal grating.

As a result, in the first embodiment, even if the large-diameter ore contained in the ore slurry transferred from the drum by the recovery blades drops directly onto the screen 110, the drop point hit first is impact-resistant. Since it becomes the area|region of the metal grating 111 which is high, the abrasion and damage by a direct fall are suppressed. After impacting the metal grating 111, even if the ore rolls further along the slope onto the resin screen 112, the impact is weaker than the initial impact. The screen 112 is restrained from wear and damage. In this way, the good sieving performance of the grid-like metal grating 111 and the grid-like resin screen 112 can be maintained. Therefore, the operation of the HPAL plant can be stably performed for a long period of time without stopping for repair or replacement of the screen 110 .

The metal grating 111 preferably extends in the range of 0.25 to 0.5 times the length of the screen 110 in the axial direction, and in the range of 0.3 to 0.4 times. It is even more preferable to have By setting such a range, while suppressing the energy required to drive the trommel 100, the drop point of the large grain size ore transferred from the drum is the area provided with the metal grating 111, so the impact due to collision is reduced. can also withstand
Therefore, the trommel 100 is not damaged in a short period of time during the operation of the HPAL plant, and the ore screening function of the trommel 100 can be maintained, and the life of the trommel 100 itself can be extended more reliably. .

If the metal grating 111 extends only less than 0.3 times, it is conceivable that the large grain ore transferred from the drum jumps over the metal grating 111 and falls onto the resin screen 112. At that time, the trommel 100 may be damaged in a short period of time. Especially when the metal grating 111 extends only to less than 0.25 times, in addition to the movement of the large-grained ore being raked up and ricocheted, the large-grained ore is piled on top of each other. There is also a risk of falling onto the resin screen 112 due to the collapsing motion. On the other hand, if the metal grating 111 extends more than 0.4 times, the range of the metal grating 111 on the screen 110 becomes large and requires much energy to rotate. In particular, when the metal grating 111 extends more than 0.5 times, if the trommel 100 has a shape (trumpet shape) that widens as the trommel 100 moves away from the drum side, the position ( A metal grating 111 (heavy compared to resin) is placed. As a result, it takes a particularly large amount of energy to rotate the trommel 100 because the moment of inertia is proportional to the square of the radius and proportional to the density.

The metal grating 111 is not particularly limited as long as it is made of metal, alloy, or the like, but is preferably made of carbon steel, stainless steel, or the like, which has excellent water resistance and impact resistance.

It is preferable that the thickness of the metal grating 111 is at least 5 mm or more. By setting the thickness to 5 mm or more, the metal grating 111 becomes strong and can extend its life, and it becomes easy to visually confirm the progress of wear. If the thickness is less than 5 mm, when the large grain size ore contained in the ore slurry falls and collides, the mesh opening of the lattice may expand beyond the desired range due to the impact.

In addition, as the grid-like metal grating 111, a grating having square holes is used, but the present invention is not limited to this. Even a metal grating 111 can be used without any problem.

In the first embodiment, reinforcing frames 120a and 120b are attached to reinforce the screen 110. FIG. Specifically, the reinforcing frame 120 a is attached so as to connect the metal grating 111 and the resin screen 112 . A reinforcement frame 120b is attached to the outer peripheral surface of the screen 110 along the longitudinal direction. Further, a reinforcing ring 121a is attached to the base end of the screen 110 (the end on the drum side), and a reinforcing ring 121b is attached to the tip of the screen 110 (the end opposite to the drum).

In addition, the metal grating 111 is configured in advance so as to be partitioned by a plurality of grating parts, and if the metal grating 111 is damaged or worn due to the operation of the HPAL plant, the entire metal grating 111 is replaced. Instead, only the part corresponding to the damaged area needs to be replaced. Therefore, there is no need to replace the entire surface like the conventional wire mesh screen, and the cost and labor can be minimized.

Although the resin screen 112 is not particularly limited, it is preferably made of one or more of polyurethane resin, polyester resin, nylon resin, and polyamide resin. More preferably.

Moreover, the thickness of the resin screen 112 is preferably a thickness that eliminates the step at the boundary with the metal grating 111, and if there is a step, it is preferably a thickness that is smaller than the diameter of the ore particles. . In particular, it is appropriate to have a thickness that results in a step of 25 mm or less. is changed so that the step is 25 mm or less.

The metal grating 111 and the resin screen 112 are desirably attached at the same angle in order to reduce the impact caused when the ore is transferred from the metal grating 111 to the resin screen 112 .

Further, in the first embodiment, the resin screen 112 is preferably provided with a reinforcing material. FIG. 4 is a schematic cross-sectional view in which punching metal is provided outside the resin screen provided in the trommel according to the first embodiment. In the first embodiment, a punching metal 113 is provided outside the resin screen 112 along the outer peripheral surface of the resin screen 112, as shown in FIG. Moreover, the opening W2 of the punching metal 113 is larger than the opening W1 of the resin screen 112 in order to ensure the ore screening function of the screen 110 .

As a result, after the large-grained ore transferred from the drum impacts the metal grating 111 by collision, even if the large-grained ore rolling along the slope impacts the resin screen 112 by collision, Since the impact is transmitted not only to the resin screen 112 but also to the punching metal 113, the punching metal 113 can reinforce the resin screen 112 and the resin screen 112 can withstand external impact. Thus, the perforated metal 113 has the function of the resin screen 112 as a reinforcing member. Therefore, the life of the trommel 100 can be more reliably maintained, and the ore screening function of the trommel 100 can be maintained.

[2-2. Second Embodiment]
FIG. 5 is a schematic explanatory diagram of the trommel according to the second embodiment. As shown in FIG. 5, the trommel 200 according to the second embodiment is provided with a cylindrical screen 210 rotatable about its axis. Reinforcement rings 221a and 221b are attached. Each component will be described below. In addition, the description of what overlaps with the first embodiment is omitted.

In the second embodiment, the screen 210 is provided with a grid-shaped metal grating 211 extending along the axial direction from the connecting portion with the drum, and the extended tip of the metal grating 211 is A grid-like resin screen 212 is provided so as to extend along the axial direction.

When the trommel 200 is used for a drum washer, the cylindrical screen 210 is horizontally connected to the drum outlet side, and the drum and the horizontal direction are inclined at a predetermined angle (for example, 1° to 20°). ). At this time, the large particle size ore contained in the ore slurry transported by raking up the drum provided in the drum washer with the collecting blade is discharged by rolling along the slope on the screen 210 .

[3. summary]
As described above, the trommels according to the first embodiment and the second embodiment are connected to the drum provided in the drum washer, and provided with a cylindrical screen rotatable about the axis. The screen has a grid-like metal grating extending along the axial direction from the connecting portion with the drum, and the tip of the extended metal grating extends along the axial direction. It is characterized by providing a grid-like resin screen.

As a result, by raking up the large-grained ore contained in the ore slurry with the recovery blades provided in the drum, the falling point of the large-grained ore transferred from the drum to the trommel is the area provided with the metal grating. As a result, the screen on the trommel can withstand strong impacts. Therefore, the life of the trommel itself can be extended without damaging the screen of the trommel in a short period of time during the operation of the HPAL plant. As a result, frequent shutdowns to repair or replace trommel screens are avoided. Further, a drum washer comprising a drum connected to a trommel is most suitable for sieving nickel raw material ore in a hydrometallurgical plant because it allows efficient operation of the HPAL plant with less frequent shutdowns.

The present invention will be described in more detail below using Examples and Comparative Examples, but the present invention is not limited to these Examples or Comparative Examples.

In an HPAL (high pressure acid leaching) plant, nickel oxide ore is slurried as a pretreatment for acid leaching of nickel oxide ore, using a drum washer with a trommel connected to the drum, under the conditions of Example 1 below. under the conditions of Comparative Example 1 below.

(Example 1)
FIG. 6 is a schematic illustration of a trommel based on Example 1. FIG. In Example 1, as shown in FIG. 6, the base end (drum side end) of the screen 310 of the conical trommel 300 where the ore discharged from the drum unit of the drum washer first drops. In consideration of impact resistance, the first row screen 311 on the side is a metal grating (width 800 mm) made of flat steel (horizontal length 24 mm × thickness 5.0 mm) arranged in a grid shape. × 1250 mm in horizontal length × 25 mm in thickness). The second-row screen 312 and the third-row screen 313 are provided with a urethane screen with a thickness of 30 mm (opening of 25 mm). I installed it and made it a double structure screen. Furthermore, reinforcing frames 320a and 320b and reinforcing rings 321a and 321b were attached to the screen, respectively. The first to third screens 311 to 313 are arranged at regular intervals. A urethane screen is a screen made of polyurethane.

As a result of operating the HPAL plant, as shown in Table 1, the time required for repair and the time required for replacement of the first row screen 311 were each one year after the start of use. In addition, the second-row screen 312 and the third-row screen 313 needed to be repaired 4 to 6 months after the start of use, and needed to be replaced 6 to 8 months after the start of use.

(Comparative example 1)
In Comparative Example 1, the operation was performed in the same manner as in Example 1, except that the first to third row screens were changed to 30 mm thick urethane screens (opening of 25 mm).

As a result of the operation, as shown in Table 2, the time required for repair of the first row screen was 1 to 2 months after the start of use, and the time required for replacement was 2 to 4 months after the start of use. In addition, the second-row screen and the third-row screen needed to be repaired 2 to 4 months after the start of use, and needed to be replaced 4 to 6 months after the start of use.

(Consideration based on Examples)
Comparing Tables 1 and 2, Example 1 requires less screen repair or replacement than Comparative Example 1, which means that the trommel can be used for a long period of time. As a result, the operation rate of this facility based on Example 1 was improved, and stable operation became possible. In addition, even in the operation after implementation, only ore with a size of 25 mm or less was observed on the sieve, confirming that ore slurry containing ore with a particle size narrower than the screen opening was recovered. rice field.

In this way, the metal grating used in Comparative Example 1 was provided so as to extend along the axis from the connection portion (base end of the screen) with the drum used in Example 1. It was confirmed that the time required for repair and replacement was longer than the Trommel, which has a urethane screen on the entire screen. That is, it is considered that the trommel used in Example 1 was able to extend its life in the operation of the HPAL plant due to the provision of the metal grating on the entrance side of the trommel.

1 drum washer, 10 drum, 11 recovery blade, 20 trommel, 100 trommel, 110 screen, 111 metal grating, 112 resin screen, 113 punching metal, 120a, 120b reinforcement frame, 121a, 121b reinforcement ring, 200 trommel, 210 Screen 211 Metal grating 212 Resin screen 220a, 220b Reinforcement frame 221a, 221b Reinforcement ring 300 Trommel 310 Screen 311 First row screen 312 Second row screen 313 Third row screen , 320a, 320b reinforcement frame, 321a, 321b reinforcement ring, S ore slurry

Claims (7)

A rotary sieve device provided with a frusto-conical tubular or cylindrical screen rotatable about its axis,
The screen has an introduction side into which the objects to be classified are introduced and a discharge side from which the objects to be classified remaining after classification are discharged,
The screen has a metal grating on the introduction side,
A rotary sieve apparatus, wherein a grid-like resin screen is provided at the tip of the metal grating on the discharge side so as to extend further from the discharge side. 2. The rotary sieve apparatus according to claim 1, wherein said metal grating extends from 0.25 to 0.5 times the length of said screen in said axial direction. A punching metal is further provided along the outer peripheral surface of the resin screen,
3. The rotary sieve apparatus according to claim 1, wherein the opening of said punching metal is larger than the opening of said resin screen. 4. The rotary sieve apparatus according to any one of claims 1 to 3, wherein said metal grating has a thickness of at least 5 mm or more. 5. The rotary sieve apparatus according to any one of claims 1 to 4 , wherein said metal grating is made of carbon steel or stainless steel. 6. The rotary sieve apparatus according to any one of claims 1 to 5 , wherein said resin screen is made of polyurethane resin. 7. The rotary sieve apparatus according to any one of claims 1 to 6 , wherein the rotary sieve apparatus is connected to a drum washer for use in screening nickel raw material ore in a hydrometallurgical plant.

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