JPS5850301B2 - Heat-resistant heat-resistant heat treatment method for the medical equipment of the - Google Patents

Description

DETAILED DESCRIPTION OF THE PRESENTINESS The present invention relates to the beneficiation of non-ferrous matter, i.e. non-ferrous metal-containing sulfide materials, and more particularly to the thermal beneficiation of non-ferrous metals contained in ferrous sulfide materials.

The most common nickel-bearing ores in sulfide ores are bentlandite and pyrrhotite.

Bendtlandite corresponds to the formula (Nl t Fe) g SB, which contains about 34 mg of nickel and is easily processed for nickel recovery.

Pyrrhotite is not properly classified as a nickel ore, but is an iron-deficient sulfide with the formula F eX S X+ .

(X is an integer of 1 or greater) in which a small amount of nickel is substituted for iron.

In most cases, the nickel content of pyrrhotite rarely exceeds about 2φ, so that large amounts of pyrrhotite must be processed to recover relatively small amounts of nickel.

After mining, the nickel-bearing sulfide ore is crushed and then beneficiated to produce the amount of ore required for processing to recover nickel.

Most commonly, the crushed ore is subjected to comprehensive flotation to produce a crude concentrate which contains most of the nickel in the ore as bentrandite and most of the copper as chalcopyrite, and crude tailings which contain most of the gangue and pyrrhotite.

When copper is present, the combined concentrate can be selectively flotated to give separate nickel and copper concentrates which can be processed individually to recover the nickel and copper.

The tailings are further processed to produce a scavenger concentrate, which is further processed to produce an iron concentrate based on nickel-bearing pyrrhotite, generally having a nickel content of 1.5φ or less.

The scavenger and/or iron concentrate can be combined with the nickel concentrate for further processing to recover the nickel content.

However, it is preferred, where possible, to process the pyrrhotite separately to recover the nickel content and produce iron ore.

In conventional smelting processes, iron is slowly oxidized in roasters, reverberatory furnaces and converters so that the iron oxide can be removed by slagging in the reverberatory furnaces and converters.

All of these operations almost always produce waste gases that are very low in sulfur dioxide, making recovery of sulfur dioxide from the waste gases difficult and prohibitively expensive.

Currently, the scavengers and/or iron concentrate are processed separately to usefully recover the nickel, iron and sulfur.

Nickel-containing pyrrhotite is roasted in a fluidized bed to produce low-sulfur calcine and a sufficient amount of sulfur dioxide.
It produces waste gas and enables the recovery of sulfuric acid from the waste gas.

Since the amount of sulfur in iron concentrate is generally about 20 times the amount of nickel, if sulfur dioxide is recovered, a large amount of sulfuric acid is produced.

Although the production of sulfuric acid would help remove a large amount of sulfur dioxide emissions from the process, there is already an oversupply of acid within a reasonable distance of the smelter to shipping, making it uneconomical to expand.

Reduction of sulfur dioxide to storable elemental sulfur is also an expensive method of reducing sulfur dioxide emissions from a process.

High temperature calcin is selectively reduced to reduce most of the nickel and only a very controlled amount of iron.

Nickel and other non-ferrous metals are removed by leaching the selectively reduced ore with an aerated ammoniacal ammonium carbonate solution and the leach solids, after suitable washing, are pelletized and sintered to produce high quality iron oxide pellets.

The value-containing leachate is treated to recover the nickel.

As can be seen from the foregoing brief description, whether the scavenger or iron flotation concentrate is combined with the nickel flotation concentrate or processed separately, the processing of large quantities of high sulfur pyrrhotite to recover relatively small amounts of nickel requires multiple operations involving large capital expenditures for roasting, smelting and conversion equipment and large operating costs, including fuels and other reagents.

Attempts have been made to overcome the aforementioned difficulties and other drawbacks, but to the applicant's knowledge, none of them have been entirely successful in commercial implementation on an industrial scale.

The non-ferrous metals contained in the iron sulfide ore are extracted by treating the sulfate ore with a special agent at a controlled temperature and in a specific controlled atmosphere, resulting in metallic iron with concentrated non-ferrous metals.
It was then discovered that the metallic iron could be separated from the bulk of the iron sulfide ore to recover the non-ferrous metals.

In accordance with the present invention, an intimate mixture of granular iron-based sulfide ore containing non-ferrous metals, granular iron oxide or metallic iron and, if iron oxide is present, granular reducing agent is agglomerated, the mixture is heated to 800-1000°C in a non-oxidizing atmosphere for metallic iron for a time sufficient to reduce the iron oxide to metallic iron and concentrate most of the non-ferrous metals in the iron, then the mixture is cooled in a non-oxidizing atmosphere and the cooled agglomerates are crushed,
The present invention provides a method for beneficiating non-ferrous metals contained in iron-based sulfide ore, which comprises separating metallic iron from the iron-based sulfide ore to obtain a non-ferrous metal concentrate.

Generally, military methods involve beneficiating the nickel content of nickel-bearing ferrous sulfide ores to substantially eliminate the production of sulfur dioxide and to provide a metallic iron concentrate which is easily separated from the ferrous sulfide ores.

Typically, most of the sulfur in the sulfide ore remains as sulfide during processing, resulting in a disposable product low in non-ferrous metals at the end of the process.

In one embodiment, an intimate mixture of finely divided non-ferrous metal-containing iron-based sulfide ore, iron oxide and a suitable reducing agent is agglomerated.

The nodules are heated to 800-1000°C in a non-oxidizing atmosphere for metallic iron and held there to reduce the iron oxide to metallic iron and concentrate the non-ferrous metals from the sulfide ore into metallic iron.

Metallic iron, which is enriched with non-ferrous metals, is separated from the iron sulfide ore after the nodules are cooled and crushed.

More specifically, the nickel content contained in the nickel-containing iron-based sulfide ore can be concentrated.

A dense mixture of finely divided nickel-bearing iron-based sulfide ore, iron oxide and a suitable reducing agent is agglomerated and heated to reduce the iron oxide to metallic iron, causing the nickel to diffuse from the sulfide ore into the metallic iron.

Non-ferrous metals that can be recovered include nickel and cobalt, but the invention is not limited thereto.

Examples of non-ferrous metal-containing iron-based sulfide ores are hematite and bentlandite, but the present invention is not limited thereto.

The method according to the present invention can be used to concentrate non-ferrous metals contained in the aforementioned iron-based sulfide ores, but the following description is limited to the concentration of nickel contained in porcelain iron ore in order to facilitate the description of the present invention, but it will be readily apparent to those skilled in the art that other non-ferrous metals can be similarly concentrated.

Bentlandite, the magnet that contains most of the nickel of a nickel-bearing sulfide ore, can be effectively treated by known means.

The nickel-bearing sulphide ore can be crushed to liberate it from the rock, and the bentlandite can be recovered separately by flotation.

In most cases the ore is crushed to at least 75% minus 65 mesh, and preferably 85% minus 65 mesh or better.

Please note that the mesh dimensions mentioned here are U, S
, based on standard screen dimensions.

After crushing, the crushed ore is subjected to an integrated flotation process to produce an integrated concentrate containing substantially all the bentlandite and chalcopyrite, while the tailings contain the less floatable porphyrite as well as rock.

The crude tailings are subjected to a second flotation process to obtain a nucavenger concentrate containing substantially all of the porphyrite.

The scavenger concentrate is then reground to a particle size of at least 80 mm minus 200 mesh, preferably 90 mm minus 200 mesh, and rewashed to remove excess copper-nickel content.

Nickel-containing pyrite can be mixed with metallic iron to extract nickel, but a portion of the pyrite concentrate can be roasted to produce calcine with a sulfur content of about 5% or less.
It is then advantageous to form a mixture of the residual porcelain iron concentrate, calzine and a reducing agent and to heat the mixture to between 800 and 970°C to form metallic iron in situ.

Sufficient pyrrhotite is roasted to reduce the pyrrhotite to pyrrhotite ratio to 0.
It is advantageous to have a ratio of 15:1 to 5:1.

One advantage that arises from the use of roasted hematite is that nickel associated with the roasted hematite is also recovered in the concentrate.

Of course, if a suitable iron oxide material is available it may be substituted for the roasted hematite in the nodule feed.

Also, if suitable metallic iron powder is available it can be used in place of iron oxide plus reducing agent.

Similarly, the desired metallic phase can be produced in situ by substituting one molar equivalent of an alkali or alkaline earth oxide for the iron oxide.

This oxide is advantageously added in the form of calcium oxide.

When a mixture of hematite and roasted hematite is used to form metallic iron in situ, it is advantageous to incorporate a solid reducing agent into the mixture to provide high reduction capacity and thereby improved reduction kinetics.

If a solid reducing agent is added to the mixture, at least 80%
It is effectively added in granular form having a particle size of minus 65 mesh, and more preferably 80% minus 100 mesh.

Examples of particulate reducing agents are ground coke, charcoal or coal.

Whatever the form of the reducing agent, it is generally added to the iron ore mixture in an amount of from 20 to 70 ml of calcin, and more preferably from 25 to 50 ml of calcin.

Said amount of reducing agent ensures complete reduction of the roasted hematite, while minimizing loss of reducing agent to the hematite during cooling and separation of the metallic iron concentrate.

Although the mixture of hematite, calzin and reducing agent can be heated to reaction temperatures as a mixture of finely divided components, it is advantageous to agglomerate the mixture to minimize problems with sticking in the furnace and to maintain good solid-solid contact between the metal or reduced calzin and the hematite.

The mixture can be agglomerated by known means, such as pelletizing or briquetting.

The nickel content of the pyrrhotite is 800 to 100% by weight, whether the mixture is added as metallic iron or produced in situ.
It can be concentrated in metallic iron by heating to a temperature of 000°C, preferably 850 to 925°C.

When the mixture consists of hematite, calcin, and a reducing agent, such heating is effective not only to promote the diffusion of nickel into the iron metal, but also to promote the reduction of calcin.

At higher temperatures, the iron ore oxide mixture approaches its initial melting temperature, so care must be taken to avoid problems associated with sticking and excessive agglomeration.

At temperatures below those within the aforementioned ranges, the reduction and diffusion rates become so slow that the process quickly becomes uneconomical.

Heating of the calcined iron, hematite and reducing agent is carried out in a neutral or slightly reducing atmosphere to avoid oxidation of the reduced metallic iron.

Oxidized iron exhibits very limited solubility for nickel.

In most cases, the mixture has a CO:CO ratio of 1:2 to 2:1,
Most preferably, the mixture is heated to and maintained at the aforementioned temperature in an atmosphere having a reducing power of 1:1.5 to 1.5:1.

When a mixture is formed from calcite and hematite within the size ranges set forth above and the mixture is held at a temperature of 800 to 1000° C., most of the nickel associated with the hematite is concentrated into metallic iron in 10 to 120 minutes.

During heating times within the aforementioned ranges, substantially all of the nickel associated with the hematite, e.g., at least 70%, is diffused into the metallic iron.

Once substantially all of the nickel associated with the hematite has diffused into the metallic iron, the mixture is cooled without oxidizing the metallic iron concentrate.

In most cases, cooling rates below 100° C./min have little effect on the nickel recovery achieved by the magnetic field.

Physical separation of the metal alloy from the processed charge generally requires crushing the cooled mixture to liberate the metal base.

Because the heat treatment is conducted at a temperature below the initial melting point of the hematite and metallic iron, and because the heat treatment lasts for a relatively short period of time, the cooled mixture is easily ground to a fine particle size by conventional grinding techniques.

Best results are obtained by grinding the cooled mixture to a particle size of at least 80 minus 200 mesh and most preferably 95 minus 200 mesh.

The nickel enriched metal alloy is separated from the crushed mixture of iron sulfide and metal alloy by magnetic separation.

The metal alloy is magnetic, but the remaining iron sulfide is non-magnetic, allowing the concentrate to be recovered by conventional magnetic separation techniques.

As previously mentioned, it is preferred to agglomerate the mixture of hematite and calzine or metallic iron to avoid problems associated with sticking when the mixture is heated to temperatures within the aforementioned ranges.

It has been found that the process can be carried out in a rotary furnace without significant sticking problems if the temperature is kept below 900°C.

When using a rotary hearth furnace or a moving belt furnace where the nodular material does not move relative to the furnace, the use of higher temperatures is practical.

The process according to the invention can therefore be carried out in many different types of furnaces commonly used, subject to the temperature limitations set forth above.

In order that this invention may be better understood by those skilled in the art, the following examples are given.

Example I Three samples of nickel-bearing porcelain iron ore ground to a particle size of 90% minus 200 mesh containing approximately 1.25% nickel were prepared.
Part of the same pyrite mixed with 1 part of Calzin (i.e. 850 parts of the same pyrite mixed with 1 part of
(Roasted at 0.5°C to a sulfur content of 0.2φ) and 0.
It was mixed with 7 parts of finely ground bituminous coal.

The mixture is pressed to form a cassia briquette of about 2CrL x 2C x 1 cm and dried in a slightly reducing atmosphere (9
, 5% carbon dioxide, 5% water vapor, 9.5% carbon monoxide,
The mixture was heated at 870° C. in an atmosphere of 9.5% hydrogen and 66.5% nitrogen for 24 hours.

After this heat treatment, the mixture is cooled in a non-oxidizing atmosphere and pulverized in a wet pebble mill to a size of 95φ minus 325 mesh.
Wet magnetic separation was performed at 2800 Gauss.

The results of this test are shown in Table 1.

As can be seen from the results in Table 1, 89% of the nickel associated with the porcelain ore and calzine is shown to result in a magnetic concentrate containing 83φ nickel in the magnetic fraction.

Also, as can be seen from Table II, the non-magnetic portion of the mixture, encompassing the 87.3φ portion, contained only 0.15 μm of nickel.

Thus, the amount of material that must be processed to ultimately recover the nickel content of the original porphyroblastic ore is only four times that of the original mass.

Also, as can be seen from Table 1, the non-magnetic tailings fraction contained 96% of the sulfur present in the briquette mixture, and the magnetic fraction, which contained the nickel to be recovered by further processing, contained less than 4% sulfur.

Example: 90 minus 2 grain size containing approximately 0.82% nickel
3 parts of nickel-containing pyrite ground to 0.00 mesh was mixed with 1 part of Calzin (i.e., the same pyrite was mixed at 850° C.
roasted at 0.7 to a sulfur content of 0.2%
The coal was mixed with part of finely ground bituminous coal.

This mixture was pressed to about 3 cIrL x 2 cRl x 1
The briquettes were made into cylindrical briquettes of 1.5 ml of CrFL, and the mixture was placed in a slightly reducing atmosphere (9.5% carbon dioxide, 5.0% water vapor, 9.5% water vapor, 1 ...
87 in (carbon oxide, 9.5-dihydrogen and 66.5 mm nitrogen)
Heated at 0° C. for 9 hours.

The heat treated charge was cooled in a non-oxidizing atmosphere, ground in a wet pebble mill to 95 minus 325 mesh, and subjected to wet magnetic separation at 2000 gauss.

The results of this test are shown in Table II.

As can be seen from the results in Table II, it is shown that the result is a magnetic concentrate containing nickel associated with the pyrite in the calcined mixture.

Also, as can be seen from Table II, the non-magnetic portion, which comprises 87.2% of the mixture, contained only 0.13% nickel.

Thus, the amount of material that must be processed to ultimately recover the nickel content of the original porphyroar ore is only four times that of the original mass.

Example 1 Particle size 90 minus 20 containing approximately 1.25% nickel
Six parts of nickel-containing porcelain iron ore concentrate, crushed to 0.0 mesh, was mixed with 1.1 parts of lime (Cab) and 1.1 parts of finely ground bituminous coal.

This mixture is pressed to about 3crfL x 2crrL x I
CrIt cylindrical briquettes were prepared and heated for 90 min in a slightly reducing atmosphere (9.7% carbon dioxide, 7.1φ steam, 9.6% carbon monoxide, 6.3% hydrogen and 67.3% nitrogen).
Heated at 0° C. for 72 hours.

After this heat treatment, the charge was cooled in a non-oxidizing atmosphere, ground in a wet pebble mill to 95% minus 325 mesh, and subjected to magnetic separation at 2800 gauss.

The results of this test (shown in Table II) show that 79.9% of the nickel associated with the iron ore is present in the magnetic fraction containing 5.80% nickel.

The non-magnetic portion, which comprised 84.4% of the mixture, contained only 0.27% nickel.

Therefore, the amount of material that needs to be processed to ultimately recover the nickel contained in the original porphyroblast is only a small fraction of the original mass.

Example: Three parts of nickel sulfide concentrate crushed to a particle size of 901% minus 200 mesh containing approximately 8.4% nickel are mixed with 0.
0.7 parts fine iron powder and 0.15 parts fine bituminous coal.

This mixture was pressed to approximately 3α x 2CrL x 1Cr
The briquettes were then fired in a slightly reducing atmosphere (9
, 5.0% carbon dioxide, 5.0% water vapor, 9.5% carbon monoxide, 9.5% hydrogen and 66.5% nitrogen) at 815°C.
The mixture was heated at RT for 1 hour.

After this treatment, the charge is cooled in a non-oxidizing atmosphere and then crushed in a wet pebble mill to 95% minus 325 mesh.
The mixture was subjected to wet magnetic separation at 2800 Gauss.

According to the results shown in Table 3, the nickel (7) 90.4% contained in the feedstock had an analytical value of 23.
5. Yields nickel-rich concentrate.

The non-magnetic portion of the mixture, which made up 74.2%, contained only 0.87% nickel.

This fraction could be treated by any of the methods described in Example 1. It or 2 to recover substantially all of the nickel content.

Example: A particle size of 90% minus 2 containing approximately 8.4% nickel.
Three parts of nickel sulfide concentrate crushed to 0.00 mesh were mixed with one part of Calzin (0.82φ nickel pyrrhotite roasted at 850° C. to give a sulfur content of 0.2%) and 0.6 parts of fine bituminous coal.

This mixture was pressed to approximately 3CIrL x 2CIrL x I
The CrIL columnar briquettes were placed in a slightly reducing atmosphere (9.7% carbon dioxide, 7.1% water vapor, 9.6%-
8 in 100% CO, 6.3% H2 and 67.3% N2
Heated at 15° C. for 1 hour.

After this treatment, the mixture was cooled in a non-oxidizing atmosphere and pulverized in a wet pebble mill to 95 mm minus 325 mesh.
Wet magnetic separation was performed at 2800 Gauss.

The results of this test, shown in Table V, show that the 82.4 ppm of nickel contained in the original feed gave an analysis of 29.6 ppm of nickel in the magnetic fraction.

The non-magnetic portion made up 81.6% of the mixture and contained 1.42% nickel.

This portion could be treated by any of the methods described in Examples I, II or III to recover substantially all of the nickel content.

Example: One part of nickel-containing porphyroblastic iron ore, crushed to a particle size of 90 mm minus 200 mesh containing approximately 1.25% nickel, was mixed with 0.6 parts of tailings from a leaching process (39.5% FeO(OH)).
The mixture was mixed with 0.3 parts of fine bituminous coal (containing 0.18 parts iron, 0.18 parts nickel, 4.3 parts sulfate, and the remainder rock).

This mixture was pressed to about 3 crrL x 2 crrL x 1
The briquettes were made into cylindrical briquettes of cIrL and were heated for 9 h in a slightly reducing atmosphere (9.7% carbon dioxide, 7.1% water vapor, 9.6% carbon monoxide, 6.3% hydrogen and 67.3% nitrogen).
Heated at 00°C for 4 hours.

After this heat treatment the charge was cooled in a non-oxidizing atmosphere, ground in a wet Pefluer to 95° minus 325 mesh and subjected to wet magnetic separation at 2800 Gauss.

The results of this test, shown in Table 1, showed that 83.3% of the nickel associated with the pyrite and tailings had an assay of 4.5.
It is in the magnetic portion which is 5% nickel.

The non-magnetic portion, which comprised 85.1% of the mixture, contained only 0.16% nickel.

Therefore, the amount of material that must be processed to ultimately recover the nickel content of the porphyroblastic ore and tailings is only 7/1 of the original nodules.

Example: 1.25φ nickel pyrrhotite, 3 parts, 80 parts minus 20
1 part of calcined porcelain ore (85% in air) was crushed to 0.0 mesh.
Roasted at 0°C to reduce sulfur levels to 0.2% or less)
and 0.6 to 0.7 parts of fine bituminous coal.

Eight such mixtures were compressed to approximately 3 × 2 crfL × 100 ml.
The ICIrL columnar briquettes were individually placed in a slightly reducing atmosphere (9.7% carbon dioxide, 7.1% water vapor, 9
The materials were treated in a nitrogen atmosphere (6.6% carbon dioxide, 6.3% hydrogen and 67.3% nitrogen) at various furnace temperatures ranging from 814 to 1036°C.

Treatment times were typically 20 minutes.

The products of treatment at each temperature were ground in a wet pebble mill to 95 mm minus 325 mesh and subjected to wet magnetic separation at 2800 Gauss.

The results shown in Table II show that the nickel initially present in the pyrite and calcite becomes concentrated in the magnetic fraction to an extent dependent on the treatment temperature.

For example, at 870°C, 900°C and 925°C, approximately 87% of nickel was in the magnetic alloy concentrate, and at 814°C.

At 953°C and 1036°C, 79% of the total nickel was
0%, 75.7% and 69.3% were present in the magnetic alloy concentrate.

At 870°C, the magnetic alloy concentrate was 13% of the treated charge.
The magnetic portion contained 8.3% nickel and the non-magnetic portion contained 0.19% nickel.

At 1036°C, the magnetic alloy concentrate was 2% of the treated feed.
The magnetic portion contained 4.0% nickel and the non-magnetic portion contained 0.55% nickel.

Optimum results were obtained at 870-925°C.

Claims (1)

[Claims] 1. A method for beneficiating non-ferrous metals contained in a nickel-iron-containing iron-based sulfide ore having a stoichiometric excess of sulfur relative to iron, comprising forming an intimate mixture of a granular beneficiation sulfide concentrate of an iron-based sulfide ore containing non-ferrous metals including nickel, granular iron oxide such as pyrrhotite, and a granular reducing agent into agglomerates, and mixing the mixture in a non-oxidizing atmosphere at a ratio of 800 to 100% relative to metallic iron.
1. A method for thermally beneficiating non-ferrous metals in sulfide ore, comprising heating the mixture to 0°C for a time sufficient to reduce iron oxide to metallic iron and concentrate most of the non-ferrous metals in the iron, then cooling the mixture in a non-oxidizing atmosphere, crushing the cooled agglomerates, and separating the metallic iron from the ferrous sulfide ore to obtain a non-ferrous metal concentrate. 2. A method for beneficiating non-ferrous metals contained in a nickel-iron-containing iron-based sulfide ore having a stoichiometric excess of sulfur relative to iron, comprising forming an intimate mixture of a granular beneficiation sulfide ore concentrate of the iron-based sulfide ore containing non-ferrous metals including nickel and at least one oxide selected from the group consisting of alkali metals and alkaline earth metals into nodules, heating the nodules to 800 to 1000°C in an atmosphere non-oxidizing to metallic iron to convert the iron sulfide to metallic iron and holding the nodules for a time sufficient to concentrate most of the non-ferrous metals in the iron, then crushing the nodules, and separating the metallic iron from the iron-based sulfide ore to obtain a non-ferrous metal concentrate. 3. A method for beneficiating non-ferrous metals contained in a nickel-iron-containing iron-based sulfide ore having a stoichiometric excess of sulfur relative to iron, comprising agglomerating an intimate mixture of metallic iron and granular beneficiation sulfide ore concentrate of iron-based sulfide ore containing non-ferrous metals including nickel, heating the mixture to 800-1000°C in an atmosphere non-oxidizing to the metallic iron for a time sufficient to reduce the iron oxide to metallic iron and concentrate most of the non-ferrous metals in the iron, then cooling the mixture in a non-oxidizing atmosphere, pulverizing the cooled agglomerates, and separating the metallic iron from the iron-based sulfide ore to obtain a non-ferrous metal concentrate.