Oxygen pressure leaching method for low-grade nickel matte mixed with laterite-nickel ore

Abstract

An oxygen pressure leaching method for low-grade nickel matte mixed with laterite-nickel ore, comprising: first, carrying out beneficiation pretreatment on raw laterite-nickel ore to obtain laterite-nickel ore pulp; then mixing pretreated low-grade nickel matte and the laterite-nickel ore pulp according to a mass ratio of 2: 1-6, adding a sulfuric acid solution for an oxygen pressure leaching reaction, and controlling a reaction temperature to be 180-220℃, a pressure to be 2.5-3.5 MPa and an oxygen partial pressure to be 20-30%; and filtering a product after the oxygen pressure leaching reaction is finished, adjusting a pH value of a filtrate to 3-5, generating a precipitate, filtering out the precipitate to obtain a liquid phase, and extracting the liquid phase to obtain a nickel-cobalt-manganese sulfate solution. The present method uses a same process production line as that of high-pressure leaching of the laterite-nickel ore to simultaneously treat low-grade nickel matte and laterite-nickel ore, so as to reduce a reaction pressure and a reaction temperature of autoclaves, thus reducing energy consumption.

Description

A method for oxygen pressure leaching of low-nickel matte mixed laterite nickel ore Technical Field

[0001] The present invention belongs to the field of metallurgy, and in particular relates to an oxygen pressure leaching method for low-matte nickel mixed laterite nickel ore. Background Art

[0002] Laterite nickel ore has gradually become the main source of nickel metal. The processing technology of laterite nickel ore can be divided into pyrometallurgical processes and hydrometallurgical processes. Among them, the hydrometallurgical processes include high-pressure acid leaching and reduction roasting-ammonia leaching, as well as the more recent processes such as atmospheric pressure acid leaching and heap leaching. The high-pressure acid leaching process conditions for laterite nickel ore are 255-260°C and 5-6 MPa. Sulfuric acid is added, and the acid-ore ratio is generally around 0.3 (concentrated sulfuric acid dosage: 1 ton of dry ore). The entire leaching process is under high pressure and temperature, and has high requirements for steam energy consumption and equipment performance parameters. If the temperature and pressure during high-pressure acid leaching of laterite nickel ore can be reduced, costs can be reduced and equipment wear can be mitigated.

[0003] Low-grade nickel matte, the final product of the pyrometallurgical smelting of laterite nickel ore, is mainly composed of nickel-iron alloy. Laterite nickel ore is mixed with carbon powder and heated and roasted in a rotary kiln, converting the metal oxides in the raw ore into metal elements, forming an intermediate nickel-iron alloy (low-grade nickel matte). Generally, the production line will further heat the product in an electric furnace at around 1500°C to remove impurities, thus forming high-grade nickel matte. This process consumes a lot of energy and causes a large loss of Ni and Co. If low-grade nickel matte can be used as the raw material for processing, the loss of nickel and cobalt can be avoided and energy consumption can be reduced.

[0004] Summary of the Invention

[0005] In view of the shortcomings of the prior art, the object of the present invention is to provide an oxygen pressure leaching method for low-matte nickel mixed laterite nickel ore.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A method for oxygen pressure leaching of low-grade nickel matte mixed laterite nickel ore comprises the following steps:

[0008] (1) First, the laterite nickel ore is pretreated to obtain a laterite nickel ore pulp; then the pretreated low nickel matte and the laterite nickel ore pulp are mixed in a mass ratio of 2:1-6, and a sulfuric acid solution is added to carry out an oxygen pressure leaching reaction, and the reaction temperature is controlled to be 180-220°C, the pressure is 2.5-3.5 MPa, and the oxygen partial pressure is 20-30%;

[0009] (2) After the oxygen pressure leaching reaction is completed, the product is filtered and the pH of the filtrate is adjusted to 3-5 to generate a precipitate. The liquid phase after filtering out the precipitate is extracted to obtain a nickel-cobalt-manganese sulfate solution.

[0010] Preferably, the laterite nickel ore in step (1) is pre-treated as follows: the laterite nickel ore is washed and then screened, the -200 mesh slurry enters the finished product tank, the +200 mesh large-particle ore is processed by a spiral chute and a shaking table once to remove the chromite contained therein, and the tailings are placed in a ball mill, wet-milled for 5 minutes under the condition of a steel ball filling ratio of 50%, and then passed through a -200 mesh sieve and enter the finished product tank to form a laterite nickel ore slurry together, and after flocculant concentration and sedimentation, a laterite nickel ore slurry with a slurry concentration of 28-37% is obtained.

[0011] Preferably, the pretreatment method of the low-matte nickel in step (1) is: the low-matte nickel is ball-milled for 2 to 4 hours, wherein the water content is 50%, and the low-matte nickel is ground to 50 to 200 mesh.

[0012] Preferably, the concentration of the sulfuric acid solution in step (1) is 98 wt%.

[0013] Preferably, the ratio of the sulfuric acid solution in step (1) to the total mass of the pretreated low-matte nickel and laterite nickel ore pulp is 0.1 to 0.3:1.

[0014] Preferably, the oxygen pressure leaching reaction time in step (1) is 3 to 8 hours.

[0015] Preferably, the filtration in step (2) is pressure filtration, and the slag phase of the pressure filtration is mainly composed of Fe2O3, and also contains Al2O3, acid-insoluble silicates, and Ni < 0.05%.

[0016] Preferably, the method of adjusting the pH of the filtrate in step (2) is to add at least one of limestone and lime milk to adjust the pH.

[0017] Preferably, the extraction method in step (2) is as follows: using the extractant Versatic10 at pH = 2-3 to selectively extract Ni from the solution, and then back-extracting with a sulfuric acid solution with a concentration of 0.1-2 mol / L to obtain a high-purity nickel sulfate solution; then using a binary extraction system of Cyanex272+PC-88A to coordinately extract Co and Mn from the aqueous solution at pH = 3-5, and finally back-extracting with a sulfuric acid solution with a concentration of 0.01-0.5 mol / L to obtain a cobalt-manganese sulfate solution. These are mixed to prepare a high-purity nickel-cobalt-manganese sulfate solution.

[0018] The reaction process or mechanism involved in the present invention is:

[0019] Since the main component of nickel matte is nickel-iron alloy (Fe accounts for 45-60%, Ni accounts for 15-20%), after adding sulfuric acid, it first reacts with Fe to produce FeSO4, and then oxidizes to Fe in an oxygen atmosphere. 3+, and then hydrolyzes into Fe2O3 and enters the slag phase, while releasing sulfuric acid, which continues to dissolve the metal oxides in low-grade nickel matte and laterite nickel ore. In addition to iron and nickel, low-grade nickel matte also contains a lot of sulfur, which can also generate sulfuric acid under oxygen pressure conditions, which can effectively reduce the additional amount of sulfuric acid added. The reaction of H2 produced by the reaction of elemental iron with sulfuric acid and O2, as well as the conversion of sulfur into sulfuric acid, will release a large amount of heat, maintaining the temperature of the entire autoclave body, reducing the input of high-pressure steam, and reducing processing costs.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The present invention adopts the same process production line for high-pressure leaching of laterite nickel ore to simultaneously process low-grade nickel matte and laterite nickel ore, thereby reducing the reaction pressure and reaction temperature of the autoclave and reducing energy consumption.

[0022] (2) The amount of sulfuric acid used is reduced, the amount of steam used is reduced, and the exothermic reaction involved in the reaction in the kettle can effectively maintain the temperature of the kettle body.

[0023] (3)Fe 2+ In the leaching system, it can reduce the Cr content in the laterite nickel ore leaching solution. 6+ No need to add reducing agent treatment.

[0024] (4) The intermediate product of the laterite nickel ore pyrometallurgical process, low-matte nickel, directly enters the wet process to avoid the loss of nickel and cobalt. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG1 is a flow chart of an oxygen pressure leaching method for low-matte nickel mixed laterite nickel ore according to the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0027] The composition of the low-grade nickel matte used in the examples and comparative examples is as follows: Ni content 15-25%, Fe content 45-60%, Co content 0.1%, and S content 8-15%.

[0028] The composition of the laterite nickel ore is as follows: Ni content is 1.1-1.3%, Co content is 0.08-0.1%, Mn content is 1-3%, Fe content is 38-44%, Al content is 2-3%, and Mg content is about 2%.

[0029] The concentration of the sulfuric acid solution is 98 wt %.

[0030] The method for the mineral processing pretreatment of the laterite nickel ore is as follows:

[0031] The laterite nickel ore is washed and screened, and the -200-mesh slurry enters the finished product tank. The +200-mesh large-particle ore is processed through a spiral chute and a shaking table to remove the chromite contained therein. At the same time, the tailings are placed in a ball mill and wet-milled for 5 minutes at a steel ball filling ratio of 50%. The tailings are then screened through a -200-mesh sieve and enter the finished product tank to form a laterite nickel ore slurry. After flocculant concentration and sedimentation, a laterite nickel ore slurry with a slurry concentration of 28-37% is obtained.

[0032] The pretreatment method of the low nickel matte is: grinding the low nickel matte to 200 mesh.

[0033] Example 1

[0034] A method for oxygen pressure leaching of low-grade nickel matte mixed laterite nickel ore comprises the following steps:

[0035] (1) First, the laterite nickel ore is pretreated to obtain laterite nickel ore pulp; then 200g of the pretreated low-grade nickel matte and 400g of the laterite nickel ore pulp are mixed in a mass ratio of 1:2, and 60g of sulfuric acid solution is added to carry out oxygen pressure leaching reaction, and the ratio of the sulfuric acid solution to the total mass of the pretreated low-grade nickel matte and the laterite nickel ore pulp is 0.1:1 (i.e., the acid-ore ratio is 0.1).

[0036] The reaction temperature was controlled at 220°C, the pressure was 3.5 MPa, and the oxygen partial pressure was 30%;

[0037] (2) After 4 hours of oxygen pressure reaction, the product was filtered, and the pH of the filtrate was adjusted to 4.5 by adding limestone to generate a precipitate. The liquid phase after filtering out the precipitate was extracted to obtain a nickel-cobalt-manganese sulfate solution.

[0038] After oxygen pressure leaching, the pH of the leachate is between 0.1 and 0.9, with Ni concentrations >20g / L, Co >0.5g / L, Fe <2g / L, and Al <1.5g / L. The Ni content in the slag phase is <0.08%. The acid-ore ratio is reduced to 0.1 throughout the process, significantly reducing sulfuric acid usage.

[0039] Example 2

[0040] A method for oxygen pressure leaching of low-grade nickel matte mixed laterite nickel ore comprises the following steps:

[0041] The only difference between this embodiment and embodiment 1 is that:

[0042] The ratio of low-grade nickel matte to laterite nickel ore pulp in step 1 is 1:3, that is, 200g of pretreated low-grade nickel matte and 600g of laterite nickel ore pulp, and other conditions are the same as in Example 1.

[0043] After changing the ratio of nickel matte to laterite nickel ore, the pH of the leachate rose to 1.1, with Ni contents exceeding 17 g / L, Co exceeding 0.4 g / L, Fe below 2 g / L, and Al below 1.5 g / L. The Ni content in the slag phase was less than 1.2%. The reduced nickel matte content resulted in an insufficient acid-ore ratio of 0.1 to fully dissolve the nickel. Therefore, increasing the acid-ore ratio was necessary to increase the leaching rates of Ni and Co.

[0044] Example 3

[0045] A method for oxygen pressure leaching of low-grade nickel matte mixed laterite nickel ore comprises the following steps:

[0046] The only difference between this embodiment and embodiment 1 is that:

[0047] The oxygen partial pressure was reduced to 20%, while other conditions remained unchanged.

[0048] The role of oxygen in the autoclave is to oxidize ferrous iron and combine with H2 produced by the reaction of sulfur in the low-grade nickel matte, releasing heat. When the oxygen partial pressure drops to 20%, the Fe content in the leachate increases to <4.2g / L, while the Ni and Co contents decrease to <15g / L and <0.35g / L, respectively. The residual Ni and Co in the slag phase also increases. This is mainly due to the decrease in O2 content, which leads to the decrease of Fe 2+ It cannot be completely oxidized, the acid content is reduced, and Ni and Co cannot be completely dissolved.

[0049] Example 4

[0050] A method for oxygen pressure leaching of low-grade nickel matte mixed laterite nickel ore comprises the following steps:

[0051] The only difference between this embodiment and embodiment 1 is that:

[0052] The reaction time of the oxygen pressure reaction was 2 h, and other conditions remained unchanged.

[0053] Shorten the oxygen pressure reaction time. The Fe content in the leaching solution is >15g / L, Ni <10g / L, Co <0.2g / L, Al <4g / L. Insufficient reaction time will lead to Fe 3+ The conversion has not been completed and the leaching rate has decreased.

[0054] Comparative Example 1

[0055] A method for oxygen pressure leaching of laterite nickel ore, comprising the following steps:

[0056] The only difference between this comparative example and Example 1 is that in step (1), no low-matte nickel is added, and the leaching effect of laterite nickel ore under the same conditions is compared.

[0057] Without the addition of matte nickel, high-pressure leaching under these conditions yielded leaching rates of less than 10% for both Ni and Co in laterite nickel ore. The low temperature and pressure prevented the reaction from proceeding, and the low acid content prevented dissolution of Ni and Co. The final leachate pH was 3, with Ni <1g / L, Co <0.02g / L, Fe <7g / L, and Al <5g / L.

[0058] Comparative Example 2

[0059] A method for preparing a nickel-cobalt-manganese sulfate solution comprises the following steps:

[0060] The only difference between this comparative example and Example 1 is that in step (2), no limestone is added to the leachate to adjust the pH and remove iron and aluminum impurities, and extraction is carried out directly, while other conditions remain unchanged.

[0061] The high Fe and Al contents in the leachate significantly affected the selectivity of Ni extraction using the extractant Versatic 10, reducing the Ni extraction rate from 98% to 64%. The Fe and Al that enter the loaded organic phase affect the reusability of the extractant.

[0062] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. An oxygen pressure leaching method for low nickel matte mixed laterite nickel ore, characterized in that: The steps include: (1) First, the raw laterite nickel ore is pretreated to obtain laterite nickel ore pulp; then the pretreated low nickel matte and laterite nickel ore pulp are mixed in a mass ratio of 2:1-6, and sulfuric acid solution is added to carry out oxygen pressure leaching reaction, and the reaction temperature is controlled to be 180-220°C, the pressure is 2.5-3.5Mpa, and the oxygen partial pressure is 20-30%; (2) After the oxygen pressure leaching reaction is completed, the product is filtered, and the pH of the filtrate is adjusted to 3-5 to generate a precipitate. The liquid phase after filtering out the precipitate is extracted to obtain a nickel-cobalt-manganese sulfate solution.

2. The oxygen pressure leaching method of low-matte nickel mixed laterite nickel ore according to claim 1, characterized in that: The ratio of the sulfuric acid solution in step (1) to the total mass of the pretreated low-grade nickel matte and laterite nickel ore slurry is 0.1 to 0.3:

1.

3. The oxygen pressure leaching method of low nickel matte mixed laterite nickel ore according to claim 1, characterized in that: The method for the beneficiation pretreatment of the laterite nickel ore in step (1) is as follows: the laterite nickel ore is screened after washing, the -200 mesh slurry enters the finished product tank, the +200 mesh large particle ore is processed by a spiral chute and a shaking table once to remove the chromite contained therein, and the tailings are placed in a ball mill, wet-milled for 5 minutes under the condition of a steel ball filling ratio of 50%, and then passed through a -200 mesh sieve and enter the finished product tank to form a laterite nickel ore slurry together, and after flocculant concentration and sedimentation, a laterite nickel ore slurry with a slurry concentration of 28-37% is obtained.

4. The oxygen pressure leaching method of low-matte nickel mixed laterite nickel ore according to any one of claims 1 to 3, characterized in that: The pretreatment method of the nickel matte in step (1) is: the nickel matte is ball milled in a ball mill for 2 to 4 hours, wherein the water content is 50%, and the nickel matte is ground to 50 to 200 meshes.

5. The oxygen pressure leaching method of low-matte nickel mixed laterite nickel ore according to claim 4, characterized in that: The concentration of the sulfuric acid solution in step (1) is 98wt%.

6. The oxygen pressure leaching method of low-matte nickel mixed laterite nickel ore according to claim 5, characterized in that: The oxygen pressure leaching reaction time in step (1) is 3 to 8 hours.

7. The oxygen pressure leaching method of low-matte nickel mixed laterite nickel ore according to any one of claims 1 to 3, characterized in that: The filtration in step (2) is filter pressing.

8. The oxygen pressure leaching method of low-matte nickel mixed laterite nickel ore according to claim 7, characterized in that: The method of adjusting the pH of the filtrate in step (2) is: adding at least one of limestone and lime milk to adjust the pH.

9. The oxygen pressure leaching method of low-matte nickel mixed laterite nickel ore according to claim 1, characterized in that: In step (2), the pH of the filtrate is adjusted to 4.

5.

10. The oxygen pressure leaching method of low-matte nickel mixed laterite nickel ore according to claim 1, characterized in that: The extraction method of step (2) is as follows: using the extractant Versatic10 to selectively extract Ni in the solution under the condition of pH=2-3, and performing back extraction with a sulfuric acid solution with a concentration of 0.1-2 mol / L to obtain a nickel sulfate solution; then using a binary extraction system of Cyanex272+PC-88A to coordinately extract Co and Mn from the aqueous phase solution under the condition of pH=3-5, and finally performing back extraction with a sulfuric acid solution with a concentration of 0.01-0.5 mol / L to obtain a cobalt manganese sulfate solution; and mixing the nickel sulfate solution with the cobalt manganese sulfate solution to prepare a nickel cobalt manganese sulfate solution.

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