Method for preparing iron phosphate and MHP through collaborative smelting of ferronickel and laterite-nickel ore

Abstract

The invention discloses a method for preparing iron phosphate and MHP through collaborative smelting of ferronickel and laterite-nickel ore, and relates to the technical field of wet smelting. The method comprises the following steps: leaching ferronickel by using a mixed acid solution containing sulfuric acid and phosphoric acid, oxidizing ferronickel pickle liquor to precipitate iron phosphate so as to obtain an iron phosphate and nickel sulfate solution, mixing ferronickel acid leaching residues with laterite-nickel ore for high-pressure acid leaching, or mixing with laterite-nickel ore leaching liquor, or returning a liquid phase to the ferronickel-sulfur-phosphorus mixed acid for leaching after high-acid leaching, the nickel element in the slag is further recovered; the method comprises the following steps: mixing a nickel sulfate solution with a high-pressure acid leaching solution in a laterite-nickel ore wet smelting process, and carrying out an impurity removal process to prepare crude nickel cobalt hydroxide (MHP); and the high-pressure wet process system of the laterite-nickel ore is cooperatively operated to form a material exchange mechanism, so that slag and liquid which are produced by a ferronickel system and are difficult to treat independently or have higher treatment cost are treated at low cost, and an iron phosphate product is produced while valuable metal elements are efficiently recycled.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, and in particular to a method for preparing ferric phosphate and MHP by coordinated smelting of ferronickel and laterite nickel ore. Background Art

[0002] Nickel iron contains rich nickel and iron resources and is mainly used as an alloy additive in the production process of stainless steel. However, in many areas, nickel iron is in oversupply in the stainless steel field. With the rapid development of new energy, ternary batteries have been widely used, and the demand for nickel (mainly nickel sulfate) has increased significantly, and it is currently in short supply. In addition, lithium iron phosphate has a large market share in the field of new energy vehicles due to its advantages of good safety and low cost. As a precursor for the preparation of lithium iron phosphate, the market demand for iron phosphate is also very large.

[0003] Since nickel resources in nickel iron are more precious, in order to convert it into ternary materials, generally only the nickel metal is refined, while the iron is ignored, which easily leads to waste of iron resources. In addition, the existing nickel iron leaching process has the following problems: large nickel and cobalt loss, high cost, and high impurity content of the product.

[0004] Therefore, there is an urgent need to develop a new method for recovering nickel iron that can reduce process costs while increasing the recovery rate of valuable metals.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The object of the present invention is to provide a method for preparing ferric phosphate and MHP by co-smelting ferronickel and laterite nickel ore, aiming to reduce process costs while improving the recovery rate of valuable metals.

[0007] The present invention is achieved in that:

[0008] In a first aspect, the present invention provides a method for preparing ferrophosphate and MHP by co-smelting ferronickel and laterite nickel ore, comprising: acid leaching ferronickel with a mixed acid solution containing sulfuric acid and phosphoric acid, and obtaining ferronickel acid leaching solution and ferronickel acid leaching residue after solid-liquid separation;

[0009] The nickel-iron acid leaching solution is reacted in the presence of an oxidant and a neutralizer, and iron phosphate and nickel sulfate solutions are obtained through solid-liquid separation;

[0010] The nickel-iron acid leaching residue is mixed with laterite nickel ore, and high-pressure acid leaching is performed to obtain a high-pressure acid leaching solution;

[0011] and / or, mixing the nickel-iron acid leaching residue with a laterite nickel ore high-pressure acid leaching solution;

[0012] and / or, adding acid to the nickel-iron acid leaching residue and then leaching it again, and returning the leaching solution to the nickel-iron-sulfur-phosphorus mixed acid leaching process;

[0013] The nickel sulfate solution and the high-pressure acid leaching solution are mixed, and crude nickel cobalt hydroxide is prepared after the impurity removal process in the laterite nickel ore hydrometallurgy.

[0014] In an optional embodiment, the process of high-pressure acid leaching includes: mixing nickel-iron acid leaching residue with laterite nickel ore, the dry basis mass ratio of nickel-iron acid leaching residue to laterite nickel ore is not higher than 1:100, the acid-ore ratio is controlled to be 200Kg / t ore-500Kg / t ore, the acid-ore ratio is the ratio of sulfuric acid and nickel-iron acid leaching residue to the total dry weight of laterite nickel ore, and the leaching pressure of high-pressure leaching is controlled to be 4MPa-6MPa.

[0015] In an optional embodiment, the steps of wet smelting of laterite nickel ore include high-pressure acid leaching, pre-neutralization, one-stage iron and aluminum removal, two-stage iron and aluminum removal, one-stage nickel and cobalt precipitation, product filtration and two-stage nickel and cobalt precipitation, etc., and the nickel sulfate solution and the high-pressure acid leaching solution are mixed in the pre-neutralization or one-stage iron and aluminum removal stage; and / or, the nickel-iron acid leaching residue and the high-pressure acid leaching solution are mixed in the pre-neutralization stage.

[0016] In an optional embodiment, the acid leaching temperature of nickel iron is controlled to be 20° C.-90° C., the reaction pH value is 1.0-2.0, and the reaction time is 1 h-10 h.

[0017] In an optional embodiment, the process of preparing nickel-iron acid leaching solution and nickel-iron acid leaching residue includes: mixing nickel-iron powder and water to obtain nickel-iron slurry, mixing the nickel-iron slurry with phosphoric acid and sulfuric acid for acid leaching, and then separating the solid and liquid and washing the obtained solid material.

[0018] In an optional embodiment, when preparing nickel-iron slurry, the liquid-to-solid mass ratio is controlled to be (3-15):1;

[0019] Optionally, the molar ratio of the P content added to the phosphoric acid to the Fe content in the nickel-iron powder is (0.8-1.2):1.

[0020] In an optional embodiment, the nickel-iron powder is obtained by crushing the nickel-iron alloy, and the composition of the nickel-iron alloy is as follows, by mass percentage: Ni 5%-25%, Fe 60%-90%; the particle size of the nickel-iron powder is not more than 75 μm.

[0021] In an optional embodiment, during the reaction of the nickel-iron acid leaching solution in the presence of an oxidant and a neutralizer, the reaction temperature is controlled to be 20° C.-90° C., the reaction pH value is 0.5-2.5, the reaction time is 1 h-10 h, and the nickel sulfate solution obtained after the reaction contains Fe 2+ The concentration is not less than 0.01g / L.

[0022] In an optional embodiment, the oxidant is selected from at least one of hydrogen peroxide, oxygen, enriched oxygen and air.

[0023] In an optional embodiment, the neutralizing agent is selected from at least one of aqueous ammonia, sodium hydroxide, potassium hydroxide, calcium hydroxide, calcium oxide, nickel oxide, nickel carbonate and nickel hydroxide.

[0024] The invention has the following beneficial effects: the invention utilizes a mixed acid solution containing sulfuric acid and phosphoric acid to leach nickel iron, and the nickel iron acid leaching solution is oxidized to precipitate iron phosphate to obtain an iron phosphate and nickel sulfate solution, and the nickel iron acid leaching residue is mixed with laterite nickel ore for high-pressure acid leaching, or mixed with laterite nickel ore leaching solution, or after high-acid leaching, the liquid phase is returned to nickel iron sulfur phosphorus mixed acid leaching to further recover the nickel element in the residue, and at the same time, the nickel iron acid leaching residue enters the high-pressure acid leaching process and can be used as a reducing agent (the reducing agent is the leached residual nickel, iron and carbon) to reduce the Cr in the leaching solution. 6+ The nickel sulfate solution is mixed with the high-pressure acid leaching solution in the laterite nickel ore hydrometallurgy process, and the crude nickel cobalt hydroxide (MHP) is prepared through impurity removal and other processes. The Fe in the nickel sulfate solution 2+ It can be used as a reducing agent to reduce Cr in high pressure acid leaching solution. 6+ Reduction, part of Fe 2+ It can be used as a reducing agent in the laterite nickel ore hydrometallurgy system to reduce the consumption of phosphoric acid and oxidant in the nickel-iron leaching process. 6+ Dynamically adjust the amount of phosphoric acid and oxidant added in the nickel-iron leaching process to make the Fe content in the nickel-iron acid leaching solution 2+ The advanced technology can meet the requirements of Cr removal in laterite nickel ore hydrometallurgy system. 6+ The nickel-iron leaching system operates in coordination with the laterite nickel ore high-pressure wet process system to form a material exchange mechanism, which enables the slag and liquid produced by the nickel-iron system, which are difficult to process separately or have high processing costs, to be processed at low cost, and the valuable metal elements therein are efficiently recovered while producing iron phosphate products. In addition, the parallel setting and operation with the laterite nickel ore high-pressure leaching system can reduce the cost of equipment construction, labor and auxiliary materials, has great economic benefits, and is suitable for industrial production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 A process flow chart provided for an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0028] The existing nickel-iron leaching process focuses on nickel metal refining and ignores the recovery of iron, which easily leads to waste of iron resources. In view of this, the inventors have coordinated the operation of the nickel-iron leaching process and the laterite nickel ore high-pressure wet process system to form a material exchange mechanism, which can rationally utilize the nickel and iron in the nickel-iron. While extracting nickel, iron can also be prepared into iron phosphate with higher economic value, which can not only optimize the balance of nickel resource supply and demand, but also meet the market demand for ternary materials and iron phosphate materials.

[0029] Please refer to Figure 1 The present invention provides a method for preparing ferric phosphate and MHP by co-smelting ferronickel and laterite nickel ore, comprising the following steps:

[0030] S1, Nickel-iron acid leaching

[0031] The nickel-iron is acid-leached with a mixed acid solution containing sulfuric acid and phosphoric acid to more fully leach nickel and iron, and nickel-iron acid leaching solution and nickel-iron acid leaching residue are obtained after solid-liquid separation.

[0032] In some embodiments, nickel iron powder and water are mixed to obtain nickel iron slurry, the nickel iron slurry is mixed with phosphoric acid, and then mixed with sulfuric acid to adjust the pH value to meet the leaching conditions, the acid leaching temperature is controlled to be 20°C-90°C, the reaction pH value is 1.0-2.0, the reaction time is 1h-10h, and after the reaction is completed, the solid-liquid is separated and the obtained solid material is washed to obtain nickel iron acid leaching solution and nickel iron acid leaching residue.

[0033] Specifically, the acid leaching temperature can be 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, etc., the reaction pH value can be 1.0, 1.3, 1.5, 1.8, 2.0, etc., and the reaction time can be 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, etc.

[0034] Furthermore, when mixed with water to make pulp, the liquid-to-solid mass ratio is controlled to be (3-15):1, such as 3:1, 5:1, 8:1, 10:1, 12:1, 15:1, etc. The liquid-to-solid mass ratio within the above range is conducive to the sufficient leaching of nickel iron.

[0035] Further, the nickel-iron powder is obtained by crushing the nickel-iron alloy, and the composition of the nickel-iron alloy is as follows by mass percentage: Ni 5%-25%, Fe 60%-90%. The nickel-iron content within the above range is suitable for treatment by the process provided by the embodiment of the present invention, and the nickel-iron can be fully recovered. The particle size of the nickel-iron powder is not more than 75μm, that is, the particle size is less than or equal to 75μm, so as to fully contact with the mixed acid solution during acid leaching and improve the effect of acid leaching.

[0036] Specifically, in the nickel-iron alloy, the mass fraction of Ni can be 5%, 10%, 13%, 15%, 18%, 20%, 25%, etc.; the mass fraction of Fe can be 60%, 70%, 80%, 90%, etc.

[0037] Further, the amount of phosphoric acid added is calculated according to the Fe content in the ferronickel powder, and the molar ratio of the P content in the phosphoric acid to the Fe content in the ferronickel powder is (0.8-1.2):1, such as 0.8:1, 0.9:1, 1.0:1, 1.1:1, 1.2:1, etc. The amount of phosphoric acid added is regulated so that most of the iron is subsequently precipitated to obtain iron phosphate.

[0038] S2. Oxidation precipitation

[0039] The nickel-iron acid leaching solution is mixed with an oxidant and a neutralizer for reaction. After the reaction is completed, solid-liquid separation is performed, and the obtained solid material is washed and dried to obtain iron phosphate and nickel sulfate solutions. The pH value of the reaction is regulated by a neutralizer to oxidize the divalent iron in the acid leaching solution and generate iron phosphate precipitation.

[0040] In some embodiments, during the reaction of the nickel-iron acid leaching solution in the presence of an oxidant and a neutralizer, the reaction temperature is controlled to be 20°C-90°C, the reaction pH value is 0.5-2.5, and the reaction time is 1h-10h. The reaction conditions are preferably within the above ranges to allow iron to be fully deposited and improve the recovery rate of the raw materials. The nickel sulfate solution obtained after the reaction contains Fe 2+ The concentration should not be less than 0.01g / L.

[0041] Specifically, the reaction temperature can be 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, etc., the reaction pH can be 0.5, 1.0, 1.3, 1.5, 1.8, 2.0, 2.5, etc., and the reaction time can be 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, etc.

[0042] In some embodiments, the oxidant is selected from at least one of hydrogen peroxide, oxygen, oxygen-enriched air, and air, and the oxidant may be any one or more of the above; the neutralizer is selected from at least one of ammonia water, sodium hydroxide, potassium hydroxide, calcium hydroxide, calcium oxide, nickel oxide, nickel carbonate, and nickel hydroxide, and the neutralizer may be any one or more of the above. The amount of the oxidant is sufficient to reduce Cr in the high-pressure acid leaching solution of laterite nickel ore while oxidizing and precipitating most of the Fe. 6+ According to the needs, the pH value of the reaction can be adjusted to meet the process requirements by adjusting the dosage of the neutralizer.

[0043] S3, nickel-iron acid leaching residue re-leaching

[0044] The nickel-iron acid leaching residue obtained in step S1 is mixed with laterite nickel ore and subjected to high-pressure acid leaching to obtain a high-pressure acid leaching solution, or mixed with laterite nickel ore leaching solution, or the liquid phase is returned to nickel-iron-sulfur-phosphorus mixed acid leaching after high-acid leaching to further recover the nickel element in the residue. At the same time, the nickel-iron acid leaching residue enters the high-pressure acid leaching process and can be used as a reducing agent to reduce the Cr in the leaching solution. 6+ The laterite nickel ore may be a common limonite-type laterite nickel ore, and the high-pressure acid leaching may be a high-pressure acid leaching process in the hydrometallurgy of laterite nickel ore, which may be carried out in an autoclave.

[0045] It should be noted that the embodiment of the present invention operates the nickel-iron leaching process in coordination with the laterite nickel ore high-pressure wet process system to form a material exchange mechanism, so that the slag produced by the nickel-iron system that is difficult to process alone or has a high processing cost can be processed at a low cost.

[0046] In some embodiments, the process of high-pressure acid leaching includes: mixing nickel-iron acid leaching residue with laterite nickel ore, the dry basis mass ratio of nickel-iron acid leaching residue to laterite nickel ore is not higher than 1:100, the acid-ore ratio is controlled to be 200Kg / t ore-500Kg / t ore, and the acid-ore ratio is the ratio of sulfuric acid and nickel-iron acid leaching residue to the total dry weight of laterite nickel ore, and the leaching pressure of high-pressure leaching is controlled to be 4MPa-6MPa.

[0047] The dry basis mass ratio of nickel-iron acid leaching residue to laterite nickel ore is not higher than 1:100, and specifically the dry basis mass ratio is 1:100, 1:500, 1:1000, 1:5000, 1:10000, etc. The acid-ore ratio is controlled to be 200Kg / t ore-500Kg / t ore, and the leaching pressure is controlled to be 4MPa-6MPa to fully leach valuable metals. Specifically, the leaching pressure can be 4.0MPa, 4.5MPa, 5.0MPa, 5.5MPa, 6.0MPa, etc.

[0048] S4. Use the hydrometallurgical process of laterite nickel ore to remove impurities

[0049] The nickel sulfate solution and the high-pressure acid leaching solution are mixed and subjected to impurity removal and other processes in the laterite nickel ore hydrometallurgy to prepare crude nickel cobalt hydroxide. The impurity removal process in the laterite nickel ore hydrometallurgy is used to treat the nickel sulfate solution which is difficult to treat and has a high treatment cost, which can further reduce the process cost.

[0050] In some embodiments, the steps of hydrometallurgy of laterite nickel ore include high-pressure acid leaching, pre-neutralization, one-stage iron and aluminum removal, two-stage iron and aluminum removal, one-stage nickel and cobalt precipitation, product filtration and two-stage nickel and cobalt precipitation, etc., which are performed in sequence. In the pre-neutralization or one-stage iron and aluminum removal stage, the nickel sulfate solution and the high-pressure acid leaching solution are mixed to purify and remove impurities, and nickel and cobalt are precipitated to finally obtain crude nickel cobalt hydroxide (MHP).

[0051] In some embodiments, the nickel-iron acid leaching residue is mixed with laterite nickel ore high pressure acid leaching solution in the pre-neutralization stage, and the valuable metals in the nickel-iron acid leaching residue are re-leached using the residual acid in the laterite nickel ore high pressure acid leaching solution.

[0052] Specifically, the specific steps of laterite nickel ore hydrometallurgy include: high-pressure acid leaching, pre-neutralization, first-stage iron and aluminum removal, second-stage iron and aluminum removal, first-stage nickel and cobalt precipitation, product filtration, second-stage nickel and cobalt precipitation, etc. Each step is described in detail:

[0053] Pre-neutralization can use limestone and other raw materials to neutralize the leachate, so that the pH value of the acid leachate is 1.5-2.0, and the residual acid in the leachate is neutralized by a neutralizer to obtain a neutralized leachate;

[0054] One-stage iron and aluminum removal refers to adjusting the pH value of the neutralized leaching solution to 3.5-4.0 (may be adjusted by limestone, but not limited thereto), performing a stage of purification, and obtaining a stage of purified liquid and a stage of purified slag;

[0055] The second stage of iron and aluminum removal refers to continuing to adjust the pH value of the first stage purification liquid to 4.5-5.0 (may be adjusted by limestone, but not limited to this), and performing a second stage of purification to remove the remaining iron and aluminum again to obtain a second stage of purification liquid and a second stage of purification slag;

[0056] One-stage nickel-cobalt precipitation refers to mixing the second-stage purified liquid with sodium hydroxide, adjusting the pH value to 7.0-7.6 for one-stage nickel-cobalt precipitation. The obtained one-stage nickel-cobalt precipitate can be directly processed into products, and the obtained one-stage nickel-cobalt precipitation liquid enters the next process;

[0057] Product filtration refers to the filtration through a filter press after the first stage of nickel and cobalt precipitation is completed to obtain the nickel and cobalt hydroxide product and the filtrate washing liquid after the first stage of nickel and cobalt precipitation;

[0058] The second stage nickel-cobalt precipitation is to mix the first stage nickel-cobalt precipitation liquid and the filtrate and washing liquid with lime milk, adjust the pH value to 7.6-8.5, carry out the second stage nickel-cobalt precipitation, and obtain the second stage nickel-cobalt precipitate and the second stage nickel-cobalt precipitation liquid after solid-liquid separation.

[0059] It should be added that the residual laterite nickel ore, which is difficult to handle by the high-pressure acid leaching system, is produced through the pyrometallurgical route to produce nickel iron, and finally returns to the hydrometallurgical system to produce nickel sulfate, realizing the technical path of using all resources of laterite nickel ore as raw materials for ternary batteries.

[0060] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0061] It should be noted that the nickel-iron alloy used in the following embodiments and comparative examples is a commercially available material, and its composition, by mass percentage, is as follows: Ni content is 14.45%, Fe content is 80.43%, and impurities are mainly Al, Mn, Si, C, and S, wherein the contents of Al and Mn are less than 0.1%, and the contents of Si, C, and S are less than 0.5%.

[0062] It should be noted that the hydrometallurgy of laterite nickel ore includes high-pressure acid leaching, pre-neutralization, first-stage iron and aluminum removal, second-stage iron and aluminum removal, first-stage nickel and cobalt precipitation, product filtration, and second-stage nickel and cobalt precipitation. Each step is described in detail:

[0063] Pre-neutralization: using limestone slurry to neutralize the leachate, making the pH value at the reaction end point 2.0, and using limestone to neutralize the residual acid in the leachate to obtain a neutralized leachate;

[0064] The pH value of the neutralized leaching solution is adjusted to 3.6 by using limestone slurry, and a first-stage purification is performed to obtain a first-stage purified liquid and a first-stage purified slag;

[0065] Continue to add limestone to adjust the pH value of the first stage purified liquid to 4.8, and perform second stage purification to remove the remaining iron and aluminum again to obtain second stage purified liquid and second stage purified slag;

[0066] The second stage purified liquid is mixed with sodium hydroxide, and the pH value is adjusted to 7.6 to perform a first stage nickel-cobalt precipitation. The first stage nickel-cobalt precipitate is filtered through a product filter to obtain a nickel-cobalt hydroxide product and a filtrate. The first stage nickel-cobalt precipitation liquid and the filtrate are fed to the next process.

[0067] The first stage nickel-cobalt precipitation liquid, the filtrate and the lime milk are mixed, the pH value is adjusted to 8.2, and the second stage nickel-cobalt precipitation is carried out. After solid-liquid separation, the second stage nickel-cobalt precipitate and the second stage nickel-cobalt precipitation liquid are obtained.

[0068] Example 1

[0069] This embodiment provides a method for preparing iron phosphate and MHP by co-smelting ferronickel and laterite nickel ore, the steps are as follows:

[0070] (1) The nickel-iron alloy is crushed into nickel-iron powder with a particle size of less than 75 μm, and water is added to the slurry at a liquid-solid ratio of 10:1 (mass ratio, the same below), and 85% by mass phosphoric acid is added at a P / Fe molar ratio of 1.0, and 98% by mass sulfuric acid is added to adjust the pH value to 1.5 for acid leaching. The acid leaching temperature is 90° C., the pH value is 1.0, and the reaction time is 2 h. After solid-liquid separation and washing of the leached slurry, nickel-iron acid leaching solution and nickel-iron acid leaching residue are obtained.

[0071] (2) Add an oxidant (hydrogen peroxide) and a neutralizer (ammonia water) to the nickel-iron acid leaching solution to react, and add ammonia water to control the pH value to 2.0, so that Fe in the acid leaching solution after the reaction 2+ The concentration dropped to 3g / L, the reaction temperature was 70°C, and the reaction time was 4h. After the reaction, the slurry was subjected to solid-liquid separation, washing, and drying to obtain iron phosphate and nickel sulfate solutions.

[0072] (3) The nickel-iron acid leaching residue obtained in step (1) is put into an autoclave together with a certain oxidized limonite-type laterite nickel ore for high-pressure acid leaching. The specific operation is as follows: the dry basis mass ratio of the nickel-iron acid leaching residue to the laterite nickel ore is 0.2:100, the acid-ore ratio is controlled to be 360Kg / t ore, and the leaching pressure is controlled to be 4.6MPa.

[0073] (4) The nickel sulfate solution obtained in step (2) is sent to the main system for hydrometallurgical refining of laterite nickel ore and mixed with the high-pressure acid leaching solution of laterite nickel ore without adding any additional reducing agent. After purification and impurity removal, nickel and cobalt precipitation, crude nickel cobalt hydroxide (MHP) is finally obtained.

[0074] Product testing:

[0075] The obtained ferric phosphate product was analyzed for composition, and the Fe content in the ferric phosphate was 29.85%, the phosphorus content was 16.85%, the Fe / P ratio was 0.98, the Ni content in the product was 0.004%, the Co content was 0.003%, the Al content was 0.01%, and the Mn content was 0.013%;

[0076] The crude nickel cobalt hydroxide (MHP) obtained was subjected to component analysis, and the results were as follows: the Ni content in MHP was 40.56%, the Co content was 4.02%, the Fe content was 0.05%, the Al content was 0.12%, the Cr content was 0.005%, the Mn content was 5.86%, and the Mg content was 1.35%.

[0077] Example 2

[0078] This embodiment provides a method for preparing iron phosphate and MHP by co-smelting ferronickel and laterite nickel ore, the steps are as follows:

[0079] (1) The nickel-iron alloy is crushed into nickel-iron powder with a particle size of less than 75 μm, water is added to the powder at a liquid-solid ratio of 10:1, 85% by mass phosphoric acid is added at a P / Fe molar ratio of 1.0, and 98% by mass sulfuric acid is added to adjust the pH value to 2.0 for acid leaching. The acid leaching temperature is 90° C., the pH value is 1.0, and the reaction time is 3 h. After solid-liquid separation and washing of the leached slurry, nickel-iron acid leaching solution and nickel-iron acid leaching residue are obtained.

[0080] (2) Add an oxidant (hydrogen peroxide) and a neutralizer (ammonia water) to the nickel-iron acid leaching solution to react, and add ammonia water to control the pH value to 1.5, so that Fe 2+ The concentration dropped to 3g / L, the reaction temperature was 70°C, and the reaction time was 4h. After the reaction, the slurry was subjected to solid-liquid separation, washing, and drying to obtain iron phosphate and nickel sulfate solutions.

[0081] (3) The nickel-iron acid leaching residue obtained in step (1) is put into an autoclave together with a certain oxidized limonite-type laterite nickel ore for high-pressure acid leaching. The specific operation is as follows: the dry basis mass ratio of the nickel-iron acid leaching residue to the laterite nickel ore is 0.2:100, the acid-ore ratio is controlled to be 360Kg / t ore, and the leaching pressure is controlled to be 4.6MPa.

[0082] (4) The nickel sulfate solution obtained in step (2) is sent to the main system for hydrometallurgical refining of laterite nickel ore and mixed with the high-pressure acid leaching solution of laterite nickel ore without adding any additional reducing agent. After purification and impurity removal, nickel and cobalt precipitation, crude nickel cobalt hydroxide (MHP) is finally obtained.

[0083] Product testing:

[0084] The obtained ferric phosphate product was analyzed for composition, and the Fe content in the ferric phosphate was 29.70%, the phosphorus content was 16.70%, the Fe / P ratio was 0.99, the Ni content in the product was 0.004%, the Co content was 0.004%, the Al content was 0.01%, and the Mn content was 0.009%;

[0085] The crude nickel cobalt hydroxide (MHP) obtained was subjected to component analysis, and the results were as follows: the Ni content in MHP was 40.79%, the Co content was 4.06%, the Fe content was 0.06%, the Al content was 0.13%, the Cr content was 0.004%, the Mn content was 5.76%, and the Mg content was 1.37%.

[0086] Example 3

[0087] The only difference from Example 1 is that the Fe in the nickel-iron leaching solution after oxidation reaction is 2+ The concentration is 2g / L.

[0088] The impurity Cr content in crude nickel cobalt hydroxide (MHP) increased from 0.005% to 0.014%.

[0089] Example 4

[0090] The only difference from Example 1 is that the Fe in the nickel-iron leaching solution after oxidation reaction is 2+ The concentration is 1g / L.

[0091] The impurity Cr content in crude nickel cobalt hydroxide (MHP) increased from 0.005% to 0.025%.

[0092] The results show that the process provided by the present invention can not only improve the recovery rate of Ni and Co metals in nickel iron, but also recycle the iron element in nickel iron to prepare the raw material of the precursor material required for power batteries, while also reducing waste residue emissions and lowering processing costs. 2+ The unleached nickel and iron in the nickel-iron leaching slag enter the laterite nickel ore hydrometallurgy system and play the role of reducing agent, which can effectively reduce the impurity Cr content in the MHP product of laterite nickel ore hydrometallurgy.

[0093] In summary, the present invention provides a method for preparing ferrophosphate and MHP by synergistic smelting of ferronickel and laterite nickel ore, wherein the ferronickel powder is first subjected to mixed acid leaching of phosphoric acid and sulfuric acid, and then the ferronickel acid leaching residue is further mixed with laterite nickel ore for high-pressure acid leaching, or mixed with laterite nickel ore leaching solution, or the liquid phase after high-acid leaching is returned to the nickel-iron-sulfur-phosphorus mixed acid leaching, thereby maximizing the leaching rate of valuable metals in the ferronickel powder and improving the metal recovery rate. The ferronickel acid leaching solution is oxidized to remove Fe in the solution. 2+ Oxidation and reaction with phosphate in the solution to form iron phosphate precipitation, the operation is simple, and the Fe / P ratio of the prepared iron phosphate product is between 0.96 and 1. The nickel sulfate solution is mixed with the high-pressure acid leaching solution of laterite nickel ore, and the MHP product can be obtained after further impurity removal and nickel-cobalt precipitation process, which can replace the reducing agent in the laterite nickel ore hydrometallurgy system and reduce the cost of auxiliary materials.

[0094] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing iron phosphate and MHP by smelting ferronickel and laterite nickel ore, characterized in that: include: A mixed acid solution containing sulfuric acid and phosphoric acid is used to acid-leach ferronickel, and ferronickel acid-leach solution and ferronickel acid-leach residue are obtained after solid-liquid separation; The nickel-iron acid leaching solution is reacted in the presence of an oxidant and a neutralizer to obtain iron phosphate and nickel sulfate solutions through solid-liquid separation; The nickel-iron acid leaching residue is mixed with laterite nickel ore, and high-pressure acid leaching is performed to obtain a high-pressure acid leaching solution; and / or, the nickel-iron acid leaching residue is mixed with the laterite nickel ore high-pressure acid leaching solution; and / or, adding acid to the nickel-iron acid leaching residue and then leaching it again, and returning the leaching solution to the nickel-iron-sulfur-phosphorus mixed acid leaching process; The nickel sulfate solution and the high-pressure acid leaching solution are mixed, and crude nickel cobalt hydroxide is prepared after the impurity removal process in the laterite nickel ore wet smelting.

2. The method according to claim 1, characterized in that The high-pressure acid leaching process includes: mixing nickel-iron acid leaching residue with laterite nickel ore, the dry basis mass ratio of nickel-iron acid leaching residue to laterite nickel ore is not higher than 1:100, the acid-ore ratio is controlled to be 200Kg / t ore-500Kg / t ore, the acid-ore ratio is the ratio of sulfuric acid and nickel-iron acid leaching residue to the total dry weight of laterite nickel ore, and the leaching pressure of high-pressure leaching is controlled to be 4MPa-6MPa.

3. The method according to claim 1, characterized in that The steps of the laterite nickel ore wet smelting include high-pressure acid leaching, pre-neutralization, one-stage iron and aluminum removal, two-stage iron and aluminum removal, one-stage nickel and cobalt precipitation, product filtration and two-stage nickel and cobalt precipitation in sequence, and the nickel sulfate solution and the high-pressure acid leaching solution are mixed in the pre-neutralization or the one-stage iron and aluminum removal stage; and / or, the nickel-iron acid leaching residue and the high-pressure acid leaching solution are mixed in the pre-neutralization stage.

4. The method according to claim 1, characterized in that The acid leaching temperature of nickel iron is controlled to be 20°C-90°C, the reaction pH value is 1.0-2.0, and the reaction time is 1h-10h.

5. The method according to claim 1 or 4, characterized in that: The process of preparing the nickel-iron acid leaching solution and the nickel-iron acid leaching residue includes: mixing nickel-iron powder and water to obtain nickel-iron slurry, mixing the nickel-iron slurry with phosphoric acid and sulfuric acid for acid leaching, then separating the solid and liquid and washing the obtained solid material.

6. The method according to claim 5, characterized in that When preparing the nickel-iron slurry, the liquid-solid mass ratio is controlled to be (3-15):1; Optionally, the molar ratio of the P content added to the phosphoric acid to the Fe content in the nickel-iron powder is (0.8-1.2):

1.

7. The method according to claim 5, characterized in that The nickel-iron powder is obtained by crushing a nickel-iron alloy. The composition of the nickel-iron alloy is as follows by mass percentage: Ni 5%-25%, Fe 60%-90%; the particle size of the nickel-iron powder is no more than 75 μm.

8. The method according to claim 1, characterized in that During the reaction of the nickel-iron acid leaching solution in the presence of an oxidant and a neutralizer, the reaction temperature is controlled to be 20°C-90°C, the reaction pH value is 0.5-2.5, and the reaction time is 1h-10h. The Fe content of the nickel sulfate solution obtained after the reaction is 2+ The concentration is not less than 0.01g / L.

9. The method according to claim 1 or 8, characterized in that: The oxidant is selected from at least one of hydrogen peroxide, oxygen, enriched oxygen and air.

10. The method according to claim 1 or 8, characterized in that: The neutralizing agent is selected from at least one of ammonia water, sodium hydroxide, potassium hydroxide, calcium hydroxide, calcium oxide, nickel oxide, nickel carbonate and nickel hydroxide.

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