Method for recycling laterite-nickel ore metallurgical slag resources

Abstract

The invention discloses a method for recycling laterite-nickel ore metallurgical slag resources, and belongs to the technical field of hydrometallurgy. The method comprises the following steps: carrying out alkaline leaching treatment on the laterite-nickel ore hydrometallurgical slag to obtain alkaline leaching liquid and alkaline leaching slag; carrying out acid leaching treatment on the alkaline leaching residues to obtain acid leaching liquid and acid leaching residues; mixing the acid leaching residues, a biomass reducing agent and an additive, performing primary ball milling treatment, and performing reduction roasting treatment on an obtained product to obtain a roasted product; and mixing the roasted product with a dispersing agent, carrying out secondary ball milling treatment, and carrying out magnetic separation on the obtained product to obtain iron ore concentrate. According to the method, the biomass is carbonized and activated to obtain the biomass reducing agent with enhanced reducibility, the biomass reducing agent is low in cost and environmentally friendly, the biomass reducing agent and the acid leaching residues are continuously mixed according to a specific proportion, reduction roasting is carried out under a specific atmosphere, and then magnetic separation is carried out; and iron ore concentrate with relatively high purity and yield is obtained.

Description

Technical Field

[0001] The present application belongs to the field of hydrometallurgy technology, and specifically relates to a method for recycling and utilizing laterite nickel ore metallurgical slag resources. Background Art

[0002] Nickel is a primary material in the production of new energy batteries. With the rapid development of the new energy industry, demand for nickel resources is constantly increasing. Currently, the hydrometallurgical extraction of nickel from laterite nickel ore has become a research hotspot. During this process, a large amount of laterite nickel ore metallurgical slag is generated.

[0003] At present, the treatment of laterite nickel ore metallurgical slag is mainly carried out through underground filter press backfill, deep-sea landfill and direct deep-sea discharge. However, due to the high iron content in laterite nickel ore metallurgical slag, direct landfill or discharge treatment will not only cause a large amount of iron resources to be wasted, but also cause environmental pollution because laterite nickel ore metallurgical slag also contains other harmful elements.

[0004] Therefore, it is urgent to propose a new processing method to solve the above problems existing in the prior art. Summary of the Invention

[0005] The purpose of this application is to provide a method for recycling and utilizing laterite nickel ore metallurgical slag resources. In this application, by sequentially subjecting laterite nickel ore hydrometallurgical slag to alkaline leaching, acid leaching, reduction roasting, and magnetic separation, not only an iron ore concentrate product but also sodium sulfate and calcium chloride products as by-products are obtained. Furthermore, the resulting non-magnetic material can be used to produce building materials or cement products. This method greatly improves the resource utilization rate of laterite nickel ore metallurgical slag and has good economic benefits.

[0006] The present application provides a method for recycling and utilizing laterite nickel ore metallurgical slag resources, comprising the following steps: subjecting the laterite nickel ore hydrometallurgical slag to alkali leaching to obtain an alkali leaching solution and an alkali leaching slag; subjecting the alkali leaching slag to acid leaching to obtain an acid leaching solution and an acid leaching slag; mixing the acid leaching slag, a biomass reducing agent, and an additive, subjecting the mixture to a primary ball milling treatment, and subjecting the obtained product to a reduction roasting treatment to obtain a roasted product; mixing the roasted product with a dispersant, subjecting the mixture to a secondary ball milling treatment, and subjecting the obtained product to magnetic separation to obtain an iron concentrate; wherein, in the preparation process of the roasted product, the biomass reducing agent is obtained by carbonizing and activating the biomass.

[0007] In the present application, the inventors have found that after alkaline leaching and acid leaching of laterite nickel ore hydrometallurgical slag, impurities in the laterite nickel ore hydrometallurgical slag can be removed. Furthermore, the biomass is carbonized (i.e., the process of converting the organic components of the biomass into inorganic carbon after high-temperature treatment) and activated (i.e., the carbonized product is treated so that its pore structure is regulated and improved) to obtain a biomass reducing agent with enhanced reducibility, which is beneficial to further improve the iron recovery effect. The present application uses carbon dioxide as an activating agent, and the process flow is relatively simple. The waste gas generated is CO2 and water vapor. The method is mainly based on the raw material of biomass reductant, which has little pollution to the environment. In addition, the final biochar product has a high specific surface area, a developed pore structure and a wide range of applications. The cost of the biomass reductant is low and the utilization rate of biomass is improved. After the biomass reductant is mixed with the acid leaching residue in a specific proportion, it is reduced and roasted in the presence of additives and a specific atmosphere and then magnetically separated to obtain iron concentrate with high purity. The recovery effect is equivalent to or even better than that of coal or other reducing agents (such as coke) prepared from coal as raw materials. In addition, the whole method has the advantages of short process, low cost and good recovery effect.

[0008] In some embodiments, during the preparation of the alkaline leachate and the alkaline leachate residue, the laterite nickel ore hydrometallurgical slag comprises the following components, calculated by mass percentage: 40-45% iron, 5-9% sulfur, 1.5-3% calcium, and 3-6% aluminum.

[0009] In the laterite nickel ore hydrometallurgical slag provided in the present application, Fe mainly exists in the form of Fe2O3, S and Ca mainly exist in the form of CaSO4, and Al mainly exists in the form of hydrated bauxite [(H2O)Al3(SO4)2(OH)6] and sodium aluminite [NaAl3(SO4)2(OH)6]; and the moisture content of the laterite nickel ore hydrometallurgical slag is 27-28%.

[0010] It should be noted that laterite nickel ore hydrometallurgical slag also contains other elements.

[0011] In some embodiments, in the preparation process of the alkaline leachate and the alkaline leachate slag, the alkaline leaching treatment step specifically includes: placing the laterite nickel ore hydrometallurgical slag in an alkaline solution, controlling the solid-liquid ratio to 1 g: (4-10) mL, and stirring for 60-140 min at a temperature of 60-90° C. and a rotation speed of 200-400 rpm; wherein the concentration of the alkaline solution is 1-2 mol / L, and the alkaline solution includes a NaOH solution and / or a Na2CO3 solution.

[0012] In the present application, the laterite nickel ore hydrometallurgical slag is subjected to an alkaline leaching treatment, so as to remove the sulfur impurity element in the laterite nickel ore hydrometallurgical slag.

[0013] In some embodiments, the preparation process of the alkaline leachate and the alkaline leachate residue further includes a step of evaporating and crystallizing the alkaline leachate to obtain a sodium sulfate product; wherein the evaporation and crystallization specifically includes: evaporating and crystallizing at a temperature of 75-95° C. for 160-200 minutes.

[0014] In the present application, the alkaline leaching solution is evaporated and crystallized, which can convert the sulfur impurity element into a by-product sodium sulfate product, further improving the resource utilization rate of the laterite nickel ore.

[0015] In some embodiments, during the preparation of the acid leachate and the acid leachate residue, the acid leaching treatment step specifically includes: placing the alkaline leaching residue in an acid solution, controlling the solid-liquid ratio to 1 g: (4-10) mL, and stirring for 60-140 min at a temperature of 60-90° C. and a rotation speed of 200-400 rpm; wherein the concentration of the acid solution is 1-2 mol / L, and the acid solution includes an HCl solution.

[0016] In the present application, the alkali leaching residue is subjected to acid leaching treatment to remove the calcium impurity element in the alkali leaching residue.

[0017] In some embodiments, the preparation process of the acid leachate and the acid leachate residue further includes a step of evaporating and crystallizing the acid leachate to obtain a calcium chloride product; wherein the evaporation and crystallization specifically includes: evaporating and crystallizing at a temperature of 30-90° C. for 160-200 minutes.

[0018] In the present application, the acid leaching solution is evaporated and crystallized, which can convert the calcium impurity element into a by-product calcium chloride product, further improving the resource utilization rate of the laterite nickel ore.

[0019] In some embodiments, during the preparation of the roasted product, the steps of carbonizing and activating the biomass specifically include: crushing the biomass, heating it to 350-600°C at a rate of 1-5°C / min under an inert atmosphere, and carbonizing it for 80-160 minutes; and further heating the resulting product to 350-600°C at a rate of 1-5°C / min under a carbon dioxide atmosphere, and activating it for 40-70 minutes; wherein the biomass includes at least one of coconut shells, wheat straw, corn straw, bamboo, rice straw, peanut shells, and tree branches, and the inert gas includes nitrogen and / or argon.

[0020] In the present application, a biomass reducing agent with enhanced reducing properties can be obtained by sequentially carbonizing and activating biomass, and the biomass raw material is easily available and environmentally friendly.

[0021] In some preferred embodiments, the method further comprises grinding, screening, removing impurities and drying the activated biomass to obtain a biomass reducing agent.

[0022] In some more preferred embodiments, grinding includes grinding using an agate mortar and / or a ball mill, the sieve has an aperture of 40-300 mesh, impurity removal includes rinsing with deionized water 3-5 times, and drying includes drying at a temperature of 110-120° C. for 680-800 minutes.

[0023] In the present application, the particle size of the biomass reducing agent is controlled within a specific range, the specific surface area is increased, and the activity of the biomass reducing agent is improved.

[0024] In some embodiments, during the preparation of the roasted product, the amount of the biomass reducing agent added is 2-5% of the mass of the acid leaching slag, and the additive is Na2CO3 and / or NaOH, and the amount of the additive added is 4-6% of the mass of the acid leaching slag; the first ball milling treatment step specifically includes: ball milling in a ball mill for 30-120 minutes; the reduction roasting treatment step specifically includes: placing the mixed material in an atmosphere furnace, while passing an inert gas at a flow rate of 1-5 mL / min; and heating to 500-900°C at a rate of 3-6°C / min and roasting for 30-180 minutes; wherein the inert gas is preferably argon. The present application can reduce the melting point and save energy by adding Na2CO3 and / or NaOH as additives during the roasting process, while facilitating the reaction of some substances in the slag to form sulfides, which is convenient for removal through the subsequent magnetic separation process, and ultimately further improving the purity of the iron ore concentrate; at the same time, the inventor found during the experiment that compared with nitrogen, using argon as an inert gas is more conducive to improving the purity of the iron ore concentrate.

[0025] In the present application, after a single ball milling treatment, on the one hand, the mixed materials are further mixed evenly, and at the same time, the particle size of the mixed materials is made smaller, which facilitates a sufficient reduction roasting reaction; further, by controlling the amount of the biomass reducing agent within a specific range and controlling the flow rate of the mixed gas, the acid leaching slag can be better reduced to obtain an iron concentrate with higher purity and yield.

[0026] In some embodiments, during the preparation of iron ore concentrate, the amount of dispersant added accounts for 3-5% of the mass of the roasted product, and the dispersant includes at least one of sodium metaphosphate, sodium hexametaphosphate, water glass, caustic starch and salted water glass (i.e., a mixture of water glass and aluminum sulfate); the secondary ball milling treatment step specifically includes: the ball milling time is 20-40 minutes.

[0027] In the present application, a dispersant is used to facilitate ball milling to obtain a mixture with a smaller particle size, and also to facilitate subsequent magnetic separation.

[0028] In some embodiments, during the preparation of iron ore concentrate, before the obtained product is subjected to magnetic separation, the steps of adding water to the obtained product for slurry adjustment to obtain an intermediate slurry, and magnetically separating the intermediate slurry are also included; wherein the mass of the added water is 4-6 times the mass of the obtained product; the magnetic separation specifically includes: performing magnetic separation under conditions of a magnetic separation intensity of 1000-3000Gs.

[0029] In the present application, magnetic separation is carried out at a specific magnetic separation intensity to obtain iron concentrate with higher purity.

[0030] In some preferred embodiments, the method further comprises the step of producing building materials and / or cement products from the non-magnetic substances obtained by magnetic separation.

[0031] The beneficial effects of the present application are as follows: different from the prior art, the present application can remove impurities in the laterite nickel ore hydrometallurgical slag after alkali leaching and acid leaching. Furthermore, the biomass is carbonized and activated to obtain a biomass reducing agent with enhanced reducibility. The cost of the biomass reducing agent is low and the utilization rate of the biomass is improved. After the biomass reducing agent is further mixed with the acid leaching slag in a specific proportion, it is reduced and roasted in the presence of additives and a specific atmosphere and then magnetically separated to obtain an iron concentrate with higher purity. In addition, the entire method has the advantages of short process, low cost, and good recovery effect, solves the environmental problems caused by long-term storage and landfill of laterite nickel ore hydrometallurgical slag, and is conducive to large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a flow chart of the method for recycling and utilizing laterite nickel ore metallurgical slag resources in this application. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0034] For experimental methods in the examples where specific conditions are not specified, generally conventional conditions and conditions described in the manual or conditions recommended by the manufacturer were followed. The general equipment, materials, reagents, etc. used were all commercially available unless otherwise specified.

[0035] See also Figure 1, which is a flow chart of the method for recycling and utilizing laterite nickel ore metallurgical slag resources in the present application. Specifically, the method includes the following steps: subjecting the laterite nickel ore hydrometallurgical slag to alkali leaching to obtain alkali leaching solution and alkali leaching slag, wherein the alkali leaching solution is evaporated and crystallized to obtain a sodium sulfate product; subjecting the alkali leaching slag to acid leaching to obtain acid leaching solution and acid leaching slag, wherein the acid leaching solution is evaporated and crystallized to obtain a calcium chloride product; mixing the acid leaching slag, a biomass reducing agent and an additive and performing a ball milling, and the obtained product is subjected to reduction roasting to obtain a roasted product; mixing the roasted product with a dispersant and performing a secondary ball milling, and the obtained product is subjected to magnetic separation to obtain iron concentrate and non-magnetic material, wherein the non-magnetic material is used to produce building materials or cement products.

[0036] In the present application, the moisture content of the laterite nickel ore hydrometallurgical slag is 27-28%, Fe mainly exists in the form of Fe2O3, S and Ca mainly exist in the form of CaSO4, and Al mainly exists in the form of hydrated bauxite [(H2O)Al3(SO4)2(OH)6] and sodium aluminite [NaAl3(SO4)2(OH)6]; the specific composition is shown in Table 1 below.

[0037] Table 1 Chemical composition of laterite nickel ore hydrometallurgical slag

[0038] Example 1 In this embodiment, a biomass reducing agent is first prepared, and the specific method is as follows: First, the coconut shell was crushed (less than 3 cm) using a crusher, then rinsed with deionized water to remove surface impurities, dried at 100°C for 480 min, and then carbonized at 500°C at a rate of 3°C / min under a nitrogen atmosphere for 80 min, and naturally cooled to room temperature. The resulting product was activated by heating to 500°C at a rate of 3°C / min under a carbon dioxide atmosphere for 40 min, and naturally cooled to room temperature. The activated biochar was crushed and ground with an agate mortar, passed through a 150-mesh sieve, rinsed four times with deionized water to remove impurities, and then dried at 110°C for 680 min to obtain a biomass reducing agent.

[0039] Then, the laterite nickel ore metallurgical slag resources are recycled, and the specific method includes the following steps: S1, the laterite nickel ore hydrometallurgical slag is placed in a NaOH solution with a concentration of 1.5 mol / L, and the solid-liquid ratio is controlled to be 1g: 7mL, and the temperature is 75 ° C. and the rotation speed is 300 rpm. Stir for 100min to obtain an alkaline leachate and an alkaline leached residue; the alkaline leachate is continued to be evaporated and crystallized at a temperature of 85 ° C. for 180min to obtain a sodium sulfate product; S2, placing the alkali leaching residue obtained in step S1 in a 1.5 mol / L HCl solution, controlling the solid-liquid ratio to 1 g:7 mL, stirring for 100 min at a temperature of 75 ° C and a rotation speed of 300 rpm to obtain an acid leaching solution and acid leaching residue; continuing to evaporate and crystallize the acid leaching solution at a temperature of 60 ° C for 180 min to obtain a calcium chloride product; S3, adding 2% of the mass of the biomass reducing agent and 4% of the mass of the acid leaching residue to the acid leaching residue obtained in step S2, mixing and uniformly ball milling in a ball mill for 80 min, then placing the ball-milled product in an atmosphere furnace, while introducing argon at a flow rate of 3 mL / min, and heating to 700 ° C at a rate of 5 ° C / min for reduction roasting for 100 min to obtain a roasted product; S4. Sodium metaphosphate accounting for 3% of the mass of the calcined product is added to the calcined product obtained in step S3, and the mixture is ball-milled for 30 minutes. Thereafter, slurry preparation is performed, and the amount of water added is 5 times the mass of the solid material to obtain an intermediate slurry. The intermediate slurry is then magnetically separated under a magnetic separation intensity of 2000 Gs, and the iron ore concentrate product and non-magnetic material are obtained after filtering and drying. The non-magnetic material is used to produce building materials or cement products.

[0040] Example 2 In this embodiment, a biomass reducing agent is first prepared, and the specific method is as follows: First, the fruit tree branches were crushed (less than 3 cm) using a crusher, then rinsed with deionized water to remove surface impurities, dried at 100°C for 480 min, and then carbonized at 500°C at a rate of 3°C / min under a nitrogen atmosphere for 100 min, and naturally cooled to room temperature. The resulting product was activated by heating to 500°C at a rate of 3°C / min under a carbon dioxide atmosphere for 50 min, and naturally cooled to room temperature. The activated biochar was crushed and ground with an agate mortar, passed through a 150-mesh sieve, rinsed four times with deionized water to remove impurities, and then dried at 115°C for 720 min to obtain a biomass reducing agent.

[0041] Then, the laterite nickel ore metallurgical slag resources are recycled, and the specific method includes the following steps: S1, the laterite nickel ore hydrometallurgical slag is placed in a NaOH solution with a concentration of 1.5 mol / L, and the solid-liquid ratio is controlled to be 1g: 7mL, and the temperature is 75 ° C. and the rotation speed is 300 rpm. Stir for 100min to obtain an alkaline leachate and an alkaline leached residue; the alkaline leachate is continued to be evaporated and crystallized at a temperature of 85 ° C. for 180min to obtain a sodium sulfate product; S2, placing the alkali leaching residue obtained in step S1 in a 1.5 mol / L HCl solution, controlling the solid-liquid ratio to 1 g:7 mL, stirring for 100 min at a temperature of 75 ° C and a rotation speed of 300 rpm to obtain an acid leaching solution and acid leaching residue; continuing to evaporate and crystallize the acid leaching solution at a temperature of 60 ° C for 180 min to obtain a calcium chloride product; S3, adding a biomass reducing agent accounting for 3% of the mass of the acid leaching residue and Na2CO3 accounting for 4% of the mass of the acid leaching residue to the acid leaching residue obtained in step S2, mixing and uniformly ball milling in a ball mill for 80 minutes, then placing the ball-milled product in an atmosphere furnace, while passing argon at a flow rate of 3 mL / min; and heating to 700°C at a rate of 5°C / min and reducing and roasting for 100 minutes to obtain a roasted product; S4. Add 4% of sodium metaphosphate by mass to the calcined product obtained in step S3, mix and ball-mill for 30 minutes, then perform slurry preparation, and add water in an amount of 5 times the mass of the solid material to obtain an intermediate slurry, and then perform magnetic separation on the intermediate slurry under the condition of a magnetic separation intensity of 2000 Gs, filter and dry to obtain an iron ore concentrate product and a non-magnetic substance, which is used to produce building materials or cement products.

[0042] Example 3 In this embodiment, a biomass reducing agent is first prepared, and the specific method is as follows: First, the coconut shell was crushed (less than 3 cm) using a crusher, then rinsed with deionized water to remove surface impurities, dried at 100°C for 480 min, and then carbonized at 500°C at a rate of 3°C / min under a nitrogen atmosphere for 120 min, and naturally cooled to room temperature. The resulting product was activated by heating to 500°C at a rate of 3°C / min under a carbon dioxide atmosphere for 60 min, and naturally cooled to room temperature. The activated biochar was crushed and ground with an agate mortar, passed through a 150-mesh sieve, rinsed four times with deionized water to remove impurities, and then dried at 117°C for 720 min to obtain a biomass reducing agent.

[0043] Then, the laterite nickel ore metallurgical slag resources are recycled, and the specific method includes the following steps: S1. The laterite nickel ore wet smelting slag is placed in a NaOH solution with a concentration of 2 mol / L, and the solid-liquid ratio is controlled to be 1 g:7 mL. The mixture is stirred for 100 min at a temperature of 75 ° C and a rotation speed of 300 rpm to obtain an alkali leachate and an alkali leachate slag; the alkali leachate is evaporated and crystallized at a temperature of 85 ° C for 180 min to obtain a sodium sulfate product; S2, placing the alkali leaching residue obtained in step S1 in a 1.5 mol / L HCl solution, controlling the solid-liquid ratio to 1 g:7 mL, stirring for 100 min at a temperature of 75 ° C and a rotation speed of 300 rpm to obtain an acid leaching solution and acid leaching residue; continuing to evaporate and crystallize the acid leaching solution at a temperature of 60 ° C for 180 min to obtain a calcium chloride product; S3, adding 4% of the mass of the biomass reducing agent and 4% of the mass of the acid leaching residue to the acid leaching residue obtained in step S2, and evenly ball milling the mixture in a ball mill for 80 minutes. Then, the ball-milled product was placed in an atmosphere furnace, and argon was introduced at a flow rate of 3 mL / min; and the temperature was raised to 700° C. at a rate of 5° C. / min, and reduction roasted for 100 minutes to obtain a roasted product; S4. Add 4% of sodium metaphosphate by mass to the calcined product obtained in step S3, mix and ball-mill for 30 minutes, then perform slurry preparation, and add water in an amount of 5 times the mass of the solid material to obtain an intermediate slurry, and then perform magnetic separation on the intermediate slurry under the condition of a magnetic separation intensity of 2000 Gs, filter and dry to obtain an iron ore concentrate product and a non-magnetic substance, which is used to produce building materials or cement products.

[0044] Example 4 In this embodiment, a biomass reducing agent is first prepared, and the specific method is as follows: First, the coconut shell was crushed (less than 3 cm) using a crusher, then rinsed with deionized water to remove surface impurities, dried at 100°C for 480 min, and then carbonized at 500°C at a rate of 3°C / min under a nitrogen atmosphere for 160 min, and naturally cooled to room temperature. The resulting product was activated by heating to 500°C at a rate of 3°C / min under a carbon dioxide atmosphere for 70 min, and naturally cooled to room temperature. The activated biochar was crushed and ground in an agate mortar, passed through a 150-mesh sieve, rinsed four times with deionized water to remove impurities, and then dried at 120°C for 800 min to obtain a biomass reducing agent.

[0045] Then, the laterite nickel ore metallurgical slag resources are recycled, and the specific method includes the following steps: S1, the laterite nickel ore wet smelting slag is placed in a Na2CO3 solution with a concentration of 1.5 mol / L, and the solid-liquid ratio is controlled to be 1 g: 7 mL, and stirred for 100 min at a temperature of 75 ° C and a rotation speed of 300 rpm to obtain an alkali leachate and an alkali leachate slag; the alkali leachate is continued to be evaporated and crystallized at a temperature of 85 ° C for 180 min to obtain a sodium sulfate product; S2, placing the alkali leaching residue obtained in step S1 in a 1.5 mol / L HCl solution, controlling the solid-liquid ratio to 1 g:7 mL, stirring for 100 min at a temperature of 75 ° C and a rotation speed of 300 rpm to obtain an acid leaching solution and acid leaching residue; continuing to evaporate and crystallize the acid leaching solution at a temperature of 60 ° C for 180 min to obtain a calcium chloride product; S3, adding a biomass reducing agent accounting for 5% of the mass of the acid leaching residue and Na2CO3 accounting for 6% of the mass of the acid leaching residue to the acid leaching residue obtained in step S2, mixing and uniformly ball milling in a ball mill for 80 minutes, then placing the ball-milled product in an atmosphere furnace, while passing argon at a flow rate of 3 mL / min; and heating to 700°C at a rate of 5°C / min and reducing and roasting for 100 minutes to obtain a roasted product; S4. Add 5% of the mass of sodium metaphosphate to the calcined product obtained in step S3, mix and ball mill for 30 minutes, then perform slurry preparation, and add water in an amount of 5 times the mass of the solid material to obtain an intermediate slurry, and then magnetically separate the intermediate slurry under a magnetic separation intensity of 2000 Gs, filter and dry to obtain an iron ore concentrate product and a non-magnetic substance, which is used to produce building materials or cement products.

[0046] Comparative Example 1 The method for recycling laterite nickel ore metallurgical slag resources in this comparative example is basically the same as that in Example 1, except that in step S3, the amount of biomass reducing agent added accounts for 0.5% of the mass of the acid leaching slag.

[0047] Comparative Example 2 The method for recycling the laterite nickel ore metallurgical slag resources in this comparative example is basically the same as that in Example 1, except that the laterite nickel ore hydrometallurgical slag is not subjected to the treatment in steps S1 and S2, and is directly subjected to the treatment in steps S3 and S4.

[0048] The yield and purity of the iron concentrate recovered in Examples 1-4 and Comparative Examples 1-2 were tested, and the results are shown in Table 2.

[0049] Table 2 Yield and purity of iron ore concentrate

[0050] As can be seen from the data in Table 2, Examples 1-4 employed the methods of this application to recycle laterite nickel ore metallurgical slag resources, yielding high-purity iron ore concentrate products. In Comparative Example 1, the amount of biomass reductant added was reduced, resulting in a significant decrease in the purity of the iron ore concentrate. This indicates that controlling the amount of biomass reductant added within a specific range can improve the purity of the iron ore concentrate. In Comparative Example 2, the laterite nickel ore hydrometallurgical slag was not subjected to alkaline and acid leaching, resulting in a significant decrease in the purity of the iron ore concentrate. This indicates that impurities can be removed through alkaline and acid leaching, which can improve the purity of the iron ore concentrate.

[0051] In summary, in this application, by sequentially subjecting laterite nickel ore hydrometallurgical slag to alkaline leaching, acid leaching, reduction roasting, and magnetic separation, not only an iron ore concentrate product can be obtained, but also a by-product sodium sulfate product and calcium chloride product can be obtained, and the resulting non-magnetic material can be used to produce building materials or cement products. This method greatly improves the resource utilization rate of laterite nickel ore metallurgical slag.

[0052] It should be noted that the above embodiments all belong to the same inventive concept, and the description of each embodiment has its own focus. For any details not described in individual embodiments, reference may be made to the description in other embodiments.

[0053] The above-described embodiments merely represent implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A method for recycling laterite nickel ore metallurgical slag resources, characterized in that: The steps include: performing alkaline leaching on laterite nickel ore hydrometallurgical slag to obtain alkaline leaching solution and alkaline leaching slag; performing acid leaching on the alkali leaching residue to obtain acid leaching solution and acid leaching residue; The acid leaching residue, the biomass reducing agent and the additive are mixed and subjected to a ball milling process, and the obtained product is subjected to a reduction roasting process to obtain a roasted product; The calcined product is mixed with a dispersant and subjected to a secondary ball milling process, and the obtained product is subjected to magnetic separation to obtain an iron concentrate; Wherein, in the preparation process of the roasted product, the biomass reducing agent is obtained by carbonizing and activating the biomass.

2. The method for recycling laterite nickel ore metallurgical slag resources according to claim 1, characterized in that: In the preparation process of the alkaline leaching solution and the alkaline leaching slag, the laterite nickel ore hydrometallurgical slag includes the following components, calculated by mass percentage: 40-45% iron, 5-9% sulfur, 1.5-3% calcium and 3-6% aluminum.

3. The method for recycling laterite nickel ore metallurgical slag resources according to claim 1, characterized in that: In the preparation process of the alkaline leaching solution and the alkaline leaching residue, the alkaline leaching treatment step specifically includes: placing the laterite nickel ore hydrometallurgical slag in an alkaline solution, controlling the solid-liquid ratio to be 1g:(4-10)mL, and stirring for 60-140min at a temperature of 60-90°C and a rotation speed of 200-400rpm; Wherein, the concentration of the alkali solution is 1-2 mol / L, and the alkali solution includes NaOH solution and / or Na2CO3 solution.

4. The method for recycling laterite nickel ore metallurgical slag resources according to claim 1, characterized in that: The preparation process of the alkaline leachate and the alkaline leachate residue further includes the step of evaporating and crystallizing the alkaline leachate to obtain a sodium sulfate product; The evaporation crystallization specifically includes: evaporation crystallization for 160-200 minutes at a temperature of 75-95°C.

5. The method for recycling laterite nickel ore metallurgical slag resources according to claim 1, characterized in that: In the process of preparing the acid leaching solution and the acid leaching residue, the acid leaching treatment step specifically includes: placing the alkaline leaching residue in an acid solution, controlling the solid-liquid ratio to be 1g:(4-10)mL, and stirring for 60-140min at a temperature of 60-90°C and a rotation speed of 200-400rpm; The concentration of the acid solution is 1-2 mol / L, and the acid solution includes HCl solution.

6. The method for recycling laterite nickel ore metallurgical slag resources according to claim 1, characterized in that: The process for preparing the acid leaching solution and the acid leaching residue further includes the step of evaporating and crystallizing the acid leaching solution to obtain a calcium chloride product; The evaporation crystallization specifically includes: evaporation crystallization for 160-200 minutes at a temperature of 30-90°C.

7. The method for recycling laterite nickel ore metallurgical slag resources according to claim 1, characterized in that: In the preparation process of the roasted product, the steps of carbonizing and activating the biomass specifically include: crushing the biomass, heating it to 350-600°C at a rate of 1-5°C / min under an inert atmosphere, and carbonizing it for 80-160 minutes; and further heating the resulting product to 350-600°C at a rate of 1-5°C / min under a carbon dioxide atmosphere, and activating it for 40-70 minutes; The biomass includes at least one of coconut shells, wheat straw, corn straw, bamboo, rice straw, peanut shells, and tree branches, and the inert gas includes nitrogen and / or argon.

8. The method for recycling laterite nickel ore metallurgical slag resources according to claim 1, characterized in that: During the preparation of the roasted product, the amount of the biomass reducing agent added is 2-5% of the mass of the acid leaching residue, and the additive is Na2CO3 and / or NaOH, and the amount of the additive added is 4-6% of the mass of the acid leaching residue; The one-time ball milling step specifically comprises: ball milling in a ball mill for 30-120 minutes; The reduction roasting treatment step specifically includes: placing the mixed material in an atmosphere furnace, while introducing an inert gas at a flow rate of 1-5 mL / min; and heating to 500-900° C. at a rate of 3-6° C. / min and roasting for 30-180 minutes; Wherein, the inert gas includes argon.

9. The method for recycling laterite nickel ore metallurgical slag resources according to claim 1, characterized in that: During the preparation of the iron ore concentrate, the amount of the dispersant added accounts for 3-5% of the mass of the roasted product, and the dispersant includes at least one of sodium metaphosphate, sodium hexametaphosphate, water glass, caustic starch and salted water glass; The secondary ball milling step specifically includes: the ball milling time is 20-40 minutes.

10. The method for recycling laterite nickel ore metallurgical slag resources according to claim 1, characterized in that: In the preparation process of the iron ore concentrate, before the obtained product is subjected to magnetic separation, the process further includes adding water to the obtained product for slurrying treatment to obtain an intermediate slurry, and subjecting the intermediate slurry to magnetic separation; The mass of water added is 4-6 times the mass of the obtained product; and the magnetic separation specifically includes: performing magnetic separation under the condition of a magnetic separation intensity of 1000-3000 Gs.

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