Method for recycling laterite-nickel ore metallurgical slag resources

Abstract

The invention relates to a method for recycling laterite-nickel ore metallurgical slag resources, which comprises the following steps: sequentially carrying out alkaline leaching treatment and acid leaching treatment on laterite-nickel ore metallurgical slag to remove impurities, and further carbonizing and activating biomass to obtain a biomass reducing agent with enhanced reducibility, thereby being beneficial to further improving the recovery effect of iron. The biomass reducing agent is relatively low in cost, and meanwhile, the utilization rate of biomass is increased; and after the biomass reducing agent and the acid leaching slag are continuously mixed, reduction roasting and magnetic separation are carried out, so that iron ore concentrate with relatively high purity and yield is obtained, a byproduct sodium sulfate product and a byproduct calcium chloride product can be recovered at the same time, and the resource utilization rate of the laterite-nickel ore metallurgical slag is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, and in particular to a method for recycling laterite nickel ore metallurgical slag resources. Background Art

[0002] Nickel is the main material for the preparation of new energy batteries. With the rapid development of the new energy industry, the demand for nickel resources is also increasing. At present, the process of hydrometallurgical extraction of nickel from laterite nickel ore has become a research hotspot. In the process of hydrometallurgical extraction of nickel from laterite nickel ore, a large amount of laterite nickel ore metallurgical slag will be produced.

[0003] At present, the treatment of laterite nickel ore metallurgical slag is mainly carried out through underground filter pressure backfilling, 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 waste of iron resources, but also cause environmental pollution due to the presence of other harmful elements in laterite nickel ore metallurgical slag.

[0004] CN102146511A discloses a process for recovering nickel and iron from laterite nickel ore by selective reduction roasting, which specifically comprises the following steps: first, crushing a certain amount of silicate laterite nickel ore to a particle size of -10mm, adding 10-20% of a reducing agent and 5-15% of a flux, and then mixing them evenly, then adding the above-mentioned evenly mixed raw materials into a muffle furnace, roasting them at a temperature of 1100-1150°C for 40-80 minutes, adding them into a ball mill for grinding after natural cooling, obtaining a slurry with a mass concentration of 60% and a grinding particle size of -0.074mm accounting for 85-95%, placing the slurry under a magnetic field strength of 150-200kA / m for magnetic separation, obtaining nickel and iron metals, and a nickel recovery rate of more than 80%. However, the method provided by the invention inhibits the recovery of iron and also causes a certain waste of resources.

[0005] CN117066519A discloses a process for recovering iron from laterite nickel ore hydrometallurgical tailings, which comprises the following steps: S10: uniformly mixing laterite nickel ore hydrometallurgical tailings with a certain proportion of reducing agent to obtain a mixed material; and drying the laterite nickel ore hydrometallurgical tailings before and / or after mixing with the reducing agent; S20: performing high-temperature reduction roasting on the mixed material to obtain reduced roasted sand; wherein the temperature of the reduction roasting is 900-1200°C, and the time of the reduction roasting is 0.5-5 hours; S30: crushing and grinding the reduced roasted sand; S40: performing magnetic separation on the ground reduced roasted sand to obtain reduced iron powder. The roasting temperature used in this method is relatively high, the energy consumption is increased, and the by-products cannot be recycled and utilized as resources. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for recycling laterite nickel ore metallurgical slag resources, which can not only obtain iron concentrate products, but also obtain by-product sodium sulfate products and calcium chloride products, greatly improving the resource utilization rate of laterite nickel ore metallurgical slag and having good economic benefits.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for recycling laterite nickel ore metallurgical slag resources, the method comprising the following steps:

[0009] (1) performing alkaline leaching on the laterite nickel ore metallurgical slag to obtain an alkaline leaching solution and an alkaline leaching slag; performing a first evaporation crystallization on the obtained alkaline leaching solution to obtain a sodium sulfate product; performing an acid leaching on the obtained alkaline leaching slag to obtain an acid leaching solution and an acid leaching slag; performing a second evaporation crystallization on the obtained acid leaching solution to obtain a calcium chloride product;

[0010] (2) mixing the biomass reducing agent, the additive and the acid leaching residue obtained in step (1) and subjecting the mixture to a primary ball milling treatment, subjecting the primary ball milling product to a reduction roasting treatment to obtain a roasting product; mixing the roasting product with a dispersant and subjecting the mixture to a secondary ball milling treatment, subjecting the secondary ball milling product to magnetic separation to obtain an iron concentrate;

[0011] The biomass reducing agent in step (2) is obtained by subjecting the biomass to carbonization treatment and activation treatment in sequence.

[0012] The method for recycling and utilizing laterite nickel ore metallurgical slag resources provided by the present invention can remove impurities in the laterite nickel ore metallurgical slag after alkali leaching treatment and acid leaching treatment are performed on the laterite nickel ore metallurgical slag in sequence, and further, the biomass is carbonized, and the organic components of the biomass are converted into inorganic carbon after high-temperature treatment, and then the biomass is activated to regulate and improve its pore structure, and the finally obtained biomass reducing agent with enhanced reducibility is conducive to further improving the iron recovery effect, and the cost of the biomass reducing agent is low, and the utilization rate of the biomass is improved at the same time; after the biomass reducing agent is further mixed with the acid leaching slag in a specific ratio, the iron concentrate with high purity and yield is obtained after reduction roasting with additives and a specific atmosphere, and magnetic separation is performed, and the recovery effect is equivalent to or even better than that of coal or other reducing agents prepared with coal as raw materials; in addition, the whole method has the advantages of short process, low cost, good recovery effect, etc.

[0013] Preferably, the laterite nickel ore metallurgical slag in step (1) comprises the following components in percentage by mass: 40-45% iron, 5-9% sulfur, 1.5-6% calcium, and 2.5-6% aluminum.

[0014] The mass percentage of iron in the components of the laterite nickel ore metallurgical slag is 40-45%, for example, it can be 40%, 41.11%, 42%, 43% or 45%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] The mass percentage of sulfur in the components of the laterite nickel ore metallurgical slag is 5-9%, for example, it can be 5%, 6%, 7.07%, 8% or 9%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] The mass percentage of calcium in the components of the laterite nickel ore metallurgical slag is 1.5-6%, for example, it can be 1.5%, 2%, 3%, 5.3% or 6%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0017] The mass percentage of aluminum in the components of the laterite nickel ore metallurgical slag is 2.5-6%, for example, it can be 2.5%, 2.86%, 4%, 5% or 6%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] In the laterite nickel ore metallurgical slag provided by the present invention, 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 water content of the laterite nickel ore metallurgical slag is 27-28%. It should be noted that the laterite nickel ore metallurgical slag also contains other elements.

[0019] Preferably, the concentration of the alkali solution used for the alkali leaching treatment in step (1) is 1-2 mol / L, for example, it can be 1 mol / L, 1.2 mol / L, 1.5 mol / L, 1.8 mol / L or 2 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0020] Preferably, the alkali solution comprises sodium hydroxide solution and / or sodium carbonate solution.

[0021] In the present invention, the laterite nickel ore metallurgical slag is subjected to alkali leaching treatment, so as to remove the sulfur impurity element in the laterite nickel ore metallurgical slag.

[0022] Preferably, the solid-to-liquid ratio of the alkali leaching treatment in step (1) is 1g:(4-10)mL, for example, it can be 1g:4mL, 1g:5mL, 1g:6mL, 1g:8mL or 1g:10mL, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0023] Preferably, the temperature of the alkali leaching treatment in step (1) is 60-90°C, for example, 60°C, 70°C, 75°C, 80°C or 90°C, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 70-80°C.

[0024] Preferably, the rotation speed of the alkali leaching treatment in step (1) is 200-400 rpm, for example, it can be 200 rpm, 250 rpm, 300 rpm, 350 rpm or 400 rpm, but is not limited to the listed values. Other values ​​not listed in the numerical range are also applicable, preferably 250-350 rpm.

[0025] Preferably, the alkali leaching treatment time in step (1) is 60-140 min, for example, 60 min, 80 min, 100 min, 120 min or 140 min, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 80-120 min.

[0026] Preferably, in step (1), the temperature of the first evaporation crystallization is 75-95° C. and the time is 160-200 min.

[0027] The temperature of the first evaporation crystallization is 75-95°C, for example, 75°C, 80°C, 85°C, 90°C or 95°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0028] The time of the first evaporation crystallization is 160-200 min, for example, 160 min, 170 min, 180 min, 190 min or 200 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] In the present invention, the acid leaching solution is evaporated and crystallized, so that the calcium impurity element can be converted into a by-product calcium chloride product, thereby further improving the resource utilization rate of the laterite nickel ore.

[0030] Preferably, the concentration of the acid solution used for the acid leaching treatment in step (1) is 1-2 mol / L, for example, it can be 1 mol / L, 1.2 mol / L, 1.5 mol / L, 1.8 mol / L or 2 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0031] Preferably, the acid solution used for the acid leaching treatment in step (1) comprises a hydrochloric acid solution.

[0032] Preferably, the solid-to-liquid ratio of the acid leaching treatment in step (1) is 1g:(4-10)mL, for example, it can be 1g:4mL, 1g:5mL, 1g:6mL, 1g:8mL or 1g:10mL, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0033] Preferably, the temperature of the acid leaching treatment in step (1) is 60-90°C, for example, 60°C, 70°C, 75°C, 80°C or 90°C, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 70-80°C.

[0034] Preferably, the rotation speed of the acid leaching treatment in step (1) is 200-400 rpm, for example, it can be 200 rpm, 250 rpm, 300 rpm, 350 rpm or 400 rpm, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 250-350 rpm.

[0035] Preferably, the acid leaching time in step (1) is 60-140 min, for example, 60 min, 80 min, 100 min, 120 min or 140 min, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 80-120 min.

[0036] Preferably, the temperature of the second evaporation crystallization in step (1) is 30-90° C. and the time is 160-200 min.

[0037] The temperature of the second evaporation crystallization is 30-90°C, for example, 30°C, 40°C, 50°C, 70°C or 90°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0038] The time of the second evaporation crystallization is 160-200 min, for example, 160 min, 170 min, 180 min, 190 min or 200 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0039] Preferably, the biomass comprises at least one of coconut shells, wheat straws, corn straws, bamboo, rice straws, peanut shells or fruit tree branches, preferably coconut shells and / or fruit tree branches.

[0040] Preferably, the carbonization treatment includes a step of pulverizing the biomass.

[0041] Preferably, the carbonization treatment is performed under an inert atmosphere.

[0042] Preferably, the inert atmosphere comprises nitrogen and / or argon.

[0043] Preferably, the heating rate of the carbonization treatment is 1-5°C / min, for example, it can be 1°C / min, 2°C / min, 3°C / min, 4°C / min or 5°C / min, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 2-4°C / min.

[0044] Preferably, the temperature of the carbonization treatment is 350-700°C, for example, 350°C, 400°C, 450°C, 500°C or 600°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 400-600°C.

[0045] Preferably, the carbonization treatment time is 80-160 min, for example, 80 min, 100 min, 110 min, 120 min or 160 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 100-120 min.

[0046] Preferably, the activation treatment is performed under a carbon dioxide atmosphere.

[0047] The present invention uses carbon dioxide as an activating agent, has a relatively simple process flow, generates waste gas mainly composed of carbon dioxide and water vapor, has little pollution to the environment, and the final biomass reducing agent product has a high specific surface area, a developed pore structure, and a wide range of applications.

[0048] Preferably, the heating rate of the activation treatment is 1-5°C / min, for example, 1°C / min, 2°C / min, 3°C / min, 4°C / min or 5°C / min, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 2-4°C / min.

[0049] Preferably, the temperature of the activation treatment is 350-600°C, for example, 350°C, 400°C, 450°C, 550°C or 600°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 400-550°C.

[0050] Preferably, the activation treatment time is 40-70 min, for example, 40 min, 50 min, 55 min, 60 min or 70 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 50-60 min.

[0051] In the present invention, the biomass reducing agent with enhanced reducing property can be obtained by sequentially subjecting the biomass to carbonization and activation treatment, and the biomass raw material is easily available and environmentally friendly.

[0052] Preferably, the activation treatment further includes the steps of grinding, screening, removing impurities and drying the activated biomass.

[0053] Preferably, the grinding is performed using an agate mortar and / or a ball mill.

[0054] Preferably, the mesh size of the sieve is 40-300 mesh, for example, 40 mesh, 80 mesh, 150 mesh, 200 mesh or 300 mesh, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0055] In the present invention, 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.

[0056] Preferably, the impurity removal comprises rinsing with deionized water for 3-5 times, for example, 3 times, 4 times or 5 times.

[0057] Preferably, the drying temperature is 110-120°C, for example, 110°C, 112°C, 115°C, 118°C or 120°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0058] Preferably, the drying time is 680-800 min, for example, 680 min, 700 min, 720 min, 750 min or 800 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0059] Preferably, the amount of the additive added in step (2) is 4-6wt% of the mass of the acid leaching slag, for example, it can be 4wt%, 4.5wt%, 5wt%, 5.5wt% or 6wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0060] Preferably, the additive in step (2) comprises sodium carbonate and / or sodium hydroxide.

[0061] The present invention can reduce the melting point and save energy consumption by adding sodium carbonate and / or sodium hydroxide as additives during the roasting process, and is conducive to the reaction of some substances in the slag to generate sulfides, which are convenient for removal through the subsequent magnetic separation process, and finally further improve the purity of the iron ore concentrate.

[0062] Preferably, the amount of the biomass reducing agent added in step (2) is 2-5wt% of the mass of the acid leaching slag, for example, it can be 2wt%, 3wt%, 3.5wt%, 4wt% or 5wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 3-4wt%.

[0063] Preferably, the time of the ball milling treatment in step (2) is 30-120 min, for example, 30 min, 50 min, 80 min, 100 min or 120 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0064] In the present invention, after the first ball milling treatment, the mixed materials are further mixed evenly, and at the same time, the particle size of the mixed materials is made smaller, which is convenient for the reduction roasting reaction to be sufficient.

[0065] Preferably, the reduction calcination step in step (2) specifically comprises: heating to 500-900° C. at a rate of 3-6° C. / min under an inert atmosphere, and calcining for 30-180 min.

[0066] The heating rate is 3-6°C / min, for example, 3°C / min, 4°C / min, 5°C / min or 6°C / min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0067] The end point of the heating temperature is 500-900°C, for example, 500°C, 600°C, 700°C, 800°C or 900°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0068] The calcination time is 30-180 min, for example, 30 min, 60 min, 100 min, 150 min or 180 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0069] Preferably, the flow rate of the inert atmosphere is 1-5 mL / min, for example, 1 mL / min, 2 mL / min, 3 mL / min, 4 mL / min or 5 mL / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0070] The invention can reduce the acid leaching slag better and obtain the iron concentrate with higher purity and yield by controlling the dosage of the biomass reducing agent within a specific range and controlling the flow rate of the inert atmosphere.

[0071] Preferably, the inert atmosphere comprises argon.

[0072] Compared with nitrogen, using argon as an inert gas is more conducive to improving the purity of iron ore concentrate.

[0073] Preferably, the amount of the dispersant added in step (2) is 3-5wt% of the mass of the calcined product, for example, it can be 3wt%, 3.5wt%, 4wt%, 4.5wt% or 5wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0074] Preferably, the dispersant in step (2) includes at least one of sodium metaphosphate, sodium hexametaphosphate, water glass, caustic starch or salted water glass.

[0075] The "salted water glass" refers to a mixture of water glass and aluminum sulfate.

[0076] In the present invention, the use of a dispersant facilitates ball milling to obtain a mixture with a smaller particle size, and is also convenient for subsequent magnetic separation.

[0077] Preferably, the time of the secondary ball milling treatment in step (2) is 20-40 min, for example, 20 min, 25 min, 30 min, 35 min or 40 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0078] Preferably, before the magnetic separation in step (2), the method further comprises adding water to the secondary ball milling product to perform slurry treatment to obtain an intermediate slurry.

[0079] Preferably, the amount of water added in the slurry adjustment treatment is 4-6 times the mass of the secondary ball-milled product obtained, for example, it can be 4 times, 5 times or 6 times, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0080] Preferably, the magnetic separation intensity of the magnetic separation in step (2) is 1000-3000 Gs, for example, it can be 1000 Gs, 1500 Gs, 2000 Gs, 2500 Gs or 3000 Gs, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 1500-2500 Gs.

[0081] In the present invention, magnetic separation is carried out under a specific magnetic separation intensity to obtain iron concentrate with higher purity.

[0082] Preferably, the non-magnetic material obtained by magnetic separation is used to produce building materials.

[0083] As a preferred technical solution of the method of the present invention, the method comprises the following steps:

[0084] (1) performing alkaline leaching on laterite nickel ore metallurgical slag, wherein the concentration of the alkaline solution used is 1-2 mol / L, the solid-liquid ratio is 1 g:(4-10) mL, the temperature is 60-90° C., the rotation speed is 200-400 rpm, and the time is 60-140 min to obtain an alkaline leaching solution and an alkaline leaching slag; the obtained alkaline leaching solution is subjected to a first evaporation crystallization at 75-95° C. for 160-200 min to obtain a sodium sulfate product; the laterite nickel ore metallurgical slag comprises the following components in mass percentage: 40-45% iron, 5-9% sulfur, 1.5-6% calcium, and 2.5-6% aluminum;

[0085] The obtained alkaline leaching residue is subjected to acid leaching treatment, wherein the concentration of the used acid solution is 1-2 mol / L, the solid-liquid ratio is 1 g:(4-10) mL, the temperature is 60-90° C., the rotation speed is 200-400 rpm, and the time is 60-140 min to obtain an acid leaching solution and acid leaching residue; the obtained acid leaching solution is subjected to a second evaporation crystallization at 30-90° C. for 160-200 min to obtain a calcium chloride product;

[0086] (2) The biomass reducing agent, the additive and the acid leaching residue obtained in step (1) are mixed and subjected to a primary ball milling treatment for 30-120 min. The primary ball milling product is heated to 500-900° C. at a rate of 3-6° C. / min in an inert atmosphere with a flow rate of 1-5 mL / min, and roasted for 30-180 min to obtain a roasted product; the roasted product is mixed with a dispersant and subjected to a secondary ball milling treatment for 20-40 min. Water is added to the secondary ball milling product for slurry adjustment, and the amount of water added is 4-6 times the mass of the secondary ball milling product; the intermediate slurry is subjected to magnetic separation at a magnetic separation intensity of 1000-3000 Gs to obtain an iron concentrate;

[0087] The amount of the additive added is 4-6wt% of the mass of the acid leaching slag; the amount of the biomass reducing agent added is 2-5wt% of the mass of the acid leaching slag; the amount of the dispersant added is 3-5wt% of the mass of the roasting product;

[0088] The biomass reducing agent is obtained by crushing biomass and then sequentially performing carbonization treatment, activation treatment, grinding, sieving through a 40-300 mesh sieve, removing impurities and drying; the carbonization treatment is carried out under an inert atmosphere, the heating rate of the carbonization treatment is 1-5°C / min, the temperature is 350-600°C, and the time is 80-160min; the activation treatment is carried out under a carbon dioxide atmosphere, the heating rate of the activation treatment is 1-5°C / min, the temperature is 350-600°C, and the time is 40-70min.

[0089] Compared with the prior art, the present invention has the following beneficial effects:

[0090] The method for recycling and utilizing laterite-nickel ore metallurgical slag resources provided by the present invention can remove impurities in the laterite-nickel ore metallurgical slag after sequentially subjecting the laterite-nickel ore metallurgical slag to alkali leaching treatment and acid leaching treatment, further subjecting the biomass to carbonization and activation treatment to obtain a biomass reducing agent with enhanced reducibility, which is beneficial to further improving the iron recovery effect, and the cost of the biomass reducing agent is low, while improving the utilization rate of the biomass; after further mixing the biomass reducing agent with the acid leaching slag in a specific ratio, performing reduction roasting under an additive and a specific atmosphere, and then performing magnetic separation, so as to obtain an iron concentrate with high purity and yield; in addition, the whole method has the advantages of short process, low cost, good recycling effect, etc., and can also simultaneously recover by-product sodium sulfate products and calcium chloride products, thereby greatly improving the resource utilization rate of the laterite-nickel ore metallurgical slag, solving the environmental problems caused by long-term storage and landfill of the laterite-nickel ore metallurgical slag, and being beneficial to large-scale promotion and application. DETAILED DESCRIPTION

[0091] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0092] The experimental methods without specific conditions in the examples are usually carried out according to conventional conditions and conditions described in the manual, or according to conditions recommended by the manufacturer. The general equipment, materials, reagents, etc. used are all available from commercial channels unless otherwise specified.

[0093] The present invention provides a method for recycling laterite nickel ore metallurgical slag resources, the method comprising the following steps:

[0094] (1) performing alkaline leaching on the laterite nickel ore metallurgical slag to obtain an alkaline leaching solution and an alkaline leaching slag; performing a first evaporation crystallization on the obtained alkaline leaching solution to obtain a sodium sulfate product; performing an acid leaching on the obtained alkaline leaching slag to obtain an acid leaching solution and an acid leaching slag; performing a second evaporation crystallization on the obtained acid leaching solution to obtain a calcium chloride product;

[0095] (2) The biomass reducing agent, additives and the acid leaching residue obtained in step (1) are mixed and subjected to a primary ball milling treatment, and the primary ball milling product is subjected to a reduction roasting treatment to obtain a roasting product; the roasting product is mixed with a dispersant and subjected to a secondary ball milling treatment, and the secondary ball milling product is subjected to magnetic separation to obtain iron ore concentrate and non-magnetic substances, wherein the non-magnetic substances are used to produce building materials; the biomass reducing agent in step (2) is obtained by subjecting the biomass to a carbonization treatment and an activation treatment in sequence.

[0096] In the laterite nickel ore metallurgical slag provided by the present invention, 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 water content of the laterite nickel ore metallurgical slag is 27-28%. The specific components are shown in Table 1 below.

[0097] Table 1

[0098]

[0099] Example 1

[0100] This embodiment provides a method for recycling laterite nickel ore metallurgical slag resources, the method comprising the following steps:

[0101] (1) performing alkali leaching on laterite nickel ore metallurgical slag, wherein the alkali solution used is a sodium hydroxide solution with a concentration of 1.5 mol / L, a solid-liquid ratio of 1 g:6 mL, a temperature of 75° C., a rotation speed of 300 rpm, and a time of 100 min to obtain an alkali leaching solution and an alkali leaching slag; the obtained alkali leaching solution is subjected to a first evaporation crystallization at 85° C. for 180 min to obtain a sodium sulfate product;

[0102] The obtained alkaline leaching residue is subjected to acid leaching treatment, the acid solution used is a hydrochloric acid solution with a concentration of 1.5 mol / L, a solid-liquid ratio of 1 g:6 mL, a temperature of 75° C., a rotation speed of 300 rpm, and a time of 100 min to obtain an acid leaching solution and acid leaching residue; the obtained acid leaching solution is subjected to a second evaporation crystallization at 50° C. for 180 min to obtain a calcium chloride product;

[0103] (2) crushing the coconut shell to less than 3 cm, then washing with deionized water to remove surface impurities, drying at 100° C. for 480 min, and then sequentially performing carbonization treatment, activation treatment, ball mill grinding, 150-mesh sieve, deionized water washing 4 times to remove impurities and drying at 115° C. for 750 min to obtain a biomass reducing agent; the carbonization treatment is carried out in an argon atmosphere, the heating rate of the carbonization treatment is 3° C. / min, the temperature is 450° C., and the time is 110 min; the activation treatment is carried out in a carbon dioxide atmosphere, the heating rate of the activation treatment is 3° C. / min, the temperature is 500° C., and the time is 55 min;

[0104] Then, the obtained biomass reducing agent, sodium carbonate and the acid leaching slag obtained in step (1) are mixed and subjected to a ball milling treatment for 80 minutes, wherein the amount of sodium carbonate added is 5wt% of the mass of the acid leaching slag, and the amount of the biomass reducing agent added is 3.5wt% of the mass of the acid leaching slag; the obtained primary ball milling product is heated to 700°C at a rate of 4°C / min under an argon atmosphere with a flow rate of 3mL / min, and roasted for 100min to obtain a roasting product; the obtained roasting product is mixed with sodium metaphosphate and subjected to a secondary ball milling treatment for 30min, wherein the amount of sodium metaphosphate added is 4wt% of the mass of the roasting product; water is added to the obtained secondary ball milling product for slurry adjustment, and the amount of water added is 5 times the mass of the obtained secondary ball milling product; the obtained intermediate slurry is magnetically separated at a magnetic separation intensity of 2000Gs to obtain iron concentrate and non-magnetic material, and the non-magnetic material is used to produce building materials.

[0105] Example 2

[0106] This embodiment provides a method for recycling laterite nickel ore metallurgical slag resources, the method comprising the following steps:

[0107] (1) performing alkali leaching on laterite nickel ore metallurgical slag, wherein the alkali solution used is a sodium hydroxide solution with a concentration of 1 mol / L, a solid-liquid ratio of 1 g:4 mL, a temperature of 70° C., a rotation speed of 250 rpm, and a time of 120 min to obtain an alkali leaching solution and an alkali leaching slag; the obtained alkali leaching solution is subjected to a first evaporation crystallization at 75° C. for 200 min to obtain a sodium sulfate product;

[0108] The obtained alkaline leaching residue is subjected to acid leaching treatment, the acid solution used is a hydrochloric acid solution with a concentration of 1 mol / L, a solid-liquid ratio of 1 g:4 mL, a temperature of 70° C., a rotation speed of 250 rpm, and a time of 120 min to obtain an acid leaching solution and acid leaching residue; the obtained acid leaching solution is subjected to a second evaporation crystallization at 30° C. for 200 min to obtain a calcium chloride product;

[0109] (2) crushing the coconut shell to less than 3 cm, then washing with deionized water to remove surface impurities, drying at 100° C. for 480 min, and then sequentially performing carbonization treatment, activation treatment, ball mill grinding, 40-mesh sieve, deionized water washing 3 times to remove impurities and drying at 110° C. for 800 min to obtain a biomass reducing agent; the carbonization treatment is carried out in a nitrogen atmosphere, the heating rate of the carbonization treatment is 2° C. / min, the temperature is 400° C., and the time is 120 min; the activation treatment is carried out in a carbon dioxide atmosphere, the heating rate of the activation treatment is 2° C. / min, the temperature is 400° C., and the time is 60 min;

[0110] Then, the obtained biomass reducing agent, sodium carbonate and the acid leaching slag obtained in step (1) are mixed and subjected to a ball milling treatment for 30 minutes, wherein the amount of sodium carbonate added is 4wt% of the mass of the acid leaching slag, and the amount of the biomass reducing agent added is 3wt% of the mass of the acid leaching slag; the obtained primary ball milling product is heated to 500°C at a rate of 3°C / min under an argon atmosphere with a flow rate of 1mL / min, and roasted for 180min to obtain a roasting product; the obtained roasting product is mixed with sodium hexametaphosphate and subjected to a secondary ball milling treatment for 20min, wherein the amount of sodium hexametaphosphate added is 3wt% of the mass of the roasting product; water is added to the obtained secondary ball milling product for slurry adjustment, and the amount of water added is 4 times the mass of the obtained secondary ball milling product; the obtained intermediate slurry is magnetically separated at a magnetic separation intensity of 1500Gs to obtain iron concentrate and non-magnetic material, and the non-magnetic material is used to produce building materials.

[0111] Example 3

[0112] This embodiment provides a method for recycling laterite nickel ore metallurgical slag resources, the method comprising the following steps:

[0113] (1) performing alkali leaching on laterite nickel ore metallurgical slag, wherein the alkali solution used is a sodium hydroxide solution with a concentration of 2 mol / L, a solid-liquid ratio of 1 g:10 mL, a temperature of 80° C., a rotation speed of 350 rpm, and a time of 80 min to obtain an alkali leaching solution and an alkali leaching slag; the obtained alkali leaching solution is subjected to a first evaporation crystallization at 95° C. for 160 min to obtain a sodium sulfate product;

[0114] The obtained alkaline leaching residue is subjected to acid leaching treatment, the acid solution used is a hydrochloric acid solution with a concentration of 2 mol / L, a solid-liquid ratio of 1 g:10 mL, a temperature of 80° C., a rotation speed of 350 rpm, and a time of 80 min to obtain an acid leaching solution and acid leaching residue; the obtained acid leaching solution is subjected to a second evaporation crystallization at 90° C. for 160 min to obtain a calcium chloride product;

[0115] (2) crushing the branches of the fruit tree to less than 3 cm, then washing with deionized water to remove surface impurities, drying at 100°C for 480 min, and then sequentially performing carbonization treatment, activation treatment, ball mill grinding, 300-mesh sieve, deionized water washing for 5 times to remove impurities, and drying at 120°C for 680 min to obtain a biomass reducing agent; the carbonization treatment is carried out in an argon atmosphere, the heating rate of the carbonization treatment is 4°C / min, the temperature is 500°C, and the time is 100 min; the activation treatment is carried out in a carbon dioxide atmosphere, the heating rate of the activation treatment is 4°C / min, the temperature is 550°C, and the time is 50 min;

[0116] Then, the obtained biomass reducing agent, sodium hydroxide and the acid leaching slag obtained in step (1) are mixed and subjected to a primary ball milling treatment for 120 minutes, wherein the amount of the sodium hydroxide added is 6wt% of the mass of the acid leaching slag, and the amount of the biomass reducing agent added is 4wt% of the mass of the acid leaching slag; the obtained primary ball milling product is heated to 900°C at a rate of 6°C / min under an argon atmosphere with a flow rate of 5mL / min, and roasted for 30min to obtain a roasting product; the obtained roasting product is mixed with water glass and subjected to a secondary ball milling treatment for 40min, wherein the amount of the water glass added is 5wt% of the mass of the roasting product; water is added to the obtained secondary ball milling product for slurry adjustment, and the amount of water added is 6 times the mass of the obtained secondary ball milling product; the obtained intermediate slurry is magnetically separated at a magnetic separation intensity of 2500Gs to obtain iron concentrate and non-magnetic material, and the non-magnetic material is used to produce building materials.

[0117] Example 4

[0118] This embodiment provides a method for recycling laterite nickel ore metallurgical slag resources, the method comprising the following steps:

[0119] (1) performing alkali leaching on laterite nickel ore metallurgical slag, wherein the alkali solution used is a sodium carbonate solution with a concentration of 1 mol / L, a solid-liquid ratio of 1 g:4 mL, a temperature of 60° C., a rotation speed of 200 rpm, and a time of 140 min to obtain an alkali leaching solution and an alkali leaching slag; the obtained alkali leaching solution is subjected to a first evaporation crystallization at 75° C. for 200 min to obtain a sodium sulfate product;

[0120] The obtained alkaline leaching residue is subjected to acid leaching treatment, the acid solution used is a hydrochloric acid solution with a concentration of 1 mol / L, a solid-liquid ratio of 1 g:4 mL, a temperature of 60° C., a rotation speed of 200 rpm, and a time of 140 min to obtain an acid leaching solution and acid leaching residue; the obtained acid leaching solution is subjected to a second evaporation crystallization at 30° C. for 200 min to obtain a calcium chloride product;

[0121] (2) The wheat straw was crushed to less than 3 cm, then rinsed with deionized water to remove surface impurities, dried at 100°C for 480 min, and then carbonized, activated, ball milled, sieved through a 40-mesh sieve, rinsed with deionized water for 3 times to remove impurities, and dried at 110°C for 800 min to obtain a biomass reducing agent; the carbonization treatment was carried out in a nitrogen atmosphere, the heating rate of the carbonization treatment was 1°C / min, the temperature was 350°C, and the time was 160 min; the activation treatment was carried out in a carbon dioxide atmosphere, the heating rate of the activation treatment was 1°C / min, the temperature was 350°C, and the time was 70 min;

[0122] Then, the obtained biomass reducing agent, sodium carbonate and the acid leaching residue obtained in step (1) are mixed and subjected to a ball milling treatment for 30 minutes, wherein the amount of sodium carbonate added is 4wt% of the mass of the acid leaching residue, and the amount of the biomass reducing agent added is 2wt% of the mass of the acid leaching residue; the obtained primary ball milling product is heated to 500°C at a rate of 3°C / min under an argon atmosphere with a flow rate of 1mL / min, and roasted for 180min to obtain a roasting product; the obtained roasting product is mixed with caustic starch and subjected to a secondary ball milling treatment for 20min, wherein the amount of caustic starch added is 3wt% of the mass of the roasting product; water is added to the obtained secondary ball milling product for slurry adjustment, and the amount of water added is 4 times the mass of the obtained secondary ball milling product; the obtained intermediate slurry is magnetically separated at a magnetic separation intensity of 1000Gs to obtain iron concentrate and non-magnetic material, and the non-magnetic material is used to produce building materials.

[0123] Example 5

[0124] This embodiment provides a method for recycling laterite nickel ore metallurgical slag resources, the method comprising the following steps:

[0125] (1) performing alkali leaching on laterite nickel ore metallurgical slag, wherein the alkali solution used is a sodium hydroxide solution with a concentration of 2 mol / L, a solid-liquid ratio of 1 g:10 mL, a temperature of 90° C., a rotation speed of 400 rpm, and a time of 60 min to obtain an alkali leaching solution and an alkali leaching slag; the obtained alkali leaching solution is subjected to a first evaporation crystallization at 95° C. for 160 min to obtain a sodium sulfate product;

[0126] The obtained alkaline leaching residue is subjected to acid leaching treatment, the acid solution used is a hydrochloric acid solution with a concentration of 2 mol / L, a solid-liquid ratio of 1 g:10 mL, a temperature of 90° C., a rotation speed of 400 rpm, and a time of 60 min to obtain an acid leaching solution and acid leaching residue; the obtained acid leaching solution is subjected to a second evaporation crystallization at 90° C. for 160 min to obtain a calcium chloride product;

[0127] (2) The bamboo was crushed to less than 3 cm, and then rinsed with deionized water to remove surface impurities, dried at 100°C for 480 min, and then carbonized, activated, ball milled, sieved through a 300-mesh sieve, rinsed with deionized water for 5 times to remove impurities, and dried at 120°C for 680 min to obtain a biomass reducing agent; the carbonization treatment was carried out in an argon atmosphere, the heating rate of the carbonization treatment was 5°C / min, the temperature was 600°C, and the time was 80 min; the activation treatment was carried out in a carbon dioxide atmosphere, the heating rate of the activation treatment was 5°C / min, the temperature was 600°C, and the time was 40 min;

[0128] Then, the obtained biomass reducing agent, sodium hydroxide and the acid leaching slag obtained in step (1) are mixed and subjected to a primary ball milling treatment for 120 minutes, wherein the amount of the sodium hydroxide added is 6wt% of the mass of the acid leaching slag, and the amount of the biomass reducing agent added is 5wt% of the mass of the acid leaching slag; the obtained primary ball milling product is heated to 900°C at a rate of 6°C / min under an argon atmosphere with a flow rate of 5mL / min, and roasted for 30min to obtain a roasting product; the obtained roasting product is mixed with salted water glass and subjected to a secondary ball milling treatment for 40min, wherein the amount of the salted water glass added is 5wt% of the mass of the roasting product; water is added to the obtained secondary ball milling product for slurry adjustment, and the amount of water added is 6 times the mass of the obtained secondary ball milling product; the obtained intermediate slurry is magnetically separated at a magnetic separation intensity of 3000Gs to obtain iron concentrate and non-magnetic material, and the non-magnetic material is used to produce building materials.

[0129] Example 6

[0130] This embodiment provides a method for recycling laterite nickel ore metallurgical slag resources. The difference from Example 1 is that except that the temperature of the alkali leaching treatment in step (1) is adjusted to 50° C., the rest is the same as Example 1.

[0131] Example 7

[0132] This embodiment provides a method for recycling laterite nickel ore metallurgical slag resources. The difference from Example 1 is that except that the temperature of the alkali leaching treatment in step (1) is adjusted to 100° C., the rest is the same as Example 1.

[0133] Example 8

[0134] This embodiment provides a method for recycling laterite nickel ore metallurgical slag resources. The difference from Example 1 is that except for adjusting the rotation speed of the acid leaching treatment in step (1) to 150 rpm, the rest is the same as Example 1.

[0135] Example 9

[0136] This embodiment provides a method for recycling laterite nickel ore metallurgical slag resources. The difference from Example 1 is that except for adjusting the rotation speed of the acid leaching treatment in step (1) to 450 rpm, the rest is the same as Example 1.

[0137] Example 10

[0138] This embodiment provides a method for recycling laterite nickel ore metallurgical slag resources. The difference from Embodiment 1 is that there is no ball mill grinding and 150-mesh sieve step after the activation treatment in step (2), and the rest is the same as Embodiment 1.

[0139] Embodiment 11

[0140] This embodiment provides a method for recycling laterite nickel ore metallurgical slag resources. The difference from Example 1 is that, except for adjusting the amount of the biomass reducing agent added in step (2) to 0.5wt% of the mass of the acid leaching slag, the rest is the same as Example 1.

[0141] Example 12

[0142] This embodiment provides a method for recycling laterite nickel ore metallurgical slag resources. The difference from Example 1 is that, except for adjusting the amount of the biomass reducing agent added in step (2) to 6wt% of the mass of the acid leaching slag, the rest is the same as Example 1.

[0143] Example 13

[0144] This embodiment provides a method for recycling laterite nickel ore metallurgical slag resources. The difference from Example 1 is that, except for adjusting the magnetic separation intensity of the magnetic separation in step (2) to 800 Gs, the rest is the same as Example 1.

[0145] Embodiment 14

[0146] This embodiment provides a method for recycling laterite nickel ore metallurgical slag resources. The difference from Example 1 is that, except for adjusting the magnetic separation intensity of the magnetic separation in step (2) to 3300 Gs, the rest is the same as Example 1.

[0147] Comparative Example 1

[0148] This comparative example provides a method for recycling laterite nickel ore metallurgical slag resources, which differs from Example 1 in that step (1) is omitted, and in step (2), the quality of acid leaching slag is replaced by laterite nickel ore metallurgical slag, and the rest is the same as Example 1.

[0149] Comparative Example 2

[0150] This comparative example provides a method for recycling and utilizing laterite nickel ore metallurgical slag resources, which differs from Example 1 in that in step (1), the laterite nickel ore metallurgical slag is first subjected to acid leaching treatment, and the obtained acid leaching slag is subjected to alkali leaching treatment, and in step (2), the obtained alkali leaching slag is subjected to a ball milling treatment, and the rest is the same as Example 1.

[0151] Comparative Example 3

[0152] This comparative example provides a method for recycling and utilizing laterite nickel ore metallurgical slag resources, which differs from Example 1 in that there is no acid leaching treatment in step (1), and the rest is the same as Example 1.

[0153] Comparative Example 4

[0154] This comparative example provides a method for recycling and utilizing laterite nickel ore metallurgical slag resources, which differs from Example 1 in that no alkali leaching treatment is performed in step (1), and the rest is the same as Example 1.

[0155] The yield and purity of the iron concentrate recovered in Examples 1-14 and Comparative Examples 1-4 were tested, and the calculation method was: yield: (mass of the target substance after magnetic separation / initial mass of the laterite nickel ore metallurgical slag)*100%; purity: (mass of the target substance after magnetic separation / mass of the substance after magnetic separation)*100%. The results are shown in Table 2.

[0156] Table 2

[0157] Yield (%) purity(%) Example 1 63.44 67.37 Example 2 64.86 64.97 Example 3 63.23 67.01 Example 4 62.21 64.05 Example 5 61.84 63.87 Example 6 62.52 63.38 Example 7 62.06 63.23 Example 8 61.51 62.84 Example 9 62.93 61.57 Example 10 62.25 62.83 Embodiment 11 70.72 60.22 Example 12 63.27 64.60 Example 13 60.54 62.96 Embodiment 14 73.98 60.06 Comparative Example 1 68.50 60.13 Comparative Example 2 66.71 61.72 Comparative Example 3 68.32 60.96 Comparative Example 4 67.84 60.73

[0158] From the data in Table 2, it can be seen that the purity of the iron concentrate products obtained in Examples 4 and 5 is slightly reduced compared with Examples 1-3, indicating that each parameter is within the preferred range, which is conducive to obtaining an iron concentrate with higher purity; from the comparison of Examples 6-9 with Example 1, it can be seen that the temperature and rotation speed of the alkali leaching treatment and the acid leaching treatment need to be controlled within a reasonable range. Exceeding the limited range will reduce the purity or yield of the iron concentrate product; from the comparison of Example 10 with Example 1, it can be seen that the biomass is not ground and screened after activation treatment, and the particle size of the biomass reducing agent is too large, which reduces the activity of the biomass reducing agent, thereby reducing the yield of the iron concentrate product; from the comparison of Examples 11 and 12 with Example 1, it can be seen that the amount of the biomass reducing agent is too low, the purity of the iron concentrate product is significantly reduced, and the amount is too high, The cost of raw materials will increase, and the purity and yield of the iron concentrate product will no longer increase significantly; from the comparison of Examples 13 and 14 with Example 1, it can be seen that the magnetic separation intensity is too high, the purity of the iron concentrate product is significantly reduced, and the magnetic separation intensity is too low, The yield of the iron concentrate product is significantly reduced.

[0159] By comparing Comparative Examples 1-4 with Example 1, it can be seen that when the laterite nickel ore metallurgical slag is not subjected to alkali leaching and acid leaching, or is first subjected to acid leaching and then to alkali leaching, or is subjected to a single acid leaching or alkali leaching treatment, the purity of the iron ore concentrate product is significantly reduced.

[0160] In summary, the method for recycling and utilizing laterite-nickel ore metallurgical slag resources provided by the present invention can remove impurities in the laterite-nickel ore metallurgical slag after alkali leaching and acid leaching are performed on the laterite-nickel ore metallurgical slag in sequence, and further obtain a biomass reducing agent with enhanced reducibility after carbonizing and activating the biomass, which is beneficial to further improve the iron recovery effect, and the cost of the biomass reducing agent is low, and the utilization rate of the biomass is improved at the same time; after continuing to mix the biomass reducing agent with the acid leaching slag in a specific ratio, the biomass reducing agent is reduced and roasted under an additive and a specific atmosphere, and then magnetic separation is performed to obtain an iron concentrate with high purity and yield; in addition, the whole method has the advantages of short process, low cost, good recovery effect, etc., and can also simultaneously recover by-product sodium sulfate products and calcium chloride products, which greatly improves the resource utilization rate of the laterite-nickel ore metallurgical slag, solves the environmental problems caused by long-term storage and landfill of the laterite-nickel ore metallurgical slag, and is beneficial to large-scale promotion and application.

[0161] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for recycling laterite nickel ore metallurgical slag resources, characterized in that: The method comprises the following steps: (1) performing alkaline leaching on the laterite nickel ore metallurgical slag to obtain an alkaline leaching solution and an alkaline leaching slag; performing a first evaporation crystallization on the obtained alkaline leaching solution to obtain a sodium sulfate product; performing an acid leaching on the obtained alkaline leaching slag to obtain an acid leaching solution and an acid leaching slag; performing a second evaporation crystallization on the obtained acid leaching solution to obtain a calcium chloride product; (2) mixing the biomass reducing agent, the additive and the acid leaching residue obtained in step (1) and subjecting the mixture to a primary ball milling treatment, subjecting the primary ball milling product to a reduction roasting treatment to obtain a roasting product; mixing the roasting product with a dispersant and subjecting the mixture to a secondary ball milling treatment, subjecting the secondary ball milling product to magnetic separation to obtain an iron concentrate; The biomass reducing agent in step (2) is obtained by subjecting the biomass to carbonization treatment and activation treatment in sequence.

2. The method according to claim 1, characterized in that In terms of mass percentage, the laterite nickel ore metallurgical slag in step (1) comprises the following components: 40-45% iron, 5-9% sulfur, 1.5-6% calcium, and 2.5-6% aluminum; Preferably, the concentration of the alkali solution used in the alkali leaching treatment in step (1) is 1-2 mol / L; Preferably, the alkali solution comprises sodium hydroxide solution and / or sodium carbonate solution; Preferably, the solid-to-liquid ratio of the alkali leaching treatment in step (1) is 1 g: (4-10) mL; Preferably, the temperature of the alkali leaching treatment in step (1) is 60-90°C, preferably 70-80°C; Preferably, the rotation speed of the alkali leaching treatment in step (1) is 200-400 rpm, preferably 250-350 rpm; Preferably, the alkali leaching treatment time in step (1) is 60-140 min, preferably 80-120 min; Preferably, in step (1), the temperature of the first evaporation crystallization is 75-95° C. and the time is 160-200 min.

3. The method according to claim 1 or 2, characterized in that: The concentration of the acid solution used in the acid leaching treatment in step (1) is 1-2 mol / L; Preferably, the acid solution used for the acid leaching treatment in step (1) comprises a hydrochloric acid solution; Preferably, the solid-to-liquid ratio of the acid leaching treatment in step (1) is 1 g: (4-10) mL; Preferably, the temperature of the acid leaching treatment in step (1) is 60-90°C, preferably 70-80°C; Preferably, the rotation speed of the acid leaching treatment in step (1) is 200-400 rpm, preferably 250-350 rpm; Preferably, the acid leaching treatment time in step (1) is 60-140 min, preferably 80-120 min; Preferably, the temperature of the second evaporation crystallization in step (1) is 30-90° C. and the time is 160-200 min.

4. The method according to any one of claims 1 to 3, characterized in that: The biomass comprises at least one of coconut shell, wheat straw, corn straw, bamboo, rice straw, peanut shell or fruit tree branch, preferably coconut shell and / or fruit tree branch; Preferably, the carbonization treatment includes a step of pulverizing the biomass; Preferably, the carbonization treatment is carried out under an inert atmosphere; Preferably, the inert atmosphere comprises nitrogen and / or argon; Preferably, the heating rate of the carbonization treatment is 1-5°C / min, preferably 2-4°C / min; Preferably, the temperature of the carbonization treatment is 350-600°C, preferably 400-500°C; Preferably, the carbonization treatment time is 80-160 min, preferably 100-120 min.

5. The method according to any one of claims 1 to 4, characterized in that: The activation treatment is carried out under a carbon dioxide atmosphere; Preferably, the heating rate of the activation treatment is 1-5°C / min, preferably 2-4°C / min; Preferably, the temperature of the activation treatment is 350-600°C, preferably 400-550°C; Preferably, the activation treatment time is 40-70 min, preferably 50-60 min; Preferably, the activation treatment further comprises the steps of grinding, screening, removing impurities and drying the activated biomass; Preferably, the mesh size of the sieve is 40-300 meshes.

6. The method according to any one of claims 1 to 5, characterized in that: The amount of the additive added in step (2) is 4-6wt% of the mass of the acid leaching residue; Preferably, the additive in step (2) comprises sodium carbonate and / or sodium hydroxide; Preferably, the amount of the biomass reducing agent added in step (2) is 2-5wt% of the mass of the acid leaching residue, preferably 3-4wt%; Preferably, the time for the ball milling treatment in step (2) is 30-120 min.

7. The method according to any one of claims 1 to 6, characterized in that: The reduction calcination step in step (2) specifically comprises: heating to 500-900° C. at a rate of 3-6° C. / min under an inert atmosphere, and calcining for 30-180 min; Preferably, the flow rate of the inert atmosphere is 1-5 mL / min; Preferably, the inert atmosphere comprises argon.

8. The method according to any one of claims 1 to 7, characterized in that: The amount of the dispersant added in step (2) is 3-5wt% of the mass of the calcined product; Preferably, the dispersant in step (2) comprises at least one of sodium metaphosphate, sodium hexametaphosphate, water glass, caustic starch or salted water glass; Preferably, the time for the secondary ball milling treatment in step (2) is 20-40 minutes.

9. The method according to any one of claims 1 to 8, characterized in that: Before the magnetic separation in step (2), the method further includes adding water to the secondary ball milling product to prepare a slurry to obtain an intermediate slurry; Preferably, the amount of water added in the slurry adjustment treatment is 4-6 times the mass of the secondary ball milling product obtained; Preferably, the magnetic separation intensity of the magnetic separation in step (2) is 1000-3000 Gs, preferably 1500-2500 Gs.

10. The method according to claim 1, characterized in that The method comprises the following steps: (1) performing alkaline leaching on laterite nickel ore metallurgical slag, wherein the concentration of the alkaline solution used is 1-2 mol / L, the solid-liquid ratio is 1 g:(4-10) mL, the temperature is 60-90° C., the rotation speed is 200-400 rpm, and the time is 60-140 min to obtain an alkaline leaching solution and an alkaline leaching slag; the obtained alkaline leaching solution is subjected to a first evaporation crystallization at 75-95° C. for 160-200 min to obtain a sodium sulfate product; the laterite nickel ore metallurgical slag comprises the following components in mass percentage: 40-45% iron, 5-9% sulfur, 1.5-6% calcium, and 2.5-6% aluminum; The obtained alkaline leaching residue is subjected to acid leaching treatment, wherein the concentration of the used acid solution is 1-2 mol / L, the solid-liquid ratio is 1 g:(4-10) mL, the temperature is 60-90° C., the rotation speed is 200-400 rpm, and the time is 60-140 min to obtain an acid leaching solution and acid leaching residue; the obtained acid leaching solution is subjected to a second evaporation crystallization at 30-90° C. for 160-200 min to obtain a calcium chloride product; (2) The biomass reducing agent, the additive and the acid leaching residue obtained in step (1) are mixed and subjected to a primary ball milling treatment for 30-120 min. The primary ball milling product is heated to 500-900° C. at a rate of 3-6° C. / min in an inert atmosphere with a flow rate of 1-5 mL / min, and roasted for 30-180 min to obtain a roasted product; the roasted product is mixed with a dispersant and subjected to a secondary ball milling treatment for 20-40 min. Water is added to the secondary ball milling product for slurry adjustment, and the amount of water added is 4-6 times the mass of the secondary ball milling product; the intermediate slurry is subjected to magnetic separation at a magnetic separation intensity of 1000-3000 Gs to obtain an iron concentrate; The amount of the additive added is 4-6wt% of the mass of the acid leaching slag; the amount of the biomass reducing agent added is 2-5wt% of the mass of the acid leaching slag; the amount of the dispersant added is 3-5wt% of the mass of the roasting product; The biomass reducing agent is obtained by crushing biomass and then sequentially performing carbonization treatment, activation treatment, grinding, sieving through a 40-300 mesh sieve, removing impurities and drying; the carbonization treatment is carried out under an inert atmosphere, the heating rate of the carbonization treatment is 1-5°C / min, the temperature is 350-600°C, and the time is 80-160min; the activation treatment is carried out under a carbon dioxide atmosphere, the heating rate of the activation treatment is 1-5°C / min, the temperature is 350-600°C, and the time is 40-70min.

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