A method for recycling and utilizing laterite nickel ore metallurgical slag resources

Abstract

The present application relates to a kind of laterite nickel ore metallurgical slag resource recycling method, by sequentially carrying out alkali leaching treatment and acid leaching treatment to laterite nickel ore metallurgical slag to remove impurities, further the biomass is carbonized and activated to obtain the biomass reducing agent with enhanced reducing property, which is beneficial to further improve the recovery effect of iron, and the cost of the biomass reducing agent is relatively low, while improving the utilization rate of biomass;Continue to mix the biomass reducing agent with acid leaching residue, and then carry out reduction roasting and magnetic separation, thereby obtaining high-purity and high-yield iron concentrate, and simultaneously recovering by-product sodium sulfate product and calcium chloride product, greatly improving the resource utilization rate of laterite nickel ore metallurgical slag.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrometallurgy, in particular to a method for recycling and utilizing laterite nickel ore metallurgical slag. BACKGROUND

[0002] Nickel is a main material for preparing new energy batteries. With the rapid development of the new energy industry, the demand for nickel resources is also rising. At present, the process of extracting nickel from laterite nickel ore by hydrometallurgy has become a research hotspot. In the process of extracting nickel from laterite nickel ore by hydrometallurgy, a large amount of laterite nickel ore metallurgical slag is produced.

[0003] At present, the treatment of laterite nickel ore metallurgical slag is mainly through underground pressure filtration backfill, deep sea landfill and deep sea direct discharge and the like. However, due to the high iron content in the laterite nickel ore metallurgical slag, if direct landfill or discharge treatment is performed, not only will a large amount of iron resources be wasted, but also the environment will be polluted due to the presence of other harmful elements in the laterite nickel ore metallurgical slag.

[0004] CN102146511A discloses a process for selectively recovering nickel and iron from laterite nickel ore by reduction roasting, which specifically comprises the following steps: first, a certain amount of silicate laterite nickel ore is crushed to a particle size of -10 mm, 10-20% of a reducing agent and 5-15% of a fluxing agent are added, and then the mixture is uniformly mixed, then the uniformly mixed raw material is added to a muffle furnace and roasted at a temperature of 1100-1150℃ for 40-80 minutes, after natural cooling, the material is added to a ball mill for grinding, a slurry with a mass concentration of 60% and a grinding particle size of -0.074 mm accounting for 85-95% is obtained, the slurry is placed in a magnetic field with a magnetic field intensity of 150-200kA / m for magnetic separation, and nickel and iron metals are obtained, and the recovery rate of nickel is more than 80%. However, the method provided by the present application inhibits the recovery of iron, which also causes a certain waste of resources.

[0005] CN117066519A discloses a process for recovering iron from laterite nickel ore hydrometallurgy tailings, which comprises the following steps: S10: uniformly mixing the laterite nickel ore hydrometallurgy tailings with a certain proportion of a reducing agent to obtain a mixture; and before and / or after mixing the laterite nickel ore hydrometallurgy tailings with the reducing agent, the laterite nickel ore hydrometallurgy tailings are subjected to drying treatment; S20: high-temperature reduction roasting of the mixture to obtain a reduction roasting sand; wherein the temperature of the reduction roasting is 900-1200℃, and the time of the reduction roasting is 0.5-5 hours; S30: crushing and finely grinding the reduction roasting sand; S40: magnetic separation of the finely ground reduction roasting sand to obtain a reduction iron powder. The method uses a high roasting temperature, which increases energy consumption, and the by-products cannot be recycled and utilized. SUMMARY

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide a method for recycling red soil 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 red soil nickel ore metallurgical slag and having good economic benefits.

[0007] To achieve the purpose of the present application, the following technical solutions are adopted:

[0008] The present application provides a method for recycling red soil nickel ore metallurgical slag resources, which comprises the following steps:

[0009] (1) The red soil nickel ore metallurgical slag is subjected to alkali leaching treatment to obtain alkali leaching solution and alkali leaching residue; the obtained alkali leaching solution is subjected to first evaporation crystallization to obtain sodium sulfate products; the obtained alkali leaching residue is subjected to acid leaching treatment to obtain acid leaching solution and acid leaching residue; the obtained acid leaching solution is subjected to second evaporation crystallization to obtain calcium chloride products;

[0010] (2) The biomass reducing agent, the additive and the acid leaching residue obtained in step (1) are mixed and subjected to primary ball milling treatment, and the obtained primary ball milling product is subjected to reduction roasting treatment to obtain a roasting product; the obtained roasting product is mixed with a dispersing agent and subjected to secondary ball milling treatment, and the obtained secondary ball milling product is subjected to magnetic separation to obtain iron concentrate;

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

[0012] The method for recycling red soil nickel ore metallurgical slag resources provided by the present application can remove impurities in the red soil nickel ore metallurgical slag after sequentially subjecting the red soil nickel ore metallurgical slag to alkali leaching treatment and acid leaching treatment. Further, the biomass is subjected to carbonization treatment, and the organic components of the biomass are converted into inorganic carbon after high-temperature treatment, and then the biomass is subjected to activation treatment to regulate and improve the pore structure thereof. Finally, the obtained biomass reducing agent has enhanced reducing property, which is beneficial to further improving the iron recovery effect, and the cost of the biomass reducing agent is relatively low, and the utilization rate of the biomass is improved. The biomass reducing agent is mixed with the acid leaching residue in a specific proportion, and then subjected to reduction roasting in the presence of an additive and a specific atmosphere, and then subjected to magnetic separation to obtain iron concentrate with high purity and yield, and the recovery effect is comparable to or even better than that of coal or other reducing agents prepared from coal. In addition, the entire method has the advantages of short process, low cost and good recovery effect.

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

[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 values not listed within the value 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 values not listed within the value 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 value 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 values not listed within the value range are also applicable.

[0018] In the laterite nickel ore metallurgical slag provided by 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 alum stone [(H2O)Al3(SO4)2(OH)6] and sodium alum stone [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 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 value range are also applicable.

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

[0021] In the present application, the laterite nickel ore metallurgical slag is subjected to alkali leaching treatment, which can remove the sulfur impurity elements in the laterite nickel ore metallurgical slag.

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

[0023] Preferably, the temperature of the alkali leaching treatment in step (1) is 60-90℃, for example, it can be 60℃, 70℃, 75℃, 80℃ or 90℃, but is not limited to the listed values, and other values not listed in the value range are also applicable, preferably 70-80℃.

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

[0025] Preferably, the time of the alkali leaching treatment in step (1) is 60-140min, for example, it can be 60min, 80min, 100min, 120min or 140min, but is not limited to the listed values, and other values not listed in the value range are also applicable, preferably 80-120min.

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

[0027] The temperature of the first evaporation crystallization is 75-95℃, for example, it can be 75℃, 80℃, 85℃, 90℃ or 95℃, but is not limited to the listed values, and other values not listed in the value range are also applicable.

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

[0029] In the present application, the acid leaching solution is subjected to evaporation crystallization, which can convert calcium impurity elements into by-product calcium chloride product, further improving the resource utilization rate of laterite nickel ore.

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

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

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

[0033] Preferably, the temperature of the acid leaching treatment of step (1) is 60-90℃, for example, it can be 60℃, 70℃, 75℃, 80℃ or 90℃, but is not limited to the listed values, and other values not listed in the value range are also applicable, preferably 70-80℃.

[0034] Preferably, the rotation speed of the acid leaching treatment of 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, and other values not listed in the value range are also applicable, preferably 250-350 rpm.

[0035] Preferably, the time of the acid leaching treatment of step (1) is 60-140 min, for example, it can be 60 min, 80 min, 100 min, 120 min or 140 min, but is not limited to the listed values, and other values not listed in the value range are also applicable, preferably 80-120 min.

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

[0037] The temperature of the second evaporation crystallization is 30-90℃, for example, it can be 30℃, 40℃, 50℃, 70℃ or 90℃, but is not limited to the listed values, and other values not listed in the value range are also applicable.

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

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

[0040] Preferably, the carbonization treatment comprises a step of crushing the biomass before the carbonization treatment.

[0041] Preferably, the carbonization treatment is carried out in an inert atmosphere.

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

[0043] Preferably, the temperature of the carbonization treatment is 350-700℃, for example, it can be 350℃, 400℃, 450℃, 500℃ or 600℃, but is not limited to the listed values, other values not listed in the range of values are also applicable, preferably 400-600℃.

[0044] Preferably, the temperature of the carbonization treatment is 350-700℃, for example, it can be 350℃, 400℃, 450℃, 500℃ or 600℃, but is not limited to the listed values, other values not listed in the range of values are also applicable, preferably 400-600℃.

[0045] Preferably, the time of the carbonization treatment is 80-160min, for example, it can be 80min, 100min, 110min, 120min or 160min, but is not limited to the listed values, other values not listed in the range of values are also applicable, preferably 100-120min.

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

[0047] The present application uses carbon dioxide as an activating agent, the process flow is relatively simple, the waste gas produced is mainly carbon dioxide and water vapor, the environmental pollution is small, and the specific surface area of the biomass reducing agent product obtained at the end is high, the pore structure is developed, and the application range is wide.

[0048] Preferably, the temperature of the activation treatment is 350-600℃, for example, it can be 350℃, 400℃, 450℃, 550℃ or 600℃, but is not limited to the listed values, other values not listed in the range of values are also applicable, preferably 400-550℃.

[0049] Preferably, the temperature of the activation treatment is 350-600℃, for example, it can be 350℃, 400℃, 450℃, 550℃ or 600℃, but is not limited to the listed values, other values not listed in the range of values are also applicable, preferably 400-550℃.

[0050] Preferably, the time of the activation treatment is 40-70min, for example, it can be 40min, 50min, 55min, 60min or 70min, but is not limited to the listed values, other values not listed in the range of values are also applicable, preferably 50-60min.

[0051] In the present application, by sequentially performing carbonization and activation treatment on biomass, a biomass reducing agent with enhanced reducing property can be obtained, and the biomass raw material is easy to obtain and environmentally friendly.

[0052] Preferably, the activation process further comprises the steps of grinding, sieving, impurity removing and drying the activated biomass.

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

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

[0055] In the present application, the particle size of the biomass reducing agent is controlled in a specific range, the specific surface area is increased, and the activity of the biomass reducing agent is improved.

[0056] Preferably, the impurity removing comprises rinsing 3-5 times using deionized water, for example, it can be 3 times, 4 times or 5 times.

[0057] Preferably, the drying temperature is 110-120℃, for example, it can be 110℃, 112℃, 115℃, 118℃ or 120℃, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0058] Preferably, the drying time is 680-800min, for example, it can be 680min, 700min, 720min, 750min or 800min, but is not limited to the listed values, and other values not listed in the 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 residue, for example, it can be 4wt%, 4.5wt%, 5wt%, 5.5wt% or 6wt%, but is not limited to the listed values, and other values not listed in the range are also applicable.

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

[0061] By adding sodium carbonate and / or sodium hydroxide as an additive during the roasting process, the present application can reduce the melting point, save energy consumption, and at the same time, it is beneficial for the reaction of part of the substances in the slag to generate sulfides, which is convenient for removal through subsequent magnetic separation process, and finally further improves the purity of the iron concentrate.

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

[0063] Preferably, the time for the first ball milling treatment in step (2) is 30-120min, for example, it can be 30min, 50min, 80min, 100min or 120min, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0064] In the present application, after the first ball milling treatment, on the one hand, the mixed substances are further mixed uniformly, and on the other hand, the particle size of the mixed substances is smaller, which facilitates the reduction roasting reaction to be sufficient.

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

[0066] The rate of heating is 3-6℃ / min, for example, it can be 3℃ / min, 4℃ / min, 5℃ / min or 6℃ / min, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0067] The temperature endpoint of heating is 500-900℃, for example, it can be 500℃, 600℃, 700℃, 800℃ or 900℃, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0068] The roasting time is 30-180min, for example, it can be 30min, 60min, 100min, 150min or 180min, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0069] Preferably, the flow rate of the inert atmosphere is 1-5mL / min, for example, it can be 1mL / min, 2mL / min, 3mL / min, 4mL / min or 5mL / min, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0070] By controlling the amount of biomass reducing agent in a specific range and controlling the flow rate of the inert atmosphere, the acid leaching residue can be better reduced, and the iron concentrate with high purity and yield can be obtained.

[0071] Preferably, the inert atmosphere comprises argon.

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

[0073] Preferably, the dispersant is added in an amount of 3-5wt% of the mass of the calcination product, for example, it can be 3wt%, 3.5wt%, 4wt%, 4.5wt% or 5wt%, but is not limited to the listed values, and other values not listed in the value 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 application, the use of dispersants facilitates ball milling, resulting in a mixture with smaller particle size, and also facilitates subsequent magnetic separation.

[0077] Preferably, the secondary ball milling in step (2) is performed for 20-40min, for example, it can be 20min, 25min, 30min, 35min or 40min, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0078] Preferably, before the magnetic separation in step (2), the secondary ball milling product is further subjected to a slurry conditioning treatment with water to obtain an intermediate slurry.

[0079] Preferably, the amount of water added in the slurry conditioning treatment is 4-6 times the mass of the secondary ball milling product, 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 in the value range are also applicable.

[0080] Preferably, the magnetic separation in step (2) is performed at a magnetic field strength of 1000-3000Gs, for example, it can be 1000Gs, 1500Gs, 2000Gs, 2500Gs or 3000Gs, but is not limited to the listed values, and other values not listed in the value range are also applicable, preferably 1500-2500Gs.

[0081] In the present application, the magnetic separation is performed at a specific magnetic field strength, which can result in an iron concentrate with higher purity.

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

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

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

[0085] The obtained alkali leaching residue is subjected to acid leaching treatment, the concentration of the acid solution used is 1-2 mol / L, the solid-liquid ratio is 1g:(4-10)mL, the temperature is 60-90 DEG C, the rotating speed is 200-400 rpm, and the time is 60-140 min, to obtain acid leaching solution and acid leaching residue; the obtained acid leaching solution is subjected to second evaporation crystallization at 30-90 DEG C for 160-200 min, to obtain 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 primary ball milling treatment for 30-120 min, the obtained primary ball milling product is heated to 500-900 DEG C at a rate of 3-6 DEG C / min under an inert atmosphere with a flow rate of 1-5 mL / min, and is calcined for 30-180 min, to obtain a calcined product; the obtained calcined product is mixed with a dispersing agent and subjected to secondary ball milling treatment for 20-40 min, and the obtained secondary ball milling product is subjected to slurry treatment by adding water, and the amount of water added is 4-6 times the mass of the secondary ball milling product; the obtained intermediate slurry is subjected to magnetic separation under a magnetic field strength of 1000-3000 Gs, to obtain iron concentrate;

[0087] The amount of the additive added is 4-6wt% of the mass of the acid leaching residue; the amount of the biomass reducing agent added is 2-5wt% of the mass of the acid leaching residue; and the amount of the dispersing agent added is 3-5wt% of the mass of the calcined product;

[0088] The biomass reducing agent is obtained by sequentially performing carbonization treatment, activation treatment, grinding, passing through a 40-300 mesh sieve, impurity removal, and drying on the biomass after being crushed; the carbonization treatment is performed under an inert atmosphere, the heating rate of the carbonization treatment is 1-5 DEG C / min, the temperature is 350-600 DEG C, and the time is 80-160 min; and the activation treatment is performed under a carbon dioxide atmosphere, the heating rate of the activation treatment is 1-5 DEG C / min, the temperature is 350-600 DEG C, and the time is 40-70 min.

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

[0090] The method for recycling and utilizing laterite nickel ore metallurgical slag provided by the application can remove impurities in the laterite nickel ore metallurgical slag after sequentially performing alkali leaching treatment and acid leaching treatment on the laterite nickel ore metallurgical slag, and further obtains a biomass reducing agent with enhanced reducibility after performing carbonization and activation treatment on the biomass, which is beneficial to further improving the iron recovery effect, and the cost of the biomass reducing agent is relatively low, and the utilization rate of the biomass is improved at the same time; the biomass reducing agent and the acid leaching residue are mixed in a specific proportion, and then reduction roasting is performed under the addition of an additive and a specific atmosphere, and then magnetic separation is performed, so that iron concentrate with high purity and yield is obtained; in addition, the whole method has the advantages of short process, low cost and good recovery effect, and can simultaneously recover byproduct sodium sulfate products and calcium chloride products, greatly improves the resource utilization rate of the laterite nickel ore metallurgical slag, solves the environmental problems caused by long-term stacking and landfill of the laterite nickel ore metallurgical slag, and is beneficial to large-scale popularization and application. DETAILED DESCRIPTION

[0091] The technical solutions of the application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the application, and should not be regarded as specific limitations on the application.

[0092] The experimental methods not specified in the embodiments are usually performed according to the conventional conditions and the conditions described in the manual, or according to the conditions suggested by the manufacturers, and the general equipment, materials, reagents, etc. used are commercially available, unless otherwise specified.

[0093] The application provides a method for recycling and utilizing laterite nickel ore metallurgical slag, which comprises the following steps:

[0094] (1) performing alkali leaching treatment on the laterite nickel ore metallurgical slag to obtain alkali leaching liquid and alkali leaching residue; the obtained alkali leaching liquid is subjected to first evaporation crystallization to obtain sodium sulfate products; the obtained alkali leaching residue is subjected to acid leaching treatment to obtain acid leaching liquid and acid leaching residue; the obtained acid leaching liquid is subjected to second evaporation crystallization to obtain calcium chloride products;

[0095] (2) mixing the biomass reducing agent, the additive and the acid leaching residue obtained in step (1) to perform primary ball milling treatment, and the obtained primary ball milling product is subjected to reduction roasting treatment to obtain a roasting product; the obtained roasting product is mixed with a dispersing agent to perform secondary ball milling treatment, and the obtained secondary ball milling product is subjected to magnetic separation to obtain iron 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 sequentially performing carbonization treatment and activation treatment on biomass.

[0096] The metallurgical slag of laterite nickel ore provided by the application has the following components: 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 alum stone [(H2O)Al3(SO4)2(OH)6] and sodium alum stone [NaAl3(SO4)2(OH)6]; and the water content of the metallurgical slag of laterite nickel ore is 27-28%. The specific components are shown in Table 1.

[0097] Table 1

[0098]

[0099] Example 1

[0100] The embodiment provides a method for recycling and utilizing a metallurgical slag of laterite nickel ore, and the method comprises the following steps:

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

[0102] The obtained alkali 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, the solid-liquid ratio is 1 g:6 mL, the temperature is 75 DEG C, the rotating speed is 300 rpm, and the time is 100 min, so as to obtain an acid leaching solution and an acid leaching residue; the obtained acid leaching solution is subjected to second evaporation crystallization at 50 DEG C for 180 min, so as to obtain a calcium chloride product;

[0103] (2) The coconut shell is crushed to below 3 cm, then is washed with deionized water to remove surface impurities, is dried at 100 DEG C for 480 min, then is subjected to carbonization treatment, activation treatment, ball mill grinding, screening through a 150-mesh sieve, impurity removal by washing with deionized water for 4 times, and drying at 115 DEG C for 750 min in sequence, so as to obtain a biomass reducing agent; the carbonization treatment is carried out in an argon atmosphere, the temperature rising rate of the carbonization treatment is 3 DEG C / min, the temperature is 450 DEG C, and the time is 110 min; the activation treatment is carried out in a carbon dioxide atmosphere, the temperature rising rate of the activation treatment is 3 DEG C / min, the temperature is 500 DEG C, and the time is 55 min;

[0104] Then, the obtained biomass reducing agent, sodium carbonate, and acid leaching residue obtained in step (1) are mixed and subjected to a first ball milling treatment for 80 min. The amount of sodium carbonate added is 5 wt% of the mass of the acid leaching residue, and the amount of biomass reducing agent added is 3.5 wt% of the mass of the acid leaching residue. The obtained first ball milling product is heated to 700℃ at a rate of 4℃ / min under an argon atmosphere with a flow rate of 3 mL / min and calcined for 100 min to obtain a calcined product. The obtained calcined product is mixed with sodium metaphosphate and subjected to a second ball milling treatment for 30 min. The amount of sodium metaphosphate added is 4 wt% of the mass of the calcined product. Water is added to the obtained second ball milling product for slurry treatment. The amount of water added is 5 times the mass of the obtained second ball milling product. The obtained intermediate slurry is separated by magnetic separation at a magnetic separation intensity of 2000 Gs to obtain iron concentrate and non-magnetic material. The non-magnetic material is used to produce building materials.

[0105] Example 2

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

[0107] (1) Alkali leaching treatment was carried out on the metallurgical slag of laterite nickel ore. The alkaline solution used was a sodium hydroxide solution with a concentration of 1 mol / L. The solid-liquid ratio was 1 g: 4 mL, the temperature was 70℃, the rotation speed was 250 rpm, and the time was 120 min to obtain alkaline leaching solution and alkaline leaching residue. The obtained alkaline leaching solution was subjected to a first evaporation crystallization at 75℃ for 200 min to obtain sodium sulfate product.

[0108] The obtained alkaline leaching residue was subjected to acid leaching treatment. The acid used was a 1 mol / L hydrochloric acid solution with 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, resulting in an acid leaching solution and an acid leaching residue. The obtained acid leaching solution was subjected to a second evaporation crystallization at 30 °C for 200 min to obtain calcium chloride product.

[0109] (2) The coconut shell is crushed to less than 3cm, then rinsed with deionized water to remove surface impurities, dried at 100℃ for 480min, and then subjected to carbonization, activation, ball milling, passing through a 40-mesh sieve, rinsing with deionized water three times to remove impurities, and drying at 110℃ for 800min to obtain a biomass reducing agent. The carbonization is carried out in a nitrogen atmosphere, with a heating rate of 2℃ / min, a temperature of 400℃, and a time of 120min. The activation is carried out in a carbon dioxide atmosphere, with a heating rate of 2℃ / min, a temperature of 400℃, and a time of 60min.

[0110] Then the obtained biomass reducing agent, sodium carbonate and the acid leaching residue obtained in step (1) are mixed and subjected to primary ball milling treatment for 30 min, the sodium carbonate is added in an amount of 4 wt% of the mass of the acid leaching residue, and the biomass reducing agent is added in an amount of 3 wt% of the mass of the acid leaching residue; the obtained primary ball milling product is calcined at a temperature of 500℃ at a rate of 3℃ / min under an argon atmosphere with a flow rate of 1 mL / min for 180 min to obtain a calcined product; the obtained calcined product is mixed with sodium hexametaphosphate and subjected to secondary ball milling treatment for 20 min, the sodium hexametaphosphate is added in an amount of 3 wt% of the mass of the calcined product; the obtained secondary ball milling product is subjected to slurry treatment by adding water in an amount of 4 times of the mass of the obtained secondary ball milling product; the obtained intermediate slurry is subjected to magnetic separation under a magnetic field strength of 1500 Gs to obtain iron concentrate and non-magnetic substances, and the non-magnetic substances are used to produce building materials.

[0111] Example 3

[0112] The present embodiment provides a method for recycling laterite nickel ore metallurgical slag resources, which comprises the following steps:

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

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

[0115] (2) The fruit tree branches are crushed to below 3 cm, then washed with deionized water to remove surface impurities, dried at 100℃ for 480 min, then subjected to carbonization treatment, activation treatment, ball mill grinding, passing through a 300 mesh sieve, washing with deionized water for 5 times to remove impurities, and drying at 120℃ for 680 min in sequence to obtain a biomass reducing agent; the carbonization treatment is carried out under an argon atmosphere, the temperature rising rate of the carbonization treatment is 4℃ / min, the temperature is 500℃, and the time is 100 min; the activation treatment is carried out under a carbon dioxide atmosphere, the temperature rising rate of the activation treatment is 4℃ / min, the temperature is 550℃, and the time is 50 min;

[0116] Then the obtained biomass reducing agent, sodium hydroxide and the acid leaching residue obtained in step (1) are mixed and subjected to primary ball milling treatment for 120 min, the adding amount of the sodium hydroxide is 6 wt% of the mass of the acid leaching residue, and the adding amount of the biomass reducing agent is 4 wt% of the mass of the acid leaching residue; the obtained primary ball milling product is calcined at 900℃ at a rate of 6℃ / min under an argon atmosphere with a flow rate of 5 mL / min for 30 min to obtain a calcined product; the obtained calcined product is mixed with water glass and subjected to secondary ball milling treatment for 40 min, the adding amount of the water glass is 5 wt% of the mass of the calcined product; the obtained secondary ball milling product is subjected to slurry treatment by adding water, and the adding amount of water is 6 times of the mass of the obtained secondary ball milling product; the obtained intermediate slurry is subjected to magnetic separation under a magnetic field strength of 2500 Gs to obtain iron concentrate and non-magnetic substances, and the non-magnetic substances are used to produce building materials.

[0117] Example 4

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

[0119] (1) The laterite nickel ore metallurgical slag is subjected to alkali leaching treatment, the used alkali solution is a sodium carbonate solution with a concentration of 1 mol / L, the solid-liquid ratio is 1 g:4 mL, the temperature is 60℃, the rotating speed is 200 rpm, and the time is 140 min, so as to obtain alkali leaching liquid and alkali leaching residue; the obtained alkali leaching liquid is subjected to first evaporation crystallization at 75℃ for 200 min, so as to obtain a sodium sulfate product;

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

[0121] (2) The wheat straw is crushed to below 3 cm, then is washed with deionized water to remove surface impurities, is dried at 100℃ for 480 min, and then is subjected to carbonization treatment, activation treatment, ball mill grinding, 40-mesh screening, deionized water washing three times to remove impurities and 110℃ drying for 800 min in sequence to obtain a biomass reducing agent; the carbonization treatment is carried out under a nitrogen atmosphere, the temperature rising rate of the carbonization treatment is 1℃ / min, the temperature is 350℃, and the time is 160 min; the activation treatment is carried out under a carbon dioxide atmosphere, the temperature rising rate of the activation treatment is 1℃ / min, the temperature is 350℃, and the time is 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 primary ball milling treatment for 30 min, the adding amount of the sodium carbonate is 4 wt% of the mass of the acid leaching residue, and the adding amount of the biomass reducing agent is 2 wt% of the mass of the acid leaching residue; the obtained primary ball milling product is calcined at a temperature of 500℃ at a rate of 3℃ / min under an argon atmosphere with a flow rate of 1 mL / min for 180 min to obtain a calcined product; the obtained calcined product is mixed with caustic starch and subjected to secondary ball milling treatment for 20 min, the adding amount of the caustic starch is 3 wt% of the mass of the calcined product; the obtained secondary ball milling product is subjected to slurry treatment by adding water, and the adding amount of water is 4 times of the mass of the obtained secondary ball milling product; the obtained intermediate slurry is subjected to magnetic separation under a magnetic field strength of 1000 Gs to obtain iron concentrate and non-magnetic substances, and the non-magnetic substances are used to produce building materials.

[0123] Example 5

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

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

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

[0127] (2) The bamboo is crushed to below 3 cm, then washed with deionized water to remove surface impurities, dried at 100℃ for 480 min, then subjected to carbonization treatment, activation treatment, ball mill grinding, 300 mesh screening, deionized water washing for 5 times to remove impurities and drying at 120℃ for 680 min in sequence to obtain a biomass reducing agent; the carbonization treatment is carried out under an argon atmosphere, the temperature rising rate of the carbonization treatment is 5℃ / min, the temperature is 600℃, and the time is 80 min; the activation treatment is carried out under a carbon dioxide atmosphere, the temperature rising rate of the activation treatment is 5℃ / min, the temperature is 600℃, and the time is 40 min;

[0128] Then the obtained biomass reducing agent, sodium hydroxide and the acid leaching residue obtained in step (1) are mixed and subjected to primary ball milling treatment for 120 min, the sodium hydroxide is added in an amount of 6 wt% of the mass of the acid leaching residue, and the biomass reducing agent is added in an amount of 5 wt% of the mass of the acid leaching residue; the obtained primary ball milling product is calcined at a temperature of 900 ℃ at a rate of 6 ℃ / min under an argon atmosphere with a flow rate of 5 mL / min for 30 min to obtain a calcined product; the obtained calcined product is mixed with salted water glass and subjected to secondary ball milling treatment for 40 min, the salted water glass is added in an amount of 5 wt% of the mass of the calcined product; the obtained secondary ball milling product is subjected to slurry treatment by adding water in an amount of 6 times the mass of the secondary ball milling product; the obtained intermediate slurry is subjected to magnetic separation under a magnetic field strength of 3000 Gs to obtain iron concentrate and non-magnetic substances, and the non-magnetic substances are used to produce building materials.

[0129] Example 6

[0130] The embodiment provides a method for recycling and utilizing laterite nickel ore metallurgical slag resources, which is different from example 1 in that, in addition to adjusting the temperature of the alkali leaching treatment in step (1) to 50 ℃, the rest is the same as in example 1.

[0131] Example 7

[0132] The embodiment provides a method for recycling and utilizing laterite nickel ore metallurgical slag resources, which is different from example 1 in that, in addition to adjusting the temperature of the alkali leaching treatment in step (1) to 100 ℃, the rest is the same as in example 1.

[0133] Example 8

[0134] The embodiment provides a method for recycling and utilizing laterite nickel ore metallurgical slag resources, which is different from example 1 in that, in addition to adjusting the rotating speed of the acid leaching treatment in step (1) to 150 rpm, the rest is the same as in example 1.

[0135] Example 9

[0136] The embodiment provides a method for recycling and utilizing laterite nickel ore metallurgical slag resources, which is different from example 1 in that, in addition to adjusting the rotating speed of the acid leaching treatment in step (1) to 450 rpm, the rest is the same as in example 1.

[0137] Example 10

[0138] The embodiment provides a method for recycling and utilizing laterite nickel ore metallurgical slag resources, which is different from example 1 in that, after the activation treatment in step (2), there is no step of grinding by a ball mill and passing through a 150-mesh screen, and the rest is the same as in example 1.

[0139] Example 11

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

[0141] Embodiment 12

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

[0143] Embodiment 13

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

[0145] Embodiment 14

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

[0147] Comparative Example 1

[0148] The comparative example provides a method for recycling and utilizing laterite nickel ore metallurgical slag resources, which is different from the embodiment 1 in that, no step (1) is performed, the acid leaching slag in step (2) is replaced by laterite nickel ore metallurgical slag, and the rest is the same as the embodiment 1.

[0149] Comparative Example 2

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

[0151] Comparative Example 3

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

[0153] Comparative Example 4

[0154] The comparative example provides a method for recycling laterite nickel ore metallurgical slag resources, which is different from example 1 in that step (1) is not subjected to alkaline leaching treatment, 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 target material after magnetic separation / initial mass of laterite nickel ore metallurgical slag) * 100%; purity: (mass of target material after magnetic separation / mass of material after magnetic separation) * 100%, and 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 Example 11 70.72 60.22 Example 12 63.27 64.60 Example 13 60.54 62.96 Example 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 product obtained in examples 4 and 5 is slightly lower than that of examples 1-3, indicating that the parameters are within the preferred range, which is beneficial to obtain iron concentrate with higher purity; from examples 6-9 and example 1, it can be seen that the temperature and speed of alkaline leaching and acid leaching need to be controlled within a reasonable range, and exceeding the limited range will reduce the purity or yield of the iron concentrate product; from example 10 and example 1, it can be seen that the particle size of the biomass reducing agent is too large after the biomass activation treatment without grinding and sieving, which reduces the activity of the biomass reducing agent, thereby reducing the yield of the iron concentrate product; from examples 11 and 12 and example 1, it can be seen that the amount of biomass reducing agent is too low, which significantly reduces the purity of the iron concentrate product, and the amount is too high, which increases the cost of raw materials, and the purity and yield of the iron concentrate product are no longer significantly increased; from examples 13 and 14 and example 1, it can be seen that the magnetic separation strength is too high, which significantly reduces the purity of the iron concentrate product, and the magnetic separation strength is too low, which significantly reduces the yield of the iron concentrate product.

[0159] From comparative examples 1-4 and example 1, it can be seen that the laterite nickel ore metallurgical slag is not subjected to alkaline leaching and acid leaching treatment, or is subjected to acid leaching treatment first and then alkaline leaching treatment, or is subjected to single acid leaching treatment or alkaline leaching treatment, and the purity of the iron concentrate product is significantly reduced.

[0160] In summary, the method for recycling and utilizing laterite nickel ore metallurgical slag provided by the present application can remove impurities in the laterite nickel ore metallurgical slag after sequentially performing alkali leaching treatment and acid leaching treatment on the laterite nickel ore metallurgical slag, and further perform carbonization and activation treatment on the biomass to obtain biomass reducing agent with enhanced reducibility, which is conducive to further improving the iron recovery effect, and the cost of the biomass reducing agent is relatively low, and the utilization rate of the biomass is improved; the biomass reducing agent and the acid leaching residue are mixed in a specific ratio, and then reduction roasting is performed in the presence of an additive and a specific atmosphere, and then magnetic separation is performed, to obtain iron concentrate with high purity and high yield; in addition, the entire method has the advantages of short process, low cost, good recovery effect, etc., and can simultaneously recover by-product sodium sulfate product and calcium chloride product, greatly improving the resource utilization rate of the laterite nickel ore metallurgical slag, solving the environmental problems caused by long-term stacking and landfill of the laterite nickel ore metallurgical slag, and being conducive to large-scale popularization and application.

[0161] The applicant declares that the above description is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and those skilled in the art should understand that any changes or replacements within the technical scope disclosed by the present application can be easily thought of by any person skilled in the art, and all fall within the protection scope and disclosure scope of the present application.

Claims

1. A method for recycling and utilizing laterite nickel ore metallurgical slag resources, characterized in that, The method includes the following steps: (1) Alkali leaching is performed on the laterite nickel ore metallurgical slag to obtain alkali leaching solution and alkali leaching residue; the obtained alkali leaching solution is subjected to first evaporation crystallization to obtain sodium sulfate product; the obtained alkali leaching residue is subjected to acid leaching to obtain acid leaching solution and acid leaching residue; the obtained acid leaching solution is subjected to second evaporation crystallization to obtain calcium chloride product; the temperature of the alkali leaching treatment in step (1) is 70-80℃; the rotation speed of the acid leaching treatment in step (1) is 200-400rpm; by mass percentage, the laterite nickel ore metallurgical slag in step (1) includes the following components: iron 40-45%, sulfur 5-9%, calcium 1.5-6%, aluminum 2.5-6%; the solid-liquid ratio of the alkali leaching treatment is 1g:(5-6)mL; the solid-liquid ratio of the acid leaching treatment is 1g:(5-6)mL; the temperature of the second evaporation crystallization is 40-50℃; (2) The biomass reducing agent, additives and acid leaching residue obtained in step (1) are mixed and subjected to ball milling. The ball milling product is subjected to reduction roasting to obtain roasted product. The roasted product is mixed with dispersant and subjected to ball milling. The ball milling product is subjected to magnetic separation to obtain iron concentrate. The amount of biomass reducing agent added in step (2) is 3.5-4 wt% of the mass of acid leaching residue and does not exceed 4 wt%. The amount of additive added in step (2) is 4.5-5.5 wt% of the mass of acid leaching residue. The additives include sodium carbonate and / or sodium hydroxide. The dispersant includes at least one of sodium metaphosphate, water glass, caustic starch or saline water glass. The saline water glass refers to a mixture of water glass and aluminum sulfate. The biomass reducing agent mentioned in step (2) is obtained by sequentially carbonizing and activating biomass.

2. The method according to claim 1, characterized in that, The concentration of the alkali solution used in step (1) is 1-2 mol / L.

3. The method according to claim 2, characterized in that, The alkaline solution includes sodium hydroxide solution and / or sodium carbonate solution.

4. The method according to claim 1, characterized in that, The rotation speed of the alkaline leaching treatment in step (1) is 200-400 rpm.

5. The method according to claim 4, characterized in that, The rotation speed of the alkaline leaching treatment in step (1) is 250-350 rpm.

6. The method according to claim 1, characterized in that, The alkali leaching treatment in step (1) takes 60-140 minutes.

7. The method according to claim 6, characterized in that, The alkali leaching treatment in step (1) takes 80-120 minutes.

8. The method according to claim 1, characterized in that, Step (1) The temperature of the first evaporation crystallization is 75-95℃ and the time is 160-200min.

9. The method according to claim 1, characterized in that, The concentration of the acid solution used in step (1) is 1-2 mol / L.

10. The method according to claim 1, characterized in that, The acid solution used in step (1) of the acid leaching treatment includes hydrochloric acid solution.

11. The method according to claim 1, characterized in that, The acid leaching temperature in step (1) is 60-90℃.

12. The method according to claim 11, characterized in that, The acid leaching temperature in step (1) is 70-80℃.

13. The method according to claim 1, characterized in that, The rotation speed of the acid leaching treatment in step (1) is 250-350 rpm.

14. The method according to claim 1, characterized in that, The acid leaching time in step (1) is 60-140 min.

15. The method according to claim 14, characterized in that, The acid leaching time in step (1) is 80-120 min.

16. The method according to claim 1, characterized in that, Step (1) The second evaporation and crystallization time is 160-200 min.

17. The method according to claim 1, characterized in that, The biomass includes at least one of coconut shells, wheat straw, corn stalks, bamboo, rice straw, peanut shells, or fruit tree branches.

18. The method according to claim 17, characterized in that, The biomass is coconut husk and / or fruit tree branches.

19. The method according to claim 1, characterized in that, The carbonization process includes a step of pulverizing the biomass.

20. The method according to claim 1, characterized in that, The carbonization process is carried out under an inert atmosphere.

21. The method according to claim 20, characterized in that, The inert atmosphere includes nitrogen and / or argon.

22. The method according to claim 1, characterized in that, The heating rate of the carbonization process is 1-5℃ / min.

23. The method according to claim 22, characterized in that, The heating rate of the carbonization process is 2-4℃ / min.

24. The method according to claim 1, characterized in that, The carbonization process is carried out at a temperature of 350-600℃.

25. The method according to claim 24, characterized in that, The carbonization process is carried out at a temperature of 400-500℃.

26. The method according to claim 1, characterized in that, The carbonization process takes 80-160 minutes.

27. The method according to claim 26, characterized in that, The carbonization process takes 100-120 minutes.

28. The method according to claim 1, characterized in that, The activation process was carried out under a carbon dioxide atmosphere.

29. The method according to claim 1, characterized in that, The heating rate for the activation treatment is 1-5℃ / min.

30. The method according to claim 29, characterized in that, The heating rate for the activation treatment is 2-4℃ / min.

31. The method according to claim 1, characterized in that, The activation treatment temperature is 350-600℃.

32. The method according to claim 31, characterized in that, The activation treatment temperature is 400-550℃.

33. The method according to claim 1, characterized in that, The activation treatment time is 40-70 minutes.

34. The method according to claim 33, characterized in that, The activation treatment time is 50-60 minutes.

35. The method according to claim 1, characterized in that, The activation process also includes grinding, sieving, removing impurities, and drying the activated biomass.

36. The method according to claim 35, characterized in that, The sieve mesh size is 40-300 mesh.

37. The method according to claim 1, characterized in that, The time for one ball milling process in step (2) is 30-120 min.

38. The method according to claim 1, characterized in that, The reduction roasting process described in step (2) specifically includes: heating to 500-900℃ at a rate of 3-6℃ / min under an inert atmosphere and roasting for 30-180min.

39. The method according to claim 38, characterized in that, The flow rate of the inert atmosphere is 1-5 mL / min.

40. The method according to claim 38, characterized in that, The inert atmosphere includes argon.

41. The method according to claim 1, characterized in that, The amount of dispersant added in step (2) is 3-5 wt% of the mass of the calcined product.

42. The method according to claim 1, characterized in that, The secondary ball milling process in step (2) takes 20-40 minutes.

43. The method according to claim 1, characterized in that, Before the magnetic separation in step (2), the process also includes adding water to the obtained secondary ball milling product to prepare an intermediate slurry.

44. The method according to claim 43, characterized in that, The amount of water added in the slurry preparation process is 4-6 times the mass of the resulting secondary ball milling product.

45. The method according to claim 1, characterized in that, The magnetic separation intensity in step (2) is 1000-3000 Gs.

46. ​​The method according to claim 45, characterized in that, The magnetic separation intensity in step (2) is 1500-2500 Gs.

47. The method according to claim 1, characterized in that, The method includes the following steps: (1) Alkali leaching treatment is performed on lateritic nickel ore metallurgical slag. The concentration of the alkali solution used is 1-2 mol / L, the solid-liquid ratio is 1 g:(5-6) mL, the temperature is 70-80℃, the rotation speed is 200-400 rpm, and the time is 60-140 min to obtain alkali leaching solution and alkali leaching slag. The obtained alkali leaching solution is subjected to first evaporation crystallization at 75-95℃ for 160-200 min to obtain sodium sulfate product. The lateritic nickel ore metallurgical slag includes the following components by mass percentage: iron 40-45%, sulfur 5-9%, calcium 1.5-6%, and aluminum 2.5-6%. The obtained alkaline leaching residue is subjected to acid leaching treatment. The concentration of the acid solution is 1-2 mol / L, the solid-liquid ratio is 1 g:(5-6) mL, the temperature is 60-90℃, the rotation speed is 200-400 rpm, and the time is 60-140 min, to obtain acid leaching solution and acid leaching residue. The obtained acid leaching solution is subjected to a second evaporation crystallization at 40-50℃ for 160-200 min to obtain calcium chloride product. (2) After mixing the biomass reducing agent, additives and acid leaching residue obtained in step (1), the mixture is ball-milled for 30-120 min. The ball-milled product is heated to 500-900℃ at a rate of 3-6℃ / min under an inert atmosphere with a flow rate of 1-5 mL / min and roasted for 30-180 min to obtain the roasted product. The roasted product is mixed with the dispersant and ball-milled for 20-40 min. Water is added to the ball-milled product to adjust the slurry. The amount of water added is 4-6 times the mass of the ball-milled product. The intermediate slurry is separated by magnetic separation at a magnetic separation intensity of 1000-3000 Gs to obtain iron concentrate. The additives include sodium carbonate and / or sodium hydroxide; the dispersant includes at least one of sodium metaphosphate, water glass, caustic starch, or salinized water glass; the salinized water glass refers to a mixture of water glass and aluminum sulfate; The additive is added at 4.5-5.5 wt% of the weight of the acid leaching residue; the biomass reducing agent is added at 3.5-4 wt% of the weight of the acid leaching residue, excluding 4 wt%; the dispersant is added at 3-5 wt% of the weight of the roasted product. The biomass reducing agent is obtained by crushing biomass and then sequentially carbonizing, activating, grinding, passing through a 40-300 mesh sieve, removing impurities, and drying. The carbonization is carried out under an inert atmosphere, with a heating rate of 1-5℃ / min, a temperature of 350-600℃, and a time of 80-160min. The activation is carried out under a carbon dioxide atmosphere, with a heating rate of 1-5℃ / min, a temperature of 350-600℃, and a time of 40-70min.

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