Iron resource recovery method for laterite-nickel ore leaching residues

Abstract

The invention relates to an iron resource recovery method for laterite-nickel ore leaching residues, which comprises the following steps: sequentially carrying out first acid leaching, alkaline leaching, second acid leaching, ore grinding and magnetic separation on the laterite-nickel ore leaching residues to obtain iron ore concentrate with the total iron grade of 60-65wt%; a first leaching agent in the first acid leaching is hydrochloric acid; a second leaching agent in the second acid leaching is hydrochloric acid. According to the iron resource recycling method, the problems of high energy consumption and pollution caused by reduction roasting can be solved, the obtained iron ore concentrate can reach the selling standard, the magnetic separation tailings can be used for producing building materials, cement and other additional products, and effective recycling of iron resources is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy and relates to a method for recovering valuable metals from leaching residue, in particular to a method for recovering iron resources from laterite nickel ore leaching residue. Background Art

[0002] Nickel is a strategic reserve metal with a wide range of applications and a crucial role. As a primary material for new energy battery production, nickel resources are increasingly in demand with the rapid development of the new energy industry. High-pressure acid leaching (HPAL) is currently the most advanced hydrometallurgical technology for laterite nickel ore, typically used to process low-grade limonite.

[0003] The high-pressure acid leaching process for nickel extraction produces a large amount of acid leaching residue. Existing technology generates 100 to 200 tons of leaching residue for every ton of nickel produced. Furthermore, with the increasing commissioning of laterite nickel ore hydroprocessing projects by various domestic companies, the amount of leaching residue discharged has increased annually, becoming a significant solid waste. Currently, the majority of leaching residue disposal methods involve direct landfill at a cost.

[0004] The iron content in leached residue is typically 30-55% by weight, and the harmful impurity S content is typically 1-7% by weight. Currently, the pyrometallurgical method of reducing roasting and magnetic separation is mostly used to recover the iron resources in this type of leached residue. Reducing roasting reduces the sulfur content in the slag and converts the weakly magnetic Fe2O3 in the slag into the strongly magnetic Fe3O4, facilitating further iron enrichment and improving the total iron grade. However, the temperature required for reducing roasting is typically above 800°C, resulting in significant energy consumption and high process costs. Furthermore, high-pressure acid leaching typically uses sulfuric acid as a leaching agent, which results in a high S content in the leached residue. Roasting alone often fails to reduce the sulfur content to less than 0.5%. Furthermore, most high-pressure acid leaching processes mix the ferroaluminum slag produced during the smelting process with the high-pressure acid leaching residue, which can result in an Al content in the waste residue of 3-5% by weight. Roasting and magnetic separation alone cannot effectively reduce the Al content in the slag and cannot meet the Al impurity content requirements of iron concentrate.

[0005] In order to solve the existing problems of excessive accumulation of laterite nickel ore leaching residue, huge landfill processing volume and high roasting energy consumption, it is necessary to provide a method for recovering iron resources from laterite nickel ore leaching residue. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a method for recovering iron resources from laterite nickel ore leaching residue, which can solve the problems of high energy consumption and pollution caused by reduction roasting. The obtained iron concentrate can meet the sales standards, and the magnetic separation tailings can be used to produce additional products such as building materials and cement, thereby realizing the effective recovery of iron resources.

[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 recovering iron resources from laterite nickel ore leaching residue, the method comprising:

[0009] The laterite nickel ore leaching residue is subjected to first acid leaching, alkaline leaching, second acid leaching, grinding and magnetic separation in sequence to obtain an iron concentrate with a total iron grade of 60wt%-65wt%.

[0010] The first leaching agent in the first acid leaching is hydrochloric acid.

[0011] The second leaching agent in the second acid leaching is hydrochloric acid.

[0012] The iron resource recovery method provided by the present invention solves the high energy consumption and pollution problems caused by reduction roasting by sequentially performing first acid leaching, alkaline leaching, second acid leaching, grinding and magnetic separation. The obtained iron concentrate can meet the sales standards, and the magnetic separation tailings can be used to produce additional products such as building materials and cement, thereby realizing the effective recovery of iron resources.

[0013] The first acid leaching in the iron resource recovery method provided by the invention is used to preliminarily remove Al, S and Ca from the laterite nickel ore leaching residue. The first leaching agent used in this process is hydrochloric acid, which not only reduces costs but also reacts with aluminum vanadium and calcium sulfate to facilitate the dissolution of Al and Ca. The subsequent alkaline leaching can remove most of the Al and part of the sulfur. The second acid leaching is then used to remove the remaining S, Al and Ca, reducing the interference of impurities on magnetic separation and alleviating the separation pressure of magnetic separation. Since the Fe in the laterite nickel ore leaching residue exists in the form of uniform spherical crystals, Al 3+ The vanadium is adsorbed on the crystals in the form of aluminum. The present invention separates the aluminum and vanadium from the Fe crystals by grinding, which is convenient for subsequent magnetic separation. The iron resource recovery method provided by the present invention can reduce the amount of alkali solution used in alkaline leaching by acid leaching, thereby reducing costs.

[0014] By the iron resource recovery method provided by the present invention, the total iron grade of the obtained iron concentrate is 60wt%-65wt%, for example, it can be 60wt%, 61wt%, 62wt%, 63wt%, 64wt% or 65wt%, but is not limited to the listed values, and the other unlisted values within the numerical range are also applicable.

[0015] When the pH value of the first acid leaching is too low, the concentration of hydrochloric acid used is too high, resulting in the dissolution of additional iron oxides during acid leaching, resulting in a low subsequent iron recovery rate; when the pH value of the first acid leaching is too high, the concentration of hydrochloric acid used is too low, resulting in impurities being unable to enter the leachate, affecting the subsequent total iron grade.

[0016] Preferably, the pH value of the first acid leaching is 0.5-3, for example, it can be 0.5, 1, 1.5, 2, 2.5 or 3, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0017] Preferably, the temperature of the first acid leaching is 40°C-90°C, for example, 40°C, 50°C, 60°C, 70°C, 80°C or 90°C, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0018] Preferably, the solid-liquid ratio of the first acid leaching is 1:3-1:5, for example, 1:3, 1:3.5, 1:4, 1:4.5 or 1:5, but is not limited to the listed values. Other values not listed within the numerical range are also applicable. The unit of solid-liquid ratio is g / mL.

[0019] Preferably, the first acid leaching time is 0.5h-12h, for example, 0.5h, 1h, 3h, 5h, 6h, 8h, 10h or 12h, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0020] When the pH value of the second acid leaching is too low, the concentration of hydrochloric acid used is too high, resulting in the dissolution of additional iron oxides during acid leaching, resulting in a low subsequent iron recovery rate; when the pH value of the second acid leaching is too high, the concentration of hydrochloric acid used is too low, resulting in impurities being unable to enter the leachate, affecting the subsequent total iron grade.

[0021] Preferably, the pH value of the second acid leaching is 0.5-3, for example, it can be 0.5, 1, 1.5, 2, 2.5 or 3, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0022] Preferably, the temperature of the second acid leaching is 40°C-90°C, for example, 40°C, 50°C, 60°C, 70°C, 80°C or 90°C, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0023] Preferably, the solid-liquid ratio of the second acid leaching is 1:3-1:5, for example, 1:3, 1:3.5, 1:4, 1:4.5 or 1:5, but is not limited to the listed values. Other values not listed within the numerical range are also applicable. The unit of solid-liquid ratio is g / mL.

[0024] Preferably, the second acid leaching time is 0.5h-12h, for example, 0.5h, 1h, 3h, 5h, 6h, 8h, 10h or 12h, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0025] Preferably, the alkali leaching is carried out using an alkali solution, and the alkaline substance in the alkali solution includes any one or a combination of at least two of sodium hydroxide, sodium carbonate, sodium bicarbonate or ammonia water. Typical but non-limiting combinations include a combination of sodium hydroxide and sodium carbonate, a combination of sodium carbonate and sodium bicarbonate, a combination of sodium carbonate and ammonia water, a combination of sodium bicarbonate and ammonia water, or a combination of sodium carbonate, sodium bicarbonate and ammonia water.

[0026] Optionally, the concentration of the alkali solution is 1 mol / L to 5 mol / L, for example, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L or 5 mol / L, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0027] Preferably, the alkali-ore ratio of the alkali solution is 1:3 or more, and the alkali-ore ratio is the mass ratio of the alkali solution to the acid leaching residue obtained by the first acid leaching.

[0028] Preferably, the alkali leaching temperature is 40°C-90°C, for example, 40°C, 50°C, 60°C, 70°C, 80°C or 90°C, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0029] Preferably, the solid-liquid ratio of the alkali leaching is 1:3-1:5, for example, it can be 1:3, 1:3.5, 1:4, 1:4.5 or 1:5, but is not limited to the listed values. Other values not listed within the numerical range are also applicable. The unit of solid-liquid ratio is g / mL.

[0030] Preferably, the alkali leaching time is 0.5h-12h, for example, it can be 0.5h, 1h, 3h, 5h, 6h, 8h, 10h or 12h, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0031] Preferably, the first acid leaching, the alkali leaching and the second acid leaching are followed by water washing independently.

[0032] Preferably, the number of water washings is at least 3 times, for example, 3 times, 4 times, 5 times or 6 times, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0033] Preferably, the solid-liquid ratio of the water washing is 1:3-1:5, for example, it can be 1:3, 1:3.5, 1:4, 1:4.5 or 1:5, but is not limited to the listed values. Other unlisted values within the numerical range are also applicable. The unit of solid-liquid ratio is g / mL.

[0034] Preferably, the slurry concentration during grinding is 10wt%-30wt%, for example, it can be 10wt%, 15wt%, 20wt%, 25wt% or 30wt%, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0035] Preferably, the end point of the grinding is to make the particle size D90 ≤ 10 μm, for example, it can be 2 μm, 4 μm, 5 μm, 6 μm, 8 μm or 10 μm, but is not limited to the listed values, and other values not listed in the numerical range are also applicable.

[0036] Preferably, the pulp concentration during magnetic separation is 10wt%-80wt%, for example, it can be 10wt%, 30wt%, 50wt%, 60wt% or 80wt%, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0037] Preferably, the dispersant is added at a ratio of 0.4 kg / t-2 kg / t during the magnetic separation, that is, 0.4 kg-2 kg of dispersant is added per ton of slurry, for example, it can be 0.4 kg, 0.5 kg, 0.8 kg, 1 kg, 1.2 kg, 1.5 kg, 1.8 kg or 2 kg, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0038] Preferably, the dispersant includes any one of sodium tripolyphosphate, water glass or sodium hexametaphosphate or a combination of at least two thereof. Typical but non-limiting combinations include a combination of sodium tripolyphosphate and water glass, a combination of water glass and sodium hexametaphosphate, a combination of sodium tripolyphosphate and sodium hexametaphosphate, or a combination of sodium tripolyphosphate, water glass and sodium hexametaphosphate.

[0039] Preferably, the magnetic separation includes a first magnetic separation and a second magnetic separation performed sequentially.

[0040] Preferably, the magnetic field strength of the first magnetic separation is 1.2T-1.6T, for example, it can be 1.2T, 1.3T, 1.4T, 1.5T or 1.6T, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0041] Preferably, the magnetic field strength of the second magnetic separation is 0.4T-0.6T, for example, 0.4T, 0.5T or 0.6T, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0042] Preferably, the second tailings of the second magnetic separation are returned to the first magnetic separation; and the first tailings of the first magnetic separation are used to prepare additional products.

[0043] The additional products include building materials and / or cement.

[0044] As a preferred technical solution of the iron resource recovery method provided by the present invention, the iron resource recovery method comprises:

[0045] (1) performing a first acid leaching on the laterite nickel ore leaching residue using hydrochloric acid to obtain a first acid leaching residue; the pH value of the first acid leaching is 0.5-3, the temperature is 40° C.-90° C., and the time is 0.5 h-12 h; the solid-liquid ratio of the first acid leaching is 1:3-1:5, and the unit of the solid-liquid ratio is g / mL;

[0046] (2) alkali leaching the first acid leaching residue with alkali solution to obtain alkali leaching residue; the alkali leaching temperature is 40°C-90°C, the time is 0.5h-12h; the solid-liquid ratio of the alkali leaching is 1:3-1:5, and the unit of the solid-liquid ratio is g / mL; the alkali-ore ratio of the alkali leaching is 1:3 or more;

[0047] (3) performing a second acid leaching on the alkaline leaching residue using hydrochloric acid to obtain a second acid leaching residue; the pH value of the second acid leaching is 0.5-3, the temperature is 40°C-90°C, and the time is 0.5h-12h; the solid-liquid ratio of the second acid leaching is 1:3-1:5, and the unit of the solid-liquid ratio is g / mL;

[0048] (4) mixing water and the second acid leaching residue to obtain a grinding slurry with a concentration of 10 wt% to 30 wt%, and grinding the ore to a particle size D90 ≤ 10 μm to obtain a grinding material;

[0049] (5) Mixing water and grinding material to obtain a magnetic separation slurry with a concentration of 10wt%-80wt%, adding a dispersant at a ratio of 0.4kg / t-2kg / t to uniformly disperse the solid particles, and then performing the first magnetic separation and the second magnetic separation in sequence; the magnetic field strength of the first magnetic separation is 1.2T-1.6T, and the magnetic field strength of the second magnetic separation is 0.4T-0.6T; the tailings of the second magnetic separation are returned to the first magnetic separation; the tailings of the first magnetic separation are used to prepare additional products.

[0050] The numerical range described in the present invention includes not only the point values listed above, but also any point values between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values included in the range.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] The iron resource recovery method provided by the present invention solves the high energy consumption and pollution problems caused by reduction roasting by sequentially performing first acid leaching, alkaline leaching, second acid leaching, grinding and magnetic separation. The obtained iron concentrate can meet the sales standards, and the magnetic separation tailings can be used to produce additional products such as building materials and cement, thereby realizing the effective recovery of iron resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a process flow chart of the iron resource recovery method provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0054] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0055] In a specific embodiment of the present invention, the laterite nickel ore leaching residue is formed by combining the leaching residue obtained from the high-pressure acid leaching (HPAL) process with the iron-aluminum slag produced during the impurity removal process. In terms of mass percentage, the main components thereof are 40 wt% Fe, 3.15 wt% Al, 7.07 wt% S, 5.16 wt% Ca, 7.13 wt% Si, 11 wt% Cr, 0.3 wt% Na, 0.5 wt% Mg, 0.0013 wt% Co, 0.04 wt% Ni, and 0.11 wt% Mn. The above description is only for the completeness of the technical solution and is not to be considered as a further limitation of the technical solution of the present invention.

[0056] Example 1

[0057] This embodiment provides a Figure 1 The iron resource recovery method of laterite nickel ore leaching residue shown in the figure comprises:

[0058] (1) using hydrochloric acid to perform a first acid leaching on the laterite nickel ore leaching residue to obtain a first acid leaching residue; the pH value of the first acid leaching is 0.5, the temperature is 75°C, and the time is 2 hours; the solid-liquid ratio of the first acid leaching is 1:4, and the unit of the solid-liquid ratio is g / mL; after the first acid leaching is completed, the first acid leaching residue is washed twice with water at a solid-liquid ratio of 1g / 3mL;

[0059] (2) alkali leaching the first acid leaching residue with sodium hydroxide solution to obtain alkali leaching residue; the alkali leaching temperature is 75°C, the time is 2 hours, the solid-liquid ratio of the alkali leaching is 1:3-1:5, and the unit of the solid-liquid ratio is g / mL; after the alkali leaching is completed, the alkali leaching residue is washed twice with water at a solid-liquid ratio of 1g / 3mL; the alkali ore ratio of the alkali leaching is 1:3;

[0060] (3) performing a second acid leaching on the alkaline leaching residue using hydrochloric acid to obtain a second acid leaching residue; the pH value of the second acid leaching is 1.5, the temperature is 75°C, and the time is 2 hours; the solid-liquid ratio of the second acid leaching is 1:4, and the unit of the solid-liquid ratio is g / mL; after the second acid leaching is completed, the second acid leaching residue is washed twice with water at a solid-liquid ratio of 1g / 3mL;

[0061] (4) mixing water and the second acid leaching residue to obtain a grinding slurry with a concentration of 30 wt%; grinding the ore in a sand mill to a particle size D90 of 8 μm to obtain a grinding material;

[0062] (5) Mixing water and grinding material to obtain a magnetic separation slurry with a concentration of 30 wt%, adding sodium hexametaphosphate at a ratio of 0.75 kg / t to uniformly disperse the solid particles, and then performing the first magnetic separation and the second magnetic separation in sequence to obtain iron concentrate; the magnetic field strength of the first magnetic separation is 1.2 T, and the magnetic field strength of the second magnetic separation is 0.4 T; the tailings of the second magnetic separation are returned to the first magnetic separation; the tailings of the first magnetic separation are used to prepare additional products.

[0063] Example 2

[0064] This embodiment provides a method for recovering iron resources from laterite nickel ore leaching residue, the method comprising:

[0065] (1) using hydrochloric acid to perform a first acid leaching on the laterite nickel ore leaching residue to obtain a first acid leaching residue; the pH value of the first acid leaching is 0.5, the temperature is 75°C, and the time is 2 hours; the solid-liquid ratio of the first acid leaching is 1:4, and the unit of the solid-liquid ratio is g / mL; after the first acid leaching is completed, the first acid leaching residue is washed twice with water at a solid-liquid ratio of 1g / 3mL;

[0066] (2) using sodium hydroxide solution to alkali-leach the first acid leaching residue to obtain alkali-leach residue; the alkali leaching temperature is 75 ° C, the time is 2 hours; the solid-liquid ratio of the alkali leaching is 1:3-1:5, and the unit of the solid-liquid ratio is g / mL; after the alkali leaching is completed, the alkali leaching residue is washed twice with water at a solid-liquid ratio of 1g / 3mL; the alkali-ore ratio of the alkali leaching is 1:3

[0067] (3) performing a second acid leaching on the alkaline leaching residue using hydrochloric acid to obtain a second acid leaching residue; the pH value of the second acid leaching is 1.5, the temperature is 75°C, and the time is 2 hours; the solid-liquid ratio of the second acid leaching is 1:4, and the unit of the solid-liquid ratio is g / mL; after the second acid leaching is completed, the second acid leaching residue is washed twice with water at a solid-liquid ratio of 1g / 3mL;

[0068] (4) mixing water and the second acid leaching residue to obtain a grinding slurry with a concentration of 30 wt%; grinding the ore in a sand mill to a particle size D90 of 8 μm to obtain a grinding material;

[0069] (5) Mixing water and grinding material to obtain a magnetic separation slurry with a concentration of 30 wt%, adding sodium hexametaphosphate at a ratio of 0.75 kg / t to uniformly disperse the solid particles, and then performing the first magnetic separation and the second magnetic separation in sequence to obtain iron concentrate; the magnetic field strength of the first magnetic separation is 1.6 T, and the magnetic field strength of the second magnetic separation is 0.6 T; the tailings of the second magnetic separation are returned to the first magnetic separation; the tailings of the first magnetic separation are used to prepare additional products.

[0070] Example 3

[0071] This embodiment provides a method for recovering iron resources from laterite nickel ore leaching residue, the method comprising:

[0072] (1) using hydrochloric acid to perform a first acid leaching on the laterite nickel ore leaching residue to obtain a first acid leaching residue; the pH value of the first acid leaching is 0.5, the temperature is 75°C, and the time is 2 hours; the solid-liquid ratio of the first acid leaching is 1:4, and the unit of the solid-liquid ratio is g / mL; after the first acid leaching is completed, the first acid leaching residue is washed twice with water at a solid-liquid ratio of 1g / 3mL;

[0073] (2) alkali leaching the first acid leaching residue with sodium hydroxide solution to obtain alkali leaching residue; the alkali leaching temperature is 75°C, the time is 2 hours, the solid-liquid ratio of the alkali leaching is 1:3-1:5, and the unit of the solid-liquid ratio is g / mL; after the alkali leaching is completed, the alkali leaching residue is washed twice with water at a solid-liquid ratio of 1g / 3mL; the alkali ore ratio of the alkali leaching is 1:3;

[0074] (3) performing a second acid leaching on the alkaline leaching residue using hydrochloric acid to obtain a second acid leaching residue; the pH value of the second acid leaching is 1.5, the temperature is 75°C, and the time is 2 hours; the solid-liquid ratio of the second acid leaching is 1:4, and the unit of the solid-liquid ratio is g / mL; after the second acid leaching is completed, the second acid leaching residue is washed twice with water at a solid-liquid ratio of 1g / 3mL;

[0075] (4) mixing water and the second acid leaching residue to obtain a grinding slurry with a concentration of 30 wt%; grinding the ore in a sand mill to a particle size D90 of 8 μm to obtain a grinding material;

[0076] (5) Mixing water and grinding material to obtain a magnetic separation slurry with a concentration of 30 wt%, adding sodium hexametaphosphate at a ratio of 0.75 kg / t to uniformly disperse the solid particles, and then performing the first magnetic separation and the second magnetic separation in sequence to obtain iron concentrate; the magnetic field strength of the first magnetic separation is 1.4 T, and the magnetic field strength of the second magnetic separation is 0.5 T; the tailings of the second magnetic separation are returned to the first magnetic separation; the tailings of the first magnetic separation are used to prepare additional products.

[0077] Example 4

[0078] This embodiment provides a method for recovering iron resources from laterite nickel ore leaching residue, the method comprising:

[0079] (1) using hydrochloric acid to perform a first acid leaching on the laterite nickel ore leaching residue to obtain a first acid leaching residue; the pH value of the first acid leaching is 0.5, the temperature is 75°C, and the time is 2 hours; the solid-liquid ratio of the first acid leaching is 1:4, and the unit of the solid-liquid ratio is g / mL; after the first acid leaching is completed, the first acid leaching residue is washed twice with water at a solid-liquid ratio of 1g / 3mL;

[0080] (2) alkali leaching the first acid leaching residue with sodium hydroxide solution to obtain alkali leaching residue; the alkali leaching temperature is 75°C, the time is 2 hours, the solid-liquid ratio of the alkali leaching is 1:3-1:5, and the unit of the solid-liquid ratio is g / mL; after the alkali leaching is completed, the alkali leaching residue is washed twice with water at a solid-liquid ratio of 1g / 3mL; the alkali ore ratio of the alkali leaching is 1:3;

[0081] (3) performing a second acid leaching on the alkaline leaching residue using hydrochloric acid to obtain a second acid leaching residue; the pH value of the second acid leaching is 1.5, the temperature is 75°C, and the time is 2 hours; the solid-liquid ratio of the second acid leaching is 1:4, and the unit of the solid-liquid ratio is g / mL; after the second acid leaching is completed, the second acid leaching residue is washed twice with water at a solid-liquid ratio of 1g / 3mL;

[0082] (4) mixing water and the second acid leaching residue to obtain a grinding slurry with a concentration of 30 wt%; grinding the ore in a sand mill to a particle size D90 of 8 μm to obtain a grinding material;

[0083] (5) Mixing water and grinding material to obtain a magnetic separation slurry with a concentration of 30 wt%, adding sodium hexametaphosphate at a ratio of 0.4 kg / t to uniformly disperse the solid particles, and then performing the first magnetic separation and the second magnetic separation in sequence to obtain iron concentrate; the magnetic field strength of the first magnetic separation is 1.2 T, and the magnetic field strength of the second magnetic separation is 0.4 T; the tailings of the second magnetic separation are returned to the first magnetic separation; the tailings of the first magnetic separation are used to prepare additional products.

[0084] Example 5

[0085] This embodiment provides a method for recovering iron resources from laterite nickel ore leaching residue, the method comprising:

[0086] (1) using hydrochloric acid to perform a first acid leaching on the laterite nickel ore leaching residue to obtain a first acid leaching residue; the pH value of the first acid leaching is 0.5, the temperature is 75°C, and the time is 2 hours; the solid-liquid ratio of the first acid leaching is 1:4, and the unit of the solid-liquid ratio is g / mL; after the first acid leaching is completed, the first acid leaching residue is washed twice with water at a solid-liquid ratio of 1g / 3mL;

[0087] (2) alkali leaching the first acid leaching residue with sodium hydroxide solution to obtain alkali leaching residue; the alkali leaching temperature is 75°C, the time is 2 hours, the solid-liquid ratio of the alkali leaching is 1:3-1:5, and the unit of the solid-liquid ratio is g / mL; after the alkali leaching is completed, the alkali leaching residue is washed twice with water at a solid-liquid ratio of 1g / 3mL; the alkali ore ratio of the alkali leaching is 1:3;

[0088] (3) performing a second acid leaching on the alkaline leaching residue using hydrochloric acid to obtain a second acid leaching residue; the pH value of the second acid leaching is 1.5, the temperature is 75°C, and the time is 2 hours; the solid-liquid ratio of the second acid leaching is 1:4, and the unit of the solid-liquid ratio is g / mL; after the second acid leaching is completed, the second acid leaching residue is washed twice with water at a solid-liquid ratio of 1g / 3mL;

[0089] (4) mixing water and the second acid leaching residue to obtain a grinding slurry with a concentration of 30 wt%; grinding the ore in a sand mill to a particle size D90 of 8 μm to obtain a grinding material;

[0090] (5) Mixing water and grinding material to obtain a magnetic separation slurry with a concentration of 30 wt%, adding sodium hexametaphosphate at a ratio of 2 kg / t to uniformly disperse the solid particles, and then performing the first magnetic separation and the second magnetic separation in sequence to obtain iron concentrate; the magnetic field strength of the first magnetic separation is 1.2 T, and the magnetic field strength of the second magnetic separation is 0.4 T; the tailings of the second magnetic separation are returned to the first magnetic separation; the tailings of the first magnetic separation are used to prepare additional products.

[0091] Example 6

[0092] This embodiment provides a method for recovering iron resources from laterite nickel ore leaching residue, which is the same as that of Example 1 except that no dispersant is added during magnetic separation.

[0093] Example 7

[0094] This embodiment provides a method for recovering iron resources from laterite nickel ore leaching residue, which is the same as that of Example 1 except that the sodium hydroxide solution during alkaline leaching is replaced by a sodium carbonate solution.

[0095] Example 8

[0096] This embodiment provides a method for recovering iron resources from laterite nickel ore leaching residue, the method comprising:

[0097] (1) using hydrochloric acid to perform a first acid leaching on the laterite nickel ore leaching residue to obtain a first acid leaching residue; the pH value of the first acid leaching is 0.5, the temperature is 40°C, and the time is 12 hours; the solid-liquid ratio of the first acid leaching is 1:3, and the unit of the solid-liquid ratio is g / mL; after the first acid leaching is completed, the first acid leaching residue is washed twice with water at a solid-liquid ratio of 1g / 4mL;

[0098] (2) alkali leaching the first acid leaching residue with sodium hydroxide solution to obtain alkali leaching residue; the alkali leaching temperature is 40°C, the time is 12 hours, the solid-liquid ratio of the alkali leaching is 1:3-1:5, and the unit of the solid-liquid ratio is g / mL; after the alkali leaching is completed, the alkali leaching residue is washed twice with water at a solid-liquid ratio of 1g / 4mL;

[0099] (3) performing a second acid leaching on the alkaline leaching residue using hydrochloric acid to obtain a second acid leaching residue; the pH value of the second acid leaching is 0.5, the temperature is 40°C, and the time is 12 hours; the solid-liquid ratio of the second acid leaching is 1:3, and the unit of the solid-liquid ratio is g / mL; after the second acid leaching is completed, the second acid leaching residue is washed twice with water at a solid-liquid ratio of 1g / 4mL;

[0100] (4) mixing water and the second acid leaching residue to obtain a grinding slurry with a concentration of 10 wt %; grinding the ore in a sand mill to a particle size D90 of 8 μm to obtain a grinding material;

[0101] (5) Mixing water and grinding material to obtain a magnetic separation slurry with a concentration of 10 wt%, adding sodium hexametaphosphate at a ratio of 0.75 kg / t to uniformly disperse the solid particles, and then performing the first magnetic separation and the second magnetic separation in sequence to obtain iron concentrate; the magnetic field strength of the first magnetic separation is 1.2 T, and the magnetic field strength of the second magnetic separation is 0.4 T; the tailings of the second magnetic separation are returned to the first magnetic separation; the tailings of the first magnetic separation are used to prepare additional products.

[0102] Example 9

[0103] This embodiment provides a method for recovering iron resources from laterite nickel ore leaching residue, the method comprising:

[0104] (1) using hydrochloric acid to perform a first acid leaching on the laterite nickel ore leaching residue to obtain a first acid leaching residue; the pH value of the first acid leaching is 0.5, the temperature is 90°C, and the time is 0.5h; the solid-liquid ratio of the first acid leaching is 1:5, and the unit of the solid-liquid ratio is g / mL; after the first acid leaching is completed, the first acid leaching residue is washed twice with water at a solid-liquid ratio of 1g / 5mL;

[0105] (2) alkali leaching the first acid leaching residue with a sodium hydroxide solution to obtain an alkali leaching residue; the alkali leaching temperature is 90° C., the time is 0.5 h, the solid-liquid ratio of the alkali leaching is 1:3-1:5, and the unit of the solid-liquid ratio is g / mL; after the alkali leaching is completed, the alkali leaching residue is washed twice with water at a solid-liquid ratio of 1 g / 5 mL;

[0106] (3) performing a second acid leaching on the alkaline leaching residue using hydrochloric acid to obtain a second acid leaching residue; the pH value of the second acid leaching is 3, the temperature is 90°C, and the time is 0.5h; the solid-liquid ratio of the second acid leaching is 1:5, and the unit of the solid-liquid ratio is g / mL; after the second acid leaching is completed, the second acid leaching residue is washed twice with water at a solid-liquid ratio of 1g / 4mL;

[0107] (4) mixing water and the second acid leaching residue to obtain a grinding slurry with a concentration of 30 wt%; grinding the ore in a sand mill to a particle size D90 of 10 μm to obtain a grinding material;

[0108] (5) Mixing water and grinding material to obtain a magnetic separation slurry with a concentration of 80 wt%, adding sodium hexametaphosphate at a ratio of 0.75 kg / t to uniformly disperse the solid particles, and then performing the first magnetic separation and the second magnetic separation in sequence to obtain iron concentrate; the magnetic field strength of the first magnetic separation is 1.2 T, and the magnetic field strength of the second magnetic separation is 0.4 T; the tailings of the second magnetic separation are returned to the first magnetic separation; the tailings of the first magnetic separation are used to prepare additional products.

[0109] Example 10

[0110] This embodiment provides a method for recovering iron resources from laterite nickel ore leaching residue. Except for changing the concentration of hydrochloric acid to make the pH value of the first acid leaching 0.1, the rest is the same as that of Example 1.

[0111] Example 11

[0112] This embodiment provides a method for recovering iron resources from laterite nickel ore leaching residue. Except for changing the concentration of hydrochloric acid to make the pH value of the first acid leaching 3.5, the rest is the same as that of Example 1.

[0113] Example 12

[0114] This embodiment provides a method for recovering iron resources from laterite nickel ore leaching residue. Except for changing the concentration of hydrochloric acid to make the pH value of the second acid leaching 3.5, the rest is the same as that of Example 1.

[0115] Comparative Example 1

[0116] This comparative example provides a method for recovering iron resources from laterite nickel ore leaching residue, which is the same as Example 1 except that sulfuric acid is used as the leaching agent in the first acid leaching.

[0117] Comparative Example 2

[0118] This comparative example provides a method for recovering iron resources from laterite nickel ore leaching residue, which is the same as Example 1 except that sulfuric acid is used as the leaching agent in the second acid leaching.

[0119] In the iron resource recovery methods provided in the above embodiments and comparative examples, the iron recovery rate, total iron grade (TFe) of the iron concentrate, sulfur content, and aluminum content were measured, and the results are shown in Table 1.

[0120] Table 1

[0121]

[0122] In summary, the iron resource recovery method provided by the present invention solves the high energy consumption and pollution problems caused by reduction roasting by sequentially performing the first acid leaching, alkaline leaching, second acid leaching, grinding and magnetic separation. The obtained iron concentrate can meet the sales standards, and the magnetic separation tailings can be used to produce additional products such as building materials and cement, thereby realizing the effective recovery of iron resources.

[0123] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection 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 fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for recovering iron resources from laterite nickel ore leaching residue, characterized in that: The iron resource recovery method comprises: The laterite nickel ore leaching residue is sequentially subjected to a first acid leaching, an alkaline leaching, a second acid leaching, grinding and magnetic separation to obtain an iron concentrate with a total iron grade of 60wt%-65wt%; The first leaching agent in the first acid leaching is hydrochloric acid; The second leaching agent in the second acid leaching is hydrochloric acid.

2. The iron resource recovery method according to claim 1, characterized in that The pH value of the first acid leaching is 0.5-3; Preferably, the temperature of the first acid leaching is 40°C-90°C; Preferably, the solid-liquid ratio of the first acid leaching is 1:3-1:5, and the unit of solid-liquid ratio is g / mL; Preferably, the first acid leaching time is 0.5h-12h.

3. The iron resource recovery method according to claim 1, characterized in that: The pH value of the second acid leaching is 0.5-3; Preferably, the temperature of the second acid leaching is 40°C-90°C; Preferably, the solid-liquid ratio of the second acid leaching is 1:3-1:5, and the unit of solid-liquid ratio is g / mL; Preferably, the second acid leaching time is 0.5h-12h.

4. The iron resource recovery method according to claim 1, characterized in that: The alkaline leaching is carried out using an alkaline solution, wherein the alkaline substance in the alkaline solution includes any one or a combination of at least two of sodium hydroxide, sodium carbonate, sodium bicarbonate or ammonia water; Preferably, the alkali-ore ratio of the alkali leaching is 1:3 or more; Preferably, the temperature of the alkali leaching is 40°C-90°C; Preferably, the solid-liquid ratio of the alkali leaching is 1:3-1:5, and the unit of the solid-liquid ratio is g / mL; Preferably, the alkali leaching time is 0.5h-12h.

5. The iron resource recovery method according to any one of claims 1 to 4, characterized in that: After the first acid leaching, the alkaline leaching and the second acid leaching, water washing is performed independently; Preferably, the number of times of washing is at least 2 times; Preferably, the solid-liquid ratio of the water washing is 1:3-1:5, and the unit of the solid-liquid ratio is g / mL.

6. The iron resource recovery method according to claim 1, characterized in that: The slurry concentration during the grinding is 10wt%-30wt%; Preferably, the end point of the grinding is to make the particle size D90 ≤ 10 μm.

7. The iron resource recovery method according to claim 1, characterized in that: The slurry concentration during magnetic separation is 10wt%-80wt%; Preferably, a dispersant is added during the magnetic separation at a ratio of 0.4 kg / t to 2 kg / t; Preferably, the dispersant includes any one of sodium tripolyphosphate, water glass or sodium hexametaphosphate, or a combination of at least two thereof.

8. The iron resource recovery method according to claim 7, characterized in that: The magnetic separation includes a first magnetic separation and a second magnetic separation performed sequentially; Preferably, the magnetic field strength of the first magnetic separation is 1.2T-1.6T; Preferably, the magnetic field strength of the second magnetic separation is 0.4T-0.6T.

9. The iron resource recovery method according to claim 8, characterized in that: The second tailings from the second magnetic separation are returned to the first magnetic separation; and the first tailings from the first magnetic separation are used to prepare additional products.

10. The iron resource recovery method according to claim 1, characterized in that: The iron resource recovery method comprises: (1) performing a first acid leaching on the laterite nickel ore leaching residue using hydrochloric acid to obtain a first acid leaching residue; the pH value of the first acid leaching is 0.5-3, the temperature is 40° C.-90° C., and the time is 0.5 h-12 h; the solid-liquid ratio of the first acid leaching is 1:3-1:5, and the unit of the solid-liquid ratio is g / mL; (2) alkali leaching the first acid leaching residue with alkali solution to obtain alkali leaching residue; the alkali leaching temperature is 40°C-90°C, the time is 0.5h-12h; the solid-liquid ratio of the alkali leaching is 1:3-1:5, and the unit of the solid-liquid ratio is g / mL; the alkali-ore ratio of the alkali leaching is 1:3 or more; (3) performing a second acid leaching on the alkaline leaching residue using hydrochloric acid to obtain a second acid leaching residue; the pH value of the second acid leaching is 0.5-3, the temperature is 40°C-90°C, and the time is 0.5h-12h; the solid-liquid ratio of the second acid leaching is 1:3-1:5, and the unit of the solid-liquid ratio is g / mL; (4) mixing water and the second acid leaching residue to obtain a grinding slurry with a concentration of 10 wt% to 30 wt%, and grinding the ore to a particle size D90 ≤ 10 μm to obtain a grinding material; (5) Mixing water and grinding material to obtain a magnetic separation slurry with a concentration of 10wt%-80wt%, adding a dispersant at a ratio of 0.4kg / t-2kg / t to uniformly disperse the solid particles, and then performing the first magnetic separation and the second magnetic separation in sequence; the magnetic field strength of the first magnetic separation is 1.2T-1.6T, and the magnetic field strength of the second magnetic separation is 0.4T-0.6T; the tailings of the second magnetic separation are returned to the first magnetic separation; the tailings of the first magnetic separation are used to prepare additional products.

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