A method for the resource utilization of laterite nickel ore

Abstract

The present invention discloses a method for resource utilization of laterite nickel ore, belonging to the technical field of resource utilization of laterite nickel ore. The method includes: subjecting the laterite nickel ore to high-pressure acid leaching, first solid-liquid separation, roasting and water washing the first separation residue in sequence, second solid-liquid separation to obtain a second separation residue and a second separation liquid containing aluminum; subjecting the second separation residue to reduction roasting and magnetic separation to obtain quartz sand and iron concentrate. The method has simple operation, low cost and little environmental pollution, can realize the separation of iron and aluminum in the acid leaching residue of laterite nickel ore and the environmentally friendly recycling of silicon dioxide at the same time, and is beneficial to improving the resource utilization rate of laterite nickel ore.

Description

Technical Field

[0001] The present disclosure relates to the technical field of resource utilization of laterite nickel ore, and in particular to a method for resource utilization of laterite nickel ore. Background Art

[0002] Laterite nickel ore typically contains iron, aluminum, silicon, and may also contain nickel and cobalt. As a source of nickel and cobalt for battery products, laterite nickel ore can be used to prepare positive electrode materials, potentially reducing battery production costs.

[0003] Currently, the development processes for laterite nickel ore are primarily categorized into three types: pyrometallurgical, hydrometallurgical, and a combination of pyrometallurgical and hydrometallurgical methods. The hydrometallurgical process primarily utilizes high-pressure acid leaching, which can separate nickel and cobalt. However, this process also produces a large amount of acid leaching residue. If not properly utilized, this residue not only consumes land resources but also pollutes the environment.

[0004] In view of this, the present disclosure is proposed. Summary of the Invention

[0005] The purpose of the present disclosure includes providing a method for resource utilization of laterite nickel ore, which can solve or improve the above-mentioned technical problems.

[0006] The present disclosure is implemented as follows:

[0007] The present disclosure provides a method for resource utilization of laterite nickel ore, which comprises the following steps:

[0008] High-pressure acid leaching is performed on the laterite nickel ore, and a solid-liquid mixture obtained by the high-pressure acid leaching is subjected to a first solid-liquid separation to obtain a first separated liquid and a first separated slag containing magnetite and alum or grass alum;

[0009] The first separation slag is roasted to decompose alum or alum to produce aluminum hydroxide or aluminum oxide, and the roasted material is then mixed with water for washing, and the washed slurry is subjected to a second solid-liquid separation to obtain a second separation slag containing iron and a second separation liquid containing aluminum;

[0010] The second separated slag is subjected to reduction roasting and magnetic separation to obtain quartz sand and iron concentrate.

[0011] In an optional embodiment, the pressure of the high-pressure acid leaching is 2-2.3 MPa.

[0012] In an alternative embodiment, the temperature of the high pressure acid leaching is 200°C-250°C.

[0013] In an optional embodiment, the high pressure acid leaching time is 2 hours to 4 hours.

[0014] In an alternative embodiment, high-pressure acid treatment involves reacting laterite nickel ore with an acid solution, where the acid solution includes at least one of sulfuric acid solution, hydrochloric acid solution, and nitric acid solution.

[0015] In an alternative embodiment, the mass ratio of laterite nickel ore to the acid solution is 1:2 - 1:4, and the concentration of the acid solution is 140 g / L - 180 g / L.

[0016] In an alternative embodiment, when the laterite nickel ore contains element Z, after the first solid-liquid separation, it further includes: reacting the first separation liquid with an alkali to obtain a hydroxide precipitate of Z;

[0017] where Z is at least one element among cobalt, nickel, and manganese.

[0018] In an alternative embodiment, the roasting temperature is 200°C - 500°C.

[0019] In an alternative embodiment, the roasting time is 1 h - 3 h.

[0020] In an alternative embodiment, the solid-liquid ratio in the water washing process is 1 g:3 mL - 1 g:6 mL.

[0021] In an alternative embodiment, the water washing process is carried out under stirring conditions.

[0022] In an alternative embodiment, the stirring speed is 350 r / min - 400 r / min.

[0023] In an alternative embodiment, after the second solid-liquid separation, it further includes: reacting the second separation liquid with an alkali to obtain aluminum hydroxide.

[0024] In an alternative embodiment, the reduction roasting is to roast the second separation residue with a reducing non-metallic reagent.

[0025] In an alternative embodiment, the temperature of the reduction roasting is 800°C - 1000°C.

[0026] In an alternative embodiment, the time of the reduction roasting is 30 min - 60 min.

[0027] In an alternative embodiment, the mass of the reducing non-metallic reagent is 10% - 20% of the second separation residue.

[0028] In an alternative embodiment, the reducing non-metallic reagent includes at least one of carbon powder, biochar, and reducing organic matter.

[0029] In an alternative embodiment, the biochar includes at least one of wood chips and straw;

[0030] And / or, the reducing organic matter includes at least one of glucose, sucrose, cellulose, fructose, lactose, maltose, ribose, and xylo-oligosaccharide.

[0031] In an alternative embodiment, the exciting current intensity used for magnetic separation is 0.6 A - 1.5 A.

[0032] The beneficial effects of the present disclosure include:

[0033] By roasting the first separation residue obtained after high-pressure acid leaching of laterite nickel ore, the present disclosure can cause the decomposition reaction of jarosite or alum in the first separation residue to generate alumina or aluminum hydroxide. Subsequently, by mixing the roasted material with water for water washing, based on the fact that the mixed slurry of the roasted material and water is weakly acidic, aluminum ions in the mixed slurry exist in the form of aluminum sulfate, and iron ions still exist in the form of precipitation. Then, through the second solid-liquid separation, aluminum is enriched in the second separation liquid, and iron is mainly in the second separation residue, thereby effectively realizing the separation of aluminum and iron. Further, by subjecting the second separation residue to reduction roasting to reduce trivalent iron to magnetic iron, the separation of iron and silicon can be achieved by combining magnetic separation.

[0034] The method provided by the present disclosure has a short treatment process, low operation difficulty, and low treatment cost, can effectively realize the separation of silicon, aluminum, and iron in the acid leaching residue of laterite nickel ore, and fully realizes the resource utilization of the acid leaching residue. Description of the Drawings

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following will briefly introduce the drawings required to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present disclosure, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0036] Figure 1 It is a process flow diagram of the method for resource utilization of laterite nickel ore provided in Embodiment 1 of the present disclosure. Detailed Embodiments

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below. Those not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or instruments not specified by the manufacturer are all conventional products that can be obtained through commercial purchase.

[0038] The following specifically describes the method for resource utilization of laterite nickel ore provided by the present disclosure.

[0039] The present disclosure provides a method for resource utilization of laterite nickel ore, which mainly includes the following steps:

[0040] The laterite nickel ore is subjected to high-pressure acid leaching, and the solid-liquid mixture obtained from the high-pressure acid leaching is subjected to the first solid-liquid separation to obtain a first separation liquid and a first separation residue containing magnetite and alum or alum coquimbite.

[0041] The laterite nickel ore usually contains iron, aluminum, and silicon. In addition, it may also contain element Z, where Z is at least one of cobalt, nickel, and manganese. In the present disclosure, high-pressure acid leaching is to react the laterite nickel ore with an acid solution, and this process can be carried out, for example, in a reaction kettle (such as an autoclave). The first solid-liquid separation can be in the form of filtration, etc. Through high-pressure acid leaching and the first solid-liquid separation, element Z mainly exists in the first separation liquid, and iron, aluminum, and silicon mainly exist in the first separation residue.

[0042] As a reference, the pressure of the high-pressure acid leaching can be 2 - 2.3 MPa, such as 2 MPa, 2.1 MPa, 2.2 MPa, or 2.3 MPa, etc., or any other value within the range of 2 - 2.3 MPa.

[0043] It should be noted that if the pressure of the high-pressure acid leaching is lower than 2 MPa, it is not conducive to iron and aluminum entering the slag, resulting in an increase in impurities in the high-pressure acid leaching solution; if the pressure of the high-pressure acid leaching is higher than 2.3 MPa, it is not conducive to the stable operation of the equipment, and excessive equipment pressure is likely to cause air leakage.

[0044] The temperature of the high-pressure acid leaching can be 200°C - 250°C, such as 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, or 250°C, etc., or any other value within the range of 200°C - 250°C.

[0045] If the temperature of the high-pressure acid leaching is higher than 250°C, it is easy to cause the pressure in the reaction kettle to rise too fast, which requires strict equipment requirements and high equipment costs; if the temperature of the high-pressure acid leaching is lower than 200°C, it will significantly extend the reaction time required.

[0046] Under the above high-pressure acid leaching pressure and temperature conditions, the high-pressure acid leaching time can be 2 h - 4 h, such as 2 h, 2.5 h, 3 h, 3.5 h, or 4 h, etc., or any other value within the range of 2 h - 4 h.

[0047] Continuing from the above, during the above high-pressure acid leaching process, the Fe contained in the laterite nickel ore 3+ mainly undergoes a strong hydrolysis reaction to form magnetite precipitation, and the corresponding reaction equation includes:

[0048] 2α-FeOOH + 6H + →2Fe 3+ + 4H2O;

[0049] 2Fe 3++4H2O → Fe2O3(s) + 6H + ;

[0050] Among them, FeOOH represents iron oxyhydroxide, and "α-" represents a structure of iron oxyhydroxide, which is an orthorhombic and rhombic crystal system structure. (s) represents solid, and the same applies hereinafter.

[0051] Most of the aluminum contained in laterite nickel ore 3+ also undergoes hydrolysis reactions mostly, forming alunogen or alum precipitates and releasing acids. The corresponding reaction equations include:

[0052] 6Al 3+ + 4SO4 2- + 12H2O → 2(H3O)Al3(OH)6(SO4)2(s) + 10H + ;

[0053] 3Al 3+ + 2SO4 2- + M + 6H2O = MAl3(SO4)2(OH)6(s) + 6H + .

[0054] Among them, (H3O)Al3(OH)6(SO4)2 represents alunogen, Al3(SO4)2(OH)6 represents alum, and M includes at least one of Na + , K + and NH4 + , and M also originates from laterite nickel ore.

[0055] As a reference, the mass ratio of laterite nickel ore to the acid solution can be 1:2 - 1:4, such as 1:2, 1:2.5, 1:3, 1:3.5, or 1:4, etc., or any other arbitrary value within the range of 1:2 - 1:4.

[0056] The concentration of the acid solution can be 140 g / L - 180 g / L, such as 140 g / L, 145 g / L, 150 g / L, 155 g / L, 160 g / L, 165 g / L, 170 g / L, 175 g / L, or 180 g / L, etc., or any other arbitrary value within the range of 140 g / L - 180 g / L.

[0057] If the concentration of the acid solution is lower than 140 g / L or the dosage of laterite nickel ore is excessive (such as 1:1), it will lead to more ore and less acid, and the iron, aluminum and other elements in laterite nickel ore cannot be effectively leached out sufficiently; if the concentration of the acid solution is higher than 180 g / L or the dosage of laterite nickel ore is too small (such as 1:5), it will lead to less ore and more acid, resulting in waste of acid.

[0058] Among them, the acid solution can exemplarily but non - restrictively include at least one of sulfuric acid solution, hydrochloric acid solution, and nitric acid solution.

[0059] In some embodiments, when the laterite nickel ore contains element Z, after the first solid-liquid separation, it further includes: reacting the first separation liquid with an alkali to correspondingly obtain a hydroxide precipitate of Z.

[0060] Among them, the alkali can be, for example, NaOH or KOH.

[0061] For reference, when Z contains both nickel and cobalt, nickel and cobalt can be precipitated step by step in the following manner:

[0062] Adjust the pH value of the mixture of the first separation liquid and the alkali to 7 to 8 to precipitate nickel; after separating out the nickel precipitate, adjust the pH value of the remaining mixture to 8.5 - 9.5 to precipitate cobalt. If Z also includes manganese, after the above cobalt precipitation operation, the cobalt precipitate can be separated out, and then the pH value of the remaining mixture can be adjusted to 10 - 11 to precipitate manganese.

[0063] In some embodiments, Z only contains nickel or cobalt or manganese. At this time, the mixture of the first separation liquid and the alkali can be adjusted to the pH value range required for the corresponding element to form a precipitate with reference to the above method.

[0064] It should be noted that the main component of the laterite nickel ore acid leaching residue (i.e., the first separation residue) is iron. At present, some methods for treating the acid leaching residue are to directly magnetize and roast the first separation residue to convert the iron oxide in the acid leaching residue into magnetic iron tetroxide, and then recover and utilize the metallic iron through magnetic separation. However, this method is difficult to separate iron and aluminum, resulting in a high aluminum content in the iron concentrate and unable to meet the use standard of the iron concentrate.

[0065] In the present disclosure, the inventors creatively proposed the following method, which can effectively separate iron and aluminum: roast the first separation residue to decompose alum or potassium alum to generate aluminum hydroxide or aluminum oxide, then mix the roasted material with water for water washing, and perform a second solid-liquid separation on the water-washed slurry to obtain a second separation residue containing iron and a second separation liquid containing aluminum.

[0066] In some embodiments, the first separation residue is first dried and then roasted.

[0067] For reference, the roasting temperature can be 200°C - 500°C, such as 200°C, 250°C, 300°C, 350°C, 400°C, 450°C or 500°C, etc., or any other value within the range of 200°C - 500°C.

[0068] The roasting time can be 1h - 3h, such as 1h, 1.5h, 2h, 2.5h or 3h, etc., or any other value within the range of 1h - 3h.

[0069] By calcining within the above temperature range, alumopharmacosiderite or alum can undergo decomposition reactions to generate aluminum oxide or aluminum hydroxide, and their corresponding reaction equations include:

[0070] 2(H3O)Al3(OH)6(SO4)2(s) → 3Al2O3 + 4SO3 + 9H2O;

[0071] 2MAl3(SO4)2(OH)6(s) → M2SO4 + Al2(SO4)3 + 4Al(OH)3.

[0072] It should be noted that if the calcination temperature is higher than 500 °C, the aluminum obtained from the decomposition reaction will react with iron to form ferroaluminate, making it impossible to separate aluminum from iron. If the calcination temperature is lower than 200 °C, the above decomposition reactions of alumopharmacosiderite or alum cannot occur. The present disclosure controls the calcination temperature within 200 °C - 500 °C, ensuring that the decomposition reaction temperature of alumopharmacosiderite or alum is reached while avoiding the formation temperature of ferroaluminate.

[0073] In some embodiments, after calcination, it is cooled to room temperature, and then the material obtained from calcination (referred to as "calcined slag") is mixed with water for water washing to obtain a water-washed slurry.

[0074] For reference, the solid-liquid ratio in the water washing process can be 1 g:3 mL - 1 g:6 mL, such as 1 g:3 mL, 1 g:3.5 mL, 1 g:4 mL, 1 g:4.5 mL, 1 g:5 mL, 1 g:5.5 mL or 1 g:6 mL, etc., or any other arbitrary value within the range of 1 g:3 mL - 1 g:6 mL.

[0075] In some embodiments, the water washing process can be carried out under stirring conditions. The stirring speed can be, for example, 350 r / min - 400 r / min, such as 350 r / min, 360 r / min, 370 r / min, 380 r / min, 390 r / min or 400 r / min, etc.

[0076] The water-washed slurry obtained by water washing is weakly acidic (pH value is about 4.5). Iron exists in the form of ions when the pH value < 2; it starts to precipitate when the pH value = 2; it precipitates completely when the pH value is around 4; when the pH value > 4, iron exists in the form of solid precipitation. Therefore, in the water-washed slurry, aluminum ions exist in the form of aluminum sulfate, and iron ions still exist in the slag in the form of precipitation. The separation of aluminum and iron can be achieved through the second solid-liquid separation (such as filtration, etc.). At this time, aluminum is mainly in the second separation liquid, and iron is mainly in the second separation slag.

[0077] In some embodiments, after the second solid-liquid separation, it further includes: reacting the second separation liquid with an alkali to obtain aluminum hydroxide.

[0078] Similarly, the base may be exemplified by NaOH or KOH.

[0079] Furthermore, the second separated slag is subjected to reduction roasting and magnetic separation to obtain quartz sand and iron concentrate.

[0080] In some embodiments, the second separated slag is first dried and then reduction roasted.

[0081] For reference, reduction roasting can be roasting the second separated slag with a non-metallic reagent having reducing properties, and the process can be carried out in a muffle furnace.

[0082] The above reduction roasting process is mainly used to reduce ferric iron to magnetic iron (such as elemental iron and substances containing ferrous iron). The reaction equation involved includes: 6Fe2O3+C=4Fe3O4+CO2.

[0083] The temperature of the reduction roasting may be 800°C-1000°C, such as 800°C, 850°C, 900°C, 950°C or 1000°C, or any other value within the range of 800°C-1000°C.

[0084] It should be noted that if the reduction roasting temperature is lower than 800°C, the effect of reducing the trivalent iron substance in the second separation slag cannot be achieved; if the reduction roasting temperature is higher than 1000°C, the trivalent iron substance in the second separation slag will melt and form a form similar to molten iron.

[0085] The reduction roasting time may be 30 min-60 min, such as 30 min, 35 min, 40 min, 45 min, 50 min or 60 min, etc., or any other value within the range of 30 min-60 min.

[0086] For reference, the mass of the above-mentioned reducing non-metallic reagent can be 10%-20% of the second separation slag, such as 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, etc., or it can be any other value within the range of 10%-20%.

[0087] It should be noted that if the amount of the reducing non-metallic reagent is too small, less trivalent iron can be reduced to magnetic iron, resulting in a lower recovery rate of magnetic iron; if the amount of the reducing non-metallic reagent is too large, the cost will increase.

[0088] In some embodiments, the non-metallic reagent having reducing properties may include, for example, at least one of carbon powder, biochar, and reducing organic matter.

[0089] Among them, the biochar may exemplarily but not limitedly include at least one of wood chips and straw. The reducing organic matter may exemplarily but not limitedly include at least one of glucose, sucrose, cellulose, fructose, lactose, maltose, ribose, and xylooligosaccharide.

[0090] After reduction roasting, magnetic separation can be carried out in a magnetic separator. The magnetic substances are fixed in the magnetic area of the magnetic separator during the magnetic separation process, and the non-magnetic substances are removed.

[0091] Exemplarily, the exciting current intensity used for magnetic separation can be 0.6A - 1.5A, such as 0.6A, 0.7A, 0.8A, 0.9A, 1.0A, 1.1A, 1.2A, 1.3A, 1.4A, or 1.5A, etc., or any other arbitrary value within the range of 0.6A - 1.5A.

[0092] In some embodiments, before magnetic separation, the substances after reduction roasting can also be ground to grind fine the substances that may agglomerate into blocks during reduction roasting, thereby facilitating the magnetic separation process. Exemplarily, the substances after reduction roasting can be ground to 200 meshes.

[0093] As mentioned above, the method for resource utilization of laterite nickel ore provided by the present disclosure makes full use of the characteristic that the aqueous solution of the high-pressure acid leaching residue of laterite nickel ore is acidic. Through the way of low-temperature roasting combined with water washing, the aluminum generated by the hydrolysis reaction is re-enriched into the filtrate, realizing the separation of iron and aluminum. There is no need to add acid or alkali for leaching treatment of the leaching residue, saving costs and reducing the difficulty of subsequent wastewater treatment. In addition, the method provided by the present disclosure not only realizes the recycling of iron and aluminum, but also realizes the recycling of silicon dioxide, obtaining low-grade quartz sand products. By adopting a shorter treatment process and under the condition of smaller operation difficulty, the separation of silicon, aluminum, and iron in the acid leaching residue of laterite nickel ore is effectively realized, and the resource utilization of the acid leaching residue is fully realized.

[0094] The features and properties of the present disclosure will be further described in detail below in conjunction with the embodiments.

[0095] Example 1

[0096] This example provides a method for resource utilization of laterite nickel ore. Please refer to Figure 1 , which includes the following steps:

[0097] Step (1): High-pressure acid leaching process.

[0098] After mixing laterite nickel ore (from Guangdong Bump Recycling Technology Co., Ltd.) evenly with sulfuric acid solution, high-pressure leaching is carried out in an autoclave. After the leaching is completed, filtration is carried out to obtain a first separation liquid (nickel-containing filtrate) and a first separation residue (iron-containing filter residue). The first separation liquid is mixed with sodium hydroxide, and the pH value of the mixture is adjusted to 7.5. After the reaction, filtration is carried out to obtain nickel hydroxide; the pH value of the remaining mixture is adjusted to 9, and after the reaction, filtration is carried out to obtain cobalt hydroxide.

[0099] The concentration of the above sulfuric acid solution is 160 g / L, and the mass ratio of the sulfuric acid solution to the laterite nickel ore is 2:1. The pressure of the high-pressure acid leaching is 2 MPa, the temperature of the high-pressure acid leaching is 200 °C, and the time of the high-pressure acid leaching is 3 h.

[0100] Step (2): Roasting and washing process.

[0101] The first separation residue is dried and then subjected to low-temperature roasting to obtain a roasted residue. Subsequently, it is cooled to room temperature, and the roasted residue is washed with water and filtered to obtain a second separation liquid and a second separation residue. The second separation liquid is reacted with sodium hydroxide to obtain aluminum hydroxide products.

[0102] The temperature of the above low-temperature roasting is 250 °C, and the roasting time is 2 h. During the washing process, the solid-liquid ratio of the roasted residue to water is 1 g:3 mL, and the washing process is carried out under the condition that the stirring speed is 350 r / min.

[0103] Step (3): Reduction roasting process.

[0104] The second separation residue is dried and then mixed with carbon powder, and reduction roasting is carried out in a muffle furnace.

[0105] The dosage of the above carbon powder is 12 wt% of the second separation residue, the temperature of the reduction roasting is 900 °C, and the time of the reduction roasting is 40 min.

[0106] Step (4): Magnetic separation process.

[0107] The roasted residue obtained by reduction roasting is ground to 200 mesh, and then mixed with water and fed into a magnetic separator. Magnetic separation is carried out under the condition that the exciting current intensity is 1.0 A, so that the magnetic iron substances with magnetism are adsorbed on the magnetic area of the magnetic separator, and the substances such as silicon without magnetism flow out of the magnetic separator, so as to obtain iron concentrate and low-iron quartz respectively.

[0108] Example 2

[0109] The difference between this example and Example 1 is that in step (3), the dosage of carbon powder is 15 wt% of the second separation residue.

[0110] Example 3

[0111] The difference between this embodiment and Embodiment 1 is that in step (3), the dosage of carbon powder is 18 wt% of the second separation residue.

[0112] Embodiment 4

[0113] The difference between this embodiment and Embodiment 1 is that in step (3), the dosage of carbon powder is 20 wt% of the second separation residue.

[0114] Embodiment 5

[0115] This embodiment provides a method for resource utilization of laterite nickel ore, including the following steps:

[0116] Step (1): High-pressure acid leaching process.

[0117] After mixing the laterite nickel ore (the same as in Embodiment 1) with the sulfuric acid solution evenly, high-pressure leaching is carried out in an autoclave. After the leaching is completed, filtration is carried out to obtain the first separation liquid (nickel-containing filtrate) and the first separation residue (iron-containing filter residue). The first separation liquid is mixed with sodium hydroxide, and the pH value of the mixture is adjusted to 7. After reaction, filtration is carried out to obtain nickel hydroxide; the pH value of the remaining mixture is adjusted to 9.5, and after reaction, filtration is carried out to obtain cobalt hydroxide.

[0118] The concentration of the above sulfuric acid solution is 140 g / L, and the mass ratio of the sulfuric acid solution to the laterite nickel ore is 3:1. The pressure of high-pressure acid leaching is 2.2 MPa, the temperature of high-pressure acid leaching is 225 °C, and the time of high-pressure acid leaching is 4 h.

[0119] Step (2): Roasting and water washing process.

[0120] The first separation residue is dried and then subjected to low-temperature roasting to obtain a roasted residue. Subsequently, it is cooled to room temperature, and the roasted residue is washed with water and filtered to obtain a second separation liquid and a second separation residue. The second separation liquid is reacted with sodium hydroxide to obtain an aluminum hydroxide product.

[0121] The temperature of the above low-temperature roasting is 200 °C, and the roasting time is 3 h. During the water washing process, the solid-liquid ratio of the roasted residue to water is 1 g:4.5 mL, and the water washing process is carried out under the condition of a stirring speed of 380 r / min.

[0122] Step (3): Reduction roasting process.

[0123] The second separation residue is dried and then mixed with glucose, and reduction roasting is carried out in a muffle furnace.

[0124] The dosage of the above glucose is 15 wt% of the second separation residue, the temperature of reduction roasting is 800 °C, and the time of reduction roasting is 60 min.

[0125] Step (4): Magnetic separation process.

[0126] The calcined slag obtained by reduction roasting is ground to 200 mesh, then mixed with water and fed into a magnetic separator. Magnetic separation is carried out under the condition that the exciting current intensity is 0.6 A, so that the magnetic iron substances with magnetism are adsorbed on the magnetic area of the magnetic separator, and substances such as silicon without magnetism flow out of the magnetic separator, thereby obtaining iron concentrate and low-iron quartz respectively.

[0127] Example 6

[0128] This example provides a method for the resource utilization of laterite nickel ore, including the following steps:

[0129] Step (1): High-pressure acid leaching process.

[0130] After uniformly mixing the laterite nickel ore (the same as in Example 1) with the sulfuric acid solution, high-pressure leaching is carried out in an autoclave. After the leaching is completed, filtration is carried out to obtain the first separation liquid (nickel-containing filtrate) and the first separation residue (iron-containing filter residue). The first separation liquid is mixed with sodium hydroxide, and the pH value of the mixture is adjusted to 7.5. After reaction, filtration is carried out to obtain nickel hydroxide; the pH value of the remaining mixture is adjusted to 9, and after reaction, filtration is carried out to obtain cobalt hydroxide.

[0131] The concentration of the above sulfuric acid solution is 180 g / L, and the mass ratio of the sulfuric acid solution to the laterite nickel ore is 4:1. The pressure of high-pressure acid leaching is 2.3 MPa, the temperature of high-pressure acid leaching is 250 °C, and the time of high-pressure acid leaching is 2 h.

[0132] Step (2): Roasting and water washing process.

[0133] The first separation residue is dried and then subjected to low-temperature roasting to obtain a calcined slag. Subsequently, it is cooled to room temperature, and the calcined slag is washed with water and filtered to obtain a second separation liquid and a second separation residue. The second separation liquid is reacted with sodium hydroxide to obtain an aluminum hydroxide product.

[0134] The temperature of the above low-temperature roasting is 500 °C, and the roasting time is 1 h. During the water washing process, the solid-liquid ratio of the calcined slag to water is 1 g:6 mL, and the water washing process is carried out under the condition that the stirring speed is 400 r / min.

[0135] Step (3): Reduction roasting process.

[0136] The second separation residue is dried and then mixed with straw, and reduction roasting is carried out in a muffle furnace.

[0137] The dosage of the above straw is 15 wt% of the second separation residue, the temperature of reduction roasting is 1000 °C, and the time of reduction roasting is 30 min.

[0138] Step (4): Magnetic separation process.

[0139] The calcined slag obtained by reduction roasting is ground to 200 mesh, then mixed with water and fed into a magnetic separator, and magnetic separation is carried out under the condition that the exciting current intensity is 1.5 A, so that the magnetic iron substances with magnetism are adsorbed on the magnetic area of the magnetic separator, and substances such as silicon without magnetism flow out of the magnetic separator, thereby obtaining iron concentrate and low-iron quartz respectively.

[0140] Comparative Example 1

[0141] The difference between this comparative example and Example 3 is that: the roasting and water washing process in step (2) is not carried out, and the first separated slag obtained in step (1) is directly processed in step (3) and step (4).

[0142] Comparative Example 2

[0143] The difference between this comparative example and Example 3 is that: in step (2), the roasting temperature is 150 °C.

[0144] Comparative Example 3

[0145] The difference between this comparative example and Example 3 is that: in step (2), the roasting temperature is 600 °C.

[0146] Comparative Example 4

[0147] The difference between this comparative example and Example 3 is that: in step (3), the dosage of carbon powder is 5 wt% of the second separated slag.

[0148] Comparative Example 5

[0149] The difference between this comparative example and Example 3 is that: in step (3), the dosage of carbon powder is 25 wt% of the second separated slag.

[0150] Comparative Example 6

[0151] The difference between this comparative example and Example 3 is that: in step (3), the reduction roasting temperature is 700 °C.

[0152] Comparative Example 7

[0153] The difference between this comparative example and Example 3 is that: in step (3), the reduction roasting temperature is 1100 °C.

[0154] It should be noted that the roasting temperature of Comparative Example 7 is too high, resulting in the products sticking together, difficult to grind, and poor magnetic separation effect.

[0155] Test Example

[0156] The iron grade, iron concentrate yield, iron recovery rate, aluminum recovery rate, and silicon recovery rate of the methods provided in Examples 1-6 and Comparative Examples 1-6 were compared. The specific element data was tested by ICP-AES equipment, and the results are shown in Table 1.

[0157] Among them, the iron grade refers to the mass percentage of iron in the iron concentrate. The yield of iron concentrate refers to the percentage of iron concentrate in the high-pressure acid leaching residue. The iron recovery rate refers to the percentage of the mass of iron in the iron concentrate in the total iron in the high-pressure acid leaching residue, the aluminum recovery rate refers to the percentage of the mass of aluminum in the high-pressure acid leaching residue, and the silicon recovery rate refers to the percentage of the mass of silicon in the high-pressure acid leaching residue. For example: the mass of the high-pressure acid leaching residue is m, the iron grade (mass percentage) is x, the aluminum grade is y, and the silicon grade is z; the mass of the obtained iron concentrate is m1, and the iron grade is x1; the mass of aluminum hydroxide is m2, and the aluminum grade is y1; the mass of the obtained quartz sand is m3, and the silicon grade is z1; then the calculation formulas are as follows:

[0158] Yield of iron concentrate = m1 / m;

[0159] Iron recovery rate = (m1 × x1) / (m × x) × 100%;

[0160] Aluminum recovery rate = (m2 × y1) / (m × y) × 100%;

[0161] Silicon recovery rate = (m3 × z1) / (m × z) × 100%.

[0162] Table 1 Comparison results

[0163] Iron grade / % Yield of iron concentrate / % Iron recovery rate / % Aluminum recovery rate / % Silicon recovery rate / % Example 1 60.02 58.03 74.07 85.23 86.25 Example 2 62.15 60.01 79.35 85.23 87.45 Example 3 64.23 62.38 84.57 85.23 89.34 Example 4 66.25 64.58 86.75 85.23 90.23 Example 5 58.23 56.79 70.89 83.43 85.31 Example 6 62.13 59.63 78.49 86.45 86.74 Comparative Example 1 50.32 50.41 63.71 50.25 70.23 Comparative Example 2 54.36 53.48 67.89 53.45 73.45 Comparative Example 3 50.78 50.76 65.76 50.25 70.34 Comparative Example 4 40.23 48.36 48.59 85.23 68.79 Comparative Example 5 63.45 56.23 65.23 85.23 69.73 Comparative Example 6 58.64 55.23 68.41 85.23 68.74

[0164] As can be seen from Table 1, the method provided by the present disclosure can effectively separate silicon, aluminum, and iron in the acid leaching residue of laterite nickel ore, with low cost and high recovery rates of iron, aluminum, and silicon.

[0165] Industrial applicability

[0166] The laterite nickel ore resource utilization method provided by the present disclosure has a short treatment process, low operation difficulty, and low treatment cost, effectively separates silicon, aluminum, and iron in the acid leaching residue of laterite nickel ore, and fully realizes the resource utilization of the acid leaching residue.

Claims

1. A method for resource utilization of laterite nickel ore, characterized in that: The following steps are involved: The laterite nickel ore is subjected to high-pressure acid leaching, and the solid-liquid mixture obtained from the high-pressure acid leaching is subjected to the first solid-liquid separation to obtain a first separation liquid and a first separation residue containing magnetite and alunite or alum-potassium alum; wherein, the alum-potassium alum is (H3O)Al3(OH)6(SO4)2, the alunite is MAl3(SO4)2(OH)6, and M is Na + , K + and NH4 + at least one of them; calcining the first separation slag to decompose alum or alum to produce aluminum hydroxide or aluminum oxide, then mixing the calcined material with water for washing, and subjecting the washed slurry to a second solid-liquid separation to obtain a second separation slag containing iron and a second separation liquid containing aluminum; The second separated slag is subjected to reduction roasting and magnetic separation to obtain quartz sand and iron concentrate; The calcination temperature is 200℃-500℃; The reduction roasting is to roast the second separated slag with a non-metallic reagent having reducing properties; the temperature of the reduction roasting is 800° C.-1000° C.; The mass of the reducing non-metallic reagent is 10%-20% of the second separation residue; the reducing non-metallic reagent includes at least one of carbon powder, biochar and reducing organic matter; the reducing organic matter includes at least one of glucose, sucrose, cellulose, fructose, lactose, maltose, ribose and oligoxylose.

2. The method for resource utilization of laterite nickel ore according to claim 1, characterized in that The pressure of high-pressure acid leaching is 2-2.3MPa.

3. The method for resource utilization of laterite nickel ore according to claim 2, characterized in that: The temperature of high pressure acid leaching is 200℃-250℃.

4. The method for resource utilization of laterite nickel ore according to claim 3, wherein The high pressure acid leaching time is 2h-4h.

5. The method for resource utilization of laterite nickel ore according to claim 4, characterized in that: High-pressure acidification is to react the laterite nickel ore with an acid solution, wherein the acid solution includes at least one of a sulfuric acid solution, a hydrochloric acid solution and a nitric acid solution.

6. The method for resource utilization of laterite nickel ore according to claim 5, characterized in that: The mass ratio of the laterite nickel ore to the acid solution is 1:2-1:4, and the concentration of the acid solution is 140g / L-180g / L.

7. The method for resource utilization of laterite nickel ore according to claim 1, characterized in that When the laterite nickel ore contains element Z, after the first solid-liquid separation, the method further comprises: reacting the first separated liquid with an alkali to obtain a corresponding hydroxide precipitate of Z; Wherein, Z is at least one element selected from the group consisting of cobalt, nickel and manganese.

8. The method for resource utilization of laterite nickel ore according to claim 1, wherein The calcination time is 1h-3h.

9. The method for resource utilization of laterite nickel ore according to claim 1, characterized in that The solid-liquid ratio of the water washing process is 1g:3mL-1g:6mL.

10. The method for resource utilization of laterite nickel ore according to claim 1, characterized in that: The water washing process is carried out under stirring conditions.

11. The method for resource utilization of laterite nickel ore according to claim 10, characterized in that: The stirring speed is 350r / min-400r / min.

12. The method for resource utilization of laterite nickel ore according to claim 1, characterized in that: After the second solid-liquid separation, the method further includes: reacting the second separated liquid with an alkali to obtain aluminum hydroxide.

13. The method for resource utilization of laterite nickel ore according to claim 1, characterized in that, The reduction roasting time is 30min-60min.

14. The method for resource utilization of laterite nickel ore according to claim 1, characterized in that: The biochar includes at least one of wood chips and straw.

15. The method for resource utilization of laterite nickel ore according to claim 1, characterized in that, The intensity of the exciting current used for magnetic separation is 0.6A-1.5A.

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