Method for treating high-pressure leached pulp

Abstract

The invention discloses a method for treating high-pressure leached ore pulp, which comprises the following steps of: performing continuous countercurrent washing treatment (CCD) on the high-pressure leached ore pulp to obtain leached ore pulp overflow; a neutralizing agent and the leaching ore pulp overflow are subjected to pre-neutralization treatment, so that pre-neutralized ore pulp is obtained; and the pre-neutralized ore pulp is subjected to iron and aluminum removal treatment, so that iron and aluminum slag and iron and aluminum removed leaching liquid are obtained. According to the method, the laterite-nickel ore is subjected to high-pressure acid leaching treatment to obtain high-pressure leached ore pulp, the high-pressure leached ore pulp is subjected to CCD (Charge Coupled Device), the laterite-nickel ore leached residues are separated into leached ore pulp underflow, and then the leached ore pulp overflow is subjected to pre-neutralization treatment, so that the separation of the laterite-nickel ore leached residues and the pre-neutralized ore pulp is realized; conditions are created for resource utilization of the laterite-nickel ore leaching residues and tailings obtained by further treatment of pre-neutralized ore pulp obtained after pre-neutralization treatment.

Description

Technical Field

[0001] The present application relates to the field of hydrometallurgy, and in particular, to a method for treating high-pressure leaching slurry. Background Art

[0002] With the continuous consumption of nickel ore resources, the reserves of nickel-rich ore of proven nickel sulfide ores are getting smaller and smaller worldwide. Therefore, the development and utilization of nickel-poor laterite nickel ore will become more and more important. The grade of laterite nickel ore is low, and a smelting process of pyrometallurgy or hydrometallurgy is required to obtain high-grade nickel intermediate products. When hydrometallurgy of laterite nickel ore is used to obtain nickel metal, a large amount of tailings will also be produced, resulting in an increase in the production cost of smelting laterite nickel ore, as well as difficulties in recycling and treating wastewater and waste residue. How to utilize laterite nickel ore resources more comprehensively and efficiently is one of the research directions in this field. Summary of the invention

[0003] In the first aspect of the present application, the present application proposes a method for treating high-pressure leaching slurry, comprising: performing continuous countercurrent washing treatment (CCD) on the high-pressure leaching slurry to obtain a leaching slurry overflow; pre-neutralizing the leaching slurry overflow with a neutralizing agent to obtain a pre-neutralized slurry; and removing iron and aluminum from the pre-neutralized slurry to obtain iron-aluminum slag and an iron-aluminum-removed leaching liquid.

[0004] The method for treating high-pressure leaching slurry proposed in the present application first performs CCD on the high-pressure leaching slurry obtained after high-pressure acid leaching of laterite nickel ore, separates the laterite nickel ore leaching residue into the leaching slurry underflow, and then pre-neutralizes the leaching slurry overflow, thereby realizing the separation of the laterite nickel ore leaching residue and the pre-neutralized slurry, and creating conditions for the resource utilization of the tailings obtained by further treating the laterite nickel ore leaching residue and the pre-neutralized slurry obtained after the pre-neutralization treatment.

[0005] In some embodiments, the pH value of the pre-neutralized slurry is 1.0-3.0. Thus, the pH value of the leaching slurry overflow can be adjusted and gypsum precipitation can be generated.

[0006] In some embodiments, the number of stages of the continuous countercurrent washing treatment is 3 to 8. Thus, the laterite nickel ore leaching residue in the high-pressure leaching slurry can be separated into the leaching slurry underflow, while reducing the content of valuable metal ions therein.

[0007] In some embodiments, the neutralizing agent includes at least one of quicklime, calcium carbonate, and calcium hydroxide. Thus, the pH value of the high-pressure leaching slurry can be adjusted by using the neutralizing agent.

[0008] In some embodiments, after the leaching slurry overflow is subjected to the pre-neutralization treatment, the process further comprises: performing a thickening treatment on 50%-95% by mass of the pre-neutralized slurry to obtain a pre-neutralized underflow and a pre-neutralized overflow, thereby separating the gypsum precipitate in the pre-neutralized slurry and concentrating the metal ions in the pre-neutralized slurry.

[0009] In some embodiments, the method further comprises: mixing the pre-neutralization underflow with the leaching slurry overflow; and performing the iron and aluminum removal treatment on the pre-neutralization overflow. Thus, the gypsum precipitate formed in the pre-neutralization slurry is returned and mixed with the leaching slurry overflow, providing a template for crystal growth for the newly generated gypsum in the leaching slurry overflow, which is beneficial to obtaining a larger gypsum particle size, and further beneficial to tailings treatment.

[0010] In some embodiments, the method further comprises: subjecting the neutralizing agent to tailings neutralization treatment with the iron-aluminum slag to obtain tailings neutralization overflow and tailings, thereby achieving adjustment and concentration of the pH value of the tailings.

[0011] In some embodiments, the process further comprises: subjecting the tailings to filter press treatment, thereby achieving a better solid-liquid separation effect on the tailings.

[0012] In some embodiments, the pH value of the tailings neutralization and overflow is 6.0-9.0. Thus, the pH value of the tailings neutralization and overflow is close to neutral, meeting the environmental protection requirements for wastewater discharge.

[0013] In some embodiments, the pH value of the iron-removing aluminum leaching solution is 3.0-5.0, thereby reducing the content of iron and aluminum in the iron-removing aluminum leaching solution.

[0014] In some embodiments, the method further comprises: subjecting the iron-aluminum-removed leaching solution to nickel-cobalt precipitation to obtain a nickel-cobalt product, thereby precipitating and collecting nickel and cobalt elements in the laterite nickel ore. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0016] Figure 1 This is a schematic flow chart of a method for treating high-pressure leaching slurry in one embodiment of the present application;

[0017] Figure 2 This is a schematic flow chart of a method for treating high-pressure leaching slurry in another embodiment of the present application. DETAILED DESCRIPTION

[0018] The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the drawings, but unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of actually identical structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0019] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field to which this application belongs; the terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application; unless otherwise specified, the numerical values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (for example, they can be tested according to the methods given in the embodiments of this application).

[0020] The terms "including" and "having" in the specification and claims of the present application and any modifications thereof are open expressions, that is, including the contents specified in the present application but not excluding other contents.

[0021] In the description of this application, regardless of whether the words "about" or "approximately" are used, all the numbers disclosed herein are approximate values. The value of each number may differ by less than 10% or a reasonable difference considered by those skilled in the art, such as 1%, 2%, 3%, 4% or 5%.

[0022] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0023] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0024] In the hydrometallurgical process of laterite nickel ore, high pressure acid leaching (HPAL) process is a commonly used method for extracting nickel and cobalt metals from laterite nickel ore. Due to the variable composition of laterite nickel ore, the acid content and metal ion concentration in the high pressure leached slurry obtained after high pressure acid leaching treatment fluctuate within a certain range. Laterite nickel ore is a lean ore, and a large amount of tailings is produced after hydrometallurgy. Tailings treatment methods include deep sea landfill, wet slag storage, dry slag storage, etc., among which dry slag storage is the most widely used. Before dry slag storage of tailings, it is necessary to reduce the water content in the tailings as much as possible, which can reduce the storage space and facilitate the further utilization of tailings. In addition, the tailings contain a large amount of iron elements, which have economic value. Realizing the resource utilization of tailings will be of great significance to the laterite nickel ore hydrometallurgical industry.

[0025] In the first aspect of the present application, the present application proposes a method for treating high-pressure leaching pulp, comprising: performing continuous countercurrent washing (CCD) on the high-pressure leaching pulp to obtain a leaching pulp overflow; pre-neutralizing the leaching pulp overflow with a neutralizing agent to obtain a pre-neutralized pulp; and performing iron-aluminum removal treatment on the pre-neutralized pulp to obtain iron-aluminum slag and iron-aluminum removal leachate. The method for treating high-pressure leaching pulp proposed in the present application, refer to Figure 1 , the high-pressure leaching pulp obtained after high-pressure acid leaching of laterite nickel ore is passed through CCD, and in the CCD process, by adding additives such as flocculants, the high-pressure leaching pulp obtained after high-pressure acid leaching of laterite nickel ore is first subjected to CCD, and the laterite nickel ore leaching residue is separated into the leaching pulp bottom flow, and then the leaching pulp overflow is pre-neutralized, so as to achieve the separation of the laterite nickel ore leaching residue and the pre-neutralized pulp, and create conditions for the resource utilization of the tailings obtained by further processing the laterite nickel ore leaching residue and the pre-neutralized pulp obtained after the pre-neutralization treatment. In addition, the pre-neutralized pulp obtained after the pre-neutralization treatment has a higher pH value than the high-pressure leaching pulp, which is conducive to the formation of raw gypsum by calcium ions in the neutralizer and sulfate ions in the high-pressure leaching pulp.

[0026] In some embodiments, the pH value of the pre-neutralized slurry is 1.0-3.0. Thus, the pH value of the leaching slurry overflow can be adjusted and gypsum precipitation can be generated.

[0027] In some embodiments, the raw gypsum includes at least one of calcium sulfate, calcium hydrogen sulfate, calcium sulfate dihydrate, and calcium sulfate hemihydrate.

[0028] In some embodiments, the number of stages of the continuous countercurrent washing treatment is 3 to 8. Thus, the laterite nickel ore leaching residue in the high-pressure leaching slurry can be separated into the leaching slurry underflow, while reducing the content of valuable metal ions therein.

[0029] In some embodiments, the neutralizing agent includes at least one of quicklime, calcium carbonate, and calcium hydroxide. Thus, the neutralizing agent can adjust the pH value of the high-pressure leaching pulp, and can introduce calcium ions to react with sulfate ions introduced by high-pressure acid leaching treatment to generate gypsum, thereby precipitating sulfate ions.

[0030] In some embodiments, the iron and aluminum removal process may include: a first iron and aluminum removal process and a second iron and aluminum removal process. Thus, the iron and aluminum elements may be precipitated in stages to adjust the iron and aluminum removal process according to the different compositions of the iron and aluminum components in the laterite nickel ore.

[0031] In some embodiments, after the leaching slurry overflow is subjected to the pre-neutralization treatment, the process further comprises: thickening 50%-95% by mass of the pre-neutralized slurry to obtain a pre-neutralization underflow and a pre-neutralization overflow. Figure 2 After the leaching slurry overflow is pre-neutralized, its pH value rises, and the calcium ions in the neutralizer react with the sulfate ions in the leaching slurry overflow to generate raw gypsum and precipitate. Through the thickening treatment, the generated raw gypsum can be separated and concentrated into the pre-neutralization underflow, and the metal ions in the pre-neutralized slurry can be concentrated into the pre-neutralization overflow.

[0032] In some embodiments, 5%-50% by mass of the pre-neutralized slurry is treated to remove iron and aluminum.

[0033] In some embodiments, it further includes: mixing the pre-neutralization underflow with the leaching slurry overflow; and performing the iron and aluminum removal treatment on the pre-neutralization overflow.

[0034] After the overflow of the leached slurry is pre-neutralized separately, the underflow circulation is completed by returning the pre-neutralized underflow and mixing it with the overflow of the leached slurry that is still undergoing pre-neutralization. The calcium sulfate in the leachate can use the gypsum crystals brought by the pre-neutralized underflow as a template to continue to grow on the surface of the gypsum crystals, thereby increasing the particle size of the gypsum crystals to obtain gypsum crystals with a particle size greater than or equal to 20μm. At the same time, after the high-pressure leaching slurry passes through CCD, the metal ion concentration and acid concentration therein are significantly reduced compared to the high-pressure leaching slurry, and the relatively neutral environment is also conducive to the formation and particle size growth of gypsum particles. The larger particle size of the gypsum particles is conducive to improving the slag properties of the tailings, improving the tailings filter pressure efficiency, reducing the tailings moisture content, and thereby improving the tailings storage efficiency.

[0035] In some embodiments, the method further comprises: subjecting the neutralizing agent and the iron-aluminum slag to a tailings neutralization treatment to obtain a tailings neutralization overflow and tailings.

[0036] During the iron and aluminum removal process, a neutralizing agent is added to allow the iron and aluminum ions to reach the pH range for precipitation. After the iron and aluminum removal treatment is completed, the pH value of the iron and aluminum removal leaching solution obtained is 3.0-5.0, and the iron-aluminum slag obtained also has a certain water content and is acidic. If the iron-aluminum slag is directly piled up or backfilled in this case, it will cause corrosion and pollution to the environment and facilities. Therefore, it is necessary to further adjust the pH value of the iron-aluminum slag, and separate the water in the iron-aluminum slag to obtain tailings and tailings neutralization overflow. Among them, the pH value of the tailings neutralization overflow is close to neutral, which can be discharged or purified, and the tailings can be further processed or utilized.

[0037] In some embodiments, the leached slurry bottom flow obtained by continuous countercurrent washing can be treated with iron-aluminum slag and a neutralizer to perform tailings neutralization treatment to obtain tailings neutralization overflow and tailings. Thus, the pH value of the laterite nickel ore leaching slag contained in the leached slurry bottom flow obtained by continuous countercurrent washing can be adjusted, and solid-liquid separation can be performed to obtain tailings and tailings neutralization overflow. In some embodiments, it further includes: the tailings are subjected to filter press treatment.

[0038] By returning the pre-neutralization underflow to the leaching slurry overflow, the particle size of the raw gypsum crystals in the tailings is made larger. The larger particles have a larger volume and mass, and the sedimentation speed is faster. The larger particles are more easily intercepted by the filter medium, which improves the filtration efficiency. Therefore, under the same filter press treatment conditions, the tailings filter press treatment time can be shortened to achieve a better solid-liquid separation effect. The tailings obtained by solid-liquid separation of the solids in the iron-aluminum slag still contain a certain amount of water. The tailings can be further reduced by filter press treatment. The tailings with less water content are easier to store or backfill, reducing the required space, which is conducive to reducing the processing or storage costs, so as to improve the economic benefits of the overall treatment method.

[0039] In some embodiments, the feed pressure of the filter press treatment is 6 bar-7 bar, and the extrusion pressure is 7 bar-8 bar.

[0040] In some embodiments, the pH value of the tailings neutralization overflow is 6.0-9.0. Therefore, the pH value of the tailings neutralization overflow is close to neutral, and the corrosion of the waste liquid treatment is low, which can comprehensively reduce the impact of laterite nickel ore smelting on the environment.

[0041] In some embodiments, the pH value of the de-iron-aluminum leachate is 3.0-5.0. Thus, the iron and aluminum elements in the de-iron-aluminum leachate have been fully precipitated, and the iron and aluminum elements can be separated from the de-iron-aluminum leachate containing nickel and cobalt elements through subsequent solid-liquid separation to obtain a nickel-cobalt product through nickel-cobalt precipitation.

[0042] In some embodiments, the method further comprises: subjecting the iron-aluminum-removed leaching solution to nickel-cobalt precipitation to obtain a nickel-cobalt product. Thus, the nickel and cobalt elements in the laterite nickel ore can be precipitated to obtain a nickel-cobalt product with higher purity.

[0043] The scheme of the present application is described below by specific examples. It should be noted that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If no specific technology or conditions are specified in the examples, the technology or conditions described in the literature in this area or the product instructions are used. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be obtained commercially.

[0044] Example 1

[0045] The high-pressure leaching pulp of laterite nickel ore is subjected to solid-liquid separation by using a 6-stage CCD to obtain the leaching pulp overflow and the leaching pulp underflow;

[0046] The leached slurry overflow is pre-neutralized to obtain a pre-neutralized slurry, wherein the pre-neutralization treatment time is 4 hours, and the pH value of the pre-neutralized slurry is 1.8;

[0047] The pre-neutralized slurry is subjected to a first iron-aluminum removal treatment and a second iron-aluminum removal treatment to obtain an iron-aluminum removal leaching solution and iron-aluminum slag, wherein the iron-aluminum removal treatment time is 5 hours, and the pH value of the iron-aluminum removal leaching solution is 4.7;

[0048] After solid-liquid separation and washing, the iron-aluminum slag is treated with a neutralizer together with the bottom flow of the leached slurry for tailings neutralization. The tailings neutralization treatment time is 4 hours, and the end point pH value is 7.5. After the tailings are neutralized, solid-liquid separation is performed through thickening treatment to obtain tailings; the tailings are subjected to filter pressing treatment to obtain tailings filter cake.

[0049] The single-plate cycle of the tailings filter press treatment was 14.5 minutes, and the moisture content of the tailings filter cake obtained was 30.5%.

[0050] Example 2

[0051] The high-pressure leaching pulp of laterite nickel ore is subjected to solid-liquid separation by a 6-stage CCD to obtain the leaching pulp overflow and the leaching pulp underflow.

[0052] The leached slurry overflow is pre-neutralized to obtain a pre-neutralized slurry, wherein the pre-neutralization treatment time is 3 hours and the pH value of the pre-neutralized slurry is 2.2;

[0053] The leached slurry overflow is subjected to a first iron-aluminum removal treatment and a second iron-aluminum removal treatment to obtain an iron-aluminum removal leaching solution and iron-aluminum slag, wherein the iron-aluminum removal treatment time is 4 hours, and the pH value of the iron-aluminum removal leaching solution is 4.9;

[0054] After solid-liquid separation and washing, the iron-aluminum slag is subjected to tailings neutralization treatment together with the bottom flow of the leaching slurry and a neutralizer. The tailings neutralization treatment time is 4 hours, and the reaction end point pH value is 7.6. After the tailings are neutralized, solid-liquid separation is performed through thickening treatment to obtain tailings. The tailings are subjected to filter press treatment to obtain tailings filter cake.

[0055] The single-plate cycle of the tailings filter press treatment was 13.8 minutes, and the moisture content of the tailings filter cake obtained was 29.8%.

[0056] Comparative Example 1

[0057] The high-pressure leaching slurry of laterite nickel ore was first pre-neutralized, wherein the pre-neutralization time was 3 hours, the pH value of the pre-neutralized slurry was 2.2, and then 6-level CCD was performed to obtain the leaching slurry overflow and the leaching slurry underflow.

[0058] The overflow of the leached slurry is subjected to a first iron-aluminum removal treatment and a second iron-aluminum removal treatment to obtain an iron-aluminum removal leaching solution and iron-aluminum slag, wherein the iron-aluminum removal reaction treatment time is 4 hours, and the pH value of the iron-aluminum removal leaching solution is 4.9;

[0059] After solid-liquid separation and washing, the iron-aluminum slag is subjected to tailings neutralization treatment together with the bottom flow of the leached slurry and a neutralizer. The tailings neutralization treatment time is 4 hours, and the reaction end point pH value is 7.6. After the tailings are neutralized, solid-liquid separation is performed through thickening treatment to obtain tailings. The tailings are subjected to filter press treatment to obtain tailings filter cake.

[0060] The single-plate cycle of the tailings filter press treatment was 17.6 minutes, and the moisture content of the tailings filter cake obtained was 34.8%.

[0061] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. "First feature" and "second feature" may include one or more of the features.

[0062] In the description of the present application, "A and / or B" may include the case of A alone, the case of B alone, or any of the cases of A and B, where A and B are only used for examples and may be any technical feature connected by "and / or" in the present application.

[0063] In the present application, the writing order of each step does not mean a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of each step should be determined by its function and possible internal logic. If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) can be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0064] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, within the scope of the subject matter of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for treating high pressure leaching pulp, characterized in that: include: The high pressure leaching slurry is subjected to continuous countercurrent washing treatment to obtain a leaching slurry overflow; Pre-neutralizing the leached slurry overflow with a neutralizing agent to obtain a pre-neutralized slurry; The pre-neutralized slurry is subjected to an iron and aluminum removal treatment to obtain an iron and aluminum slag and an iron and aluminum removal leaching solution.

2. The method according to claim 1, characterized in that The pH value of the pre-neutralized slurry is 1.0-3.0; and / or, The number of stages of the continuous countercurrent washing treatment is 3 to 8.

3. The method according to claim 1, characterized in that The neutralizing agent includes at least one of quicklime, calcium carbonate and calcium hydroxide.

4. The method according to claim 1, characterized in that: After the leaching slurry overflow is subjected to the pre-neutralization treatment, the method further comprises: thickening 50%-95% by mass of the pre-neutralized slurry to obtain a pre-neutralization underflow and a pre-neutralization overflow.

5. The method according to claim 4, characterized in that Further including: Mixing the pre-neutralization underflow with the leached slurry overflow; The pre-neutralization overflow is subjected to the iron and aluminum removal treatment.

6. The method according to any one of claims 1 to 5, characterized in that: Further including: The neutralizing agent and the iron-aluminum slag are subjected to tailings neutralization treatment to obtain tailings neutralization overflow and tailings.

7. The method according to claim 6, characterized in that Further including: The tailings are subjected to filter press treatment.

8. The method according to claim 6, characterized in that The pH value of the tailings neutralization and overflow is 6.0-9.

0.

9. The method according to any one of claims 1 to 5, characterized in that: The pH value of the iron and aluminum removal leaching solution is 3.0-5.

0.

10. The method according to any one of claims 1 to 5, characterized in that: Further including: The iron-removal aluminum leaching solution is subjected to nickel-cobalt precipitation treatment to obtain a nickel-cobalt product.

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