A method for extracting nickel, cobalt, manganese and chromium from laterite nickel ore

Abstract

A method for extracting nickel, cobalt, manganese and chromium from laterite nickel ore, comprising the following steps: high-pressure acid leaching of the laterite nickel ore to obtain a leaching solution; neutralizing the leaching solution, and after solid-liquid separation, obtaining an iron and aluminum residue and an iron and aluminum removal solution; adsorbing the iron and aluminum removal solution by using a resin selective to hexavalent chromium to obtain a chromium removal solution and an adsorbed resin, the adsorbed resin containing chromium ions; desorbing the ions in the adsorbed resin by using a desorption solution to obtain an enrichment solution containing chromium ions; and extracting the chromium removal solution to obtain an extraction solution and a nickel, cobalt and manganese raffinate, the extraction solution containing impurity metal ions.

Description

Technical Field

[0001] This invention belongs to the field of laterite nickel ore processing technology, and particularly relates to a method for extracting nickel, cobalt, manganese and chromium from laterite nickel ore. Background Technology

[0002] The preparation of nickel cobalt hydroxide from laterite nickel ore typically employs a high-pressure acid leaching process. This process generates impurities such as hexavalent chromium, which negatively impacts the performance of the nickel cobalt hydroxide product. Furthermore, the wastewater and residue produced during the high-pressure acid leaching process also carry hexavalent chromium, potentially causing heavy metal pollution to the environment.

[0003] Existing methods for removing chromium typically involve adding a reducing agent to the high-pressure leaching section to inhibit chromium removal during the leaching process. 6+ The generation of hexavalent chromium. For example, patent CN 113481365 A provides a method for reducing hexavalent chromium in a high-pressure acid leaching process of laterite nickel ore. In the preparation stage and / or during the high-pressure acid leaching process, a reducing agent is added to the system to reduce hexavalent chromium during the high-pressure acid leaching process. Patent CN 111498916 A discloses a method for removing hexavalent chromium in the process of preparing nickel-cobalt hydroxide from laterite nickel ore. In this method: before the high-pressure acid leaching step, the laterite nickel ore slurry is preheated, and before the preheating step, a first reducing agent is added to the laterite nickel ore slurry, and then the laterite nickel ore slurry with the added first reducing agent enters the high-pressure acid leaching step; or, a second reducing agent is added to the leachate obtained from the circulating leaching step, and then it enters the residual ore neutralization step.

[0004] The aforementioned techniques all involve adding a reducing agent in the high-pressure leaching stage, which inhibits the hydrolytic removal of Fe during the leaching process. Therefore, it is necessary to provide a method for co-processing laterite nickel ore without adding a reducing agent, and to directly prepare nickel-cobalt-manganese ternary precursors. Summary of the Invention

[0005] To address the problems existing in current hydrometallurgical technology for laterite nickel ore, the present invention aims to provide a method for extracting nickel, cobalt, manganese, and chromium from laterite nickel ore. This method eliminates the need for reducing agents, enabling the direct separation and extraction of metallic chromium and nickel, cobalt, and manganese from a complex leachate.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for extracting nickel, cobalt, manganese, and chromium from laterite nickel ore, comprising the following steps:

[0008] (1) High-pressure acid leaching of laterite nickel ore to obtain leachate;

[0009] (2) The leachate is neutralized and the solid-liquid separation is performed to obtain iron-aluminum slag and liquid after iron and aluminum removal;

[0010] (3) The liquid after iron and aluminum removal was adsorbed by hexavalent chromium adsorption resin to obtain the liquid after chromium removal and the resin after adsorption. The resin after adsorption contains chromium ions.

[0011] (4) The chromium ions in the resin after adsorption are desorbed by the desorption solution to obtain a chromium ion enrichment solution; the chromium-removed solution is extracted to obtain an extract solution and a nickel-cobalt-manganese raffinate solution. The extract solution contains impurity metal ions.

[0012] Preferably, in step (2), the pH of the neutralization reaction is 4 to 5, and the time is 1 to 4 hours.

[0013] Preferably, the resin in step (3) is a p-Cr resin containing sulfonic acid groups or carboxyl groups. 6+ Cation exchange resins with selective adsorption.

[0014] Preferably, the desorption solution in step (4) is a dilute acid. More preferably, it is sulfuric acid.

[0015] Preferably, the impurity metal ions in step (4) include Zn 2+ Ca 2+ Mg 2+ .

[0016] Preferably, the extractant used to extract the chromium-removed liquid in step (4) is P204 or P507, the volume ratio of organic phase to aqueous phase during extraction is 1 to (5:1), the pH is 3 to 5, and the extraction time is 1 to 10 min.

[0017] Preferably, the above method further includes electrochemical reduction deposition of chromium-containing enrichment solution to obtain elemental chromium.

[0018] Preferably, the current density for electrochemical reduction deposition is 100-500 A / m. 2 The electrolysis time is 1-5 hours and the electrolysis temperature is 40-50℃.

[0019] Preferably, the above method further includes adjusting the molar ratio of nickel, cobalt, and manganese ions in the nickel-cobalt-manganese raffinate and performing a nickel-cobalt-manganese precipitation operation to obtain a nickel-cobalt-manganese ternary precursor.

[0020] Preferably, the nickel-cobalt-manganese precipitation process includes: reacting the nickel-cobalt-manganese raffinate, after adjusting the molar ratio, with a precipitant to obtain a nickel-cobalt-manganese ternary precursor. The precipitant is an alkaline solution, preferably ammonia or sodium hydroxide.

[0021] The beneficial effects of this invention are:

[0022] This invention provides a method for extracting nickel, cobalt, manganese, and chromium from laterite nickel ore. The method utilizes a chromium ion adsorption resin to sequentially adsorb, desorb, and electrodeposit hexavalent chromium in the leachate, separating and extracting metallic chromium. Furthermore, it extracts and separates impurity ions from the chromium-removed solution, obtaining a pure solution containing only nickel, cobalt, and manganese ions. This invention achieves effective separation and recovery of chromium from the leachate without the need for a reducing agent in the high-pressure acid leaching stage, producing high-purity elemental chromium. Moreover, further extraction of the chromium-removed solution yields a pure nickel-cobalt-manganese solution for the preparation of nickel-cobalt-manganese products. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below.

[0024] Figure 1 This is a flowchart of the extraction method of nickel, cobalt, manganese and chromium from laterite nickel ore according to the present invention. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] During the high-temperature and high-pressure acid leaching process of laterite nickel ore, chromium minerals in the ore are oxidized to hexavalent chromium by the action of high-valent manganese minerals such as manganese dioxide. Current technologies typically add reducing agents such as coal and sodium metabisulfite to the high-pressure acid leaching section to remove hexavalent chromium. However, adding reducing agents inhibits the removal of iron from the leachate during the recovery of nickel, cobalt, and manganese products.

[0027] To address this problem, embodiments of the present invention provide a method for extracting nickel, cobalt, manganese, and chromium from laterite nickel ore. Please refer to [link to relevant documentation]. Figure 1 This includes the following steps:

[0028] (1) High-pressure acid leaching of laterite nickel ore, wherein the leaching temperature is 180-270℃, the leaching time is 1-3h, the acid-ore ratio is controlled at 0.2-0.5kg / t, and no reducing agents such as sodium metabisulfite, sodium sulfite, or coal are added during the leaching process. After leaching, the leaching solution and leaching residue are obtained by filtration. The leaching residue can be directly landfilled or used for brick making.

[0029] (2) The leachate is neutralized with an alkaline compound at a pH of 4 to 5 for 1 to 4 hours. After solid-liquid separation, iron-aluminum slag and liquid after iron and aluminum removal are obtained.

[0030] (3) Use Cr containing sulfonic acid groups or carboxyl groups. 6+A cation exchange resin with selective adsorption is used to adsorb iron and aluminum after the liquid is removed, resulting in a chromium-removed liquid and an adsorbed resin. The adsorbed resin contains chromium ions.

[0031] (4) Dilute acid was used as the desorption solution to desorb chromium ions from the adsorbed resin, resulting in a chromium-rich solution. The chromium-rich solution was then subjected to electrochemical reduction deposition to obtain elemental chromium. The current density for electrochemical reduction deposition was 100-500 A / m. 2 The electrolysis time is 1-5 hours, and the electrolysis temperature is 40-50℃.

[0032] (5) Extract the chromium-removed solution using P204 or P507 as the extractant. The volume ratio of the organic phase to the aqueous phase during extraction is 1–(5:1), the pH is 3–5, and the extraction time is 1–10 min. This yields the extracted solution and the nickel-cobalt-manganese raffinate. The extracted solution contains Zn. 2+ Ca 2+ Mg 2+ Impurity metal ions;

[0033] The molar ratio of nickel, cobalt, and manganese ions in the nickel-cobalt-manganese raffinate is adjusted using analytically pure nickel sulfate, cobalt sulfate, and manganese sulfate. This ratio can be any one of 1:1:1, 5:2:3, 6:2:2, or 8:1:1. The raffinate with the adjusted molar ratio is then reacted with a precipitant to obtain the nickel-cobalt-manganese ternary precursor. The precipitant is an alkaline solution, preferably ammonia and / or sodium hydroxide.

[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below.

[0035] The main components of the laterite nickel ore used in the following examples include: Ni 1.67%, Co 0.08%, Mn 0.67%, Fe 37.11%, Al 3.83%, Cr 0.939%, Ca 0.13%, Mg 1.43%, and Zn 0.2-0.3%.

[0036] Chromium ion adsorption resin is prepared by Xi'an Lanxiao Technology New Materials Co., Ltd., and contains sulfonic acid groups and is effective against chromium ions. 6+ Cation exchange resins with selective adsorption.

[0037] Example 1

[0038] A method for extracting nickel, cobalt, manganese, and chromium from laterite nickel ore, comprising the following steps:

[0039] (1) Mix laterite nickel ore, water and sulfuric acid with a concentration of 98%, and carry out high-pressure acid leaching in an autoclave. The mass ratio of sulfuric acid to laterite nickel ore is 0.35 kg / t. The temperature in the autoclave is 250℃, the pressure is 4 MPa, and the leaching time is 1 h. After leaching, filter to obtain leaching solution and leaching residue. The Ni content in the leaching residue is less than 0.05%, and the pH of the leaching solution is 0.53.

[0040] (2) Add dilute sodium hydroxide solution to the leachate to adjust the pH to 4.5. After reacting for 2 hours, filter to obtain the liquid after removing iron and aluminum. The residual iron and aluminum ion concentrations are all below 5 ppm.

[0041] (3) The liquid after removing iron and aluminum is mixed with Cr 6+ The resin was contacted with an adsorption agent at a flow rate of 1.5 BV / h. After adsorption, the resin and the chromium-removed solution were obtained. The hexavalent chromium content in the chromium-removed solution was found to be below 5 ppm. The resin was then desorbed using 5% sulfuric acid at a flow rate of 2 BV / h to obtain a chromium-enriched solution. Elemental chromium was then deposited by electrochemical reduction of the chromium-enriched solution at a current density of 300 A / m³. 2 The electrolysis time is 5 hours, the electrolysis temperature is 40℃, the anode is a lead-based alloy plate, the cathode is a stainless steel plate, the cathode chromium stripping cycle is 48 hours, and the purity of the chromium metal stripped from the cathode is 99.8%.

[0042] (4) The chromium-removed solution was extracted using P2O4 as the extractant. The extraction pH was controlled at 3.5, the O / A ratio was 2:1, and the extraction time was 5 min. This yielded the extracted solution and the nickel-cobalt-manganese raffinate. The extracted solution contained Zn. 2+ Ca 2+ Mg 2+ Impurity metal ions were detected. The content of impurity metal ions in the nickel-cobalt-manganese raffinate was less than 3 ppm. The molar ratio of nickel, cobalt, and manganese ions in the nickel-cobalt-manganese raffinate was adjusted to 5:2:3 using analytical grade nickel sulfate, cobalt sulfate, and manganese sulfate. The pH of the solution was adjusted to 11.2 using ammonia water, and the temperature was controlled at 60℃. After aging for 15 h, the 523-type nickel-cobalt-manganese ternary precursor was obtained by filtration.

[0043] Example 2

[0044] A method for extracting nickel, cobalt, manganese, and chromium from laterite nickel ore, comprising the following steps:

[0045] (1) Mix laterite nickel ore, water and sulfuric acid with a concentration of 98%, and carry out high-pressure acid leaching in an autoclave. The mass ratio of sulfuric acid to laterite nickel ore is 0.35 kg / t. The temperature in the autoclave is 250℃, the pressure is 4 MPa, and the leaching time is 1 h. After leaching, filter to obtain leaching solution and leaching residue. The Ni content in the leaching residue is less than 0.05%, and the pH of the leaching solution is 0.53.

[0046] (2) Add dilute sodium hydroxide solution to the leachate to adjust the pH to 5. After reacting for 1 hour, filter to obtain the liquid after removing iron and aluminum. The residual iron and aluminum ion concentrations are all below 5 ppm.

[0047] (3) The liquid after removing iron and aluminum is mixed with Cr 6+ The resin was contacted with an adsorption agent at a flow rate of 1 BV / h. After adsorption, the resin and the chromium-removed solution were obtained. The hexavalent chromium content in the chromium-removed solution was found to be less than 5 ppm. The resin was then desorbed using 5% sulfuric acid at a flow rate of 2 BV / h to obtain a chromium-enriched solution. Elemental chromium was then deposited by electrochemical reduction of the chromium-enriched solution at a current density of 500 A / m³. 2 The electrolysis time is 1 hour, the electrolysis temperature is 50℃, the anode is a lead-based alloy plate, the cathode is a stainless steel plate, the cathode chromium stripping cycle is 48 hours, and the purity of the chromium metal stripped from the cathode is 99.6%.

[0048] (4) The chromium-removed solution was extracted using P2O4 as the extractant. The extraction pH was controlled at 5, the O / A ratio was 1:1, and the extraction time was 10 min. This yielded the extracted solution and the nickel-cobalt-manganese raffinate. The extracted solution contained Zn. 2+ Ca 2+ Mg 2+ Impurity metal ions were detected; the content of impurity metal ions in the nickel-cobalt-manganese raffinate was found to be less than 3 ppm. The molar ratio of nickel, cobalt, and manganese ions in the nickel-cobalt-manganese raffinate was adjusted to 6:2:2 using analytical grade nickel sulfate, cobalt sulfate, and manganese sulfate. The pH of the solution was adjusted to 11.5 using ammonia water, and the temperature was controlled at 50℃. After aging for 20 h, the nickel-cobalt-manganese ternary precursor was obtained by filtration.

[0049] Example 3

[0050] A method for extracting nickel, cobalt, manganese, and chromium from laterite nickel ore, comprising the following steps:

[0051] (1) Mix laterite nickel ore, water and sulfuric acid with a concentration of 98%, and carry out high-pressure acid leaching in an autoclave. The mass ratio of sulfuric acid to laterite nickel ore is 0.35 kg / t. The temperature in the autoclave is 250℃, the pressure is 4 MPa, and the leaching time is 1 h. After leaching, filter to obtain leaching solution and leaching residue. The Ni content in the leaching residue is less than 0.05%, and the pH of the leaching solution is 0.53.

[0052] (2) Add dilute sodium hydroxide solution to the leachate to adjust the pH to 4. After reacting for 4 hours, filter to obtain the liquid after removing iron and aluminum. The residual iron and aluminum ion concentrations are all below 5 ppm.

[0053] (3) The liquid after removing iron and aluminum is mixed with Cr 6+The resin was contacted with an adsorption agent at a flow rate of 3 BV / h. After adsorption, the resin and the chromium-removed solution were obtained. The hexavalent chromium content in the chromium-removed solution was found to be below 5 ppm. The resin was then desorbed using 5% sulfuric acid at a flow rate of 3 BV / h to obtain a chromium-enriched solution. Elemental chromium was then deposited by electrochemical reduction of the chromium-enriched solution at a current density of 100 A / m³. 2 The electrolysis time is 5 hours, the electrolysis temperature is 40℃, the anode is a lead-based alloy plate, the cathode is a stainless steel plate, the cathode chromium stripping cycle is 48 hours, and the purity of the chromium metal stripped from the cathode is 99.7%.

[0054] (4) The chromium-removed solution was extracted using P2O4 as the extractant. The extraction pH was controlled at 1, the O / A ratio was 5:1, and the extraction time was 1 min. This yielded the extracted solution and the nickel-cobalt-manganese raffinate. The extracted solution contained Zn. 2+ Ca 2+ Mg 2+ Impurity metal ions were detected; the content of impurity metal ions in the nickel-cobalt-manganese raffinate was found to be less than 3 ppm. The molar ratio of nickel, cobalt, and manganese ions in the nickel-cobalt-manganese raffinate was adjusted to 8:1:1 using analytical grade nickel sulfate, cobalt sulfate, and manganese sulfate. The pH of the solution was adjusted to 11.0 using ammonia water, and the temperature was controlled at 70℃. After aging for 10 h, the nickel-cobalt-manganese ternary precursor was obtained by filtration.

[0055] This invention utilizes electrodeposition to recover chromium, avoiding the extensive use of reducing agents and obtaining metallic chromium in its elemental form, thus increasing the added value of the entire process. The extraction process of this invention directly prepares nickel-cobalt-manganese ternary precursors, avoiding subsequent steps such as nickel-cobalt hydroxide (MHP) back-dissolution, extraction, and crystallization, shortening the process flow and reducing production costs. The entire process significantly reduces the emission of waste gas, wastewater, and solid waste, has low requirements for equipment and operation, and is suitable for industrial production.

[0056] It should be noted that all the above embodiments belong to the same inventive concept, and the descriptions of each embodiment have different focuses. Where the description in a particular embodiment is not detailed, please refer to the description in other embodiments.

[0057] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for extracting nickel, cobalt, manganese, and chromium from laterite nickel ore, characterized in that, Includes the following steps: (1) High-pressure acid leaching of laterite nickel ore to obtain leachate; (2) The leachate is neutralized and separated into solid and liquid to obtain iron-aluminum slag and liquid after iron and aluminum removal; (3) The iron and aluminum removal liquid is adsorbed by hexavalent chromium adsorption resin to obtain chromium removal liquid and adsorption resin; (4) The ions in the adsorbed resin are desorbed using a desorption solution to obtain a chromium-containing enriched solution; the chromium-removed solution is extracted to obtain an extracted solution and a nickel-cobalt-manganese raffinate, wherein the extracted solution contains impurity metal ions. The resin mentioned in step (3) is a p-Cr resin containing sulfonic acid groups or carboxyl groups. 6+ Cation exchange resins with selective adsorption capabilities; The desorption solution in step (4) is a dilute acid; The extractant used in step (4) is P204 or P507. The volume ratio of organic phase to aqueous phase during the extraction process is 1 to (5:1), the pH is 3 to 5, and the extraction time is 1 to 10 min.

2. The method for extracting nickel, cobalt, manganese, and chromium from laterite nickel ore according to claim 1, characterized in that, The neutralization in step (2) is performed at a pH of 4 to 5 for 1 to 4 hours.

3. The method for extracting nickel, cobalt, manganese, and chromium from laterite nickel ore according to claim 1, characterized in that, The impurity metal ions in step (4) include Zn 2+ Ca 2+ Mg 2+ .

4. The method for extracting nickel, cobalt, manganese, and chromium from laterite nickel ore according to claim 1, characterized in that, It also includes electrochemical reduction deposition of the chromium-containing enrichment solution to obtain elemental chromium.

5. The method for extracting nickel, cobalt, manganese, and chromium from laterite nickel ore according to claim 4, characterized in that, The current density of the electrochemical reduction deposition is 100-500 A / m. 2 The electrolysis time is 1-5 hours and the electrolysis temperature is 40-50℃.

6. The method for extracting nickel, cobalt, manganese, and chromium from laterite nickel ore according to claim 1, characterized in that, It also includes adjusting the molar ratio of nickel, cobalt, and manganese ions in the nickel-cobalt-manganese raffinate and performing a nickel-cobalt-manganese precipitation operation to obtain a nickel-cobalt-manganese ternary precursor.

7. The method for extracting nickel, cobalt, manganese, and chromium from laterite nickel ore according to claim 6, characterized in that, The nickel-cobalt-manganese precipitation process includes: reacting the nickel-cobalt-manganese raffinate with a precipitant to obtain a nickel-cobalt-manganese ternary precursor, wherein the precipitant is an alkaline solution.

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