WO2024130854A1

WO2024130854A1 - Isolation reagent and resource utilization method for magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon

Info

Publication number: WO2024130854A1
Application number: PCT/CN2023/080228
Authority: WO
Inventors: 张荣荣; 彭小聪; 伍永国; 刘勇奇; 巩勤学; 李长东
Original assignee: 广东邦普循环科技有限公司; 湖南邦普循环科技有限公司
Priority date: 2022-12-21
Filing date: 2023-03-08
Publication date: 2024-06-27
Also published as: CN115927849A; FR3144170A1

Abstract

The present invention relates to the technical field of hydrometallurgy. Disclosed are an isolation reagent and a resource utilization method for a magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon. The isolation reagent comprises an extraction agent and a synergistic extraction agent, the extraction agent comprises BC196, and the synergistic extraction agent comprises Mextral 6103H. By using BC196 in conjunction with Mextral 6103H and reducing the pH value of an aqueous phase solution, the isolation reagent can be adapted to an iron-containing solution, and the load capacity and the isolation coefficient are improved, thus effectively isolating cobalt from iron, zinc, calcium, silicon and magnesium. The resource utilization method for the magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon comprises using the isolation reagent to extract the magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon, and the recovery rate of cobalt can reach 99%. In the method, no dangerous chemicals are introduced and no hazardous waste is generated, so that the extraction efficiency is high and the isolation coefficient is high; the process flow is short, and device investment is low.

Description

Separation reagent and resource utilization method of magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon

Technical Field

The invention relates to the technical field of hydrometallurgy, and in particular to a separation reagent and a method for resource utilization of a magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon.

Background technique

With the rapid development of new energy technologies, 5G and other related electronic technologies, the demand for batteries will increase in the future. As the most important elements in battery components, the demand for nickel, cobalt, manganese, lithium and magnesium will continue to increase. Therefore, some low-grade nickel-cobalt ores, salt lakes, nickel-cobalt intermediates, etc. that were previously rarely mined or not mined will gradually be mined, improving the resource level of low-grade mines and salt lakes. Obtaining high-purity nickel, cobalt, manganese, lithium and magnesium products will greatly reduce mining costs, improve competitiveness, and occupy market share.

In the prior art, some methods extract nickel-cobalt bioleaching solution by using a reagent containing Versatic10. However, Versatic10 has a large solubility in water. After multiple extractions, the dissolution loss of Versatic10 causes a large change in the composition of the combined extractant, and the extraction performance changes greatly, making it impossible to apply it to large-scale production.

Some methods use fluoride to remove calcium and magnesium, but this method is too expensive in industrial production, and the cost of introducing fluoride ion environment treatment is also high.

Some extract all the magnesium directly with P204. Since the separation coefficient of nickel, cobalt and magnesium is very low, when P204 is used to extract all the magnesium, on the one hand, the amount of extractant used is large, and on the other hand, part of the nickel and cobalt will enter the extraction. The treatment process for the extracted magnesium, part of the nickel and cobalt is to add liquid alkali for flocculation and precipitation, treat the wastewater, and recover magnesium while recovering nickel and cobalt through precipitation. When the recovered material is returned to production for reuse, a small amount of magnesium is continuously enriched, which will eventually affect the extraction efficiency, increase the amount of extractant used, and increase production costs.

Others use sodium sulfide to precipitate wastewater, recover nickel, cobalt and manganese metals, and precipitate magnesium. Although this method can meet the wastewater standards (nickel and cobalt ≤ 0.5ppm), the addition of sodium sulfide will produce hydrogen sulfide, which is extremely dangerous and has poor controllability. In addition, the wastewater is yellowish and does not meet environmental protection requirements.

That is, the existing technical solutions have the problems of environmental risks in using sodium sulfide, long process flow, low metal recovery rate, high water solubility of the extractant, and low loading capacity.

In view of this, the present invention is proposed.

Summary of the invention

One of the purposes of the present invention is to provide a separation reagent for separating cobalt from iron, zinc, calcium, silicon and magnesium, which has low water solubility and is easy to separate. The coefficient is large and the organic loss is small, which can effectively separate cobalt from iron, zinc, calcium, silicon and magnesium.

The second object of the present invention is to provide an application of the above separation reagent in separating cobalt and iron, zinc, calcium, silicon and magnesium.

The third object of the present invention is to provide a method for resource utilization of magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon, which has a short process, low cost, high metal recovery rate and good solution quality.

This application can be implemented as follows:

In a first aspect, the present application provides a separation reagent for separating cobalt from iron, zinc, calcium, silicon and magnesium, which comprises an extractant and a synergist;

The extractant includes BC196, and the co-extractant includes Mextral 6103H.

In an optional embodiment, the volume percentage of BC196 in the separation reagent is 5-15%, and/or the volume percentage of Mextral 6103H in the separation reagent is 5-8%.

In an optional embodiment, the separation reagent further includes a diluent; the volume percentage of the diluent in the separation reagent is the remainder after removing the extractant and the synergistic extractant.

In an alternative embodiment, the diluent comprises at least one of kerosene, sulphonated kerosene, Escaid 110, heptane, hexane, dodecane and sec-octanol.

In a second aspect, the present application provides the use of a separation reagent as described in any of the aforementioned embodiments in separating cobalt and iron, zinc, calcium, silicon and magnesium.

In a third aspect, the present application provides a method for resource utilization of a magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon, comprising the following steps:

The magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon is extracted using a separation reagent as described in any of the aforementioned embodiments to obtain a loaded organic phase and a raffinate water phase.

In an optional embodiment, the volume ratio of the separation reagent to the magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon is 1:0.5-1:20.

In an optional embodiment, the extraction method includes single-stage extraction or multi-stage countercurrent extraction.

In an alternative embodiment, the pH value of the raffinate aqueous phase is 4.5-5.

In an optional embodiment, the separation reagent is further subjected to saponification treatment before extraction.

In an optional embodiment, the saponifying agent used in the saponification treatment is an alkaline solution.

In an optional embodiment, the alkaline solution includes at least one of sodium hydroxide solution, ammonia water, potassium hydroxide solution and magnesium hydroxide solution.

In an optional embodiment, the concentration of the alkaline solution is 5-10 mol/L.

In an optional embodiment, the saponification degree after saponification is greater than 0 and not more than 50%.

In an optional embodiment, the method further comprises: stripping the loaded organic phase with a stripping agent to obtain a battery-grade cobalt sulfate solution.

In an optional embodiment, the stripping agent includes at least one of a sulfuric acid solution and a hydrochloric acid solution.

In an optional embodiment, the H ⁺ concentration in the stripping agent is 3-5 mol/L.

In an optional embodiment, the number of stripping treatment stages is 1-5.

In an optional embodiment, before the stripping, the loaded organic phase is further washed with a washing liquid.

In an optional embodiment, the washing liquid used in the washing treatment includes at least one of water, sulfuric acid solution, hydrochloric acid solution, phosphoric acid solution and oxalic acid solution.

In an alternative embodiment, the H ⁺ concentration of the washing solution does not exceed 1 mol/L.

In an optional embodiment, the volume ratio of the washing liquid to the loaded organic phase is 0.05:1-0.5:1.

In an optional embodiment, the washing treatment method is multi-stage countercurrent washing.

In an optional embodiment, the volume ratio of the stripping agent to the washed loaded organic phase is 0.05:1-0.5:1.

In an optional embodiment, the method further comprises: performing ion adsorption on the raffinate water phase to obtain a refined magnesium sulfate solution.

In an optional embodiment, the ion exchange resin used for ion adsorption is a sodium type resin.

In an optional embodiment, the sodium type resin includes at least one of D467, Seplite D001, LSC850 and D503.

The beneficial effects of this application include:

The present application creatively uses BC196 and Mextral 6103H reagents together to extract cobalt, effectively solving the problem that BC196 is not suitable for iron-containing solutions and has a high equilibrium pH, and Mextral 6103H has a low load and a low separation coefficient, and can achieve effective separation of cobalt from iron, zinc, calcium, silicon and magnesium. In addition, BC196 and Mextral 6103H have a large separation coefficient for cobalt and impurities such as magnesium, iron, zinc, calcium and silicon, low water solubility and low organic loss.

The above separation reagent is used to extract the magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon, and the cobalt recovery rate can reach 99%. This method does not introduce any hazardous chemicals, does not generate any hazardous waste, has high extraction efficiency, large separation coefficient, short process flow and low equipment investment.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

FIG1 is a flow chart of the method for resource utilization of magnesium sulfate solution in Example 1 of the present application.

Detailed ways

In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

The separation reagent provided in this application and the resource utilization method of the magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon are specifically described below.

The present application proposes a separation reagent for separating cobalt and iron, zinc, calcium, silicon and magnesium, which comprises an extractant and a synergist.

The above-mentioned extractants include BC196, and the co-extractants include Mextral 6103H.

That is, the separation reagent provided in the present application comprises BC196 and Mextral 6103H as components. In addition, other extractants and co-extractants may be added to BC196 and Mextral 6103H as needed.

The above-mentioned BC196 is an acid compound, a colorless or light yellow liquid, with a density of 0.85-0.88 g/mL and a purity of ≥90%, which can be purchased from Suzhou Bocui Circulation Technology Co., Ltd. Mextral 6103H is a lipid extractant, a brown transparent liquid, with a density of 0.97±0.005 g/mL and a flash point of ＞70°C, which can be purchased from Comp Chemical Co., Ltd.

For reference, the volume percentage of BC196 in the separation reagent can be 5-15%, such as 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%, etc., or it can be any other value within the range of 5-15%.

The volume percentage of Mextral 6103H in the separation reagent can be 5-8%, such as 5%, 5.5%, 6%, 6.5%, 7%, 7.5% or 8%, etc., or any other value within the range of 5-8%.

Furthermore, the above separation reagent also includes a diluent, and the volume percentage of the diluent in the separation reagent is the remainder after removing the extractant and the synergistic extractant.

Exemplarily, the diluent may include at least one of kerosene, sulfonated kerosene, Escaid 110, heptane, hexane, dodecane and secondary octanol.

In some preferred embodiments, the separation reagent is composed of an extractant, a synergist and a diluent, wherein the extractant is BC196 and the synergist is Mextral 6103H. By volume percentage, BC196 accounts for 5-15% of the separation reagent, Mextral 6103H accounts for 5-8% of the separation reagent, and the remainder is the diluent.

It should be noted that BC196 usually has a high equilibrium pH when extracting cobalt and is not suitable for iron-containing systems. It also has high water solubility and large organic losses, which bring environmental problems. Mextral 6103H has a small load and a poor separation coefficient between cobalt and iron and silicon. The inventor creatively used BC196 and Mextral 6103H together to extract cobalt, effectively solving the problems that BC196 is not suitable for iron-containing solutions and has a high equilibrium pH and Mextral 6103H has a small load and a low separation coefficient, and can achieve effective separation of cobalt from iron, zinc, calcium, silicon and magnesium. In addition, BC196 and Mextral 6103H have a large separation coefficient for cobalt and impurities such as magnesium, iron, zinc, calcium and silicon, low water solubility and low organic losses.

Accordingly, the present application also provides the application of the above separation reagent, which can be used, for example, in the separation of cobalt and iron, zinc, calcium, silicon and magnesium. Specifically, the above separation reagent can be used to extract the substance containing cobalt and iron, zinc, calcium, silicon and magnesium to be separated.

In addition, the present application also provides a method for resource utilization of magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon, comprising the following steps:

The above separation reagent is used to extract the magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon to obtain a loaded organic phase and a raffinate water phase.

In some embodiments, the magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon is a stripping solution produced by leaching battery waste or nickel-cobalt intermediates, removing iron, aluminum and copper, and then extracting and removing impurities with P507. In the magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon, the magnesium concentration is 25-45g/L, the calcium concentration is 0.05-0.15g/L, the zinc concentration is 0.01-0.5g/L, the cobalt concentration is 0.2-5g/L, the silicon concentration is 0.01-0.1g/L, the sodium concentration is 0.02-0.05g/L, and the iron concentration is 0.05-0.1g/L.

For reference, the volume ratio of the separation agent to the magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon can be 1:0.5-1:20, such as 1:0.5, 1:1, 1:2, 1:5, 1:8, 1:10, 1:12, 1:15, 1:18 or 1:20, or any other value within the range of 1:0.5-1:20.

The extraction method can be single-stage extraction or multi-stage (number of stages ≥ 2) countercurrent extraction.

After extraction, the pH value of the raffinate aqueous phase is about 4.5-5.

In some preferred embodiments, before extraction, the separation reagent is further subjected to saponification treatment.

For reference, the saponifying agent used in the saponification treatment is an alkaline solution, for example, may include at least one of a sodium hydroxide solution, an ammonia solution, a potassium hydroxide solution and a magnesium hydroxide solution.

The concentration of the alkaline solution can be 5-10mol/L, such as 5mol/L, 5.5mol/L, 6mol/L, 6.5mol/L, 7mol/L, 7.5mol/L, 8mol/L, 8.5mol/L, 9mol/L, 9.5mol/L or 10mol/L, etc., or it can be any other value within the range of 5-10mol/L.

Preferably, the saponification degree after saponification treatment is greater than 0 and not more than 50%, such as 0.5%, 1%, 2%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50%, etc., and can also be any other value within the range of greater than 0 and not more than 50%.

Furthermore, a stripping agent is used to strip the loaded organic phase obtained after the above extraction to obtain a battery-grade cobalt sulfate solution. The battery-grade cobalt sulfate solution can be directly used for ternary precursor synthesis.

For reference, the stripping agent may include at least one of a sulfuric acid solution and a hydrochloric acid solution.

The H ⁺ concentration in the stripping agent can be 3-5 mol/L, such as 3 mol/L, 3.5 mol/L, 4 mol/L, 4.5 mol/L or 5 mol/L, or any other value within the range of 3-5 mol/L.

The number of stages of the stripping treatment may be, for example, 1-5 stages, specifically, 1, 2, 3, 4 or 5 stages.

In some preferred embodiments, before stripping, the loaded organic phase is further washed with a washing liquid.

For reference, the washing liquid used in the washing treatment may include, for example, at least one of water, a sulfuric acid solution, a hydrochloric acid solution, a phosphoric acid solution, and an oxalic acid solution.

The H+ concentration of the washing solution does not exceed 1mol/L, such as 0mol/L, 0.1mol/L, 0.2mol/L, 0.3mol/L, 0.4mol/L, 0.5mol/L, 0.6mol/L, 0.7mol/L, 0.8mol/L, 0.9mol/L or 1mol/L, etc., and can also be any other value not exceeding 1mol/L.

The volume ratio of the washing liquid to the loaded organic phase can be 0.05:1-0.5:1, such as 0.05:1, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1 or 0.5:1, or any other value within the range of 0.05:1-0.5:1.

The washing treatment method is preferably multi-stage countercurrent washing.

The volume ratio of the stripping agent to the washed loaded organic phase may be 0.05:1-0.5:1, such as 0.05:1, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1 or 0.5:1, or any other value within the range of 0.05:1-0.5:1.

Further, the raffinate water phase is subjected to ion adsorption to obtain a refined magnesium sulfate solution. The pH of the refined magnesium sulfate solution after the iron, zinc, calcium and silicon are removed by ion exchange is controlled at 4.5-5.

For reference, the ion exchange resin used for the above ion adsorption is preferably a sodium type resin, for example, it may include at least one of D467, Seplite D001, LSC850 and D503.

The above resin is a light yellow and beige granular material, which can be purchased from Xi'an Lanxiao Technology Co., Ltd.

The above ion adsorption principle includes: resins such as D467 or LSC850 do not adsorb magnesium under acidic conditions, but can completely adsorb iron, zinc, calcium and silicon, achieving 99% recovery of cobalt and magnesium.

For example, the obtained battery-grade cobalt sulfate solution has a cobalt content of >100 g/L, a copper and zinc content of <0.5 ppm, a calcium and magnesium content of <3 ppm, a chromium content of <2 ppm, a silicon content of <8 ppm, a sodium content of <100 ppm, and an iron content of <1 ppm. The obtained refined magnesium sulfate solution has a magnesium content of >25 g/L, a cobalt content of <0.5 ppm, a nickel content of <0.5 ppm, a zinc content of <2 ppm, a calcium content of <1 ppm, a silicon content of <1 ppm, and an iron content of <5 ppm.

As mentioned above, the method for separating magnesium from cobalt, iron, zinc, calcium and silicon provided in the present application achieves the separation of magnesium from cobalt, iron, zinc, calcium and silicon by combining extraction and ion exchange methods, and obtains battery-grade cobalt sulfate solution and refined magnesium sulfate solution. The battery-grade cobalt sulfate solution is directly used for the synthesis of ternary precursors.

This method does not introduce any hazardous chemicals, does not generate any hazardous waste, has high extraction efficiency, large separation coefficient, short process, low cost, small equipment investment, high metal recovery rate, and good solution quality, thus achieving efficient recovery of cobalt and resource utilization of magnesium.

The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

Example 1

This embodiment provides a method for resource utilization of magnesium sulfate solution, referring to FIG. 1 , comprising the following steps:

Step (1): Prepare a separation reagent by mixing the extractant BC196, the co-extractant Mextral 6103H and the diluent (Escaid110) in a volume ratio of 5:5:90;

Step (2): using an alkaline solution (sodium hydroxide aqueous solution) with a concentration of 10 mol/L to saponify the above separation reagent, with a saponification degree of 50%, to obtain a saponified separation reagent;

Step (3): The volume ratio of the magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon (pH value is 3.0) to the saponified separation reagent is 2:1, perform 4-stage countercurrent extraction, stand for 5 minutes, and then separate the upper organic phase and the lower aqueous phase to obtain a loaded organic phase and a raffinate aqueous phase;

Step (4): using 0.5 mol/L dilute sulfuric acid at a volume ratio of 1:20 between the washing liquid and the loaded organic phase to perform four-stage countercurrent washing to obtain a washed loaded organic phase; using 2.5 mol/L sulfuric acid at a volume ratio of 1:20 between the sulfuric acid and the washed loaded organic phase to perform three-stage countercurrent stripping, cyclic enrichment, and obtain a battery-grade cobalt sulfate solution;

Step (5): The pH value of the raffinate water phase (magnesium sulfate solution containing iron, zinc, calcium and silicon) is 4.6, and it is passed through a D467 resin bed at 2 BV/h to obtain a refined magnesium sulfate solution after adsorbing iron, zinc, calcium and silicon.

Example 2

This embodiment provides a method for resource utilization of magnesium sulfate solution, comprising the following steps:

Step (1): Prepare a separation reagent by mixing the extractant BC196, the co-extractant Mextral 6103H and the diluent (Escaid110) in a volume ratio of 10:5:85;

Step (3): The volume ratio of the magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon (pH value is 3.2) to the saponified separation reagent is 4:1, and four-stage countercurrent extraction is performed. After standing for 5 minutes, the upper organic phase and the lower aqueous phase are separated to obtain a loaded organic phase and a raffinate aqueous phase;

Step (4) and step (5) are the same as in Example 1.

Example 3

Step (1) and step (2) are the same as in Example 1.

Step (3): The volume ratio of the magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon (pH 4.0) to the saponified organic phase is 2:1, and four-stage countercurrent extraction is performed. After standing for 5 minutes, the upper organic phase and the lower aqueous phase are separated to obtain a loaded organic phase;

Step (4) is the same as in Example 1.

Step (5): The pH value of the raffinate water phase (magnesium sulfate solution containing iron, zinc, calcium and silicon) is 4.7, and it is passed through a D467 resin bed at 2 BV/h to obtain a refined magnesium sulfate solution after adsorbing iron, zinc, calcium and silicon.

Example 4

Step (1): Prepare a separation reagent by mixing the extractant BC196, the co-extractant Mextral 6103H and the diluent (kerosene) in a volume ratio of 15:6:79;

Step (2): Soap the separation reagent with an alkaline solution (sodium hydroxide aqueous solution) at a concentration of 5 mol/L. The saponification degree is 5%, and the saponified separation reagent is obtained;

Step (3): a magnesium sulfate solution (pH 3.0) containing cobalt, iron, zinc, calcium and silicon and a saponified separation agent in a volume ratio of 10:1, and a single-stage extraction is performed. After standing for 5 minutes, the upper organic phase and the lower aqueous phase are separated by phase separation to obtain a loaded organic phase and a residual aqueous phase;

Step (4): using 0.5 mol/L hydrochloric acid to perform three-stage countercurrent washing under the condition that the volume ratio of the washing liquid to the loaded organic phase is 0.5:1, to obtain a washed loaded organic phase; using 3 mol/L hydrochloric acid to perform five-stage countercurrent stripping under the condition that the volume ratio of the hydrochloric acid to the washed loaded organic phase is 0.5:1, and cyclic enrichment to obtain a battery-grade cobalt sulfate solution;

Step (5): The pH value of the raffinate aqueous phase (magnesium sulfate solution containing iron, zinc, calcium and silicon) is 4.6, and it is passed through a Seplite D001 resin bed at 2 BV/h to obtain a refined magnesium sulfate solution after adsorbing iron, zinc, calcium and silicon.

Example 5

Step (1): Prepare a separation reagent by mixing the extractant BC196, the co-extractant Mextral 6103H and the diluent (octanol) in a volume ratio of 10:8:82;

Step (2): using an alkaline solution (potassium hydroxide solution) with a concentration of 7.5 mol/L to saponify the above separation reagent, with a saponification degree of 25%, to obtain a saponified separation reagent;

Step (3): The volume ratio of the magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon (pH value is 3.0) to the saponified separation reagent is 20:1, and two-stage countercurrent extraction is performed. After standing for 5 minutes, the upper organic phase and the lower aqueous phase are separated to obtain a loaded organic phase and a residual aqueous phase;

Step (4): using water to perform a second-stage countercurrent washing at a volume ratio of 0.1:1 between the washing liquid and the loaded organic phase to obtain a washed loaded organic phase; using 2 mol/L sulfuric acid to perform a first-stage stripping at a volume ratio of 0.1:1 between the sulfuric acid and the washed loaded organic phase to obtain a battery-grade cobalt sulfate solution;

Step (5): The pH value of the raffinate aqueous phase (magnesium sulfate solution containing iron, zinc, calcium and silicon) is 4.6, and it is passed through the LSC850 resin bed at 2BV/h to obtain a refined magnesium sulfate solution after adsorbing iron, zinc, calcium and silicon.

Test example

The contents of various elements in the magnesium sulfate solutions containing cobalt, iron, zinc, calcium and silicon in the above Examples 1-5 and the separated cobalt sulfate solutions and magnesium sulfate solutions were tested, and the results are shown in Table 1.

Table 1 Effects of organic content and feed pH on element extraction

It can be seen from Table 1 that the methods provided in Examples 1-5 can effectively separate magnesium from cobalt, iron, zinc, calcium and silicon.

Comparative Example 1

The difference between this comparative example and Example 1 is that the extractant BC196 is replaced by C272.

The results show that magnesium, cobalt, zinc and calcium cannot be effectively separated.

Comparative Example 2

The difference between this comparative example and Example 1 is that the separation reagent does not contain the synergist Mextral 6103H, and the amount of the original synergist Mextral 6103H is made up with the diluent.

The results show that when the requirement for cobalt in the raffinate is met, the pH is about 6.9, iron forms colloid, the organic phase and the aqueous phase are difficult to separate, and the process cannot be run.

Comparative Example 3

The difference between this comparative example and Example 1 is that no ion adsorption is performed on the raffinate water phase.

The results show that magnesium cannot be effectively separated from iron, zinc, calcium and silicon.

In summary, the present invention uses a combination of extraction and ion exchange to separate magnesium from cobalt, iron, zinc, calcium and silicon, and obtains a battery-grade cobalt sulfate solution and a refined magnesium sulfate solution. The battery-grade cobalt sulfate solution is directly used for ternary precursor synthesis, and the recovery rate of cobalt and magnesium can reach 99%. The method does not introduce hazardous chemicals, does not generate hazardous waste, has high extraction efficiency, large separation coefficient, short process, low cost, low equipment investment, high metal recovery rate, good solution quality, and realizes efficient recovery of cobalt and resource utilization of magnesium.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. Any modification, equivalent replacement, Improvements and the like should all be included in the protection scope of the present invention.

Claims

A separation reagent for separating cobalt from iron, zinc, calcium, silicon and magnesium, characterized in that the separation reagent comprises an extractant and a synergist;

The extractant includes BC196, and the synergistic extractant includes Mextral 6103H.
The separation reagent according to claim 1 is characterized in that the volume percentage of BC196 in the separation reagent is 5-15%, and/or the volume percentage of Mextral 6103H in the separation reagent is 5-8%.
The separation reagent according to claim 2, characterized in that the separation reagent further comprises a diluent; the volume percentage of the diluent in the separation reagent is the remainder after removing the extractant and the synergistic extractant;

Preferably, the diluent comprises at least one of kerosene, sulphonated kerosene, Escaid 110, heptane, hexane, dodecane and sec-octanol.
Use of the separation reagent as described in any one of claims 1 to 3 in separating cobalt and iron, zinc, calcium, silicon and magnesium.
A method for resource utilization of magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon, characterized in that it comprises the following steps:

The separation reagent according to any one of claims 1 to 3 is used to extract the magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon to obtain a loaded organic phase and a raffinate water phase;

Preferably, the volume ratio of the separation reagent to the magnesium sulfate solution containing cobalt, iron, zinc, calcium and silicon is 1:0.5-1:20;

Preferably, the extraction method includes single-stage extraction or multi-stage countercurrent extraction;

Preferably, the pH value of the raffinate aqueous phase is 4.5-5.
The method for resource utilization of magnesium sulfate solution according to claim 5, characterized in that it also includes saponifying the separation reagent before extraction;

Preferably, the saponifying agent used in the saponification treatment is an alkaline solution;

Preferably, the alkaline solution comprises at least one of sodium hydroxide solution, ammonia water, potassium hydroxide solution and magnesium hydroxide solution;

Preferably, the concentration of the alkaline solution is 5-10 mol/L;

Preferably, the saponification degree after saponification treatment is greater than 0 and not more than 50%.
The method for resource utilization of magnesium sulfate solution according to claim 5 or 6, characterized in that it also includes: stripping the loaded organic phase with a stripping agent to obtain a battery-grade cobalt sulfate solution;

Preferably, the stripping agent comprises at least one of a sulfuric acid solution and a hydrochloric acid solution;

Preferably, the H + concentration in the stripping agent is 3-5 mol/L;

Preferably, the number of stages of stripping treatment is 1-5.
The method for resource utilization of magnesium sulfate solution according to claim 7, characterized in that before stripping, it also includes washing the loaded organic phase with a washing liquid;

Preferably, the washing liquid used in the washing treatment comprises at least one of water, sulfuric acid solution, hydrochloric acid solution, phosphoric acid solution and oxalic acid solution;

Preferably, the H+ concentration of the washing solution does not exceed 1 mol/L;

Preferably, the volume ratio of the washing liquid to the loaded organic phase is 0.05:1-0.5:1;

Preferably, the washing treatment method is multi-stage countercurrent washing;

Preferably, the volume ratio of the stripping agent to the washed loaded organic phase is 0.05:1-0.5:1.
The method for resource utilization of magnesium sulfate solution according to claim 5 or 6 is characterized in that it also includes: performing ion adsorption on the raffinate water phase to obtain a refined magnesium sulfate solution.
The method for resource utilization of magnesium sulfate solution according to claim 9, characterized in that the ion exchange resin used for ion adsorption is a sodium type resin;

Preferably, the sodium type resin includes at least one of D467, Seplite D001, LSC850 and D503.