CN116770095A - A method for recovering cobalt from cobalt-containing slag - Google Patents

Abstract

The invention relates to the technical field of cobalt metal recovery, in particular to a method for recovering cobalt by utilizing cobalt-containing slag. The method comprises the steps of converter slag sample preparation, reduction roasting test research, mineral separation enrichment test research. The method improves the recovery efficiency of cobalt metal in the process of recovering cobalt from the cobalt-containing slag, reduces the cobalt metal by using a reducing agent with lower cost, and saves the cost.

Description

A method for recovering cobalt from cobalt-containing slag

Technical field

The present invention relates to the technical field of cobalt metal recovery, specifically a method for recovering cobalt by utilizing cobalt-containing slag.

Background technique

Cobalt is an extremely important basic raw material that is widely used in the production of battery materials, cemented carbide, high-temperature alloys, magnetic materials and other advanced materials. However, my country is a country with scarce cobalt resources. As of 2000, my country's proven cobalt reserves were only 471,000 tons. In order to meet industry demand, my country needs to import cobalt resources at a high cost every year. In order to alleviate this situation, the development and utilization of secondary cobalt resources is the inevitable path for my country's cobalt smelting industry. Except for a small number of independent deposits, most cobalt occurs in associated forms in copper, nickel, lead-zinc ores, and these associated cobalt resources form different types of secondary cobalt resources in the subsequent smelting process. For example, cobalt associated with lead-zinc ores enters the production system during the zinc smelting process and is enriched to form cobalt-containing solutions in different forms, such as purification liquid (containing Co: 10-30 mg/L), cadmium-depleted liquid (containing Co :50-300mg/L), high cobalt liquid (containing Co:500-2000mg/L). According to statistics, every 1 ton of zinc produced is accompanied by 0.2-0.4 kg of cobalt. Based on this calculation, domestic hydrometallurgical zinc smelting plants can produce 1,000-2,000 tons of cobalt every year, which is a considerable amount. Therefore, how to efficiently utilize this cobalt resource to alleviate the current situation of cobalt resource shortage in my country has very positive significance.

However, the utilization rate of cobalt-containing solutions produced by the zinc hydrometallurgy industry is not high. The reason for this situation is that the composition of these cobalt-containing solutions is complex, and they all contain a certain amount of zinc, manganese, and cobalt. The properties of these elements are relatively similar and are difficult to separate. Therefore, the recovery of cobalt from solutions containing manganese, zinc, and cobalt has always been a research hotspot in the industry.

Currently, extraction and oxidative precipitation methods are mainly used to extract cobalt from solutions containing zinc, manganese, and cobalt. In the cobalt extraction and recovery process, P204 and P507 are the most widely used extraction agents. However, according to the extraction characteristics, P204 and P507 preferentially extract manganese and zinc. That is to say, for solutions containing manganese, zinc, and cobalt, the current Some mainstream extraction processes are unable to achieve effective separation and efficient recovery of zinc, manganese and cobalt. The oxidation precipitation method uses an oxidizing agent to oxidize Co ²⁺ into Co ³⁺ , causing it to precipitate from the solution in the form of Co(OH) ₃ . However, due to the high redox potential of Co ²⁺ , strong oxidants are required to achieve the oxidation of Co ²⁺ , such as chlorine, potassium permanganate, and persulfate. What is particularly important is that Mn ²⁺ is more easily oxidized than Co ²⁺ , which not only results in greater oxidant consumption and a sharp increase in cost, but also causes a large amount of MnO ₂ to enter the precipitated cobalt slag, causing the cobalt slag to be of low grade and low value.

Cobalt metal in the slag is mainly found in iron silicate minerals and magnetic iron compounds, which must be reduced and dissociated at high temperatures to form a strong magnetic iron-cobalt alloy with metallic iron to achieve selective ore enrichment and recovery of cobalt. Since there is no mature comprehensive recycling technology, this part of cobalt resources has not been effectively utilized so far. In recent years, the new energy battery industry has developed rapidly and the demand for cobalt has accelerated. Therefore, it is necessary to carry out research and development of recycling technology for such cobalt resources.

Contents of the invention

In view of the problems existing in the current prior art, the purpose of the present invention is to provide a method for recovering cobalt using cobalt-containing slag. It aims to improve the cobalt metal recovery efficiency of the cobalt-containing slag recovery process and at the same time use a lower-cost reducing agent to reduce cobalt metal and save costs.

In order to solve the above technical problems, the present invention specifically provides the following technical solutions.

A method for recovering cobalt from cobalt-containing slag, including the following steps:

S1: Converter slag sample preparation;

S2: Experimental study on reduction roasting;

S3: Experimental research on mineral processing and enrichment.

Preferably, the converter slag sample preparation in step S1 is specifically:

Since the particle size of the slag sample taken is relatively large, it needs to be processed. The slag sample taken is crushed by a jaw crusher and a roller crusher until 80% passes through a sieve with a mesh size of 3.0 mm. Then mix, divide, take samples, and set aside.

Preferably, the reduction roasting test research in step S2 is specifically:

For the static reduction condition test, take 300g of slag sample each time, mix it with a certain proportion of reducing agent, mix it evenly, put it into an 800ml crucible, and then put it into a muffle furnace for static roasting. After the heating and insulation are completed, take it out and cool it naturally. After cooling completely, weigh and send to magnetic separation;

Rotary kiln dynamic verification test, take 500g slag sample each time, add reducing agent, put it into a 90mm diameter rotary kiln for dynamic roasting, take it out after completing the heating and insulation, put it into water to cool, wait until the material is completely cooled, then dry and weigh , sent to magnetic separation.

Preferably, the mineral processing and enrichment experimental research in step S3 is specifically:

Magnetic separation is carried out at a grinding fineness of -0.075mm accounting for 75% and a magnetic field strength of 95.54KA/m to obtain magnetic separation concentrate.

Preferably, the reducing agent in step S2 includes pyrite and reduced coal; the added mass of reduced coal is 8%-11% of the slag mass, and the added mass of pyrite is 40%-50% of the slag mass.

Preferably, the calcination temperature in step S2 is 1150°C-1300°C, and the reduction time is 1.5h-2.5h.

Compared with the prior art, the present invention has the following beneficial effects.

1. Using pyrometallurgy, compared with oxygen pressure leaching of hydrometallurgy, the yield of slag treated by pyrometallurgy is larger, it is easier to meet the needs of actual production, and it is economically more cost-effective than the technical process of hydrometallurgy.

2. The optimal process and technical conditions obtained from the converter slag reduction roasting test of the present invention are: the reduction roasting temperature is 1200°C, the added mass of pyrite is 40% of the slag mass, and the corresponding reduced coal added mass is 10% of the slag mass. The reduction roasting test was carried out under optimal conditions with a reduction time of 2 hours, and the technical indicators of the cobalt grade of the magnetically separated cobalt concentrate product were 5.13% and the cobalt metal recovery rate was 89.98%. The recovery rate of cobalt metal was improved, and pyrite was available. Substituting partially reduced coal as the reducing agent for converter slag reduction roasting to recover cobalt is beneficial to cost savings.

Description of drawings

Figure 1 is a process flow chart of a method for recovering cobalt from cobalt-containing slag.

Detailed ways

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

Example 1.

The sample comes from Zambia. The main components (mass percentage): Co 1.54%, Fe 45.91%, Cu 6.26%, SiO ₂ 24.69%, CaO 0.217%, MgO 0.282%, S 0.410%.

During the test, 300g of the slag sample was taken, crushed by a jaw crusher and a roller crusher until 80% passed through a sieve with a mesh size of 3.0 mm, mixed and divided, and 10% reduced coal and 40% slag mass were added. Pyrite, stir evenly and put it into an 800ml crucible, place it in a muffle furnace at 1200°C, roast statically for 2 hours, cool naturally, and weigh it. The grinding fineness is -0.075mm, accounting for 75%, and the magnetic field strength is 95.54KA/m. Magnetic separation was carried out under the conditions to obtain cobalt concentrate with a grade of 5.15%, a recovery rate of 89.38%, and an enrichment of more than 3 times.

Take another 500g slag sample, crush it with a jaw crusher and a roller crusher until 80% passes through a sieve with a mesh size of 3.0mm, mix and reduce it, and add 10% reduced coal and 40% pyrite by mass of the slag. , stir evenly and then put it into a rotary kiln with a diameter of 90mm, dynamic roasting at 1200°C for 2 hours, put it into water to cool, dry and weigh, and carry out magnetic separation at a grinding fineness of -0.075mm accounting for 75% and a magnetic field strength of 95.54KA/m. , the cobalt concentrate grade was obtained at 5.02%, the recovery rate was 88.87%, and the concentration was more than 3 times.

Example 2.

The sample comes from the Democratic Republic of the Congo. The main components (mass percentage): Co 1.29%, Fe 47.02%, Cu 1.01%, SiO ₂ 29.93%, CaO 0.639%, MgO 0.585%, S 0.060%.

During the test, 300g of the slag sample was taken, crushed by a jaw crusher and a roller crusher until 80% passed through a sieve with a mesh size of 3.0 mm, mixed and divided, and 8% reduced coal and 50% slag mass were added. Pyrite, stir evenly and put it into an 800ml crucible, place it in a muffle furnace at 1150°C, roast statically for 2 hours, cool naturally, and weigh it. The grinding fineness is -0.075mm, accounting for 75%, and the magnetic field strength is 95.54KA/m. Under magnetic separation, the cobalt concentrate was obtained with a grade of 4.01%, a recovery rate of 92.66%, and an enrichment of more than 3 times.

Take another 500g slag sample, crush it with a jaw crusher and a roller crusher until 80% passes through a sieve with a mesh size of 3.0mm, mix and reduce it, and add 8% reduced coal and 50% pyrite by mass of the slag. , stir evenly and then put it into a rotary kiln with a diameter of 90mm, dynamic roasting at 1150°C for 2 hours, put it into water to cool, dry and weigh, and carry out magnetic separation at a grinding fineness of -0.075mm accounting for 75% and a magnetic field strength of 95.54KA/m. , the cobalt concentrate grade was obtained at 4.26%, the recovery rate was 90.67%, and the concentration was more than 3 times.

Example three.

The sample comes from Zambia. The main components (mass percentage): Co 1.15%, Fe 45.47%, Cu 3.69%, SiO ₂ 27.65%, CaO 0.587%, MgO 0.395%, S 0.129%.

During the test, 300g of the slag sample was taken, crushed by a jaw crusher and a roller crusher until 80% passed through a sieve with a mesh size of 3.0 mm, mixed and divided, and 10% reduced coal and 45% slag mass were added. Pyrite, stir evenly and put it into an 800ml crucible, place it in a muffle furnace at 1250°C, statically roast for 1.5 hours, cool naturally, and weigh it. The grinding fineness is -0.075mm, accounting for 75%, and the magnetic field strength is 95.54KA/ Magnetic separation was carried out under m, and the cobalt concentrate grade was obtained at 4.57%, with a recovery rate of 93.87% and an enrichment of more than 3 times.

Take another 500g slag sample, crush it with a jaw crusher and a roller crusher until 80% passes through a sieve with a mesh size of 3.0mm, mix and reduce, add 10% reduced coal and 45% pyrite by mass of slag. After stirring evenly, put it into a rotary kiln with a diameter of 90mm, dynamic roasting at 1250°C for 1.5 hours, put it into water to cool, dry and weigh, and carry out magnetic separation at a grinding fineness of -0.075mm accounting for 75% and a magnetic field strength of 95.54KA/m. , the cobalt concentrate grade was obtained at 4.63%, the recovery rate was 92.99%, and the concentration was more than 3 times.

It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that these entities or operations are mutually exclusive. any such actual relationship or sequence exists between them. Furthermore, the terms "comprises," "comprises," or any other variations thereof are intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also those not expressly listed other elements, or elements inherent to the process, method, article or equipment. Without further limitation, an element defined by the statement "comprises a..." does not exclude the presence of additional identical elements in a process, method, article, or apparatus that includes the stated element.

Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art will understand that various changes, modifications, and substitutions can be made to these embodiments without departing from the principles and spirit of the invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (6)

1. A method for recovering cobalt from a cobalt-containing slag, comprising the steps of:

s1: preparing a converter slag sample;

s2: reduction roasting test research;

s3: mineral separation enrichment test research.

2. The method for recovering cobalt from cobalt-containing slag according to claim 1, wherein the converter slag sample preparation in step S1 specifically comprises:

because the grain size of the slag sample is larger, the slag sample is required to be treated, the slag sample is crushed to 80 percent by a jaw crusher and a roller crusher and passes through a sieve with the mesh size of 3.0mm, and then the slag sample is uniformly mixed, reduced and sampled for standby.

3. The method for recovering cobalt from cobalt-containing slag according to claim 1, wherein the reduction roasting test study in step S2 is specifically;

carrying out static reduction condition test, namely taking 300g of slag sample each time, preparing a certain proportion of reducing agent, uniformly stirring, putting into a 800ml crucible, then putting into a muffle furnace for static roasting, taking out after heating and heat preservation are completed, naturally cooling, weighing after the materials are thoroughly cooled, and carrying out magnetic separation;

and (3) carrying out dynamic verification test on the rotary kiln, taking 500g of slag sample each time, adding a reducing agent, putting into the rotary kiln with the diameter of 90mm for dynamic roasting, taking out after the temperature rise and the heat preservation are completed, putting into water for cooling, drying and weighing after the materials are thoroughly cooled, and carrying out magnetic separation.

4. The method for recovering cobalt from cobalt-containing slag according to claim 1, wherein the beneficiation enrichment test study in step S3 is specifically:

and (3) carrying out magnetic separation under the condition that the grinding fineness is 75 percent of-0.075 mm and the magnetic field strength is 95.54KA/m, so as to obtain magnetic concentrate.

5. The method for recovering cobalt using a cobalt-containing slag according to claim 1, wherein the reducing agent in the step S2 comprises pyrite and reduced coal; the addition mass of the reducing coal is 8-11% of the mass of the slag, and the addition mass of the pyrite is 40-50% of the mass of the slag.

6. The method for recovering cobalt from a cobalt-containing slag according to claim 1, wherein the roasting temperature in the step S2 is 1150 ℃ to 1300 ℃ and the reduction time is 1.5h to 2.5h.