阅读说明：本技术 处理沉钴溶液的方法 (Method for treating cobalt precipitation solution ) 是由 李俊 殷书岩 王魁珽 傅建国 陆业大 戴江洪 孙宁磊 刘国 彭建华 于 2019-10-28 设计创作，主要内容包括：本发明公开一种处理沉钴溶液的方法,包括：(1)将沉钴溶液与石灰乳混合沉淀,以便得到液固混合物；(2)将所述液固混合物进行浓密处理,以便得到含氢氧化钴沉淀的溢流和含硫酸钙的底流；(3)将所述含氢氧化钴沉淀的溢流进行过滤,以便得到氢氧化钴和滤液。该方法采用石灰乳作为沉淀剂,简化了现有沉钴工序,且相比于现有沉钴技术,吨钴生产成本节省不少于2000元,同时能使钴的直收率达到96％,效果显著,且可大流量处理,适于工业生产应用。(The invention discloses a method for treating cobalt precipitation solution, which comprises the following steps: (1) mixing the cobalt precipitation solution with lime cream for precipitation so as to obtain a liquid-solid mixture; (2) carrying out thickening treatment on the liquid-solid mixture so as to obtain overflow containing cobalt hydroxide precipitate and underflow containing calcium sulfate; (3) and filtering the overflow containing the cobalt hydroxide precipitate so as to obtain cobalt hydroxide and filtrate. The method adopts lime milk as a precipitator, simplifies the existing cobalt precipitation process, saves the production cost of cobalt per ton by not less than 2000 yuan compared with the existing cobalt precipitation technology, simultaneously enables the direct yield of cobalt to reach 96%, has obvious effect, can treat the cobalt in large flow, and is suitable for industrial production and application.)

1. A method of treating a cobalt precipitation solution, the cobalt precipitation solution comprising cobalt sulfate, the method comprising:

(1) mixing the cobalt precipitation solution with lime cream for precipitation so as to obtain a liquid-solid mixture;

(2) carrying out thickening treatment on the liquid-solid mixture so as to obtain overflow containing cobalt hydroxide precipitate and underflow containing calcium sulfate;

(3) and filtering the overflow containing the cobalt hydroxide precipitate so as to obtain cobalt hydroxide and filtrate.

2. The method of claim 1, wherein the cobalt precipitation solution is obtained by sulfuric acid leaching of a cobalt-containing material.

3. The method according to claim 1 or 2, wherein in the step (1), the cobalt content in the cobalt precipitation solution is 1-20g/L, and the calcium oxide content in the lime milk is 10-40 g/L.

4. The method according to claim 1, wherein in the step (1), the molar ratio of the cobalt in the cobalt precipitation solution to the calcium oxide in the milk of lime is 0.8-1.2: 1.

5. the method according to claim 1, wherein, in the step (2), the thickening treatment includes a multi-stage thickening treatment;

optionally, in the step (2), the concentration treatment includes two-stage concentration treatment:

(2-1) subjecting the liquid-solid mixture to a first-stage thickening treatment to obtain a first underflow and a first overflow containing a cobalt hydroxide precipitate;

(2-2) subjecting the first underflow to a secondary thickening treatment so as to obtain the underflow containing calcium sulfate and an overflow containing a second cobalt hydroxide precipitate; the overflow stream comprising the cobalt hydroxide precipitate comprises an overflow stream of the first cobalt hydroxide precipitate and an overflow stream of the second cobalt hydroxide precipitate.

6. The method according to claim 1, wherein in step (3), the cobalt hydroxide has a cobalt content of not less than 35 wt% and a calcium content of not more than 6 wt%;

optionally, in step (3), the cobalt content of the filtrate is no more than 5 ppm.

7. The process according to claim 1, characterized in that at least a part of the filtrate obtained in step (3) is returned to step (1).

8. The method of claim 1, further comprising:

(4) and (3) pickling the underflow containing the calcium sulfate, and filtering to obtain pickled liquid and the calcium sulfate.

9. The method of claim 8, further comprising: returning at least a portion of the calcium sulfate to step (1).

10. The method according to claim 8, wherein in step (4), the calcium sulfate has a calcium content of not less than 25 wt% and a cobalt content of not more than 0.05 wt%.

Technical Field

The invention belongs to the technical field of wet metallurgy, and particularly relates to a method for treating a cobalt precipitation solution.

Background

The main stream processing technology of the low-grade cobalt ore in Indonesia and Philippine bands is the preparation of cobalt hydroxide after wet leaching, and in the process of preparing the cobalt hydroxide, adopted precipitants are mainly magnesium oxide and sodium hydroxide, the cost of the precipitants is high, sodium and magnesium can be accumulated after long-term operation, the influence on a system is caused, further, the magnesium precipitation by lime or the sodium discharge by evaporation is required, the process flow is long, and the cost is high. Specifically, for example, sodium hydroxide is used as a precipitator to react with a cobalt sulfate solution to prepare a cobalt hydroxide product, a flocculating agent is added to improve the settling property of the cobalt hydroxide, and the cobalt hydroxide product is obtained through concentration and filtration. In the process, the sodium content of the system is high due to the fact that the sodium hydroxide is used as a precipitator for precipitating cobalt, the system is influenced after long-term operation, therefore, evaporation is needed for discharging the sodium, the price of the sodium hydroxide precipitator is high, and meanwhile, a flocculating agent needs to be added in subsequent concentration, so that the operation cost is high. Other separation methods, such as cyclone separation, are limited by separation principles and equipment structures, cannot process large flows, and are limited in application.

Therefore, the existing technology for treating the cobalt precipitation solution needs to be further improved.

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. To this end, an object of the present invention is to propose a method for treating a cobalt precipitation solution. The method adopts lime milk as a precipitator, simplifies the existing cobalt precipitation process, saves the production cost of cobalt per ton by not less than 2000 yuan compared with the existing cobalt precipitation technology, simultaneously enables the direct yield of cobalt to reach 96%, has obvious effect, can treat the cobalt in large flow, and is suitable for industrial production and application.

In one aspect of the invention, the invention provides a method of treating a cobalt deposition solution containing cobalt sulfate, according to an embodiment of the invention, the method comprising:

(1) mixing the cobalt precipitation solution with lime cream for precipitation so as to obtain a liquid-solid mixture;

(2) carrying out thickening treatment on the liquid-solid mixture so as to obtain overflow containing cobalt hydroxide precipitate and underflow containing calcium sulfate;

(3) and filtering the overflow containing the cobalt hydroxide precipitate so as to obtain cobalt hydroxide and filtrate.

According to the method for treating the cobalt precipitation solution, the cobalt precipitation solution is mixed with the lime cream, cobalt sulfate in the cobalt precipitation solution can react with calcium hydroxide in the lime cream to generate calcium sulfate and cobalt hydroxide, both the calcium sulfate and the cobalt hydroxide are solid precipitates, and the lime cream is used as a precipitator, so that the cost is low, and the operation of subsequent processes cannot be influenced; the liquid-solid mixture containing the calcium sulfate precipitate and the cobalt hydroxide precipitate is subjected to thickening treatment, so that the calcium sulfate precipitate and the cobalt hydroxide precipitate have very small particles, but the calcium sulfate exists in a crystal form, and the cobalt hydroxide is in a flocculent state, the sedimentation velocity of the cobalt hydroxide is different from that of the cobalt hydroxide, the sedimentation velocity of the calcium sulfate is higher than that of the cobalt hydroxide, the cobalt hydroxide precipitate and the calcium sulfate precipitate can be separated after the thickening treatment, namely the cobalt hydroxide and the calcium sulfate can be separated by adopting the thickening treatment without adding a flocculating agent, and the cost for producing the cobalt hydroxide is further reduced. Therefore, the method adopts lime milk as a precipitator, simplifies the existing cobalt precipitation process, saves the production cost of cobalt per ton by not less than 2000 yuan compared with the existing cobalt precipitation technology, simultaneously enables the direct yield of cobalt to reach 96 percent, has obvious effect, can treat the cobalt in large flow, and is suitable for industrial production application.

In addition, the method for treating the cobalt precipitation solution according to the above embodiment of the present invention may further have the following additional technical features:

in some embodiments of the invention, the cobalt precipitation solution is obtained by leaching cobalt-containing materials with sulfuric acid.

In some embodiments of the invention, in the step (1), the cobalt content in the cobalt precipitation solution is 1-20g/L, and the calcium oxide content in the milk lime is 10-40 g/L.

In some embodiments of the invention, in step (1), the molar ratio of cobalt in the cobalt precipitation solution to calcium oxide in the milk of lime is 0.8-1.2: 1.

in some embodiments of the invention, in step (2), the densification process comprises a multi-stage densification process.

In some embodiments of the present invention, in step (2), the thickening treatment comprises a two-stage thickening treatment: (2-1) subjecting the liquid-solid mixture to a first-stage thickening treatment to obtain a first underflow and a first overflow containing a cobalt hydroxide precipitate; (2-2) subjecting the first underflow to a secondary thickening treatment so as to obtain the underflow containing calcium sulfate and an overflow containing a second cobalt hydroxide precipitate; the overflow stream comprising the cobalt hydroxide precipitate comprises an overflow stream of the first cobalt hydroxide precipitate and an overflow stream of the second cobalt hydroxide precipitate.

In some embodiments of the invention, in step (3), the cobalt hydroxide has a cobalt content of not less than 35 wt% and a calcium content of not more than 6 wt%.

In some embodiments of the invention, in step (3), the cobalt content of the filtrate is no greater than 5 ppm.

In some embodiments of the invention, at least a portion of the filtrate from step (3) is returned to step (1).

In some embodiments of the present invention, the method for treating a cobalt precipitation solution further comprises: (4) and (3) pickling the underflow containing the calcium sulfate, and filtering to obtain pickled liquid and the calcium sulfate.

In some embodiments of the present invention, the method for treating a cobalt precipitation solution further comprises: returning at least a portion of the calcium sulfate to step (1).

In the method for treating the cobalt precipitation solution, in the step (4), the calcium content in the calcium sulfate is not less than 25 wt%, and the cobalt content is not more than 0.05 wt%.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic flow diagram of a method for treating a cobalt precipitation solution according to one embodiment of the present invention;

FIG. 2 is a schematic flow diagram of a method for treating a cobalt deposition solution according to yet another embodiment of the present invention;

FIG. 3 is a schematic flow diagram of a method for treating a cobalt deposition solution according to yet another embodiment of the present invention;

FIG. 4 is a schematic flow diagram of a method of treating a cobalt deposition solution according to yet another embodiment of the present invention;

fig. 5 is a schematic flow chart of a method for treating a cobalt precipitation solution according to another embodiment of the invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

In one aspect of the invention, the invention provides a method of treating a cobalt deposition solution containing cobalt sulfate, the method comprising, in accordance with an embodiment of the invention, with reference to fig. 1:

s100: mixing the cobalt precipitation solution with lime milk for precipitation

In the step, the cobalt precipitation solution is mixed with lime milk for precipitation so as to obtain a liquid-solid mixture. The inventor finds that the cobalt sulfate in the cobalt precipitation solution can react with the calcium hydroxide in the lime milk to generate calcium sulfate and cobalt hydroxide by mixing the cobalt precipitation solution with the lime milk, the calcium sulfate and the cobalt hydroxide are solid precipitates, and the lime milk is used as a precipitator, so that the cost is low, and the operation of the subsequent process is not influenced. Compared with the prior subsequent process of further precipitating magnesium by lime or evaporating to discharge sodium, the process is simplified, and the operation cost is obviously reduced.

According to an embodiment of the present invention, the source of the cobalt precipitation solution is not particularly limited, and may be selected by those skilled in the art according to actual needs, for example, the cobalt precipitation solution may be obtained by leaching cobalt-containing material with sulfuric acid, such as cobalt-containing mineral with sulfuric acid. Further, the content of cobalt in the cobalt precipitation solution and the content of calcium oxide in the milk of lime are not particularly limited, for example, the content of cobalt in the cobalt precipitation solution may be 1 to 20g/L, such as 1g/L, 5g/L, 10g/L, 15g/L, 20g/L, and the content of calcium oxide in the milk of lime may be 10 to 40g/L, such as 10g/L, 15g/L, 20g/L, 25g/L, 30g/L, 35g/L, 40 g/L. The inventor finds that if the cobalt content in the cobalt precipitation solution is too low, the treatment capacity is reduced, the equipment investment is increased, the process is not economical, if the cobalt content in the cobalt precipitation solution is too high, the product separation is difficult, and the calcium content in the cobalt hydroxide product is increased, so that the subsequent treatment is inconvenient.

According to still another embodiment of the present invention, the mass ratio of the cobalt precipitating solution to the lime milk is not particularly limited, and may be selected by those skilled in the art according to actual needs, for example, according to the content of cobalt in the cobalt precipitating solution to calcium hydroxide in the lime milk, and specifically, the molar ratio of cobalt in the cobalt precipitating solution to calcium oxide in the lime milk may be 0.8 to 1.2: 1. the inventor finds that if the cobalt precipitation solution is too much, the lime milk can not precipitate cobalt in the cobalt precipitation solution, so that the cobalt content in the underflow containing calcium sulfate is higher, and the process economy is also reduced; if the lime milk is too much, a large amount of unreacted calcium oxide is entrained in the product.

S200: the liquid-solid mixture is subjected to thickening treatment

In this step, the liquid-solid mixture is subjected to a thickening treatment so as to obtain an overflow containing the cobalt hydroxide precipitate and an underflow containing calcium sulphate. The inventor finds that by carrying out thickening treatment on a liquid-solid mixture containing calcium sulfate sediment and cobalt hydroxide sediment, because the particles of the calcium sulfate sediment and the cobalt hydroxide sediment are very small, but calcium sulfate exists in a crystal form, and the cobalt hydroxide is in a flocculent state, the sedimentation velocity of the calcium sulfate is different from that of the cobalt hydroxide, the sedimentation velocity of the calcium sulfate is higher than that of the cobalt hydroxide, and after the thickening treatment, the cobalt hydroxide sediment and the calcium sulfate sediment can be separated, namely, the cobalt hydroxide and the calcium sulfate can be separated by adopting the thickening treatment without adding a flocculating agent, and the cost for producing the cobalt hydroxide is further reduced. Specifically, the thickening treatment may be performed by using a thickener. And in the process of carrying out thickening treatment on the liquid-solid mixture by the thickener, the rising speed of water flow in the thickener can be adjusted by adjusting the flow of underflow and overflow of the thickener, so that the aim of separating cobalt hydroxide and calcium sulfate is fulfilled. It should be noted that if the cobalt product needs to be reprocessed subsequently, the cobalt product can be leached by sulfuric acid without separation after the cobalt is precipitated by lime cream, and then the leaching is carried out by filtering to obtain high-concentration cobalt sulfate solution and gypsum residue, and the high-concentration cobalt sulfate solution is further processed, and the gypsum residue is piled up.

Further, the specific number of the thickening treatment is not particularly limited, and a person skilled in the art can select the thickening treatment according to actual needs, for example, the thickening treatment can be adjusted according to the acid consumption of the calcium sulfate-containing underflow acid washing and the direct yield of cobalt, and as the number of the thickening separation stages increases, the acid consumption of the subsequent calcium sulfate-containing underflow acid washing decreases, and the direct yield of cobalt increases. According to one embodiment of the invention, a multi-stage densification process may be included. Specifically, according to an embodiment of the present invention, referring to fig. 2, two-stage densification may be included:

s210: subjecting the liquid-solid mixture to primary thickening treatment

In this step, the liquid-solid mixture is subjected to a first thickening treatment so as to obtain a first underflow and a first overflow containing a cobalt hydroxide precipitate. Wherein the first underflow is predominantly calcium sulfate with a small amount of cobalt hydroxide also entrained. Thus, the cobalt hydroxide and the calcium sulfate in the liquid-solid mixture can be separated preliminarily.

S220: the first underflow is subjected to secondary thickening treatment

In the step, the first underflow is subjected to a secondary thickening treatment so as to obtain an underflow containing calcium sulfate and an overflow containing a second cobalt hydroxide precipitate, and the overflow containing the cobalt hydroxide precipitate comprises the overflow containing the first cobalt hydroxide precipitate and the overflow containing the second cobalt hydroxide precipitate. Therefore, the separation of cobalt hydroxide and calcium sulfate can be further realized, and the direct yield of cobalt is improved.

S300: filtering the overflow containing cobalt hydroxide precipitate

In this step, the overflow containing the cobalt hydroxide precipitate is filtered to obtain cobalt hydroxide and a filtrate. Thereby, the recovery of cobalt is achieved. Further, referring to fig. 3, at least a portion of the resulting filtrate may be returned to step S100 for reuse. The inventors have conducted extensive studies and found that by using the above-mentioned treatment method of the present application, the cobalt content in the obtained cobalt hydroxide is not less than 35 wt%, the calcium content is not more than 6 wt%, and the cobalt content in the filtrate is not more than 5 ppm. Namely, the method for treating the cobalt precipitation solution has high direct yield and obvious effect.

According to the method for treating the cobalt precipitation solution, the cobalt precipitation solution is mixed with the lime cream, cobalt sulfate in the cobalt precipitation solution can react with calcium hydroxide in the lime cream to generate calcium sulfate and cobalt hydroxide, both the calcium sulfate and the cobalt hydroxide are solid precipitates, and the lime cream is used as a precipitator, so that the cost is low, and the operation of subsequent processes cannot be influenced; the liquid-solid mixture containing the calcium sulfate precipitate and the cobalt hydroxide precipitate is subjected to thickening treatment, so that the calcium sulfate precipitate and the cobalt hydroxide precipitate have very small particles, but the calcium sulfate exists in a crystal form, and the cobalt hydroxide is in a flocculent state, the sedimentation velocity of the cobalt hydroxide is different from that of the cobalt hydroxide, the sedimentation velocity of the calcium sulfate is higher than that of the cobalt hydroxide, the cobalt hydroxide precipitate and the calcium sulfate precipitate can be separated after the thickening treatment, namely the cobalt hydroxide and the calcium sulfate can be separated by adopting the thickening treatment without adding a flocculating agent, and the cost for producing the cobalt hydroxide is further reduced. Therefore, the method adopts lime milk as a precipitator, simplifies the existing cobalt precipitation process, saves the production cost of cobalt per ton by not less than 2000 yuan compared with the existing cobalt precipitation technology, simultaneously enables the direct yield of cobalt to reach 96 percent, has obvious effect, can treat the cobalt in large flow, and is suitable for industrial production application.

According to an embodiment of the present invention, referring to fig. 4, the method for treating a cobalt deposition solution further includes:

s400: pickling the underflow containing calcium sulfate

In the step, the underflow containing calcium sulfate is subjected to acid washing and filtered to obtain acid washing liquid and calcium sulfate. The inventors have found that by subjecting the underflow containing calcium sulphate to an acid wash, impurities on the surface of the calcium sulphate can be washed away. Further, referring to fig. 5, at least a portion of the obtained calcium sulfate may be returned to S100 to be used as a seed crystal, thereby facilitating the reaction of cobalt sulfate and calcium hydroxide in S100 and increasing the precipitation rate. And the inventor finds that the calcium content in the calcium sulfate obtained after acid cleaning is not less than 25 wt% and the cobalt content is not more than 0.05 wt% through a great deal of research. Namely, the method has remarkable cobalt yield when being used for treating the cobalt precipitation solution. Further, the specific type of acid used for acid washing is not particularly limited, and may be selected by those skilled in the art according to actual needs, for example, sulfuric acid, so that even if the obtained calcium sulfate is returned to step S100 to be used as a seed crystal, no impurities are introduced, and the smooth running of the reaction is facilitated.

In the present application, the absolute temporal context is not shown between steps (1), (2), (3), and (4) and S100, S200, S300, and S400.

The invention will now be described with reference to specific examples, which are intended to be illustrative only and not to be limiting in any way.