Cobalt salt solution variable-temperature combined oil removal process

Abstract

The invention discloses a cobalt salt solution variable-temperature combined oil removal process which comprises the following steps: step 1, cooling and air-floating oil removal: cooling cobalt raffinate through cooling water heat exchange, then carrying out ultrasonic-air-floating oil removal, and clarifying and separating to obtain primary oil-removed liquid; step 2, heating, oxidizing and deoiling: heating the primary deoiled liquid obtained in the step 1 through hot water heat exchange, oxidizing and deoiling, cooling with cooling water after oxidizing and deoiling, and clarifying and separating to obtain secondary deoiled liquid. And step 3, adsorption and oil removal: introducing the secondary oil-removed liquid obtained in the step 3 into an oil removal column, and filling two layers of oil removal substances in the oil removal column to obtain an oil-removed cobalt salt solution. The oil removal effect of the cobalt salt solution can be effectively improved, the equipment utilization efficiency is improved, the replacement period of the fiber balls and the activated carbon is prolonged, and the material loss is reduced.

Description

Technical Field

[0001] The invention belongs to the field of hydrometallurgy and provides a cobalt salt solution temperature-variable combined oil removal process. Background Art

[0002] At present, my country's cobalt metal smelting is mainly based on the wet method, which mainly uses leaching and iron removal processes to treat cobalt raw materials. Organic extractants such as P204 and P507 are used to remove impurities through extraction and removal of other impurity metal ions in the leachate to produce a cobalt salt solution. Extraction is a process in which the organic phase and the aqueous phase are mixed and then separated. In industrial continuous production, it is inevitable that the cobalt salt solution produced contains organic matter. Therefore, degreasing the cobalt salt solution is a major problem in the industry.

[0003] The cobalt salt solution produced by extraction mainly contains the following four types of oil: suspended oil, dispersed oil, emulsified oil and dissolved oil. At present, the industry mainly adopts static oil removal to remove suspended oil and dispersed oil, ultrasonic oil removal to remove emulsified oil, catalytic oxidation oil removal and activated carbon adsorption oil removal to remove dissolved oil. However, due to certain requirements on the temperature in the extraction box during extraction production, the temperature of the cobalt raffinate produced is 40°C, slightly higher than room temperature. Experimental verification shows that the ultrasonic-flotation oil removal effect is poor at this time, and the dissolved oil content is high, resulting in a short saturation cycle of fiber balls and activated carbon, frequent replacement, and consumption of a lot of manpower and material resources. At the same time, a large amount of hazardous waste is generated, which is not conducive to environmental protection.

[0004] Based on experimental verification, the present invention adopts a tubular heat exchanger to perform temperature-variable treatment on the cobalt salt solution, so that the oil removal effect of each oil removal process is improved, the equipment utilization efficiency is improved, the replacement cycle of fiber balls and activated carbon is extended, the material loss is reduced, and the generation of hazardous waste is reduced. Summary of the invention

[0005] The object of the present invention is to provide a process for temperature-variable combined degreasing of a cobalt salt solution to solve the problems existing in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions: The process of temperature-variable combined degreasing of cobalt salt solution of the present invention comprises the following steps: (1) Cooling and flotation oil removal: The cobalt raffinate is cooled to 20-25°C by a tubular heat exchanger and passed into a box-type flotation oil remover. After ultrasonic demulsification and flotation oil removal, it enters a clarification tank for oil-water separation to obtain a deoiled liquid; The cobalt raffinate is the output of the cobalt extraction process, mainly a mixed solution of cobalt chloride, cobalt sulfate, and cobalt nitrate. The temperature of the cobalt raffinate is 40°C, and the oil content before degreasing is 20ppm. The box-type degreasing device is a conventional ultrasonic-flotation degreasing device. The degreasing effect of the cobalt raffinate after cooling with cooling water and then passing through the box-type degreasing device is significantly improved. The cobalt raffinate is cooled by a tubular heat exchanger. On the one hand, the cobalt raffinate is cooled to room temperature (20°C) to ensure the effect of ultrasonic-flotation degreasing. On the other hand, the cooling water is preheated and then returned to the hot water tank for heating, saving some costs.

[0007] (2) Heating and oxidizing oil removal: The primary deoiled liquid obtained in step (1) is heated to 55-65°C by a tubular heat exchanger and passed into an oxidizing deoiler. The deoiler is filled with a catalyst and oxygen is passed into the primary deoiled liquid to remove oil. The deoiled liquid enters a clarification tank for oil-water separation to obtain a secondary deoiled liquid; The catalyst is activated carbon, and the oxidation deoiler is to heat the cobalt solution to 55-65°C and then react with oxygen under the catalytic action of the catalyst to break the organic matter in the cobalt solution, and then separate the oil and water in the clarifier. After the liquid is cooled down after the first deoiling, it is deoiled by ultrasonic-flotation to remove most of the emulsified oil, suspended oil, and dispersed oil. At this time, the tubular heat exchanger is used to increase the temperature, which will not significantly increase the dissolved oil content in the cobalt solution. At the same time, the cobalt solution can be heated to the reaction temperature of catalytic oxidation deoiling to ensure the deoiling effect.

[0008] (3) Deoiling by adsorption: The secondary deoiling liquid is cooled to 20-25°C through a tubular heat exchanger and passed into a deoiling column filled with two layers of deoiling material. After deoiling by adsorption, a deoiled cobalt salt solution is obtained.

[0009] The degreasing column is an ion exchange column filled with a double layer of degreasing material, which includes fiber balls and / or activated carbon. After the cobalt solution is cooled to room temperature by cooling water, the degreasing material has a significantly improved adsorption effect on organic matter. After the secondary degreasing liquid is cooled to room temperature (20°C), the dissolved oil content can be effectively reduced, and the remaining dissolved oil in the cobalt solution can be partially analyzed, thereby ensuring the adsorption effect of activated carbon and fiber balls and extending the service life.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows: the process of temperature-variable combined deoiling of a cobalt salt solution provided by the present invention, compared with directly deoiling the cobalt raffinate, maximizes the deoiling effect of each deoiling process through temperature-variable control, so that the cobalt salt solution with an oil content of 20 ppm before deoiling can reach 2 ppm after deoiling, and at the same time, prolongs the service life and use effect of the deoiling material (activated carbon, fiber balls, etc.) in the deoiling column, reduces the generation of hazardous waste, has good economic efficiency, and is beneficial to environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1is a process flow chart of the present invention; Figure 2 It is a connection diagram of the process equipment of the present invention. DETAILED DESCRIPTION

[0012] The following will describe the cobalt salt solution temperature-variable combined oil removal process in the present invention in conjunction with the drawings of the present invention's example description. The specific implementation described below is only one of all examples, and all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example

[0013] 1. The cobalt raffinate in the cobalt raffinate storage tank is passed through a tubular heat exchanger to control the temperature of the cobalt raffinate, and then passed into a box-type flotation deoiler. After ultrasonic demulsification and flotation deoiling, the cobalt raffinate enters a clarification tank for oil-water separation to obtain a deoiled liquid. The cobalt raffinate is the output of the cobalt extraction process, which is mainly a mixed solution of cobalt chloride, cobalt sulfate and cobalt nitrate. The temperature of the cobalt raffinate is 40°C, and the oil content before deoiling is 20ppm.

[0014] The temperature of the cobalt raffinate was controlled, and multiple groups of ultrasonic-flotation oil removal control tests of cobalt solutions at different temperatures were carried out to observe the oil removal effect of cobalt solutions at different temperatures. The results are shown in Table 1. The results show that the oil removal effect is best when the cobalt solution temperature is controlled at room temperature (20°C), and about 40% of the oil can be removed by ultrasonic-flotation oil removal. When the cobalt solution temperature is controlled at 30-40°C, the oil removal effect becomes worse, and only about 20%-30% of the oil can be removed by ultrasonic-flotation oil removal.

[0015] 2. The primary deoiled liquid obtained in step 1 is heated to 60° C. by a tubular heat exchanger, and passed into an oxidative deoiler filled with an activated carbon catalyst. Oxygen is passed into the primary deoiled liquid to deoil it. The deoiled solution enters a clarification tank for oil-water separation to obtain a secondary deoiled liquid; The three groups of solutions after ultrasonic-flotation oil removal were subjected to heating catalytic oxidation oil removal, and the oil removal effects of the three groups of solutions were observed. The results are shown in Table 2. The results show that about 40% of the oil in the cobalt solution has been removed in the solution after cooling ultrasonic-flotation oil removal (liquid after secondary oil removal-2), and this part of the oil is mostly suspended oil, dispersed oil, and emulsified oil. The more oil is removed by ultrasonic-flotation oil removal, the less oil is dissolved in the cobalt solution during heating catalytic oxidation oil removal, so the catalytic oxidation oil removal effect is the best. After ultrasonic-flotation oil removal of the two groups of solutions, liquid after secondary oil removal-1 and liquid after secondary oil removal-3, there are still some suspended oil, emulsified oil, and dispersed oil in the solution. After heating, the solubility of this part of oil increases and turns into dissolved oil, which is more difficult to remove, resulting in a poor catalytic oxidation oil removal effect.

[0016] 3. After the temperature of the secondary deoiled liquid is controlled by a tubular heat exchanger, it is passed into a deoiling column filled with two layers of deoiling material. After adsorption and deoiling, a deoiled cobalt salt solution is obtained; the deoiling column is an ion exchange column filled with a double layer of deoiling material, and the deoiling material is activated carbon.

[0017] In order to study the effect of temperature on the adsorption effect of activated carbon, a batch of the same cobalt solution was divided into multiple groups, and activated carbon was used for adsorption and oil removal after temperature treatment, and the results were statistically analyzed. The results are shown in Table 3. The results show that when the solution temperature is room temperature (20°C), the activated carbon adsorption effect is the best, the effect is second at 60°C, and the effect is poor at 40°C.

[0018] According to the experimental results of activated carbon temperature-variable oil removal, the three groups of solutions after catalytic oxidation oil removal were cooled to 20°C for activated carbon adsorption oil removal, and the results were statistically analyzed. The results are shown in Table 4. The results show that after cooling to 20°C, the oil content of the solution can be reduced to below 2ppm by activated carbon adsorption oil removal, and the oil removal effect is good. However, due to the different oil contents before oil removal, the saturation cycle of activated carbon is greatly affected. After cooling ultrasonic-flotation oil removal and heating catalytic oxidation, the oil content of the cobalt solution is significantly reduced, and the saturation cycle of activated carbon is significantly increased, which reduces material waste and labor while reducing the generation of hazardous waste.

[0019] In summary, the present invention first uses a tubular heat exchanger to cool the cobalt raffinate produced by the cobalt extraction production line to 20°C, and then performs ultrasonic-flotation oil removal, which ensures the equipment's oil removal effect on suspended oil, emulsified oil, and dispersed oil in the solution, and improves equipment utilization. Then, the cobalt solution from which most of the floating oil has been removed is subjected to heating catalytic oxidation oil removal, ensuring that the dissolved oil content will not increase significantly during the heating process, thereby ensuring the effect of catalytic oxidation oil removal. Finally, a small amount of oil (about 4ppm) remains in the cobalt solution after cooling ultrasonic-flotation oil removal and heating catalytic oxidation oil removal. At this time, the solution is cooled and adsorbed by activated carbon, which ensures the adsorption effect while greatly extending the saturation cycle of oil removal substances such as activated carbon, reducing the consumption of manpower and material resources, and reducing the generation of hazardous waste. At the same time, the water used for heat exchange in the present invention is recycled, and no other costs are generated except for the heating cost, which has good economic and environmental benefits.

[0020] The above are preferred embodiments of the present invention. Any simple modification, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A cobalt salt solution temperature variable combined degreasing process, characterized in that: The following steps are involved: (1) Cooling and flotation oil removal: The cobalt raffinate is cooled to 20-25°C by a tubular heat exchanger and passed into a box-type flotation oil remover. After ultrasonic demulsification and flotation oil removal, it enters a clarification tank for oil-water separation to obtain a deoiled liquid; (2) Heating and oxidizing oil removal: The primary deoiled liquid obtained in step (1) is heated to 55-65°C by a tubular heat exchanger and passed into an oxidizing deoiler. The deoiler is filled with a catalyst and oxygen is passed into the primary deoiled liquid to remove oil. The deoiled liquid enters a clarification tank for oil-water separation to obtain a secondary deoiled liquid; (3) Deoiling by adsorption: The secondary deoiling liquid is cooled to 20-25°C through a tubular heat exchanger and passed into a deoiling column filled with two layers of deoiling material. After deoiling by adsorption, a deoiled cobalt salt solution is obtained.

2. The cobalt salt solution temperature variable combined degreasing process according to claim 1, characterized in that: In step (1), the cobalt raffinate is the output of the cobalt extraction process, which is mainly a mixed solution of cobalt chloride, cobalt sulfate and cobalt nitrate. The temperature of the cobalt raffinate is 40° C., and the oil content before oil removal is 20 ppm.

3. The cobalt salt solution temperature variable combined degreasing process according to claim 1 is characterized in that: In step (1), the box-type oil remover is a conventional ultrasonic-flotation oil remover.

4. The cobalt salt solution temperature variable combined degreasing process according to claim 1, characterized in that: In step (2), the catalyst is activated carbon, and the oxidative deoiling device heats the cobalt solution to 55-65°C and then reacts with oxygen under the catalytic action of the catalyst to break the organic matter in the cobalt solution, and then separates the oil and water in a clarifier.

5. The cobalt salt solution temperature variable combined degreasing process according to claim 1, characterized in that: In step (3), the degreasing column is an ion exchange column filled with a double layer of degreasing material, and the degreasing material includes fiber balls and / or activated carbon; after the cobalt solution is cooled to room temperature by cooling water, the adsorption effect of the degreasing material on organic matter is significantly improved.

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