Waste heat recycling system in cobalt extraction, purification and iron removal process and application of waste heat recycling system

Abstract

The invention discloses a waste heat recycling system in the cobalt extraction, purification and iron removal process and application of the waste heat recycling system, and the process application process of the whole device is as follows: after a solution from an iron-removed liquid is pumped to a waste heat exchange plate for exchange, heat is transferred to chilled water on the evaporation side of a heat pump unit; the temperature of chilled water on the evaporation side of the heat pump is increased through waste heat from the iron-removed liquid; the heat pump transfers heat to the heat pump condenser side through a refrigerant medium; the temperature from the evaporation side of the heat pump and the heat of a heat pump compressor increase the temperature of circulating water on the condenser side of the heat pump; and the cobalt raw material leachate is heated by circulating water from a heat pump condenser side through heat supply plate exchange. And the iron-removed liquid enters an extraction process due to the fact that heat is taken away and the temperature is reduced, the waste heat of the iron-removed liquid is recycled for heating the cobalt raw material dissolving solution through the technology, and the processing cost of cobalt extraction is reduced.

Description

Technical Field

[0001] This invention belongs to the field of non-ferrous hydrometallurgical process technology, specifically relating to a waste heat recovery system and its application in the cobalt extraction, purification and iron removal process. Background Technology

[0002] The cobalt extraction process for removing iron involves adding oxidant and neutralizing agent to the dissolved liquid, controlling the temperature (80-90℃) and pH value of the reaction process. After iron removal, the liquid is cooled (45-50℃) by pressure filtration, fine filtration, and plate heat exchanger. The liquid is then used as copper material in the P204 extraction process, and the iron slag is returned to the raw material area for washing after slurrying. Although the extraction process is relatively mature, there are some problems in terms of energy utilization: (1) After iron removal and pressure filtration, the liquid is cooled by plate heat exchanger and then enters the extraction tank, and the residual heat is not utilized. (2) The steam consumption for heating the solution in the iron removal process is 3.5t / tCo, which is high and leads to increased cobalt processing costs.

[0003] Therefore, it is necessary to design a waste heat recovery system and its application in the cobalt extraction and purification process for iron removal, so as to reduce the amount of steam used in the iron removal process and thus reduce production costs. Summary of the Invention

[0004] To address the problems of existing technologies, the purpose of this invention is to provide a waste heat recovery system and its application in the cobalt extraction, purification, and iron removal process, so as to solve the problem that the latent heat after iron removal cannot be effectively utilized.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A waste heat recovery system for cobalt extraction and purification iron removal process includes several iron removal tanks. Each iron removal tank is connected to a heating plate heat exchanger. A heat pump unit is connected to the outlet of the heating plate heat exchanger. The heat pump unit includes a condenser and an evaporator. The outlet of the evaporator of the heat pump unit is connected to the inlet of the heating heat exchanger. The outlet of the condenser of the heat pump unit is connected to a waste heat plate heat exchanger. The outlet of the waste heat plate heat exchanger is connected to the inlet of the condenser of the heat pump unit. The outlet of the waste heat plate heat exchanger is connected to the outlet of the condenser of the heat pump unit. The outlet of the waste heat plate heat exchanger is connected to the iron removal tank.

[0006] More preferably, the heat pump unit is connected to an expansion tank.

[0007] More preferably, the inlet of the heating plate heat exchanger and the inlet of the waste heat plate heat exchanger are connected to a backwash hydrochloric acid solution tank.

[0008] More preferably, it also includes the application of a waste heat recovery system in the cobalt extraction, purification, and iron removal process, comprising the following steps: (1) The solution enters the waste heat exchanger through the second inlet of the waste heat plate heat exchanger for heat exchange and temperature rise. After the temperature of the solution rises, it is discharged from the waste heat plate heat exchanger through the second outlet of the waste heat plate heat exchanger. The solution enters several iron removal tanks for iron removal. (2) The iron-removed liquid generated in step (1) enters the heating plate heat exchanger through the inlet of the heating plate heat exchanger for heat exchange and cooling. After the temperature of the iron-removed liquid decreases, it is discharged from the heating plate heat exchanger through the outlet of the heating plate heat exchanger and enters the extraction process. (3) The chilled water in the heat pump unit evaporator enters the heating plate heat exchanger through the second inlet of the heating plate heat exchanger. The chilled water absorbs the heat provided in step (2) and heats up in the heating plate heat exchanger. The heated chilled water is discharged from the heating plate heat exchanger through the second inlet of the heating plate heat exchanger and then enters the heat pump unit evaporator again. (4) The heat absorbed by the heat pump unit evaporator in step (3) is transferred to the heat pump unit condenser through the heat pump refrigerant and compressor, and the circulating water temperature of the heat pump unit condenser increases. (5) The circulating water of the heat pump unit condenser heated in step (4) enters the waste heat plate heat exchanger through the inlet of the waste heat plate heat exchanger to exchange heat and provide heat for the solution in step (1). The cooled circulating water enters the heat pump unit condenser again.

[0009] Compared with the prior art, the present invention has the following advantages: This invention mainly utilizes plate heat exchangers and heat pump technology to heat the cobalt raw material leaching solution by using the waste heat of the iron removal liquid, thus achieving the purpose of waste heat recovery. The process of this invention is simple, and it can effectively achieve the purpose of waste heat recovery and utilization by using the waste heat of the iron removal liquid to heat the cobalt raw material leaching solution without consuming external steam. Attached Figure Description

[0010] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0012] A waste heat recovery system for cobalt extraction and purification iron removal processes includes several iron removal tanks. Each tank is connected to a heating plate heat exchanger. The iron-removed liquid discharged from the outlet of the heating plate heat exchanger is connected to the extraction process. A heat pump unit, including a condenser and an evaporator, is connected to the outlet of the heating plate heat exchanger. The evaporator outlet of the heat pump unit is connected to the inlet of the heating plate heat exchanger. The condenser outlet of the heat pump unit is connected to a waste heat plate heat exchanger. The outlet of the waste heat plate heat exchanger is connected to the inlet of the condenser of the heat pump unit. The outlet of the waste heat plate heat exchanger is connected to the outlet of the condenser of the heat pump unit. The outlet of the waste heat plate heat exchanger is connected to the iron removal tanks, and the dissolved liquid flows into the inlet of the waste heat plate heat exchanger. An expansion tank is connected to the heat pump unit. The outlet of the expansion tank is connected to the inlet pipelines of the condenser and evaporator of the heat pump unit. When the water level is too low, the expansion tank supplies water to the heat pump unit; when the water level is too low again, the expansion tank recycles the water. The inlet 1 of the heating plate heat exchanger and the inlet 2 of the waste heat plate heat exchanger are connected to a backwash hydrochloric acid solution tank. Hydrochloric acid is periodically introduced to remove scale and prevent the heat exchanger from clogging.

[0013] Example (1) The 55℃ solution enters the waste heat exchanger through the second inlet of the waste heat plate heat exchanger for heat exchange and temperature rise. The temperature of the solution rises to 85℃. The solution is discharged from the waste heat plate heat exchanger through the second outlet and enters several iron removal tanks for iron removal. (2) The temperature of the iron-removed liquid produced in step (1) is 80°C. The iron-removed liquid enters the heating plate heat exchanger through the inlet of the heating plate heat exchanger for heat exchange and cooling. When the temperature of the iron-removed liquid drops to 45°C, the iron-removed liquid is discharged from the heating plate heat exchanger through the outlet of the heating plate heat exchanger and enters the extraction process. (3) The chilled water at 55°C in the heat pump unit evaporator enters the heating plate heat exchanger through the second inlet of the heating plate heat exchanger. The chilled water absorbs the heat provided in step (2) and heats up in the heating plate heat exchanger. The chilled water heated to 60°C is discharged from the heating plate heat exchanger through the second inlet of the heating plate heat exchanger. The chilled water then enters the heat pump unit evaporator again. (4) The heat absorbed by the heat pump unit evaporator in step (3) is transferred to the heat pump unit condenser through the heat pump refrigerant and compressor, and the circulating water temperature of the heat pump unit condenser rises from 80°C to 90°C. (5) The circulating water of the heat pump unit condenser, which has been heated in step (4), enters the waste heat plate heat exchanger through the inlet of the waste heat plate heat exchanger to exchange heat and provide heat for the solution in step (1). The temperature of the solution rises from 55°C to 85°C. The cooled circulating water then enters the heat pump unit condenser again.

[0014] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A waste heat recovery system for cobalt extraction, purification, and iron removal processes, comprising several iron removal tanks, characterized in that: The iron removal tank is connected to a heating plate heat exchanger. The outlet of the heating plate heat exchanger is connected to a heat pump unit. The heat pump unit includes a condenser and an evaporator. The outlet of the evaporator of the heat pump unit is connected to the inlet of the heating heat exchanger. The outlet of the condenser of the heat pump unit is connected to a waste heat plate heat exchanger. The outlet of the waste heat plate heat exchanger is connected to the inlet of the condenser of the heat pump unit. The outlet of the waste heat plate heat exchanger is connected to the iron removal tank.

2. The waste heat recovery system in the cobalt extraction, purification, and iron removal process according to claim 1, characterized in that: The heat pump unit is connected to an expansion tank.

3. The waste heat recovery system in the cobalt extraction, purification, and iron removal process according to claim 1, characterized in that: The inlet 1 of the heating plate heat exchanger and the inlet 2 of the waste heat plate heat exchanger are connected to a plate heat exchanger backwash hydrochloric acid solution tank.

4. It also includes the application of a waste heat recovery system in the cobalt extraction, purification, and iron removal process, characterized in that, Includes the following steps: Step 1: The solution enters the waste heat plate heat exchanger through inlet 2 for heat exchange and temperature increase. After the temperature of the solution increases, it is discharged from the waste heat plate heat exchanger through outlet 2. The solution then enters several iron removal tanks for iron removal. Step 2: The iron-removed liquid produced in Step 1 enters the heating plate heat exchanger through the inlet 1 for heat exchange and cooling. After the temperature of the iron-removed liquid decreases, it is discharged from the heating plate heat exchanger through the outlet 1 and enters the extraction process. Step 3: The chilled water in the heat pump unit evaporator enters the heat exchanger through the second inlet of the heat exchanger. The chilled water absorbs the heat provided in step 2 and exchanges heat in the heat exchanger to raise its temperature. The heated chilled water is discharged from the heat exchanger through the second inlet of the heat exchanger and then enters the heat pump unit evaporator again. Step 4: The heat absorbed by the evaporator in step 3 is transferred to the condenser of the heat pump unit through the heat pump refrigerant and compressor, and the circulating water temperature of the condenser of the heat pump unit rises. Step 5: The circulating water from the heat pump unit condenser, which has been heated in Step 4, enters the waste heat plate heat exchanger through the inlet to exchange heat and provide heat for the dissolved liquid in Step 1. The cooled circulating water then re-enters the heat pump unit condenser.

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