Nickel carbonate continuous preparation process in nickel electrolytic refining production system

Abstract

The invention discloses a continuous preparation process of nickel carbonate in a nickel electrolytic refining production system, which comprises the working procedures of preparation reaction, dense separation, precise filtration and belt filtration separation, and is characterized in that a nickel carbonate precipitate is produced through full reaction of an anolyte and a sodium carbonate solution in the nickel electrolytic refining production system; the nickel metal in the anolyte is ensured to be fully precipitated into nickel carbonate to be recycled, pulpified and reused by controlling key indexes such as proper reaction temperature, reaction time and reaction pH, and the supernate is mainly composed of sodium sulfate and is finally discharged, so that the method has important significance for ensuring sulfur balance, sodium balance and volume balance in a nickel electrolysis production system. The method has the advantages of being short in technological process, easy and convenient to operate, accurate in control and the like, the nickel content of the finally discharged nickel carbonate supernate is smaller than 0.025 g / L, the pH is 7-9, and the nickel metal recovery rate reaches 98% or above.

Description

Technical Field

[0001] The invention relates to a process for purifying and preparing nickel carbonate in a nickel hydrorefining process, and in particular to a process for continuously preparing nickel carbonate in a nickel electrolytic refining production system. Background Art

[0002] The traditional process of producing nickel carbonate by reacting sodium carbonate with nickel sulfate has always had problems such as inaccurate control of the reaction endpoint, large fluctuations in the amount of sodium carbonate added, unstable quality of the output nickel carbonate, low degree of automation, high production and operation costs, serious loss of valuable metals, and wastewater that cannot meet the standards stably. In response to the above problems, through many years of production practice, through efforts such as process improvement, automatic control improvement, equipment and facility transformation, a set of continuous preparation process for nickel carbonate and its control method have been formed. This method has the advantages of short process flow, simple operation, high degree of automation, precise control, efficient recovery of valuable metals, and stable wastewater discharge that meets the standards. Summary of the invention

[0003] The object of the present invention is a process for continuously preparing nickel carbonate in a nickel electrolytic refining production system.

[0004] A continuous preparation process of nickel carbonate in a nickel electrolytic refining production system comprises the following steps: A. Preparation reaction stage: The nickel electrolytic anolyte and sodium carbonate solution produced in the nickel electrolytic refining production system are introduced into the reaction tank for reaction at a temperature of 75-85°C for a reaction time of 4-5 hours, and the produced nickel carbonate slurry is transported to the thickening separation stage; The main component of the nickel electrolysis anolyte is nickel sulfate, in which the nickel content is 55-65g / L; the sodium carbonate content in the sodium carbonate solution is 140-150g / L; the nickel electrolysis anolyte and the sodium carbonate solution are continuously reacted in six reaction tanks 1# to 6#, the pH at the outlet of the 1# reaction tank is 7.0-7.5, and the pH at the outlet of the 6# reaction tank is 7.5-7.8; the flow rate of the nickel carbonate slurry is 30-35m 3 / h.

[0005] B. Thickening and separation stage: The nickel carbonate slurry is transported to the thickener for preliminary thickening and separation. The supernatant is a sodium sulfate solution, which is discharged to the precision filtration stage. The underflow slurry of the thickener is the nickel carbonate slurry, which is transported to the belt filtration separation stage; In order to ensure sufficient thickening and settling time, achieve effective separation of nickel carbonate precipitate and supernatant, and reduce nickel ion entrainment in the supernatant, the selected thickener is Φ18000mm with a settling area of ​​254m 2 / set, made of concrete lined fiberglass lined acid-resistant bricks.

[0006] C. Precision filtration stage: the supernatant separated from the thickener is first fed into a filter press for liquid-solid separation, and the clear liquid after filter press separation is fed into a precision filter for deep filtration, and the filtered clear liquid is discharged to a wastewater treatment station; the filter residues produced by the filter press and the precision filter are purified nickel carbonate; During the precision filtration stage, the nickel carbonate supernatant is deeply filtered using a filter press and precision filter to ensure that the nickel content of the nickel carbonate supernatant is less than 0.025g / L and is discharged to a wastewater treatment station.

[0007] D. Belt filtration separation stage: The underflow slurry separated from the thickener is transported to the belt filter for liquid-solid separation, and the filtrate of the belt filter is sent to the precision filtration section for deep filtration. The filter residue of the belt filter is the purified solid nickel carbonate. The water content (mass fraction) of the solid nickel carbonate is 20-25%.

[0008] The purified nickel carbonate produced in step C and step D is discharged into the slurry tank, and is mixed with new water, nickel electrolysis anode liquid produced by the nickel electrolysis production line, and filter washing water to prepare nickel carbonate slurry, which is sent to the acid dissolution and lead removal process for use. When preparing the nickel carbonate slurry, the temperature of the slurry tank is controlled at 75-85°C, and the liquid-solid ratio is 6-7:1. The prepared purified nickel carbonate is re-slurried and sent to the acid dissolution and lead removal process for use, so that some impurities (such as sodium, copper, iron, etc.) in the anode liquid of the nickel electrolysis production line are discharged open-circuit and nickel metal is recycled, ensuring the sulfur balance, sodium balance and volume balance of the nickel electrolytic refining production system.

[0009] Beneficial effects of the present invention: The process of the present invention includes preparation reaction, dense separation, precision filtration, and band filtration separation steps. Through the full reaction of the anolyte and the sodium carbonate solution in the nickel electrolysis production system, nickel carbonate precipitation is produced, and the appropriate reaction temperature, reaction time, reaction pH and other key indicators are controlled to ensure that the nickel metal in the anolyte is fully precipitated as nickel carbonate for recycling and slurrying, and the supernatant is mainly sodium sulfate. The supernatant is finally discharged, which is of great significance for ensuring the sulfur balance, sodium balance and volume balance in the nickel electrolysis production system. The method has the advantages of short process flow, simple operation, and precise control. The nickel content of the final discharged nickel carbonate supernatant is less than 0.025g / L, pH7-9, and the nickel metal recovery rate is more than 98%. The present invention realizes the discharge of some impurities in the anolyte of the nickel electrolysis production line together with the nickel carbonate supernatant and the full recycling of nickel metal, while maintaining the sulfur balance, sodium balance and volume balance of the nickel electrolytic refining production system. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0011] The present invention will be further described below in conjunction with specific embodiments.

[0012] Example 1 A. Preparation reaction stage: nickel electrolytic anolyte and sodium carbonate solution are passed into the reaction tank for reaction. The two solutions of nickel electrolytic anolyte and sodium carbonate solution are continuously reacted in six reaction tanks 1#~6#. The flow rate of nickel electrolytic anolyte is 18.9m 3 / h, nickel content 59.24g / L, sodium carbonate solution 14.1m 3 / h, sodium carbonate content 142.23g / L, pH 7.2 at the outlet of 1# reaction tank, temperature of 1#-6# reaction tanks 77-82℃, reaction time 5h, pH 7.6 at the outlet of 6# reaction tank, 32.51m 3 / h nickel carbonate slurry is transported to the dense separation stage.

[0013] The temperature in each reaction tank is interlocked with the steam valve, and the pH meter at the outlet of the 1# reaction tank is interlocked with the sodium carbonate solution flow meter to ensure stable control of temperature and pH during the preparation reaction stage.

[0014] B. Dense separation stage: nickel carbonate slurry flows at a flow rate of 32.51m 3 / h enters the thickener for thickening separation, the supernatant is sodium sulfate solution, and the flow rate of nickel carbonate supernatant is 17.33m 3 / h, pH 7.9, discharged to the fine filtration stage. The flow rate of nickel carbonate slurry in the thickener bottom flow is 14.62m 3 / h, and transported to the belt filtration separation stage.

[0015] C. Precision filtration stage: The supernatant separated from the thickener is first sent to the filter press for liquid-solid separation. The clear liquid after filter press separation is sent to the precision filter for deep filtration. The flow rate of the filtered clear liquid is 17.27m 3 / h, and the nickel carbonate supernatant after deep filtration contains 0.018g / L nickel, which meets the production requirements and is discharged to the wastewater treatment station. The filter residues produced by the filter press and precision filter are purified nickel carbonate, which are uniformly sent to the nickel carbonate slurry stage.

[0016] D. Belt filter separation stage: 14.62m3 of underflow slurry separated from the thickener 3 / h, and transported to the belt filter for liquid-solid separation. The filtrate from the belt filter is sent to the precision filtration section for deep filtration. The filter residue from the belt filter is about 10.3t / h of purified solid nickel carbonate, which contains 22.37% water (mass fraction).

[0017] E. Nickel carbonate slurry stage: nickel carbonate solids 10.3t / h after belt filter, 63.6kg / h after filter press, 21.9kg / h after precision filtration, uniformly discharged to slurry tank, liquid-to-solid ratio 6.5-6.8:1, and 46.74m 3 / h nickel electrolysis production line produces anolyte, 2.6m 3 / h with filter washing water and 15.55m 3 / h new water is fully mixed and slurried and then sent to the acid dissolution lead removal process for use.

[0018] In this embodiment, the nickel electrolysis anode liquid, sodium carbonate solution and the final discharged nickel carbonate supernatant liquid used to produce nickel carbonate were tested and analyzed, and the specific component contents are shown in Table 1.

[0019] Example 2 A. Preparation reaction stage: The nickel electrolysis anolyte and sodium carbonate solution are passed into the reaction tank for reaction. The nickel electrolysis anolyte and sodium carbonate solution are continuously reacted in six reaction tanks 1# to 6#. The anolyte produced by the nickel electrolysis production line is 20.7m 3 / h, nickel content 61.33g / L, sodium carbonate solution 13.9m 3 / h, sodium carbonate content 146.42g / L, pH 7.4 at the outlet of reaction tank 1#, temperature of reaction tanks 1#-6# 78-83℃, reaction time 5h, pH 7.8 at the outlet of reaction tank 6#, 34.22m 3 / h nickel carbonate slurry is transported to the thickening separation stage. The temperature in each reaction tank is interlocked with the steam valve, and the pH meter at the outlet of the 1# reaction tank is interlocked with the sodium carbonate solution flow meter to ensure the stable control of the temperature and pH in the preparation reaction stage.

[0020] B. Dense separation stage: nickel carbonate slurry flows at a flow rate of 34.22m 3 / h enters the thickener for thickening separation, and the flow rate of nickel carbonate supernatant is 19.14m 3 / h, pH 8.1, discharged to the fine filtration stage. The flow rate of nickel carbonate slurry in the thickener bottom flow is 14.68m 3 / h, and transported to the belt filtration separation stage.

[0021] C. Precision filtration stage: The supernatant separated from the thickener is first sent to the filter press for liquid-solid separation. The clear liquid after filter press separation is sent to the precision filter for deep filtration. The clear liquid flow rate after filtration is 18.96m 3 / h, the nickel carbonate supernatant after deep filtration contains 0.011g / L nickel, which meets the production requirements and is discharged to the wastewater treatment station. The filter residues produced by the filter press and precision filter are the purified nickel carbonate, which are uniformly sent to the nickel carbonate slurry stage.

[0022] D. Belt filtration separation stage: 14.68m3 of underflow slurry separated from the thickener 3 / h, and transported to the belt filter for liquid-solid separation. The filtrate from the belt filter is sent to the precision filtration section for deep filtration. The filter residue from the belt filter is about 11.2t of purified solid nickel carbonate with a water content (mass fraction) of 21.64%, which is sent to the nickel carbonate slurry stage.

[0023] E. Nickel carbonate slurry stage: 11.2t solid nickel carbonate filtered by belt filter, 11.2t / h solid nickel carbonate filtered by belt filter, 66.4.6kg / h solid nickel carbonate filtered by filter press, 22.7kg / h solid nickel carbonate filtered by precision filtration, uniformly discharged to slurry tank, liquid-to-solid ratio 6.5-6.8:1, and 50.25m 3 / h nickel electrolysis production line produces anolyte, 2.4m 3 / h with filter washing water and 20.15m 3 / h new water is fully mixed and slurried and then sent to the acid dissolution lead removal process for use.

[0024] In this embodiment, the nickel electrolysis anode liquid, sodium carbonate solution and the final discharged nickel carbonate supernatant liquid used to produce nickel carbonate were tested and analyzed, and the specific component contents are shown in Table 2.

[0025] Example 3 A. Preparation reaction stage: The nickel electrolysis anolyte and sodium carbonate solution are passed into the reaction tank for reaction. The nickel electrolysis anolyte and sodium carbonate solution are continuously reacted in six reaction tanks 1# to 6#. The anolyte produced by the nickel electrolysis production line is 18.66m 3 / h, nickel content 62.29g / L, sodium carbonate solution reaction 12.41m 3 / h, sodium carbonate content 149.33g / L, pH 7.3 at the outlet of 1# reaction tank, temperature of 1#-6# reaction tanks 76-81℃, reaction time 5h, pH 7.7 at the outlet of 6# reaction tank, 30.52m 3 / h nickel carbonate slurry is transported to the dense separation stage.

[0026] B. Dense separation stage: 30.52m 3 / h nickel carbonate slurry enters the thickener for thickening separation, and the flow rate of nickel carbonate supernatant is 17.86m 3 / h, pH is 8.3, and discharged to the precision filtration stage. The flow rate of nickel carbonate slurry in the thickener bottom flow is 12.09m 3 / h, and transported to the belt filtration separation stage.

[0027] C. Precision filtration stage: The supernatant separated from the thickener is first sent to the filter press for liquid-solid separation. The clear liquid after filter press separation is sent to the precision filter for deep filtration. The flow rate of the clear liquid after filtration is 17.75m 3 / h, the nickel carbonate supernatant after deep filtration contains 0.016g / L nickel, which meets the production requirements and is discharged to the wastewater treatment station. The filter residues produced by the filter press and precision filter are the purified nickel carbonate, which are uniformly sent to the nickel carbonate slurry stage.

[0028] D. Belt filtration separation stage: 12.09m3 of underflow slurry separated from the thickener 3 / h, and transported to the belt filter for liquid-solid separation. The filtrate from the belt filter is sent to the precision filtration section for deep filtration. The filter residue from the belt filter is about 9.4t of solid nickel carbonate with a water content (mass fraction) of 21.64%, which is sent to the nickel carbonate slurry stage.

[0029] E. Nickel carbonate slurry stage: nickel carbonate solids after filtering with filter are 9.4t / h, nickel carbonate solids after filtering with filter press are 59.3kg / h, and nickel carbonate solids after precision filtering are 19.2kg / h, which are uniformly discharged to the slurry tank, with a liquid-to-solid ratio of 6.5-6.8:1, and 43.41m 3 / h nickel electrolysis production line produces anolyte, 2.5m 3 / h with filter washing water and 18.01m 3 / h new water is fully mixed and slurried and then sent to the acid dissolution lead removal process for use.

[0030] In this embodiment, the nickel electrolysis anode liquid, sodium carbonate solution and the final discharged nickel carbonate supernatant liquid used to produce nickel carbonate were tested and analyzed, and the specific component contents are shown in Table 3.

[0031]

Claims

1. A continuous preparation process of nickel carbonate in a nickel electrolytic refining production system, comprising the following steps: A. Preparation reaction stage: The nickel electrolytic anolyte and sodium carbonate solution produced in the nickel electrolytic refining production system are introduced into the reaction tank for reaction at a temperature of 75-85°C for a reaction time of 4-5 hours, and the produced nickel carbonate slurry is transported to the thickening separation stage; B. Thickening and separation stage: The nickel carbonate slurry is transported to the thickener for preliminary thickening and separation. The supernatant is a sodium sulfate solution, which is discharged to the precision filtration stage. The underflow slurry of the thickener is the nickel carbonate slurry, which is transported to the belt filtration separation stage; C. Precision filtration stage: the supernatant separated from the thickener is first sent to the filter press for liquid-solid separation, and the clear liquid after filter press separation is sent to the precision filter for deep filtration; the filter residues produced by the filter press and the precision filter are purified nickel carbonate; D. Belt filter separation stage: The underflow slurry separated from the thickener is transported to the belt filter for liquid-solid separation, and the filtrate from the belt filter is sent to the precision filtration section for deep filtration. The filter residue from the belt filter is the purified solid nickel carbonate.

2. The continuous preparation process of nickel carbonate in the nickel electrolytic refining production system according to claim 1, characterized in that: In the preparation reaction stage of step A, the nickel content of the nickel electrolysis anode liquid is 55-65 g / L; the sodium carbonate content of the sodium carbonate solution is 140-150 g / L.

3. The continuous preparation process of nickel carbonate in the nickel electrolytic refining production system according to claim 1, characterized in that: In the preparation reaction stage of step A, the nickel electrolytic anolyte and the sodium carbonate solution are continuously reacted in six reaction tanks 1# to 6#, the outlet pH of the 1# reaction tank is 7.0-7.5, and the outlet terminal pH of the 6# reaction tank is 7.5-7.

8.

4. The continuous preparation process of nickel carbonate in the nickel electrolytic refining production system according to claim 1, characterized in that: In the preparation reaction stage of step A, the flow rate of producing nickel carbonate slurry is 30-35m 3 / h.

5. The process for continuous preparation of nickel carbonate in a nickel electrolytic refining production system according to claim 1, characterized in that: In the thickening and separation stage of step B, the thickener is Φ18000mm in size and has a settling area of ​​254m 2 / tower.

6. The continuous preparation process of nickel carbonate in the nickel electrolytic refining production system according to claim 1, characterized in that: In the precision filtration stage of step C, a filter press and a precision filter are used to deeply filter the nickel carbonate supernatant to ensure that the nickel content of the nickel carbonate supernatant is less than 0.025 g / L.

7. The continuous preparation process of nickel carbonate in the nickel electrolytic refining production system according to claim 1, characterized in that: In the belt filtration separation stage of step D, the water content of the solid nickel carbonate after filtering by the belt filter is 20-25%.

8. The process for continuous preparation of nickel carbonate in a nickel electrolytic refining production system according to claim 1, characterized in that: The purified nickel carbonate produced in step C and step D is discharged into a slurry tank, and is stirred and mixed evenly with new water and the anode liquid produced by the nickel electrolysis production line to prepare nickel carbonate slurry, which is then sent to the acid dissolution lead removal process for use.

Images