Chlorine water treatment method for producing cobalt through electrodeposition of chlorination system

Abstract

The invention discloses a chlorine water treatment method for producing cobalt through electrodeposition of a chlorination system, and mainly relates to a treatment method for chlorine water generated in the process of evaporating and concentrating electrolyte through cobalt electrodeposition of the chlorination system. Hydrogen peroxide is added into cobalt-containing chlorine water generated in the electro-deposition cobalt production process for dechlorination, and then the cobalt-containing chlorine water is returned to the reverse extraction operation in the P507 nickel-cobalt separation process of the extraction procedure. According to the acidity and cobalt content of the chlorine water, reverse extraction acid is prepared, and a cobalt chloride solution with the cobalt content larger than 130 g / L is finally produced. And meanwhile, the cobalt-containing chlorine water in the production process of the electrodeposited cobalt is recycled.

Description

Technical Field

[0001] The invention relates to the technical field of nonferrous hydrometallurgical processes, in particular to a method for treating chlorine water in the production of cobalt by electrowinning in a chlorination system. Background Art

[0002] The use of the chlorination system insoluble anode electrowinning process can obtain a higher quality electrowinning cobalt product (see CN202411259709.3). The main process is to produce a qualified cobalt chloride solution after the cobalt-containing raw material is pulped, dissolved, iron-removed, P204 extracted and impurities removed, and P507 extracted and separated nickel and cobalt. After the cobalt chloride solution is deeply purified to remove impurities such as As, Cd, and Cu, it is mixed with the anode liquid and cathode liquid of the electrowinning system, and then filtered by a filter press before entering the electrolytic cell for electrowinning. In the electrolytic cell, the starting plate is used as the cathode and the titanium mesh coated with ruthenium on the surface is used as the anode. Under the action of direct current, the cathode produces an electrolytic cobalt product, and chlorine gas is precipitated on the anode. The anode liquid is dechlorinated and evaporated, mixed with the cathode liquid, and returned to the new liquid for preparation, which is filtered and recycled. During the electrowinning process, a high-concentration cobalt chloride solution needs to be continuously added to maintain the cobalt concentration of the electrolyte in the electrolytic cell at 60-70g / l. In order to maintain the balance of the electrolytic system and improve the environment of the electrolytic plant, the anolyte needs to be evaporated, concentrated and dechlorinated. A large amount of chlorine water will be produced during the evaporation and concentration process. Since chlorine water has a pungent smell and contains trace amounts of cobalt (cobalt content is 0.2-1g / l), it is difficult to recycle it. Usually, the chlorine water is adjusted to pH 6-7 with alkali, and then it is discharged after being deweighted by an ion exchange column. However, this treatment method will increase the production cost of electrolytic cobalt, and at the same time, it will cause a large amount of wastewater to be discharged, which does not meet the goal of zero discharge of environmentally friendly wastewater. Summary of the invention

[0003] The object of the present invention is to provide a chlorine water treatment method for producing cobalt by electrowinning in a chlorination system, which can effectively reduce the amount of chlorine water discharged, recycle the cobalt content of chlorine water, and reduce production costs in response to the problems existing in the above-mentioned technologies.

[0004] A method for treating chlorine water in the electrolytic production of cobalt by chlorination system is to dechlorinate the chlorine water in the electrolytic production of cobalt and return it to the extraction process for preparing stripping acid. The dechlorination of the chlorine water adopts hydrogen peroxide as a dechlorinating agent, and the amount of hydrogen peroxide added during the dechlorination process is controlled so that the free chlorine in the water after dechlorination is less than 0.003g / L. The operation of preparing stripping acid is to control the ratio of dechlorinated chlorine water and hydrochloric acid so that the acidity of the prepared stripping acid is controlled at 4.5-5mol / L and the cobalt content is 0.1-1g / L; when the prepared stripping acid is used to strip the organic matter loaded with cobalt in P507, the cobalt loaded in the organic matter and the cobalt in the stripping acid are stripped into the cobalt chloride solution together, so that the cobalt in the chlorine water is recycled.

[0005] The invention discloses a chlorine water treatment method for producing cobalt by electrowinning in a chlorination system. The process flow is simple, the chlorine water discharge volume can be effectively reduced, and the chlorine water can be fully recycled to achieve the goal of zero wastewater discharge. Meanwhile, the chlorine water can be used to prepare stripping acid so that the cobalt content in the chlorine water can be recycled, thereby reducing the production cost of electrowinning cobalt. DETAILED DESCRIPTION

[0006] The present invention is further explained below in conjunction with specific implementation modes.

[0007] A method for treating chlorine water for producing cobalt by electrowinning in a chlorination system, wherein the amount of hydrogen peroxide added can be controlled to reduce the free chlorine content in the chlorine water to below 0.003 g / L, and the chlorine water after dechlorination has no irritating odor. By controlling the ratio of chlorine water and refined hydrochloric acid, the hydrogen ion concentration of the stripping acid is made 4.5-5 mol / L, and when the prepared stripping acid is used to strip the organic matter loaded with cobalt in P507, the cobalt loaded in the organic matter and the cobalt in the stripping acid are stripped into a cobalt chloride solution together, thereby realizing the recovery of cobalt.

[0008] Specifically, the chlorine water used for electrolytic production of cobalt is reduced from 0.5g / L before dechlorination to 0.003g / L by adding hydrogen peroxide, and the chlorine water after dechlorination has no irritating odor; after dechlorination, the chlorine water is returned to the stripping operation of nickel-cobalt separation in the extraction process P507, and the ratio of chlorine water and refined hydrochloric acid is controlled to make the hydrogen ion concentration of the stripping acid 4.5-5mol / L. When the P507 cobalt-loaded organic is stripped with the configured stripping acid, the cobalt loaded in the organic is stripped into the cobalt chloride solution together with the cobalt in the stripping acid, wherein the cobalt concentration of the cobalt chloride solution can reach more than 130g / L.

Claims

1. A method for treating chlorine water in the production of cobalt by electrowinning in a chlorination system, characterized in that: It is an operation to dechlorinate the chlorine water in the electrolytic cobalt production process and return it to the extraction process to prepare stripping acid.

2. A method for treating chlorine water for producing cobalt by electrowinning in a chlorination system as claimed in claim 1, characterized in that: The chlorine water dechlorination adopts hydrogen peroxide as a dechlorinating agent, and the amount of hydrogen peroxide added is controlled during the dechlorination process so that the free chlorine in the water after dechlorination is less than 0.003g / L.

3. A method for treating chlorine water for producing cobalt by electrowinning in a chlorination system as claimed in claim 1, characterized in that: The operation of preparing the stripping acid is to control the ratio of dechlorinated chlorinated water and hydrochloric acid so that the acidity of the prepared stripping acid is controlled at 4.5-5 mol / L and the cobalt content is controlled at 0.1-1 g / L; when the prepared stripping acid is used to strip the organic matter loaded with cobalt in P507, the cobalt loaded in the organic matter and the cobalt in the stripping acid are stripped into the cobalt chloride solution together, so that the cobalt in the chlorinated water is recovered and utilized.