High purity cobalt chloride and manufacturing method therefor

Abstract

A high purity cobalt chloride having a purity of 5N (99.999%) or higher and a manufacturing method of the high purity cobalt chloride via electrolysis are provided. In the method, cobalt having a purity of 5N or higher is used as an anode, a diluted hydrochloric acid bath having a pH of 1.5 to 3.0 is used as an electrolytic solution, the cobalt anode and a cathode plate are partitioned with an anion exchange membrane, and electrodeposition of the cobalt onto the cathode plate is thereby inhibited. The manufacturing method is capable of providing high purity cobalt chloride at a higher purity and at a lower production cost than conventional methods. Under circumstances where demands for cobalt chloride may increase, cobalt chloride needs to be manufactured at high volume and at low cost, and the method disclosed herein provides a technique capable of satisfying the foregoing requirements.

I claim: 
     
         1 . A manufacturing method of high purity cobalt chloride via electrolysis, wherein cobalt having a purity of 5N (99.999%) or higher is used as an anode, a diluted hydrochloric acid bath having a pH of 1.5 to 3.0 is used as an electrolytic solution, the cobalt anode and a cathode plate are partitioned with an anion exchange membrane, and electrodeposition of the cobalt which became eluted into the hydrochloric acid bath onto the cathode plate is thereby inhibited. 
     
     
         2 . The manufacturing method of high purity cobalt chloride via electrolysis according to  claim 1 , wherein the cobalt, and chlorine in the electrolytic solution, are subject to electrosynthesis, and so as to adjust the diluted hydrochloric acid concentration which decreases during progress of the electrosynthesis reaction, a new diluted hydrochloric acid solution is added to an electrolytic bath for use in the electrosynthesis, or a catholyte circulation tank is provided separately from the electrolytic bath for use in the electrosynthesis, a new diluted hydrochloric acid solution is filled in the catholyte circulation tank and circulated and supplied to the electrolytic bath, and the electrosynthesis is performed while adjusting a pH value of the electrolytic solution to 1.5 to 3.0. 
     
     
         3 . The manufacturing method of high purity cobalt chloride via electrolysis according to  claim 2 , wherein a Ti plate is used as the cathode plate. 
     
     
         4 . The manufacturing method of high purity cobalt chloride via electrolysis according to  claim 3 , wherein the thus prepared cobalt chloride solution is evaporated to dryness and concentrated, thereafter removed, filtered and separated, and the filtered cobalt chloride is subsequently dried. 
     
     
         5 . The manufacturing method of high purity cobalt chloride via electrolysis according to  claim 4 , wherein, upon evaporating the cobalt chloride solution to dryness, the evaporation to dryness process is ended at the time that the weight of the cobalt chloride solution reaches 80 to 95% of the weight before evaporation to dryness, the concentrated cobalt chloride solution is removed, filtered and separated, and the filtered cobalt chloride is subsequently dried. 
     
     
         6 . The manufacturing method of high purity cobalt chloride via electrolysis according to  claim 5 , wherein the filtered cobalt chloride has a purity of 99.999% (5N) or higher excluding gas components of O, C, N, H, S, and P, and a content of Tl as an impurity element of 1 ppm or less. 
     
     
         7 . The manufacturing method of high purity cobalt chloride via electrolysis according to  claim 2 , wherein the thus prepared cobalt chloride solution is evaporated to dryness and concentrated, thereafter removed, filtered and separated, and the filtered cobalt chloride is subsequently dried. 
     
     
         8 . The manufacturing method of high purity cobalt chloride via electrolysis according to  claim 7 , wherein, upon evaporating the cobalt chloride solution to dryness, the evaporation to dryness process is ended at the time that the weight of the cobalt chloride solution reaches 80 to 95% of the weight before evaporation to dryness, the concentrated cobalt chloride solution is removed, filtered and separated, and the filtered cobalt chloride is subsequently dried. 
     
     
         9 . The manufacturing method of high purity cobalt chloride via electrolysis according to  claim 8 , wherein the filtered cobalt chloride has a purity of 99.999% (5N) or higher excluding gas components of O, C, N, H, S, and P, and a content of Tl as an impurity element of 1 ppm or less. 
     
     
         10 . The manufacturing method of high purity cobalt chloride via electrolysis according to  claim 1 , wherein a Ti plate is used as the cathode plate. 
     
     
         11 . The manufacturing method of high purity cobalt chloride via electrolysis according to  claim 11 , wherein the thus prepared cobalt chloride solution is evaporated to dryness and concentrated, thereafter removed, filtered and separated, and the filtered cobalt chloride is subsequently dried. 
     
     
         12 . The manufacturing method of high purity cobalt chloride via electrolysis according to  claim 11 , wherein, upon evaporating the cobalt chloride solution to dryness, the evaporation to dryness process is ended at the time that the weight of the cobalt chloride solution reaches 80 to 95% of the weight before evaporation to dryness, the concentrated cobalt chloride solution is removed, filtered and separated, and the filtered cobalt chloride is subsequently dried. 
     
     
         13 . The manufacturing method of high purity cobalt chloride via electrolysis according to  claim 12 , wherein the filtered cobalt chloride has a purity of 99.999% (5N) or higher excluding gas components of O, C, N, H, S, and P, and a content of Tl as an impurity element of 1 ppm or less. 
     
     
         14 . The manufacturing method of high purity cobalt chloride via electrolysis according to  claim 1 , wherein the thus prepared cobalt chloride solution is evaporated to dryness and concentrated, thereafter removed, filtered and separated, and the filtered cobalt chloride is subsequently dried. 
     
     
         15 . The manufacturing method of high purity cobalt chloride via electrolysis according to  claim 14 , wherein, upon evaporating the cobalt chloride solution to dryness, the evaporation to dryness process is ended at the time that the weight of the cobalt chloride solution reaches 80 to 95% of the weight before evaporation to dryness, the concentrated cobalt chloride solution is removed, filtered and separated, and the filtered cobalt chloride is subsequently dried. 
     
     
         16 . The manufacturing method of high purity cobalt chloride via electrolysis according to  claim 15 , wherein the filtered cobalt chloride has a purity of 99.999% (5N) or higher excluding gas components of O, C, N, H, S, and P, and a content of Tl as an impurity element of 1 ppm or less. 
     
     
         17 . The manufacturing method of high purity cobalt chloride via electrolysis according to  claim 14 , wherein the filtered cobalt chloride has a purity of 99.999% (5N) or higher excluding gas components of O, C, N, H, S, and P, and a content of Tl as an impurity element of 1 ppm or less.