Method for producing seed crystal of cobalt powder

Abstract

Provided is a method for producing seed crystals of cobalt powder, sequentially including: a complexing step of adding ammonia, an ammonia compound solution, or both of ammonia and an ammonia compound solution to a cobalt sulfate solution to obtain a solution containing a cobalt ammine sulfate complex; a mixing step of adding a solid to the solution containing the cobalt ammine sulfate complex to form a mixture slurry; a reduction and precipitation step of charging a reaction vessel with the mixture slurry, blowing hydrogen gas into the reaction vessel and reducing cobalt contained in the mixture slurry to obtain a cobalt powder slurry containing cobalt precipitate with a cobalt component precipitated on the surface of the solid as cobalt powder; and a solid-liquid separation step of performing solid-liquid separation on the cobalt powder slurry to obtain cobalt precipitate and a solution after reduction.

1 . A method of producing seed crystals of cobalt powder, sequentially comprising:
 a complexing step of adding ammonia, an ammonia compound solution, or both of ammonia and an ammonia compound solution to a cobalt sulfate solution to obtain a solution containing a cobalt ammine sulfate complex;   a mixing step of adding nickel powder as a solid that is insoluble or slightly soluble in the solution containing the cobalt ammine sulfate complex, to the solution containing the cobalt ammine sulfate complex obtained in the complexing step to form a mixture slurry;   a reduction and precipitation step of charging a reaction vessel with the mixture slurry obtained in the mixing step, and blowing hydrogen gas into the reaction vessel to reduce cobalt contained in the mixture slurry and obtain a cobalt powder slurry containing cobalt precipitate with a cobalt component precipitated on a surface of the solid as cobalt powder; and   a solid-liquid separation step having   a solid-liquid separation treatment for separating the cobalt powder slurry obtained into the cobalt precipitate and a solution after reduction, and a solid separation treatment for separating the cobalt precipitate obtained into the nickel powder of the solid added and the cobalt powder that is precipitated on the surface of the nickel powder of the solid, to form the solution after reduction, the nickel powder of the solid, and the cobalt powder.   
     
     
         2 . The method of producing seed crystals of cobalt powder according to  claim 1 ,
 wherein the nickel powder of the solid has an average particle size of 0.1 to 5 μm.   
     
     
         3 . The method of producing seed crystals of cobalt powder according to  claim 2 , wherein a cobalt concentration in the solution containing the cobalt ammine sulfate complex is 75 g/L or less. 
     
     
         4 - 5 . (canceled) 
     
     
         6 . The method of producing seed crystals of cobalt powder according to  claim 1 , wherein a cobalt concentration in the solution containing the cobalt ammine sulfate complex is 75 g/L or less.