Aqueous cobalt chloride solution purification method

Abstract

The invention provides an aqueous cobalt chloride solution purification method capable of efficiently removing impurities from a cobalt salt solution. The solution is a method for bringing metallic nickel into contact with an aqueous cobalt chloride-containing solution to remove impurities by a cementation reaction, wherein the metallic nickel is washed with an acidic solution of pH 2.5 or less prior to bringing the metallic nickel into contact with the aqueous cobalt chloride-containing solution. Since the metallic nickel is washed with an acidic solution of pH 2.5 or less, the passive film on the surface of the metallic nickel is removed. Since the passive film has been removed, when the metallic nickel is brought into contact with the aqueous cobalt chloride-containing solution, impurities that are more electropositive than metallic nickel can be precipitated by a cementation reaction. Moreover, since the metallic nickel need only be washed with acid and brought into contact with the aqueous cobalt chloride-containing solution, it is possible to remove impurities from the aqueous cobalt chloride-containing solution easily.

Description

technical field [0001] The present invention relates to the purification method of cobalt chloride aqueous solution. Background technique [0002] Cobalt is a rare metal and is a precious metal used as a material of an alloy. In addition, cobalt is also used as an electrode material for batteries for purposes other than alloys. For example, cobalt is also used as a positive electrode material of a lithium ion battery which is a non-aqueous electrolyte secondary battery for vehicles developed in recent years. [0003] When manufacturing a positive electrode material for a lithium ion battery as such a nonaqueous electrolyte secondary battery, a metal hydroxide called a precursor is generally formed by neutralizing an aqueous solution of a metal salt mixed at a prescribed ratio of. When this precursor is mixed with a lithium compound and fired, a positive electrode material can be produced. Furthermore, when producing a positive electrode material containing cobalt, a salt...

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Problems solved by technology

On the other hand, since the solubility product of copper is 2.2×10 -20 , the solubility of copper at pH6 is 14mg-copper / L, so the separation of copper becomes worse

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