The present invention relates to a process for the purification of Manganese sulfate monohydrate (1). The present invention also specifically relates to a cost-effective process for the preparation of pharmaceutical grade Manganese sulfate monohydrate (1) having purity greater than 99.9998% (w/w).

In a method for recovering an active metal of a lithium secondary battery, a sulfuric acid solution is added to a lithium metal composite oxide so as to prepare a sulfated active material solution. A transition metal is extracted from the sulfated active material solution. A lithium precursor is recovered by adding a lithium extracting agent to the solution remaining after the transition metal has been extracted from the sulfated active material solution. In the method, the amount of impurities is reduced, and sulfuric acid and the neutralizing agent can be recycled so that a high-yield lithium precursor recovery is enabled.

A process and method for producing a crystallized metal sulfate. The crystallized metal sulfate may be battery-grade. The method may comprise receiving a metal ion-containing stream and crystalizing a metal sulfate from the stream. The process may comprise receiving a stream from a metal processing plant, and crystalizing a metal sulfate from the stream. The process may be a metal electrowinning process comprising crystalizing a metal ion-containing stream to form a crystallized metal sulfate in a mother liquor. The process or method may comprise returning the mother liquor upstream or to the metal electrowinning process.

A process and method for producing a crystallized metal sulfate. The crystallized metal sulfate may be battery-grade. The method may comprise receiving a metal ion-containing stream and crystalizing a metal sulfate from the stream. The process may comprise receiving a stream from a metal processing plant, and crystalizing a metal sulfate from the stream. The process may be a metal electrowinning process comprising crystalizing a metal ion-containing stream to form a crystallized metal sulfate in a mother liquor. The process or method may comprise returning the mother liquor upstream or to the metal electrowinning process.