Selective separation of manganese from waste liquid containing chlorides of copper, manganese, zinc and cobalt by ammonia method

Selective separation of a variety of metal ions (copper, manganese, cobalt, zinc) from the waste liquid containing chlorides of copper, manganese, zinc and cobalt, that was the separation of manganese ions from other ions, was made to explore the optimal experimental conditions initially. Under the condition of 25 ℃, copper, zinc and cobalt ions could form the complexation ions with ammonia remaining in the solution by adding the ammonia excessively, then manganese ions could form the hydroxide precipitate in the process of experiment. The experimental results show that the optimal separation conditions are as following: at the temperature of 25 ℃, the concentration of NH₃·H₂O added is 7 mol/L, end pH value of waste liquid is 9.6 to 9.7 and the reaction time is 1 h. At the above optimal conditions, the precipitation rate of Mn ²⁺ is more than 90 %, precipitation rates of Cu²⁺, Zn²⁺ and Co²⁺ are less than 10 %, the initial separation of Mn ²⁺ and Cu²⁺, Zn²⁺, Co²⁺ is achieved.