Abstract:In production practice of cobalt chloride closed electrowinning, technical study, equipment optimization and modification of automatic control system were carried out to solve the problems existing in operation of chlorine gas absorption by-product sodium hypochlorite. Through experiment of influence of gas inlet temperature, absorption temperature and concentration of residual alkali of absorption solution on chlorine gas absorption, control condition and relationship between pH value of absorption end point and redox potential and eletroconductivity were determined. Absorption temperature automatic control system and combined monitoring system of pH value, redox potential and eletroconductivity of absorption end point were installed, which can effectively improve operation stability of chlorine absorption system and ensure product quality of sodium hypochlorite. After transformation, absorption system runs stably, quality of sodium hypochlorite is obviously improved. Product quality of sodium hypochlorite is improved obviously, mass fraction of available chlorine is 12%—14%, sodium hydroxide is 0.6%—1.0%, and liquid alkali (32%) consumption per ton of cobalt reduces by 260 kg after transformation. Production cost reduces effectively, and economic benefit and market competitiveness of enterprise is improved.