One-step pyrolysis process for recover zinc and mercury from spent zinc-manganese batteries

In this paper, One-step pyrolysis process for the recovery of mercury and zinc from spent zinc-manganese batteries is proposed. Laboratory tests were performed to remove mercury and zinc from spent batteries and recover them. Correctitude test were used to analyze the effect of three factors: temperature, weight and time on the removing and recovery efficiency of zinc. In this research, temperature is dominant factor, weight and time are subordinate. After removing mercury, higher temperature could assure the removing efficiency of mercury above 99.9% at the same time of removing zinc. Under 0.02 MPa, efficiency of removing and recycling of zinc were investigated. The removing efficiency is 94.2% at 950 °C and 96.2% at 1000 °C. When the heated time is 1.5 h, the removing efficiency is 95.6%, which reach the aim 95.0%. With the increase of sample weight, the necessary heated time could be kept within 2.5 h without the loss of removing efficiency. The recycling efficiency of zinc could approach 75%. The content of zinc is above 99.0% in condensed zinc product. After being treated, the residue mass is about 40% of sample.