Optimizing rotary furnace smelting of battery residue

The process for recovering lead from battery residues used in several Mexican Plants include lead blast furnace and rotary furnaces. The formers are basically fed with recycled batteries together with the necessary additives to produce metallic lead. One of the by-products generated in the blast furnace is a dust mainly formed by lead sulfide. The rotary furnace is used to recover lead from lead batteries, dross from the refining-alloying process and the leady fines produced in the blast furnace. This paper describes thermodynamic analysis made to the rotary furnace process to understand the effect that each component of the system has upon the lead recovery. In order to enhance the process, the influence of iron chips composition and excess coke on slag viscosity is discussed. A computer optimization program has been developed to design the furnace charge based on material and energy balances, together with the thermodynamic equilibrium calculation.