Batteries must always be drained before they enter the recycling process. They should only be drained to a purpose built effluent treatment plant so that the acid can be treated and neutralized. Next the batteries are broken in a hammer mill or another type of crushing machine. Manual battery breaking should be avoided due to the health and safety risks associated with this practice. From: http://www.berzelius.de/ecobat/rp/
The materials from the breaking process are placed in a tank of water, where the dissimilar densities of the materials result in some components to sink quickly (lead), some to float (plastic) and liquids to go into solution (battery acid). From here, the materials are separated and treated individually. The plastic is cleaned and transported to a plastic recycler. The acid is neutralized.
The battery scrap obtained from the breaking process is a mixture of several substances: metallic lead, lead oxide, lead sulphate and other metals such as calcium, copper, antimony, arsenic, tin and sometimes silver. In order to isolate the metallic lead from this mixture, these materials are charged into a furnace together with appropriate fluxes & reluctant, drowses, returning slugs and process dusts for smelting. Off-gases from the smelting furnace are filtered and the dust collected is returned to the furnace. The metal tapped from the kiln is transferred to refining process and treated to produce commercial quality lead. From: http://www.berzelius.de/ecobat/rp/
As a smelting plant
Bibliography: Batteries common wastes and materials USA. 2013. 09 August.