Fundamental aspects of recycling of nickel–cadmium batteries through vacuum distillation

In spite of the existence of several NiCd batteries treatment processes around the world, little is known about the fundamental aspects of this technology. The objective of this research is to study the most important technological variables of NiCd batteries recycling by vacuum distillation. Laboratory equipment was set up to study vacuum thermal processing of milled batteries. During the tests, the total pressure was maintained at 0.1 mbar while temperatures varied from 700 to 1100 °C. Results obtained show that the distillation process is possible at temperatures above 700 °C. If temperature is raised to the range of 900–1100 °C, treatment time is reduced to less than 2 h. At temperatures higher than 900 °C the recovery of Cd contained in the batteries reached 99.9%.