The objective of this work is to study the recycling of sealed nickel–cadmium batteries through cadmium distillation using a carbonaceous material as reducing agent. In spite of the existence of some industrial processes for nickel–cadmium batteries recycling, there are few fundamental studies about this subject. For the study of the reducing process, coal was added to the material of electrodes. Reduction process was performed from 700 to 1000°C with different quantities of reducing added to the load. Results showed that cadmium purity is of approximately 99.92% and the main impurity found was zinc at around 200ppm. A Ni–Co alloy containing 100ppm cadmium was also obtained.