Update on Spent Potliners Treatments: Kinetics of Cyanides Destruction at High Temperature

A review of the technologies available for treating the cyanide content of spent potliners is presented. The various strategies of treatment are compared. Processes involving the combustion of spent potliners at temperature close to 800 °C were selected as the most cost-effective approach. It was found that designers of such processes are confronted with a lack of data concerning the kinetics of cyanide destruction of spent potliners and the occurrence of agglomeration. This paper addresses both issues by showing that small amounts of additives are necessary for the smooth operation of combustion processes and by presenting a simple model for predicting the amount of additive needed in well-mixed conditions. In addition, for the first time, the apparent kinetics of the destruction of cyanides in spent potliners at high temperature is presented.