Ferric chloride leach-electrolysis process for production of lead

The U.S. Department of the Interior, Bureau of Mines, under a cost-sharing, cooperative research agreement with lead producers, is studying a process to eliminate sulfur oxide generation and to minimize lead emission in the production of lead. The new process consists of leaching lead sulfide concentrate with a ferric chloride-sodium chloride solution to produce lead chloride, and fused-salt electrolysis of lead chloride to produce lead metal and chlorine. The chlorine is used to regenerate ferric chloride in the leach solution. The study is being conducted in a process investigation unit which treats 750 lb of concentrate a day. This paper discusses the results of operation of the process investigation unit, data on lead monitoring, and the precautions employed to control lead levels in the workplace atmosphere. The monitoring data for the initial phase of the investigation show lead levels well within OSHA permissible exposure limits. Continued development is necessary before the process can be considered for implementation.