Method for recovery of zinc and lead from electric furnace steelmaking dusts.
Higley-LW Jr.; Fukubayashi-HH
Proc 4th Miner Waste Utilization Symp Chicago Illinois, 1974 May; :295-302
About 1 to 2 pct of the charge to the electric steel furnace finds its way up the stack and is collected as particulate matter. The dust is rich in zinc, but there is no economic technology to recover this zinc and recycle the iron residue. Disposal is a problem because the dust easily becomes airborne. The Bureau of Mines conducted laboratory research to develop a pyrometallurgical process for the recovery of zinc and lead from electric furnace steelmaking dust (25 pct zn, 2.5 pct pb). Tests on both powdered and pelletized flue dust were made in a quartz tube, electrically heated in the temperature range 1,050 deg. to 1,150 deg. C. The dust was mixed with carbon and heated in an oxygen-free atmosphere. Ninety-nine pct of the zinc could be recovered, as a prime western grade, with only a single roast reduction treatment. By preroasting the dust in air, 90 pct of the lead was recovered as pbo, and 98 pct of the zinc was subsequently removed by roast-reduction. The offgas, carbon monoxide, was burned. Further study indicated that this method could be successfully applied to other zinc-bearing dusts and slags. The process has been scaled up successfully to 25-lb batches and seems to be adaptable to continuous operation.
Proc. 4th Miner. Waste Utilization Symp., Chicago, Illinois, May 7-8, 1974, PP. 295-302