Blast-Furnace-Gas Cleaning for Iron and Ferromanganese Production

Abstract

A process for removing the superfine smokes from ferromanganese blast-furnace gases having low investment and low operating cost is described. This method solves both the air and stream-pollution problems. The ferro blast-furnace gas is cleaned from 10 to 15 grains per cu ft to less than 0.01 grains per cu ft by a wet-washing procedure in a Pease Anthony venturi scrubber. The alkali cyanide stream-pollution problem is solved by the control of pH and complete recycle of the liquors so that the cyanide is stripped by the incoming gas and is subsequently burnt in the stoves or boilerhouse. The liquor is separated from solids in a Dorr thickener. The solids are removed in the underflow as a thick slurry which is either returned to the furnace or dumped in a pit in the ore yard. The overflow is pumped back to the venturi. The chemistry and physical equipment of the process are described.