Aluminous slag prodn. in rotary furnace - with carbon addn. at furnace inlet to reduce carbon loss in off gas

摘要

Prodn. of aluminous slag comprises redn. with carbon in a rotary furnace of Al-contg. material mixed with limestone or limestone matl. two-stage countercurrent preheating of the raw material with hot gases being employed. The improvement is that the amt. of carbon required for redn. is added at the rotary furnace inlet, opt. separately from the material coming from the preheaters. Redn. is initiated immediately at the point of carbon addn. so that redn. efficiency is improved and carbon loss in the off-gas is reduced.