PROCESS FOR PREPARING HYDROGEN FLUORIDE BY REACTING SULPHURIC ACID WITH FLUOR SPAR IN A ROTATING FURNACE

摘要

The process comprises: a) feeding the sulfuric acid and the fluorospar to a prereaction or premixer device operating so as to produce at its exit a pulverulent product the conversion of which is from 40 to 50%; then b) introducing the said pulverulent product at a temperature of from 20 to 120 DEG C into a rotating oven operating at a temperature of from approximately 80 to 350 DEG C in which hydrofluoric acid and calcium sulphate are formed, and simultaneously c) recycling the reaction product to the oven such that from 3 to 3.5 mole of calcium sulphate are recycled per mole of calcium fluoride contained in the pulverulent product entering the oven.