Method for recovering sulfur dioxide from a gas stream

Thomas D. Wheelock, Iowa State University
David R. Boylan, Iowa State University

Abstract

This invention relates to the reductive decomposition of calcium sulfate, and more particularly to a procedure by which calcium sulfate is reduced to produce lime and sulfur in a readily convertible form, i.e., sulfur dioxide.

It is a general object of this invention to provide a novel procedure for the reductive decomposition of calcium sulfate, such as the naturally occurring gypsum, anhydrite or by-product gypsum-such as would be produced in the wet process production of phosphoric acid. Another object is to provide a procedure for decomposing calcium sulfate wherein the products of the reaction are provided in a commercially acceptable form. Still another object is to provide a procedure for the decomposition of calcium sulfate which is characterized by minimal formation of calcium sulfide. Yet another object is to provide the optimum conditions for a calcium sulfate decomposition when using reducing gas mixtures. Other objects and advantages of this invention can be seen as this specification proceeds.