Use of Synthetic Gypsum

A cement plant in Knoxville, Tennessee , is using synthetic gypsum in its cement finish mill. Gypsum—synthetic or natural—controls the set time or time of hardening of the concrete. Synthetic gypsum is a by-product of the electric power industry's sulfur dioxide scrubber system. The Knoxville facility receives moist material from the power plant and mixes it with cement kiln dust, a by-product from their cement kiln system. The result is a powder that can be added to the mill grinding the clinker to produce the cement. This process allows the beneficial use of two by-products, one from the electric power industry and the second from the cement manufacturing process.