Calcium Oxide (quicklime) and calcium hydroxide are the most commonly used industrial compounds for treating acidic waste streams and scrubbing contaminants such as sulfur from gas streams. Many chemical and industrial processes such as power production generate sulfur in the flue gas stream. Quicklime is used in its hydrogenated form as a spray to remove sulfur by the creation of sulfur dioxide in the flue gas desulfurization process. Calcium Hydroxide is also used in the neutralization of acidic waste streams. These processes create a sediment, sludge, or slurry that is difficult to dispose of or reuse in that form. Vulcan® Drying Systems has successfully treated such waste products in its drying systems.
Vulcan® Drying Systems' Gypsum Dryer Systems are designed to reduce the moisture content in this waste through a direct fired rotary dryer. Particulate matter emissions (dust) are controlled using a high-efficiency cyclone and pulse jet baghouse. A Vulcan® Drying Systems Gypsum Dryer System includes a material feed system which in some cases may include a shredder, pug mill or other material preparation piece to allow for pretreatment of the waste to classify it and eliminate clumping or balling of dried material.
In the process, wet material is fed to a high slip-lined hopper, which feeds a material classifier. Once prepped, the material is gravity fed to a belt conveyor and then a final conveyor which transports the material into the drum.