REDUCED DUSTING GYPSUM COMPOSITES AND METHOD OF MAKING THEM

摘要

A composite product is made from a slurry that includes host particles having alpha-calcined calcium sulfate hemihydrate crystals formed in the voids, cracks, fissures or other surface opening of the host particle, alpha-calcined calcium sulfate hemihydrate crystals and a dust reducing agent. The dust reducing agent is at least one of a synthetic wax and soy lecithin. As the slurry cools, the hemihydrate forms an interlocking matrix of calcium sulfate dihydrate crystals, some of which are attached to host particles. A process for making the slurry includes forming a slurry of host particles and calcium sulfate dihydrate, then heating the slurry to at least 140°C and autogenous pressure until substantially all of the calcium sulfate dihydrate has been converted to alpha-calcined calcium sulfate hemihydrate. The dust reducing agent is added to the slurry. A composite panel is made by further dewatering the slurry and forming a panel.