GYPSUM CALCINATION FURNACE AND GYPSUM CALCINATION METHOD

PROBLEM TO BE SOLVED: To prevent generation of uneven calcination in calcined gypsum and reduce fuel consumption in a calcination furnace by improving fluidity of a raw material gypsum sedimentation layer in the furnace.SOLUTION: A gypsum calcination furnace (1) comprises a furnace body (3-7) including a furnace inner wall surface having a circular or annular shape in a plan view, and a combustion tube (2) arranged at a center of the furnace body. Raw material gypsum is calcined or dried by a high-temperature gas jet flow jetted from a bottom of the combustion tube. Agitators (10) are provided which penetrate a conical surface or an inner peripheral surface formed by the furnace inner wall surface. Each agitator comprises a rotary shaft (16) projecting into the furnace from the conical surface or the inner peripheral surface at a position below a top surface of the raw material gypsum having deposited in the furnace, and an agitation blade (11) rotating in a region (α) in the furnace by rotation of the rotary shaft. A rotation center axis (X) of the rotary shaft is oriented in a direction at an angle (θ2) of 30-80 degrees in the circumferential direction of the furnace body with respect to a normal line (RL) passing through an intersection (CP) of the rotation center axis (X) and the conical surface or the inner peripheral surface to energize the raw material gypsum near the furnace inner wall surface in the circumferential direction of the furnace body.SELECTED DRAWING: Figure 2 【課題】炉内の原料石膏堆積層の流動性を改善し、焼成石膏の「焼きむら」発生を防止するとともに、焼成炉の燃料消費量を削減する。【解決手段】石膏焼成炉(1)は、平面視円形又は環状の炉内壁面を有する炉体(3-7)と、炉体の中心部に配置された燃焼管(2)とを備え、燃焼管の下部から噴出する高温ガス噴流によって炉内の原料石膏を焼成し又は乾燥させる。炉内壁面が構成する円錐面又は内周面を貫通する攪拌機(10)が設けられる。攪拌機は、炉内に堆積した原料石膏の上面よりも下方の位置において円錐面又は内周面から炉内に突出する回転軸(16)と、回転軸の回転によって炉内領域(α)で回転する攪拌翼(11)とを備える。回転軸の回転中心軸線(X)は、回転中心軸線(X)と円錐面又は内周面との交点(CP)を通る法線(RL)に対し、炉体周方向に３０〜８０度の角度（θ２）をなす方向に配向され、炉内壁面近傍の原料石膏を炉内壁面の周方向に付勢する。【選択図】図２