Abstract: Calcium carbide is an important basic chemical raw material for the production of
PVC, lime nitrogen，acetylene gas and other products. About 50 million tons of calcium carbide
slag are produced every year，in order to promote the transformation from“resources-productsemissions”
model to“resources-products-renewable resources” model，reduce the consumption
of limestone ore and achieve the double carbon target. This paper introduces in detail a kind of
energy-saving and environment-friendly circulating suspension calcination technology of calcium
carbide slag, which can produce active lime as well as medium-speed lime through the adjustment
of circulating ratio，so that the value of circulating utilization of calcium carbide slag can be
greatly increased，and the system energy consumption is low，environmental protection，stable
and reliable operation.

Key words: Carbide slag, Suspension calcination, Medium-speed lime, Production technology