After the damp raw material is put into the drier from one end, it is turned over through stirring-up rake inside the cylinder and distributed uniform in the drier and contacted with countercurrent hot air fully. It speeds up heat and mass conducting of dry. During the period of dry, raw material is effected by stirring-up rake with gradient and hot air, it can be moved and passed through the dry region and to star valve and then discharge the finished product.
It is suitable for drying raw materials that have large size and heavy specific gravity. For example: ore, slag of blast furnace, coal, metallic powder, phosphorous fertilizer, ammonium sulphate and so on.
Dry powder, granule raw materials which have special requirements to drying. For example: HP vesicant, lees, light calcium carbonate, active white earth, magnetic powder, graphite, medical slag and so on.
Dry raw materials the need to dry at low temperature continuously and its batch is large.