... heat exchange 2.Automatic temperature control system 3.Direct process High quality screw dryer Work principle:The raw material plate which is ... , natural gas, LPG gas, wood, and etcUsage:Widely used to dry yellow sand, clay, slag, flyash, , iron powder,sand in casting ... choice for the slag in the cement factories and premixed dry mortar production line.The material granular size is around 20 ...