The rotary drum dryer is improved energy-efficient products on the basis of the single cylinder rotary dryer. The number of enterprises, the application of a variety of industries, and achieved good results. Rotary drum dryer improved the original monocular monocular dryer internal structure, increase the wet material into the machine to drying and to extend the drying time of wet material in the machine, coupled with the seal, moisture and reasonable supporting measures, the production capacity of the dryer with the original single cylinder dryer compared to 50-80% increase in unit volume of evaporation intensity up 120-180kg/m3, standard coal consumption is only 6-8kg / t. Its advanced technology and reasonable operating parameters, the operation is simple and feasible. Can be used widely used in various sectors of the slag, clay, coal, iron ore and other mixed materials, raw materials, drying of dry-mixed mortar, sand and other construction as well as chemical, foundry and other industries.