... 've designed various rotary dryers for drying slag, limestone, coal powder, clay, sawdust, oil palm fiber, grass, river stone, poultry dung, ores ... motor, cyclone dust collector, furnace and etc. 3. heating source: coal, coal gas, natural gas, LPG gas, wood, and etc. 4. Mode ... hour? d. what kind of heating source you'll use? coal, coal gas, biomass, diesel, or others? After we make clear of ...