... medium-hard bulk materials. Double roll crusher1,Easy Maintenance; 2,Low Cost;3,Stable Operation 4,Adjustable Output Size ... . 1:6.Feed materials: limestone, gypsum, coal, coke, different types of ore. Sand, Coal, building materials, stone factory, chemeical industry, ... rollers to rotate in the opposite directions. When double roller crusher works, materials fall into the gap between rollers through ...