For the purpose of the efficiency improvement of the existing tube mill for finishing process, a vertical roller mill for pre-grinding of clinker is installed in the upstream of the tube mill. The structure that has the turn table and 2～4 rollers to mill clinker is basically the same as vertical roller mills for raw materials. But the roller mill for pre-grinding have no classifier and air sweep. The pre-ground clinker is discharged outside mill, and separated with vibrating screen. The coarse particles are circulated to pre-grinding system, and the fine particles are fed to finishing tube mill.
Specific power consumption in finishing process: 10%-20% reduction
Grinding capacity of finishing tube mill: 30-60% increase
This technology is related to vertical mill applied to other process.
Ministry of Economy,Trade and Industry, Japan