Combining forces
Upgrading cement grinding systems offers both process and commercial benefits. The use of a high-pressure grinding roll in semi-finish grinding mode significantly reduces specific energy consumption and improves production capacity. But this type of grinding system requires two types of air classifiers, which usually ties up additional investment and space. Therefore, Germany-based Maschinenfabrik Köppern has developed a compact air classifier that enables grinding system upgrades by integrating only one combined machine. By Florian Kleemann, Köppern Aufbereitungstechnik GmbH & Co KG, Germany.
Figure 1: conventional cement grinding with high-pressure gridning roll (HPGR) in semi-finish mode:
1 - HPGR, 2 - static cascade air classifier, 3 - dynamic air classifier and 4 - ball mill
High-pressure grinding rolls (HPGR) have been used in cement production for more than 30 years. Since the first industrial application for comminution in 1985, these highly-efficient machines have gained in importance with their main applications in the grinding of brittle materials.1 HPGRs were often added upstream to existing cement plants with a ball mill and an air classifier in closed-circuit grinding. This pre-grinding, which partially moves the grinding load from the ball mill into the HPGR, results in savings of specific energy of around 20 per cent compared to simple closed-circuit ball mill (CCBM) grinding.2
