High-efficiency cement grinding
For more than a quarter of a century the ThyssenKrupp Polysius’ POLYCOM® high-pressure grinding roll (HPGR) has been in successful operation. More than 65 of the presses are working in highly-efficient clinker grinding systems around the world. By using the POLYCOM as a stand-alone grinding machine (finish grinding circuit) a reduction in specific power consumption of around 50 per cent compared to conventional ball mill circuits is achievable. The high compression stressing applied inside the material bed in a HPGR is distinguished by its significantly-higher degree of energy utilisation in comparison to the frictional and impact stressing of the material being ground in a ball mill. By Dr A Haack and Dr O Hagemeier, ThyssenKrupp Polysius AG, Germany.
Figure 1: process flow sheet of a finish grinding
system with POLYCOM® and SEPOL® PC
POLYCOM works in closed circuit with SEPOL® PC the static-dynamic separator. A very compact static cross-flow separator is combined with the highly-efficient dynamic separator SEPOL® LM to the newly-established SEPOL PC.
As a result of the continuous optimisation of the overall machine concept, HPGRs POLYCOM can be integrated into both new and existing grinding plants without any problems from either the process technological or plant engineering points of view. Figure 1 presents a typical process flowsheet of a finish-grinding system.
The grinding plant can also be equipped with a ball mill following the POLYCOM. This is called a combi-grinding circuit. The main feature of such a system is the pre-grinding of cement clinker in the POLYCOM and a final grinding in the ball mill. The specific power consumption compared to a ball mill cement grinding is significantly lower and additionally paired with a 30 to 40 per cent increase in output.
