ECONOMICAL AND ECOLOGICAL CEMENT PRODUCTION BY USING HIGHLY FLEXIBLE GRINDING SYSTEMS

Abstract

The cement industry worldwide has undertaken tremendous efforts during the last 25 years to reduce the energy consumption for cement production and to reduce the CO2 – emissions successfully. A further approach for reduction of the CO2 – emissions per ton of cement is the substitution of clinker in cement by additives. Already 27% of the cement sold in Germany are slag cements and cements with additives have reached a market share of 8% in 1999 /1/. Before it was common practice mainly in countries in Southern Europe to sell composite cements containing pozzolana, limestone, flyash and other additives. Nowadays the European Standard EN 197 opens these possibilities for all cement manufacturers in Europe. The tendency to increase production of such cements is growing not only in Europe but world wide. Besides a growing demand for ground granulated blastfurnace slag used in concrete production can be observed mainly in North America and in China. India makes a wide variety of blended or composite cements using granulated blastfurnace slag and flyash and in fact over 30% of cement in India is produced as blended cement using these additives. Such developments request innovative technologies not only in the field of construction materials but also in the field of the grinding technology. Loesche has introduced in 1994 the 2+2/3+3 technology for cement production, which provides a grinding system that allows the cement manufacturers to maintain optimized throughput of the plant when they change from one kind of product to the other no matter what the changes in the particle size distribution of the mill feed, in the moisture and in the grindabiltiy are. The high mechanical efficiency of the Loesche mill allows production at considerable low cost levels due to lower energy consumption which is an additional economical advantage. Introduction