Cement and Energy

Current adivitics For these reasons, there is a concentrated search for more cflicient ways to minimise the d itect and indirect in1luencc of energy on the tina! product. A detailed in vestigation of milling plants with regard to optimisation shows that the energy results depend on the grinding circuit by the parts subjected to wear and tear and the interpretation of the process. Cementas Engineering, Germany, has summarised different possibili ties for a mean ingful gri nding circuit optimisation in the fo llowing categories : Grinding Machinery An energy savin g of up to 20% can be made through intell igentl y developed grinding machinery, consisting of the mi ll li ning, the intermediate diaphragm and the grinding media charge. Filliug degree of the mill A decrease in unnecessary heating of the product to be ground can be ach ieved by calculating the optimal filling of the mill. The employment of addi tional cooling plants can then be avoided. Air separator plant Through etlicient use of the air separator, the amount of fine powder can be reduced considerably. An over– grinding of the final product is prevented and energy consumption is also reduced. A constant form of the product to be ground (in contrast to deformed ball s or cylpebs) can reduce the wear and tear of the grinding machinery, as well as reducing the heat within the mill. Pract ical experience has shown, that reduction in producti vity (up to 30%) can result from worn out liners casi ng and deformed grinding balls. This underlines the importance of these parts in the process of production. Fig ure 2 may be used as a guideline to estimate the optimisation possibili ties within a traditional milling cycle with a ball grinder. The saving potential in thi s example is not to be seen as an addition but demonstrates which possibi lities are available. X'l.=up to , 7, ;ncr"eose possibitity Traditional milling cycle with a ball grinder. Production, energy wear and tear The manufacture of cement requires energy. This energy is not directly avail able for the raw grinding. The energy required for the grindi ng circuit is supplied by the mill drive, the gearing, the mill tube, the shell liners and the grinding media charge. The more effecti ve the power transmission of the individual stations, the more energy is available for the raw grinding. This makes the crushing process possible. The tool for transferring the power to the gril\ding ball is the shell lining of the mill tube. This power transmission is called 'activating the grinding media' . The acti vation is dependent on the design of the liners. The better the design is, the more energy is transmitted to the grinding media, which in turn leads to an optimisation of the grinding process. Cementas Engineering's experience has shown that the charge of the grinding media in a ball mill has a direct influence on the energy consumption of this mill. A high percentage of wear to the g rinding media and liners results in a considerable rise in the specific energy consumption. There is a direct con nection between energy consumption and wear on machin ery. Through increased wear, additional costs emerge in the form of loss of production during repairs and also addition al costs for spare parts. This also has an infl uence on the price of the fi nal product. 2 .. u