Cement, Energy and Environment

--- from installation to management and maintenance. Another area involves maintaining quality control in the laboratory where it is essential to know how to calibrate, since lack of accuracy can obviously cause many problems. Training in the centre will enable candidates to understand the roots of problems. The big investment in the Training Centres is paying off by ensuring that personnel, by listening to and learning from technical experts, will be equipped to confidently manage cement plants from start to finish". It is very much Lafarge's policy that all plants should follow basic practices, which seems obvious but then the Centres are dealing with a wide variety of international personnel from many countries. Frequent meetings are held to check that the basic practices are working . New products development is another topic where the Technical Centre is working with the plants: each country business unit analyses their market and the customer needs. Based on this analysis, new products are developed. The Technical Centre uses their previous experience in other countries, and the research centre resources, based in Lyon, to define and optimize these new products. Examples of the sort of work currently being carried out in the Europe Technical Centre include the following: • Looking at the reliability and maximum optimization of equipment. Giving support to maximize cost effectiveness in plants. • Looking at up grading equipment in preparation for the recovery period after the recession. • Looking at how to improve the use of alternative fuels in European plants. • Looking at how to optimize mills • Focus on spare parts and sharing experiences within the other Technical Centres • Looking at the production of new cements. such as dust– free cement • Solving mid-term maintenance problems • Continuing assessment of refractories and refractory management. Courtesy: World Cement, October 2009, Pp50-53. CONCEPT FOR A NEW GENERATION GRINDING UNIT WITHAVSD Sergey V. Kovalyukh, Meng and Vsevolod R. Kovlyukh, PHD, SPE Kvar, Ukraine, Outline the concept for their Tubular-Conical Mill with a variable-speed electric drive. Abstract Based on analyzing classical drum and tubular ball mills with a fixed structure, biconical and stage-type mills with a rigidly-variable structure, and mills with a variable-speed electric drive, an advanced grinding concept is suggested. It offers a new framework of views on the mechanism and technology of grinding. These views served as a basis for developing a general-purpose tubular-conical mill with a continuously-variable (integral) structure and a variable-speed electric drive. Introduction The ball mill (BM) is a conservative grinding unit that has resisted radical change (the first BM patent was granted in Germany in 1881). This is indicative of its merits and shows that it is indispensable, but at the same time, this r.1eans that it has critical drawbacks. The grinding problem is addressed based on partial solutions , namely: • Mill sectioning into chambers • Ball separation • Choosing the fill factor and ball grades. • Choosing the liner plate profile in each chamber • Choosing the cycle, industrial process scheme, grinding stages, etc. The origin of all drawbacks is the fixed structure of the BM, which is and obstacle affecting the grinding parameters . A transition from a rigid B M structure to a continuously- variable (integral) one would solve the grinding problem radically. Many factors affect grinding; however, generally, B M performance is evaluated by its milling productivity per power consumption. Let us consider several well-known empirical productivity formulas for three types of mills: Cemem mill: Q=kV.fD~ ( I) Coal mill: (Z) Ore mill: Where 8 and Q is mill productivity (tph); k is constant factor; V is mill grinding space (m 3 ); 0 is inner dia. (m); L is mill length (m); G is mass of balls (t); <p is grinding bodies fill factor; and n is mill rotational speed (rpm). II