CEE Oct-Dec 2012

near to the source if flyash (Thermal Power Plants). These grinding units receive clinker through railway rakes and need to install wagon tipplers. For the effective utilization of wagon tipplers it becomes must to have sufficient space (equivalent to one rake length) on either side of wagon tippler. Therefore, railway facilities need much bigger area as compared to grinding unit. The plot size for the railway shall be approx. 50 m wide x 1500 m long. Keeping in mind the limitations of land, wagon traverse is being considered for one of the project of Holter. After the wagon is unloaded on wagon tippler, side arm charger places empty wagon on traverser table, wagon is shifted to another rail track (Exit track) through a wagon traverse where pusher ejects out empty wagon from traverse to exit track. This way the space requirement for the rail tracks reduces to almost half. However, one parallel rail track needs to be constructed besides the track for removal of wagons. Benefits of wagon traverse are usually case specific and in some of the cases, its inclusion could help the grinding greatly. Fly-ash blending In last 2 decades of economic growth, shortage of electrical energy government policies, have pushed private companies to enter into mega thermal power plants. These thermal power plants, along with existing ones are generating huge quantity of flyash. As the biggest user of Flyash (PPC production), cement producers are finding it lucrative to maximize use of Flyash. Some clients are setting grinding units, whereas in one case Holtec designed one Flyash blending unit. This concept drastically reduced the materi al and improved the consistency of PPC produced. The concept of Flyash blending unit is dependent on the fact, that Flyash generated by power plant is usually of approximately 2,000 blaines. That mean if the Flyash is separated between coarse and fine fraction , it needs grinding with the cement. This concept is particularly useful for the cement producers, who bring in Flyash from long distance (for example cement producer, who bring in Flyash from a distance of approximately 1500 km of distance). If their Flyash movement could be reduced to half (only coarse fraction) and on the other side of bulker movement, they carry out operation, they can substantially gain on cost of transportation. Conclusion The primary purpose of this paper is to make people aware about new material handling concepts available and help the industry in adoption of the same . Such adoption of the new material handling concept, could reduce the investment cost, handling time, number of equipment, dust generation and make the system more reliable. However such adoptions are usually case specific and vary with project requirement. Courtesy: Indian Cement Review, Sep. 2012, Pp34-36. I Quality ~.standards USE OF MATHEMATICAL PROGRAMMING IN ESTIMATING THE INGREDIENT PROPORTIONS OF BLENDED CEMENTS Dr. M. Nuri endif, Yrd. Do . Dr. Hediye T yde - Yaman* *Middle East Technical University-Civil Eng. Department, Ankara Introduction In general, cement produced with additives are called blended cements. Cement producers are utilizing additives, mostly pozzolanic in nature, to decrease the clinker content of a cement to cope with the sustainability issue. During the manufacturing of a blended cement the mineral additive is usually interground with the cement clinker and gypsum to a predetermined fineness. Due to the differences in the grindabilities of those ingredients, the fineness of each ingredient is different and this affects the properties of a blended cement. Therefore, it is almost impossible to determine the fineness of level of each ingredient for a given blended cement. Usually the chemical composition of a cement ingredient and the cement itself is characterized by the chemical analysis of a sample. The most common chemical analytical technique used is X– ray fluorescence spectrometery (XRF), which can identify a set of oxides and their proportions in the cement. In a typical chemical analysis of a cement sample, usually a total of 9 oxides is traced; including major ones such as, calcium oxide (CaO) to minor ones, such as sodium oxide (Na 2 0 ). These oxides can come from any of the ingredients that are present in any of the cement ingredients. 13