Cement, Energy and Environment

recognised as accumulated profit shared in advance and credit for the same can be taken in the years of higher profits. This will provide some relief to the miners. Conclusion Given the need of including local population in the growth and development happening as result of mining activities, the profit sharing proposition seems to be a step towards realising their dream but at the same time, 26 percent burden seems to be too high to discourage industries from taking CSR measures and invest in the development of local infrastructure and people. Another huge impact of 26 percent profit sharing can also be unavailability of many mining projects, thus reducing the pace of growth of mineral sector which is the backbone of the economy. Thus, before the draft prov1s1ons are finalised and takes shape of Act, a balance need to be made between the rights of local population and growth of mineral industry as whole. Courtesy: 'editorial@infraline. com' dt Dec 04, 2010 WET FLY ASH DRYING FOR CEMENT INDUSTRIES Need of the Hour: India's 80% power requirement is sufficed by Thermal Power Plants. As Indian coal contents on average 35% ash, the fly ash generation is inevitable. In the coming years, disposal of fly ash is going to become major challenge with the increase in Power Demand from growing Indian Industry. At present, primarily, the fly ash is disposed off using either dry or wet disposal method. In dry disposal, the fly ash is transported by truck, chute or conveyor at the site and disposed off by constructing a dry embankment (dyke). In wet disposal, the fly ash is transported as slurry through pipe and disposed off in impoundment called "ash pond". Cement Perspective: Fly ash, a fine, glass powder<& recovered from the flue gases in coal based Power Stations consists primarily of silica, alumina and iron. When mixed with lime and water the fly ash forms a cementitious compound with properties very similar to that of Portland cement. Because of this similarity, fly ash can be used to replace a portion of cement in the concrete, providing some distinct quality advantages. The concrete is denser resulting in a tighter, smoother surface with less bleeding. Utilization of Fly Ash in Cement: Benefits to Cement Industry: • As a Partial replacement of costly raw materials such as shale, clay, limestone, sand which is normally used in as raw materials in cement manufacture. • Usage of fly ash means increased capacity /production which results in net savings. • Availability of sustainable/ compatible product at a lower cost to the consumers. • Less carbon em1ss1ons, reduced pollution levels and Clean Development Mechanism (COM) benefits. Why Fly Ash Drying? Apart from Dry Flash, Wet Fly Ash from "Ash Ponds" is also available in ample quantities. If this Wet Fly ash is utilized then the same Ash Dykes can be utilized instead of constructing new ones, saving money and land. Also, the wet fly ash is available at cheaper rates as compared to dry fly ash. Specific Benefits of using Dried Fly Ash in the cement manufacturing process: • At present Cement Industries are using wet fly ash and mixing it at pre grinding stage. However, due to up to 25% moisture content in the Wet Fly Ash, the mixing percentage is limited up to 2 to 3% as performance improver in OPC as against 15% to 35% in Portland Pozzolana Cement (PPC). • Dried fly ash can be directly mixed with the final product i.e. PPC or OPC, up to 5 % as performance improver. • Capacity of the Grinding Mill does not need to be increased to get enhanced production. Advantages of Fly Ash Drying Plant in Cement Plant Premises: • Wet fly ash can be easily sourced since, abundantly available with nearby TPP's. • Special transportation arrangement, handling & storage required for dry fly ash can be avoided. • Waste heat if available in the plant can be utilized for drying. 5