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Ananda Kumar M. G. ¹, Shekhar Kumar M. ¹, Suryanarayana K. ¹, Vynatheya S. ¹, Venkatesh T. R. ¹, Seetharamu S. ¹, Jagannath Nayak ²

Affiliations
1 Materials Technology Division, Central Power Research Institute, Bengaluru - 560080, IN
2 Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Surathkal - 575025, IN

Abstract

In India, about 60% of the total power generation comes from thermal power stations operating on fossil fuels like coal and lignite [1]. Presently about 400 million tons of coal and lignite is consumed annually for power generation. Typically, Indian coals have an average ash content of about 45%, thereby leading to generation of around 180 million tons of ash annually as an industrial by product.

Out of the total ash generated, 70 % of this ash comprises of fly ash and the remaining are bottom ash, economizer ash, air-preheater ash, etc. Presently, dry fly ash is being utilized in a big way in value added products like bricks, blocks, pavers, etc., while bulk volumes of fly ash is consumed in blended cement manufacture, different types of concrete, construction of dams, roads, river embankments, etc.

Fly ash also contains about 1.0 % hollow particles called as ‘Cenospheres’ generated during combustion of the pulverized coal at high temperatures in the thermal power plant boilers. Cenospheres is a useful by-product of coal combustion which can be harvested from the ash ponds or by any other methods such as tribo-electric separation, slurry precipitation, pond skimming etc., from fly ash. Fly ash cenospheres are unique in the way that they possess excellent properties such as lightweight, low density, nonmetallic, high melting points. These unique properties make cenospheres a prospective raw material to produce value added products for use in engineering applications. The paper discusses the work carried out at Central Power Research Institute on cenospheres characterization and development of value added products for various applications.

Keywords

Fly Ash Cenospheres, Microspheres, Ash Pond, Alumino-silicate, Comprehensive Characterization, Engineering Applications

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Ananda Kumar M. G. ¹, Seetharamu S. ¹, Jagannath Nayak ²

Affiliations
1 Materials Technology Division, Central Power Research Institute, Bangalore 560 080, IN
2 Department of MME, National Institute of Technology-Karnataka, Surathkal- 575 025, IN

Abstract

Aluminium Metal matrix Composites (AMC) have been fabricated through powder metallurgy route comprising of Aluminum as matrix and reinforced with Cenosphere, a low density material in the form of hollow and porous spheres. The densification of the composite has been carried out in an advanced processing technique called the microwave sintering,which is rapid and economical. AMC with Cenosphere addition of 40 volume % has been prepared and sintered at various temperatures. The sintered composites have been studied for the mineralogical phases by XRD, morphology by SEM and physical properties such as Density, Apparent Porosity and Hardness (BHN). The results obtained have been compared with AMCs that were sintered conventionally. The microwave sintered samples showed better properties in terms of Porosity, Bulk Density and Brinell hardness values compared to the conventionally sintered ones.

Keywords

Cenosphere, Microwave Sintering, Aluminum Metal Matrix Composite, Powder Metallurgy.

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