Sintered Flyash Light Weight Aggregates

 InGlobal Resources

Model Plants in China

Mr. Pankaj Verma, Assistant General Manager-Technical, InGlobal Resources tells Built Expressions that lightweight fly ash aggregate obtained from coal burning power plants is an excellent alternative to natural quarried aggregate.

Disposal of fly ash, a waste arising from coal fired thermal power stations currently poses a serious operational constraint and environment hazard. A 100 mw thermal unit generates about 0.15 million tones of fly ash per annum when using coals with an ash content of 40% at this rate the present annual generation of fly ash would be of the order of 25.0 million tones approx. hence making the technology of fly ash bricks a significant important in coming years.

InGlobal Resources produces artificial lightweight Aggregate (LWA) from fly ash, a waste product of coal burning power plants. The product is an excellent alternative to natural quarried aggregate, being strong, light and consistent.

• Sintered Flyash ligth weight aggregate substitutes natural stone aggregate/ chips in concrete, reducing dead weight.
• It can also be used in production of light weight precast concrete blocks, for use in load and non-load bearing elements.
• Local availability of Flyash from thermal power plant opens up good potential scope and more so where stone aggregates are costly or scarce.
• It meets concrete properties requirements to achieve high compression strength, slump/slump loss, pumpability/workability measured by splitting tensile strength, flexural modulus and modulus of elasticity of concrete.

Process

The process uses above 90% Fly Ash as major raw material mixing with small volume additive, carbonaceous solid fuel and water. The additive can be clay, and coal contributes the carbon depending on the particle size and loss of ignition in fly ash. After agglomeration and pelletizing, the green pellets will be transferred to a sinter machine for sintering. The physical characteristic of LWA product is superior to Natural Aggregates. 

Typical physical characteristics of LWA product:

Applications:

• Structural Lightweight Concrete
• Floor and Roof Screeds
• Roof tiles
• Land Drainage
• Bulk fill
• Precast
• Arrestor beds
• Hortag-a growing medium
• Filter Media
• Refractory

Energy Saving and Environmental Protection:

-Energy-saving in production process

Producer gas from Coal is used for ignition/start of sintering process. After the first layer of sintering bed is ignited, the rest of green pellets will be sintered by the self-contained carbon in flyash with downdraft air. Gas/Oil can substitute electricity where so ever available and at economic cost.

-Energy-saving products

Flyash LWA has an excellent thermal insulation property. The concret made by flyash LWA has thermal insulation ration 0.118-0.6/m.k, which is much lower than regular concrete.

-Environmental Protection

Dust Collector

Flyash is a byproduct of coal burning power plant. Most of flyash is dumped as waste material. Using InGlobal Resources sourced plant and technology; would enable handling large quantity of flyash, thereby not only saving large volume of scarce land but also protecting air from pollution.

-Dust in the manufacturing process can be collected by dust collector with negative pressure; exhaust from chimney <50mg/m3.

By using lightweight aggregate, we can enhance various properties like reduce the weight of structure and the requirement of high compression strength, slump/slump loss, pumpability/ workability measured by split tensile strength, Flexural Strength and modulus of elasticity in concrete. LWC prepared by sintered LWA has enhanced insulating properties comparable to the conventional concrete.

 This kind of lightweight aggregate is yet to manufacture in India. To begin Fly ash LWA market Promotion in LWC will follow soon. InGlobal supplies complete plant package to manufacture lightweight aggregate in different capacity modules. Because of its Properties and Compatibility, growth rate of LWC will be remarkable in high rise buildings and it awaits for manufacturing in India.