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INDIAN SCENARIO

The boiler slag is the molten form of coal ash that can be found both in the filters of exhaust
stacks and the boiler at the bottom. Boiler slag can be included in roofing shingles (a reasonably
safe application) and in structural fill. The molten ash, after solidification is crushed and is used
as aggregate in lightweight concrete masonry units and raw feed material for production of
Portland cement. Bottom ash has also been used as a road base and sub base aggregate and
structural materials. To meet required specifications, the bottom ash or slag may need to be
blended with other natural aggregates prior to its use. Discarded bottom ash and boiler slag
are either landfilled or transferred to storage lagoons. When sluiced to storage lagoons, the
bottom ash or boiler slag is usually combined with fly ash. This blended fly ash and bottom
ash or boiler slag are referred to as ponded ash. Approximately 30 percent of all coal ash is
handled wet and disposed of as ponded ash. The bottom ash is also used as snow and ice
control on roads and pavements in some countries [155, 156].
The different applications of ash are shown in Fig. 7.

FIG. 10
Different Usage of Coal Ash [155]

Waste Stabilization Mineral Filler in
Solidification 1.3% Blasting Grit, Roofing Mining Asphalt 0.2%
Granules 1.0% Applications
Snow and Ice Soil Modification 1.0%
Control 4.0% Stabilization 2.3% Agriculture <0.1%
Concrete, Concrete Structural Fills
Products, Grout Embarkments 46.6%
7.1%

Aggregate 7.7%

Miscellaneous Other
8.1%

Road Base Subbase
Pavement 9.7%

Cement - Raw Feed …
Cement - Raw Feed
for Clinker 11.1%

4.2.2

FEEDSTOCKS FROM INDIAN REFINERIES
India has recently emerged as one of the global players in refining industry. The current
production capacity is about 215 MMTPA [157]. There are about 23 refineries in India but only
8 are of more than 10 MMTPA capacity.

64 Methanol and DME Production: Survey and Roadmap | 2017