Page 37 - Technology Compendium

CSIR-IMMT/EXM - 08

Recovery of value added products from Indian fly ash

Advantages / Salient Technical Features Application/Uses
• Processing of fly ash and recovery of multiple values • Alumina - utilized in aluminium industry and
present in fly ash : Alumina, calcium silicate, quartz other chemical industries,
residue and iron hydroxide residue. • quartz - used for glass making
• REEs concentrated in iron hydroxide residue - used as • Calcium silicate - used in board making and
starting materials for REEs extraction. other applications in chemicals& ceramics
• Holistic utilization of fly ash industry
• Application of calcium silicate for ceramic
Problem being addressed ware (cups) preparation was carried out.
• Utilization of fly ash
• Exploring secondary resources for strategic and Scale of Development
critical metals • Process has been developed at bench scale
• Import substitution of the said materials (TRL 5)
• Fulfilment of Aatma Nirbhar Bharat • Pilot scale tests have been planned (TRL 6)

Environmental Considerations (if any) Commercialization Status
• Beneficial • NA
• Fly ash utililization – pollution mitigation
• Supplement in aluminium production Techno-economics
• Reduction in mining of primary ores. • NA

Major Raw Materials to be Utilized Technology Package
• Fly ash obtained from industries with coal power • IMMT can develop process flow sheet
plants. Other chemicals include sulphuric acid and for recovery of metal values for similar
sodium hydroxide. metal bearing resources, carry out pilot
scale studies (optional) and prepare basic
IPR Status / Details (India/Abroad) engineering process package.
• Patented process for recovery of alumina, silica & iron
values from NALCO fly ash developed by CSIR-IMMT
( Indian patent no: 344358 Granted-18th Aug 2020 ).

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