CCR characterization and valorization as mineral additives during cement production in India

ABSTRACT

The study emphasizes on physico-chemical, mineralogical, morphological, and mechanical characteristics of Coal Combustion Residues (CCRs) collected from two different thermal power plants. To determine utilization potential and valorization, specifically in the Indian cement sector more than governing guidelines of Indian Standards (IS), collected CCRs (Fly and Bottom Ash) samples were analyzed for physical, chemical, and mechanical characteristics. The characterization included pH, moisture content, acid insoluble residue, chlorides, reactive silica, LOI, carbon, Blaine fineness, XRF, SEM, XRD, FTIR, initial and final setting time, consistency and soundness, lime reactivity, and compressive strength at 7, 28, and 90 days. The characteristics were analyzed and selected with a view to determine their suitability as mineral additives in the cement sector. The study showed that; collected CCR samples fulfill the requirements of the Indian standard (IS:3812) as well as ASTM C-618 for physico-chemical and mechanical characteristics and show potential for increased use in the cement industry as mineral additives. The study also highlights that; up to 30% CCRs can be used as a mineral additives during cement manufacturing, and if long-term strength is considered up to 50% replacement can be possible.

KEYWORDS:

• Coal bottom ash
• Coal combustion residues (CCRs)
• coal fly ash
• mechanical characteristics
• physico-chemical characteristics

Acknowledgment

The authors thank Director, National Environmental Engineering Research Institute (CSIR-NEERI) India, for his permission to conduct these research studies.

Funding

The authors are thankful for financial assistance provided by Sinteff Norway for the BILAT-INDIA project.