Low-energy, low CO2-emitting cements produced from coal combustion by-products and red mud

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15 Scopus citations

Abstract

Over the past 35 years or so, energy conserving or "low-energy" cements have been studied. The research presented herein studied the production and performance of calcium sulfoaluminate (CSA) cement, particularly that containing C2S ("belite"), termed CSAB, and CSA with calcium aluminoferrite, termed CSFAB. These cements are produced at lower temperatures than Portland cement and require less energy to mill. Furthermore, they require less limestone in the raw mix than Portland cement, so there are less CO2 emissions. However CSA cement requires a high-alumina raw material such as bauxite which is very expensive. The aim of this study was to formulate CSFAB cement using fluidized bed combustion (FBC) ash and red mud as raw materials and a minimum amount of bauxite. Mortar specimens were prepared from the CSFAB cements for compressive strength and dimensional stability testing. Several CSFAB cements were fabricated using lime, bauxite, FBC ash and red mud. It was possible to lower the proportion of bauxite in the raw mix by inclusion of red mud and produce a clinker comprising mainly iron-rich C 4AF, C4A3Ś, and C2S. Good compressive strength and expansion results were achieved on a CSFAB clinker that was formulated with 17% FBC ash and 15% red mud, and which was milled with 30% FGD gypsum. This cement developed strength mainly from the formation of ettringite from the reaction of C4A3Ś, gypsum and water. The aluminoferrite and belite did not react appreciably even after 3 months hydration.

Original languageEnglish
StatePublished - 2009
Event3rd World of Coal Ash, WOCA Conference - Lexington, KY, United States
Duration: May 4 2009May 7 2009

Conference

Conference3rd World of Coal Ash, WOCA Conference
Country/TerritoryUnited States
CityLexington, KY
Period5/4/095/7/09

Keywords

  • Fluidized bed combustion ash
  • Low-energy cement
  • Red mud

ASJC Scopus subject areas

  • Geophysics
  • Fuel Technology
  • Renewable Energy, Sustainability and the Environment

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