Opportunities for Use of Bauxite Residue in Special Cements 2020

Work on the use of bauxite residue in cement has been pursued for over 80 years with many successful technical studies and several large-scale initiatives which has led to industrial usage of bauxite residue at a number of Portland cement clinker production plants. The driving force behind the usage in the production of both Portland Cement and calcium sulfoaluminate /special cements is because the iron and aluminium contents of the bauxite residue.

The review has highlighted that the prospects of large scale utilisation of bauxite residue in cement are very promising. Firstly, because the iron and aluminium components of the bauxite residue are valuable additions in the production of both Portland Cement and ‘special’ cement clinkers; and secondly it has been shown at a laboratory scale by several research groups that bauxite residue may successfully replace clinker in blended cements at dosages between 10 and 20 wt%. If used as produced, this would have a significant impact on the cement industry CO2 emissions as the clinker production is responsible for 85 % of the total emissions in an integrated cement plant.

Calcium sulfoaluminate cements require both a higher Fe2O3 and Al2O3 content in the raw meal which could be partially satisfied by using bauxite residue. Despite some promising studies on using bauxite residue in special cements such as calcium sulfoaluminate cements, there does not appear to be any industrial usage. These belite cements generate less carbon dioxide than Portland Cement so offer environmentally attractive options. Iron rich, special setting cements with improved strength when compared to Portland Cement have been made with levels of up to 40 % bauxite residue.