Use of Industrial Byproducts as Alumina Sources for the Synthesis of Calcium Sulfoaluminate Cements

Abstract

Calcium sulfoaluminate (CSA) cements show some desirable environmentally friendly features that include the possibility of using several industrial byproducts as raw materials in their manufacturing process. Alumina powder, from the secondary aluminum manufacture, and anodization mud, from the production process of anodized aluminum, have proved to be suitable as partial or total substitutes for an expensive natural material like bauxite. CSA clinker generating raw mixtures, containing limestone, natural gypsum, bauxite, and/or one of the alumina-rich byproducts, were heated 2 h in a laboratory electric oven at temperatures ranging from 1150 to 1300 °C. Conversion of reactants into 4CaO·3Al(2)O(3)·SO(3) (the key component of CSA cements), evaluated using X-ray diffraction (XRD) analysis, increased with an increase of both burning temperature and byproduct concentration. When examined through differential thermogravimetric and XRD analyses, a synthetic CSA clinker (made from the raw mixture incorporating alumina powder as a total replacement of bauxite) mixed with 20% gypsum showed a hydration behavior almost similar to that of an industrial CSA cement containing the same amount of gypsum.

Research review of cement clinker chemistry

“…In addition to the change in the composition of the cements based on calcium sulfoaluminate towards increased content of belite, the use of waste materials containing high levels of aluminum and sulfates can contribute to cost reduction [117,118].…”

Influence of Calcium Sulfoaluminate (CSA) Cement Content on Expansion and Hydration Behavior of Various Ordinary Portland Cement‐CSA Blends

“…[1][2][3] Continuous push toward the development of sustainable cementitious binder has resulted in increased research activity on calcium sulfoaluminate (CSA) cement in the last few decades. [4][5][6][7][8][9][10][11][12][13] CSA cements are very interesting hydraulic binders for achieving both sustainability and durability. The production of CSA cement results in lower CO 2 emission than that of portland cement.…”

Binders alternative to Portland cement and waste management for sustainable construction—part 1

“…Apart from ye'elimite, belite (C 2 S) is another main phase in CSA cement, while secondary phases may include C 4 AF, C 3 A, C 12 A 7 , and C 6 AF 2 . 7 CSA cement is a sustainable cement when compared with ordinary Portland cement (OPC), 8,9 since less limestone is required due to the low CaO content in ye'elimite phase. 8,10,11 Moreover, more gypsum or anhydrite (CaSO 4 ) is needed to prepare CSA cement; therefore, the CO 2 released in CSA cement production process is much less than that in OPC production.…”