Synthesis and Mechanical Characterization of Iron Oxide Rich Sulfobelite Cements Prepared Using Bauxite Residue

Abstract

The bauxite residue (BR) is the solid waste of largest generation by the aluminum industry, with a generation estimated in 10 million ton/year in Brazil. Its high alkalinity demands elevated costs to store it safely. Due to the high content of Al 2 O 3 and Fe 2 O 3 in BR, the present study evaluated its application for the synthesis of iron rich sulfobelite clinkers. Because of its composition, the cement made with this clinker presents environmental (30% to 62% reduction of CO 2 -equivalent emission), economic and even technical advantages over Portland cements. Formulations containing: limestone, gypsum, BR and clay, were fired at 1230°C to synthesize the clinkers. Variations in BR and clay content were studied to obtain three formulations, F-15, F-18 and F-21, of different Al 2 O 3 /Fe 2 O 3 ratio values. Cements containing more than 10.5 wt-% of BR achieved mechanical resistance comparable to Portland cements (CP-II-Z32 and CP-V-ARI) for 7 and 28 days of curing age.

Circular Economy and Solid Waste Management: Challenges and Opportunities in Brazil

“…Construction is one of the leading destinations of mining waste since this sector consumes a large amount of raw material. Brazilian studies have evaluated the use of waste from iron ore processing [35,36] and its first stages of industrialisation [37,38], as well as the waste from bauxite processing [39][40][41] to produce cement, mortars and concrete [37,38]. Other studies with this waste have proposed the use in the production of bricks, tiles, flooring etc.…”

Effect of the Cooling Regime on the Mineralogy and Reactivity of Belite-Sulfoaluminate Clinkers

“…Namely, sodalites can have Si/Al ratios ranging from , for a pure silica framework, to zero, for a pure alumina one such as ye'elimite [37]. Furthermore, the crystalline structure of ye'elimite accepts noticeable amounts of Fe 3+ instead of Al 3+ [38,39]. However, the Fe to Al average mass-ratio was lowest in the slowly cooled sample (0.10 compared to 0.11 and 0.14 for the air-quenched and non-linearly cooled clinkers, respectively).…”

Formation, Characterization and SEM Microanalysis of Yeelimite

“…Yeelimite ((CaO) 4 (Al 2 O 3 ) 3 SO 3 ), also called "Klein's salt", is one of the main components of sulfobelite (SB), calcium sulfoalouminate (CSA) and occasionally occurs in Portland-type cements [1][2][3][4][5]. CSA and SB cements can be promising alternatives to ordinary Portland cement (OPC), especially in the view of sustainable development and the circular economy [1,5], as their production requires less energy and produces less CO 2 emissions compared to OPC [1,2,5,6].…”