resumo
The red mud (RM) is a solid waste derived from the processing of bauxite ore to produce alumina and it is considered a hazardous waste due to its high pH. This paper describes the use of mud untreated and after calcination at distinct temperatures (450, 650, and 1000 degrees C) attempting to improve its reactivity. The Portland cement was replaced up to 30 wt% red mud, and its addition changed the hydration process, evaluated by calorimetric studies of early hydration and setting time. By comparing with the reference mixture (without red mud), the obtained results confirm the potential of the red mud to be used as pozzolanic additive to cementitious materials. Temperature of hydration was monitored by a quasi-adiabatic calorimeter (Langavant). The hydration temperature increases with RM addition, particularly if calcined in the same interval (450-650 degrees C). In this condition, the hydration process is accelerated.
palavras-chave
BAUXITE
categoria
Engineering; Materials Science
autores
Ribeiro, DV; Labrincha, J; Morelli, MR
nossos autores
João António Labrincha Batista
Professor Associado com Agregaçãoagradecimentos
The authors wish to thank the CNPq - National Counsel of Technological and Scientific Development (Brazil) and the UA/DECV - Ceramics and Glass Engineering Dept., University of Aveiro & CICECO (Portugal) - Project FCT-PTDC/CTM/65243/ 2006, for their support of this research. The authors also thank Dr. Luciano Senff for help on calorimetric measurements. This project did not have the financial support of Alcoa Brazil.