A comparison of the mineralogical characteristics and alkali roasting behaviour of red mud of different origins

V. Tathavadkar, A. Jha, T. Fülöp, T. I. Török, Á Rédey

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)

Abstract

The alumina refineries worldwide produce red mud waste which is highly alkaline with pH>12. Worldwide there is also shortage of high-grade bauxite for alumina production; consequently the tonnage of red mud produced has also increased, typically up to the rate of 2.5 tonnes for each tonne of alumina. The increase h the tonnage of red mud is dependent on the mineralogy of bauxite used in the Bayer process. Typically the extraction efficiency of alumina in the Bayer process varies between 45% for low and 60% for high grades of ores. Consequently the red mud derived from Bayer plants vary greatly. Hungary is one of the most important producers of alumina and aluminium metal in Central Europe. In the present investigation, we have compared the mineralogy of red mud samples obtained from MAL in Hungary, ALCAN in Scotland, and INDAL in India. The mineralogy of Hungarian red mud is very different from those of the compositions of ALCAN and INDAL red mud. The titanium dioxide concentration of INDAL red mud is much higher than those found in ALCAN and MAL red mud. In the present work, we have studied the soda-ash roasting of red mud in air in the temperature range of 823-1123K in an attempt to design a zero-waste process for the recovery of metal values from red mud. The phases formed were analysed to determine the mechanism of formation of water-soluble sodium aluminate. The effects of mineralogical properties of the red mud on the extraction efficiency of roasting reaction are discussed using the results of X-ray powder diffraction and scanning electron microscopic examination of reactions products.

Original languageEnglish
Title of host publicationREWAS'04 - Global Symposium on Recycling, Waste Treatment and Clean Technology - Proceedings
EditorsI. Gaballah, B. Mishra, R. Solozabal, M. Tanaka
Pages401-410
Number of pages10
Publication statusPublished - Dec 1 2005
EventREWAS'04 - Global Symposium on Recycling, Waste Treatment and Clean Technology - Madrid, Spain
Duration: Sep 26 2004Sep 29 2004

Publication series

NameREWAS'04 - Global Symposium on Recycling, Waste Treatment and Clean Technology

Other

OtherREWAS'04 - Global Symposium on Recycling, Waste Treatment and Clean Technology
CountrySpain
CityMadrid
Period9/26/049/29/04

ASJC Scopus subject areas

  • Engineering(all)

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  • Cite this

    Tathavadkar, V., Jha, A., Fülöp, T., Török, T. I., & Rédey, Á. (2005). A comparison of the mineralogical characteristics and alkali roasting behaviour of red mud of different origins. In I. Gaballah, B. Mishra, R. Solozabal, & M. Tanaka (Eds.), REWAS'04 - Global Symposium on Recycling, Waste Treatment and Clean Technology - Proceedings (pp. 401-410). (REWAS'04 - Global Symposium on Recycling, Waste Treatment and Clean Technology).