Role of iron oxy-hydroxides on settling behaviour of red mud
| Autor: | Angela Nair Avelar, G. M. da Costa, Teresa Ribeiro, Efigênia Ferreira e Ferreira |
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| Rok vydání: | 2014 |
| Předmět: | |
| Zdroj: | Canadian Metallurgical Quarterly. 53:478-485 |
| ISSN: | 1879-1395 0008-4433 |
| DOI: | 10.1179/1879139514y.0000000137 |
| Popis: | Nine bauxite samples from Brazil and one from Ghana were submitted to alkaline digestion at 145°C. All initial samples and their red muds were chemically analysed and characterised by X-ray diffraction and Mossbauer spectroscopy at 298 and 77 K. The settling rates of all red muds were also measured. It was observed that the presence of goethite in the bauxite has a profound effect on the settling rate of the red mud produced in the Bayer process. The goethite possess high Al-for-Fe substitution and/or nanometric crystallites, and decreases the settling rate. The dissolution of this goethite during the caustic digestion at 145°C was also observed, leading to the formation of hematite. Finally, the hematite in the red muds presents crystals with larger sizes in comparison with those in the original bauxites.On a soumis a la digestion alcaline a 145°C, neuf echantillons de bauxite du Bresil et un echantillon du Ghana. On a analyse chimiquement tous les echantillons initiaux et leurs boues rouges et o... |
| Databáze: | OpenAIRE |
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