Hematite formation from jarosite type compounds by hydrothermal conversion
| Autor: | J E Dutrizac, Alba Sunyer |
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| Rok vydání: | 2012 |
| Předmět: | |
| Zdroj: | Canadian Metallurgical Quarterly. 51:11-23 |
| ISSN: | 1879-1395 0008-4433 |
| DOI: | 10.1179/1879139511y.0000000019 |
| Popis: | The hydrothermal conversion of K jarosite, Pb jarosite, Na jarosite, Na–Ag jarosite, AsO4 containing Na jarosite and in situ formed K jarosite and Na jarosite to hematite was investigated. Potassium jarosite is the most stable jarosite species. Its conversion to hematite in the absence of Fe2O3 seed occurred only partially after 5 h reaction at >240°C. In the presence of Fe2O3 seed, the conversion to hematite was nearly complete within 2 h at 225°C and was complete at 240°C. The rate of K jarosite precipitation, in situ at 225°C in the presence of 50 g L−1 Fe2O3 seed, is faster than its rate of hydrothermal conversion to hematite. In contrast, complete conversion of either Pb jarosite or Na–Pb jarosite to hematite and insoluble PbSO4 occurs within 0·75 h at 225°C in the presence of 20 g L−1 Fe2O3 seed. Dissolved Fe(SO4)1·5 either inhibits the conversion of Pb jarosite or forms Pb jarosite from any PbSO4 generated. The hydrothermal conversion of Na–Ag jarosite to hematite was complete within 0·75 h... |
| Databáze: | OpenAIRE |
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