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- Title
PRECIPITAÇÃO DO SULFATO DUPLO DE TERRAS RARAS E SÓDIO A PARTIR DE UM LICOR SULFÚRICO DE TERRAS RARAS CONTENDO IMPUREZAS.
- Authors
da Silva, Ruberlan Gomes; de Morais, Carlos Antonio; Viana Teixeira, Leandro; de Oliveira, Éder Domingos
- Abstract
The non purified rare earth sulfate liquor used in these study contained 4.54 g.L-1 of rare earth oxides (REO), low acidity (<1.0 g H2SO4.L-1) and presented in its composition the following impurities Ca2+, Mg2+, Mn2+, Fe3+, Al3+, Th4+, UO2 2+ e PO43- . Part of this liquor was purified with limestone until pH=3.5 and after with lime until pH=5.0, and it was obtained a purified rare earth sulfate liquor free of Fe3+, Th4+ and PO4-3 and with a low concentration of Al3+, UO22+ and SO42-. The rare earth precipitation experiments using sodium sulphate (Na2SO4) indicated that the best chemical quality was obtained in rare earth-sodium double sulfates (NaETR(SO4)2.xH2O) produced from the purified liquor, presenting a REO content of 38% w/w, while the rare earth-sodium double sulfates from the non purified liquor contained a REO content of only 31% w/w. The main impurity was calcium (~3% w/w Ca). The REO recovery was 80% and the consumption of Na2SO4 was 1.3 ton per ton of REO in the feed liquor. The rare earth precipitation was carried out at 70°C. There was selective precipitation in specific groups of rare earth, being precipitated 82% of La, Ce, Nd and Pr, 53% of Sm, Eu and Gd and only 16% of Tb, Dy, Ho, Er, Tm, Yb, Lu, Y and Sc. Based on this results, it was proposed a process route where 80% of REO would be precipitated as NaREE(SO4)2.xH2O and the 20% remaining as rare earth oxides (>97% of REO) or as rare earth carbonates (>68% of REO).
- Subjects
RARE earth oxides; SODIUM sulfate; URANINITE; SULFATES; LIQUORS; LIMESTONE
- Publication
Tecnologia em Metalurgia, Materiais e Mineração, 2018, Vol 15, Issue 4, p399
- ISSN
2176-1515
- Publication type
Article
- DOI
10.4322/2176-1523.20181470