Tecnologia em Metalurgia, Materiais e Mineração
https://tecnologiammm.com.br/article/doi/10.4322/2176-1523.1131
Tecnologia em Metalurgia, Materiais e Mineração
Artigo Original

DIDYMIUM SEPARATION FROM LANTHANUM BY SOLVENT EXTRACTION USING 2-ETHYLHEXYLPHOSPHONIC ACID MONO-2-ETHYLHEXYL ESTER AND LACTIC ACID

SEPARAÇÃO DE DIDIMIO E LANTÂNIO A PARTIR DA EXTRAÇÃO POR SOLVENTES USANDO ÉSTER MONO-2-ETIL-HEXÍLICO DO ÁCIDO 2-ETIL-HEXIL FOSFÔNICO E ÁCIDO LÁCTICO

Scal, Maíra Labanca Waineraich; Seruff, Luciana Amaral; Vera, Ysrael Marrero

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Abstract

This article reports the separation of didymium from lanthanum by solvent extraction using 2-ethylhexyl phosphonic acid mono–2–ethyl hexyl ester (HEH(EHP)) as extracting reagent. The aim of the study was to evaluate the effect of lactic acid addition as well as the feed solution pH variation on the didymium separation from lanthanum. We carried out batch and continuous extraction experiments. In batch experiments, we observed that the extractions of REEs increased along with the increase of lactic acid concentration and feed solution pH. The best conditions for Pr/La separation were obtained at pH 3.5 and lactic concentrations varying between 1.1 and 2.6 times the total REE molar concentration. In the continuous extraction experiments, when no lactic acid was added in the feed solution and with A/O 1:1, the extractions of La, Pr and Nd were 2.0%, 22.3% and 29.5%, respectively. When lactic acid was added in the feed solution, the extractions of La, Pr and Nd were 7.0%, 57.8% and 73.7%, respectively. The addition of lactic acid in the feed solution increased the REE total concentration in the loaded organic phase, the Pr/La separation factor and the total REE mass flow rate, by 2.6, 2.8 and 2.7 times, respectively.

Keywords

Solvent extraction, Rare earth elements, Lactic acid, HEH(EHP).

Resumo

Neste trabalho estudamos a separação de dídimo e lantânio utilizando a técnica de extração por solventes e com o extratante éster mono-2-etil-hexílico do ácido 2-etil-hexil fosfônico (HEH(EHP)). O objetivo deste trabalho foi avaliar o efeito que sobre a separação de didímio e lantânio tem a adição de ácido lático e a variação do pH da alimentação aquosa. Realizamos ensaios em batelada e em regime contínuo. Nos testes em batelada, observamos que o aumento da concentração do ácido láctico e do pH aumentaram a extração dos ETRs. As melhores condições de separação de Pr/La foram obtidas em pH 3,5 e ácido láctico em concentração de 1,1 a 2,6 vezes a concentração de ETRs. Em regime contínuo, para uma razão de fases A/O 1:1 e quando o licor não foi condicionado com ácido lático, as extrações de La, Pr e Nd foram: 2,0%, 22,3% e 29,5%, respectivamente. Quando o licor foi condicionado com ácido lático as extrações de La, Pr e Nd foram: 7,0%, 57,8% e 73,7%, respectivamente. A adição de ácido lático na alimentação aumentou a concentração total de ETRs na fase orgânica carregada, o fator de separação Pr/La e a vazão mássica total de ETRs em 2,6, 2,8 e 2,7 vezes, respectivamente, quando se compara com o teste sem a presença do ácido lático na alimentação.

Palavras-chave

Extração por solventes, Elementos de terras raras, Ácido lático, HEH(EHP).

Referências

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