Abstract

PIRES, Carolina; PONTE, Haroldo; RIBEIRO, Alexandra  and  PONTE, Maria José. Removal of lanthanum and neodymium from soils applying the electrokinetic process. Rev. de Ciências Agrárias [online]. 2022, vol.45, n.4, pp.521-530.  Epub Dec 01, 2022. ISSN 0871-018X.  https://doi.org/10.19084/rca.28505.

Rare earth elements are critical raw materials, which are essential for the development of society. The production of these species mainly occurs via the hydrometallurgical process and ion adsorption clays. However, these processes result in high environmental impact and high energy consumption. In this sense, the search for green technologies to extract these elements becomes crucial. The electromining is a technique that applies electrokinetics using green electrolytes to assist in the removal of metallic species from soils. The aim of this work was to evaluate the effect of different electrolytes in the removal of lanthanum and neodymium from soils, applying the electromining technique. To that end, two experiments were conducted using different electrolytes, in one citric acid and in the other oxalic acid, both at a concentration of 0.10 mol L-1. The electromining experiments were conducted applying an electric field strength of 1.0 V cm-1 for 240 h using 300 g of soil. The results showed that the higher removal occurred using citric acid, which extracted 63.2% of lanthanum and 34.7% of neodymium, with an electric consumption of 12.6 W h. In light of this view, electromining showed to be a feasible technique to remove rare earth elements from soils with low energy consumption.

Keywords : rare earth elements; electromining; organic acids; eco-friendly removal.

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