Mineral Processing of Eudialyte Ore from Norra Kärr

Eudialytes are a nonconventional source for rare earth elements (REE). As the total REE content of eudialytes is relatively low, high-grade mineral concentrates have to be produced. The applicability of magnetic separation and direct selective flotation for the processing of eudialyte ore from Norra Kärr (Sweden) was tested. The eudialyte in the used sample contains around 4 % of REE. Magnetic separation is applicable for eudialyte ore processing. The higher the strength of the magnetic field, the higher the recovery. Recovery of around 81 % of REE was achieved in a two-stage process of rougher and scavenger at a mass reduction of 48 %. The concentrate grade of around 0.76 % REE is not sufficient for further hydrometallurgical processing steps. A newly developed reagent regime for the direct selective flotation of eudialyte from eudialyte ore was tested with different samples. The regime consists of oxalic acid and sodium hexametaphosphate as depressants and a mixture of mono/di phosphoric acid esters as collector, at a pH below 4. This new method proved applicable for raw ore as well as magnetic preconcentrate. Concentrates with grades of around 2 % Σ Y, Ce, La were produced.