Separating fine spodumene from K-feldspar with sodium oleate, glycine collector and flocculation-flotation with anionic polyacrylamide

Recovering fine spodumene by flotation remains challenging because bubble–particle attachment is inefficient. Selectivity between spodumene and K-feldspar is particularly difficult because the two aluminosilicates present closely similar surfaces. We build on selective separation of spodumene from quartz using Ca(II)-activated flocculation–flotation with anionic polyacrylamide (PAM) and sodium oleate (NaOl). The current study compares sodium oleate with a glycine-based collector (BASF DP-OMC-1396) and evaluates polymer-assisted flocculation-flotation. Flotation is investigated across increasing complexity: synthetic binaries of spodumene and K-feldspar; a ternary spodumene–K-feldspar–quartz mixture; and real ore from Mt Cattlin, Western Australia. Ca(II)-activated NaOl is effective in a narrow pH and dosage window. The glycine-based collector performs strongly in Ca(II)-free spodumene–K-feldspar mixtures at 500 g/t; in the ternary system, which contains more spodumene (30 wt%), comparable upgrading requires 1500 g/t. Expressed per unit of spodumene in the feed, the two dosages are similar (∼4350 and ∼ 5000 g/t of spodumene), indicating that collector demand scales with spodumene content rather than that selectivity is lost. Polymer-assisted flotation with anionic PAM–NaOl increases recovery in the synthetic systems but lowers grade, a response consistent with the flotation of mixed-mineral aggregates, since Ca(II)-activated anionic PAM is known to aggregate both spodumene and K-feldspar. In the Mt Cattlin ore, flocculation-flotation increases mass pull without improving selectivity. Alkaline attrition scrubbing at pH 12.5, which combines slime rejection with alkaline conditioning of the mineral surfaces, enables the glycine-based collector to deliver the only genuine upgrading observed on the ore (∼16–24 wt% spodumene, extending to ∼ 70 % recovery at higher collector dosage).