Synergistic effects between fatty acids and non-ionic reagents for the selective flotation of scheelite from a complex tungsten skarn ore

Tungsten skarns today represent >40% of the global tungsten reserves although their processing is usually difficult due to fine textures, low grade, and complex mineralogical association. Notably, selective flotation scheelite from gangue calcium minerals, particularly fluorite, using fatty acids still remains an industrial scientific challenge. In present work, we investigated influence pH, chain length unsaturation degree, mixing with different structures, non-ionic reagents on selectivity towards scheelite. Four were tested in micro-flotation at optimal pH 9. We demonstrated that short-length do not afford a good floatability while sodium oleate always exhibits very fluorite. Meanwhile, linoleate stearate more equilibrated properties. When are mixed, saturated unsaturated acids, increases, which is, however, favour fluorite whole studied range. However, introduction non-commercial unsaturated-fatty-acid-based mixtures did increase significantly tests conducted Tabuaço skarn ore. Though, use tall oil comprising provided better between compared classical formulations, it was enough attain satisfactory Finally, isotridecanol, alcohol, commercial formulations afforded significant scheelite, allowed attaining unprecedented WO3 grade 45.2% 56.5% recovery cleaning concentrate.