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The flotation behaviours of pure minerals such as spodumene, feldspar and quartz, and the effects on flotation index of spodumene ore were studied by flotation tests using sodium dodecyl sulphate, sodium dodecyl sulphonate, oleic acid, 731, naphthenic acid soap, and a mixture of oleic acid and dodecylamine as collector. Furthermore, the interaction mechanisms of the mixed collector were investigated by the measurement of Zeta potential, infrared spectrum analysis, adsorption amount measurement and quantum chemical calculation. The results indicate that the mixed collector of oleic acid and dodecylamine has the characteristics of good collection and selectivity and achieved flotation separation of spodumene from feldspar and quartz under alkaline conditions. The adsorption amount of mixed collector on spodumene is larger than on feldspar and quartz. Oleic acid is mainly chemisorbed on the mineral surface while the adsorption of dodecylamine on the mineral surface is physical adsorption. Oleic acid ions exist in association form with dodecylamine ions (or molecules) and oleic acid molecules, respectively. The group COO- of oleic acid reacts with Al atoms on the surface of spodumene., The flotation behaviours of pure minerals such as spodumene, feldspar and quartz, and the effects on flotation index of spodumene ore were studied by flotation tests using sodium dodecyl sulphate, sodium dodecyl sulphonate, oleic acid, 731, naphthenic acid soap, and a mixture of oleic acid and dodecylamine as collector. Furthermore, the interaction mechanisms of the mixed collector were investigated by the measurement of Zeta potential, infrared spectrum analysis, adsorption amount measurement and quantum chemical calculation. The results indicate that the mixed collector of oleic acid and dodecylamine has the characteristics of good collection and selectivity and achieved flotation separation of spodumene from feldspar and quartz under alkaline conditions. The adsorption amount of mixed collector on spodumene is larger than on feldspar and quartz. Oleic acid is mainly chemisorbed on the mineral surface while the adsorption of dodecylamine on the mineral surface is physical adsorption. Oleic acid ions exist in association form with dodecylamine ions (or molecules) and oleic acid molecules, respectively. The group COO- of oleic acid reacts with Al atoms on the surface of spodumene.

The effect of grinding on the spodumene flotation was investigated. The flotation response of spodumene ground by different mills was different, due to the variation of metal ions on spodumene surfaces caused by grinding environments and/or impurities. The samples were subjected to acid pickling treatment to remove most of the metal ions from the surfaces, and then all samples showed the same poor flotation response, which confirmed the significance of surface metal ions. Metal ion impurities may come from both grinding environments and lattice substitutions in spodumene. Density functional theory (DFT) calculation revealed that Fe and Ca could exist as lattice substitutions on the spodumene surface while Mg substitution is unlikely to occur. Furthermore, Fe is considered to be an active site for the absorption of sodium oleate on the spodumene surface. Morphology analysis showed differences in particle size and shape for samples ground by different mills, resulting in different amounts of exposed surfaces. The particle size, cleavage characteristics caused by grinding environments, and metal ion impurities originated from grinding and isomorphous substitutions, play significant roles in the chemisorption of collector on the spodumene surface. (Authors.), The effect of grinding on the spodumene flotation was investigated. The flotation response of spodumene ground by different mills was different, due to the variation of metal ions on spodumene surfaces caused by grinding environments and/or impurities. The samples were subjected to acid pickling treatment to remove most of the metal ions from the surfaces, and then all samples showed the same poor flotation response, which confirmed the significance of surface metal ions. Metal ion impurities may come from both grinding environments and lattice substitutions in spodumene. Density functional theory (DFT) calculation revealed that Fe and Ca could exist as lattice substitutions on the spodumene surface while Mg substitution is unlikely to occur. Furthermore, Fe is considered to be an active site for the absorption of sodium oleate on the spodumene surface. Morphology analysis showed differences in particle size and shape for samples ground by different mills, resulting in different amounts of exposed surfaces. The particle size, cleavage characteristics caused by grinding environments, and metal ion impurities originated from grinding and isomorphous substitutions, play significant roles in the chemisorption of collector on the spodumene surface. (Authors.)