Investigations on the reverse cationic flotation separation of quartz from hematite using polyaspartic acid as depressant

The depressant polyaspartic acid (PASP) was used to study its selective inhibition behavior in the reverse cationic flotation of hematite from quartz. Microflotation experiments were used to study the flotation behavior of hematite and quartz under different reagents, and artificial mixed mineral experiment was used to verify the separation effect of PASP on the two minerals. The selective adsorption mechanism of PASP on hematite surface was revealed by surface wettability analysis, zeta potential test, adsorption density test and X-ray photoelectron spectroscopy (XPS) analysis. Microflotation experiments showed that PASP was an efficient and selective hematite depressant under alkaline conditions. The artificial mixed mineral experiment proved that PASP can achieve efficient flotation separation of two minerals. Mechanistic experiments (Surface wettability analysis, zeta potential test, adsorption test, and XPS analysis) revealed that the depressant PASP selectively adsorbed on the surface of hematite, which significantly enhanced the hydrophilicity of the hematite surface and significantly negatively shifted its surface zeta potential. The depressant PASP was selectively chemisorbed on the surface of hematite mainly through the complex reaction between polar groups such as –NH- and –COO- in its molecule and the iron ion species on the surface of hematite.