Fundamental Studies on the Surface Chemistry of Ancylite, Calcite, and Strontianite

The fundamentals of the surface chemistry of ancylite, strontianite, and calcite in the presence of hydroxamic acid (HXY) were investigated based on their zeta potential, adsorption, infrared measurement, and microflotation. Zeta potential studies indicate that the isoelectric points of ancylite, strontianite, and calcite are around 5.46, 4.50, and 5.50, respectively. HXY is chemically adsorbed onto the surface of ancylite, which was confirmed by both zeta potential and infrared measurements. At room temperature, the monolayer coverage of HXY on ancylite is shown as 20 A mu mol/m(2), which is much higher than the monolayer coverages for strontianite and calcite. In the comparison of adsorption densities of strontianite, calcite, and ancylite at both room temperature and 50 A degrees C, the results show that strontianite and calcite appear more sensitive to temperature than ancylite. Microflotation studies of pure minerals show that theoretically, calcite could be separated from strontianite and ancylite at pH 7.5 in the presence of 5 x 10(-4) M HXY, and ancylite can be separated from strontianite in the presence of 2 x 10(-4) M HXY when pH is around 9. However, as indicated from the zeta potential results, the dissolved species from minerals significantly change the flotation behavior of minerals' mixture. Thus, a successful flotation separation could not be achieved without any modifiers.