Insights into the influence of calcium ions on the adsorption behavior of sodium oleate and its response to flotation of quartz: FT-IR, XPS and AMF studies

Assiduous efforts on the high-efficiency flotation of quartz with calcium ion activation have been ongoing, while there is a lack of understanding of its potential mechanism. In this research, insights into the influence of calcium ions on the adsorption behavior of sodium oleate and its response to flotation of quartz were systematically investigated. Micro-flotation experimental results show that addition order of calcium ions influences the quartz flotation. Ca2+/NaOL complexes exhibit higher flotation recovery of quartz (92.18 %) under the recommended conditions. The Zeta potential and Fourier transform infrared spectroscopy results indicate that the adsorption of NaOL onto bare quartz surfaces is extremely difficult, and the addition of Ca2+ promotes the adsorption of NaOL. X-ray photoelectron spectroscopy analysis results confirm that Ca2+/NaOL complexes reinforce the adsorption of NaOL and Ca2+ onto quartz surface by the formation of -Si-O-Ca-OOCR, and the Ca-OOCR content in the total Ca reaches 62.61 %. The adsorption amount results further illustrate that the adsorption amount of Ca2+ and NaOL increase to 18.56 x 10-2 mg/g and 40.83 x 10-2 mg/g, respectively. Additionally, starch slightly decrease the adsorption amount of Ca2+ on quartz surfaces. Atomic force microscope analysis reveal that Ca2+/NaOL components promote the formation of Ca-OOCR colloid precipitates and the transportation of the precipitates to the quartz surface. The main adsorption of Ca-OOCR colloid precipitates contributes to the enveloped bulge image. Notably, the Ca-OOCR colloid precipitates adsorption mechanism exerts more important role in the adsorption of sodium oleate and calcium ion species, as well as its response to flotation of quartz.