The role of surface roughness in the wettability and floatability of quartz particles

Abstract Surface roughness affects both the adsorption capacity of collector and mineral flotation separation. To investigate the role of surface roughness in quartz flotation, in this study, quartz particles were ground by different mills to produce two quartz samples with different nano-sized roughness, which was quantified with atomic force microscopy (AFM). Flotation experiments were carried out using CaCl2 as an activator and sodium oleate (NaOL) as a collector. The results of flotation experiments showed an excellent performance with high recoveries for the rough quartz particles in contrast to the case with the smooth ones. Surface chemical aspects for the role of surface roughness in flotation were investigated through measurements of X-ray photoelectron spectroscopy (XPS), Scanning Electron Microscope-Energy Dispersive Spectrometry (SEM-EDS), collector adsorption capacity and contact angle analysis. Both XPS and SEM-EDS results demonstrated larger adsorption capacity of Ca2+ for the rough quartz particles due to more adsorption sites provided by larger specific surface area. The NaOL adsorption capacity results also confirmed that larger surface roughness corresponded to higher adsorption capacity of NaOL. Subsequently, the contact angle results revealed that after interacting with NaOL the rough quartz particles presented more hydrophobic. Combined with flotation tests and surface chemical analysis, it might be arrived that surface roughness affected the adsorption capacity of both Ca2+ and NaOL, therefore impacting the wettability and floatability of quartz particles.