Surface properties changes during a two-stage mechanical activation and its influences on B2O3 activity of boron concentrate

Abstract

A two-stage mechanical activation (MA) method by combining the dry milling with subsequent wet milling was applied on processing boron concentrate. The properties of samples were characterized by Particle size analysis, Brunauer-Emmet-Teller, Scanning Electron Microscope, X-ray Diffraction, and Fourier Transform Infrared analyses, respectively. In addition, the wettability was measured and the surface free energy was calculated, by the measurement of contact angles, the dispersion in ethanol and water was determined according to the difference of sedimentation rate of different particles in water using spectrophotometry, and the B2O3 activity was determined by alkaline leaching. The two-stage MA exhibits an obvious advantage for refining particles—the particles were refined rapidly and the specific surface area increased to 33.587 m2/g in 30 min milling, higher than that of products obtained by wet milling or dry milling alone. The damaged crystal structure and chemical bonds makes the chemical reaction easier. The surface free energy and Lewis acid component were enhanced, promoting an increase in absorption of solvent and OH−. Thereby, the B2O3 activity increased greatly from 67.52% of the untreated boron concentrate to 89.15% only in 30 min milling.