The changes of surface properties and enhancement of B2O3 leaching ratio of boron concentrate via wet ball milling

Abstract

With the ascharite used up in China, boron concentrate was used as raw material for extracting B2O3. In this study, an environmental wet ball milling (WBM) method was proposed to enhance the B2O3 leaching ratio, and the effect of liquid medium, rotational speed and milling time on the properties of boron concentrate in WBM process was discussed. This surface properties of milled samples was characterized by BET, PSD, SEM, XRD, FTIR, TG-DSC and XPS analyses, and their surface free energy was calculated by the measurement of contact angle. The role of liquid medium and the relationship between the surface properties was also explored. Our research shows liquid medium helps avoid the agglomeration and plays a dispersing role in the process of milling, thereby promoting the increasing of the specific surface area from 16.65m2/g to 35.84m2/g after milling for 60min. Besides, the B2O3 leaching ratio can be enhanced from 67.52% to 86.24% under the same conditions. The increased amorphous extent of crystal structure and the weakening of chemical bonds caused by the milling process helps produce an increasing in the number of reactivity points, making chemical reactions easier. With the increasing of surface free energy from 26.88mJ/m2 to 39.55mJ/m2 after milling, the hydrophilicity of the sample is enhanced, as well as the absorption of solvent and OH– in the leaching solution, thus promoting the leaching reaction and the enhancement of B2O3 leaching ratio.