First-principles study on the surface properties and floatability of magnesite tailings and its main gangue

Abstract

The accumulation of magnesite tailings (MT) poses challenges such as resource wastage, land occupation, dust generation, and environmental pollution, thereby jeopardizing both physical and mental health. Urgent attention is required for the proper treatment of this solid waste material. An in-depth investigation into enhancing the flotation processes of MT is essential. A comprehensive comprehension of the surface properties of MT and its principal gangue minerals assumes paramount importance in facilitating the desilication and decalcification of MT via flotation. In this investigation, a first-principles study grounded in density functional theory was employed to scrutinize the surface properties, as well as the similarities and differences in flotability, of four minerals-quartz, magnesite, dolomite, and calcite. The findings reveal that quartz's primary cleavage plane is (1 0 1), whereas that of magnesite, dolomite, and calcite is (1 0 4). The surfaces of magnesite, dolomite, and calcite exhibit chemical similarities, with Ca atoms demonstrating higher reactivity than Mg atoms. The hydrogen bonding between dodecylamine and quartz emerges as the most robust, while adsorption energies with the three carbonate minerals exhibit minimal disparity. The ongoing focus lies on the selection and optimization tests of decalcification reagents. A moderate quantity of dodecylamine manifests a certain desilication effect. However, excessive dosage compromises selectivity. The first-principles approach offers guiding significance for elucidating the surface properties of MT and its primary vein minerals, along with investigating the adsorption mechanisms of flotation regents.