Abstract
<jats:p>This study aims to address the issue of reduced filtration efficiency of magnetite iron ore concentrates in ceramic disc vacuum filters due to the introduction by mining and processing plants of an additional reverse flotation stage to minimize the SiO2 content in the flotation tails, which requires finer grinding and utilization of dextrin and amines as flotation agents. This work proposes a method for reagent-based modification of the magnetite surface to increase its hydrophilic properties and create conditions for formation of aggregates free of internal closed pores. The study examines the effect of the following flotation agents: starch (alkali-hydrolyzed) in combination with 3-(isodecyloxy)propylamine and polymers (agent A being an anionic polyelectrolyte based on acrylamide and sodium acrylate; agent K being a cation coagulating agent based on polydiallyldimethylammonium chloride) on the wetting and electrosurface properties of the commercial magnetite concentrate (Fe3O4 content of 97+%) and magnetite polished section. The results of measuring the limiting wetting angle, electrode and zeta potentials of the concentrate and the polished sections of magnetite before and after treatment with the examined agents helped to establish that the optimal filtration properties of the concentrate are achieved not by minimizing the individual surface parameters, but by balancing all the three characteristics through a targeted selection of agents. It was found that the cationic polymer (agent K) exhibits a combined mechanism of action, i.e. it neutralizes the negative charge promoting coagulation and simultaneously makes the surface hydrophilic, partially shielding the hydrophobic amine radicals. This makes it the most efficient agent for dewatering flotation magnetite concentrates.</jats:p>