Using brucite-containing waste from refractory manufacturing, when treating wastewater to remove copper, nickel and cadmium ions

Increasing attention is paid to issues related to electroplating wastewater treatment. It is equally important to search for, and introduce new highly efficient technologies of processing bulk mineral waste accumulating at various plants. As part of the conducted research, we assessed an opportunity of using brucite-containing waste from refractory manufacturing as an experimental chemical agent for precipitation of heavy metal ions. Efficiency of removal (precipitation) of heavy metal ions was studied on model wastewater of rinsing parts on the electroplating section. It has been established that an efficient dose of brucite-containing waste to reach a standard residual concentration of heavy metals of 0.05 mg/dm3 or less is 2.0 g/dm3. It has been determined that minimum period of the brucite-containing waste/wastewater contact is 45 minutes. Heat treatment of brucite-containing waste at 500 оС during 60 minutes contributes to a considerable increase in heavy metal precipitation efficiency and reduction of a dose of the chemical agent for precipitation to 1.5 g/dm3 without losing efficiency. Water treatment from heavy metals is supposed to include parallel processes of neutralization, forming poorly soluble hydroxides, sorption of combinations of heavy metals on the surface of brucite-containing waste, and processes of ion exchange on the surface of magnesium oxides. Using wastes from refractory manufacturing in processes of engineering protection of environment will contribute to not only reducing volumes of waste dumping, but also making the first step to implementing the Zero Waste concept as part of closed-loop economy.