Characteristics of dolomite sand at different calcination temperatures and its stabilization effect on Mn2+ in electrolytic manganese residue.

In order to reduce the environmental impact caused by the migration of heavy metals in electrolytic manganese residue to water, this paper added calcined dolomite sand to electrolytic manganese residue to solidified Mn2+, and analyzed the microstructure and microstructure of dolomite sand before and after calcination by XRD, BET and SEM methods. The stabilization effect of calcined dolomite sand on Mn2+ in electrolytic manganese residue at different dosage was analyzed and evaluated. The results show that with the calcination temperature increasing from 600 °C to 800 °C, the dolomite sand gradually decompositions to form alkaline oxides such as CaO and MgO. The specific surface area, pore volume and pore size of calcined dolomite sand increase continuously, which are 1.16 ~ 3.96 times, 1.7 ~ 4.18 times and 1.99 ~ 16.12 times of uncalcined dolomite sand, respectively. When 10% calcined dolomite sand at 800 °C is added to electrolytic manganese residue, the stabilization efficiency of Mn2+ is 99. 95%, and when 30% calcined dolomite sand at 700 °C is added, the stabilization efficiency of Mn2+ is 99.85%, and the concentration of Mn2+ is as low as 1.66 mg/L. The stabilization effect of calcined dolomite sand on Mn2+ in electrolytic manganese residue is mainly that Mn2+ is solidified in the form of MnO2 and MnOOH. The calcined dolomite sand at 700 * 800 °C can be used as an effective stabilizer to solidified Mn2+ in electrolytic manganese residue. [ABSTRACT FROM AUTHOR]