Study on Extraction of Mg from Boron Mud

Mg was extracted from boron mud through calcining method. The technological process is that the boron mud was calcined at 700 °C for 3 h then uniformly mixed with (NH4)2SO4in proportion and calcined. The reaction process was studied by TG-DTA and XRD, which is that MgO in calcined boron mud reacts with (NH4)2SO4to produce (NH4)2Mg2(SO4)3at low temperature, then with increasing the temperature, (NH4)2Mg2(SO4)3decomposes into MgSO4. The effects of calcination temperature, mol ratio of reaction substrates and calcination time on conversion rate of Mg were studied. The results indicate that the conversion rate of Mg increases with the increasing of calcination temperature first then decreases, increases with the increasing of calcination time and mol ratio of (NH4)2SO4and MgO. When the calcination temperature is 500 °C, the calcination time is 3 h, the mol ratio of (NH4)2SO4and MgO is 0.9:1, the conversion rate of Mg is 81.9 %.