Analytical Grade Magnesia Lab Report

2. Materials and Methods
2.1. Materials Analytical grade magnesia (98.0 wt.%, 1.5 wt% carbonate; Sinopharm Chem. Reagent Co. Ltd., China), analytical grade ammonium chloride (99.5 wt.%, Xilong Chem. Co. Ltd., China), analytical grade potassium chloride (99.5 wt.%, Xilong Chem. Co. Ltd., China), analytical grade sodium chloride (99.5 wt.%, Xilong Chem. Co. Ltd., China), and analytical grade calcium chloride (96.0 wt.%, Xilong Chem. Co. Ltd., China) were used for the experiments.
2.2. Preparation of high-purity anhydrous KMgCl3 Anhydrous KMgCl3 was prepared by using magnesia, potassium chloride and ammonium chloride as raw materials. Magnesia, potassium chloride and ammonium chloride with a certain molar ratio were mixed evenly by grinding.

Details on the preparation of anhydrous MgCl2 have been described previously [13]. 17.8 g anhydrous KMgCl3 and 10 g anhydrous MgCl2 (the molar ratio of KMgCl3:MgCl2 was 1:1) were maintained at room temperature and 450 oC in constant temperature and humidity chamber for different times, respectively. Then the products obtained were used for analysis. The hygroscopy at room temperature could be reflected by the weight increase of the sample, and the hygroscopy at 450 oC could be reflected by w(MgO)/w(MgCl2) of the sample.
2.4. Electrolytic properties of anhydrous KMgCl3 To investigate the electrolytic properties of anhydrous KMgCl3, we prepared magnesium metal from anhydrous KMgCl3 by electrochemical method. The electrolytic properties were reflected by various parameters in the electrolytic process. Electrolysis cell: graphite crucible (Ø 65 mm×140 mm); cathode: steel rod (d=6 mm); anode: spectrally pure graphite rod (d=6 mm); electrolytic temperature: 700 oC; electrolyte: KCl-KMgCl3-NaCl-CaCl2 (15:32:38:15 wt.%); electrolytic time: 4 h; inter-electrode distance: 4 cm; cathodic current density: 0.50