Abstract：The reason of error arising was examined in the determination of Mg(OH)Cl and MgO in bischofite dehydration product by indirect method, in which the impurity content of Mg(OH)Cl and MgO in bischofite dehydration was obtained by subtraction method after the major component was determined by EDTA titrimetric method. Two direct determination methods were proposed. Firstly, total MgO was obtained by using EDTA titration for determining the magnesium in aqueous-soluble residue of bischofite dehydration product(direct method A). Secondly, Mg(OH)Cl and MgO were obtained by simultaneous determination of magnesium in alcohol-soluble residue and the aqueous residue of dehydration product(direct method B). Magnesium in alcohol or aqueous residue was titratd by EDTA after the residue was dissolved in boiled 5%(V/V)H2SO4. The experiment indicated the absolute error for the determination of total magnesium oxide in dehydration product by direct method was quite small (with mass fraction of less than 0.1%). Among both methods, the direct method A which was used for determining total magnesium oxide in dehydration product was more stable and reliable, with high precision and accuracy (the recoveries were 94%-117%). Therefore, direct method A is more suitable for the accurate determination of total MgO in bischofite dehydration which was obtained by using C6H5NH2·HCl as dehydrating agent.
胡湖生，杨明德，吴玉龙. EDTA滴定法直接测定水氯镁石脱水产品中氧化镁[J]. 冶金分析, 2013, 33(5): 27-31.
HU Hu-sheng,YANG Ming-de,WU Yu-long. Direct determination of magnesium oxide in dehydration products of bischofite by EDTA titrimetric method. , 2013, 33(5): 27-31.
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