High purity magnesium comparison-gas volumetric determination of calcium or magnesium in steelmaking auxiliary materials

A high purity magnesium comparison-gas volumetric method for the determination of magnesium in passivated magnesium desulfurizer and calcium in calcium-iron cored wire for steelmaking was proposed.Dilute hydrochloric acid and ammonium chloride solution were used to dissolve passivated magnesium desulfurizer and calcium-iron cored wire samples respectively,during which magnesium and calcium in the samples reacted with hydrogen ions in the solvent,releasing equivalent amount of hydrogen.The volume of the generated hydrogen was determined by self-made drainage device.Under the same temperature and pressure,the highly pure magnesium standard sample was dissolved with solvent and the volume of the generated hydrogen was determined.Based on gas state equation,the content of magnesium in passivated magnesium desulfurizer and calcium in calcium-iron cored wire was worked out with comparison method.The proposed method was applied to the determination of magnesium in passivated magnesium desulfurizer,whose results were consistent with those by iodine-ethyl alcohol extraction-EDTA complex titrimetry with relative standard deviation(RSD,n=6)less than 0.3%.The method was applied to determine calcium in calcium-iron cored wire with RSD(n=6)less than 1.8%and recovery of 98%-99%.