Rapid Determination of Calcium and Magnesium in Ore by EDTA Complexometric Titration.

The sample was decomposed by hydrochloric acid, nitric acid, hydrofluoric acid and perchloric acid, and at pH = 6-9, Fe, Al, Cr, Ti, Ag, Hg, Bi, Ni, Co, Pb, Zn, Cu, Cd and Mn were separated by hexamethylenetetramine-copper reagent. Calcium and magnesium were determined by EDTA complexometric titration in ammonia solution of pH = 10 and ammonium chloride buffer solution of ammonia chlorideasacid chromium blue K-naphthol green Bas indicator; orcalcium was determined by EDTA complexometric titration in potassium hydroxide solution with calcium reagent as indicator. The content of magnesium or calcium (< 5%) with low content can be accurately determined by ICP-AES when the sample is high in calcium and low in magnesium or high in magnesium and low in calcium. Calcium and magnesium in three standard samples were determined by this method. The results were in agreement with the certified values. The relative standard deviation was between 0.69% and 1.3% (n = 7), and the recovery was between 99% and 102%. This method is practical and has been successfully applied to the determination of calcium and magnesium in various ores. [ABSTRACT FROM AUTHOR]