Preparation of calcium and magnesium hydrogen phosphates from natural dolomite and their sorptive properties
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The reaction of dolomite with 10–20% phosphoric acid was studied by x-ray diffraction and chemical analysis in a wide range of dolomite concentrations in the reaction system. The structure, composition, and sorption capacity of the reaction products were determined. The reaction was shown to yield a mixture of calcium hydrogen phosphate, CaHPO4 · 2H2O, with the brushite structure and magnesium hydrogen phosphate, MgHPO4 · 3H2O, with the newberyite structure. The sorption capacity of the reaction product for Pb ions was up to 19 mg-equiv/g. With 10% H3PO4 at an initial dolomite concentration of 0.17 g/ml, a near-theoretical reaction yield was attained.
KeywordsDolomite Sorption Capacity Magnesium Carbonate Ammonium Phosphate Magnesium Phosphate
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