Title: Preparation of high-purity calcium oxide from salt lake by-product calcium sulfate by conversion method
Abstract: The precursor of CaO was prepared by the conversion reaction between salt lake by-product CaSO4·2H2O and NH4HCO3 solution.And then high purity CaO was prepared by pyrolyzing.The effects of mole ratio of NH4HCO3 to CaSO4·2H2O,reaction time and temperature on the conversion rate were investigated respectively.The products were analyzed by XRD and chemical analytical method.The kinetic analysis of the conversion reaction process was made.The results show that the conversion rate of CaSO4·2H2O can reach 99.6% under the conditions of mole ratio 1.3:1.0,reaction time 2.5 h and temperature 50 ℃.The CaO with purity of 99.7% can be prepared by the pyrolysis of solid product at 1 000 ℃ for 1 h.The kinetic analysis demonstrates that the conversion process is in accordance with shrinking core model,which is expressed as a mathematical formula of kt=1-(1-X)1/3 and the apparent activation energy is 43.4 kJ/mol.The model indicates that the conversion process is controlled by the interface chemical reaction process.
Publication Year: 2012
Publication Date: 2012-01-01
Language: en
Type: article
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