摘要
在热力学计算的基础上,研究CaCO3在铝酸钠溶液体系中发生反苛化反应的规律。热力学计算表明,低温条件下,CaCO3与游离苛性碱形成Ca(OH)2的反苛化程度较小,而其与Al(OH)4-形成3CaO.Al2O3.6H2O(C3AH6)的反苛化反应显著。CaCO3在纯NaOH溶液中反苛化反应的反应率小于5%,而在铝酸钠溶液中其反苛化率可达50%以上,说明Al(OH)4-对CaCO3的反苛化具有显著的促进作用;CaCO3的反苛化率随温度的升高而升高,随铝酸钠溶液苛性比αk的升高呈先升高后降低的规律,当αk为3时,出现极大值;常压条件下,CaCO3在铝酸钠溶液中发生反苛化反应形成C3AH6,而造成氧化铝损失。
Anti-causticization of calcium carbonate in sodium aluminate solution was studied.The thermodynamic calculation result shows that the degree of anti-causticization reaction of CaCO3with NaOH solution to form Ca(OH)2is low at low temperatures,while that of CaCO3 with Al(OH)4- to form 3CaO.Al2O3.6H2O(C3AH6) is significant.The reaction rate of CaCO3is less than 5% in pure sodium hydroxide solution and more than 50% in sodium aluminate solution,indicating that Al(OH)4- anion can significantly promote the anti-causticization of calcium carbonate in sodium aluminate solution.The reaction rate of anti-causticization improves with the increase of temperature,increasing first and then decreasing with the increase of the mole ratio of Na2O to Al2O3(αk),and reaches the maximum with αk of approximate 3.The results also show that C3AH6is formed in the anti-causticization of CaCO3 in sodium aluminate solution under the atmospheric condition,causing the loss of alumina.
出处
《中南大学学报(自然科学版)》
EI
CAS
CSCD
北大核心
2013年第7期2663-2668,共6页
Journal of Central South University:Science and Technology
基金
中央高校基本科研业务费专项资金资助(2010QZZD004)