铝酸钠溶液中草酸钙的行为

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Bibliographic Details
Published in中国有色金属学报：英文版 Vol. 27; no. 8; pp. 1879 - 1888
Main Author 刘桂华;董文波;齐天贵;周秋生;彭志宏;李小斌
Format Journal Article
LanguageEnglish
Published 2017
Subjects
草酸钙;铝酸钠溶液;碳酸钠;苛化;活度系数
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Bibliography:calcium oxalate; sodium aluminate solution; sodium carbonate; lime causticisation; activity coefficient
43-1239/TG
The stability of calcium oxalate is critical for the removal of sodium oxalate from sodium aluminate solutions.This studyinvestigated the behavior of calcium oxalate in sodium aluminate solution containing sodium carbonate.Results show that calciumoxalate can be converted to tricalcium aluminate hydrate(TCA)and calcium carbonate in sodium aluminate solution and sodiumcarbonate solution,respectively.Elevating temperature,extending residence time,or increasing caustic soda concentration enhancesthe conversion ratio of calcium oxalate in sodium aluminate solution;as a consequence,anti-causticisation occurs.Stability ofcalcium-containing compounds in sodium aluminate solution containing sodium carbonate differs from that in sodium aluminatesolution or sodium carbonate solution.Na2CO3in aluminate solution accelerates the transformation of calcium oxalate;thus,aluminais lost because of4CaO·Al2O3·CO2·11H2O and TCA formation.Calcium carbonate,4CaO·Al2O3·CO2·11H2O and calcium oxalatecan change into TCA in sodium aluminate solution at elevated temperature.Calcium oxalate remains relatively stable in dilutealuminate solution within a short residence time at low temperature.Thus,a novel process for removal of sodium oxalate by limecausticisation was presented and employed in an alumina refinery in China.
ISSN:1003-6326