首页|二氧化碳碳化沉淀制备碳酸钇的反应过程研究

二氧化碳碳化沉淀制备碳酸钇的反应过程研究

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CO2碳化沉淀制备特殊物性金属化合物粉体具有成本低、操作简单等优点,已成功应用于纳米、大比表面稀土氧化物的制备.以Y元素为研究对象,针对酸/碱体系下CO2碳化沉淀制备碳酸钇的反应过程进行研究.结果表明,氯化钇的引入会迅速与H2CO3-H2O体系中的HCO3-离子反应生成Y2(CO3)3·xH2O,从而促进H2CO3的电离,导致pH小于9.0的溶液中HCO3-的占比小于1％.在酸性体系下,CO2首先发生溶解吸收电离,然后Y3+与HCO3-反应进行沉淀,而NaOH的加入中和了反应释放出的H+,从而控制碳化体系pH;整个碳化过程符合一级反应动力学模型,由传质扩散和化学反应混合控制.在碱性体系下,Y(OH)3的转化率随着CO2通入迅速增加,然后由于碳酸钇对Y(OH)3的包裹钝化而趋于平稳,进而Y(OH)3结构坍塌碳化转化率急剧增加至完全转化.而在酸碱不同体系中,温度越高,均更易形成均相沉淀体系,有利于碳酸钇的晶型生长,获得结晶性能良好的Y2(CO3)3·2H2O.本文的研究强化了对CO2碳化沉淀碳酸钇反应过程的认识,有利于指导特殊物性稀土氧化物的均相可控及高效制备.
Reaction Procedure of Preparing Yttrium Carbonate by Carbon Dioxide Carbonization Precipitation Process
The preparation of metal compound powders with special physical properties by CO2 carbonization pre-cipitation method has the advantages of low cost and simple operation,which has been successfully used in the preparation of nanometer and large specific surface rare earth oxides.In this paper,the reaction procedure of pre-paring yttrium carbonate by carbon dioxide carbonization precipitation process in acidic/alkaline system was stud-ied,taking yttrium as a representative.The results indicate that the introduction of yttrium chloride will rapidly re-act with HCO3-in the H2CO3-H2O system to generate Y2(CO3)3·xH2O,thereby promoting the ionization of H2CO3 and resulting the proportion of HCO3-less than 1％in the solution with a pH less than 9.0.Under acidic system,carbon dioxide dissolves,absorbs and ionizes,and then Y3+reacts with HCO3-for precipitation.The added sodium hydroxide slowly neutralizes the H+released by the reaction,thereby controlling the pH of the carbonization sys-tem.The entire carbonization process conforms to the first-order reaction kinetic model,which is controlled by mass transfer diffusion and chemical reaction.Under alkaline system,the conversion rate of yttrium hydroxide in-creases with the introduction of carbon dioxide,and tends to be stable due to the encapsulation and passivation by yttrium carbonate.Then the yttrium hydroxide structure collapses,and its conversion rate increases sharply to equi-librium fully converted.In acidic/alkaline systems,the higher the temperature,the easier to form a homogeneous precipitation system,which is beneficial to the crystal growth of yttrium carbonate,and obtains Y2(CO3)3·2H2O with good crystalline properties.The research in this paper strengthens the understanding of the reaction procedure of carbon dioxide carbonization precipitation process of yttrium carbonate,which is beneficial to guiding the homo-geneous and controllable and efficient preparation of rare earth oxides with special physical properties.

carbon dioxidecarbonationyttrium carbonatereaction procedurespecies distribution

陈金发、赖安邦、何志宏、昝苗苗、卢颖、肖燕飞

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江西理工大学材料冶金化学学部,赣州市绿色冶金与过程强化工程技术研究中心,自然资源部离子型稀土资源与环境重点实验室,稀土产品检测与溯源国家市场监管重点实验室,江西赣州 341000

二氧化碳 碳化 碳酸钇 反应过程 物种分布

国冢重点研发计划江西省青年科学基金江西省双千计划科技创新高端人才(青年)项目江西省青年井冈学者奖励计划项目江西省离子型稀土资源绿色开发与高值利用国家重点实验室培育计划项目

2022YFC290520220202ACB214003jxsq2019201116QNJG201905620194AFD44003

2024

10.11785/S1000-4343.20240110

中国稀土学报
中国稀土学会 北京有色金属研究总院

中国稀土学报

CSTPCD北大核心
影响因子：1.175
ISSN：1000-4343
年,卷(期)：2024.42(1)
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