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为解决传统次碳酸铋生产过程中成本高和环境污染问题,提出采用液相球磨法由氧化铋制备次碳酸铋的新工艺,研究用碳酸氢氨和氧化铋制备次碳酸铋反应过程的动力学,考察反应温度、氧化铋粒度、液固比以及碳酸氢氨浓度对氧化铋转化率的影响。结果表明,在9~30°C的范围内,升高反应温度、减小氧化铋粉末的粒度、扩大液固比以及提高碳酸氢氨浓度均有利于氧化铋转化率的提高。对反应产物的表征分析表明,产品的纯度较高、杂质少;SEM结果显示产品次碳酸铋主要呈针棒状形态。反应过程受产物层的扩散控制,可用未反应收缩核模型描述,反应的表观活化能为9.783 kJ/mol,同时获得了描述反应过程的半经验动力学方程。
In order to solve the problem of high cost and environmental pollution in the traditional bismuth subcarbonate production process, a new process of preparing bismuth subcarbonate from bismuth oxide by liquid-phase ball milling was proposed. The kinetics of the reaction process of preparing bismuth subcarbonate with ammonium bicarbonate and bismuth oxide The effects of reaction temperature, particle size of bismuth oxide, liquid to solid ratio and ammonia bicarbonate concentration on the conversion of bismuth oxide were investigated. The results showed that increasing the reaction temperature, decreasing the particle size of bismuth oxide powder, expanding the liquid / solid ratio and increasing the concentration of ammonia bicarbonate all contributed to the increase of the bismuth oxide conversion within the range of 9-30 ° C. The characterization of the reaction product showed that the purity of the product was high and the impurities were few. The SEM results showed that the bismuth subcarbonate was mainly in the form of needle and rod. The reaction process is controlled by the diffusion of the product layer and can be described by the unreacted core model. The apparent activation energy of the reaction is 9.783 kJ / mol, and the semi-empirical kinetic equation describing the reaction process is obtained.