The research was mainly based on the formation condition of crystalline ammoniu yttrium carbonate and the variation characteristics of PH value during the crystallization in which NH4HCO3 was used to precipitate yt...The research was mainly based on the formation condition of crystalline ammoniu yttrium carbonate and the variation characteristics of PH value during the crystallization in which NH4HCO3 was used to precipitate yttrium ion. It is found that the crystallization process is always associated with the descent of pH. The pH of solution is controlled by the crystallization reaction of ammonium yttrium carbonate and the hydrolysis of NH4HCO3. Based on the pH variation, it can be judged whether the crystallization reaction occurs or not and the speed and the degree of crystallinity can be deterolfned. The precipitates were characterized by X- ray powder diffraction and differential thermal -thermogravimetric analysis. The results show that the crystallization is the process of NH4Y(CO3)2 formation and it is effected by feed ratio and feed method.展开更多
The aggregation kinetics of basic yttrium carbonate pericles in aqueous solution havebeen studied using dynamic light-scattering techniques. In 1.00mol/l NaCl solution fast diffusionlimited aggregation behavior was ob...The aggregation kinetics of basic yttrium carbonate pericles in aqueous solution havebeen studied using dynamic light-scattering techniques. In 1.00mol/l NaCl solution fast diffusionlimited aggregation behavior was observed with an increase in aggregate size over time describedby a power law. The aggregates are characterized by a fractal dimension D=1.82. Smoluchowskiand fractal theories were used to characterize the aggregation mechanism and to obtain theaggregation rate constant.展开更多
文摘The research was mainly based on the formation condition of crystalline ammoniu yttrium carbonate and the variation characteristics of PH value during the crystallization in which NH4HCO3 was used to precipitate yttrium ion. It is found that the crystallization process is always associated with the descent of pH. The pH of solution is controlled by the crystallization reaction of ammonium yttrium carbonate and the hydrolysis of NH4HCO3. Based on the pH variation, it can be judged whether the crystallization reaction occurs or not and the speed and the degree of crystallinity can be deterolfned. The precipitates were characterized by X- ray powder diffraction and differential thermal -thermogravimetric analysis. The results show that the crystallization is the process of NH4Y(CO3)2 formation and it is effected by feed ratio and feed method.
文摘The aggregation kinetics of basic yttrium carbonate pericles in aqueous solution havebeen studied using dynamic light-scattering techniques. In 1.00mol/l NaCl solution fast diffusionlimited aggregation behavior was observed with an increase in aggregate size over time describedby a power law. The aggregates are characterized by a fractal dimension D=1.82. Smoluchowskiand fractal theories were used to characterize the aggregation mechanism and to obtain theaggregation rate constant.
