Crystallization of high purity ammonium meta-tungstate for production of ultrapure tungsten metal
| Autor: | Choul-Ho Lee, Junhyung Kim, Cheong-Song Choi |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Supersaturation
Materials science General Chemical Engineering Diffusion Inorganic chemistry Nucleation Analytical chemistry Physics::Optics chemistry.chemical_element Crystal growth General Chemistry Tungsten law.invention Crystal chemistry.chemical_compound chemistry Tungstate law Condensed Matter::Superconductivity Crystallization |
| Zdroj: | Korean Journal of Chemical Engineering. 17:643-648 |
| ISSN: | 1975-7220 0256-1115 |
| DOI: | 10.1007/bf02699111 |
| Popis: | The growth mechanism of Ammonium Meta-Tungstate (AMT) crystal was interpreted as two-step model. Growth rates of AMT crystals were measured in a fluidized bed crystallizer. The effects of temperature, supersaturation and crystal size on the crystal growth were investigated. The contribution of the diffusion step increased with the increase of temperature, crystal size and supersaturation. The nucleation kinetics from measurements on the width of the metastable region of Ammonium Meta-Tungstate (AMT) was also evaluated. The crystal size distribution from a programmed cooling crystallization system was predicted by the numerical simulation of a mathematical model using the kinetics of nucleation and crystal growth. It was also observed that the shape of AMT crystals was changed during the growth period. |
| Databáze: | OpenAIRE |
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