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- Title
颗粒多晶硅气泡强化脱氢机理与方法.
- Authors
吴知梁; 钱国余; 王志; 马文会
- Abstract
In order to solve the problem of high hydrogen content which is difficult to remove and harmful in granular silicon, the mechanism of bubble enhanced dehydrogenation in blowing refining process was studied by water model and high temperature refining experiment. The dehydrogenation kinetics of silicon melt was analyzed by high temperature refining dehydrogenation experiment of silicon melt without blowing. It was found that the dehydrogenation process was in accordance with the 1. 5 order kinetics model, which confirmed that dehydrogenation was llmited by mass transfer in llquid phase and reaction rate at gas--llquid interface, and provided a theoretical basis for bubble enhanced dehydrogenation. The bubble behav or was carr ed out through the water model exper ment to study the mechan sm of enhanced degassation. The results show that the bubble diameter and volumetric mass transfer coefficient increase with the increase of blowing rate. With the air blowing rate increasing from 0. 25 L/min to 1. 25 L/min, the bubble diameter mcreases from 1. 75 cm to 1. 93 cm, and the mass transfer coefficient increases from 0. 135 to 0. 337. The bubble diameter increases with the increase of blowing tube diameter, while the mass transfer coefficient decreases with the increase of blowing tube diameter. As the aperture of blowing tube increased from 3 mm to 5 mm, the diameter of bubble increased from 1. 92 cm to 2. 21 cm, and the mass transfer coefficient decreased from 0. 337 to 0. 302. With the increase of the number of blowing tubes, the diameter of bubbles produced by single tube decreases and the mass transfer coefficient decreases. As the number of blowing tubes increased from 1 to 5, the diameter of bubble decreased from 1. 46 cm to 1. 23 cm and the volumetric mass transfer coefficient increased from 0. 135 to 0. 169. And the bubbles merge when the hole distance of blowing tube is smaller than the bubble diameter, resulting in the decrease of volumetric mass transfer coefficient. Based on the bubble behavior regulation method of water model, the experiment of bubbles enhanced dehydrogenation in silicon melt under high temperature was studied. The results show that with the increase of blowing rate, hydrogen removal rate also increases. With the increase of blowing rate from 0.25 L/min to 1 L/min, the hydrogen removal rate increases from 61.41% to 71. 41%. The hydrogen removal rate decreases with the increase of blowing tube diameter. Wth the ncreaseofblowngtubedameter from 3 mm to 5 mm hydrogen removal rate decreased from 71. 15% to 68. 97%. The hydrogen removal rate increases with the increase of blowing tubes number. As the number of blowngtubes ncreases from 1 to 5 thehydrogenremovalrate ncreases from 71.15% to76.35%. When the holedstance of blowng tube slarger than 4cm the hydrogen removal rate remans about 76.35% and when the hole d stance s smal er than 4 cm the hydrogen removal rate rema ns about 72. 94%. Finally, the hydrogen content can be removed to around 4. 5X106. These results indicated that the method of bubble enhanced dehydrogenaton can achevethe depth removaloftrace hydrogen n granular polysilicon, so as to meet the requirements of solar level polysilicon.
- Subjects
MASS transfer coefficients; DEHYDROGENATION kinetics; GAS phase reactions; MASS transfer; DEHYDROGENATION
- Publication
Mining & Metallurgy (10057854), 2022, Vol 31, Issue 3, p29
- ISSN
1005-7854
- Publication type
Article
- DOI
10.3969/j.issn.1005-7854.2022.03.005