Effect of Channel Type Reactor for Efficient Extraction of B for Production of High Purity Silica

抄録

As a part of new preparation process for solar grade silicon manufacturing, the present study focuses on eliminating a lighter element impurity, boron（B）, from silica solution using channel type reactors for liquid-liquid extraction process. Because B determines the semiconductor properties of silicon if included and so should be removed precisely. The boric acid solution is used as a model solution and 2,2,4-trimethyl-1,3-pentanediol（TMPD）as an extractant for extraction process. The model reactor with obstacles inside the channel was tried to fabricate with a 3D printer commercially available. The Y-shaped channel with converging-diverging and obstacles type reactor resulted in maximum extraction efficiency. This reactor had higher surface/volume ratio and two distinct characteristic structures at interfacial area leads to continuous droplet formation, which also enhanced the mass transfer efficiencies of boric acid and TMPD molecules. Then after, the refined silica with ppm level of boric acid solution was similarly introduced to the channel reactor, which resulted in 99.7% of extraction efficiency of B. Therefore, it was found that this kind of channel reactor was suitable for efficient mixing of different phases and increasing the extraction efficiency.