Model Calculation And Experimental Determination Of Thermodynamic Properties Of Fe, Al, B And P Components In Silicon Melt

Solar energy will be in great demand since it is inexhaustible and cleaner than any other conventional energy resources. At present, an expensive semiconductor grade silicon (SEG-Si) is used for solar cell to convert solar energy into electricity. However, the amount of SEG-Si for solar cell supply is limited and we have to develop an innovative process for silicon production with low energy consumption in order to spread the solar cell system widely. Using relatively inexpensive metallurgical grade silicon (MG-Si) as a starting material for solar grade silicon (SOG-Si) is believed to be a promising way to produce inexpensive solar cell. But the promotion of efficiency in B removal is one of the crucial matter in the metallurgical Si refining process. For optimization or design of the B removal from Si, knowledge of the thermodynamic property of B in molten Si will be necessary to perform deeply analyses of refining techniques.In this paper, the molecular interaction volume model (MIVM) was used for a calculation of the thermodynamic properties of impurity components in dilute Si-based binary melts. Contribute to deeply investigate the removal of impurities B, Fe, Al and P, the calculation of self-interaction parameters of B(1-100ppmw), Fe(500-3000ppmw), Al (500-3000ppmw) and P(1-100ppmw)in dilute silicon melts at 1693-1873K were tried by the use of MIVM. The calculated values are presented graphically and evaluated with the reported experiment data in the literatures, which shows that the prediction effect of the Tao’s model is of stability and reliability. Furthermore, the method of MIVM is able to expand to a multicomponent Si-based melts.Otherwise, the MIVM was also used for a calculation of the properties of impurity components in Si-Fe-B, Si-Al-B ternary and Si-Fe-Al-B quaternary melts. The calculation of interaction parameters between B(l-100ppmw) and Fe(500-3000ppmw) and B(1-100ppmw) and Al (500-3000ppmw) in dilute silicon melts at 1693-1873K were obtained by the use of MIVM. Meanwhile, the activity values in the range of Al(500-1500ppmw), Fe(500-2500ppmw) andB(10-50ppmw) at 1873K were obtained. The thermodynamic properties of Si-Fe-B and Si-Al-B ternary melts were determined by the chemical equilibrium technology and saturated solubility experimental measurements at 1723K, and the interaction parameters between B and Fe, εBFe= 86.4547 and B and Al, εBAl= 4.5906 in silicon melts were obtained, respectively.