This Small Business Innovation Research (SBIR) Phase I project will develop a process to convert renewable agricultural byproducts to solar grade silicon metal in an energy efficient and environmentally friendly manner. The hulls of rice and many other grain plants are rich in silica derived from the soil in which they are grown. This silica can be extracted in a highly purified form from rice hull ash to produce useful specialty chemicals. It can also be extracted to provide a basic feedstock for the production of solar grade silicon for the production of photovoltaic cells. This process will bypass the capital and energy intensive methods, such as the Siemens process, which are currently in use.
The broader impact/commercial potential from this technology could develop a process which will enable the production of high purity silicon directly from agricultural byproducts without the use of the current energy intensive methods such as the Siemens process. The process uses an abundant waste product as a renewable material source in an energy-efficient manner to achieve a valuable product at low cost and with minimal environmental impact. Current production of crystalline photovoltaic cells is limited by the bottleneck of poly-silicon production. This innovative new process will enable downstream PV plants to run at full capacity, unconstrained by shortages of raw material, thus allowing more rapid adoption of solar energy at lower cost per kWp. Furthermore, the proposed process will be better for the environment in that it is much less energy intensive and uses less toxic chemicals than existing methods.
