"Pure and simple" is how PHOTON Magazine described Silicor Materials process for manufacturing solar silicon.(1) One word they also could have also used to describe our process is "green".
Indeed, our manufacturing process is elegant in its use of aluminum in order to draw out impurities from silicon with a minimal environmental footprint.
How the process works
Metallurgical-grade silicon (MG-Si) is the initial feedstock to our process, just like the predominate process used in the industry known as the "Siemens" method. This metallurgical-grade silicon is 97-98% pure silicon, and by the end of our purification process, it will be over 99.9999% pure silicon. The impurities that are removed are principally boron and phosphorous.
See the illustration below to understand how Silicor Materials removes those impurities, and read our white paper for more detail.
Why the process is "green"
"Our carbon footprint is smaller, and the energy payback for our customer is higher."
Furthermore, we have lower energy requirements than other manufacturers using the traditional Siemens method. A single piece of machinery in the Siemens method, the chemical vapor deposition (CVD) reactor has historically required 100-120 kWh to produce one kilogram of solar silicon. Best-in-class vendors may have equipment whose usage is down to 45 kWh / kg. By contrast, we expect our new Mississippi facility to have a total usage of 20-30 kWh / kg.
The lower energy requirements of our process mean that our carbon footprint is smaller, and the energy payback(2) for our customers is higher.
With Silicor Materials, our process is pure and simple. And green.
(1) PHOTON Magazine, May 2009, pp. 110-113. The article was written about 6N Silicon Inc., a company that Silicor Materials acquired with its former name Calisolar Inc. in 2010.
(2) Energy payback is defined as the number of years that a PV product must be deployed in the field to "payback" the energy that was used to create it.