A low cost, low energy route to solar grade silicon from rice hull ash (RHA), a sustainable source

Richard Laine

Julien C Marchal, David J Krug III, Patrick McDonnell, Kai Sun, and Richard M Laine (2015)

Green Chemistry, 17(7):3931-3940.

Polycrystalline silicon, with impurity levels lower than those of the SEMI III standard for solargrade silicon feedstock (≈ 99.9999% pure), was produced using rice hull ash (RHA) as abiogenic silica source. The RHA is first purified using very simple, low cost, low energy, acidmilling/boiling water wash purification steps and pelletization followed by carbothermalreduction using an experimental 50 kW electric arc furnace (EAF) operated at 1700–2100° Cin batch mode. Typical processing involves adding 3.6 kg of pellets to the EAF followed by ...

solar grade silicon, rice hull ash