As a follow up to your previous answer to Dufjam, I would like some clarification about “Directional solidification”. From what I understand about directional solidification, when the metal solidifies it pushes the impurities toward the metal that is still in a liquid state, therefore, when the metal is completely solidified, you end up with an ingot that has one side purer than the other side. I'm assuming that, in order to make solar grade wafers, the less pure side of the ingot has to be cut away first. The question is, if what is said above is correct, do you expect that the less pure part of the ingot could be sold as metallurgical grade silicon, in other words, in the Purevap process, would metallurgical grade silicon be a by-product of the solar grade silicon production precess ?

Thanks !