US 12,338,127 B2
Method for refining crude silicon melts using a particulate mediator
Karl-Heinz Rimböck, Heldenstein (DE); and Konrad Mautner, Burghausen (DE)
Assigned to Wacker Chemie AG, Munich (DE)
Appl. No. 17/607,888
Filed by Wacker Chemie AG, Munich (DE)
PCT Filed Apr. 30, 2019, PCT No. PCT/EP2019/061048
§ 371(c)(1), (2) Date Oct. 31, 2021,
PCT Pub. No. WO2020/221440, PCT Pub. Date Nov. 5, 2020.
Prior Publication US 2022/0219994 A1, Jul. 14, 2022
Int. Cl. C01B 33/037 (2006.01)
CPC C01B 33/037 (2013.01) [C01P 2004/60 (2013.01)] 11 Claims
 
1. A process for oxidatively refining crude molten silicon in the production of technical silicon, comprising:
admixing the crude molten silicon during refining with a particulate mediator which comprises a minimum amount of metallic silicon of 8% by mass and at least one or more of the elements H, C, O, F, Cl, Ca, Fe and Al, wherein the particulate mediator is described by a characteristic number K which has a value of 0.03 to 6 mm-1 and is calculated as follows:

OG Complex Work Unit Math
wherein d50,M is the particle size (diameter) at 50% of the mass undersize of the grading curve of the particulate mediator [mm]; and
wherein εm,M is the mean effective porosity of the particulate mediator.