초록

The present disclosure provides devices and systems that utilize concurrent and countercurrent exchange platforms to produce purified silicon.

대표청구항 ▼

1. A device for purifying silicon comprising: a vessel having a top end, an opposing bottom end, and a plurality of concentric columns, the columns in fluid communication with each other;a central column comprising a silicon inlet at a top portion of a first column for introducing molten silicon int

1. A device for purifying silicon comprising: a vessel having a top end, an opposing bottom end, and a plurality of concentric columns, the columns in fluid communication with each other;a central column comprising a silicon inlet at a top portion of a first column for introducing molten silicon into a bed of a plurality of silica particles to form a slurry;a first channel in fluid communication with a bottom portion of the central column adapted for receiving glassy particles, which are less dense than molten silicon, by floatation thereby separating the impurity-laden glassy particles from the slurry, leaving the molten silicon, the impurity-laden glassy particles upwardly flowing in the first channel;a second channel in fluid communication with the first channel for receiving the molten silicon separated from the slurry, the silicon downwardly flowing in the second channel. 2. The device of claim 1 wherein the silica particles are fracking sand. 3. The device of claim 1 wherein the slurry comprises an additive selected from the group consisting of CaSO4 or Na2SO4, Na2O and H2O. 4. A device for purifying silicon comprising: a vessel having a top end, an opposing bottom end, and a sidewall extending between the opposing ends and defining a chamber;a silicon inlet at a top portion of the vessel for introducing silicon particles into the chamber, the silicon particles having a temperature greater than 1350° C.;an injection structure at a bottom portion of the vessel, the injection structure having at least one orifice for introducing a molten salt composition into the chamber, the molten salt composition having a temperature greater than 1350° C. and comprising an oxidizer dissolved in the molten salt,a countercurrent exchange section located between the silicon inlet and the injection structure, the countercurrent exchange section comprising(1) a controlled downward flow of the silicon particles;(2) a controlled upward flow of the molten salt composition;wherein the countercurrent flow between the downwardly flowing silicon particles and the upwardly flowing molten salt composition removes impurities at the surface of the down-flowing silicon particles and transfers them to the molten salt, purifying the silicon particles. 5. The device of claim 4 wherein the countercurrent exchange causes impurities in the silicon particles to diffuse to the silicon particle surface, the oxidizer in the molten salt oxidizes the surface impurities and the oxidized impurities are dissolved in the molten salt. 6. The device of claim 4 wherein the molten salt containing the dissolved oxidized impurities moves upwardly past the purified silicon particles. 7. The device of claim 4 wherein the purified silicon particles move downwardly through the molten salt composition to the bottom of the vessel. 8. The device of claim 4 wherein the controlled downward flow has a rate from 0.1 mm/second to 5.0 mm/second. 9. The device of claim 4 wherein the controlled upward flow has a rate from 0.1 mm/second to 20.0 mm/second. 10. The device of any claim 4 wherein the molten salt composition comprises a molten salt selected from the group consisting of molten NaCl, molten KCl, molten Al2S3, molten Na2S, molten K2S, and combinations thereof. 11. The device of claim 4 wherein the oxidizer is a sulfur-based composition selected from the group consisting of sulfur, sulfate, sulfide, and combinations thereof. 12. The device of claim 4 comprising a pump device in operative communication with the vessel for moving the molten salt composition upwardly through the vessel. 13. The device of claim 4 comprising a melting device in fluid communication with the bottom end of the vessel. 14. The device of claim 13 wherein the melting device receives the purified silicon particles from the vessel and melts the purified silicon particles to form purified molten silicon. 15. The device of claim 4 wherein the vessel is composed of graphite. 16. A device for purifying silicon by concurrent silicon-silica flow comprising: a vessel having a top end, an opposing bottom end, and a sidewall between said top end and bottom end to form a chamber;a central column extending downwards from the top end but not extending all the way to the opposing bottom end so that there is a central column end above said vessel bottom end, said central column including an inlet at its top portion for introducing molten silicon and silica particles in the form of a slurry into a packed or expanded bed of silica particles where the molten silicon and silica particles flow downward through the central column concurrently, with many height equivalent theoretical plates (HETP) contacts between the silicon and the silica particles, wherein the silica particles sorb impurities from the silicon, becoming glassy, and the silica particles remain less dense than the molten silicon;a first channel in fluid communication with the bottom portion of the central column, and a second channel in fluid communication with the bottom portion of the central column and in fluid communication with a volume above the bottom portion of the central column where the less dense particles can be collected for removal, where the impurity-laden less dense silica particles separate from the more dense molten silicon and flow into the second channel, where the impurity-laden less dense silica particles rise and collect for disposal, and where the more dense molten silicon flows from the central column into the first channel for output as a purified product. 17. The device of claim 16 wherein the mass flow of molten silicon to silica in the slurry introduced into the top of the central column is greater than 9:1. 18. The device of claim 16 wherein the silica particles are highly rounded, to minimize clumping and to maximize interstitial molten flow, after the manner of fracking sand. 19. The device of claim 16 wherein the silica particles are mixed with additive chemicals to reduce the viscosity of the silica, such as Na2O or H2O. 20. The device of claim 16 wherein the silica particles are mixed with additive chemicals that contain sulfates, such as CaSO4.