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US 8,709,370 B2Granted
Method and system for producing fluoride gas and fluorine-doped glass or ceramics
AssigneeSRI International
InventorsAngel Sanjurjo, Kai-Hung Lau, Xiaobing Xie, Gopala Krishnan
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Abstract
The present invention relates generally to production of a fluoride gas and equivalents thereof, and fluorine-doped sodium silicate glass, glass ceramics, vitro ceramics and equivalents thereof. In one embodiment, the method includes providing a salt and an oxide in a reactor, heating the reactor to produce a vapor and the vitro ceramic and removing the vapor.
Claims3
A method for producing sodium silicate glass during a production of a high purity silicon (Si), comprising:
- precipitating sodium fluorosilicate (Na2SiF6) from fluorosilicic acid (H2SiF6);
- thermally decomposing the Na2SiF6 to produce a silicon tetrafluoride gas (SiF4) and sodium fluoride (NaF);
- reducing the SiF4 with sodium (Na) to produce NaF and the high purity Si in a first reactor;
- providing the NaF from the reduction of the SiF4 from the first reactor and silica sand (SiO2) in a second reactor;
- and
- heating the second reactor to produce additional SiF4 and the sodium silicate glass doped with fluorine ions (Na2SiO3(F)), wherein the heating comprises providing energy released from the first reactor in an exothermic reaction of the SiF4 that is reduced with the Na;
- purifying the additional SiF4 via a condenser absorber train;
- and
- recycling the additional SiF4 back into the reducing step.
6 more elements
Dependencies are inferred from the claim text.