Claims
- 1. Naturally occurring quartz, which is substantially free of alkali metal impurities and which has been purified by a process which comprises (1) subjecting the quartz raw materials to a treatment which removes substantially all of the surface bound impurities to yield treated quartz crystals, which comprises two cycles of selective flotation, magnetic separation and at least one HF aqueous leach, (2) followed by subjecting the treated quartz crystals to a vapor containing HCl gas at a temperature of 800 to 1600.degree. C. to diffuse the interstitial alkali metal impurities to the surface of the treated quartz crystals to yield purified quartz crystals, and (3) recovering the purified quartz crystals.
Parent Case Info
This is a division of application Ser. No. 475,595, filed Feb. 6, 1990, now U.S. Pat. No. 4,983,370.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4804422 |
Papanikolav et al. |
Feb 1989 |
|
4818510 |
Jung |
Apr 1989 |
|
Foreign Referenced Citations (4)
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671691 |
Oct 1965 |
BEX |
0130808 |
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EPX |
0156342 |
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Divisions (1)
|
Number |
Date |
Country |
Parent |
475595 |
Feb 1990 |
|