Claims
- 1. A method of purifying natural or synthetic silica in which a plasma is fed by a first feed duct with grains of natural or synthetic silica,wherein a second feed duct feeds the plasma with a fluorine or chlorine compound mixed with a carrier gas, the feed conditions of the two ducts are adjusted to cause alkali or alkaline-earth elements contained in the natural or synthetic silica grains to react with the fluorine or the chlorine of the fluorine or chlorine compound, causing fluorides or chlorides to be given off in gaseous form, wherein the second feed duct is positioned entirely external to a supply source for the plasma, wherein the grains of natural or synthetic silica and the fluorine or chlorine compound are both supplied externally and directly to the plasma at an end of the supply source.
- 2. A method according to claim 1, wherein the fluorine or chlorine compound is a fluorine compound.
- 3. The method according to claim 1, in which the plasma is at a temperature greater than 5,000° C.
Priority Claims (1)
Number |
Date |
Country |
Kind |
97 03519 |
Mar 1997 |
FR |
|
Parent Case Info
This is a continuation of application Ser. No. 09/035,146 filed Mar. 5, 1998 now U.S. Pat. No. 6,477,864, the entire disclosure of which is incorporated herein by reference.
US Referenced Citations (10)
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DE |
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Non-Patent Literature Citations (1)
Entry |
Carratt, et al., “MCVD-Plasma Process for Manufacturing Single-mode Optical Fibers for Terrestrial Applications,” 1225 Electrical Communication, 1st Quarter 1994, pp. 11-14, Paris, France. |
Continuations (1)
|
Number |
Date |
Country |
Parent |
09/035146 |
Mar 1998 |
US |
Child |
10/247616 |
|
US |