Quartz fusion furnace and method for forming quartz articles

A furnace for melting silica for fusion into a desired shape, said furnace comprising a body forming a chamber having a generally vertically oriented longitudinal axis, said chamber including at least an upper melting zone and a lower drawing zone, said melting zone comprised of a first layer of a refractory material and a barrier layer comprised of a protective material selected from rhenium, osmium, iridium, and mixtures thereof disposed on an inner surface of said first layer, said barrier layer extending at least from below a melt line to a top and side walls of the chamber, said barrier layer forming a substantially gas-tight atmosphere in said melting zone, and a silica feed member through said wall and into a top portion of said melting zone, said feed member forming a gas-tight seal with said barrier layer.

A continuous method of forming an elongated fuse quartz member which comprises:

• a) continuously feeding a generally SiO2 raw material in particulate form into an induction heated furnace, said furnace including a gas-tight inner surface comprised of a material selected from rhenium, osmium, iridium and mixtures thereof,
• b) fusing said raw material continuously in the furnace being supplied with an inert gas atmosphere while maintaining a fusion temperature, and,
• c) drawing the fused material continuously from furnace.