Lithium Containing Glass with High Oxidized Iron Content and Method of Making Same

Patent metadata

Field	Value
Publication number	US-2020283330-A1
Application number	US-202016781567-A
Country	US
Kind code	A1
Filing date	Feb 4, 2020
Priority date	Feb 24, 2012
Publication date	Sep 10, 2020
Grant date	—

Abstract

A low infrared absorbing lithium glass includes FeO in the range of 0.0005-0.015 wt %, more preferably 0.001-0.010 wt %, and a redox ratio in the range of 0.005-0.15, more preferably in the range of 0.005-010. The glass can be chemically tempered and used to provide a ballistic viewing cover for night vision goggles or scope. A method is provided to change a glass making process from making a high infrared absorbing lithium glass having FeO in the range of 0.02 to 0.04 wt % and a redox ratio in the range of 0.2 to 0.4 to the low infrared absorbing lithium glass by adding additional oxidizers to the batch materials. A second method is provided to change a glass making process from making a low infrared absorbing lithium glass to the high infrared absorbing lithium glass by adding additional reducers to the batch material. In one embodiment of the invention the oxidizer is CeO 2 . An embodiment of the invention covers a glass made according to the method.

First claim

What is claimed is:

1 . A method of changing molten glass in a furnace from a molten low infrared absorbing glass composition having FeO in the range of 0.0005 to 0.015 wt %, and a redox ratio in the range of 0.005 to 0.15 to a high infrared absorbing glass composition having FeO in the range of 0.02 to 0.05 wt % and a redox ratio in the range of 0.2 to 0.4, comprising:
feeding low infrared absorbing glass batch material and a predetermined amount of a first reducing agent to increase the FeO to provide the molten high infrared absorbing glass composition; and ceasing the practice of the preceding step after a predetermined period of time.

2 . The method according to claim 1 , wherein after the step of feeding the glass batch material, the method further comprises adding a second reducing agent to the low infrared absorbing glass batch material in an amount in the range of one to two times the amount of the first reducing agent for a predetermined period of time to increase the FeO in the molten glass in the furnace.

3 . The method according to claim 1 , wherein the first reducing agent comprises elemental carbon, graphite, sucrose, coal, elemental silicon and/or tin oxide.

4 . The method according to claim 2 , wherein the reducing agent comprises elemental carbon, graphite, sucrose, coal, elemental silicon and/or tin oxide.

Assignees

• Ppg Ind Ohio Inc

Inventors

• Goodwin George B
• Arbab Mehran
• Harris Caroline S
• Shelestak Larry J

Classifications

• C03C21/002

  to perform ion-exchange between alkali ions (C03C21/005 takes precedence) · CPC title

• B32B17/10045

  with at least one intermediate layer consisting of a glass sheet · CPC title

• C03C3/083 Primary

  containing aluminium oxide or an iron compound · CPC title

• B32B2605/08

  Cars · CPC title

• C03B5/16

  Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces · CPC title