Glass manufacturing method using electric melting

Patent metadata

Field	Value
Publication number	US-10000404-B2
Application number	US-201314654189-A
Country	US
Kind code	B2
Filing date	Dec 20, 2013
Priority date	Dec 21, 2012
Publication date	Jun 19, 2018
Grant date	Jun 19, 2018

Abstract

One subject of the invention is a process for manufacturing a glass, the chemical composition of which comprises at least 3% by weight of iron oxide, expressed in the form Fe 2 O 3 , comprising a step of electric melting, using electrodes submerged in the molten glass, of a vitrifiable batch material mixture containing at least one manganese carrier wherein the manganese is in an oxidation state higher than +2.

First claim

The invention claimed is:

1. A process for manufacturing a glass comprising from 3-15% by weight of iron oxide, expressed in the form Fe 2 O 3 , the process comprising:
electric melting, with electrodes submerged in a molten glass, of a vitrifiable batch material mixture comprising at least one manganese carrier in which manganese is in an oxidation state higher than +2,
wherein the glass comprises, by weight percentages:

SiO 2
35-55%;

Al 2 O 3
14-27%;

CaO
12-16%;

MgO
 0-6%;

Na 2 O + K 2 O
 1-17%;

B 2 O 3
 0-8%;

P 2 O 5
 0-3%; and

TiO 2
 0-2%, and

wherein the glass comprises a combined content of CaO and MgO in the range of 14 to 18% by weight.

2. The process of claim 1 , wherein the at least one manganese carrier is selected from MnO 2 , Mn 3 O 4 , Mn 2 O 3 , Mn 2 O 7 , a permanganate, or any mixture thereof.

3. The process of claim 1 , wherein a total amount of manganese carrier contained in the vitrifiable batch material mixture is such that one ton of a dry mixture thereof comprises an amount ranging from 1 to 20 kg of manganese in an oxidation state higher than +2, expressed in the form MnO 2 .

4. The process of claim 1 , wherein the at least one manganese carrier is selected from Mn 3 O 4 , Mn 2 O 3 , Mn 2 O 7 , a permanganate, or any mixture thereof.

5. The process of claim 1 , wherein the at least one manganese carrier is Mn 2 O 3 .

6. The process of claim 1 , wherein a total amount of manganese carrier contained in the vitrifiable batch material mixture is such that one ton of a dry mixture thereof comprises an amount ranging from 2 to 10 kg of manganese in an oxidation state higher than +2, expressed in the form MnO 2 .

7. The process of claim 1 , wherein a total amount of manganese carrier contained in the vitrifiable batch material mixture is such that one ton of a dry mixture thereof comprises an amount ranging from 4 to 8 kg of manganese in an oxidation state higher than +2, expressed in the form MnO 2 .

8. The process of claim 1 , wherein the glass composition comprises at least 0.3% by weight of manganese oxide, expressed in the form MnO 2 .

9. The process of claim 1 , wherein the vitrifiable mixture contains no nitrate.

10. The process of claim 1 , wherein the glass comprises a combined content of CaO and MgO in the range of 15 to 18% by weight.

11. The process of claim 1 , wherein the electrodes comprise molybdenum.

12. The process of claim 1 , wherein the electrodes comprise tin oxide.

13. The process of claim 1 , wherein during the melting the temperature of the molten glass, measured in contact with tank refractories and at a hottest point, ranges from 1400° C. to 1650° C.

14. The process of claim 1 , wherein after the melting the molten glass is formed into mineral wool during a fiberizing step.

Assignees

• Saint Gobain Isover

Inventors

• Clatot Richard
• Maugendre Stéphane

Classifications

• C03C3/091

  containing aluminium · CPC title

• C03C13/06 Primary

  Mineral fibres, e.g. slag wool, mineral wool, rock wool · CPC title

• C03B5/027 Primary

  by passing an electric current between electrodes immersed in the glass bath, i.e. by direct resistance heating · CPC title

• C03C3/087

  containing calcium oxide, e.g. common sheet or container glass · CPC title

• C03C3/097

  containing phosphorus, niobium or tantalum · CPC title