GB2471335A

GB2471335A - Glass Feedstock

Info

Publication number: GB2471335A
Application number: GB0911133A
Authority: GB
Inventors: James Mcbride
Original assignee: Viridor Waste Management Ltd
Current assignee: Viridor Waste Management Ltd
Priority date: 2009-06-26
Filing date: 2009-06-26
Publication date: 2010-12-29
Anticipated expiration: 2029-06-26
Also published as: GB0911133D0; GB2471335B

Abstract

A process for producing a glass product is disclosed which comprises feeding glass comprising boron to a furnace and feeding otherglass to the furnace. The glass comprising boron comprises glass from a cathode ray tube. The feedstock may further contain an additive comprising borax or boron oxide.

Description

S

Glass Feedstock

Background of the Invention

The present invention concerns a process for producing a glass product. The invention also concerns a process for producing a glass feedstock. The invention also concerns a glass feedstock. The invention also concerns a process for producing fibreglass.

Glass feedstocks are used in a number of industries.

Glass feedstocks may, for example, be produced from newly formed glass or from waste glass. Many countries collect waste glass and redundant devices comprising glass at recycling facilities and other sites and such glass may be used for the formation of glass feedstocks.

In certain industries the chemical composition of a glass feedstock may be important and the glass may require one or more chemicals to be added to it, especially if the glass is waste glass. For example, in the fibreglass manufacturing industry, it may be necessary to add boron in some form to the glass.

Prior art processes have added boron, or boron

containing compounds, during preparation of the glass feedstock. Boron, or boron containing compounds, may be expensive and may contribute a significant amount to the cost of the glass feedstock.

The present invention seeks to mitigate some of the above-mentioned problems.

Summary of the Invention

According to a first aspect of the invention, there is provided a process for producing a glass product, wherein the process comprises feeding glass comprising boron to a furnace and feeding other glass to the furnace.

The glass comprising boron may be fed to the furnace separately to the other glass. The glass comprising boron may be mixed with the other glass prior to being fed to the furnace.

The phrase "glass comprising boron" as used herein will be understood to mean glass which includes at least some boron. For example, the glass comprising boron may be borosilicate glass. The boron included in the glass may be elemental boron, or it may be boron as part of a boron containing compound, for example boric oxide.

Preferably the glass comprising boron comprises at least 1% boron by mass. More preferably, the glass comprising boron comprises at least 2% boron by mass. Yet more preferably, the glass comprising boron comprises at least 5% boron by mass. Even more preferably, the glass comprising boron comprises at least 10% boron by mass.

Still more preferably, the glass comprising boron comprises at least 15% boron by mass. It will be understood that the boron may be present as part of a boron containing compound, for example boric oxide (8203) or borax.

The glass comprising boron may, for example, comprise glass from a cathode ray tube (CRT) . Cathode ray tubes are well known in the art. They are used, for example, in some television screens, some computer monitors and some scientific instruments. The glass comprising boron may, for example, be obtained from TVs, from computer monitors, or from scientific instruments.

CRTs may include a funnel portion and a screen panel.

The funnel portion may be made from a glass comprising lead.

The screen panel may be the part of the CRT that is visible to a user who views an image on the CRT. Advantageously, the glass comprising boron comprises glass from a CRT screen panel. The screen panel may include boron. The boron may be in the form of boron containing compounds. The process may include the step of separating the screen panel from other parts of the CRT. The separating may be done manually.

The process may include the step of breaking the glass comprising boron into a multiplicity of pieces. Preferably the pieces have a maximum dimension of 18 mm, more preferably the pieces have a maximum dimension of 12 mm, yet more preferably the pieces have a maximum dimension of 6 mm.

The other glass may comprise waste glass. The waste glass, or a device including the waste glass, may have been discarded. For example, the waste glass may. be glass collected for recycling. The waste glass may be bottle glass. The waste glass may be plate or panel glass from manufacturing waste or post consumer commercial recovery.

The other glass may comprise new glass. New glass may be understood to be glass that has not been previously used in a device. That is it may be glass that has been produced from raw materials.

The other glass may consist substantially entirely of waste glass. Alternatively the other glass may consist substantially entirely of new glass. Another possibility is that the other glass may consist of a mixture of waste glass and new glass.

The ratio of the glass comprising boron and the other glass fed to the furnace may be from about 1:1 to about 1:20 by mass. Preferably the ratio of the glass comprising boron and the other glass fed to the furnace is from about 1:1 to about 1:10 by mass. More preferably the ratio of the glass comprising boron and the other glass fed to the furnace is from about 1:1 to about 1:5 by mass.

The process may include the step of adding an additive into the furnace. The additive may comprise a non-glass additive. For example, the additive may comprise boron or a boron containing compound. The additive may comprise borax.

The additive may comprise boric oxide. The additive may be added directly to the furnace. The additive may be mixed with the glass comprising boron, or the other glass, or both, prior to being added to the furnace.

The process may include the step of screening the glass comprising boron. Preferably the screen size is not more than 18 mm. More preferably the sóreen size is not more than 12 mm. Yet more preferably the screen size is not more than 6 mm.

According to a second aspect of the invention, there is provided a process for producing a glass feedstock, wherein the process comprises mixing glass comprising boron with other glass.

Preferably the glass comprising boron comprises at least 1 boron by mass. More preferably, the glass comprising boron comprises at least 2% boron by mass. Yet more preferably, the glass comprising boron comprises at least 5% boron by mass. Even more preferably, the glass comprising boron comprises at least 10% boron by mass.

Still more preferably, the glass comprising boron comprises at least 15% boron by mass. It will be understood that the boron may be present as part of a boron containing compound,.

for example boric oxide (B203) . The glass comprising boron may, for example, comprise glass from cathode ray tube (CRT) screen panels.

The process may include the step of breaking the screen panel into a multiplicity of pieces. Preferably the pieces have a maximum dimension of 18 mm, more preferably the pieces have a maximum dimension of 12 mm, yet more preferably the pieces have a maximum dimension of 6 mm.

The process may include the step of adding an additive to the glass feedstock. The additive may comprise a non-glass additive. For example, the additive may comprise boron or a boron containing compound. The additive may comprise borax.

The process may include the step of screening the glass feedstock. Preferably the screen size is not more than 18 mm. More preferably the screen size is not more than 12 mm.

Yet more preferably the screen size is not more than 6 mm.

The glass product may be fibreglass.

ccording to a third aspect of the invention there is provided a glass feedstock, wherein the feedstock includes a mixture of glass comprising boron and other glass.

Still more preferably, the glass comprising boron comprises at least 15% boron by mass. It will be understood that the boron may be present as part of a boron containing compound, for example boric oxide (B203) . The glass comprising boron may, for example, comprise glass from cathode ray tube (CRT) screen panels.

The glass feedstock may have a boron content from about 4% to about 30% by mass. Preferably the glass feedstock has a boron content from about 4% to about 16% by mass. More preferably the glass feedstock has a boron content from about 8% to about 12% by mass. Such a glass feedstock may be suitable for use in the manufacture of fibreglass.

The glass feedstock may further include an additive.

The additive may comprise a non-glass additive. For example, the additive may comprise boron or a boron containing compound. The additive may comprise borax. The additive may comprise boric oxide.

The glass feedstock may be a crushed glass feedstock.

The glass feedstock may comprise a multiplicity of glass particles. The particles may have a maximum dimension of no greater than about 18 mm. Preferably the particles have a maximum dimension of no greater than about 12 mm. More preferably the particles have a maximum dimension of no greater than about 6 mm.

The glass feedstock may be sized such that is passable through a screen having a screen size of not more than 18 mm. More preferably the screen size is not more than 12 mm.

Yet more preferably the screen size is not more than 6 mm.

The screen size may comprise a mesh and the screen size may be the size of the holes defined by the mesh.

The mixture may contain glass comprising boron and other glass in a ratio from about 1:1 to about 1:20 by mass.

Preferably the mixture contains glass comprising boron and other glass in a ratio from about 1:1 to about 1:10 by mass.

More preferably the mixture contains glass comprising boron and other glass in a ratio from about 1:1 to about 1:5 by mass.

According to a fourth aspect of the invention there is provided a process of producing fibreglass, wherein the process comprises the step of mixing glass comprising boron with other glass.

It will of course be appreciated that features described in relation to one aspect of the present invention may be incorporated into other aspects of the present invention. For example, a process of the invention may incorporate any of the features described with reference to the glass feedstock of the invention and vice versa.

Description of the Drawings

Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings of which: Figure 1 is a schematic representation in block diagram form of a process for producing a glass feedstock; and Figure 2 is a schematic representation in block diagram form of a process for producing fibreglass.

Detailed Description

Figure 1 is a schematic representation in block diagram form of a process for producing a glass feedstock. Screen panels are separated 1 from CRTs and the glass comprising boron from the screen panels crushed 2. The crushed glass comprising boron from the CRT screen panels is mixed 3 with other glass 14, for example waste glass or new glass, to form a mixture. The mixture is screened 4 with the material passing through the screen forming a glass feedstock 5 and the material not passing through the screen being rejected 6. The rejected material may be returned for further processing. Additives 15, such as borax or boric oxide, may optionally be added 7 to the mixture before or after screening. As a consequence of using glass comprising boron, the amount of borax that has to be added may be reduced.

Figure 2 is a schematic representation in block diagram form of a process for producing fibreglass. Screen panels are separated 1 from CRT5 and the glass comprising boron from the screen panels crushed 2. The crushed glass comprising boron from the ORT screen panels is mixed 3 with other glass 14, for example waste glass or new glass, to form a mixture. The mixture is screened 4 with the material passing being fed to a furnace and formed 11 into fibreglass 12 and the material not passing through the screen being rejected 6. The rejected material may be returned for further processing. Additives 15, such as borax or boric oxide, may optionally be added 7 to the mixture before or after screening.

Whilst the above embodiment describes mixing 3 the glass comprising boron with the other glass 14 prior to feeding the glass into the furnace, it will be appreciated that in some embodiments the glass comprising boron may be fed into the furnace separately to the other glass, with the mixing then occurring in the furnace.

Whilst the present invention has been described and illustrated with reference to particular embodiments, it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different variations not specifically illustrated herein.

Where in the foregoing description, integers or

elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims. Moreover, it is to be understood that such optional integers or features, whilst of possible benefit in some embodiments of the invention, may not be desirable, and may therefore be absent, in other embodiments.

Claims

-10 -Claims 1. A process for producing a glass product, wherein the process comprises feeding glass comprising boron to a furnace and feeding other glass to the furnace.
2. A process according to claim 1, wherein the glass comprising boron is fed to the furnace separately to the other glass.
3. A process according to claim 1, wherein the glass comprising boron is mixed with the other glass prior to being fed to the furnace.
4. A process according to any preceding claim, wherein the glass comprising boron comprises at least 1% boron by mass.
5. A process according to any preceding claim, wherein the process includes the step of screening the glass feedstock at a screen size of not more than 6 mm.
6. A process according to any preceding claim, wherein the ratio of the glass comprising boron and the other glass fed to the furnace is from about 1:1 to about 1:20 by mass.
7. A process according to any preceding claim, wherein the glass comprising boron comprises glass from a cathode ray tube.
8. A process according to any preceding claim, wherein the glass product is fibreglass.
9. A process for producing a glass feedstock, wherein the process comprises mixing glass comprising boron with other glass.
10. A glass feedstock, wherein the feedstock includes a mixture of glass comprising boron and other glass.

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11 - 11. A glass feedstock according to claim 10, wherein the feedstock further includes an additive.
12. A glass feedstock according to claim 9, wherein the additive comprises boron.
13. A glass feedstock according to claim 11, wherein the additive comprises borax.
14. A glass feedstock according to claim 11, wherein the additive comprises boric oxide.
15. A glass feedstock according to any one of claims 10 to 13, wherein the glass feedstock has a boron content from about 4% to about 30% by mass.
16. A glass feedstock according to any one of claims to 15, wherein the glass feedstock comprises a multiplicity of glass particles, the particles having a a maximum dimension of no greater than about 6 mm.
17. A glass feedstock according to any one of claims to 16, wherein the mixture contains glass comprising boron and other glass in a ratio from about 1:1 to about 1:20 by mass.
18. A process of producing fibreglass, wherein the process comprises the step of mixing glass comprising boron with other glass.
19. A process for producing a glass product, substantially as herein described with reference to the accompanying drawings.
20. A process for producing a glass feedstock substantially as herein described with reference to the accompanying drawings.
21. A glass feedstock substantially as herein described with reference to the accompanying drawings.