High shear mixer and glass melting method

• US 5,364,426 A
• Filed: 09/16/1993
• Issued: 11/15/1994
• Est. Priority Date: 03/07/1991
• Status: Expired due to Term

• Current Assignee: Stir-Melter Incorporated
• Original Assignee: Stir-Melter Incorporated
• Inventors: Richards, Ray S.
• Primary Examiner(s): LINDSAY JR, ROBERT
• Application Number:
  US08/122,914
• Time in Patent Office: 425 Days
• Field of Search: 65/2, 65/27, 65/28, 65/134-136, 65/178
• US Class Current: 65/474
• CPC Class Codes: B09B 3/0066 Disposal of asbestos
• CPC Class Codes: C03B 3/00 Charging the melting furnaces
• CPC Class Codes: C03B 5/005 of glass-forming waste materials disposal or transformation of solid waste in general B09B; treatment of radioactive waste G21F9/00
• CPC Class Codes: C03B 5/027 by passing an electric current between electrodes immersed in the glass bath, i.e. by direct resistance heating
• CPC Class Codes: C03B 5/187 with moving elements
• CPC Class Codes: C03B 5/1875 of the screw or pump-action type
• CPC Class Codes: C03B 5/193 using gas, e.g. bubblers
• CPC Class Codes: C03B 5/225 Refining C03B5/18 takes precedence ; Refining agents C03C1/004
• CPC Class Codes: C03B 5/2252 under reduced pressure, e.g. with vacuum refiners
• CPC Class Codes: Y02P 40/50 Glass production, e.g. reusing waste heat during processing or shaping
• CPC Class Codes: Y10S 65/04 Electric heat

Abstract

A glass melter 30 having a mixing impeller 34 for converting a feed stream 38 supplied to a vessel 32 into a vitrified glass melt 50. Heating means such as electrodes 36 or a gas burner 58 are used to heat the glass melt 50. Electrode 36 arrangements are proposed for minimizing current flow through the impeller 34. Current flow through a special continuous circular impeller or conical pump 70 is disclosed. A cylindrical vessel 98, triangular vessel 94, square vessel 32, and hexagonal vessel 96 are disclosed. Methods of processing particular waste streams are disclosed including coated mineral fibers, fly ash, radioactive material, chemical waste and the like.

Claims

1. A method of recycling coated mineral fibers having an organic coating comprising the steps of:

depositing coated mineral fibers into a vessel containing a molten glass bath;

stirring the molten glass bath at a speed sufficient to create a surface currents which convey the coated mineral fibers along with the surface currents;

heating the coated mineral fibers while being conveyed by the surface currents to decompose said organic coating on the mineral fibers leaving a residue and mineral fibers, said residue comprising carbon;

oxidizing a first portion of said residue as said mineral fibers are conveyed by said surface currents across a portion of the surface of said molten glass bath;

dispersing the mineral fibers and a second portion of the residue into the molten glass bath with a stirrer rotating at a speed sufficient to make a mineral fiber and residue dispersion in the molten glass bath; and

heating the mineral fiber and residue dispersion to melt the mineral fibers with said second portion of said residue to create a carbon/glass melt as carbon from said second portion of residue is released into said molten glass bath.

2. The method of claim 1 further comprising the step of oxidizing said carbon in carbon/glass melt by combining the carbon in said carbon/glass melt with an oxidizer to form carbon oxides.

3. The method of claim 2 wherein said oxidizing step comprises the following reaction:

space="preserve" listing-type="equation">C+O.sub.2 →

CO.sub.x

4. The method of claim 2 wherein said oxidizing step comprises the following reaction:

space="preserve" listing-type="equation">Na.sub.2 O+C→

CO.sub.x +Na

5. The method of claim 2 wherein said oxidizing step comprises the following reaction:

space="preserve" listing-type="equation">C+SiO.sub.2 →

CO+SiO

6. The method of claim 2 wherein said oxidizing step comprises the following reaction:

space="preserve" listing-type="equation">C+H.sub.2 O→

CO+H.sub.2

7. The method of claim 2 wherein said oxidizing step is carried out in a second stage remote from said vessel in which said depositing, stirring and heating steps are performed.

8. The method of claim 7 wherein said oxidizing step further comprises pouring said portion of said carbon containing molten glass bath into a rotating disc which distributes said portion of said contaminated glass bath above and about said second stage wherein carbon is oxidized by an oxidizer in the region above said second stage.

9. The method of claim 7 wherein said oxidizing step further comprises pouring said portion of said carbon containing molten glass bath into a rotating cone-shaped member which distributes said portion of said contaminated glass bath above and about said second stage wherein carbon is oxidized by an oxidizer in the region above said second stage.

10. The method of claim 2 wherein said oxidizing step further comprises supplying an oxidizer into the molten glass bath to oxidize said carbon.

11. The method of claim 2 wherein said oxidizing step further comprises heating said molten glass bath to a temperature greater than 2,500°

F. at which point carbon reacts with sodium compounds in said molten glass bath to form gases.

12. The method of claim 2 wherein said oxidizing step further comprises heating said molten glass bath to a temperature greater than 2,650°

F. at which point carbon reacts with silicon compounds in said molten glass bath which combines with said carbon contaminates.

13. The method of claim 1 further comprising the step of supplying the portion of said molten glass bath to a mineral glass fiber forming operation after removal of substantially all of said carbon contaminates therefrom whereby said mineral fibers are recycled into mineral glass fibers.