Low melting high lithia glass compositions and methods

• US 6,630,419 B2
• Filed: 03/28/2002
• Issued: 10/07/2003
• Est. Priority Date: 05/02/1998
• Status: Expired due to Fees

• Current Assignee: Savannah River Nuclear Solutions LLS
• Original Assignee: Westinghouse Savannah River Company
• Inventors: Jantzen, Carol M., Marra, James C., Cicero-Herman, Connie A., Pickett, John B.
• Primary Examiner(s): SAMPLE, DAVID R
• Application Number:
  US10/108,847
• Publication Number:
  US 20020177516A1
• Time in Patent Office: 558 Days
• Field of Search: 501/69, 501/70, 501/72, 588/11, 588/14, 588/15, 588/901
• US Class Current: 501/69
• CPC Class Codes: C03C 1/002 Use of waste materials, e.g. slags
• CPC Class Codes: C03C 3/064 containing boron
• CPC Class Codes: C03C 3/087 containing calcium oxide, e.g. common sheet or container glass
• CPC Class Codes: C03C 3/091 containing aluminium
• CPC Class Codes: C03C 3/105 containing aluminium
• CPC Class Codes: Y10S 588/901 Compositions

Abstract

The invention relates to methods of vitrifying waste and for lowering the melting point of glass forming systems by including lithia formers in the glass forming composition in significant amounts, typically from about 0.16 wt % to about 11 wt %, based on the total glass forming oxides. The lithia is typically included as a replacement for alkali oxide glass formers that would normally be present in a particular glass forming system. Replacement can occur on a mole percent or weight percent basis, and typically results in a composition wherein lithia forms about 10 wt % to about 100 wt % of the alkali oxide glass formers present in the composition. The present invention also relates to the high lithia glass compositions formed by these methods. The invention is useful for stabilization of numerous types of waste materials, including aqueous waste streams, sludge solids, mixtures of aqueous supernate and sludge solids, combinations of spent filter aids from waste water treatment and waste sludges, supernate alone, incinerator ash, incinerator offgas blowdown, or combinations thereof, geological mine tailings and sludges, asbestos, inorganic filter media, cement waste forms in need of remediation, spent or partially spent ion exchange resins or zeolites, contaminated soils, lead paint, etc. The decrease in melting point achieved by the present invention desirably prevents volatilization of hazardous or radioactive species during vitrification.

Claims

1. An alkali oxide-magnesia-silica glass composition suitable for immobilizing radioactive, hazardous, or mixed waste, comprising:

(a) SiO₂ in an amount ranging from about 40 wt % to about 68 wt %;

(b) MgO in an amount ranging from about 5.0 wt % to about 15 wt %;

(c) Na₂O in an amount ranging from about 7.0 wt % to about 20 wt %;

(d) Li₂O in an amount ranging from about 3.0 wt % to about 9.0 wt %;

(e) a waste loading, said waste loading being up to about 70% by wt; and

(f) said loaded glass composition being opaque.

2. The alkali oxide-magnesia-silica glass composition according to claim 1, further comprising:

(e) K₂O in an amount ranging from about 0.05 wt % to about 0.2 wt %.

3. The alkali oxide-magnesia-silica glass composition according to claim 1, further comprising:

(f) Fe₂O₃ in an amount ranging from about 8.0 wt % to about 22 wt %.

4. The alkali oxide-magnesia-silica glass composition according to claim 1, further comprising:

(g) Al₂O₃ in an amount ranging from about 0.1 wt % to about 0.7 wt %.

5. The alkali oxide-magnesia-silica glass composition according to claim 1, further comprising:

(h) CaO in an amount ranging from about 0.15 wt % to about 0.75 wt %.

6. The glass composition of claim 1 where the waste loading is asbestos containing material.

7. The glass composition of claim 1 wherein the melting point of said glass is about 1150°

C.