Inorganic based strippable coatings for isolating hazardous materials and method for making and using the same

• US 5,205,864 A
• Filed: 12/20/1991
• Issued: 04/27/1993
• Est. Priority Date: 12/20/1991
• Status: Expired due to Fees

• Current Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Original Assignee: Westinghouse Electric Corporation (Paramount Global (f/k/a ViacomCBS Inc.))
• Inventors: Snyder, Thomas S.
• Primary Examiner(s): BRUNSMAN, DAVID M
• Application Number:
  US07/811,362
• Time in Patent Office: 494 Days
• Field of Search: 106/287.16, 106/287.26, 501/12, 501/155, 134/1, 134/4, 427/397.7
• US Class Current: 106/287.26
• CPC Class Codes: C09D 5/20 for coatings strippable as coherent films, e.g. temporary coatings strippable as coherent films
• CPC Class Codes: C09K 3/22 for dust-laying or dust-absorbing
• CPC Class Codes: G21F 9/001 Decontamination of contaminated objects, apparatus, clothes, food; Preventing contamination thereof

Abstract

An inorganic based strippable coating is provided for isolating hazardous materials. The coating is formed from a metal alkoxide material which undergoes a sol-gel reaction to form a metal oxide material. While the sol is still in a green state, the sol is applied to the surface to be protected. Any hazardous material such as nuclear contamination present on the surface is trapped within the matrix of the sol. The sol coating may be stripped from the surface while in a green state or may be allowed to harden. Once hardened, the sol forms a metal oxide coating which will deter the future accumulation of contamination.

Claims

1. A process for isolating contamination on a surface of a vessel comprising the steps of

(a) forming a metal alkoxide sol-gel solution;

(b) applying said sol-gel solution to said vessel surface;

(c) allowing said solution to dry, said contamination being fixed in the matrix of said coating;

(d) removing at least a portion of said coating from said vessel; and

(e) firing said removed coating to form a silica-encapsulated waste.

2. The process of claim 1 wherein the metal alkoxide is a silica-based compound.

3. The process of claim 2 wherein said metal alkoxide is formed by reacting silicon chloride with at least one of methanol and ethanol under anhydrous conditions.

4. The process of claim 1 wherein said metal alkoxide sol-gel solution is mixed with ethanol prior to applying to said surface of said vessel.

5. The method of claim 1 wherein said coating is removed from said vessel by at least one of cutting, scraping, hydrolasering and scabbling.

6. The process of claim 1 further comprising the steps of chopping and shredding said removed coating before forming said silica-encapsulated waste.

7. The process of claim 1 wherein a film of said coating resides on said vessel after removing said at least a portion of said coating, said residual film forming a solid silica coating when cured.