Conversion of plutonium scrap and residue to boroilicate glass using the GMODS process Page: 8 of 13
13 p.View a full description of this article.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
A typical experiment involved several hundred grams of material, with uranium and cerium being used
as plutonium surrogates. Plutonium tests have been proposed. The plutonium content of scrap and
residue is, at most, a few weight percent; hence, in terms of chemical processing, plutonium is a minor
component.
Addition offeed material to the molten dissolution glass (Fig. 1.b). The addition of feed materials
involves oxidation, dissolution, and mixing of feeds with the molten dissolution glass. Each of these
steps has been investigated.
Tests demonstrated the dissolution of U02, ZrO2, A1203, Ce203, MgO, and other oxides. The glasses
were examined by a variety of methods to ensure complete dissolution. As expected, the high-boron
oxide glass melt had good dissolution capabilities for oxides. In analytical chemistry, B203 is the
standard chemical reagent for fusion dissolution of unknown oxides because of its capability to dissolve
such materials. Boron oxide is also the key component in many welding fluxes, which are used to
dissolve iron oxides into a glassy slag during the welding process so that they are not incorporated into
the weld.
Oxidation-dissolution tests demonstrated the oxidation of the following metals and alloys followed by
the dissolution of their oxides into the melt: U, Ce, Zircaloy-2, Al, stainless steel, and other metals.
Figure 4 shows cerium glass and lead by-product from a test of oxidation of cerium metal (plutonium
surrogate).
Oxidation-dissolution tests also demonstrated the oxidation of carbon and graphite, with production of
CO2. For centuries, lead oxide has been used to oxidize organics10. It is the basis for the fire assay
method for recovering noble metals (primarily gold) from silicate rock. Lead oxide, various organics,
and silicate rocks are mixed together and heated. As the mixture melts, the lead oxide is reduced to
metal by the organic. The noble metals in the molten mass then dissolve into the lead, which forms a
separate layer that sinks to the bottom. This layer is then processed to separate the noble metal from
the lead.
Limited chloride dissolution tests with NaCl demonstrated that lead exits the dissolution glass as PbCl2
thus providing a separation of the chloride from other materials. This is a major mechanism for lead to
escape from processes where lead and chlorides coexist at high temperatures.1 The basic chemistry is
well understood.
Experimental measurements were made of the viscosity of the dissolution glass with various added
materials. Experience in the glass industry indicates that molten glass viscosities should be below 100
centipoise (about the viscosity of olive oil) for good mixing and creation of homogeneous glasses.
Based on our experimental data, the GMODS dissolution glass temperature will need to be between 800
and 1000* C. The final processing temperature after addition of the silica will be above 1000* C because
this addition increases glass viscosity.
Addition of glass additives [silicon oxide (SiO,) etc.] to improve the product quality (Fig. J.c). This
process step is essentially identical to that used for producing many specialty glasses."
Upcoming Pages
Here’s what’s next.
Search Inside
This article can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Article.
Forsberg, C. W.; Beahm, E. C.; Parker, G. W.; Rudolph, J.; Elam, K. R. & Ferrada, J. J. Conversion of plutonium scrap and residue to boroilicate glass using the GMODS process, article, November 28, 1995; Tennessee. (https://digital.library.unt.edu/ark:/67531/metadc673008/m1/8/: accessed July 16, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.