Decolorizing of glass

Period of Wide Technical Application. In the time between 1930 and 1940 work was done on various applications for the rare earth elements. Particularly successful was the production of sunglasses ("Neophan"), polishing media from rare earth oxides to replace iron oxide, decolorization of glass using cerium oxide, pure cerivim oxide as opacifier in ceramic glazes, use of cerium... 

Schutt, T. C. Barlow, G. "Practical Aspects of Cerium Decolorization of Glass" Amer. Ceram. Soc. Bull., 1972, 51, ... 

Decolorization of glass by fluorine-containing substances is attributed to the formation of iron-fluoiine complexes, perhaps FeFg. 

As ceric sulfate is used extensively as a volumetric oxidizing agent in quantitative analysis. Cerium compounds are used in the manufacture of glass, both as a component and as a decolorizer. 

In the glass (qv) and ceramic industry (see Ceramics), barite can be used both as a flux, to promote melting at a lower temperature or to increase the production rate, and as an additive to increase the refractive index of glass. The viscosity of barite-containing glass often needs to be raised. Alumina in the form of feldspar is sometimes used. To offset any color produced by iron from the barite addition, more decolorizer may be needed. When properly used, barytes help reduce seed, increase toughness and brilliancy, and reduce annealing time. Barite is also a raw material for the manufacture of other barium chemicals. 

Anaerobic decolorization of azo dyes was started back in the 1970s. Reticulated sintered glass was used as immobilization of anaerobic bacteria for the decolorization of wastewater and transformation of the azo dye to degradable products [58], Full decolorization was achieved in less than 4 h HRT, and in addition to it, methane as biogas was also produced. 

Current uses of arsenic are in pesticides, cotton desiccants, and wood preservatives. Arsenic is also used as a bronzing and decolorizing agent in the manufacture of glass, and in the production of semiconductors (Tanaka, 2004), as a desiccant and defoliant in agriculture, and as a byproduct of the smelting of nonferrous metals, particularly gold and copper, from coal residues (Hall, 2002). 

Table 5. Decoloration of photochrome VIII copolymers. Influence of the glass transition tempera-...

The most important compound of Mn, Mn02 or manganese dioxide, is a brown-black solid used as a decolorizer in glass, to prepare other Mn compounds, and in dry cells. 

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