Enamels Glass-melting processes

Selenium. Compounds of Se are used for decolourising glass in the tank-melting process under other conditions this element will produce red coloured glass (see RUBY glass), pottery, or vitreous enamel. 

Aluminum fluoride is utilized, in addition to cryolite, as a raw material in the electrolytic manufacture of aluminum (temperature of electrolyte 950°C, composition 80-85% Na AlFft, 5-7% AIF, 5-7% CaF2, 2-6% AFO, 0-7% LiF). No fluorine should actually be consumed in this process, modern plants recovering the fluorine in its entirety. Other uses are as a flux (in welding, soldering, manufacture of casts), and as a melting point depressant in glass and enamel. The aluminum fluoride capacities in Europe are given in the table below. 

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