Title: Method of treating by silicopyrohydrolysis worn linings from hall-heroult electrolysis tanks
Application Number: 88103256 Application Date: 1988.05.31
Publication Number: 1022763 Publication Date: 1988.12.14
Approval Pub. Date: 1992.04.08 Granted Pub. Date: 1992.04.08
International Classifi-cation: B09B3/00;C25C3/06
Applicant(s) Name: Aluminium Pechiney Address:
Inventor(s) Name: Michel Leroy
Attorney & Agent: WU DAJIAN
Abstract:
    A process for treating worn linings by silicopyrohydrolysis, the linings originating especially from Hall-Heroult electrolysis cells and consisting of a mixture of carbon-containing products and silico- aluminous products impregnated with fluorine-containing inorganic compounds especially of sodium, calcium and aluminium, consisting in converting these linings by treatment at a temperature of at least 1000 DEG C by means of an oxidising gas, water vapour and silica, - firstly in a gas phase containing most of the fluorine, in the form of hydrofluoric acid, and of the carbon, in the form of carbon dioxide and monoxide, - secondly, in an at least partially liquid phase containing the silicon, the aluminium, the calcium and the sodium and most of the other impurities (iron, titanium, heavy metals etc.) in the form of oxygen-containing compounds, essentially in the form of silicates. The process can be used in a single stage or in two stages in two successive reactors.
Time: 8
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