Aluminium sulfate, decomposition

When the poisoned catalysts are subjected to heat (c.g 773 K) in air, MS will change into S(VI) or S(IV) (or S02)t but the original S(VI) in the catalysts is essentially unchanged (Fig.4) As the temperature rises to ca 973 K, the decomposition of aluminium sulfate hydrate will lake place. When poisoned catalysts undergo a temperature programmed... 

Govindarajan, S. and Patil, K.C. (1982) Thermal decomposition of hydrazinium aluminium sulfate hydrate and hydrazinate. Thermochimica Acta, 55, 373-376. 

Gibson s method 4 is based on the principle that ammonium hydrogen fluoride effects the complete decomposition of beryl at a low temperature, even if the mineral is only coarsely ground. Much of the silica is volatilized as ammonium fluosilicate and the beryllium and aluminium converted first to fluorides, then sulfates. The former is separated by solution in (NH COs. 

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