Process for thermal decomposition of aluminum chloride hydrates by indirect heat
AssigneeAluminum Pechiney
InventorsLothar Reh, Ludolf Plass, Philippe Marchessaux
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Abstract
Thermal decomposition of aluminum chloride hydrate in a fluidized bed reactor in which the concentration of solids diminishes from the bottom upwards, the improvement wherein most of the hydrogen chloride is removed from the hydrate by direct heat and the largely decomposed aluminum chloride is fed into a calcining reactor and from the calcining reactor to a residence time reactor fluidized at low gas velocity, recycling solids from the residence reactor to the calcining reactor in an amount to adjust the suspension density and feeding the remainder to a cooler after sufficient time in the residence reactor.
Claims20
A continuous process for the thermal decomposition of aluminum chloride hydrate into solid aluminum oxide and gaseous hydrogen chloride comprising
- (1) introducing the aluminum chloride hydrate into a decomposition reaction zone,
- (2) introducing a fluidizing gas into the decompositon reaction zone to maintain the aluminum chloride hydrate in a fluidized state within said reaction zone,
- (3) indirectly heating the aluminum chloride hydrate, while in the fluidized state in said reaction zone until a preponderant portion of the thermal decomposition of the aluminum chloride hydrate has taken place in said reaction zone,
- (4) separating the effluent from the reaction zone into a gaseous phase containing hydrogen chloride and a solid phase of partially decomposed aluminum chloride hydrate,
- (5) passing the separated solid phase of partially decomposed aluminum chloride hydrate to a directly heated calcining zone,
- (6) calcining the partially decomposed aluminum chloride hydrate in the calcining zone to advance the thermal decomposition of the partially decomposed aluminum chloride hydrate,
- (7) passing the calcined aluminum chloride hydrate from the calcining zone into a residence reaction zone,
- (8) introducing gases into the residence reaction zone in an amount to maintain the solid material in a fluidized state,
- (9) recycling a portion of the solid material from the residence reaction zone to the calcining zone, and
- (10) cooling a portion of the solid material zone, and
- (10) cooling a portion of the solid material from the residence reaction zone as product.
Dependencies are inferred from the claim text.