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AssigneeTRG Technologie Und Recyclingservice GmbH
InventorEberhard Giebeler
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The invention relates to a process for recovering amines from acid amine salt solutions by the addition of bases and evaporating the solution at a pH of 11 to 13 in a kneading drier until a useful solid is obtained as the distillation residue and a device for separating sludges and suspensions into a solid and a plurality of liquid fractions separated according to their boiling point. The low-water-content amine phase separated out by distillation is dehydrated with calcium oxide or potassium hydroxide and then separated into pure amine fractions by rectification. The process described makes it possible to utilise all the secondary flows and completely recycle the amines and the absorption medium (sulphuric acid). The flows for the recycling process are amine-charged washing acids from absorbers obtained from the cleaning of amine-containing exhaust gases, produced for instance in the cold box process for hardening core sand in foundries.
A process for recovering amines from acid amine scrub liquors comprising neutralizing an acid amine scrub mixture with a stoichiometric excess of a base, evaporating and distilling the liquid fraction of the resulting mixture in a kneading evaporator to obtain a solid distillation residue and a condensed amine/water phase and recovering amine from the amine/water phase.
A kneading evaporator provided with indirect heating and kneading gaps of 1.5 to 10 mm, the outlet being provided with a heat isolated dome, the dome being connected in series to a rectification column connected to a condenser.
Dependencies are inferred from the claim text.