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US 2016/0257574 A1Published application
Method of treating phosphate-containing ash from waste-incineration plants by wet-chemical digestion in order to obtain compounds of aluminium, calcium, phosphorus and nitrogen
AssigneeRemondis Aqua GmbH & Co. KG
InventorsJosef Lehmkuhl, Martin Lebek
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Abstract
The invention concerns a method of treating phosphate-containing waste, in particular phosphate-containing ash from waste-incineration plants, by wet-chemical digestion in order to obtain compounds of aluminium, calcium, phosphorus and nitrogen.
Claims20
A method for obtaining (generating) precipitates selected from the group of calcium nitrate (CaNO3), calcium phosphate (Ca3(PO4)2), calcium sulphate (CaSO4), and aluminium hydroxophosphate (Al(OH)3×AlPO4);
- from phosphate-containing ashes from waste incineration plants, the method comprising at least the obtaining (generation) of calcium phosphate (Ca3(PO4)2) and calcium nitrate (CaNO3), characterized in that
- a) the solids (ash) are reacted with nitric acid or phosphoric acid or a mineral acid mixture of these two acids,
- b) the acid-insoluble portion of the solids is separated,
- c) calcium phosphate precipitate and calcium nitrate precipitate is obtained and separated by addition of calcium oxide or calcium carbonate to the filtrate or supernatant.
1 more element
Dependencies are inferred from the claim text.