Back to results
US 10,329,153 B2Granted
Method for purifying raw phosphoric acid (e.g. MGA acid) by adding ashes originating from waste incineration plants, comprising the production of pure phosphoric acid, calcium sulfate, water-soluble calcium hydrogen phosphates and metal salt solution
AssigneeRemondis Aqua GmbH & Co. KG
InventorsJosef Lehmkuhl, Martin Lebek
Life of this patent
Estimating the term…
Abstract
The present invention relates to a method for purifying raw phosphoric acid by adding ashes originating from waste incineration plants, as well as calcium hydroxide and at least one sulfide, and by wet-chemical digestion for obtaining (producing) calcium sulfate, pure phosphoric acid, metal salt solution and/or calcium hydrogen phosphates (e.g. triple superphosphate).
Claims19
A method for purifying raw phosphoric acid comprising
- a) reacting raw phosphoric acid with ash that is obtained by incinerating phosphate containing sewage sludges, biodegradable wastes, bio-wastes and/or animal wastes in a waste incineration plant, calcium hydroxide and at least one sulfide,
- b) separating the acid-insoluble portion of the solids formed in step a), so that a filtrate or eluate is obtained ,
- b2) recovering a filtrate or eluate, comprising phosphoric acid after step b),
- c) adding sulfuric acid to the filtrate or eluate of step b2) to adjust the pH to a value of <1 and to obtain and separate calcium sulfate precipitate;
- and
- d) recycling at least part of the filtrate or eluate after step c) for use in step a).
3 more elements
Dependencies are inferred from the claim text.