RU-2026108736-A - EXTRACTION OF PHOSPHORUS IN THE FORM OF ITS CHLORIDES FROM SEWAGE SLUDGE ASH

Inventors

• БОЛЛ, Маттиас

Assignees

• ЛЕНКСЕСС Дойчланд ГмбХ

Dates

Publication Date

20260507

Application Date

20240821

Priority Date

20230830

Claims (10)

1. 1. A method for extracting phosphorus in the form of its chlorides, in which wastewater sludge ash with a phosphorus content, expressed as wt.% of elemental phosphorus in the ash, of at least 2 wt.%, in the presence of a carbon source, is subjected to a reaction with elemental chlorine at a temperature of from 350 to 900°C, and the resulting phosphorus chlorides are separated from the exhaust gas stream.
2. 2. The method according to claim 1, characterized in that the sewage sludge ash used has a phosphorus content, expressed as a mass percentage of elemental phosphorus in the ash, of at least 3%, preferably from 3 to 29 mass%.
3. 3. The method according to claim 1, characterized in that the wastewater sludge ash used has an iron content of 5 to 21% by weight, calculated as elemental iron.
4. 4. The method according to paragraph 1, characterized in that the reaction with elemental chlorine is carried out at a temperature from 450 to 850°C.
5. 5. The method according to claim 1, characterized in that the wastewater sludge ash used contains iron, and the resulting iron chloride together with the resulting phosphorus chlorides are removed in the exhaust gas stream, and the iron chloride and phosphorus chlorides are separated from the exhaust gas stream.
6. 6. The method according to claim 1, characterized in that the phosphorus chlorides formed from the exhaust gas stream, in particular phosphorus oxychloride and optionally phosphorus trichloride and/or phosphorus pentachloride, are precipitated by condensation.
7. 7. The method according to claim 1, characterized in that the carbon source is selected from the group of graphite, soot, coal, coke, activated carbon, carbon monoxide, oils, methane, polyethylene glycol, biowaste and, in particular, sewage sludge.
8. 8. The method according to claim 1, characterized in that the ratio of the mass fractions of carbon of the carbon source to the ash of the sewage sludge is more than 0.01, preferably from 0.04 to 0.5.
9. 9. The method according to claim 1, characterized in that if the proportion of carbon in the carbon source is less than 70 wt.%, then the mixture of sewage sludge ash and the carbon source is treated in an inert gas at temperatures from 250 to 800°C, preferably from 350 to 550°C, before reacting with gaseous chlorine, until the gas formation of volatile components is less than 1 l/1 kg of the carbon source used/hour.
10. 10. The method according to one of paragraphs 1-9, characterized in that the remainder of the insoluble components is separated with water.