RU-2026108735-A - Extraction of silicon tetrachloride from biochar

Inventors

• БОЛЛ, Маттиас

Assignees

• ЛЕНКСЕСС Дойчланд ГмбХ

Dates

Publication Date

20260508

Application Date

20240823

Priority Date

20230830

Claims (11)

1. 1. A method for extracting silicon in the form of tetrachloride, in which biochar with a silicon content, expressed as wt.% elemental silicon, of at least 1 wt.% is reacted with elemental chlorine at a temperature of 350 to 900°C, and the resulting silicon tetrachloride is separated from the exhaust gas stream, preferably by condensation.
2. 2. The method according to claim 1, characterized in that the biochar has a silicon content, expressed in wt.% of elemental silicon, of at least 5 wt.%, preferably from 5 to 40 wt.%, particularly preferably from 7 to 30 wt.%.
3. 3. The method according to claim 1, characterized in that the interaction with elemental chlorine is carried out at a temperature from 400 to 850°C, particularly preferably from 500°C to 800°C.
4. 4. The method according to claim 1, characterized in that the biochar has a phosphorus content, expressed in wt.% of elemental phosphorus, of at least 2 to 19 wt.%, in particular 5 to 16 wt.%.
5. 5. The method according to claim 1, characterized in that the biochar has an iron content of 3 to 14 wt.% and aluminum of 0.4 to 13 wt.%, each expressed in wt.% in the form of elements.
6. 6. The method according to claim 1, characterized in that the biochar is a residue from the pyrolysis of biomass, in particular sewage sludge, preferably with a water content of less than 15 wt.%, in particular less than 12 wt.%, preferably <8 wt.%, particularly preferably from 0.5 to 7 wt.%, which is obtained by heating the biomass in an oxygen-depleted atmosphere at temperatures from 250 to 800°C.
7. 7. The method according to claim 4 for extracting phosphorus chlorides, in which the formed phosphorus and silicon chlorides are separated from the exhaust gas stream.
8. 8. The method according to claim 1, characterized in that the resulting phosphorus chlorides, in particular phosphorus oxychloride and phosphorus trichloride, and/or phosphorus pentachloride, and/or silicon tetrachloride, are separated from the exhaust gas stream by condensation.
9. 9. The method according to one of paragraphs 1-8, characterized in that the chlorination residue is separated from the insoluble components using water.
10. 10. A method for producing SiCl 4 , characterized in that bioash in the presence of a carbon source is subjected to interaction with elemental chlorine at a temperature of 350 to 900°C and the resulting SiCl 4 is separated from the exhaust gas stream.
11. 11. Use of biochar and/or bioash, in particular sewage sludge ash, to produce SiCl 4 by chlorination in the presence of a carbon source.