Process and apparatus for enriching silicate in drinking water

Patent metadata

Field	Value
Publication number	US-11220448-B2
Application number	US-201916515833-A
Country	US
Kind code	B2
Filing date	Jul 18, 2019
Priority date	Jul 23, 2018
Publication date	Jan 11, 2022
Grant date	Jan 11, 2022

Abstract

Disclosed is a process for enriching silicate content in drinking water that includes separating raw water via reverse osmosis into a permeate comprising demineralised raw water and a retentate comprising mineral enriched raw water. The permeate is mixed with a water glass solution comprising sodium silicate and/or potassium silicate. An ion exchange process is used to reduce the concentration of sodium and/or potassium ions in at least part of the mixture. At least part of the retentate is supplied to the mixture after reducing the concentration of sodium and/or potassium ions to provide a silicate-enriched drinking water. Also disclosed is an apparatus for producing a drinking water enriched with silicate. The apparatus includes a reverse osmosis unit, a mixing unit, an ion exchanger, and a feed unit for feeding at least part of the retentate to the mixture after reducing the concentration of sodium and/or potassium ions.

First claim

What is claimed is:

1. A process for enriching silicate in drinking water, the process comprising:
separating raw water via a reverse osmosis process into a permeate comprising demineralised raw water and a retentate comprising mineral-enriched raw water;
mixing the permeate and a water glass solution to result in a mixture, the water glass solution comprising at least one of sodium silicate and potassium silicate;
subjecting at least a portion of the mixture to an ion exchange process to reduce a concentration of at least one of sodium ions and potassium ions, resulting in a mixture with a reduced concentration of sodium and/or potassium ions; and
supplying at least part of the retentate to the mixture with the reduced concentration of sodium and/or potassium ions, resulting in silicate-enriched drinking water.

2. The process of claim 1 , wherein the ion exchange process comprises at least one of reverse electrodialysis and electrodeionisation and uses only a bipolar membrane, only a cation membrane, or only a bipolar membrane and a cation membrane.

3. The process of claim 1 , wherein the silicate-enriched drinking water has a silicate concentration from 50 to 500 mg/l.

4. The process of claim 3 , wherein the silicate concentration is from 100 to 300 mg/l.

5. The process of claim 3 , wherein the silicate concentration is from 130 to 250 mg/l.

6. The process of claim 1 further comprising adding a food-safe hardness stabilizer to the raw water prior to separating the raw water via the reverse osmosis process.

7. The process of claim 6 , wherein the food-safe hardness stabilizer is CO 2 .

8. The process of claim 7 further comprising removing the CO 2 after the separating the raw water via the reverse osmosis process.

9. The process of claim 8 , wherein removing the CO 2 is performed after supplying to the mixture at least part of the retentate.

10. The process of claim 8 , wherein removing the CO 2 is carried out by vacuum degassing, pressure degassing or membrane degassing.

11. The process of claim 1 further comprising ultrafiltration (UF) to sterilize at least one of the raw water and the silicate-enriched drinking water.

Assignees

• Krones Ag

Inventors

• Scheu Dirk

Classifications

• B01D61/08

  Apparatus therefor · CPC title

• B01D61/465

  comprising the membrane sequence AB or BA, where B is a bipolar membrane · CPC title

• B01D61/422

  Electrodialysis · CPC title

• C02F1/441

  by reverse osmosis · CPC title

• C02F1/4693

  electrodialysis · CPC title