Micronized CaCO3 slurry injection system for the remineralization of desalinated and fresh water

Patent metadata

Field	Value
Publication number	US-9598295-B2
Application number	US-201214129313-A
Country	US
Kind code	B2
Filing date	Jul 17, 2012
Priority date	Jul 22, 2011
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

The present invention concerns a process for treating water and the use of calcium carbonate in such a process. In particular, the present invention is directed to a process for remineralization of water comprising the steps of (a) providing feed water having a concentration of carbon dioxide of at least 20 mg/l, preferably in a range of 25 to 100 mg/l, and more preferably in a range of 30 to 60 mg/l, (b) providing an aqueous slurry comprising micronized calcium carbonate, and (c) combining the feed water of step (a) and the aqueous slurry of step (b) in order to obtain remineralized water.

First claim

The invention claimed is:

1. A process for remineralization of feed water comprising the steps of:
a) providing feed water in need of remineralization, wherein the feed water has a concentration of free carbon dioxide of 20 to 60 mg/l that is not a result of addition of gaseous carbon dioxide to the feed water,
b) providing an aqueous slurry comprising 2 to 40 wt.-% of micronized calcium carbonate based on the total weight of the slurry, wherein the micronized calcium carbonate has a particle size from 0.5 to 15 μm, and a HCl insoluble content from 0.02 to 2.5 wt.-% based on the total weight of the micronized calcium carbonate, and
c) combining the feed water of step a) and the aqueous slurry of step b) in order to obtain remineralized water.

2. The process according to claim 1 , wherein the feed water has a concentration of carbon dioxide of 30 to 60 mg/l.

3. The process of claim 1 , wherein the concentration of calcium carbonate in the slurry is from 2 to 25 wt.-%, based on the total weight of the slurry.

4. The process of claim 1 , wherein the concentration of calcium carbonate in the slurry is from 2 to 20 wt.-%, based on the total weight of the slurry.

5. The process of claim 1 , wherein the concentration of calcium carbonate in the slurry is from 3 to 15 wt.-%, based on the total weight of the slurry.

6. The process of claim 1 , wherein the calcium carbonate has a particle size from 2 to 10 μm.

7. The process of claim 1 , wherein the calcium carbonate has a particle size from 3 to 5 μm.

8. The process of claim 1 , wherein the calcium carbonate has a HCl insoluble content from 0.05 to 1.5 wt.-%, based on the total weight of the micronized calcium carbonate.

9. The process of claim 1 , wherein the calcium carbonate has a HCl insoluble content from 0.1 to 0.6 wt.-%, based on the total weight of the micronized calcium carbonate.

10. The process of claim 1 , wherein the calcium carbonate is a ground calcium carbonate, modified calcium carbonate, or precipitated calcium carbonate, or any mixture thereof.

11. The process of claim 1 , wherein the slurry comprises further minerals containing magnesium, potassium, sodium, magnesium carbonate, calcium magnesium carbonate, dolomitic limestone, calcareous dolomite, dolomite, half-burnt dolomite, magnesium oxide, burnt dolomite, magnesium sulfate, potassium hydrogen carbonate, or sodium hydrogen carbonate.

12. The process of claim 1 , wherein the time period between the preparation of the slurry in step b) and combining the slurry with the feed water in step c is less than 24 hours.

13. The process of claim 1 , wherein the time period between the preparation of the slurry in step b) and combining the slurry with the feed water in step c is less than 2 hours.

14. The process of claim 1 , wherein the obtained remineralized water has a calcium concentration as calcium carbonate from 15 to 200 mg/l.

15. The process of claim 1 , wherein the obtained remineralized water has a calcium concentration as calcium carbonate from 50 to 150 mg/l.

16. The process of claim 1 , wherein the obtained remineralized water has a calcium concentration as calcium carbonate from 100 to 125 mg/l.

17. The process of claim 1 , wherein the obtained remineralized water has a calcium concentration as calcium carbonate from 15 to 100 mg/l.

18. The process of claim 1 , wherein the obtained remineralized water has a calcium concentration as calcium carbonate from 20 to 80 mg/l.

19. The process of claim 1 , wherein the obtained remineralized water has a calcium concentration as calcium carbonate from 40 to 60 mg/l.

20. The process of claim 1 , wherein the slurry comprises further minerals containing magnesium and the obtained remineralized water has a magnesium concentration from 5 to 25 mg/l.

21. The process of claim 1 , wherein the remineralized water has a turbidity value of lower than 5.0 NTU.

22. The process of claim 1 , wherein the remineralized water has a turbidity value of lower than 1.0 NTU.

23. The process of claim 1 , wherein the remineralized water has a turbidity value of lower than 0.5 NTU.

24. The process of claim 1 , wherein the remineralized water has a turbidity value of lower than 0.3 NTU.

25. The process of claim 1 , wherein the remineralized water has one or more of a Langlier Saturation Index from −2 to 1, a Slit Density Index SDI 15 below 5, and a Membrane Fouling Index MFI 0.45 below 4.

26. The process of claim 1 , wherein the remineralized water has one or more of a Langlier Saturation Index from −1.9 to 0.9, a Slit Density Index SDI 15 below 4, and a Membrane Fouling Index MFI 0.45 below 2.5.

27. The process of claim 1 , wherein the remineralized water has one or more of a Langlier Saturation Index from −0.9 to 0, a Slit Density Index SDI 15 below 3, and a Membrane Fouling Index MFI 0.45 below 2.

28. The process of claim 1 , wherein the feed water is desalinated seawater, brackish water, brine, treated wastewater, natural water, ground water, surface water or rainfall.

29. The process according to claim 1 , wherein the remineralized water is blended with feed water.

30. The process according to claim 1 , wherein the process further comprises a particle removal step.

31. The process according to claim 1 , wherein one or more of a alkalinity, conductivity, calcium concentration, pH, total dissolved solids and turbidity is measured and compared to a predetermined parameter value, and the amount of slurry is adjusted based on the difference between the measured and the predetermined parameter value.

32. The process of claim 31 , wherein the predetermined parameter value is a pH value, wherein the pH value is from 5.5 to 9.

33. The process of claim 31 , wherein the predetermined parameter value is a pH value, wherein the pH value is from 7 to 8.5.

Assignees

• Skovby Michael
• Poffet Martine
• Omya Int Ag

Inventors

• Skovby Michael
• Poffet Martine

Classifications

• C02F2209/055

  Hardness · CPC title

• C02F2209/003

  Downstream control, i.e. outlet monitoring, e.g. to check the treating agents, such as halogens or ozone, leaving the process · CPC title

• C02F2301/043

  Treatment of partial or bypass streams · CPC title

• C02F1/001

  Processes for the treatment of water whereby the filtration technique is of importance (C02F1/44 takes precedence; construction of filters in general B01D24/00 - B01D41/00) · CPC title

• C02F2103/08

  Seawater, e.g. for desalination · CPC title