Process to preserve aqueous preparations of mineral materials, preserved aqueous preparations of mineral materials and use of preservative compounds in aqueous preparations of mineral materials

1. An aqueous preparation obtained by a process for preserving an aqueous preparation of mineral material, wherein the process comprises the steps of:

(a) providing an aqueous preparation of mineral material at a solids content of 10 to 85% by dry weight relative to the total weight of the aqueous preparation, wherein the mineral material consists of ground calcium carbonate, precipitated calcium carbonate, dolomite, ground calcium carbonate surface treated with a fatty acid, precipitated calcium carbonate surface treated with a fatty acid, surface reacted ground calcium carbonate, surface-reacted precipitated calcium carbonate, or any mixture thereof;

(b) adding to the aqueous preparation of step (a) one or more sources of lithium ions in an amount such that the total amount of lithium ions in the aqueous preparation is from 750 to less than 3000 ppm, calculated relative to the water in the preparation; and

(c) adding to the aqueous preparation of step (a) one or more sources of sodium ions and/or potassium ions in an amount such that the total amount of sodium ions and/or potassium ions in the aqueous preparation is from 3000 to less than 7500 ppm, calculated relative to the water in the preparation,

where steps (b) and (c) may be carried out simultaneously, or separately in any order, in order to preserve the aqueous preparation of the mineral material so that the aqueous preparation so preserved has a bacterial count of less than 10 4 cfu/ml.

2. The aqueous preparation according to claim 1 , having a solids content of 20 to 80% by dry weight relative to the total weight of the aqueous preparation.

3. The aqueous preparation according to claim 1 , wherein the aqueous preparation of step a) has a pH value of 6 to 10.5.

4. The aqueous preparation according to claim 1 , wherein the aqueous preparation of step a) has a pH value of 7 to 10.

5. The aqueous preparation according to claim 1 , wherein the aqueous preparation of step a) has a viscosity of from 50 to 800 mPa·s.

6. The aqueous preparation according to claim 1 , wherein the aqueous preparation of step a) has a viscosity of from 80 to 600 mPa·s.

7. The aqueous preparation according to claim 1 , wherein the mineral material consists of ground calcium carbonate obtained from marble, limestone and/or chalk.

8. The aqueous preparation according to claim 1 , wherein the mineral material consists of precipitated calcium carbonate.

9. The aqueous preparation according to claim 1 , wherein the source of the lithium ions is a water soluble lithium compound, a lithium salt, lithium carbonate, a polymeric salt of lithium, a mixture of lithium carbonate with a polymeric salt of lithium, or a lithium salt of an acrylic homopolymer, an acrylic copolymer, a copolymer of acrylic acid and maleic acid and/or acrylamide, a polyphosphate, or any mixture thereof.

10. The aqueous preparation according to claim 1 , wherein the source of the lithium ions is a polymeric salt of lithium selected from Li 2 Na 2 polyphosphate, lithium-sodium hexamethaphosphate, and lithium polyacrylate.

11. The aqueous preparation according to claim 1 , wherein the source of the lithium ions is lithium carbonate.

12. The aqueous preparation according to claim 1 , wherein the source of the lithium ions is lithium carbonate and a polymeric salt of lithium at a weight ratio of lithium carbonate:polymeric salt of lithium from 50:50 to 99.9:0.1.

13. The aqueous preparation according to claim 1 , wherein the lithium ions are provided to the aqueous preparation of step a) in an amount such that the total amount of lithium ions in the aqueous preparation is from 750 to 1500 ppm, calculated relative to the water in the preparation.

14. The aqueous preparation according to claim 1 , wherein the source of the sodium ions and/or potassium ions is selected from the group consisting of a water soluble sodium compound, a water soluble potassium compound, sodium carbonate, potassium carbonate, sodium chloride, potassium chloride, and any mixture thereof, a mixture of one or more of sodium chloride and potassium chloride with a polymeric salt of one or more of sodium and potassium, and a mixture of one or more of sodium carbonate and potassium carbonate with a polymeric salt of one or more of sodium and potassium.

15. The aqueous preparation according to claim 1 , wherein the source of the sodium ions and/or potassium ions is one or more of sodium carbonate and potassium carbonate.

16. The aqueous preparation according to claim 1 , wherein the source of the sodium ions and/or potassium ions is sodium carbonate.

17. The aqueous preparation according to claim 1 , wherein the source of sodium ions and/or potassium ions is provided to the aqueous preparation of step (a) in an amount such that the total amount of sodium ions in the aqueous preparation is from 5000 to 7000 ppm, calculated relative to the water in the preparation.

18. The aqueous preparation according to claim 1 , wherein the source of the lithium ions of step (b) and the source of the sodium ions and/or potassium ions of step (c) are added simultaneously to the aqueous preparation of step (a).

19. The aqueous preparation according to claim 1 , wherein the source of lithium ions of step (b) and source of sodium ions and/or potassium ions of step (c) are added separately to the aqueous preparation of step (a).

20. The aqueous preparation according to claim 1 , wherein when the source of lithium ions is a polymeric salt, the polymeric salt of lithium is added prior to the source of sodium ions and/or potassium ions.

21. The aqueous preparation according to claim 1 , wherein when the source of sodium ions and/or potassium ions is a polymeric salt, the polymeric salt of one or more of sodium and potassium is added prior to the source of lithium ions.

22. The aqueous preparation according to claim 1 , wherein no biocide other than the biocide formed by addition of lithium ions and sodium ions and/or potassium ions is added.

23. A preparation comprising a dried aqueous preparation, wherein the aqueous preparation is the aqueous preparation according to claim 1 .

24. The aqueous preparation according to claim 1 , which is preserved relative to bacteria selected from the group consisting of Thermus sp., Propionibacterium sp., Rhodococcus sp., Panninobacter sp., Caulobacter sp., Brevundimonas sp., Asticcacaulis sp., Sphingomonas sp., Rhizobium sp., Ensifer sp., Bradyrhizobium sp., Tepidimonas sp., Tepidicella sp., Aquabacterium sp., Pelomonas sp., Alcaligenis sp., Achromobacter sp., Ralstonia sp., Limnobacter sp., Massilia sp., Hydrogenophaga sp., Acidovorax sp., Curvibacter sp., Delftia sp., Rhodoferax sp., Alishewanella sp., Stenotrophomonas sp., Dokdonella sp., Methylosinus sp., Hyphomicrobium sp., Methylosulfomonas sp., Methylobacteria sp., Pseudomonas sp., and mixtures thereof.

25. The aqueous preparation according to claim 1 , which is preserved relative to bacteria selected from the group consisting of Pseudomonas putida, Pseudomonas mendocina, Pseudomonas fluorescens, Pseudomonas alcaligenes, Pseudomonas pseudoalcaligenes, Pseudomonas entomophila, Pseudomonas syringae, Methylobacterium extorquens, Methylobacterium radiotolerants, Methylobacterium dichloromethanicum, Methylobacterium organophilu, Hyphomicrobium zavarzini, and mixtures thereof.

26. An aqueous preparation of mineral matter at a solids content of 10 to 85% by dry weight relative to the total weight of the aqueous preparation, and as a preservative:

(a) one or more sources of lithium ions in an amount such that the total amount of lithium ions in the aqueous preparation is from 750 to less than 3000 ppm, calculated relative to the water in the preparation, and

(b) one or more sources of sodium ions and/or potassium ions in an amount such that the total amount of sodium ions and/or potassium ions in the aqueous preparation is from 3000 to less than 7500 ppm, calculated relative to the water in the preparation,

wherein the mineral matter consists of ground calcium carbonate, dolomite, ground calcium carbonate surface treated with a fatty acid, surface reacted ground calcium carbonate, or any mixture thereof.

27. The aqueous preparation according to claim 26 , wherein no biocide other than the biocide formed by addition of lithium ions and sodium ions and/or potassium ions is added.

28. A base paper, paper coating or paint formulation prepared from or comprising the aqueous preparation according to claim 1 or a dried form thereof.

29. A plastic, food, feed or cosmetic prepared from or comprising the aqueous preparation according to claim 1 or a dried form thereof.

30. The aqueous preparation according to claim 1 , wherein the mineral material consists of ground calcium carbonate surface treated with a fatty acid or precipitated calcium carbonate surface treated with a fatty acid.

31. The aqueous preparation according to claim 1 , wherein the mineral material consists of surface reacted ground calcium carbonate or surface reacted precipitated calcium carbonate.