초록

The present invention refers to a process for preserving an aqueous preparation of mineral material like e.g. calcium carbonate preparations, and to the use of a composition as a preservative in an aqueous preparation of mineral materials.

대표청구항 ▼

1. A process for preserving an aqueous preparation of mineral material, comprising the following steps: (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 consis

1. A process for preserving an aqueous preparation of mineral material, comprising the following steps: (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;(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 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 mineral material so that the aqueous preparation so preserved has a bacterial count of less than 104 cfu/ml. 2. The process according to claim 1, wherein the aqueous preparation has a mineral solids content of 20 to 80%, by dry weight relative to the total weight of the aqueous preparation. 3. The process according to claim 1, wherein the aqueous preparation of step (a) has a pH value of 6 to 10.5. 4. The process according to claim 1, wherein the aqueous preparation of step (a) has a pH value of 7 to 10. 5. The process according to claim 1, wherein the aqueous preparation of step (a) has a viscosity of from 50 to 800 mPa·s. 6. The process according to claim 1, wherein the aqueous preparation of step (a) has a viscosity of from 80 to 600 mPa·s. 7. The process according to claim 1, wherein the mineral material consists of ground calcium carbonate obtained from marble, limestone and/or chalk. 8. The process according to claim 1, wherein the mineral material consists of precipitated calcium carbonate. 9. The process 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 process according to claim 1, wherein the source of the lithium ions is a polymeric salt of lithium selected from Li2Na2polyphosphate, lithium-sodium hexamethaphosphate, and lithium polyacrylate. 11. The process according to claim 1, wherein the source of the lithium ions is lithium carbonate. 12. The process 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 process 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 process according to claim 1, wherein the source of the sodium 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 process according to claim 1, wherein the source of the sodium and/or potassium ions is one or more of sodium carbonate and potassium carbonate. 16. The process according to claim 1, wherein the source of the sodium and/or potassium ions is sodium carbonate. 17. The process according to claim 1, wherein the source of sodium 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 process according to claim 1, wherein the source of the lithium ions of step (b) and the source of the sodium and/or potassium ions of step (c) are added simultaneously to the aqueous preparation of step (a). 19. The process according to claim 1, wherein the source of lithium ions of step (b) and source of sodium and/or potassium ions of step (c) are added separately to the aqueous preparation of step (a). 20. The process 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 and/or potassium ions. 21. The process according to claim 1, wherein when the source of the sodium and/or potassium ions is a polymeric salt, the polymeric salt of one or more of sodium and/or potassium ions is added prior to the source of lithium ions. 22. The process according to claim 1, wherein no biocide other than the biocide formed by addition of lithium ions and one or more of sodium and/or potassium ions is added. 23. The process according to claim 1, wherein after step (c), the aqueous preparation is dried to obtain a dried product. 24. The process 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. 25. The process according to claim 1, wherein the mineral material consists of surface reacted ground calcium carbonate or surface reacted precipitated calcium carbonate.