Alkaline earth carbonate containing mineral for surface cleaning
The present invention relates to a dry blasting process for the cleaning of solid surfaces as well as special abrasive pigments suitable therefor and a method for their production.
1. A process for cleaning a solid surface comprising the steps of:
(a) obtaining natural alkaline earth carbonate particles having a mean particle diameter of from 100 to 500 μm, a Mohs hardness of below 4, and classified as providing a residue on a 500 μm sieve of ≦10 wt.-%, a residue on a 200 μm sieve of from 20 to 60 wt.-%, a residue on a 90 μm sieve of from 50 to 95 wt.-%, and a residue on a 45 μm sieve of ≧90 wt.-%; and
(b) dry blasting the surface with the natural alkaline earth carbonate particles from step (a) to clean the surface.
2. The process according to claim 1 , wherein the natural alkaline earth carbonate particles comprise natural calcium carbonate and/or natural calcium magnesium carbonate.
3. The process according to claim 1 , wherein the natural alkaline earth carbonate particles comprise marble, calcite, chalk, dolomite, limestone, or any mixture thereof.
4. The process according to claim 1 , wherein the natural alkaline earth carbonate particles comprise marble.
5. The process according to claim 1 , wherein the natural alkaline earth carbonate particles comprise marble containing dolomite.
6. The process according to claim 1 , wherein the natural alkaline earth carbonate particles have an average Mohs hardness of from 2.6 to 3.9.
7. The process according to claim 1 , wherein the natural alkaline earth carbonate particles have an average Mohs hardness of from 2.6 to 3.4.
8. The process according to claim 1 , wherein the alkaline earth carbonate content in the natural alkaline earth carbonate particles is >90 wt.-%.
9. The process according to claim 1 , wherein the alkaline earth carbonate content in the natural alkaline earth carbonate particles is 95 to 99.9 wt.-%.
10. The process according to claim 1 , wherein the natural alkaline earth carbonate particles have a calcium content of at least 21 wt.-%.
11. The process according to claim 1 , wherein the natural alkaline earth carbonate particles have a calcium content of >35 wt.-%.
12. The process according to claim 1 , wherein the natural alkaline earth carbonate particles have a calcium content of >38 wt.-%.
13. The process according to claim 1 , the natural alkaline earth carbonate particles have a magnesium content of maximum 13 wt.-%.
14. The process according to claim 1 , the natural alkaline earth carbonate particles have a magnesium content of <3 wt.-%.
15. The process according to claim 1 , the natural alkaline earth carbonate particles have a magnesium content of <1.5 wt.-%.
16. The process according to claim 1 , wherein the natural alkaline earth carbonate particles comprise dolomite in a content of 0.1 to 100 wt.-%.
17. The process according to claim 1 , wherein the natural alkaline earth carbonate particles comprise dolomite in a content of 2 to 10 wt.-%.
18. The process according to claim 1 , wherein the natural alkaline earth carbonate particles comprise dolomite in a content of 3 to 7 wt.-%.
19. The process according to claim 1 , wherein the natural alkaline earth carbonate particles are classified as providing a residue on a 500 μm sieve of ≦8 wt.-%.
20. The process according to claim 1 , wherein the natural alkaline earth carbonate particles are classified as providing a residue on a 500 μm sieve of ≦5 wt.-%.
21. The process according to claim 1 , wherein the natural alkaline earth carbonate particles are classified as providing a residue on a 500 μm sieve of 3 to 4 wt.-%.
22. The process according to claim 1 , wherein the natural alkaline earth carbonate particles are classified as providing a residue on a 200 μm sieve of from 25 to 50 wt.-%.
23. The process according to claim 1 , wherein the natural alkaline earth carbonate particles are classified as providing a residue on a 200 μm sieve of from 30 to 40 wt.-%.
24. The process according to claim 1 , wherein the natural alkaline earth carbonate particles are classified as providing a residue on a 90 μm sieve of from 70 to 92 wt.-%.
25. The process according to claim 1 , wherein the natural alkaline earth carbonate particles are classified as providing a residue on a 90 μm sieve of from 73 to 90 wt.-%.
26. The process according to claim 1 , wherein the natural alkaline earth carbonate particles are classified as providing a residue on a 45 μm sieve of ≧93 wt.-%.
27. The process according to claim 1 , wherein the natural alkaline earth carbonate particles are classified as providing a residue on a 45 μm sieve of ≧95 wt.-%.
28. The process according to claim 1 , wherein the natural alkaline earth carbonate particles are classified as providing a residue on a 45 μm sieve of from 97 to 99 wt.-%.
29. The process according to claim 1 , wherein 50 to 80 wt.-% of the natural alkaline earth carbonate particles have a particle size of between 90 to 500 μm.
30. The process according to claim 1 , wherein 60 to 80 wt.-% of the natural alkaline earth carbonate particles have a particle size of between 90 to 500 μm.
31. The process according to claim 1 , wherein the natural alkaline earth carbonate particles have a median particle diameter of from 110 to 400 μm.
32. The process according to claim 1 , wherein the natural alkaline earth carbonate particles have a median particle diameter of from 130 to 300 μm.
33. The process according to claim 1 , wherein the natural alkaline earth carbonate particles have a median particle diameter of from 135 to 200 μm.
34. The process according to claim 1 , wherein the natural alkaline earth carbonate particles have a median particle diameter of from 137 to 165 μm.
35. The process according to claim 1 , wherein the natural alkaline earth carbonate particles have a median particle diameter of from 142 to 160 μm.
36. The process according to claim 1 , wherein the natural alkaline earth particles are obtained by dry grinding.
37. The process according to claim 1 , wherein the natural alkaline earth particles are obtained by dry grinding in a ball mill or hammer mill.
38. The process according to claim 1 , wherein the natural alkaline earth particles are obtained by dry grinding in combination with the use of cyclones and sieves.
39. The process according to claim 1 , wherein the solid surface is cleaned of a material selected from the group consisting of paints, food residues and pharmaceutical residues.
40. The process according to claim 1 , the solid surface is steel, glass, wood, or concrete.
41. The process according to claim 1 , wherein the alkaline earth carbonate particles are applied at 1 to 90° relative to the surface to be cleaned.
42. The process according to claim 1 , wherein the alkaline earth carbonate particles are applied at 30 to 90° relative to the surface to be cleaned.
43. The process according to claim 1 , wherein the alkaline earth carbonate particles are applied at 40 to 90° relative to the surface to be cleaned.
44. The process according to claim 1 , wherein the alkaline earth carbonate particles are applied at 60 to 90° relative to the surface to be cleaned.
45. A process for manufacturing natural alkaline earth carbonate particles useful for dry blasting a surface comprising the steps of dry crushing, dividing and/or grinding natural alkaline earth carbonate having an Mohs hardness of below 4 to obtain a medium particle diameter of from 100 to 500 μm, and screening the natural alkaline earth carbonate to obtain a natural alkaline earth carbonate that is classified as providing a residue on a 500 μm sieve of ≦10 wt.-%, a residue on a 200 μm sieve of from 20 to 60 wt.-%, a residue on a 90 μm sieve of from 50 to 95 wt.-%, and a residue on a 45 μm sieve of ≧90 wt.-%.