Method for dry grinding a material containing a carbonate ore
View Patent ↗The present invention is directed to a method for dry milling a material containing a carbonate ore. The method comprises the following steps: (a) dry milling the material in at least one milling unit: (i) in the presence of at least one polyalkylene glycol polymer having monomer units forming a backbone, where at least 90% of the monomer units forming the backbone of the polymer are constituted by ethylene oxide, propylene oxide or their mixtures, and where the polymer has a molecular weight of at least equal to 400 g/mole, (ii) such that the milling unit contains a quantity of water that is less than 10% in dry weight of the material in the milling unit; (b) optionally classifying the material from step a) with at least one classification unit; and (c) optionally repeating steps a) and/or b) with all or part of the material from step a) and/or step b).
1. A method for dry milling a material containing a carbonate ore, wherein the method comprises the following steps:
a) dry milling the material in at least one milling unit:
(i) in the presence of at least one polyalkylene glycol polymer having monomer units forming a backbone, where at least 90% of the monomer units forming the backbone of the polymer are constituted by ethylene oxide, propylene oxide or their mixtures, and where the polymer has a molecular weight of at least equal to 400 g/mole,
(ii) such that the milling unit contains a quantity of water that is less than 10% in dry weight of the material in the milling unit;
b) optionally classifying the material from step a) with at least one classification unit;
c) optionally repeating steps a) and/or b) with all or part of the material from step a) and/or step b).
2. The method according to claim 1 , wherein at least 95% of the monomer units forming the backbone of the polymer are constituted by ethylene oxide, propylene oxide or their mixtures.
3. The method according to claim 1 , wherein at least 98% of the monomer units forming the backbone of the polymer are constituted by ethylene oxide, propylene oxide or their mixtures.
4. The method according to claim 1 , wherein each milling unit contains 0.01 to 0.5% in dry weight of the polymer in proportion to the dry weight of the material containing carbonate ore.
5. The method according to claim 1 , wherein each milling unit contains between 0.1 and 1 mg of the polymer per m 2 of the material containing a carbonate ore.
6. The method according to claim 1 , wherein when the polyalkylene glycol polymer is subjected to a temperature of 45° C. for a period of 16 hours, more than 75% of 50 mg of the polyalkylene glycol polymer placed in 50 ml of water are not volatilised.
7. The method according to claim 1 , wherein the polyalkylene glycol polymer is a glycol polyethylene in which over 95% of its monomers are ethylene oxide monomers, and wherein the polymer has a molecular weight of between 500 and 10,000 g/mol.
8. The method according to claim 1 , wherein the polyalkylene glycol polymer is a glycol polyethylene in which over 98% of its monomers are ethylene oxide monomers, and wherein the polymer has a molecular weight of between 500 and 10,000 g/mol.
9. The method according to claim 1 , wherein the polyalkylene glycol polymer is a glycol polypropylene in which over 95% of its monomers are propylene oxide monomers, and wherein the polymer has a molecular weight of between 500 and 6,000 g/mol.
10. The method according to claim 1 , wherein the polyalkylene glycol polymer is a glycol polypropylene in which over 98% of its monomers are propylene oxide monomers, and wherein the polymer has a molecular weight of between 500 and 6,000 g/mol.
11. The method according to claim 1 , wherein the polyalkylene glycol polymer is an ethylene oxide and polypropylene oxide copolymer.
12. The method according to claim 11 , wherein the copolymer has an ethylene oxide:
propylene oxide ratio of between 1:5 and 5:1.
13. The method according to claim 11 , wherein the copolymer has an ethylene oxide:
propylene oxide ratio of 3:2.
14. The method according to claim 11 , wherein the copolymer has a molecular weight of between 1,000 and 5,000 g/mol.
15. The method according to claim 11 , wherein the copolymer is a block copolymer which includes at least one block of glycol polyethylene and/or glycol polypropylene homopolymer, representing at least 20% of the total of the ethylene oxide and propylene oxide monomer units.
16. The method according to claim 11 , wherein the copolymer is a block copolymer which includes at least one block of glycol polyethylene and/or glycol polypropylene homopolymer, representing at least 30% of the total of the ethylene oxide and propylene oxide monomer units.
17. The method according to claim 11 , wherein the copolymer is a block copolymer which includes at least one block of glycol polyethylene and/or glycol polypropylene homopolymer, representing at least 40% of the total of the ethylene oxide and propylene oxide monomer units.
18. The method according to claim 1 , wherein a mixture of glycol polyalkylene polymers is used.
19. The method according to claim 18 , wherein the said mixture contains at least 2 glycol polyethylene polymers, at least one glycol polypropylene polymer and at least one block copolymer polymer, with an ethylene oxide: propylene oxide ratio of between 90:10 and 10:90.
20. The method according to claim 1 , wherein the polyalkylene glycol polymer is mixed with agents which are not glycol polyalkylenes, and wherein the polyalkylene glycol polymer represents at least 50% by weight of the total weight of the polyalkylene glycol polymer and the non glycol polyalkylene agents.
21. The method according to claim 1 , wherein the polyalkylene glycol polymer is mixed with agents which are not glycol polyalkylenes, and wherein the polyalkylene glycol polymer represents at least 86% by weight of the total weight of the polyalkylene glycol polymer and the non glycol polyalkylene agents.
22. The method according to claim 1 , wherein the polyalkylene glycol polymer is mixed with agents which are not glycol polyalkylenes, and wherein the polyalkylene glycol polymer represents at least 95% by weight of the total weight of the polyalkylene glycol polymer and the non glycol polyalkylene agents.
23. The method according to claim 22 , wherein the non glycol polyalkylene agent is a carbohydrate, tri-isopropyl amine, or mixtures thereof.
24. The method according to claim 23 , wherein the carbohydrate is a sucrose, a sorbitol, or mixtures thereof.
25. The method according to claim 1 , wherein the material containing a carbonate ore contain at least 80% of carbonate ore in proportion to the weight of the material.
26. The method according to claim 1 , wherein the material containing a carbonate ore contain at least 90% of carbonate ore in proportion to the weight of the material.
27. The method according claim 1 , wherein the carbonate ore is dolomite, calcium carbonate or mixtures thereof.
28. The method according to claim 27 , wherein carbonate ore is calcium carbonate selected from limestone, marble, chalk, precipitated calcium carbonate or mixtures thereof.
29. The method according to claim 27 , wherein carbonate ore is calcium carbonate selected from limestone, marble or mixtures thereof.
30. The method according to claim 1 , wherein the material containing a carbonate ore has a median diameter before stage a) of between 0.2 and 0.7 mm, as measured using sieves.
31. The method according to claim 1 , wherein stage b) takes place.
32. The method according to claim 1 , wherein at least 2 classification stages take place before a further stage a), and in that one or other of these 2 stages may occur in series or in parallel.
33. The method according to claim 31 , wherein part of the material from the classification stage b) is recirculated back to stage a) for further milling.
34. The method according to claim 31 , wherein the material from stage b) has an equivalent spherical diameter of between 0.7 and 150 μm.
35. The method according to claim 1 , characterised in that a new amount of material containing carbonate ore is added to stage a).