Pellet

Abstract

The invention relates to a process for producing a pellet and a pellet obtainable by said process. The process comprising (i) providing particulate material selected from a carbonaceous material, metal, metal ore, and mixtures thereof; and an inorganic binder comprising a metal silicate, to form a mixture; (ii) compressing the mixture to form a pellet; and (iii) curing the pellet by contacting the pellet with gaseous carbon dioxide. A pellet comprising a particulate material selected from a carbonaceous material, metal, metal ore, and mixtures thereof; silica; and a metal carbonate is also described.

Description

This invention relates to a method for producing pellets and the pellets obtainable by this method. The method includes: (i) providing a pellet material selected from carbonaceous materials, metals, metal ores, and mixtures thereof, and an inorganic binder comprising a metal silicate to form a mixture; (ii) compressing the mixture to form pellets; and (iii) solidifying the pellets by contacting them with gaseous carbon dioxide. A pellet material comprising a pellet material selected from carbonaceous materials, metals, metal ores, and mixtures thereof; silicon dioxide; and a metal carbonate is also described herein.

Claims

Claims1. A process for producing a pellet, the process comprising:(i) providing particulate material selected from a carbonaceous material, metal, metal ore, and mixtures thereof; and an inorganic binder comprising a metal silicate, to form a mixture;(ii) compressing the mixture to form a pellet; and(iii) curing the pellet by contacting the pellet with gaseous carbon dioxide.

2. A process according to claim 1, further comprising addition of an organic binder.

3. A process according to claim 1 or claim 2, wherein the hydraulic pressure applied in step (ii) is applied using a roller pressing process (RPP) in the range 50 Bar to 300 Bar.

4. A process according to claim 1 or claim 2, wherein the pressure applied in step (ii) is applied using a cold-pressing technique (CTS) using a 10 mm die, wherein the pressure applied is in the range 6000 Bar to 8000 Bar calculated under 6 tonnes force.

5. A process according to claim 1 or claim 2, wherein the pressure applied in step (ii) is applied using a cold-pressing technique (CTS) using a 16 mm die, wherein the pressure applied is in the range 2000 Bar to 5000 Bar calculated under 6 tonnes force.

6. A process according to claim 1 or claim 2, wherein the pressure applied in step (ii) is applied using a cold-pressing technique (CTS) using a 20 mm die, wherein the pressure applied is in the range 800 Bar to 3500 Bar calculated under 6 tonnes force.

7. A process according to any preceding claim, wherein the carbon dioxide of step (iii) is carbon dioxide generated from one or more industrial processes.

8. A process according to any preceding claim, further comprising the additional step of capturing carbon dioxide generated from one or more industrial processes for use in step (iii).

9. A process according to any proceeding claim, wherein step (iii) additionally comprises application of heat at a temperature in the range 50°C to 1000°C.

10. A process according to claim 9, wherein the application of heat comprises application of heat generated from one or more industrial processes.

11. A process according to any preceding claim, wherein curing the pellet in step (iii) takes place at atmospheric pressure.

12. A process according to any of claims 1 to 10, wherein curing the pellet in step (iii) takes place at a pressure in the range 1 Bar to 3 Bar.

13. The process according to any preceding claim, wherein the particulate material is added in an amount of about 70 wt% to about 99.9 wt% of the mixture of step (i).

14. The process according to any preceding claim, wherein the particulate material comprises a metal ore, a metal, and combinations thereof.

15. A process according to claim 14, wherein the particulate material comprises iron.

16. A process according to any of claims 13 to 15, wherein the particulate material comprises a carbonaceous material.

17. A process according to any preceding claim, wherein the particulate material has a moisture content of less than 25%.

18. A process according to any preceding claim, wherein the metal silicate is present in the mixture in the range 0.5 wt% to 5 wt% of the mixture.

19. A process according to any preceding claim, wherein the metal silicate comprises a group I or group II metal silicate.

20. A process according to any preceding claim, wherein the metal silicate is selected from sodium silicate (NazSiCh), calcium silicate (CaSiCh, CazSiC ), potassium silicate (KzSiCh), magnesium silicate (MgSiC ), and combinations thereof.

21. A process according to any preceding claim, wherein the metal silicate is selected from sodium silicate, potassium silicate, magnesium silicate, and combinations thereof.

22. A process according to any preceding claim, wherein the metal silicate is selected from sodium silicate, magnesium silicate, and combinations thereof.

23. A process according to any preceding claim, wherein the metal silicate is selected from potassium silicate, magnesium silicate, and combinations thereof.

24. A process according to any of claims 2 to 23, wherein the organic binder is present in the mixture in the range 0.2 wt% to 5 wt% of the mixture.

25. A process according to any of claims 2 to 24, wherein the organic binder comprises a natural polymer, a synthetic polymer, a glycerolipid, a cellulosic material, a polysaccharide, and combinations thereof.

26. A process according to claim 25, wherein the organic binder comprises a polyacrylamide resin, a phenol formaldehyde resin, a polyacrylic, a styrene-acrylate polymer, cellulosic fibres, carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), hydroxyethyl methyl cellulose (MHEC), glyceryl triacetate, glyceryl diacetate, polyvinyl alcohol, wheat starch, maize starch, barley starch, potato starch, gum Arabic, guar gum, xanthan gum, and combinations thereof.

27. A process according to claim 25 or claim 26, wherein the organic binder comprises a polyacrylamide resin, a phenol formaldehyde resin, cellulosic fibres, carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), hydroxyethyl methyl cellulose (MHEC), glyceryl triacetate, glyceryl diacetate, polyacrylamide, ethyl acrylate styrene (EA), polyvinyl alcohol, and combinations thereof.

28. A process according to any of claims 25 to 27, wherein the organic binder comprises a polyacrylamide resin, a phenol formaldehyde resin, cellulosic fibres, carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), hydroxyethyl methyl cellulose (MHEC), polyvinyl alcohol, glyceryl triacetate, and combinations thereof.

29. A process according to any of claims 25 to 28, wherein the organic binder comprises from polyacrylamide resin, cellulosic fibres, carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), and combinations thereof.

30. A process according to any of claims 25 to 29, wherein the organic binder comprises carboxymethyl cellulose (CMC), cellulosic fibres, hydroxyethyl methyl cellulose (MHEC), and combinations thereof.

31. A process according to any of claims 25 to 30, wherein the organic binder comprises carboxymethyl cellulose (CMC).

32. A process according to any of claims 25 to 28, wherein the organic binder comprises polyvinyl alcohol.

33. A process according to any of claims 2 to 32, wherein the organic binder is of viscosity in the range 3,000 to 16,000MPa-s.

34. A process according to any preceding claim, further comprising the addition of a flux additive to the mixture.

35. A process according to claim 34, wherein the flux additive is selected from silica, dolomite, fluorite, calcium oxide, magnesium oxide, carbon, aluminium, dunnite, basalt, and combinations thereof.

36. A process according to claim 35, wherein the flux additive is selected fluorite, aluminium, dunnite, basalt and combinations thereof.

37. A process according to any preceding claim, wherein curing of the pellet by contacting the pellet with gaseous carbon dioxide occurs by introducing the pellets into a gas stream comprising carbon dioxide at a flow rate in the range 1 to 100 litres per minute.

38. A pellet obtainable by a process according to any preceding claim.

39. A pellet comprising a particulate material selected from a carbonaceous material, metal, metal ore, and mixtures thereof; silica; and a metal carbonate.

40. A pellet according to claim 39, wherein the metal carbonate is formed by reaction with an inorganic binder comprising a metal silicate and gaseous carbon dioxide.

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