Pellet

Abstract

A method of producing a pellet, the method comprising the steps of: providing a particulate substrate selected from a metal ore, metal ore-containing waste, metal fines, iron residue, iron filings, mineral waste, carbonaceous material, arc furnace waste or combinations thereof; mixing the particulate substrate with a binder formulation comprising at least one binding material to form a substrate mixture; applying pressure to the substrate mixture to induce the formation of a hydrogel; and forming an agglomerate wherein water is present to facilitate hydrogel formation. Together with a pellet obtained by the method of the invention.

Description

Abstract: A method for preparing ore pellets, the method comprising the following steps: providing a granular substrate selected from metal ores, metal-bearing ore waste, metal powder, iron slag, iron filings, mineral waste, carbonaceous materials, electric arc furnace waste, or combinations thereof; mixing the granular substrate with an adhesive formulation containing at least one binder to form a substrate mixture; applying pressure to the substrate mixture to induce the formation of a hydrogel; and forming aggregates containing water to promote hydrogel formation. The pellets obtained by the method of the present invention.

Claims

Claims1. A method of producing a pellet, the method comprising the steps of: a. providing a particulate substrate selected from a metal ore, metal ore- containing waste, metal fines, iron residue, iron filings, mineral waste, carbonaceous material, arc furnace waste or combinations thereof; b. mixing the particulate substrate with a binder formulation comprising at least one binding material to form a substrate mixture; c. applying pressure to the substrate mixture to induce the formation of a hydrogel; and d. forming an agglomerate wherein water is present to facilitate hydrogel formation.

2. A method according to claim 1, wherein at least one binding material is hydrogel forming.

3. A method according to claim 1 or claim 2, wherein the binder formulation comprises two or more binding materials.

4. A method according to any preceding claim, wherein a first and a second binding material are mixed with the particulate substrate to form the substrate mixture.

5. A method according to any of claims 1 to 3, wherein a first binding material is mixed with the particulate substrate to form the substrate mixture, and a second binding material is mixed with the hydrogel.

6. A method according to any preceding claim, wherein applying pressure to the substrate mixture to induce the formation of a hydrogel comprises passing the substrate mixture through compressive wheels.

7. A method according to any preceding claim, wherein the force applied is in the range 11 kN and 75 kN.

8. A method according to any preceding claim, comprising a step of forming a pellet from the agglomerate.

9. A method according to claim 8, wherein the step of forming the pellet comprises passing the agglomerate through rollers comprising a series of evenly spaced recesses along their length.

10. A method according to claim 8 or claim 9, wherein, following the step of forming the pellet, the method comprises the step of heating the pellet to a temperature in the range 10°C to 250°C.

11. A method according to any preceding claim, comprising granulating the agglomerate prior to pelletisation.

12. A method according to claim 11, wherein granulation comprises the use of screen sizes in the range about 1.75 mm to about 10 mm.

13. A method according to any preceding claim, wherein the particulate substrate comprises water in the range of from about 0.5 wt% to about 10 wt%.

14. A method according to claim 13, wherein the particulate substrate comprises water in the range of from about 1 wt% to about 6 wt%.

15. A method according to any preceding claim, wherein the particulate substrate comprises a metal.

16. A method according to any preceding claim, wherein the particulate substrate comprises iron.

17. A method according to any preceding claim, wherein the particulate substrate is provided in an amount of about 70 wt% to about 99.9 wt% of the pellet.

18. A method according to any preceding claim, wherein the binding material is selected from a natural polymer, a synthetic polymer, a cellulosic material, a glycerolipid, a polysaccharide, an inorganic binding material or combinations thereof.

19. A method according to claim 18, wherein the binding material is selected from cellulosic fibres, carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), hydroxyethyl methyl cellulose (MHEC), a polyacrylamide resin, polyvinyl alcohol, a phenol formaldehyde resin, a glycerolipid, a polyacrylic, a styrene-acrylate copolymer, one or more silicates, or combinations thereof.

20. A method according to claim 18 or claim 19, wherein the binding material is selected from cellulosic fibres, carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), a polyacrylamide resin, polyvinyl alcohol, one or more silicates, polyacrylamide, ethyl acrylate styrene (EA), glyceryl triacetate, glyceryl diacetate, a phenol-formaldehyde resin or combinations thereof.

21. A method according to any of claims 18 to 20, is selected from cellulosic fibres, carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), polyvinyl alcohol, a polyacrylamide resin, one or more silicates, polyacrylamide, a phenol-formaldehyde resin, glyceryl triacetate, or combinations thereof.

22. A method according to any of claims 18 to 21, wherein the binding material is selected from a polyacrylamide resin, polyvinyl alcohol, a phenol formaldehyde resin, carboxymethyl cellulose (CMC), glyceryl triacetate, sodium silicate, magnesium silicate, or combinations thereof.

23. A method according to any of claims 18 to 22, wherein the binding material is selected from a polyacrylamide resin, polyvinyl alcohol, a phenol formaldehyde resin, carboxymethyl cellulose (CMC), sodium silicate, magnesium silicate, or combinations thereof.

24. A method according to any of claims 18 to 23, wherein the binding material comprises a combination of a) one or more of carboxymethyl cellulose, cellulosic fibres, PVA and polyacrylamide and b) one or more of a silicate and phenol formaldehyde.

25. A method according to any preceding claim, wherein the binder formulation is added in the amount of about 0.05 wt% to about 6.0 wt% of the pellet.

26. A method according to any preceding claim, further comprising the step of adding a separate processing aid to the substrate mixture.

27. A pellet obtained by the method of any preceding claim, comprising a particulate substrate selected from a metal ore, metal ore-containing waste, metal fines, iron residue, iron filings, mineral waste, carbonaceous material, arc furnace waste or combinations thereof and a binder formulation.

28. A pellet according to claim 27, wherein the pellet is heated to a temperature in the range 10°C to 250°C.

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