Process for wet high intensity magnetic separation with flux amplifying matrix
A method, process or system for producing an iron oxide concentrate from a treatment slurry of a low grade mineral assemblage includes mixing a flocculant with the treatment slurry and dewatering the treatment slurry before passing the treatment slurry through a wet high intensity magnetic separator of a type that employs a flux amplifying matrix (i.e., a WHIMS-FAM device) and recovering an iron oxide concentrate fraction and a tailings fraction from the WHIMS-FAM device. Another method, process or system for producing an iron oxide concentrate includes passing the treatment slurry through a WHIMS-FAM device and recovering an iron oxide concentrate fraction slurry and a tailings fraction slurry from the WHIMS-FAM device; mixing a flocculant with the concentrate fraction slurry and dewatering the concentrate slurry to provide a thickened concentrate slurry before filtering the thickened concentrate slurry to provide a concentrate filter cake.
1. A method for producing an iron oxide concentrate, comprising:
mixing into a treatment slurry including a particulate low grade mineral assemblage suspended in water a flocculant comprising a synthetic anionic polyacrylamide polymer to provide a mixture, wherein the flocculant is mixed with the treatment slurry in an amount to provide a flocculant concentration in the mixture of from about 1 ppm to about 10 ppm on a weight to weight basis of the flocculant relative to the particulate low grade mineral assemblage in the treatment slurry;
increasing a ratio of the particulate low grade mineral assemblage to water in the mixture in a dewatering device, recovering overflow water from the dewatering device and recovering a thickened slurry from the dewatering device;
introducing the thickened slurry into a wet high-intensity magnetic separation device, the wet high-intensity magnetic separation device defining a slurry flow path that contains a flux amplifying matrix, and the wet high-intensity magnetic separation device operable to generate a high intensity magnetic field having flux lines that pass through the slurry flow path; and
recovering a final concentrate fraction and a final tailings fraction from the wet high-intensity magnetic separation device;
wherein the final concentrate fraction comprises an iron oxide concentrate.
2. The method in accordance with claim 1 wherein said mixing comprises mixing the flocculant into the treatment slurry before the mixture is introduced into the dewatering device.
3. The method in accordance with claim 1 wherein said mixing comprises mixing the flocculant into the treatment slurry in the dewatering device.
4. The method in accordance with claim 1 wherein the particulate low grade mineral assemblage includes ultrafine particles and wherein the flocculant is mixed into the treatment slurry in an amount effective to achieve diversion of a majority of the ultrafine particles from the overflow water to the thickened slurry recovered from the dewatering device.
5. The method in accordance with claim 1 wherein the flocculant is mixed into the treatment slurry at a concentration of from about 1 ppm to about 8 ppm.
6. The method of claim 1 wherein the treatment slurry is substantially free from magnetite particles.
7. A method for producing an iron oxide concentrate comprising:
mixing a flocculant into a treatment slurry including a particulate low grade mineral assemblage suspended in water to provide a mixture;
increasing a ratio of the particulate low grade mineral assemblage to water in the mixture in a dewatering device, recovering overflow water from the dewatering device and recovering a thickened slurry from the dewatering device;
introducing the thickened slurry into a wet high-intensity magnetic separation device, the wet high-intensity magnetic separation device defining a slurry flow path that contains a flux amplifying matrix, and the wet high-intensity magnetic separation device operable to generate a high intensity magnetic field having flux lines that pass through the slurry flow path; and
recovering a final concentrate fraction and a final tailings fraction from the wet high-intensity magnetic separation device;
wherein the final concentrate fraction comprises an iron oxide concentrate.
8. The method in accordance with claim 7 wherein said mixing comprises mixing the flocculant into the treatment slurry before the mixture is introduced into the dewatering device.
9. The method in accordance with claim 7 wherein said mixing comprises mixing the flocculant into the treatment slurry in the dewatering device.
10. The method in accordance with claim 7 wherein the particulate low grade mineral assemblage includes ultrafine particles and wherein the flocculant is mixed into the treatment slurry in an amount effective to recover a majority of the ultrafine particles in the thickened slurry.
11. The method in accordance with claim 7 wherein the flocculant is mixed into the treatment slurry at a concentration of from about 1 ppm to about 10 ppm.
12. The method in accordance with claim 7 wherein the flocculant is mixed into the treatment slurry at a concentration of from about 1 ppm to about 8 ppm.
13. The method of claim 7 wherein the treatment slurry is substantially free from magnetite particles.
14. The method of claim 7 wherein the flocculant comprises a synthetic polymer flocculant.
15. The method of claim 7 wherein the flocculant comprises an anionic polymer flocculant.
16. The method of claim 7 wherein the flocculant comprises a polyacrylamide polymer.
17. The method of claim 16 wherein the polyacrylamide polymer comprises an anionic polyacrylamide.
18. The method of claim 7 wherein the flocculant comprises a non-selective flocculant.
19. The method of claim 7 wherein the flocculant is operable to flocculate iron ore particles in the treatment slurry.
20. The method of claim 7 wherein said mixing and increasing comprises introducing the flocculant into the dewatering device through a first inlet positioned near a second inlet for conveying the treatment slurry into the dewatering device.
21. The method of claim 7 , wherein said increasing comprises passing the mixture through a deslimer and recovering an underflow from the deslimer, wherein the underflow of the deslimer comprises the thickened slurry.
22. The method of claim 7 wherein the dewatering device is selected from the group consisting of hydro-cyclones, spiral classifiers, thickeners, clarifiers, vacuum filters, pressure filters, multi-roll filters, centrifuges and elutriator sumps.
23. The method of claim 7 , wherein the treatment slurry comprise non-magnetically susceptible particles and weakly magnetically susceptible particles.
24. The method of claim 23 , wherein the non-magnetically susceptible particles comprise silica and the weakly magnetically susceptible particles comprise iron minerals other than magnetite.
25. The method of claim 7 , wherein the flux amplifying matrix comprises a plurality of discrete objects.
26. The method of claim 25 , wherein the plurality of discrete objects comprise a member selected from the group consisting of steel shot and iron shot.
27. The method of claim 7 , wherein the flux amplifying matrix comprises wire mesh having significant magnetic susceptibility.
28. The method of claim 7 , wherein the treatment slurry comprises iron ore tailings generated by a mineral processing plant.
29. The method of claim 28 , wherein the mineral processing plant comprises a plant selected from the group consisting of a natural ore wash plant, a taconite mineral beneficiation plant, and a natural ore heavy media plant.