AU2010306060B2

AU2010306060B2 - Method for processing manganese ore fines

Info

Publication number: AU2010306060B2
Application number: AU2010306060A
Authority: AU
Inventors: David Michael Geraghty
Original assignee: Process Minerals International Pty Ltd
Current assignee: Process Minerals International Pty Ltd
Priority date: 2009-10-14
Filing date: 2010-01-13
Publication date: 2014-08-07
Anticipated expiration: 2030-01-13
Also published as: AU2010306060A1; WO2011044608A1; AP2012006263A0; ZA201201629B; UA101457C2

Abstract

A method (10) for the processing of manganese ore fines, the method characterised by the steps of: (i) Preparation of a manganese ore fines feed (12) to produce at least two fractions thereof (14, 16); (ii) Passing the larger of the two fractions (16) to a dense medium cyclone circuit (18), incorporating a densifier (20) that is fed from cyclone overflow (22); (iii) Passing the smaller of the two fractions (14) to a density control circuit (24) to remove a sub-fraction (26) below about minus 10 µm and provide a slurry at relatively constant density for subsequent processing steps; (iv) Passing the slurry from step (iii) to a wet high intensity magnetic separation ("WHIMS") circuit (28); (v) Passing the product of the WHIMS circuit (28) to a dewatering step (30); and (vi) Combining the product from the dewatering step (30) and the dense medium cyclone circuit (18) as a final product (32).

Description

WO 2011/044608 PCT/AU2010/000012 "Method for Processing Manganese Ore Fines" Field of the Invention The present invention relates to a method for the processing of manganese ore fines. More particularly, the process of the present invention is intended for use in 5 the processing of manganese ore fines in the range of minus 1.2 mm, including material minus 500 pm. Background Art Traditionally, the tailings produced from manganese ore processing operations have been considered a waste material as traditional industry standard 10 processing techniques have been unable to economically process this finer material to a saleable grade. Particularly, manganese ore tailings material at minus 500 micron is considered a beneficial waste and is typically discharged into tailings storage facilities rather than being directed to further processing to produce a saleable product. An example of such an arrangement is in place at 15 the Bootu Creek manganese mine, Northern Territory, Australia. The process of the present invention has as one object thereof to substantially overcome the problems associated with the prior art described hereinabove, or to at least provide a useful alternative thereto. Throughout this specification, unless the context requires otherwise, the word 20 "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. Reference to cited material or information contained in the text should not be understood as a concession that the material or information was part of the 25 common general knowledge or was known in Australia or any other country.

PCT/AU2010/000012 Received 04/08/2011 -2 Disclosure of the Invention In accordance with the present invention there is provided a method for the processing of manganese ore fines, the method characterised by the steps of: (i) Preparation of a manganese ore fines feed to produce at least two size 5 fractions thereof; (ii) Passing the coarser of the two fractions to a dense medium cyclone circuit, incorporating a densifier that is fed from cyclone overflow; (iii) Passing the finer of the two fractions at a density of greater than about 10% solids to a density control circuit to remove a sub-fraction below about 10 minus 10 pm and provide a slurry at relatively constant density for subsequent processing steps; (iv) Passing the slurry from step (iii) to a wet high intensity magnetic separation ("WHIMS") circuit; (v) Passing the product of the WHIMS circuit to a dewatering step; and 15 (vi) Combining the product from the dewatering step and the dense medium cyclone circuit as a final product. Preferably, step (i) may comprise feed from either dry feed or from tailings, or may be a combination of both. Step (i) is arranged such that a combination of feeds may be achieved in any desired proportions. 20 Still preferably, step (i) also provides a bypass system in which the capture of recoverable ore is able to be achieved when necessary. With regard to feed from tailings, step (i) preferably further comprises a dewatering or thickening step to remove excess water and ultrafine material from the feed. This dewatering or thickening step is preferably used to manage the 25 density of the tailings feed. Still preferably, the density of the underflow material AMENDED SHEET

TPFA/ATT

PCT/AU2010/000012 Received 04/08/2011 -3 from this dewatering or thickening step is measured and controlled by programmable logic controller ("PLC"). The preferred density of this underflow material is between about 34 to 42 weight percent solids. Step (i) further comprises the passing of this underflow material to a wet 5 screening step for size classification or to a dewatering step and stockpiling for later use, or a combination of the two depending upon the requirements of the method from time to time. Preferably, the wet screening step produces at least a minus 500 pm fraction and a fraction between about 500pm to 1.2 mm. Still preferably, a plus 1.2 mm 10 fraction is also produced. The plus 1.2 mm fraction may be passed to a scrubber and returned to the wet screening step. The dense medium cyclone circuit of step (ii) preferably further comprises a low intensity magnetic separation ("LIMS") step that receives a proportion of the material from the densifier. An underflow from the LIMS step is preferably 15 returned for further processing and not directly to tailings or waste. The density control circuit of step (iii) preferably produces a slurry at about 32 42% solids. The feed to the density control circuit is preferably at a density of about 10 to 45% solids. Preferably, the density control circuit comprises a thickener that is able to remove 20 minus 10 pm material and provide a slurry as feed to the WHIMS circuit of step (iv) at the preferred density. Still preferably, the density control circuit further comprises two stage settling matts. Yet still further, a WHIMS middling fraction from step (iv) may be recycled to the density control circuit. 25 The WHIMS circuit of step (iv) preferably comprises at least two stages, being rougher and cleaner. A third stage, scavenger, may also be provided. AMENDED SHEET TDU A /A T T WO 2011/044608 PCT/AU2010/000012 -4 Preferably, each WHIMS circuit stage produces a magnetic fraction, a non magnetic fraction and a middling fraction. Still preferably, the magnetic faction product of the rougher WHIMS stage may be passed either to final product or to the cleaner WHIMS stage. Further, the non 5 magnetic fraction may be passed to either WHIMS tails or to the scavenger WHIMS stage. Still further, the middlings fraction may be returned to the rougher WHIMS stage or passed to the scavenger WHIMS stage. The dewatering step of step (v) preferably comprises a dewatering screen classifier. Still preferably, the dewatering screen classifier comprises a settling 10 hopper having dispersant velocity mats arranged above a screw of the classifier. Brief Description of the Drawings The process of the present invention will now be described, by way of example only, with reference to one embodiment thereof and the accompanying drawing, in which: 15 Figure 1 is a schematic "flow-sheet" for a method for processing manganese ore fines in accordance with the present invention. Best Mode(s) for Carrying Out the Invention In Figure 1 there is shown a method 10 for the processing of manganese ore fines in accordance with the present invention. The method 10 comprises: 20 (i) A feed preparation step 12 in which a manganese ore fines feed is processed to produce at least a minus 500 pm fraction 14 and a fraction 16 between about 500 pm and 1.2 mm; (ii) A dense medium cyclone circuit 18, incorporating a densifier 20 that is fed from cyclone overflow 22, to which the 500 pm to 1.2 mm fraction from the 25 feed preparation step 12 is passed; WO 2011/044608 PCT/AU2010/000012 -5 (iii) Passing the minus 500 pm fraction 14 to a density control circuit 24 to remove a sub-fraction 26 below about minus 10 pm and provide a slurry at relatively constant density for subsequent processing steps; (iv) Passing the slurry from the density control circuit 24 to a wet high intensity 5 magnetic separation ("WHIMS") circuit 28; (v) Passing the product of the WHIMS circuit 28 to a dewatering step 30; and (vi)Combining the product from the dewatering step 30 and the dense medium cyclone circuit 18 as the final product 32. The feed preparation step 12 comprises feed from either dry feed 34 or from 10 tailings 36, or may be a combination of both. The feed preparation step 12 is arranged such that a combination of feeds may be achieved in any desired proportions. A bypass system 38 in which the capture of recoverable ore is able to be achieved when necessary is also provided. Such captured ore from the bypass system 38 is passed to a feed stockpile 40. 15 Delivery of the dry feed 34 to a wet screen 42 of the feed preparation step 12 utlises a traditional feed bin, belt feeder, conveyor and slurry pulping box. Delivery of the tailings 36, having a density of between about 0 to 45% solids, comprises a dewatering or thickening step, for example a dewatering cone/thickener, to remove excess water and ultrafine material from the tailings 20 feed. Excess water/ultrafine material is removed using an overflow launder and gravitates to a collection sump for disposal or reuse elsewhere in the method 10. . This dewatering or thickening step is used to manage the density of the tailings feed. The density of the underflow material from this dewatering or thickening step is measured and controlled by an adjustable valve in turn controlled by a 25 programmable logic controller ("PLC"). The preferred density of this underflow material is between about 24 to 36 weight percent solids.

WO 2011/044608 PCT/AU2010/000012 -6 The feed preparation step 12 further comprises the passing of this underflow material to the wet screen 42 of a wet screening step for size classification or to the bypass system 38 in turn comprising a dewatering step and passing to the stockpiles 40 for later use, or a combination of the two depending upon the 5 requirements of the method 10 from time to time. It is envisaged that the dewatering or thickening step may be operated with or without the addition of flocculant. Additionally, water may be added to the dewatering or thickening step so as to maintain the preferred underflow density. In addition to the minus 500 pm fraction and the fraction of about 500 pm to 1.2 10 mm, the wet screening step 42 also produces a plus 1.2 mm fraction 44, or a screen oversize fraction. The plus 1.2 mm fraction 44 may be passed to a scrubber 46 and returned to the wet screening step 42. The screen matt sizes used in the set screening step 42 will be dependent upon the ore type being processed by the method 10. However, indicative ranges are 15 18 to 1.2 mm on the top deck and 0.8 to 0.3 mm on the bottom deck. The dense medium cyclone circuit 18 further comprises a low intensity magnetic separation ("LIMS") step 46 that receives a proportion of the material from the densifier 20. An underflow 48 from the LIMS step 46 is returned to the circulating medium 50 for further processing rather than being sent to tailings as typically 20 occurs in prior art methods. The dense medium cyclone circuit 18 utilises a plurality of 100 mm cyclones 52 that produce in turn the cyclone overflow 22 and a cyclone underflow 54. As noted above, the cyclone overflow 22 is used to feed the densifier 20, unlike prior art processes in which the circulating medium is used as the feed to the densifier. 25 The dense medium cyclone circuit 18 operates substantially on material obtained from the feed 34 and/or 36 as the medium, requiring fresh Ferrosilicon (FeSi) to be added to maintain a consistent medium density as required by the plant operator.

WO 2011/044608 PCT/AU2010/000012 -7 The density control circuit 24 produces a slurry 56 at about 32-42% solids whereas the density control circuit feed 58, the minus 500 pm fraction from wet screening 42, is at a density of about 10 to 45% solids. The density control circuit 24 comprises a constant density tank or thickener 60 5 that is able to remove any minus 10 pm material 26 and provide the slurry 56 as feed to the WHIMS circuit of step (iv) at the preferred density. The density control circuit 24 further comprises two stage settling mats. In addition, a WHIMS middling fraction from the WHIMS circuit 28 can be recycled to the density control circuit 24. 10 The WHIMS circuit 28 of step (iv) comprises at least two stages, being rougher 62 and cleaner 64. A third stage, scavenger 66, is also provided. Each WHIMS circuit stage 62, 64 and 66 produces a magnetic fraction, a non magnetic fraction and a middling fraction. The non-magnetic fraction from both rougher 62 and cleaner 64 WHIMS stages is directed to the scavenger stage 66. 15 The non-magnetic fraction from the scavenger stage 66 is sent to tailings 68. The magnetic fraction of the cleaner stage 64 becomes the WHIMS product 70. The magnetic fraction of the rougher stage 62 may be recirculated or may be passed to the cleaner stage 64. Each stage 62, 64 and 66 may be operated in either an open or a closed circuit. 20 For example, the magnetic faction product of the rougher WHIMS stage 62 may be passed either to the final product 70 or to the cleaner WHIMS stage 64. Further, the non-magnetic fraction may be passed to either WHIMS tails 68 or to the scavenger WHIMS stage 68. Still further, the middlings fraction may be returned to the rougher WHIMS stage 62 or passed to the scavenger WHIMS 25 stage 68. It is envisaged that design improvements in the WHIMS rotors and feed box may lead to improvements in recovery, in part due to an ability to operate with an increased magnetic strength operating range.

WO 2011/044608 PCT/AU2010/000012 -8 The dewatering step 30 of step (v) comprises a dewatering screen classifier. The dewatering screen classifier comprises a settling hopper having dispersant velocity mats arranged above a screw of the classifier. This arrangement is understood to provide a 3% mass improvement in recovery over traditional 5 arrangements. As can be seen from the above description, the method 10 of the present invention allows recovery of a final manganese product 32 from what has previously been considered a waste material. Modifications and variations such as would be apparent to the skilled addressee 10 are considered to fall within the scope of the present invention.

Claims

1. A method for the processing of manganese ore fines, the method characterised by the steps of: (i) Preparation of a manganese ore fines feed to produce at least size 5 two fractions thereof; (ii) Passing the coarser of the two fractions to a dense medium cyclone circuit, incorporating a densifier that is fed from cyclone overflow; (iii) Passing the finer of the two fractions at a density of greater than about 10% solids to a density control circuit to remove a sub-fraction 10 below about minus 10 pm and provide a slurry at relatively constant density for subsequent processing steps; (iv) Passing the slurry from step (iii) to a wet high intensity magnetic separation ("WHIMS") circuit; (v) Passing the product of the WHIMS circuit to a dewatering step; and 15 (vi)Combining the product from the dewatering step and the dense medium cyclone circuit as a final product.

2. A method according to claim 1, in which step (i) comprises feed from either dry feed or from tailings, or a combination of both.

3. A method according to claim 1 or 2, in which step (i) is arranged such that 20 a combination of feeds may be achieved in any desired proportions.

4. A method according to any one of the preceding claims, in which step (i) also provides a bypass system in which the capture of recoverable ore is able to be achieved when necessary. AMENDED SHEET PEA/AUJ PCT/AU2010/000012 Received 04/08/2011 - 10

5. A method according to any one of the preceding claims, in which step (i) further comprises a dewatering or thickening step to remove excess water and ultrafine material from the feed should the feed be from tailings.

6. A method according to claim 5, wherein the dewatering or thickening step 5 is used to manage the density of the tailings feed.

7. A method according to claim 5 or 6, the density of the underflow material from the dewatering or thickening step is measured and controlled by programmable logic controller ("PLC").

8. A method according to claim 7, in which the density of this underflow 10 material is between about 34 to 42 weight percent solids.

9. A method according to claim 7 or 8, in which step (i) further comprises the passing of the underflow material to a wet screening step for size classification, or to a dewatering step and stockpiling for later use, or a combination of the two. 15

10.A method according to any one of the preceding claims, in which the wet screening step produces at least a minus 500 pm fraction and a fraction between about 500pm to 1.2 mm.

11. A method according to claim 10, in which the wet screening also produces a plus 1.2 mm fraction. 20

12.A method according to claim 11, in which the plus 1.2 mm fraction is passed to a scrubber and returned to the wet screening step.

13.A method according to any one of the preceding claims, in which the dense medium cyclone circuit of step (ii) further comprises a low intensity magnetic separation ("LIMS") step that receives a proportion of the material 25 from the densifier. AMENDED SHEET flU A /AT T