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The Iron Ore RaceIssue 27 – December 2010

The Iron Ore RaceAuthor: Andrew Okely

It is well recognised that global iron ore demand is growing rapidly,with China the driving force behind this growth. As a result, seaborneexports of iron ore from countries such as Australia and Brazil haveincreased substantially. Australian iron ore production in 2006/07 was253 illi t 1 th j it f hi h t d I 2010

Outotec Australia’s quarterly e-newsletter

Contents 253 million tonnes1, the majority of which was exported. In 2010Australia’s iron ore exports are tipped to reach 400 million tonnes andgrow to more than 900 million by 2017. Such massive growth indemand might lead one to think that there is no competition betweensuppliers, which is far from the truth. The following article outlinessome key competitive forces in Australia’s iron ore supply industry andlooks at how these forces can determine the success of companies inmeeting the present growth demand.

1

Contents

Iron Ore Race: 1

Maximise your recoveries in a flash: 4

Seal your mill’s future: 8

There are many players in the Australian market - Rio Tinto, BHP,Fortescue, Sino Iron, Grange, Crosslands and many others – all ofwhom are accelerating their projects to meet the demand. Each projectcan represent tens of millions of tonnes of iron ore and come fromevery conceivable ore source. The majors, for example, are examininghaematite-based production whilst many juniors are looking atmagnetite-based projects. Either way, with Australia’s local steelindustry unlikely to grow all that iron ore has to be shipped overseas

Pulp level control in flotation circuits

Get SET go: 12

industry unlikely to grow, all that iron ore has to be shipped overseasbefore it can be sold. Therefore, the development of and access to deepwater port infrastructure is crucial.

All of the above will take enormous amounts of limited resources.People, equipment and capital must be secured for any project tosucceed. So the race is on and not everyone will finish. Here are someof the key factors that will determine the winners in this race, witheach factor representing one lap of the courseeach factor representing one lap of the course.

Editor:Laura [email protected]

1. Minerals Council of Australia, Industry Survey Report 2007._________________________________________________________________

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Output Australia | December 2010 |

Iron Ore Train

Lap 1 - Ore SourceIron ores are generally either haematite (Fe203), goethite (Fe203H20) or magnetite (Fe304.).Haematite ores, with grades greater than 57% iron, are known as DSO or Direct Ship Ores and areliterally mined, crushed and shipped. Other types with lower iron contents require processing toupgrade and produce a concentrate. In many cases this upgrading must not only increase the ironcontent but also decrease the level of problem elements such as silica, alumina and phosphorus.

Iron Ore Train

This processing involves the construction of a concentrator which incurs both capital andoperating costs. Thus, as a general rule, the lower the iron grade in the ore source, the higher thecost of production (both capital and operating) so the high grade DSO should grab the lead on thislap.

Lap 2 - Location Location LocationWhen dealing with huge quantities of relatively low value per tonne material, the location of yourmine counts for a lot. How far is a suitable port? Do you have access to rail lines? These issuescan make or break a project. The time and cost to develop port and rail infrastructure will alsodetermine the timeline for a project. So, in this lap, the ability to access existing infrastructurecomes in first place, second place goes to those that control the development of theirinfrastructure allowing a company to work to its timetable. The least desirable position is beingpart of a new multi-party infrastructure development where construction schedule and financingare more difficult to control. It is important to note that all of these scenarios can be successful, itis speed - not ultimate outcome - being considered here.

Lap 3 - The race for capitalIn its simplest form, capital comes from either equity or debt. Again, simplifying things, the biggerthe company, the more its capacity to raise capital for new projects. In the iron ore race thesesimple statements do become more complicated when we consider the demand in China for ironore. With China’s burgeoning iron and steel industries, Chinese steel companies require anincrease in the supply of iron ore, preferably accompanied by greater competition and the

ti f i i th i d t A lt f thi it h b ibl f llpromotion of new companies in the industry. As a result of this, it has been possible for smallcompanies to consider large projects in partnership with Chinese steel companies.



Despite the China influence there are still clear places in this lap First place in the capital lap goes


Despite the China influence, there are still clear places in this lap. First place in the capital lap goesto the big company that effectively self-funds their growth by raising capital on the open market.Second place goes to those who find partners with deep pockets. Third are those smaller companieslooking to put together a mix of debt and equity on their own. Once again we are talking about thespeed with which a project can be developed - not necessarily the likely success, or otherwise, of aproject.

ConclusionSo putting this together - we find that a project with high grade DSO, with access to existing port orrail facilities that is owned by a large company will, in all likelihood, win the race to get tonnes of oreto market. This is a somewhat obvious outcome; the real interest is looking at who might be secondand third in this race, where even a place can lead to a small company becoming a major supplier inthese lucrative times.

Andrew Okely is currently Head of Non Ferrous Solutions for Outotec Australia. He has a bachelorsdegree in Metallurgical Engineering from RMIT, a post graduate certificate in marketing and amasters degree in business finance, both from UNSW.

_______________________________________________________________________________________________

If you would like more information, click here to contact

[email protected]




Maximise your recoveries in a flashAuthor: Rob Coleman

Flash Flotation is the “instantaneous” flotation of liberated, high grade particles from therecirculating load in the grinding circuit. The concept has been around for almost eighty years,although it has only been recently that large scale Flash Flotation circuits have become a reality.The process is widely known however not widely understood This article describes Flash FlotationThe process is widely known however not widely understood. This article describes Flash Flotationand its benefits, the various circuit options and how to determine if Flash Flotation will be suitablefor your ore.

Why does Flash Flotation work so well?As valuable minerals are soft in comparison to the host rock, with a significantly higher solidsdensity, they tend to concentrate in the re-circulating load of the grinding circuit. This can lead tothe over-grinding of the valuable minerals until they report to the cyclone overflow, which in turng g y p ycan lead to lower recoveries in the flotation circuit. In comparison, the flotation conditions aresignificantly better in the cyclone underflow stream than in the cyclone overflow (flotation feed) dueto the presence of fast-floating liberated particles in this stream. The cyclone underflow particlesalso tend to have cleaner, less oxidised surfaces and are not too fine for flotation (i.e. less slimes).Therefore, installing a specially designed flotation cell in the grinding circuit can significantlyimprove plant performance.

There are various Flash Flotation designs in the marketplace, but as this process is quite complex to‘get right’, it is particularly important to chose a supplier with experience and a proven track record.The typical design of Outotec’s Flash Flotation, SkimAir® is shown in Figure 1.

How does Flash Flotation work?The feed to the SkimAir® comes from adistribution box which splits the cycloneunderflow. Typically, one-half to two-thirds of

F d the cyclone underflow stream is diverted intothe SkimAir®, with the remainder of thestream returning to the mill feed. Dilutionwater is also added to the feed to reduce thesolids density to approximately 65%. Althoughoptimal flotation performance is at a lowersolids density, this would require moredilution water, and as the majority of feed

h ili h ddi i l

Feed

Concentrate

reports to the tailings, the additional waterreturns to the mill, reducing the millthroughput. Therefore, it is a balancing actbetween mill throughput and SkimAir®

performance.

Tails

Figure 1: Design of Outotec SkimAir®

The suitably sized particles in the feed are contacted with air in the mechanism the fast-floatingliberated particles are floated to the surface and then recovered to the concentrate. The mass pull toconcentrate is typically only 1-2% and can be of high enough grade to be directly mixed with theconventional circuit final concentrate.




The particles in the feed that are too coarse to suspend and float are segregated to the tailings via aThe particles in the feed that are too coarse to suspend and float are segregated to the tailings via aconical-shaped tank floor. These particles simply by-pass the SkimAir® and return to the mill forfurther grinding. Therefore, the size of the particles in the feed to the SkimAir® can be as large as10mm. In other words, the SkimAir® acts as a flotation cell and a classifier.

Extensive experience requiredThe design of a suitable Flash Flotation cell requires extensive experience. There are many pitfallswhen treating such high solids densities and a wide particle size distribution. These include poorsolids suspension and sanding and inadequate mixing of water and solids in the feedpipe.Additionally, the froth booster cone needs to be correctly sized to ensure the correct concentrateflow and grade is achieved. A poorly operating Flash Flotation circuit can have a significantdetrimental impact on mill throughput and performance.

Benefits of Flash FlotationIt is now clear that the Flash Flotation can prevent the over-grinding of valuable minerals and thegeneration of slimes Another important advantage of using Flash Flotation is that the SkimAir®generation of slimes. Another important advantage of using Flash Flotation is that the SkimAir®

provides a buffer for the conventional flotation circuit when the feed grade is highly variable. Whenfeed grades are high, the SkimAir® can recover the additional metal to produce a more stable feed tothe conventional flotation circuit. This advantage is often overlooked.

As the fast-floating liberated mineral is removed in the grinding circuit, the footprint of a greenfield’sflotation circuit can also be reduced. The SkimAir® concentrate particle size is also coarser thanconventional flotation so when added to the final concentrate it improves concentrate dewatering,lowers filter costs and reduces final concentrate moisturelowers filter costs and reduces final concentrate moisture.

Flash Flotation circuitsThere are two main Flash Flotation circuit options depending on the ore characteristics. The firstmethod is conventional Flash Flotation, where the SkimAir® unit is used as a stand-alone cell toproduce a high-grade concentrate (see Figure 2). The second main method, Flash Roughing™,unique to Outotec, comprises two stages, with the SkimAir® as a rougher, operating at longerresidence times and higher mass pulls so as to produce a lower-grade concentrate at highrecoveries. The SkimAir® concentrate is then treated through an Outotec TankCell® Flash Cleaner™to produce a high-grade concentrate. If the SkimAir® concentrate is high in free gold, a gravityseparation device is installed between the Flash Rougher™ and Flash Cleaner™ to recover free golddirectly to the gold room.

SAGMill

To Flotation

Water Addition

Water Addition

Skim Air

SAG Mill

Ball Mill

New Feed

SkimAir Feed

Cyclone Underflow

SkimAir Concentrate

Figure 2: Conventional Flash Flotation Circuit




Is Flash Flotation right for me?Flash Flotation technology has successfully been applied to the processing of many minerals. WithOutotec’s SkimAir®, for example, there have been significant successes in applications such as gold,platinum group metals, copper, nickel, lead and silver. So, how do you know if your process willbenefit from Flash Flotation? Firstly, you need to perform laboratory flotation tests. With Outotec’sspecially designed test procedure, if the laboratory float shows high recoveries for the valuablemineral (40% to 80%) with low overall mass yields (less than 5%) then Flash Flotation will most likelybe suitable Secondly a good understanding of the ore mineralogy in the cyclone underflow is also abe suitable. Secondly, a good understanding of the ore mineralogy in the cyclone underflow is also anecessity. Lastly, if required, pilot-scale units can be used. Outotec’s pilot-scale units can treatbetween 250 kg/hr and 3 tph of solids. The results can then be modelled using computer simulationsoftware, such as Outotec’s HSC Sim, from which full-scale performance can be predicted.

The results speak for themselves..There have been over 200 SkimAir® units installed in operations world-wide. Some recent casestudies are as follows:

Flash flotation – Gold application Flash flotation – Gold application




SummaryFlash Flotation is not new. The Flash Flotation process is highly complex, so an experienced supplierwith a proven track record can make all the difference. It is an exact science to optimally designFlash Flotation cells to handle such coarse particles with high solids densities, yet still keep themrunning with high availabilities. However for a minimal investment, the performance improvements

b i

Flash flotation - Copper/gold application

can be staggering.

____________________________________________________________________________________________

Dr Rob Coleman is currently Technology Leader – Flotation for Outotec Pty Ltd in Australia. He has aChemical Engineering degree and a Doctorate in Minerals Processing. Rob has over 15 yearsexperience in the operation, modelling and optimisation of flotation circuits.


[email protected]




Author: Jeff BelkeSeal your mill’s future

A mine site is by no means a pristine environment – equipment on site is subjected to continuouscontamination and debris such as dust, oil, water and slurry – often all at the same time. So keeping the‘heart’ of a plant - the grinding mill - well maintained and free from contaminants hazardous to a safe,efficient operation can be a real challenge.

One important mill component which must stay contaminant-free is the lubrication system for the mainsupporting bearings. Contamination here can lead to:

1. Premature wear of the lubrication system components,2. High levels of water in the lubricant and3. Main bearing failure

Given the lubrication system includes the main bearing housings it is vital these housings exclude ingress ofGiven the lubrication system includes the main bearing housings, it is vital these housings exclude ingress ofcontaminants from the environment. An added consideration is that modern environmental legislation isincreasingly adopting a zero tolerance of lubricant leaks from the system. The main bearing housing sealingsystem must therefore not only avoid contamination of the lubrication system but also avoid any leaking oflubricant into the environment.

A significant challengeThese dual sealing requirements havebeen a significant challenge for millbeen a significant challenge for millbuilders and mill owners, since themain bearing housings are often verylarge, with high sealing velocities. Themarketplace, has seen many variants onseals for main bearing housings over theyears. Early designs were simplelabyrinth-style seals, with options suchas extruded style, moulded seals oras extruded style, moulded seals orwrapped pipe-based seals.

These systems have performed fromvery poorly to reasonably, but eachvariant has been flawed in some way.Apart from basic requirements such asensuring contaminants are kept out andl b i t k t i th i t tlubricants are kept in, other importantconsiderations include ensuring the sealspeed capacity is well in excess of theinstalled velocity and that the seal doesnot cause wear to critical millcomponents (especially those difficult to

Grease contamination on inside bearing housing on older style seal

repair, such as axial type sealing systems which run on the mill journal). The seal materials must also betolerant of operating temperature, lubricant type, process fluids and UV. Additionally, the seal design mustb il dj t bl f difi ti d i th i i i d id ll b it bl t b thbe easily adjustable for modifications during the commissioning process and ideally be suitable to bothretrofits and greenfield installations. So, coming up with a design which can manage all theseconsiderations is not as easy as one might think...




Oil leaking from mill bearing housing

Maximum protectionOutotec used the above considerations to guide its design of a new main bearing housing sealing system.The resulting design, Outoseal, is based around Outotec’s proven traditional tip to tip shaft mounted v-ringseal arrangement of a v-ring seal tip sealing against both the front and back of a static plate. This ensuredthe sealing direction was axial, rather than radial, as was the case in many alternative designs. Thistraditional tip to tip solution was often quite complex to install and sometimes liable to movement duringoperation. These shortcomings have now been overcome with the Outoseal, which combines a number ofseparate parts (including the two separate v-seals) into one robust arrangement thereby using internalseparate parts (including the two separate v seals) into one robust arrangement, thereby using internalforces to reduce detrimental seal movement to almost zero. It also uses a simple-to-install o-ring cord tochange the seal lip pressure, instead of having to adjust the seal location relative to the surface.

Maximum benefitsThis new design has many benefits –

1. The lips have minimised contact area with the seal plates, whilst still providing sufficient contactpressure and area to ensure a good sealpressure and area to ensure a good seal.

2. The O-ring cord can be used to vary the contact pressure of the lip on the plate, enablinginstallation variations simply by changing the O-ring cord diameter. This potentially saves manyfrustrating man-hours in the process.

3. The one arrangement mitigates the movement of individual v-seals, which can be detrimental toseal performance.

4. Axial sealing direction - rather than radial - ensuring high tolerance of geometric run-outs andno wearing of the mill journal.g j

5. Flexible arrangement which can be retrofitted to existing mills.




O ti i d l b i ti tOptimised lubrication systemsSeals in operation on mills are subjected to high running speeds and thus require lubrication to ensurethey are not exposed to excessive heat caused by friction. Traditionally, main bearing seals have beenlubricated by grease supplied via a standalone lubrication system; however Outotec’s Outoseals use oilsupplied via the main bearing lubrication system, dispensing with the need for a standalone seallubrication system. Further advantages of this oil lubrication arrangement are:

grease contamination is eliminated from the main bearing lubricantno maintenance – as there is no need to clean or dispose of grease purged from the sealsreduced waste and costs - oil is recycled back to the bearing lubrication system and re-used. Thisoil is conditioned with the main flow of returning bearing oil, thus ensuring any contaminants areremoved before the oil is reused for the bearings and seals.

Integrated flingers

Seal where grease entered bearing housing

Integrated flingersThe Outoseal also incorporates integrated ‘flingers’ on the inboard and outboard sides of the seal,designed to take advantage of the rotational forces to centrifugally spin fluids on the seal away from thesealing surface. The inboard flinger is used to keep bearing lubrication oil away from the inside lip of theseal. The outboard flinger, in combination with the stationary outer labyrinth angle, provides protectionfor the outer seal lip from wash down water, rain, dust, slurry leakage and other contaminants.




ConclusionConclusionThe development of the Outoseal is just one example of why it is so important to speak regularly with yourmill supplier to ensure you are up-to-date with recent design improvements. Although the old sealingdesign may have been previously “acceptable”, recent design optimisations have brought numerousadvantages to sites. So, what may have previously been acceptable to mill owners in terms of lubricantdischarge fines, filter replacement costs, contaminated lubrication replacement, lubrication systemrepairs and downtime costs could now be an unnecessary hit to your bottom line and, a thing of the past…

_______________________________________________________________________________________________

Jeff Belke is Chief Application Engineer - Grinding Mills for Outotec globally. With a degree inmechanical engineering, Jeff has worked in the mining industry for over 17 years, specialising inequipment design and project management. He has been responsible for a number of patents inequipment design. Most recently, Jeff has focused on the engineering aspects of Outotec's grindingmills related to operability, maintainability and development.


[email protected]




Get SET go!

Current economic and environmental constraints compound the need for highly efficient thickenerperformance to yield superior process results. With greater throughputs, less environmental impact andoptimized energy efficiency in mind, a new technology, Shear Enhanced Thickening (SET), has beendeveloped. This article will outline the thickening sedimentation process, the theory of SET and, finally,validation of SET by results from site testwork.

Authors: Chad Loan & Ian Arbuthnot

g

How does sedimentation work?

Flocculant adsorbs onto discrete particlesGrow and loosely bind

into highly porous aggregates

Flocculant adsorbs onto discrete particlesGrow and loosely bind

into highly porous aggregates

Clarification ZoneOverflow

Cla

rifyi

ngTh

icke

ning

Networked compacted pulp bed

Hindered Settling ZoneFree Settling Zone

Consolidation and compression under self-weight forces

Clarification ZoneOverflow

Cla

rifyi

ngTh

icke

ning

Networked compacted pulp bed

Hindered Settling ZoneFree Settling Zone

Consolidation and compression under self-weight forces

Underflow

Aggregates become crowded, impeding each others settling

self weight forcesUnderflow

Aggregates become crowded, impeding each others settling

self weight forces

Within the body of the thickener tank, several zones or layers of varying aggregate composition andsuspension density exist. It is conventionally considered that to achieve an appropriate underflowdensity, the free settling, hindered and networked zones should be largely undisturbed. As the pulp bedincreases in depth, it becomes increasingly difficult for released liquid to permeate through the pulpbed. Dewatering pickets mounted to the rake arms aid removal of such liquid and pickets are typically

Figure 1: Settling zones and processes within a thickener

g p q p yp yarranged at equally spaced intervals to produce dewatering channels. It has also been found that therotation of the rake assembly with pickets increases the possibility of pulp bed rotation, which is alsoknown as “donutting” or “islands”.

The theory of SETFollowing previous studies of applying shear to the hindered settling zone to increase sedimentationrate and compressive yield stress of the pulp bed, Outotec carried out further rigorous modelling andi ti ti t t k f ll i hi h th Sh E h d Thi k i (SET) t h l d l dinvestigative testwork, following which the Shear Enhanced Thickening (SET) technology was developed.




The shear rate applied to aggregates by a moving shearing element is generally expressed by:

ال k / ξ k.ul =ال(1) / ξ ……..(1)

where ال is the shear rate in s-1,ul is the linear velocity of the shearing element in ms-1,ξ is the distance between the shearing element and the aggregate in meters, andk is a constant, which is a function of the material properties of the pulp.

ul = 2pv.ℓ ………(2)

where v is the rotational speed of the shaft in s-1; andℓ is the distance from the center in meters.

Equations (1) and (2) indicate distance from the axis of rotation increases, the linear velocity of theshearing element increases proportionally. Angling the proportionally spaced shearing elements to thevertical plane will result in a substantially uniform cumulative shear being applied to the aggregates bythe time they exit the shear zone.

Validation of SETMany months of dynamic bench scale thickener testwork was used to validate the application of uniformcumulative shear and to determine the resultant impacts on thickener performance and design.Outotec’s testwork units (94mm, 190mm and 1m pilot scale) were modified to incorporate a SETmechanism to provide uniform cumulative shear to the hindered settling zone. The following outlinesthe results from two series of testwork programs (further testwork series available on request) and isthen followed by details on SET installations.y

1. Gold Tailings testworkThe aim of this series of tests was to evaluate the association between flux rate, uniform cumulativeshear and underflow density.

The tests were conducted in the 94mm dynamic thickener under “standard high rate” and “shearenhanced” thickener conditions. Tests ranged in flux rates from 0.5 to 2.0 t/m2h and a rake shaft

t ti l d f 1 d b th t d d d h d diti B th t ithrotational speed from 1 rpm, under both standard and sheared conditions. Both systems ran with aconstant bed height of 500mm.




Following this testwork, it was clear that a higher underflow density for the same thickener size could beachieved. A 40m SET could be used to produce a paste-like underflow of 62%w/w, density far superiorachieved. A 40m SET could be used to produce a paste like underflow of 62%w/w, density far superiorto the 52%w/w from a 57m high rate thickener. For example, if the gold sample tested here required afull-scale underflow density of 52%w/w, a flux rate of 0.5 t/m2h would need to be employed using a highrate thickener. If the proposed plant was to treat 1500 t/h of tailings material, a 62m diameter high ratethickener would be required. However, if the proposed SET technology were to be employed, a flux rateof 2.0 t/m2h or higher could be selected and would result in a 31m diameter SET thickener. If the datawere extrapolated and assuming a linear drop in density, it could be implied that to obtain an underflowdensity of 52%w/w with SET a flux rate of 3.0 t/m2h could be employed. At this flux rate, a SET thickenerof only 25m diameter would be required, versus the 62m high rate thickener.y q , g

Alternatively, and perhaps of more interest to many sites and applications, a higher underflow densityfor the same thickener size could be achieved. That is to say, a 44m SET thickener could be used toproduce a paste-like underflow of 62%w/w, density far superior to the 52%w/w from a 62m high ratethickener.

2. Mineral Sands Slimes testworkA i l d li l t di d it t i d t i l ti Th t t d t dA mineral sands slimes sample was studied on site at an industrial operation. The tests were conductedin a 1m diameter Pilot thickener, at a bed depth of 0.5m. Testing focused on the current operatingconditions at the site, a flux rate of 0.25 t/m2h and an increased flux rate of 0.75 t/m2h.

The graphic outlines the impacts of SETtechnology under pilot scale operation.Standard high rate thickening producedan underflow density of 24%w/w at afl t f 0 25 t/ 2h h SETflux rate of 0.25 t/m2h, whereas SETproduced a density of 35%w/w at 3times the flux rate of 0.75 t/m2h.

As was evident with the previoustestwork, the impact of the results onthickener sizing and design areremarkable. The results indicate thatthe existing thickener could be fittedthe existing thickener could be fittedwith SET technology and produce anunderflow density of 11%w/w higherand this is at a flux rate of 3 times theexisting operating conditions. Theachieved density with SET takes theunderflow into the paste realm fromonly a bed depth of 0.5m, whenconventional understanding is that highconventional understanding is that highbed depths 3-10m are required toachieve paste like underflowsFigure 2: Pilot thickener results

Theory becomes reality – full scale installationsWith such compelling results from testwork, the next step in validation of SET technology is full scaleinstallations. Although still early days, results are extremely promising. At one particular site, Outotecretrofitted a SET mechanism to an existing 8m CCD thickener application The existing high rateretrofitted a SET mechanism to an existing 8m CCD thickener application. The existing high ratethickener produced an underflow density of 45%w/w with a flux rate of 1.33 t/m2h. When the SETmechanism was installed, the underflow increased to 54% w/w and the flux rate was increased 20% to1.61t/m2h. The increase in flux rate was limited to what could be supplied by the existing pipework/feedarrangement and process constraints.




Outotec have also supplied a 24m SET thickener to replace an original order of 2 x 24m paste thickeners. This greenfield installation will be commissioned in 2011. Furthermore, Outotec is also carrying out testwork for other sites, with additional installations in the pipeline.

ConclusionsExperimental investigations of the theories have resulted in some remarkable outcomes. In all workpresented, standard high rate thickening testwork shows a drop in underflow density with increasing fluxrates When uniform cumulative shear is applied the underflow densities remain and also in somerates. When uniform cumulative shear is applied, the underflow densities remain and also, in somecircumstances, increase significantly at up to 3 times the flux rate.

In the series of testwork on mineral sands and gold tailings outlined previously, the SET underflowdensities are all significantly higher than those produced under normal testwork conditions. Theimplications on thickener design sizes are highly significant. As an example, if the data were extrapolatedand assuming a linear drop in density, it could be implied that to obtain an underflow density of 52%w/wwith SET thickening a flux rate of 3.0 t/m2h could be employed. At this flux rate a SET thickener of only25m diameter would be required, versus the 62m high rate thickener. Alternatively, paste-like underflow

Chad Loan is a thickening specialist with Outotec’s Global Thickener Technology group. Chad has spent

_______________________________________________________________________________________________

25m diameter would be required, versus the 62m high rate thickener. Alternatively, paste like underflowcould be produced at higher flux rates with Shear SET technology, without the need for deep sidewallpaste thickeners.

the past nine years working in the minerals processing industry, with particular emphasis on thickeningand flocculation involving a wide range of minerals and applications. He holds First Class Honors inApplied Science from Curtin University, a global patent in thickening and has authored numerouspapers.

Ian Arbuthnot has a wide range of experience in process engineering, acquired over 35 years. Hiscurrent position is Director - Special Projects and Ian is based in Perth. Previous roles have includedgeneral management, sales and marketing, project management and process engineering design. He

/


chad loan@outotec com

has specialised experience in solid/liquid separation including filtration and thickening and has beenresponsible for a number of design patents in this area. Ian has been involved in industries includingmining and minerals processing, water and wastewater treatment and chemical/industrial.

[email protected]

OUTPUT AUSTRALIA EDITOR

Laura White – Marketing Manager, Minerals ProcessingTel: +61 2 9984 2500Email: [email protected]




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