At-line X-ray analysis solutions

”Illustration shows integration with automated Epsilon-3 bench-top XRF spectrometer”

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ApplicationFLSmidth’s at-line X-ray analysis solution concept combines high frequency sampling with X-ray fluorescence spectrometry and/or X-ray diffraction for tight on-line chemical quality control of powder/granular process streams. Quality control of cement raw meal by XRF is the main focus application; however, the concept also supports applications like at-line analysis of clinker and cement, as well as other dry powder or granular intermediate/final products in other mineral processes. Heavy Minerals processing is one of these possible applications in other industries.

The concept is a further development of the at-line EDXRF product (QCX/OnStream, OLX800, OLX900) which FLSmidth pioneered the development of several years ago.

The at-line X-ray analysis concept offers a high degree of flexibility. In brief, the concept consists of a sampler (selected for the project specific sampling location) and a Centaurus + X-ray analyser placed under the sampler. The Centaurus, along with customers preferred choice of X-ray fluorescence analyser, is delivered in a container with built-in air conditioning, dedusting unit, sampling control and other utilities.

The flexibility of the concept extends to the type of analytical application too. Both XRF and XRD may be supported, with these key application details:

XRF: Virtually all available and applicable XRF spectrometers from market leading suppliers may be applied. The solution focuses on compact X-ray units such as the Epsilon 3 (automated version of

PANalytical product) and the Optim’X (ThermoFisher product). But also high-end WDXRF spectrometers may be applied if a wider element range and/or very high analytical performance is demanded. Thus, analytical performance and elemental range is determined by the installed XRF spectrometer.

XRD: Again virtually all available and applicable X-ray diffractometers from market leading suppliers may be integrated. The XRD functionality may origin from XRF/XRD combination technologies, offered today by some of the X-ray equipment suppliers. By integrating either one of these combined XRF/XRD models or a more advanced dedicated X-Ray Diffracto-meter (XRD), applying full pattern-based XRD by the Rietveld method, the solution may also serve as an at-line XRD (or at-line XRF/XRD) solution, thereby addressing the growing market interest for this type of application.

Cement applicationsWhile tight quality control of raw meal by XRF no doubt is the main focus application, the flexibility of the at-line X-ray concept supports a wider range of applications analysis and control of intermediate products in the cement making process:

Raw materials: Installed at the bottom of a well functioning stockpile sampling tower the at-line concept can deliver frequent XRF analysis data for optimizing of stockpile feed & quarry operation. In this context, please notice that for stockpile feed monitoring FLSmidth always recommends as first choice Bulk Material Analysers (BMA) based on PGNAA/PFTNAA technology. However, when legislation in a given

FLSmidth pioneered several years ago the use of at-line XRF solutions for tight raw-mix control at cement plants.

The principle of our former at-line XRF solutions was to produce a loosely compacted sample for X-ray analysis without prior sample grinding.

Introducing ‘Centaurus’ (combined laboratory mill & press) FLSmidth’s at-line XRF solution is now based on best practice sample preparation and analytical performance.

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country or customer preference is against the use of nuclear process based measuring technologies, the at-line X-ray solution may be the alternative.

Raw meal: Sampling, preparation and analysis of the raw meal process stream sampled after the raw mill, preferably before return of dust from ESP’s or bag filters. Typically 6-8 cycles per hour. The high sampling frequency and short time from sampling to analysis paves the way for lowest possible quality variations at this key sampling point.

Kiln feed: Sampling, preparation and analysis of the kiln feed sampled after the raw meal silo. Frequent sampling and analysis of kiln feed may be a valuable input for high level kiln control systems, like ECS/ProcessExpert.

Hot meal: Sampling, preparation and analysis of hot meal sampled at the lower stage cyclone. The increasing use of alternative fuel, as well as feed of fine

ground raw materials after the raw mill (fly ash is one example) can make such application interesting as to the analysis of elements like Cl, S, Na and K.

Clinker: Sampling, preparation and analysis of clinker. In addition to provide the analysis values for normal QA purposes, free lime and other cement minerals may be determined by XRD for fast feedback to high level kiln control systems, such as ECS/ProcessExpert. If XRF/XRD combination analysers are applied also elemental analysis value can be reported. A crushing stage located between sampler and the at-line X-ray container will be required to bring the clinker particle size to below 6 mm before introduction to the Centaurus.

Cement: Sampling, preparation and analysis of cement. The objective may be to report elemental analysis (XRF), cement mineral phases (XRD) or both XRF & XRD data and on this basis control the amount of gypsum or other

additives. As to the XRD objective, it is relevant to mention that the Centaurus combined mill & press supports “soft” grinding, by which sample material may be prepared and analysed with minimum de-watering of gypsum phases. The same sampling point may optionally also support on-line fineness analysis (by laser granulometry or Blaine).

If the horizontal distance between the raw mix (mill output) and kiln feed (silo output) sampling points is short, it will be possible with an extra sampler, some extra piping and a Y-piece to have one at-line system analyse both raw mix and kiln feed. In such a set-up, for example 3-5 raw mix sample portions could be anlysed for every kiln feed portion. The results of the latter could be passed on to a high level kiln control system and enhance the automatic control by providing fast info on changes in kiln feed chemistry.

QCX/At-line X-ray solutions

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Other industrial applicationsIn heavy minerals processing, at-line X-ray analysis technology is a well established analytical concept aiming at optimizing the efficiency of the magnetic and electrostatic separation equipment employed. The best practice X-ray sample preparation introduced by the use of Centaurus combined mill & press will further enhance the achievable analytical performance of the application.

FunctionalityThe basic operation principle is that a primary sampler extracts a small by-pass sample stream from the powder process stream. This extraction is normally continuous (3-5 litre/minute), but other concepts may be applied note1. These alternatives include optional collection in a mixer to form a few minutes composite sample prior to secondary sampling. With typically 8-10 minutes interval, a small sample portion (30-50 cc) is taken from the by-pass stream with a secondary sample spoon and delivered to the top of a Centaurus combined laboratory mill & press. The Centaurus fine-grinds the sample material and delivers a steel ring with pressed sample powder for X-ray analysis. Via a small conveyor band, the steel ring is brought to the X-ray device and here automatically loaded to the sample introduction position. The sample is analysed for ½ to few minutes, and the steel ring is subsequently returned to the Centaurus for cleaning. Please refer to the Centaurus Product Profile for more operational details. The analysis time depends on the type of X-ray unit and/or number of elements/mineral phases to be reported. In typical cement raw meal applications, the analyser can process 8-10 samples per hour with an effective 10-12 minute cycle time from sampling to analysis result.

In order to initially calibrate the X-ray analyser, the recommended procedure is to “copy” the calibration applied for the laboratory X-ray set-up at the specific plant. It requires standard sample material be prepared on the Centaurus with same sample preparation recipe as to be used for normal samples, followed by a calibration analysis sequence the X-ray unit. Alternatively a customer may collect calibration samples (typically 6-8 pcs) at site and forward these to FLSmidth for certified analysis and calibration evaluation prior to installation. System componentsExcept for the primary & secondary sampling components and the excess sample return components, the system components

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are located in a robust, air conditioned cabin/container suited for an industrial environment. Asides protecting against dust, rain, direct sun exposure, the protective cabin will provide the specified operational temperature for the X-ray spectrometer.

The total system configuration consists of:

• Projectspecificprimarysamplingsystem,e.g.ascrewsampler, an air-slide sampler or other

• Sampleby-passtubewithsecondarysampledosingdevice

• Excesssamplereturnsystembygravityorforcedviaairconveying

• Automaticcombinedmill&press,makeCentaurus,forX-raysample preparation, including automatic cleaning and excess sample discharging system

• X-rayanalysisunit(XRF,XRDorXRF/XRD)

• Oneinternal‘user’referencesamplepositionforX-raydevicedrift monitoring

• ProgrammableAutomationController(PAC)forcontrolofproject specific sampling equipment, including possible forced return of excess sample material

• Remotediagnosticservicebynetworkconnectionormodem

• Dustproof,air-conditionedcabin(IP54/NEMA).Thecabindimensions (standard size, hwd) are: 2591x3500x2438 mm and it comes with pre-installed air conditioner, lighting and power supplies. Optionally this position may be supplied by the customer, but linked to overall installation & commissioning efficiency it is recommended that the cabin is FLSmidth supply. The container may be supplied with other dimensions

• Dedustingunitplacedunderaroofadjacenttothecabin

All components have been selected with a view to being suitable for reliable operation in a process environment.

Available options include:

• Componentssupportingdual,alternatingsamplingpoints,for example two nearby raw or cement mills or two nearby sampling locations for raw meal and kiln feed

• FLSmidthdeliveryofcalibrationsamples

• Samplesmanuallycollectedfromsamplinglocationsplacednearby the cabin can be introduced manually via a sample entry hatch at the side of the cabin. Sample announcement and identification may be done in two ways: either via a set-up with 3 push-buttons and signal lamps (supporting up to 3 different sample types) or via a rugged Touch Screen QCX Client PC.

• He-purgesystemsforcertainEDXRFanalysers

• CVTunitfornone-standardvoltage

The system components are to be connected via Network cable to a QCX PC placed in the central laboratory/CCR. Same network cable facilitates Internet based communication to FLSmidth’s & X-ray supplier’s service centre. It is the customer’s responsibility to arrange for the network connection and in particular to clear any firewall issues with such connection.

The entire pre-assembled system comes “ready-to-install” with project specific programming of sampling control system, designed for the actual sampling configuration, tested prior to delivery and ready for installation.

Sampling and preparation has a cycle time of typically 7-8 minutes, whereas the analysis time (and reported values) depends on the X-ray unit installed. However, as sample preparation and analysis works in parallel (e.g. next sample may be prepared while current sample is analysed) 7-8 minutes also becomes the typical interval between sample taking.

Note1: When possible, excess sample material from the sample by-pass stream will be fed back to the process stream by gravity. Where gravity return is not applicable, the system design includes components for forced transport of excess sample material to the process stream.

1. Protective cabin Including auxiliaries such as dedusting and air conditioning

2. Centaurus3. X-ray analyser4. Sampling & sample feed controller+ QCX software with raw mix control or

interface to 3rd party equivalent system.

QCX/At-line X-ray solutions

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QCX Control functionality for cement raw meal analysis applicationIna‘traditional’rawmealcontrolloopbased on laboratory XRF analysis with a wavelength dispersive X-ray spectrometer (WDXRF), a new control sample is typically analysed every ½ to 1 hour. With an at-line XRF set-up, the control frequency is typically increased to once every 8-10 minutes. With this higher frequency, the raw mix blending is optimised by the full suite of QCX/BlendExpert-Mill software features. Applying best practice sample preparation, the control loop is self contained, e.g. compared to earlier at-line X-ray solutions from FLSmidth – such as OLX900 – the so-called inner & outer loop control structure is no longer necessary. While not a mandatory requirement, FLSmidth recommends including comparison against laboratory XRF analysis of a representative

The at-line X-ray analysis concept supports a multitude of sampling solutions to suit the project specific details. Screw, air slide or piston samplers are the most commonly employed.

Other supported solutions include dual sampling points as well as a mixing tank installed after the primary sampler so that a few minutes composite sample portion rather than a spot sample is routed to the container.

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composite sample in the raw mix control scenario. The at-line XRF application is based on a series of spot samples taken with some minutes interval. For overall QA & QC purposes, as well as to provide sample material for other tests (moisture, particle size etc), it is still recommendable to take composite samples of the raw meal with 1-2 hours interval and to generate shift or 24hour composite samples. The check against composite samples and/or applying drift monitor checks every 4-8 hours of the at-line XRF device via the available drift monitorsampleswillprovide‘goodlaboratory practice’ in assuring excellent analytical performance of the at-line installation. And in the case of equipment maintenance or malfunction, a simple switching can activate the laboratory XRF based control loop to take over responsibility for the mix control, now based on conventional sampling. This setup provides a robust

QCX/At-line X-ray solutions

structure which is tolerant to errors in any of the two analysis instruments.

Comparative comments on raw meal quality control applicationThe at-line XRF analysis concept is one of more possible technologies delivering tight raw meal quality control. Bulk Material Analysis based on nuclear process based measuring technologies like PGNAA or PFTNAA and placed on the feed stream to a raw mill is another widely applied technology. Both technologies can be regarded as mature with +20 years of application history and several successful installations behind them. One major advantage with the X-ray based at-line technology is that it does not employ any radioactive components. Thus, no time consuming

paper work is involved in obtaining shipping of radioactive sources/neutron tubes, as well as obtaining operational permits for same, which is one of the burdens coming with the nuclear BMAs. While an at-line XRF installation will demand a little higher maintenance work than associated with BMAs, an at-line XRF solution employing a cost effective XRF analyser is available at a lower price than a BMA solution for the same on-line raw mix quality control objectives. In fact, when compared to BMAs, FLSmidth’s new at-line XRF solution for raw mill quality control offers many advantages. Foremost, best practice sample preparation eliminates the need forfrequent‘check’samples(outerloopsamples/bias compensation samples)

employed by most other on-line/at-line analysis applications around the raw mill. In summary, in a comparison with a PGNAA/PFTNAA based QC concept, the at-line XRF solution offers:

• Lowerinitialcapitalinvestment

• Loweroperatingcosts

• Nosafetyissueswithneutronradiation

• Noredtapeassociatedwithneutronsource delivery

• Bestpracticeanalyticalperformance

• Abilitytoanalysead-hocmanually-introduced samples

• Abilitytosupporttwonearbysampling points with one unit

• Evenbettercontrolperformance.

Project Centre Denmark FLSmidth A/SVigerslev Allé 77DK-2500 ValbyCopenhagenTel: +45 3618 1000Fax: +45 3630 1820 E-mail: info@flsmidth.com

Project Centre USAFLSmidth Inc. 2040 Avenue CBethlehem, PA 18017-2188Tel: +1 610-264-6011Fax: +1 610-264-6170E-mail: info-us@flsmidth.com

Project Centre IndiaFLSmidth Private LimitedFLSmidth House34, Egatoor, Kelambakkam(Rajiv Gandhi Salai, Chennai)Tamil Nadu – 603 103Tel: +91-44-4748 1000Fax: +91-44-2747 0301E-mail: indiainfo@flsmidth.com

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Copyright © 2013 FLSmidth A/S. ALL RIGHTS RESERVED. FLSmidth is a (registered) trademark of FLSmidth A/S. This brochure makes no offers, representations or warranties (express or implied), and information and data contained in this brochure are for general reference only and may change at any time.