Composition measurement can be performed using high specification Prompt Gamma Neutron Activation Analysis (PGNAA) for coal analysis in coke-making, sinter analysis in iron-making as well as scrap steel analysis in steel-making. Moisture can also be measured in coal and sinter using microwave transmission and in coke, sinter, magnetite concentrate, and scrap steel using fast neutron and gamma transmission.
All these technologies measure continuously through the full conveyed depth and provide results in real time directly to the plant control system and all analysis data is owned by the client. Remote access ensures onsite time is minimised and support is readily available if needed. All analysers can be installed during planned shutdowns and no interruptions to operations are anticipated throughout the life of the analysers which have no contact with conveyed flows and no wear components or consumable spare parts.
Representative sampling of bulk materials can prove unreliable due to segregation of materials by particle size, layering, or density variations and the required sample size and frequency to minimise sampling errors. Effective sampling is still required for analyser calibration and therefore a suitable sampling protocol should be developed to address these issues. Online analysers require calibration checks every six months so any sampling required can be made manageable through good planning and implementation and need not interfere with normal production.
Technologies – elemental analysis
The GEOSCAN-S and COALSCAN 9500X are combined with Scantech’s TBM microwave moisture analyser (on suitable materials) and utilise a belt weigher input to calculate tonnage-weighted average dry basis elemental and moisture results over a short analysis period to the plant control system. The GEOSCAN-S can be configured to measure over shorter or longer time increments depending on the application. Where bulk sorting is required, short analysis, say every 30 seconds, provides optimal selectivity, whereas for blending purposes a longer measurement time of perhaps five minutes may be appropriate. Typically results are reported every 1 or 2 minutes with high accuracy due to the customised calibration for each material and application. The GEOSCAN-S has a patented no belt contact design and has no wear components, ensuring minimal maintenance requirements as well as complete safety through careful design of the shielding and access. No isolation area is usually required around the GEOSCAN-S during normal operation in most countries. Figure 1 shows a GEOSCAN-S on a sinter feed conveyor.
COALSCAN 9500X is the elemental technology used for blending coals prior to coke-making to ensure elemental and ash content is controlled. The ash content is measured to a better than 0.5 % total ash precision and individual elements such as sulphur, iron, calcium and others are measured accurately based on the customised calibration for the composition ranges expected.
Technologies – moisture analysis
TBM moisture measurement using microwave transmission allows coal, iron ores and sinter blends to be measured, typically to accuracies better than 0.5 % moisture. Attenuation and phase shift (group delay) are measured using microwaves transmitted through the full conveyed flow depth to indicate the presence of free moisture in the material. Moisture content can also affect the process performance and measurement may also assist with dust management or dry tonnage basis calculations.
The CM 100-S (Figure 2) measures moisture using fast neutron and gamma transmission in materials where the microwave technology is not suitable. T he CM 100-S effectively measures the hydrogen content directly to enable moisture measurement to accuracies of better than 0.3 % moisture over each measurement interval of a few minutes. It can be used for measuring moisture in magnetite iron ores and concentrates and coke. Many installations in Asian and Australian steel plants have proven very successful in coke moisture measurement.
Applications – coal, coke-making
Applications – iron ore, sintering, scrap steel
Scantech is the world’s leading supplier of PGNAA analysers to the iron ore sector with well over 50 successful installations with most major iron ore companies. Standard applications involve the measurement of iron ore quality each two minutes and the systems are located at mines to measure ore produced to reconcile with mine plans, on overland conveyors to divert direct shipping quality ore (DSO) to bypass unnecessary beneficiation, on process feed streams, on product streams, on discard streams, and on train and ship loading flows to manage ore quality throughout the mining, processing and materials handling stages. There is no reason that iron ore supplied to iron-making operations does not meet specification as the analysers are well accepted as the best solution for quality management. All GEOSCAN-M units are installed with TBM moisture analysers as standard.
Moisture measurement using TBM has accompanied the GEOSCAN-S installations. The loss of control in sinter chemistry has been known to result in freezing of furnaces and significant cost in furnace remediation work and downtime causing lost production valued in millions of dollars per day. The addition of an analyser and improved sinter quality management can eliminate this risk. In such cases analyser payback can be measured in hours or even minutes.
High specification PGNAA can also be applied to scrap steel to determine purity and contamination levels so that these may be appropriately managed. CM 100-S can be used in scrap steel for moisture measurement.
Scantech PGNAA analysers are the highest specification available in the market and well proven in many industries. The customised approach to challenging applications has made the GEOSCAN the premium technology for representative real time elemental measurement in the minerals sector. Higher quality measurements (e.g. precisions) enable tighter process control and improved outcomes. Scantech’s philosophy of Rocks2data ensures that customised analyser configurations and calibrations produce the most useful, timely data possible to meet each client’s measurement requirements for effective process control.
Zero contact technologies are available for representative, high precision and frequent multi-elemental measurement as well as moisture measurement to ensure operations in the steel industry for coke-making, iron-making and steel-making can be suitably optimised. The application of these real time measurement technologies is proven to create more sustainability in operations by reducing energy and raw material inputs and increasing process efficiencies and product quality. Many of the world’s largest resources companies have adopted the technologies in various applications to not only improve sustainability but also to demonstrate responsible resource management to their stakeholders.
Henry Kurth, Chief Marketing Officer and Minerals Consultant
Scantech International Pty Ltd, Adelaide/Australia, firstname.lastname@example.org
Henry Kurth has a degree in Geology from Queensland Institute of Technology (now QUT − Qld University of Technology) and has 15 years’ experience in mining geology roles in coal, gold and base metals operations. The next 7 years were in technical sales roles to the resources sector and the last 14 years with Scantech where he leads the global minerals marketing and sales functions in his current role as Chief Marketing Officer and Minerals Consultant. He has been a member of the AusIMM for over 35 years and is a member of the SME in USA and CIM in Canada. Henry Kurth has presented at more than 25 major minerals conferences and workshops on real time analysis technology applications.
Dr Luke Balzan, Chief Technical Officer
Scantech International Pty Ltd, Adelaide/Australia, email@example.com