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View additional product information for GS Omni Analyzer - FAQs (GSOMNI)
13 product FAQs found
Justifying any decision around online analysis requires careful and fair consideration of the associated upside.
For a decision around dedicated sampling/analysis stations for a new build, we recommend making a conservative estimate of savings in materials and not underestimating the value of time. A few months' saving on the construction timeline translates directly into an earlier swing from expenditure to income, an inflection point that cannot come soon enough for most projects.
For process control, consider the current situation to determine the magnitude of possible gains. For example:
- What is a recovery improvement worth for your process?
- If you could reduce impurities in the concentrate, what would that mean for selling price?
- What’s the difference in flotation reagent consumption, best to worst current case? What would be the savings if you consistently hit the best case?
- How much are you overmilling over milling to avoid overly coarse material exiting the grinding circuit? What would be the energy savings if you weren’t? Online analysis should pay its way, and easily, so calculations such as these should readily highlight optimal areas for economic implementation and provide evidence to support investment.
In the grinding circuit, under-grinding typically means poor metal recovery (mineral processing) or sub-standard product (cement). Over-grinding, on the other hand, drives up energy consumption and results in undesirable levels of fines. Milling just enough, balances these competing impacts. Online real-time particle sizing analysis makes it possible both to identify an optimal setpoint for particle size and then reliably maintain it.
In a flotation plant, there is an analogous balance to establish. Poor separation means excessive metal loss while excessive reagent addition is expensive and environmentally undesirable. Here, real-time elemental analysis can provide the information needed to identify the operational sweet spot and optimal control in the face of changes in particle size, ore mineralogy, and pulp density.
In both cases, with real-time data, changes tend to be more frequent but smaller, i.e., the plant stabilizes, with automated control minimizing variability.
If you are aiming for automated process control, then that is only practical with high availability and 95% should be an absolute minimum. Otherwise, switching to and from manual process control will be arduous and problematic with respect to operational efficiency. If availability is not demonstrably high, then operators cannot rely on an analyzer, whether control is manual or automated, and it never becomes an integral part of the control architecture.
When implementing online analysis, there are two key questions to consider: What can I measure? And what can I control to affect that measurement?
Let’s take grinding circuit control as an example. A measurable variable is the particle size of the exiting material, and it can be controlled by parameters such as mill throughput and speed of rotation. How often to measure is then the next question. With manual control, a large interval between measurements inhibits an operator’s ability to adjust the process effectively. There is a long lag between taking action and seeing the result. Increasing measurement frequency, to the limit of real-time measurement, improves feedback allowing the operator to learn how to 'steer' the circuit more effectively. The result will be steadier operation with an automated, well-tuned control loop, the best solution for driving variability to a minimum.
If you can measure and tightly control a vital characteristic of a key stream, in a grinding or flotation circuit, or elsewhere on the plant, then the rewards can be substantial. If you can’t influence a measurable parameter, then there is far less impetus to measure it at all, or with any frequency, though measurement may still be valuable for upset monitoring. Focus on how you would use data if you had it to identify the best places for investment and the frequency of measurement that will be most useful.
Well-designed dedicated analyzers require only minimal cleaning and maintenance for reliable operation over the long-term. The sample transport associated with centralized systems, on the other hand, requires the addition of pumps and small-bore sample lines adding additional complexity and failure points to the system. These have potential to affect data availability and cost of ownership due to the maintenance, running costs, and emissions associated with pump operation. Such systems are often installed with good intentions and a sound understanding of the practice required to keep them in good working order, but over the years, enthusiasm and rigor have tended to dwindle. Abandoned lines are common with centralized analyzers, an important point to note when assessing upfront CAPEX.
The other significant difference between multi-stream and dedicated analyzers is measurement frequency. For streams that justify real-time measurement, or as close as is feasible, dedicated analyzers are unbeatable.
If you have the freedom of a new build, then it’s vital to be aware of the broader ramifications of choosing dedicated slurry sampling and analysis stations which are linked with the criticality of head loss and pumping costs. All slurry sampling is associated with head loss, but it can be minimized by selecting a dedicated, low pressure drop sampler with integral analyzer to deliver lower plant heights and/or less pumps. With the smart use of dedicated stations, it is therefore possible to save on construction materials (concrete and steel) and costs, and at the same time shorten project timelines. These are major gains. In contrast, centralized analyzers, however good, necessitate a more complex process flow diagram with all the inefficiencies that go along with it.
Key features are source type/strength and detector size/quality since these define measurement uniformity across the belt and data quality. More powerful sources mean higher neutron counts, in effect, a higher signal, while multiple sources provide more uniform coverage across the belt. Larger or better-quality detectors more effectively capture gamma rays released by the sample with multiple detectors enabling more uniform capture across the belt.
To maximize the value of a cross belt analyzer for a specific application, you should therefore look for flexibility and performance with respect to both source and detector with a view to optimizing for either repeatability or uniformity across the belt, depending on which is more important. Weight, size, and ease of installation are also critical factors when it comes to the practicalities of installing an analyzer.
PFTNA/PGNAA offers moderate to excellent detection capability for industrially relevant lighter elements such as calcium, chlorine, sulfur, aluminum, silicon, magnesium, sodium, and hydrogen which are less easily detected by XRF. Elements with an atomic number of 20 or less release fluorescent X-rays that are less energetic, relative to heavier elements, and therefore more easily attenuated, which makes XRF more challenging in slurry.
PTFNA and PGNAA are both neutron activation analyses which means measurement is reliant on a neutron source. With PTFNA, the source is an electrical neutron generator while with PGNAA, it is a radioactive isotope such as Californium 252. Other than neutron source, which affects suitability for certain applications, the two techniques are essentially identical.
The Thermo Scientific GS Omni Light Element PGNAA Analyzer can measure up to 8 streams and is designed to measure light elements that XRF cannot measure. Combined with a Thermo Scientific XRF analyzer, our online elemental analyzer portfolio allows customers to measure a broader range of elements than any other competitor product on the market.
Yes, our team of plant design engineers can help design a solution around your space constraints. Utilizing integrated products that deliver two functions within the footprint of one product is the key to this, alongside of dedicated analyzers with small footprint and low head loss.
Before selecting an online slurry analysis system, consider if light elements will need to be measured and if the measurement technique is amenable, given the expected variation in mineralogical and particle size for the process. In addition, look at the streams to be measured and ask these questions:
- What is critical for control of process (usually includes Feed, Final Tail, and Concentrate)?
- Is there a need for understanding trends within the process (usually includes Rougher Concentrate and Cleaner Tails)?
- What are the elements to be measured in each stream?
Based on this information, the various trade-offs taking into account all factors between centralized and dedicated analyzers, Prompt Gamma Neutron Activation Analysis (PGNAA) and X-ray fluorescence (XRF), capital and maintenance cost etc., can be worked out and a recommendation made for the optimum system configuration for the particular plant
For example, in a nickel concentrator, it is essential to control the concentration of talc (or MgO) in the concentrate stream. To be able to control the concentration of talc in the concentrate, one requires measurement of Ni and talc in each of the feeds, rougher concentrate, and final concentrate streams so that the appropriate concentration gradients between these can be optimized and the ratio of Ni/talc can be maximized at each stage for minimum reagent usage. It may also be useful to measure Fe and S in the feed stream because this may give an indication of the nickel mineralogy entering the plant. In all other streams, it is only necessary to measure Ni because the information from these streams is used only for monitoring the recovery of Ni. Thus, PGNAAA would be required with multiplexing for the three main streams, and possibly a multi-stream analyzer (using XRF technology) for the other streams).
When selecting the right online slurry analysis system, there are several capital constraints that should be considered, including
- Capital investment,
- Economic benefits expected
- Cost of on-going maintenance
- Flexibility of system modules
- Incremental benefits of less essential assays.
The economic benefits of having an on-line slurry analysis system coupled to a control system, be it manual or fully automatic, comes from one or more of the following: increase in metal recovery, improvement in concentrate grade and control of impurities, reduction in reagent consumption, decrease in operating costs, and improvement in stability of the operation.
These benefits have to be weighed against the capital investment of the analysis system and the cost of on-going maintenance including mechanical repairs, sample pump servicing or replacement, sample transport system troubleshooting, electronic repairs, analyzer downtime and calibration. The flexibility of hybrid systems of dedicated analyzers for the critical streams and multi-stream analyzers for the less critical streams enables the most cost effective analysis system to be selected for each particular plant. In working out what streams are to be measured, a cost benefit analysis should be carried out to guide the decision making process.