Despite their humble name, base metals – such as nickel, copper, iron, and zinc – are just as precious and important to society as their flashier relations of gold and silver. In fact, many of the base metals are becoming more valuable than ever before, thanks to the global energy transition supported by advances in battery technology. Within a couple of decades, everyday items from books and watches to cars and trucks have become battery-powered – and base metals, including nickel, are making it possible.
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The mining dilemma
If this sounds like a great opportunity for nickel miners, it is – but it comes with a significant challenge, too. Demand for metals might be projected to keep increasing, but there’s little point in transitioning to cleaner energy if our batteries are produced at a huge cost to the planet. This means that mining has a serious dilemma. We need to produce more metals while drastically reducing our environmental impact at the same time.
There are many innovative solutions currently under development to help global industry become more sustainable – and many of these solutions will make a huge impact in the future. But as one of the most energy- and emissions-heavy industries in the world, mining can’t afford to wait. We need ways to increase productivity while reducing environmental impact today – in other words, we need maximum efficiency. And that’s where on-line analysis comes in.
On-line control
In the past, samples were taken from mined ores and kiln feeds to be analyzed in laboratories for quality control. These processes used standard laboratory techniques, which were often destructive of the sample – resulting in waste – as well as time-consuming and expensive. Although they gave useful information about quality, the lengthy delay of hours or even days before results were reported meant that this data was useless for process control.
Today, advances in technology and on-line analysis have seen a shift away from quality-focused control to process control. Quality remains vital, but now it’s easy to measure in real time thanks to cross-belt analyzers like the CNA Pentos and other on-line instruments. The new frontier is process control, where maximizing efficiency becomes a real target rather than an impossible idea.
Avoiding operational hazards
However, some of these earlier on-line instruments came with downsides. Running analysis in an enclosed laboratory setting means that all staff are highly trained and aware of how to operate the instrument, but in a busy mine or processing plant, a much wider variety of employees might interact with the instrument. Radiation from continuously running analyzers became a serious hazard until more advanced technology was developed, such as pulsed fast and thermal neutron activation (PFTNA).
PFTNA uses an electrical neutron source to provide highly representative real-time elemental analysis of material, generally passing through the analyzer on a belt. This is especially relevant in mining applications, when low-grade ores may be mistakenly discarded as waste without sufficiently accurate analysis. The electrical neutron source can be switched off easily for maintenance or whenever required, making PFTNA much safer for use in a production or processing environment compared with always-on instruments.
Adding value in nickel mining
Highly accurate analysis adds significant value in nickel mining. The predominant source of nickel is lateritic ores, which generally contain only a small percentage of nickel by weight. Separating nickel from the abundant iron content takes care and precision to avoid waste, and is a resource-intensive process. PFTNA technology makes this initial analysis for sorting, grading, and blending ore much easier, not only due to its high sensitivity but also thanks to the real-time results that are returned.
At the PT Vale site in South Sulawesi, Indonesia, plans are underway to install a CNA Pentos cross-belt analyzer for this exact application – thanks to great results already delivered later in the process. A CNA Pentos instrument has already been in use monitoring the kiln feed for several years, ensuring that the level of nickel in the dry kiln product is maintained at ~1.91%, as well as tracking moisture content. The new instrument will enable PT Vale to combine their low- and high-recovery ores at the stockpile without compromising the consistency of their raw material.
This also brings extra value in today’s climate of high energy costs, as other elements such as cobalt, lead, and copper can also be detected at very low levels – making it easier for producers to avoid wasting even small amounts of valuable metals.
High energy, better safety
So, how does PFTNA technology provide this higher sensitivity so crucial for nickel mining, yet ensure much safer working conditions? The answer to both questions lies in the neutrons. Unlike traditional radioactive isotopes found in other cross-belt analyzers, PFTNA uses a deuterium-tritium neutron generator that can be switched on and off. This produces much higher-energy neutrons than those generated by radioactive isotopes, but drastically reduces the danger of radiation exposure and injury.
The higher-energy neutrons make the CNA Pentos much more sensitive than its peers, enabling precise control of ores and raw material content. But another stage in production can also benefit from better process control: smelting in the electric arc furnace.
The SLN Eramet site in New Caledonia uses a CNA Pentos instrument to control the basicity of the final slag. When basicity was increased from 0.58 to 0.61, and the FeO content from 5.0 to 12.5 wt%, viscosity decreased and the required smelting temperature dropped by 86°C – saving the plant a lot of energy over time! Malvern Panalytical has supplied several CNA Pentos analyzers to sites in New Caledonia, including one to Glencore.
Immediate action for a better future
In applications from the mine and stockpile to the kiln feed and electric arc furnace, better on-line process control can enable huge savings in energy use, waste, and costs. Not only can efficiency be maximized easily, but processes are made more sustainable thanks to the compounding effects of lower energy use and efficiency gains that add up rapidly.
The mining industry today does not have the luxury of waiting until it’s completely ready to transform itself for a more sustainable future. The world needs metals now, and sustainability is an urgent priority. Fortunately, solutions like better on-line analysis are an easy and truly impactful step that can be taken immediately, resolving the dilemma of higher production bringing higher environmental impact.
To discover how Malvern Panalytical’s CNA Pentos and other solutions can get your mining processes future-ready, contact us today! Our experts are always ready to give advice on the best approach for your application.
