The gold plant of the future

Kenneth deGraaf paints a picture of highly sophisticated gold plants that can provide improved sampling and ESG outcomes, thereby helping to meet the ongoing demand for gold that is processed safely, efficiently and sustainably.

Why is now the right time to be talking about harnessing technology to get the most out of gold processing plants?
Kenneth deGraaf (KD): Gold processing plants are operating in an increasingly challenging environment with regards to energy, labour and environmental, social and governance (ESG) considerations. We are also seeing average grades of new deposits continuing to decline.

Optimising operations over a range of sometimes competing objectives requires the best available technology and trained personnel to operate and maintain plants. None of this has a simple answer, and the challenges are often site-specific. But harnessing the most advanced yet acceptable technology should always be a component of getting the most out of any mineral processing plant.

In your presentation at Gold Plant, you talked about the importance of correct sampling practice – can you please explain why this is critical for plant operators to get right? What sort of value can proper sampling provide?
KD: In a gold processing plant, if you don’t have accurate information on how much gold is entering and leaving the plant through various process streams then you will not know whether your plant is operating efficiently or if it is optimised.

What’s more, it is not enough to know how efficiently the plant is recovering the gold product – it is often important to know what deleterious elements the plant may also be processing and releasing into the tailings. It can also be very important for the tailings management team to know if desliming of tailings is meeting particle size specifications for the tailings storage facility. All of these require accurate sample collection and analyses.

How can laboratory automation improve plant optimisation and productivity?
KD: It is often overlooked that the largest errors in analysing any process stream containing solids (dry or slurry) occur in the initial collection of a sample and the subsequent sample preparation steps (crushing/splitting/pulverizing), not the actual analysis of the sample (fire assay or ICP analysis).

Properly selected and installed automated sampling systems that adhere to the Theory of Sampling are imperatives for unbiased accurate sample collection; it is physically impossible for a human to consistently collect unbiased samples from the usually large process flow streams in modern gold processing plants.

Once the samples are collected, consistent proper sample preparation is essential for maintaining the representativeness of any sample collected from a process stream. Automated sample collection and automated sample preparation laboratories deliver consistently more reliable samples and dependable sample preparation, which in turn provides reliable data for assessing plant performance and optimisation strategies.

Can you provide a real world example/case study of such a laboratory?

KD: FLSmidth has been involved in more than 90 per cent of the global robotic mining laboratories representing over 250 installations, so there are multiple examples/case studies to show the benefits of automated sampling and laboratories. Automated laboratories have been shown to reduce operational costs, enhance quality of analyses, deliver quicker turnaround of analytical results, and also deliver benefits regarding ergonomics, health and safety for plant personnel.

How do resource professionals fit into automated plants – what skills do they need and how will they continue to help deliver business improvements?
KD: For metallurgists and plant engineers, an automated plant would allow for more sophisticated and prompt analyses of operational parameters and the optimisation of process parameters and production. These would likely lead to improved recoveries, reduced reagent consumption/wastage, and lower energy and water consumption.

How might the resource plant of the future improve overall ESG outcomes?
KD: The resource plant of the future should improve overall ESG outcomes by reducing water wastage, reducing energy consumption and reducing emissions – both from fossil fuel usage and from reduced reagent usage. FLSmidth has its ‘Mission Zero’ initiative with the goal to deliver solutions in mining processes to manage zero-emissions by 2030. It’s an ambitious goal that we have proudly committed to that requires a paradigm shift in collaboration, innovation and adoption of new technologies in the mining industry.

Written by: Kenneth deGraaf, FLSmidth’s Global Product Line Manager. Originally published by: AusIMM Bulletin. Posted in: FLSmidth (www.flsmidth.com)

Cementing a great relationship: How X-ray fluorescence and X-ray diffraction go hand-in-hand in cement production

If you’ve ever baked a cake (or watched a baking show), you’ll know how important it is to use the right ingredients in the right quantities. Otherwise, your cake won’t taste very good – and it might not even look like a cake at all! (We’ve all been there.) But imagine if you were describing a list of baking ingredients to a robot, and said ‘sugar’. The robot might choose raw sugar cane, sugar syrup, or sugar lumps. They’re all sugar, after all – just in different forms!

So, the form or state of the ingredients is equally important information to know as what they’re made of. This is quite obvious when you’re working with delicious cake, but it becomes much trickier when you’re working at the microscopic level with individual elements.

Balancing the elements with XRF

In cement manufacturing, the final properties of the cement are affected by its chemical composition. The raw materials are limestone (the calcareous raw component containing CaO – typically around 85%), shale or clay (the argileous component containing SiO2, Al2O3 and Fe2O3 – around 13%), and additives (SiO2, Al2O3 and Fe2O3 at <1% each), which are crushed into powder and mixed to form raw mix. At this point, it’s vital to monitor exactly how much of each material is in the raw mix to keep the correct balance – and this careful monitoring continues throughout the production process using X-ray fluorescence, or XRF.

In fact, there is a whole array of oxides and elements to keep track of. For example, MgO should not exceed 4-5% to avoid cement expansion, alkalis (K, Na) can affect both kiln operation (build-ups) and product quality, and sulphurs can create setting issues and build-ups when present in excess (limited gypsum additions). The typical ratio of alkali to sulphur needs to be kept between 0.8-1.2 (molar). Finally, chloride content must be less than 0.02% to avoid serious build-up problems. XRF analysis is the best way to monitor all these various components, and has been used for process control in cement manufacturing for many years.

This mixture is fired in a furnace, where the heat causes the calcium carbonate of the limestone to decompose into calcium oxide. This part of the process releases carbon dioxide (CO2) along with other by-products – another good reason to ensure all the ratios are precise, as minimizing CO2 emissions is important both to reduce environmental impact and to comply with regulations. It’s also important to control the potentially hazardous elements in alternative fuels, which are increasingly being used to heat the kiln using recycled waste materials. These can cause other emissions that also have a negative impact on the environment.

Completing the picture with XRD

But while all this elemental composition data is invaluable, more information is needed. In our cake analogy, we know we need sugar, but we don’t yet know which form it should be in. That’s where X-ray diffraction (XRD) comes in.

XRD has been traditionally used to catch any instances of early hydration in the final cement product, but it can also be used for process control. Today, XRD is being used more and more often to control the mineralogy of cement clinker, as it identifies the crystalline phase of each component at key stages such as CaCO3, CaSO4, CaSO4.1/2H2O, CaSO4.2H2O, quartz, free lime, free magnesia (periclase), clinker phases and other mineral phases in conventional and alternative raw materials. The Rietveld method allows a complete quantitative picture of the crystal phases in cement, including polymorphs of alite and belite, along with free lime, calcite and calcium sulphates.

This is the key information that was missing before, giving deeper insight into the product as a whole and allowing a more holistic monitoring and control process. Increasingly, data from XRF and XRD are combined into a single report throughout the production process of cement and concrete, providing a well-rounded overview of both elemental composition, crystalline phase, and quality.

By combining XRF and XRD, it’s much easier for manufacturers to control the quality and final properties of their cement and concrete from an earlier stage in the process. This reduces waste, as any anomalies are picked up earlier, as well as making kilns more efficient and saving energy and CO2 emissions.

Smart systems for future-proof processes

A highly accurate XRF spectrometer like Malvern Panalytical’s Zetium pairs well with a compact and robust XRD instrument, such as the Aeris. The benefit of using these together is that they both support automation using the Universal Automation Interface, and Malvern Panalytical offers support and guidance from initial setup to advice on sample preparation and technical assistance. Our instruments are suitable for use from a busy production environment to a laboratory, and can also be integrated into laboratory information management systems (LIMS).

Written by: Murielle Goubard, Posted by: Malvern Panalytical (www.materails-talks.com)

Digging into rare earth elements: Mineralogical analysis with XRD

Contrary to what their name suggests, the 17 rare earth elements (REE) are not all that rare. In fact, they can be found in many minerals, and are often helpfully gathered together – but they occur in such small concentrations that they’re hard to isolate. So why go to the effort of trying to extract them?

To answer that, we need to understand why worldwide demand for REE has boomed in recent years (according to the US Geological Survey, REE mine production more than doubled between 2017 and 2021, to around 280,000 metric tons). Quite simply, it’s because REE are essential for the technologies that underpin today’s (and tomorrow’s) society. The elements that make up this group are used in everything from the everyday to the futuristic, in industries as diverse as electric mobility, wind power, consumer electronics, and defense technologies.

Facing up to the challenge

With demand for REE in applications like catalysts, screens, and magnets on the rise – and recycling rates remaining very low – getting hold of these valuable elements efficiently is becoming increasingly critical. Locating deposits for the most in-demand minerals can be a challenge all of its own, but even after sourcing, rare earth exploration and deposit mining need more frequent, more accurate monitoring solutions to ensure optimal characterization and processing. In turn, this can reduce the costs of reagents and improve the yield from the raw ore feed.

Twice as nice: Combine our XRD and XRF solutions

Malvern Panalytical’s Aeris Minerals edition provides the mineralogical insights mine operators are looking for. Using the power of X-ray diffraction (XRD), it enables operators to understand the qualitative and qualitative composition of complex REE-bearing minerals, including bastnäsite, synchesite, monazite, xenotime, florencite, eudialyte, catapleiite, aeschynite, and samarskite. With this intuitive compact machine, users can rely on high sample throughput with rapid analysis and maximum uptime. 

Better still, the Aeris is perfectly complemented by the Minerals edition of our Zetium X-ray fluorescence (XRF) spectrometer, the ideal solution for elemental analysis of geological materials. The Zetium Minerals edition has been designed to deliver superior analytical performance and stability, even in demanding mining environments. 

Together, the Aeris and Zetium Minerals editions support speedy, informed decision-making – giving your REE operations the edge and helping you mine those rarest of elements: time and cost efficiencies!

Written by: Uwe Konig, Posted by: Malvern Panalytical (www.materials-talks.com)

Why iron ore pellets are good news for sustainable steel

What does your kitchen sink have in common with the Burj Khalifa skyscraper in Dubai? They might be on a slightly different scale, but they’re both made of steel – the metal that supports our society. Without the steel industry, our world would look very different. But as economies around the world turn toward sustainability with increasing urgency, the steel industry is faced with the challenge of keeping pace. 

Supporting society in a new way

Achieving carbon neutrality by 2050 – the ambitious target set by many governments – won’t be easy for any of us, but the steel industry is facing one of the biggest challenges of all. Partly, this is due to its size: during 2020, about 1,864 million metric tons of crude steel were produced. At this scale, serious environmental impact is guaranteed using traditional production methods. The sintering phase is particularly well-known as the most energy-intensive and polluting step in the entire process. Society needs the industry’s support in a new way today: through rapid change. 

However, the huge scale of the steel industry could prove to be its biggest asset in the race to sustainability. Working at scale means that small changes have big effects – it’s the reason that process efficiency is so important. Each improvement has a big impact, which makes each step very meaningful. 

The sinter solution

Manufacturers have already begun to focus on sinter as the focus to start cutting emissions, and pelletized iron ore offers an innovative solution. Pellets reduce the amount of coking coal required and improve furnace productivity, reducing CO2 emissions in the process. By replacing sinter with high-grade pellets, traditional sintering can be skipped entirely – with electric arc furnaces (EAF) taking the place of the blast furnace, and direct-reduced iron (DRI) as an alternative feed material to steel scrap. This method is known as DRI-fed EAF, and it’s widely considered one of the best ways for the industry to reduce emissions. 

DRI-fed EAF offers a practical and hopeful solution to manufacturers at a time of pressure, which is why many have already made the switch. But process control is just as important in this more sustainable method as in the past, as manufacturers need to keep quality high and their furnaces running as efficiently as possible.  

Preparing for Industry 4.0

Process control in metal production relies heavily on analysis, and precision is key. To reduce waste, keep costs low and ensure quality, manufacturers need to understand every property of their materials, from their mineralogical phase and crystalline structure to particle size. This has always been the case when working with sinter, and it applies to iron ore pellets too. Any efficiencies gained can be lost again if materials are ‘off-spec’.

Tools such as X-ray diffraction (XRD), X-ray fluorescence (XRF) and laser diffraction analysis are already widely used and will only become more important in the transition to carbon-neutrality. But the days of laboratory testing and unrepresentative sampling are over – at least, in optimized production environments. Often called ‘industry 4.0’, automated solutions and high-throughput analysis are presenting manufacturers with another valuable way to maximize their efficiency and reduce their environmental impact.  

Futureproof tools

Instruments like the AerisAxios FAST and Insitec ranges from Malvern Panalytical are helping metals companies keep up in the sustainability race and future-proof their processes. With automation options and high-throughput capacity, they offer expert analysis at the speed the modern industry demands – saving time, resources, and costs. In a rapidly evolving steel landscape, better analysis is a trustworthy guide. 

We’re proud to be helping make the transition to automation and sustainable practices smoother and easier.  

Written by: Uwe Konig, Posted by: Malvern Panalytical (www.materials-talks.com)

Discover how an X-ray diffractometer can automate thin film metrology processes – Q&A

If you would like cleaner, quicker, and more efficient wafer analysis with your X’Pert³ MRD XL X-ray diffractometer for thin film metrology, our recently launched MRD XL Automation tool might just the answer you are looking for. By communicating closely with the host computer with the widely used SECS/GEM protocols, this MRD XL can be automatically controlled, adapted, and efficiently managed throughout the research or production process – from initial wafer selection to results distribution – to meet all your needs.

To engage with our partners and provide insights into how to effectively automate your thin film metrology processes, we recently hosted a live webinar. If you missed it – no worries. You can find the recording here. We’d also like to share some of the most relevant questions we received, as well as our answers…

In the analysis automation can limits be set where any values outside a certain range are flagged with the area on wafer highlighted but do not stop the process?

There are several routes imaginable to achieve this. Firstly, in the host. Secondly, in an analysis script on the local PC. To provide a precise answer, we would need more case-specific information, but there are definitely opportunities for outputting the requested information.

Can I treat reciprocal space mappings in an automated fashion and process the results?

Yes, AMASS (our analysis package) enables complex peak finding and labeling processes and has extensive options regarding its automation via its language-agnostic interface.

Where do you keep measurement data?

By default, the data is stored on a local PC but storage on a file server is also possible. As scripting is part of the solution the opportunities to do this is virtually unlimited.

What’s the maximum and minimum scan areas? And what are the max number of spots on wafer that you can set for automation?

A 200mm wafer can be fully mapped. A 300mm wafer can be handled by automation, but only partially mapped. We have experience with 3-digit numbers of spots for measurements and see no reason for a limit that will be reached in practice.

Written by: Tom Gorter, Posted by: Malvern Panalytical (www.materials-talk.com)

How lower energy use is becoming more accessible in mining

How did you get to work today? Whether it was in an electric car or on a train powered by renewable electricity, the energy transition is already happening all around us. But reshaping the infrastructure of our homes, workplaces, and industries to become more sustainable will take a lot of work – and a lot of metal.

Powering the energy transition…

It’s projected that up to three billion tons of metal will be needed to support the net-zero targets adopted by many countries and industries. Good news for metals prices – but also a dilemma, as the industry takes on sustainability challenges of its own and seeks to reduce its environmental impact.

Accounting for around 3.5-4% of the world’s energy use, the mining industry is a significant player in worldwide consumption. Many mining processes are inherently energy-intensive, and more sustainable alternatives are not yet available. With many companies having made sustainability commitments ahead of 2030, time is short.

…while decreasing our energy consumption

Accurate elemental analysis provides a flexible, immediate solution to this challenge. Better elemental analysis can be applied from the stockpile to the blast furnace to unlock significant process efficiencies. As the demand for metals continues to spike – those three billion tons will be needed soon! – inefficiencies that might have gone unnoticed before will make themselves felt, but the ability to sort ores easily and in real time can transform the entire metals value chain.

Sorting ores allows the direct detection of any variations or anomalies in ore composition, which makes stockpile management much more efficient. Controlling washing and preventing the processing of waste material saves significant time and energy, and ensures higher consistent quality.

Having ores sorted from the beginning of the process also makes later stages run more smoothly, compounding the benefits downstream. A more consistent output means that fewer additives or corrections will be needed, and eventually can enable more efficient running of the blast furnace – the most visible point of energy consumption.

What do we mean by ‘better’ analysis?

The most immediate way to make analysis more efficient is to get results in real time. Cross-belt analyzers eliminate the need for sampling, saving both time and costs. Analyzing all the material on the belt – from large rocks to fines – means that results will always be representative, and any adjustments needed can be made instantly rather than after testing is carried out elsewhere. The CNA cross-belt analyzers from Malvern Panalytical are designed to accommodate a wide range of belt sizes, making them suitable for many different applications.

At the smaller scale, the CNA instruments make use of pulsed fast thermal neutron activation (PFTNA) technology, using a pulsed flow of neutrons to interact with the nuclei of the atoms in the passing material. The atoms emit gamma rays, and the instrument measures the characteristic energy levels of these rays to identify and quantify the elemental composition of the material.

CNA instrument in the Nickel mining plant

Highly accurate, this method is also very safe for operators. The neutron-emitting module can be switched off during downtime or for maintenance, minimizing their exposure to radiation, and saving precious time on administration and compliance procedures to comply with safety regulations. There’s also no hazardous waste, making PFTNA significantly more sustainable in the long term.

 

Can this be applied across the industry?

PFTNA technology can be applied across a wide range of mining and metals applications, including in the processing of iron ore, bauxite, coal, copper, nickel, and limestone. The CNA analyzers from Malvern Panalytical come in a variety of industry-specific formats, with designs tailored to the specific ore to ensure the greatest efficiency gains possible. They’re flexible in calibration and particle size, depending on the application, and their robust design keeps the cost of ownership and maintenance low.

So, the dilemma of supporting the energy transition while lowering energy use doesn’t have to be a dilemma at all – it can be an opportunity! Thanks to technological innovations like PFTNA, mining and metals can find a way forward that swaps challenges for benefits.

 

Written by: Uwe Konig, Posted by: Malvern Panalytical (www.materils-talks.com)

Turning Alumina into Aluminum

Continuing our series on the aluminum industry,  this blog will look into how powdered aluminum oxide, also known as alumina or Al2O3, is turned into solid aluminum metal.

Aluminum is found in many places in everyday life, from beverage cans to airplane parts, automobile components, power lines and even cooking utensils. It has become an indispensable part of the infrastructure of our lives, which is why we are looking to expand our portfolio to offer a wider variety of Al materials to our customers.

To review, alumina starts as bauxite that is mined from the ground and then heated with various chemicals and purified to alumina. The yield from bauxite to Al2O3 is roughly 2:1. This powdered Al2O3 is further purified to aluminum, with another yield of roughly 2:1, so each pound of aluminum metal starts with 4 pounds of bauxite.

The Hall-Heroult process is utilized to transform the powdered Al2O3 into Al metal. This process uses a carbon-lined steel vat to hold the alumina and cryolite (Na3AlF6), while carbon electrode rods are then placed above the vat. The vat is heated to just under 1000°C which melts the cryolite, and the molten cryolite is then able to dissolve the alumina. Finally, an electric current is set up between the carbon vat lining and the upper electrodes causing the Al2O3 to break apart, and the molten Al to collect at the bottom of the vat. The Al metal collected at this stage is typically 99.8% pure and will require further processing to be used for the various Al Alloys we use in society today.

Aluminum Blog

Every stage of the entire process requires quality control, the incoming bauxite is screened for compositional analysis. The red mud by-product is screened for environmental compliance with the effluent. The alumina powder is screened for purity, and to ensure that the process is complete. The smelting process has a series of checkpoints. The incoming alumina and cryolite are screened for purity, as is the final metal. Even the steel vat, the carbon lining of the vat, and the electrodes above will have been checked at some point in their life cycle.

At the end of their life cycle, hopefully all of these materials will be recycled, which introduces a whole new set of checkpoints. All of these checkpoints are opportunities for reference materials to be used. Powdered geological materials, liquid ICP standards, and metal standards all have their place in the cycle. LGC Industrial offers many of these materials already, and we are currently developing our own line of powdered geological materials which will be released in the coming year.  Until then, browse our one of our existing product catalogs to find the reference materials you require.

Written by Kim Halkiotis, Posted by: ARMI MBH (www.armi.com)

X-ray diffraction: The next step in copper’s 9,500-year-old story

Can you guess how long humans have been mining copper? Sites in North America indicate that ancient peoples were using copper as long as 9,500 years ago! They used it to create tools, weapons, and jewelry. In our own times, this metal has come to be prized for another reason: its conductivity.

Copper: Why we can’t get enough

Around the world, economies and industries are striving for sustainability – and technology is evolving alongside them. In particular, there’s rapid innovation in the technologies that power renewable energy and electric transportation. New developments in these industries have a huge potential to change how we live, get around and do business.

One thing that those new technologies tend to have in common is that they use a lot of copper. This is because of its amazing conductive properties – it’s a highly efficient material. Less energy needed to produce electricity means less CO2 emitted, for example. As electric vehicles and renewable energy scale up around the world, the demand for this red metal is hitting record highs. The world has changed a lot in 9,500 years!

New challenges need new solutions

The mining industry is turning to lower-grade ore to meet demand, as high-grade ore is becoming harder to find. However, this comes with some complications: the lower the grade, the more difficult it is to recover the valuable metal and the more impurities it has. Producers need to get the most out of their ores, so they invest increasing amounts of energy and resources into the recovery process. Over time it’s becoming less sustainable – and less profitable too.

But what might seem like a problem is really an opportunity. Any efficiency improvements to this process will have a huge impact on sustainability and profitability. The answer? Better analysis!

X-ray diffraction analysis transforms production

After copper ore has been finely ground into powder, it’s often blended before being separated into valuable metal and gangue (waste) through the flotation process. Rapid, precise process control is key at this stage to avoid inefficiency and unnecessary costs.

Fortunately, there’s no need for guesswork. X-ray diffraction analysis (XRD) is ideally suited to characterizing the mineralogical composition of materials – it detects and quantifies the minerals present at even minor concentrations.

PN10700 172 Feature

A 2021 study by Pernechele et al. published in Minerals found that XRD analysis using our automatable Aeris instrument was fast and accurate at determining the mineralogy of copper ore blends, tailing (leftover material), and concentrates.

XRD reveals mineral composition, crystalline structure and texture, and can even directly predict process parameters. Armed with this rich, accurate data, manufacturers can optimize their resources and save energy – transforming the entire production chain. And with less waste and lower energy use, the environmental impact is reduced too!

Get started with Malvern Panalytical

Analysis is the key to bringing traditional materials into the sustainable future. Malvern Panalytical’s range of XRD instruments combines expert-level data with push-button ease of use and flexibility. With specialized editions for the industries that benefit most, we offer a solution for every need – and automation options ensure your processes are as efficient as possible. So, get in touch and find out how we can help optimize your set-up today! You can also take a look at all our base metal mining solutions here.

 

Written by: Uwe König,, Posted by: Malvern Panalyitcal (www.materils-talks.com)

How to improve paint and coating formulations: Crystal phase analysis

In this series of five blog posts, we’re examining the analytical approaches that you can use to get a better understanding of paints and coatings at a nanostructural level. Number two is an approach that I think no coatings scientist can do without – crystal phase analysis using X-ray diffraction.

Since their discovery by Röntgen in 1895, X-rays have found many uses in physics, chemistry and materials science. In fact, I’ve already covered the use of X-ray fluorescence (XRF) to determine elemental composition in my previous blog post. But despite being based on the same process of hitting a sample with X-rays, XRF’s analytical cousin X-ray diffraction (XRD) works in a rather different way and provides completely different information.

Using XRD for crystal phase analysis

XRD operates on the principle of irradiating a crystalline material with monochromatic X-rays and then measuring the angular intensities of the same wavelength X-rays as they scatter from the material. In contrast to X-ray fluorescence for elemental analysis, (in which the individual elements in a material respond with a characteristic X-ray spectrum), in XRD, X-rays are scattered by the regular arrangement of molecules in crystalline lattices. In large enough crystals, the scattered waves interfere to produce a diffraction pattern.

Diffraction patterns give information about both the molecules in a material and the crystal structure they have in solid form – a combination called a ‘phase’. For larger crystals the diffraction patterns are strong and can tell you lots about the internal structure of the crystals, whereas for smaller crystals (such as nanocrystals) the interference is weak, and instead only a scattering pattern is analyzed. Nevertheless, a scattering pattern can still give you information about the size and shape of nanocrystals and nano-layers.
In days gone by, you’d have had to interpret these scattering and diffraction patterns manually, which required more maths than most people would be comfortable with, but the good news now is that all the analysis is automated.

This means that you queue your sample for automated acquisition and data analysis, and find out a large amount of information about your sample – including the materials present, the distribution of phases, the characteristics of crystallites, thin films and nanoparticles, as well as details of strain, preferred orientation, layer thickness, and much more.

In terms of the amount of information that can be gained using a single technique, that’s pretty impressive. But what is XRD actually useful for in the field of paints and coatings?

What is XRD used for in the paint industry?

Checking chemical purity

You’ll hardly need me to tell you that the performance of paints and coatings depends crucially on the quality of the components that go into the formulation. So it’s little wonder that one of the most widespread uses of XRD in the paints and coatings industry is to check the purity of incoming material.

Top of the list for inspection is titanium dioxide or TiO2, which is used as a pigment in many coatings because of its opacity and white color. However, it comes in two polymorphs, anatase and rutile, with the latter being preferred because of its higher refractive index. Fortunately, determining the ratio of these two is an easy task for XRD, allowing manufacturers to make sure that their supplies don’t deviate from what’s needed (the use of XRD for this task is even the subject of a standard method, ASTM D3720).

Fine-tuning color performance

In addition to simply checking supplies, XRD has a role to play in more advanced formulation science, by looking more closely at the color performance of a particular component.

For example, the various phases of iron oxide used in formulations provide gradations of color that are important for achieving the right balance of tinting strength and hue. Built upon many years or artistic endeavor, there are plenty of other pigments where understanding the exact nature and purity of an inorganic or organic compound – or mixtures of them – is critical to achieving a reproducible and enduring color specification.

There is also a large new world of extenders, which can be mineral or organic particles that are more cost-effective than the main color pigments and which can contribute positively to the final color performance. But their mineral purity is important, and phase analysis is frequently used to identify and screen any mineral inconsistencies.

(By the way, color will be a big focus of the next blog post in this series, when we’ll be talking about the effect of particle size and shape).

Investigating smart coatings

Last but certainly not least in this short review of the applications of XRD are so-called ‘smart’ coatings. These are coatings that respond in some way to an external influence – such as varying their refractive index in response to temperature or electric field. In many of them the ‘smart’ function is contained within crystalline pigment particles, which require the same analytical considerations as mentioned above for ‘color’ pigments.

But whatever exciting properties they may have, smart coatings are still fundamentally coatings, and so can be investigated using the same techniques. Once again, XRD is of particular value, because it is unsurpassed in its ability to provide nano-scale information on surfaces and polycrystalline thin films. For example, XRD experiments dedicated to surface thin films can tell you about residual stresses, preferred orientation, film thickness and other aspects of surface microstructure – all of which are essential in order to know how your final coating is performing and whether it’s going to remain ‘smart’.

Anti-reflective glass with an optical interference coating

XRD – In-depth crystal phase analysis

All the above examples show the growing importance of XRD in the world of paint formulation and application. This is especially true given the growing pressure on quality of supplies, and as the accelerating need for higher-performing coatings piles pressure on manufacturers to understand what’s happening in coatings at the nanoscale.

In conclusion, as someone who’s spent much of my career using XRD, it might come as no surprise to hear me say this – but if you allowed me just one analytical technique to use in the paints and coatings sector, it would have to be XRD!

 

Written by: Patricia Kidd, Posted by: Matvern Panalytical (www.materials-talks.com)

How is Alumina Produced?

Alumina is the common name for the chemical compound aluminum oxide (Al2O3). Naturally occurring Al2O3 is called corundum, and it is the foundational component of both rubies and sapphires (color variations arise from the impurities that are found in the crystals). Alumina for industrial use is refined from bauxite ore, which is a mixture of the hydrated aluminum oxide minerals; gibbsite, diaspore, and boehmite along with other compounds such as silicon dioxide, iron oxides, and titanium oxide. Bauxite is often mined from topsoil in tropical and sub-tropical regions. The Bauxite is then treated using the Bayer Process, which separates the bauxite into red mud and Al2O3 using a combination of heat/pressure and sodium hydroxide. Aluminum hydroxide, in the form of fine-grained crystals, is added to facilitate precipitation of aluminum hydroxide crystals. The hydroxide mixture is then heated to drive off the water, producing several grades of alumina; calcined alumina, smelter grade alumina and activated alumina.

Alumina_webimage2

The purified aluminum oxide has many uses, with perhaps the best-known being the end-use in foundries which turn it into aluminum metal, which in–turn is used in a variety of applications. The powdered alumina is also used in several industries, including as fillers in plastic, an abrasive in grinding applications, ceramics, and even to produce reflective effects in metallic paints for automobiles! One of the largest industrial applications for Al2O3 is as a catalyst in refineries, to convert hydrogen sulfide waste gases into elemental sulfur.

As a reference material producer, LGC understands how critical quality-checks are within each stage of the production process. Screening is needed from the raw bauxite coming out of the ground, to the red mud by-products, as well as purity screening of the refined alumina. Once the alumina is turned into solid aluminum metal and Al alloys (to be discussed in a future blog), even more checkpoints are added to the process. LGC Industrial currently provides numerous 17034 aluminum metal standards typically used with either spark OES or XRF, and we will soon be releasing our own line of powdered bauxite and alumina standards.

View our range of aluminum alloy and other metal reference materials by downloading our catalog.  Download Metals Catalog

 

Written by: Kim Halkioti, Posted by: LGC Industial (www.armi.com)