What is light element analysis in mining? How analyzing light elements can help optimize your processes

Energy-dispersive X-ray fluorescence (EDXRF) spectroscopy is a workhorse technology in the mining industry. Rapid EDXRF platforms like our Revontium instrument offer reliable analysis that is compact enough to be placed close to your process line, enabling faster decision-making and responsive process adjustments.

However, many EDXRF instruments have traditionally struggled to resolve light elements with sufficient clarity. This has presented obstacles for mine planning, ore processing, and more – but there is a solution.

In this blog, we’ll outline why light elements are important in mining and how you can bring accurate light element analysis closer to your process line with the new Light Elements Boost configuration for our Revontium instrument.

Key takeaways

• Light elements are not often primary outputs for mining, but they are important to monitor throughout the mining process to ensure economical planning, processing, and waste management.
• Light element analysis with EDXRF has traditionally been challenging because light elements emit low-energy X-rays that are susceptible to absorption or attenuation along the optical path.
• Revontium Light Elements Boost solves these issues by offering enhanced light element sensitivity in a compact footprint that can be placed close to your process line.

What are light elements in mining?

Light elements in mining generally refer to low-atomic-number elements, typically those with an atomic number lower than 18. The most process-critical of these light elements are:

• Sodium (Na)
• Magnesium (Mg)
• Aluminum (Al)
• Silicon (Si)
• Phosphorous (P)
• Sulfur (S)

What is light element analysis used for in mining?

Light element analysis is used to support a variety of mining processes, from identifying gangue materials surrounding a target metal to monitoring waste. In copper mining, for example, it is critical at several stages:

Exploration and mine planning

In copper mining, light elements like aluminum and magnesium are not primary outputs, but they are nonetheless important to include in mining analysis during exploration.

This is primarily because of their effect on ore grade. Higher proportions of silicon and aluminum indicate higher gangue content, which dilutes ore grade and increases the volume of material that needs processing. This, in turn, raises energy and milling costs per ton of recovered copper, affecting the economic viability of the deposit.

Additionally, light element content affects a deposit’s processing needs and maintenance risks. No deposit is uniform, so being able to map different levels of certain light elements across your site can help plan effective process sequencing. For example:

Light element level	What it suggests	Planning implications
High sulfur	Sulfide-dominant ores	• Flotation required
Low or absent sulfur	Oxide-dominant ores	• Hydrometallurgy required
High silicon	Quartz or other silicate gangue minerals	• Risk of significant wear to milling equipment due to hard quartz materials
High aluminum and magnesium	Aluminosilicates (feldspars, clays)	• Can contaminate copper concentrates during flotation • Can physically block tubes and other processing equipment

Processing and beneficiation

Once your mine is built, it is important to reaffirm these early findings repeatedly to ensure you choose the right processing route for your materials. Near-line light element analysis is especially powerful when paired with X-ray diffraction (XRD) technology, such as our Aeris platform.

Where EDXRF indicates what elements are present in your materials, mineralogical analysis with XRD can provide a precise look at their mineral structure, helping you make key process flow decisions like sending:

• Sulfide-dominant ores to flotation and further pyrometallurgy
• Oxide-dominant ores to hydrometallurgical leaching
• Aluminosilicate clay-rich ores for pre-treatment such as clay dispersion to prevent contamination during flotation

Slag analysis

The final area in which light element analysis is critical to copper mining is in slag processing and resale. This is when the concentrate is melted at around 1,200–1,300°C, prompting reactions that remove sulfur and cause iron to combine with silica and separate as slag.

As gangue materials, silicates are a given in slag, but to comply with specifications and regulations for traded copper slag in cement production, construction, and other applications, copper producers must ensure they do not exceed certain compositional thresholds.

For example, traded copper slag is often used as an abrasive blasting media in the construction industry as a replacement for silica sand, which typically contains up to 99% free crystalline silica and can cause silicosis and lung cancer.

By verifying that copper slag outputs contain <1% free silica, copper producers can ensure compliance with regulations around respirable crystalline silica, such as OSHA 29 CFR 1926.1153.

At the same time, copper producers must track the residual copper content of their slag materials to ensure they are not losing value. Mining analysis methods that can rapidly and reliably quantify silicon and other light elements alongside target metals like copper are therefore essential.

What are the challenges of light element analysis in mining?

Despite its importance at many stages of the mining process flow, incorporating near-line light element analysis has traditionally been held back by several significant challenges.

1. Light elements emit very low-energy X-ray signals

XRF works by firing high-energy X-rays at a sample, exciting its atoms into releasing characteristic X-ray emissions. These emissions are unique to each element, enabling an XRF instrument to precisely characterize which ones are present.

Light elements emit lower-energy X-rays than heavier elements, making them harder to detect. These X-rays are therefore highly prone to absorption by the sample matrix, ambient air, or even the window inside the instrument that protects the detector.

2. Instrument design can obscure light element results

This susceptibility to X-ray absorption means that a vacuum or helium path is necessary for light element analysis, as well as ultra-thin detector windows engineered to minimize signal loss, which have historically been difficult to incorporate into compact, near-line instruments.

3. Sample irregularities can occur in the field

XRF penetrates only a short distance into the sample, making surface contamination and oxidation risk factors affecting XRF accuracy, especially in harsh environments like field labs. Grinding and pressing pellets can also introduce irregularities, contamination, or coatings that obscure or absorb light element signals.

4. High-precision instruments often can’t fit close to the line

Floor-standing wavelength-dispersive XRF (WDXRF) systems offer high-resolution light element analysis, but most require a clean-lab environment and infrastructure. This often makes them unsuitable for near-line environments like container labs, and for processing “dirty” samples like slags and waste materials.

The result is that light element analysis is frequently confined to a central lab environment, lengthening your feedback loop and delaying decision-making. But there is another way.

How Revontium Light Elements Boost enables near-line light element analysis in mining

Revontium Light Elements Boost is the new configuration for our Revontium instrument that enables enhanced sensitivity to light elements, helping you bring actionable light element analysis closer to your process line. Here’s how it does it.

1. Eliminates the biggest source of light element photon absorption

Revontium Light Elements Boost is compatible with helium, improving sensitivity to elements between Na and Cl, and achieves an internal vacuum level below 1 mbar, reducing the likelihood of light element photon absorption. This boosts sensitivity by up to 6× compared to conventional benchtop XRF, with 3× faster throughput for light element workflows.

2. Ultra-thin windows for improved accuracy

While the vacuum and helium path minimizes absorption of light element X-rays on their way to the detector, the thin graphene window ensures minimal absorption at the point of detection. 

3. Compatible with fusion sample preparation instruments

To minimize the interference that can be introduced by using crushed or ground samples, you can use Revontium Light Elements Boost with our Claisse FORJ fused-bead sample preparation system. The FORJ offers simplified sample prep with contamination-free heating and homogeneous melt, ensuring a homogeneous sample surface that maximizes the consistency and accuracy of light element detection.

4. Can be placed close to your process line

Revontium delivers all this in the same compact footprint that has made it a staple in many mining container labs. It offers performance on par with 1 kW WDXRF in a system that occupies just 0.4 m².

With a built-in computer and only 400 W total power consumption, it doesn’t require dedicated infrastructure beyond an ordinary electrical connection. The system is also robust, able to withstand a range of temperatures and offering an air lock and dust collection device to minimize liquid spillage and dust.

Plus, Revontium Light Elements Boost maintains Revontium’s strength of analysis for heavy elements, so you can conduct analysis on a range of samples from raw ore to slag, with minimal turnaround time and maximum decision-making reliability.

Bring efficient light element analysis closer to your mining process line

Effective light element analysis can have far-reaching effects on your mining operations – from planning an efficient layout based on your deposit to ensuring you’re not letting valuable materials go to waste in the slag pile.

Revontium Light Elements Boost makes this more accessible than ever, bringing comparable performance to 1kW floor-standing instruments at a 25% lower operating cost, and closer to your process line.

Find out more about Revontium Light Elements Boost and how it could work in your operations.