How Metso Analyzers enable process monitoring and control for battery metals production

Courier® HX analyzer system

The Metso Courier® HX is a high-performance solution analysis system that can measure up to 24 samples automatically. Samples can be analyzed from aqueous and organic solutions without any cross contamination of samples occurring. Depending on the analysis needs, the analyzer system can be equipped with various elemental/chemical analyzers, including X-Ray Fluorescence (XRF), titration, ion chromatography (IC) and optical emission spectroscopy. Samples containing solids can be automatically filtered to enable analysis of the liquid phase.

The heart of the analyzer system is usually a Courier® 6X HX XRF analyzer (Figure 2), which offers a rapid measurement of samples, typically taking 1-5 minutes per sample. Depending on the sample, the analyzer can utilize Wavelength Dispersive (WD) or Energy Dispersive (ED) spectrometers. The WD spectrometers are especially preferred if a sample contains Ni, Fe and Co, as ED spectrometers usually struggle to detect the Co signal from neighboring Ni and Fe fluorescence signals (see Figure 3).

The XRF analyzer has the ability to work with a wide range of measurements, as samples with concentrations from 1-10 mg/L to 100 g/L can be analyzed using the same system - without the need for dilution of samples. For example, in Ni and Co separation by solvent extraction, trace quantities of Co can be detected in high Ni concentration solutions and vice versa.

One analyzer system analyzing 12 samples from the process (if a 5 minute per sample cycle is being used) can produce more than 100 000 assays automatically during just one year of operation. This significantly increases safety whilst also reducing operating costs, as manual sampling and assaying is greatly reduced.

The analyzer system is not just limited to one analyzer. It can be equipped with three different analyzers which share the same sampling streams with each other. For example, the system can consist of an XRF analyzer which is used to measure metals of Ni, Co, Mn, Fe, Cu, as well as an automatic titrator unit which is used to measure acid in the samples and an optical emission spectroscopy analyzer to measure lighter elements e.g. Li, Na, Mg in the samples (Figure 4).

Ni, Co and Mn chemical production

Cathode materials determine the battery’s performance, safety and cost in Li-ion batteries. Ni, Co and Mn are key elements in battery cathodes, particularly in the popular NMC chemistry. Each of these elements contributes to the properties of the battery, offering balance between energy density, stability and cost.

For battery production, these metals are usually produced as sulfate chemicals e.g. NiSO4·6H2O. The production of these sulfate metals typically involves leaching, impurity removal, solution purification and crystallization steps.

In the leaching phase, elemental analysis of Pregnant Leach Solution (PLS) is an important step for process control and monitoring. The main metal concentration can be used to assess the leaching efficiency. Higher concentrations of target metal and/or impurities may affect the chemical consumption in further processing steps. In addition, lower concentrations can also lead to inefficient processing.

Acid concentration in PLS is also monitored to keep the acid at optimal concentration. High acid may improve leaching efficiency but may also lead to challenges such as high impurities in solution purification and increased reagent consumption. With low acid concentrations, this can reduce the overall extraction efficiency and recovery rates.

Ferrous (Fe 2+) and ferric (Fe 3+) iron content in PLS can be monitored by titration. In many operations, the Fe is oxidized to ferric iron to enable Fe precipitation in lower pH, thus allowing Ni to stay in the solution. The ferrous/ferric ratio in the PLS can be monitored using titration, which enables the optimization of the oxidizing reaction and allows for efficient Fe removal from the PLS.

In solvent extraction (SX), the PLS is concentrated and purified. Pure metal sulfates are produced in the following processing steps. To ensure optimal metal extraction by SX, the target metal can be measured in both aqueous and organic samples.

The SX process is based on the differences in chemical behavior of the target metals in aqueous and organic phases to selectively separate them from leach solutions. Continuous measurement of both phases enables the monitoring/optimization of the distribution coefficient of the SX process. By implementing online analysis, this significantly improves both stability and performance of the process.

In the organic washing phase, it is important that the impurity metals are efficiently removed before the stripping phase in order to prevent contamination of the final product. By measuring the organic wash stream, impurity carry over e.g. Fe, Cu from PLS can be monitored.

In the stripping phase, the target metal in the stripping solution is an important measurement to determine the efficiency of the stripping process and the quality of the final product. Maintaining target metal concentration in the strip solution enables efficient stripping process and optimal recovery from the circuit. The acid concentration in the strip solution is also an important parameter to enable optimal recovery and reagent consumption in the stripping phase.

Precursor cathode active material (pCAM) production

Prior to production of battery cathodes, the metals sulfates are converted to precursor cathode active material (pCAM). Typically, the sulfates are converted into metal hydroxides in the pCAM process. According to the need of the end customer, common product from the pCAM process is NMC 811 (8 parts nickel, 1 part manganese and 1 part cobalt) mixed metal hydroxide. Other pCAM products include NMC 111, NMC 955 and NCA (nickel cobalt aluminium).

The pCAM process starts by dissolving the target metal sulfates in water and mixing the sulfate solutions to the target chemical concentration e.g. NMC 811. The metals are then precipitated out from the solution as a mixed metal hydroxide product Me(OH)₂. Metso’s Courier HX analyzer system can then be utilized to maintain the target metal concentrations in the sulfate solution and to monitor any metal losses in the effluent streams.

One of the most critical parameters for the battery cathode quality is the particle size and tap density of the Me(OH)₂ product. Optimal particle size depends on a variety of aspects, such as specific battery chemistry, desired performance and intended application.

To address this, Metso’s novel PSI® 1000 particle size analyzer has been designed to analyze the particle size and distribution of the pCAM products in real time. Using real time particle size measurement allows for better control of the intended particle size distribution and span whilst also minimizing off-spec product.

The PSI 1000 particle size analyzer is based on laser diffraction, which is widely used as a reference method in laboratory for pCAM processing. The analyzer can provide the full particle size distribution of the sample starting from 0.1µm. Having accurate and real time detection of an off-spec product has a range of benefits for operations, such as significant savings due to less waste of the starting material. In addition, PSI 1000® gives information when the end-product specification is reached thus enabling starting the next batch as early as possible, effectively maximizing reactor utilization and capacity of the whole plant.

Battery black mass recycling process

Black mass recycling process treats batteries after mechanical separation through hydrometallurgy. Valuable metals such as Cu, Mn, Co, Ni and Li are recovered from the used batteries. This method significantly reduces the carbon footprint of the battery supply chain. In addition, the recovered materials can be used in the production of pCAM product for new batteries, thus contributing to a circular economy.

Black mass process involves leaching of the black mass, followed by precipitation to recover copper and remove impurities such as Fe and Al. The solution is then treated using solvent extraction to systematically recover the remaining metals one by one. Similar to hydrometallurgical processing of primary metal production, the Courier HX analyzer can also be applied to the black mass recycling process.

Explore in this blog how Metso, a frontrunner in circular economy, addresses the battery boom with our sustainable battery black mass recycling process.

Greater efficiency, quality and sustainability

Utilizing Metso’s advanced analyzer solutions, such as the Courier® HX system, PSI® 1000 particle size analyzer, pCAM plant and more, play a critical role in optimizing the production and recycling of battery metals. By offering real-time, high-precision measurements, these analyzers enable continuous monitoring and control throughout key process stages, including chemical production and black mass battery recycling.

This not only ensures the efficiency and quality of the end product, but also contributes to sustainability through the recovery of valuable metals. As the battery industry continues to evolve, Metso’s innovative solutions further enable operations to meet increasing demand whilst improving both their performance and environmental impact. That’s why, together, we are the partner for positive change.