Precision Hydrometallurgy Moves Battery Recycling Beyond Black Mass

Beyond Black Mass: How Precision Hydrometallurgy Is Defining the Next Generation of Battery Recycling by
Proses Makina

For much of the battery recycling industry, producing black mass has become the visible milestone.

Spent lithium-ion batteries are discharged, shredded, dried and mechanically separated. Copper, aluminium, steel and plastics are removed, leaving behind a fine material rich in lithium, nickel, cobalt, manganese and graphite. But black mass is not the end product of battery recycling.

In many ways, it is where the most technically demanding part begins. The real challenge is converting a chemically complex and increasingly variable black mass into separate, high-purity metal streams that can re-enter industrial supply chains.

At Proses Makina, this is where we believe the next generation of battery recycling technology will be defined: precision hydrometallurgy.

Producing Black Mass Is Only the First Step

Mechanical separation is essential to any efficient recycling plant. Effective shredding, drying, sieving, magnetic separation, air separation and non-ferrous metal separation reduce the amount of copper, aluminum, iron, plastics and other contaminants reaching the chemical section of the plant. Proses Makina designs and manufactures these systems as part of complete battery recycling lines.

However, recovering a black mass fraction is fundamentally different from recovering individual metals from that black mass. Once the material reaches the hydrometallurgical section, physical separation is no longer enough. Nickel, cobalt, manganese and lithium must first be transferred from the solid material into solution through controlled leaching. 

The engineering question then becomes much more difficult:

How do you selectively separate metals that behave very similarly in solution?

Why Nickel and Cobalt Separation Is So Challenging?

Nickel and cobalt provide one of the clearest examples. Both are transition metals with closely related chemical behaviour, and both are present together in many NMC battery cathodes. After leaching, they can coexist in the same pregnant leach solution along with manganese, lithium and residual impurities. Simply dissolving them is not enough. They need to be separated selectively while maintaining high recovery and purity.

This is where solvent extraction, or SX, becomes one of the most critical sections of the recycling plant. In solvent extraction, an aqueous metal-bearing solution is contacted with an organic phase containing a selective extractant. Under carefully controlled chemical conditions, one metal preferentially transfers into the organic phase while another remains in the aqueous solution.

The principle may sound straightforward. Industrial execution is not.

For difficult separations such as cobalt from nickel, selectivity can depend strongly on a narrow operating window. Small changes in pH, organic-to-aqueous ratio, metal concentration, temperature, residence time or mixing conditions can influence extraction behaviour and final product quality.

It has to be operated as a precisely controlled chemical separation system.

pH Is Not Just a Measurement — It Is a Process Variable

In hydrometallurgy, pH directly influences which metal species preferentially interact with the chosen extractant. For this reason, Proses Makina places particular emphasis on continuous pH monitoring and control throughout the solvent extraction circuit.

Rather than measuring pH only at the beginning or end of the process, sensors are positioned across critical process stages so operators and the automation system can follow how conditions evolve through the circuit. This allows chemical dosing to respond to actual process conditions rather than relying solely on fixed dosing rates.

For metal systems with closely spaced extraction behaviour, this level of control becomes particularly important. Precision is therefore not an additional feature of an SX plant. It is part of the separation mechanism itself. 

Proses Makina’s SX systems use mixer-settler stages designed to provide controlled mixing followed by effective phase disengagement. Multiple stages can be arranged according to the required extraction, scrubbing and stripping sequence.

Leaching and Solvent Extraction Must Be Designed Together

Before selective separation can begin, the valuable metals need to be efficiently transferred into solution.

Proses Makina’s chemical leaching systems are designed to process the solid products generated after mechanical treatment and prepare a loaded solution for downstream separation. The exact flowsheet depends on the battery chemistry, composition of the feed, impurities present, required capacity and desired final products. This flexibility is important because the objective of hydrometallurgy should not simply be to maximize extraction of everything.

The objective is to recover the right metal, into the right stream, at the required purity, with an economically viable process. 

From Automation to Intelligent Process Control

This is also where battery recycling is beginning to move beyond conventional plant automation. By collecting continuous process data from sensors throughout the hydrometallurgical circuit, plant operators can identify trends, detect deviations and adjust operating parameters before they significantly affect separation performance.

Proses Makina integrates PLC and SCADA-based monitoring, automatic dosing, remote access and process data logging into its solvent extraction systems. Building on this digital infrastructure, data-driven and AI-assisted automation can provide an additional layer of process intelligence, such systems can evaluate relationships between feed composition, pH behaviour, flow conditions, chemical dosage and extraction performance. 

Feedstock Variability Makes Intelligent Hydrometallurgy Necessary

A battery recycling plant rarely receives a perfectly consistent feed.

This is one of the key reasons Proses Makina approaches battery recycling as a complete process rather than as a catalogue of individual machines.

The mechanical section determines black mass quality. Black mass quality influences leaching. Leaching determines the composition of the solution entering solvent extraction.

Solvent extraction determines the purity and recovery of the final metal streams.

Every stage affects the next one.

More Than an Equipment Supplier

The complete plant requires mechanical, thermal, chemical, environmental and control systems to function as a single process.

Proses Makina provides complete turnkey battery recycling solutions covering mechanical preparation, black mass treatment, chemical leaching, solvent extraction, precipitation, waste-acid treatment and related process systems.

This capability comes from experience beyond battery recycling alone.

Proses Makina develops hydrometallurgical and refining systems for valuable and critical metals and has supplied both complete plants and specialized recovery systems for international projects. Its battery-sector experience includes physical black-mass recovery as well as leaching and solvent extraction equipment supplied for overseas projects.

The Future of Battery Recycling Is Precision

As the battery recycling industry matures, producing black mass alone will not be enough.

Future recycling facilities will need to take chemically variable feedstocks and repeatedly produce consistent, high-purity products. That requires chemistry. But chemistry alone is not enough.

It requires precise measurement, controlled circulation, intelligent chemical dosing, reliable mixer-settler operation, continuous process monitoring, automation and engineering that connects every stage of the plant.

This is the philosophy behind Proses Makina’s approach to battery recycling.

From black mass to individual metal streams, we design the complete process — and control the details that make difficult separations possible.

By Hande Bahar

Hande Bahar is a materials and process engineer working with Proses Makina on hydrometallurgical recycling, battery recycling, process development, and international R&D projects. She holds an M.S. in Materials Science and Engineering from the Georgia Institute of Technology, and a B.S. in Metallurgical and Materials Engineering from Yıldız Technical University. A Fulbright Scholar, Bahar’s experience spans battery materials, hydrometallurgy, process engineering, and industrial-scale technology development, with previous experience in both research and advanced materials manufacturing in the United States and Türkiye.

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