Highlights

• Professor Binnemans identifies systemic waste in precursor cathode active material (pCAM) production, specifically sodium sulfate generated during NMC battery manufacturing.
• Current industrial processes create an imbalance of chemical inputs, with surplus diluted sulfuric acid lacking commercial value and challenging to manage.
• A transformative solution involves rethinking pCAM production by using pure metals instead of metal salts, enabling closed-loop chemistry and reducing waste generation.

In a recent LinkedIn post, Professor Koen Binnemans (opens in a new tab), Head of the SOLVOMET Group at KU (opens in a new tab) Leuven, highlighted a critical bottleneck in the push for circular hydrometallurgy in battery materials manufacturing—specifically within Precursor Cathode Active Material (opens in a new tab) (pCAM) production for NMC (nickel-manganese-cobalt) batteries. Binnemans identifies sodium sulfate waste as a systemic byproduct of current industrial practices, underscoring the mismatch between recycling technologies and real-world chemical balance in these facilities.

As Binnemans explains, pCAM plants typically use metal sulfate salts (not pure metals) as inputs. To precipitate metal hydroxides—key intermediates for NMC cathodes—sodium hydroxide and aqueous ammonia are added, leaving behind vast quantities of sodium sulfate waste. While bipolar membrane electrodialysis (BMED) offers a promising salt-splitting solution by converting this waste into sodium hydroxide and sulfuric acid, it introduces a new problem: an oversupply of sulfuric acid with no immediate industrial use.

According to Binnemans, “Traditional pCAM production consumes large quantities of base but very little acid.” This imbalance raises a hard question for manufacturers: What can be done with surplus, diluted, sodium-contaminated sulfuric acid, which lacks commercial value and is difficult to sell or transport? One potential workaround is to co-locate pCAM and hydrometallurgical refineries, allowing the sulfuric acid to be reused in the dissolution of cobalt and nickel concentrates. However, this only works if logistics are optimized and acid purity is strictly controlled—both tall orders in today’s fragmented battery supply chain.

A more transformative solution, Binnemans argues, is to rethink the front end of pCAM production altogether. Instead of using metal salts, manufacturers could start with pure cobalt, nickel, and manganese metals. This would enable direct use of sulfuric acid in metal dissolution, creating a closed-loop chemistry and reducing sodium sulfate generation at the source. A recent patent from Glencore Nikkelverk AS (opens in a new tab) (WO2023187107A1) (opens in a new tab) demonstrates the viability of this approach using a continuous dissolution reactor.

As Western nations and major automakers scramble to build resilient and sustainable battery supply chains, this insight carries urgent implications. The real bottleneck may not be sourcing critical minerals, but designing production systems that don’t generate waste streams they cannot economically or environmentally manage.

Source: Koen Binnemans, LinkedIn post, June 8, 2025

Patent Reference: WO2023187107A1 – “Continuous Dissolution Reactor,” Glencore Nikkelverk AS

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