A recycling revolution for lead-acid batteries

This think piece was written by Dr Athan Fox, Chief Technology & Innovation Officer, Aurelius Technologies, who are one of our members.

 

Lead-Acid Batteries have been indispensable for industrial progress, but at what cost? As the world is looking towards cleaner and greener energy and recycling solutions, we ask: where will the surplus lead go? Is there a better way?

 

The lead-acid battery (LAB) was invented in 1859 – before the mechanical generation of electricity.

Think about that for a moment: LABs have been around for over 150 years. Today, they command the largest market share by battery type: a figure which is expected to reach $95 billion USD by 2026 (Source: Reports and Data, 20 March 2019). This is despite the electrification of vehicles and the emergence of new and alternative battery chemistries.

 

The most successfully recycled commodity product

LABs are referred to as the world’s most successfully recycled commodity product (Source: Battery Council International). In the US, 100% of these batteries are collected and processed. In Europe, the recycling rates are as high as 95%. It is therefore undeniable that lead batteries are the subject of a uniquely successful circular economy.

But isn’t this strange? After all, LAB recycling started in the 19th Century. This was a time when the general public was far less concerned about sustainability, and certainly long before the emergence of the principles of Cleantech and the circular economy.

So how is it that LAB recycling is so successful, even though it was established at a time when recycling was not trendy and widespread?

The answer is simple: lead metal is infinitely recyclable, and the economics work. For these two reasons alone, LABs are remarkably well-recycled. This is despite the fact that the incumbent technology which recycles them, i.e. lead smelting, is known as the world’s most polluting industry (Source: Ballantyne AD, Hallett JP, Riley DJ, Shah N, Payne DJ. 2018: Lead acid battery recycling for the twenty-first century).

Lead batteries are safe, proven and affordable. They are used in the automotive (fuel, electric and hybrid electric), traction (e.g. fork-lift trucks) and uninterruptible power supply (e.g. in cell phone towers) sectors. As the world is migrating towards cleaner and greener technologies, it is crucial to recognise the widespread importance of LABs.

Indeed, these batteries can support tomorrow’s Cleantech industry and our transition to a zero-waste future. But for this to happen, the incumbent LAB recycling industry must become cleaner, more energy-efficient and less wasteful.

 

Aurelius and our innovative technology for the recycling of lead battery paste, the active ingredient in LABs, are here to catalyse this change.

Funded by Horizon 2020 and Innovate UK, our technology starts with separation of the spent materials (i.e. the waste battery paste) from lead batteries. These spent materials are recovered and regenerated in a water-based recycling process to produce ‘battery-ready’ lead oxide.

The process, dubbed FenixPb, offers low start-up costs (around 1/7th) in comparison to smelting, and similar operating costs. It is ‘energy positive’, generating up to 5,000 MWh of thermal energy per 10,000 tonnes throughput; also, it is zero-waste; does not produce noxious gases; and reduces the carbon footprint by approximately 85%.

 

The Aurelius hydrometallurgical process

Conventional recycling uses high temperature smelting at around 1,200 ⁰C. High levels of slag, noxious gases (e.g. nitrogen dioxide and sulphur dioxide) we well as lead fumes must be controlled. This process is energy- and capital-intensive, and has a high impact on the environment.

Our approach, FenixPb, desulphurises the battery paste before passing it through a series of chemical treatment steps in water media. The lead is firstly dissolved to extract impurities, and then the pure lead salts are converted, via chemical reaction with citric acid, to a pure lead citrate.

“FenixPb is unique in that we are capable of producing a 99.99% lead compound directly from spent batteries. We do not generate any waste – even the battery plate additives are separated cleanly from our reaction,” says Technology Director Dr Athan Fox.

Next, the lead citrate thermally degrades to produce lead oxide of various compositions required by manufacturers. The project’s demonstrator has yielded a continuous flow of around 1.5 tonnes per hour of pure lead oxide – equivalent to 25,000 tonnes per year of battery throughput. Meanwhile, battery manufacturers can expect an increase in energy density due to the nanostructured nature of the FenixPb lead oxide.

 

Benefiting consumer, business and the environment

The FenixPb process increases the amount of recycling that can be safely undertaken in Europe, complementing existing infrastructure, without displacing jobs. Our goal is to make the process commercially available later this year, with a key franchisee in each economic area, whether a country or group of countries. At present we have approximately 60 expressions of interest, with 12 key licensees under consideration.

“To achieve our vision of a world without waste, we will also drive research forward on new battery designs and materials for use with our nanostructured lead oxide,” says CEO Mr Miles Freeman.

 

The future of lead batteries

We estimate that around 40 million tonnes of lead metal are currently in circulation globally. This includes lead metal in scrap batteries, lead ingot which is currently in warehousing and lead batteries in use or on the shelves. These 40 million tonnes comprise one of the finest and oldest examples of a circular economy.

What might happen if new and alternative battery chemistries become cheaper, better and safer? Will the lead battery disappear? And where will the surplus lead go?

Unless the lead metal is used in secondary LABs, it would become redundant at best or a health hazard at worst. But this wouldn’t make any sense – because, after all, lead metal is “infinitely recyclable and the economics work.”

 

If Cleantech solutions can help modernise the incumbent recyclers by making them cleaner, less wasteful, more efficient and economically superior, we are likely to continue using lead batteries for the foreseeable future.

 

A recycled lead compound – the lead citrate after it goes through the filter-press

 

Aurelius Plant –  the hydrometallurgical plant for recycling lead-acid battery paste. Based currently in Wolverhampton.