Record numbers turned up for the 8^th International Secondary Lead & Battery Recycling Conference, Recycle100. Conference chair Mark Stevenson said he had received “a phenomenal response” for this and the Asian Battery Conference. This includes feedback with practical suggestions and new ideas. “I’ve never had this before,” he told BEST. Andrew Draper reports.

The event, held in Siem Reap, Cambodia, in September, hosted 242 people from 30 countries, representing 150 different organisations. Around 100 joined online for the panel session on slag. The exhibition area was sold out. Conference organisers had arranged extra internet bandwidth for the 90‑minute roundtable.

Following a musical entertainment by Cambodian musicians in traditional dress, Stevenson opened proceedings by saying the international secondary lead industry is “a true metallurgical operation” and not waste treatment plants.

He told the delegates they were part of an $18 billion industry. “It’s often not appreciated,” he said. “Our products are called waste but we shouldn’t call them waste.” He said the term is rarely used in the lithium battery sphere. “There are people in this room – traders and buyers – who will buy it.” Even the United Nations uses the term waste, but that is no excuse, he said.

He added he gets very frustrated when he reads academic papers and journals that are factually wrong. For example, an Indian paper stating that there is a 25% recycle rate in China (it is over 95%), or another referring to refinery dross as a waste product. Such papers are then cited multiple times.

“For me, hopefully we can change that and show the world we are a proper industry.”

Recyclers of the world unite: you have nothing to lose but your slag

A round table discussion on slag at the Recycle100 Conference is leading to the birth of a slag working group.

A panel discussion and lively Q&A at the conference addressed the question of what slag is, where it comes from, and what can be done with it.

Opening the discussion, independent consultant Doug Lambert said eight million tons of secondary lead production and slag is a challenge. “This round table…will lead us towards improving the secondary lead production process,” he said.

Sander Arnout, CEO of InsPyro in Belgium, said typically slag and matte comprise molten oxides and molten sulfides respectively. “It contains everything that we have in raw metals that’s not metal,” he said.

Chairing the conference, Mark Stevenson called on the industry to come together and build a nomenclature and knowledge bank. He told the round table he saw no way of making money from slag, while Joe Grogan, chief technology officer at US-based recycler Gopher Resource, said his company was working with different types of slag and commercially exploiting the product. Gopher Resource won the 2023 BCI Innovation Award for a process that cleans slag.

It has patented a process called SCRUM (Slag Cleaning and Recovery of Useful Metals). It separates the tin and lead as a concentrated fume. Some projects create slag worth $20–100/ton, he said.

Grogan later told BEST: “The slag council offers a constructive forum for participants to share best practices and discuss the latest developments in the industry. Through meaningful engagement in the council, I believe that companies may identify real opportunities to enhance their businesses. In recent years, Gopher Resource has invested in research efforts to better understand our slags to drive improved operational and environmental performance. Our SCRUM technology is one product of those efforts and we’ll be sharing information about SCRUM with the council.”

Stevenson invited interest from the audience for a working group and received an enthusiastic response. It would consist inter alia of a members’ forum for sharing papers, projects, and test work. Separating out tin was “the big holy grail”, he said, adding that it can be a nightmare.

Setting the scene for whether global lead battery recycling rates are up or down, Huw Roberts of CHR Metals told delegates the few dedicated studies of lead battery recycling point to recycling rates well in excess of 90% (very high 90s).

Of the 13.9 million tonne global refined lead production in 2022, 76% of that (10.6 million tonnes) is from secondary lead. He said a high share of the secondary is battery scrap, including lead recovered from other lead-bearing wastes, lead scrap and also some of the lead content of other concentrates such as from zinc or copper feeds going through primary smelters.

Falls in primary lead output (including lead recovered via primary smelters) in Europe and North America were unrelated to the pandemic, he said. But Covid impacted on secondary production in every region except China.

He said Indian imports of lead battery scrap surged in 2021–22, taking trade away from South Korea. This followed India’s relaxation of rules on battery scrap imports in 2016.

Roberts dealt with the Chinese market separately. Lead production from recycled batteries is understated in official data, he said. “There has been a massive increase in facilities for recycling in China over the last few years,” he said. “Almost every week we were hearing about a primary lead smelter being opened. There is more capacity now in China than there are batteries available.”

There are more than 90 operating plants and another 50 being planned or built, he said. Cumulative capacity is enough to break 30 million tonnes of scrap batteries – more than there are batteries in the world, he added.

In his presentation on lead recycling in China, founder and chair of Leoch Battery, Dong Li, said the secondary lead industry has become an important component of China’s lead industry. The proportion of secondary lead output in developed countries accounted for more than 90% of lead’s total output. But in China, in 2016 only around 40% of the market was recycled lead, while in 2021 it totalled 51%.

Referring to official data and analysis by Leoch Research Centre, he said: “The production rate of primary lead is going down, and the scale of recycled lead is expanding rapidly.” Recycled lead will become the main lead source for the lead- acid battery industry, he believes. By the end of 2018, more than 150 companies in China were collecting recycling lead licences in 21 provinces.

Primary lead production capacity is restricted by environmental protection requirements, where there is a shortage of capital, he said. The quality and production efficiency of the newly added domestic technology for recycled lead production lines are inferior to those of imported production lines.

Consumption rising in India

L Pugazhenthy (known as Pug), Executive Director of the India Lead Zinc Development Association, talked about how strong GDP growth in India was outstripping world rate. Data from the International Monetary Fund for 2022 puts India’s estimated GDP growth at 7.2% compared to a global 3.5%. This is fuelling consumption. The Indian lead industry has total lead consumption of 1.5 million tonnes.

New Battery Waste Management Rules were introduced in 2022 and cover all battery chemistries, not just lead, he said. The rules cover used and end-of-life batteries and apply to every producer, dealer, and consumers, as well as those involved in collection, segregation, transport and recycling.

All batteries must be recycled (no landfill or incineration). For auto batteries, a 30% collection target in 2022–23 will rise to 100% by 2028, with a similar target applying to industrial batteries. “The most important part of the legislation that is missing is on dealers and traders,” he said, noting all recycling responsibility is currently on battery producers. That omission is to be addressed, he noted.

Solvent-based recycling

Dr Ola Hekselman, CEO and co-founder of UK firm Solveteq, gave an update on her company’s progress on a method to dissolve spent lead paste and recover a lead salt with high purity.

Solveteq’s technology is based on the use of deep eutectic solvents, which were developed as a green alternative to ionic liquids. The process can work from room temperature to a maximum of 70°C and is designed to be modular and scalable.

The proprietary solvents were developed at Imperial College London to process de-sulphurised and sulphurised paste directly from the battery-making process and, depending on the requirements, can produce a metallic lead or lead oxide.

Hekselman told delegates they had simplified the system, which helps with moving liquids. The current phase is running at 1kg/hour but the plan is for it to be upgraded to a pilot scale processing 25kg/hour in 2024. A move to full commercial scale is envisaged for 2026.

Costs for processing are $0.37/kg of lead, more if not reusing the chemicals. “We’re convinced that with scaling up, we can drive down the costs,” she said. In terms of the results, they are achieving 79% conversion of scrap to metal lead, she said. The aim is 99.99%.

Alberto Bergamaschini, commercial director of STC, an Italian engineering procurement and construction management company, outlined his company’s products and services.

Its U4Lead process means the desulphurisation level obtained is higher than the traditional process (0.2–0.3% of sulphur remains).

There is a further reduction of slag generation (5–6% on lead produced) which cuts lead losses and iron usage, fuel, and oxygen. The by-product obtained is ammonium sulphate that can be sold and used as fertiliser, he added.

STC has teamed up with battery recycler Ace Green Recycling of Singapore. STC manufactures the recycling equipment, and provides overall engineering and project management activities. The two are exploring opportunities for licensing and co-marketing their battery recycling technologies.

STC designs and supplies turnkey plants, along with technologies and equipment for recovering lead, polypropylene, PE and other materials from exhausted lead batteries.

Comparing recycling technologies

Dr Nawshad Haque, Principal Scientist at CSIRO Energy in Australia, presented a paper comparing recycling technologies for end-of-life lithium-ion and lead-acid batteries. He said it is hard to compare two battery systems, and energy source is dynamic.

There is a lot of uncertainty about the carbon footprint of both primary production of lead-acid and lithium batteries and their recycling, he added. He called on the battery community to support and investigate these areas of research.

Flowsheeting, techno-economic and life cycle assessment (LCA) are major tools and methodologies in evaluating sustainability, he said. Industries lack skill for environmental LCA, particularly for new conceptual technologies, he noted.

He later told BEST these studies make it possible to understand the supply chain and manufacturing’s system-wide impact.

A tidal wave of EV battery recycling demand

The recycling market is due to be hit by a tidal wave of demand for recycling electric vehicle (EV) batteries and the market will not be ready for it, according to Farid Ahmed of Ace Green Recycling.

He said: “The colossal growth is going to hit us like a tidal wave. We need to react, and not just when it hits us.”

He told BEST he believes EVs are in many cases being used as second car “run arounds” and so provide better than expected battery longevity. Lithium-ion is growing so fast anyway, even though it is not as fast as many expected a couple of years ago. It means recycling lithium-ion batteries will gather pace quickly and then face a tidal wave of demand. “It will be 2032-ish when we feel it,” he said.

Asked if the recycling market will be ready for that, he said: “Not a chance. People aren’t going to build huge smelting capacity and have it sitting there hungry for years and years ready for the time when they are ready for their feed.

“That’s why we are enthusiastic about our modular concept. You can build up capacity.”

Each module is identical and has recycling output capacity of 1.5 tonnes of lead-acid batteries and half a tonne of lithium-ion batteries per day.” He said this stepped approach makes its systems accessible in poorer countries, where informal recycling exists.

Recycling in Africa

Engitec Technologies, which claims to have installed about 50% of the world battery recycling capacity, has launched a new smaller scale lead battery recycling plant and is finalising the first contract for a small-scale recycling plant in west Africa. It will include the foundry, the refining, and the ingot caster.

Stefano Buono, Area Manager for Engitec Technologies, said the CX Smart is aimed at smaller customers in emerging countries with limited capacity. It can handle 12,000 tonnes of batteries a year, corresponding to the production of up to 6,700 tonnes per year of soft lead/alloys and up to 600 tonnes per year of polypropylene recovered.

It can cast four tonnes of ingots per hour, collect and filter electrolyte, separate components, filter lead paste and smelt lead. It has scrubber filtration and a 1.5m³ rotary furnace. This CX Smart plant is much smaller than Engitec’s biggest CX 50tph breaker, which can handle 50 tonnes per hour.

Buono said he believes the CX Smart will be well received. It will be available for commission next year. “It’s targeted at emerging markets where logistics can be a problem in areas where batteries are restricted to a territory.”

He said the cost of the CX Smart breaker will depend on the scope of the supply but could amount to €4–5 million ($4.3–5.4 million).

Africa’s increasing profile in the international economy featured in the conference. Vijay Kumar Pareek, executive director of Gravita India, set out his company’s expansion into African lead recycling.

Noting how European colonialists had carved up Africa, he then pointed out Africa’s high share of world resources: 90% of the world’s cobalt, 90% of the platinum, 50% of the gold, 98% of the chromium, 70% of the tantalite, 64% of the manganese, 34% of the uranium, and 30% of the world’s diamonds. Guineau is the world’s largest exporter of bauxite, he said. Despite this, Africa is the world’s poorest and most underdeveloped continent.

The major recycling countries are South Africa, Egypt, Nigeria, Ghana, Algeria, Morocco, Senegal, Mozambique, and Tanzania, he said. Industrial challenges include scattered availability of raw materials, poor connectivity with the rest of the world and lack of skilled labour. Transport and logistics are poor, the financial system lags the rest of the world, and Africa does not consume the metal it produces. Europe, Asia, and America do that.

Gravita has been in Africa since 2003 and has built an 80,000 tonne recycling capacity. It processes lead, aluminium, plastic and rubber, and exports worldwide.

Many conversations on the conference side-lines confirmed the view that informal recycling in Asia is retreating and being replaced with an increasingly regulated and organised system.

Stevenson told BEST it cannot be overemphasised that secondary smelting is a complex operation, although it may seem relatively easy on the surface “Around 40 years ago, the sector started to formalise plans and operations, and in recent years, dedicated engineering companies began to develop and offer turnkey operations for the construction of complete secondary plants. These plants now incorporate the latest technologies in smelting, scrap treatment and pollution control, with many older furnaces now phased out.”

The keynote presentation by Sander Arnout of Belgian company InsPyro very neatly applied the laws of thermodynamics to describe the theoretical constraints of conventional high-temperature pyrolytic extraction methods, which prevent heavy metals from ending up in the slag.

Arnout said, typically, slag and matte comprise molten oxides and molten sulfides respectively. For hydro, he explained, the advantages relate to lower energy use, lower dust levels and the possibility of producing very pure metals by selective electrolytic methods.

Recycling lead-acid batteries has two options of pyro and hydro metallurgical routes, each with its own merit. The pyro option has fewer steps, removes organics, and achieves low impurity levels. The problem is the slag, but metal contamination of the slag can be minimised with better understanding of the thermodynamics of the processes.