Mark W Stevenson talks to Andrew Draper about his 45 years in lead battery recycling, his frustrations at lack of scrutiny and peer review, and his ongoing wrestling with how to deal with slag from secondary lead.
Mark Stevenson has worked with some top names in the industry, including Pasminco, Nyrstar and Ecobat Tech, and is now technical director of his sole-trader company, Global Lead Technologies, in Melbourne, Australia. He spends much of his time consulting and advising companies on lead recycling operations, and acting as technical expert in legal cases.
He is also well known as chair of the Asian Battery Conference (ABC), which is held every two years. That has been his baby since 2002. The International Secondary Lead Conference (ISLC), which he has also chaired since 2005, runs alongside ABC.
To say he has a fire in his belly for lead-acid battery recycling is putting it mildly. It is this passion that makes Stevenson so frustrated and mad at what he calls a lack of peer review and data scrutiny.
This is why he has decided to write a technical book explaining the metallurgy behind secondary lead. “The problem is, what I don’t like in our industry is we don’t control the narrative going out…If you just put lead in Wikipedia and you read that, you’re horrified. There’s nobody from, say, respectable lead who actually is quoted there and who’s done things properly,” he said.
“They’re quoting obsolete journals and they’re quoting other things that you look at and you think, my God, we could write a better narrative on lead ourselves. So I really want to start taking the narrative back and look to give you a great indication of the stuff that gets published out there.”
He has an extensive private library of books on lead technology (some 400 titles), and has picked up books as specialist libraries closed down (often owned by companies modernising records), and saved them from being thrown out. “I would say I probably have one of the biggest private collections of lead data and lead technical books in the world. Because they came from those libraries and they were just getting rid of them, they were throwing them into skips and bins. It was very sad.”
No proper scrutiny
He is highly critical of new developments, such as the emergence of lithium battery technologies, that do not get proper scrutiny. “It’s all lovely and fluffy,” he said. “Look what we’re doing in lithium now… What bothers me especially, and is one of my big bugbears at the moment, is there is no scrutiny of data. There’s no scrutiny of papers, there’s no scrutiny of processes.
“And I blame PowerPoint for it. You get 20 slides put up and you can throw 18 away, and there’s two slides that might be worth something, and then people go off and make decisions based on that.” Years ago, there would be a proper journal – paper print – to go through properly and read.”
He added: “And have a look at the people who say ‘yes, I saw it. Oh, I looked at the PowerPoint, looked at this process.’ Are you kidding? You honestly kidding? There’s no peer review of anything anymore. There’s no papers published to say, okay, well let’s have a look at what we’re doing now. Let’s scrutinise it where we are.”
Major interest is slag
One of Stevenson’s major interests is dealing with slag. He organised a technical round-table discussion at the 2023 ISLC and a new body is emerging as a result. Stevenson has had family issues to deal with since then, so has not made much progress, but is about ready to take up the work again. It will act as a forum to share ideas and knowledge.
It was initially dubbed ‘the slag council’. There was some shyness to ask questions at the round table, he said, but he had people lining up to talk to him afterwards. He has also had interest from around the world. “I think people will jump at it if they know that research has been done into what we’re talking about. They will be on it very, very, very quickly.”
The problem, he said, is understanding slag. “Slag chemistry and slag technology are extremely complex. You know, even a lot of smelters don’t even understand the reactants going on in the furnace. There are metallic reactions, and no understanding what’s happening in the slag. The slag itself is a whole different matrix of what’s going on.”
Many smelting companies, especially small ones, lack the technical expertise and understanding of what slag chemistry is and the reactions in their furnaces. “And it’s not through their own fault,” he said. “It’s just the way this industry falls together. The reactions that occur in the furnace are complex, but they occur. I call it the four S’s and they’re the problems with the slag: separators, sulphate, sulphur and simplicity.”
Simplicity refers to the simplicity of the system that occurs and leads to a lot of people thinking they’re doing a good job because they’re getting lead out of the furnace.
He does not believe the interest in slag is financially motivated, though no-one would be against making some money out of it, he said. It is more about understanding and resolving a problem where slag cannot be disposed of in landfill as it contains toxins.
It is also understanding the difference between slag (mostly mixed oxides) and matte (a crude mixture of molten sulphides). “I think hopefully we can get a lot of research to understand how to treat slags better, how to reduce the lead slag. How to understand what we’re doing, the dynamics. I think that’s the area where we are going to improve.”
Massive improvement
Stevenson has witnessed “a massive improvement” in environmental impact and health and safety in the lead battery industry over the past 40 years. It should be extremely proud of itself, he said. The improvement, he said, applies across the board: knowledge, equipment, workers’ health, plant design, understanding dynamics of airflow and even mask wearing.
Blood lead levels were measured and posted on a notice board in his younger days. “If you didn’t have a high blood lead level, people would say, you’re not working hard enough,” he said. “And it was almost like a bit of a peer group to actually say, well, you’re not working hard. Your blood lead’s only 26. And I mean, I can go back to the days where we were talking commonly over 70. That’s absolute bollocks.”
According to the US National Institute for Occupational Safety and Health, 0.855µg/dL was the typical blood lead level in the US among adults in 2017–18. Medical removal is recommended if a worker has two consecutive blood lead level readings of 20–29µg/dL.
One of the things Stevenson does is appear as expert witness in court cases. In one case, the opposition technical witness told the judge that workers could drink from a cup made from lead and not suffer lead poisoning. Stevenson pointed out that some workers shower three times a day to avoid lead poisoning. He attacked the witness for being “so stupid” and was later commended by the judge. The barrister in the case later wrote to Stevenson and pointed out it is extremely rare for anyone to be praised in that way by a judge.
“That’s probably the peak of my career for me professionally, because when I talk or when I do things here, after a while people come and say, oh, nice talk Mark. You think, okay, you’re part of the industry. Thanks, you’re just being kind. And you probably realise I don’t take gratitude very well.”
Handing over ABC
Asked about his plans for the ABC, Stevenson said at some point he will be handing over the reins. “I want people to come to the ABC and enjoy it because, at some point in time, I have to give it to somebody else to take over.” He is already in discussions and his bottom line is: the right person must also have fire in their belly.
“I’m 62 now, getting on. You do two more and you’re 65. We’re not infallible. And you know, my grandfather passed away at 62 and my other one passed away at 64. I’m 62, I’m right in that zone. I’m not saying, but you know, you’ve always got to be prepared.”
He compares ABC and ISLC to football teams, where teamwork rather than any individual produces the results. Part of his approach is to draw on the experience of industry veterans and of new people in the industry with fresh ideas.
Lessons learnt
Asked what lessons the other chemistry sectors can learn from a mature lead industry, Stevenson said lithium is “a great example.” He added: “The lithium guys are getting so much coverage, so much money, so much energy being spent on them. And it’s all bollocks. It simply is that there’s no intrinsic value. How do you get that intrinsic value to recycle? I don’t care about the papers. I don’t care about all the stuff: there are recycling machines that will do it, but it costs money.”
The cost of recycling lithium batteries is more than the proceeds, he believes, adding “you won’t find a scrap price for lithium”.
Stevenson is so keen for the industry to find a solution to dealing with slag, he thinks he will die with it on his brain and ‘The Old Slag’ will be written on his headstone.
