Andrew Draper meets the chief technology officer of Gopher Resource, Joe Grogan. They discuss research, cleaning slag, extracting tin and being part of the conversation.
Since talking to the International Secondary Lead Conference (ISLC) in Cambodia last September, Joe Grogan has had lots of interest worldwide from people looking for ways to get tin out of slag.
Achieving that remains elusive. Gopher Resource, headquartered in Eagan, Minnesota in the US, is working on ways to achieve it and bring it to market. Grogan emphasises circular benefits of the project as well as the economic benefits. He points to the international and collaborative nature of its research in pursuit of this.
“We do try and take an open innovation model in a lot of what we do, especially on the environmental and safety side of things,” he said. “We do see, actually, a decent amount of collaboration there.” Gopher was one of the early members of the Center for Resource Recovering and Recycling (CR3), where it gains access to tailored research, technical expertise and industry knowledge, which it believes is a complement to its own research and development. Among the membership are big name companies such as Aurubis, Boliden, East Penn Manufacturing, Ecobat and Umicore.
Much of the work is ‘pre-competitive research’, for example: on slags from recycling, and performing better measurements of material flows and developing first principle in a thermodynamic or kinetic data, according to Grogan.
Has a quarter of all US production
Gopher was founded in 1946 and has lead battery recycling plants in Tampa, Florida, and Eagan, Minnesota (the place where it started). Each year, the company recycles more than 25 million batteries, producing about 300,000 tons of recycled lead. That equates to around a quarter of all US production.
It works on defence contracts too. “We’re working with the Army Research labs and we have a number of projects at different locations across the world where we’re looking at things like slag valorisation – taking our slags and turning them into engineered products such as paving stones.”
Another project, in conjunction with Australia’s University of Queensland and other companies, is looking at understanding the thermodynamic properties of its slags. Grogan said the idea is to develop shared databases to better understand slag. That in turn will enable better recovery, better environmental properties and so on.
Gopher is claiming high rates of recovery in its secondary lead recycling – in the 90s percent-wise. Grogan said tin remaining in secondary lead slag is typically around 1-3 weight percent of the slag.
“Tin is still there. And it’s a chronic problem across the industry. Everybody is doing what they can to get the lead out. And I have lots of phone calls from lots of people all around saying, ‘Hey, you know, what do we do to get the tin out?’”
He said it reemphasises that this is something the industry could work towards solving. Discussions with such callers are at an early stage. They began after Gopher won the Innovation Award at the 2023 BCI convention for its work on cleaning slag. Grogan also addressed the matter in a round table discussion on slag at last year’s ISLC.
Following the ISLC, conference chair Mark Stevenson took the initiative to set up a working group on slag, and Grogan has thrown his weight behind that. He said he hopes a lot will come from this.
SCRUM process
Gopher has patented a process called SCRUM (Slag Cleaning and Recovery of Useful Metals). It uses furnace fuming technology to separate the tin and lead into a concentrated fume form, leaving behind a ‘cleaned’ bulk iron sodium-silicate which it calls ‘SCRUM slag’.
The SCRUM process in pilot testing has removed up to 99% of the tin in the slag via a propriety evaporation (or fuming) process, which removes the tin as a concentrated condensed dust (or fume). The equipment used in SCRUM is the same and familiar to existing secondary lead recyclers, Grogan said.
The resulting LME-grade tin and lead bullion can be refined and used in new lead batteries. The remaining SCRUM slag is, it claims, a clean byproduct that can be repurposed as aggregate in roadways or in concrete building materials. It sees promising potential for commercialisation.
Gopher says the process has the potential to prevent more than 100,000 tons of lead and 30,000 tons of tin from entering landfill globally each year and reduces greenhouse gases through material recovery.
Grogan said the enquiries about separating tin are aimed at genuine collaboration with Gopher rather than people fishing for information.
Metallurgy, whiskey and rugby
Grogan is a father of two young children and comes from Tullamore, a town in Ireland famous for a whiskey called Tullamore Dew. He comes from a multi-generational farming background and the family now run a beef demonstration farm (next to the distillery) for the Irish Farmers Journal.
He holds a patent on zinc recycling and has others in the pipeline. He also has more than 20 industry and scientific publications, primarily in lead and zinc processing. His master’s thesis was on lead slag recycling, and the doctoral thesis was on zinc scrap recycling.
He did a PhD in metallurgical engineering at the Colorado School of Mines, where he also played prop forward for the Mines Rugby Team. He worked as a mining consultant engineer in Cardiff, Wales, from 2008–11. He also played rugby there and points out that the toughest rugby he has played was in the south Wales valleys. (Editor’s note: I live in the south Wales valleys and can confirm the correctness of his statement).
Carbon footprint reduction
Gopher is working to reduce its carbon footprint. Heat recovery will aim to make recycling processes more efficient. It has teamed up with University of Minnesota Natural Resources Research Institute (NRRI) to study the use of charcoal from biomass as an alternative to burning fossil coal in its recycling process.
Historically, conventional charcoal was used as fuel and reductant in pyrometallurgical operations to produce metals like cast iron or copper. It was replaced during the mid-1800s by coal or foundry coke, as they were better suited. Technological research advances have now led to highly engineered charcoals like biochar. The researchers think it may again be a viable, cost-effective reagent, according to Gopher.
Biochar is created by combusting organic materials in a low oxygen environment using processes like pyrolysis or torrefaction. It is about 70% carbon. Gopher’s goal is to cut its direct greenhouse gas emissions by 30%. The biochar it is looking at will come from ash trees and balsam fir slated for removal due to disease and insect infestations. It will divert waste from landfill and help prevent wildfires in northern Minnesota.
Too many people retiring
Grogan is concerned at the large number of people retiring from the industry and not being replaced by young entrants. Gopher therefore offers some scholarships and funds graduate research to encourage interest in the industry among students. It regularly submits papers to scientific journals.
Grogan makes a point of attending conferences to collaborate and share ideas. “There’s a lot of great stuff going on out there,” he said. “And in some respects we’re passive, but in many aspects we’re actually very active… It’s really important to be part of the conversation and be outward looking and open to sharing, having conversations.”
He is also an active organiser of such events, and sits on the organising committee of the International Lead-Zinc Processing Conference series, which has been operating for over 50 years. He was co-organiser of the 2023 Lead-Zinc conference held in China last October and attended by 700 people. He said: “It was the first time the series was held in China and was a massive success.”
Speaking on the sidelines of the BCI centenary convention in May, Grogan said: “I’m walking around here and very impressed with what I see from the BCI and from the companies…I was at the Technology Innovation Summit in there, and I was really at the back just trying to absorb 20% of what was said. Some of it was going over my head, but they’re very, very sharp people and they’re doing a lot with the lead-acid technology platform.”
So what impressed him most? “I wouldn’t have the qualification to really go into it. But I can tell you all day long how to make all the lead alloys, but that’d be somebody else that will tell you all about the batteries.
“I mean, look, there’s a lot of innovation going on in terms of what people are looking at from a material standpoint: what they want in terms of material specifications. There are lots of conversations going on there. I know that’s stuff we would be involved with.”
That innovation does not get the same interest as lithium, he said. “But at the same time, I think that’s just part of where you are, in terms of the technological curves. But the guys here are doing a tremendous amount of work in terms of lead battery innovation.”
