Roundtable Discussion – Understanding Slag

Join live today:

Slag is one of the Lead industry’s significant, if not the greatest, enigma and challenge to a smelting operation.

Each smelter in every country across the globe faces different challenges with this waste material, whether it be silicate or sodium-based, absorbing the sulphur from the charge or just aiding in the removal of impurities, slag is still a key element in the smelting process playing a critical role.

One of the main issues for many smelters worldwide is understanding slag chemistry, a complex, understudied subject with very few experts. To complicate matters further, most of the world’s slags are technically not slags but matte. Add to this everyday sampling, leach tests, dumping and disposal problems, it’s easy to see why this material is challenging to many secondary smelters.

Four years ago, at the 6th International Secondary Lead Conference, there was strong sentiment among the delegates that a coordinated effort to understand and study slag/matte would be very welcomed and indeed supported. Like many topics and activities, Covid hindered our progress on this subject, but with the 8th Conference in Cambodia this year, a Slag Roundtable session will be convened to discuss how we can drive this initiative forward. Topics that may be covered include;

  • What does each operation do with the material?
  • Analysis, sampling and testing
  • What is our understanding of lead slag/matte?
  • Global Government Requirements
  • Disposal requirements around the world
  • Who are our “subject matter experts”?
  • How can the industry launch projects and studies, and how do we fund them?
  • What are our urgent problems and possible solutions?
  • How can we work collaboratively together?

No one person or company has the complete solution to this problem, but with the knowledge, effort and wisdom in our industry, working together, we can form a better understanding of the waste and generate solutions to sustainably handling this product.


Doug Lambert Independent Consultant

Doug Lambert joined Oldham Batteries (Denton, Manchester, UK) in February 1977, and now has over 46 years of experience in the lead-acid battery industry. He has worked for battery manufacturers and battery manufacturing equipment suppliers, and is now an independent specialist lead-acid product design and process technology consultant.


Darren Nelson Director, Nexus Recycling

Darren Nelson has spent the last 28 years operating and managing lead and zinc smelters. Starting his Chemical Engineering career in 1995 with Pasminco, at the Cockle Creek smelter, Darren operated the Imperial Smelting Furnace before moving on to metal refining and casting. In addition to Cockle Creek, Darren also worked at the Budel Zink and Port Pirie smelters also owned by Pasminco (now Nyrstar).

In 2007 Darren moved to the secondary lead world, managing the smelters of Australian Refined Alloys, then was appointed General Manager, in 2012, of the Enirgi Power Storage Recycling business, operating the Engitec desulphurisation system.

In 2022 Darren built and commissioned the Nexus Recycling business in Perth, Australia, utilizing the Wirtz battery breaker. Darren also operates his own engineering consulting business, Anglesite Management, specialising in lead smelting and all aspects of battery recycling.

Brian Wilson Consultant, International Lead Association

Brian has been working in the Lead Industry for the past 40 years, initially with Britannia Refined Metals in the UK, then the International Lead Zinc Research Organization and for the past 15 years for the International Lead Association. Brian is also a member of the Pure Earth Technical Advisory Board and as an Independent Consultant has been engaged by the Basel Secretariat, UNEP, ERM, the OeKO Institute and Pure Earth. During the last 40 years Brian has worked in every continent except Antarctica and no less than 51 different countries.

Mr Mark Stevenson CEO, Global Lead Technologies

Mark Stevenson has been involved in the lead smelting and battery industry for the past 44 years. His career has covered all facets of primary and secondary lead research and production and battery development working in numerous roles over these years. He is currently the Technical Director for Global Lead Technologies consulting to many companies around the world on best smelting practices for lead. He holds numerous positions throughout the world including Chairman of the Asian Battery and Secondary Lead conferences.

Dr Sander Arnout CEO, InsPyro

Dr Sander Arnout is CEO of InsPyro and a founder of this KU Leuven spin-out established in 2009. The company aims to assist industrial customers to improve and develop metallurgical processes. It does so based on practical experience and mainly by creating insight, using scientific modelling and characterization tools. InsPyro has cooperated with many larger and smaller players in the primary and secondary lead and lithium industries. Sander holds a MSc in Materials Engineering and a PhD in the field of metallurgy.


Joe Grogan Chief Technology Officer, Gopher Resource


Davi Trindade Antares

Silver Sponsor