One of the most immediate challenges facing the global lead industry is environmental impact, Jerry Pyatt, COO of The Doe Run Co, told attendees of the Lead-Zinc 2010 Symposium in Vancouver, British Columbia, this month. “After years of careful research and 200,000 hours of practical application by Doe Run, we are on the verge of replacing traditional, high-temperature lead smelting with a proprietary hydrometallurgical process,” said Pyatt.
Pyatt’s technical presentation to metals industry colleagues was the first on Doe Run’s proprietary new lead processing technology, which company officials expect will transform the way the world manufactures primary lead metal. Jose Hansen, vice president of sales and marketing, presented on the technology at the International Lead-Zinc Study Group in Lisbon, Portugal, on October 8.
Pyatt and Hansen unveiled details behind Doe Run’s technology, the company’s work with research partner Engitec, and how the technology transforms the centuries-old, heat-based process into a hydrometallurgical process. Since more stringent environmental guidelines are making traditional smelting obsolete, and global refined lead demand is expected to grow from 9.3 Mt in 2010, to close to 17 Mt in 2025, the technology is needed now more than ever to satisfy global demand.
“Planning for the future requires us to consider challenges,” said Pyatt. “The new technology supports lead production in a clean and sustainable way, and outperforms anticipated regulatory standards.”
Lead plays a vital role in modern conveniences around the world, including startup power for vehicles (including conventional, hybrid and micro-hybrid models), backup power for hospitals and telecommunications, lead shielding to block sound waves, X-rays and nuclear radiation, and alternative energy storage for wind and solar power.
“Doe Run’s technology would ensure a domestic supply of primary lead for our US based industries,” said Pyatt. “And a domestic supply could help bolster research and development for alternative energy storage, and create more jobs.”
The advancement uses a technology that has never before been applied to lead – leaching and electrowinning. Pyatt and Hansen described the three main steps in the process:
- Leaching: The Doe Run technology is fed by lead sulphide concentrates, which are selectively dissolved into fluoboric acid. One of many benefits associated with the process is the fact the reagent used (fluboric acid) is very stable at operating temperatures and is benign if it comes into contact with skin
- Electrowinning: The lead-bearing solution is treated in an EW process, which recovers the lead into pure cathode sheets. This process is similar to the technology used to extract zinc from concentrate, but has never been used in primary lead production
- Recovery/Co-Product Treatment: Co-products such as zinc, copper and silver are recovered. The process is self-contained, and the solution can be recycled back into the process indefinitely.
The Doe Run technology is highly efficient; recovery of lead directly to a finished product is approximately 99%, compared to 95% with traditional smelting.
Since Doe Run and Engitec began studying the concept, the development of the new process has entailed laboratory development and testing, design, construction and operation of a pilot plant, and design/development of a demonstration plant.
To prove the technology works on a commercial basis, Doe Run has invested more than $30 million in the demonstration plant, engineering studies and the design of a commercial-scale processing facility.
Doe Run is completing a detailed feasibility study, slated for the year’s end. To take the project to a commercial-sized operation, the technology will require investments of more than $150 million. Doe Run is actively pursuing funding and loan guarantees.
This year, global demand is growing by around 5 to 6%. Doe Run officials expect global lead demand to increase at a similar pace in 2011. Much of this need is due to consumption in China, where the vehicle per capita rate is still much lower than the U.S.
“By bringing the new process online, we can keep the US at the centre of the global lead industry and help our region continue to benefit from some of the richest lead deposits in the world,” said Hansen. “We are the largest integrated lead producer in the Western Hemisphere, and we have a vested interest in technology that will improve production.”
