Executives from U.S.-based lead producer Doe Run Co. recently presented further details regarding development of a proprietary new lead processing technology, originally announced in March.
Chief Operating Officer Jerry Pyatt told attendees at the Lead-Zinc 2010 Symposium in Vancouver, British Columbia, the most immediate challenge facing the global lead industry is environmental impact. “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. “Planning for the future requires us to consider challenges. The new technology supports lead production in a clean and sustainable way, and outperforms anticipated regulatory standards.”
Pyatt’s presentation 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, also presented on the technology at the International Lead-Zinc Study Group in Lisbon, Portugal, October 8.
Pyatt and Hansen explained details behind the technology, the company’s work with research partner Engitec, and how the technology replaces a centuries-old, heat-based process with a hydrometallurgical approach.
Doe Run’s approach uses a technology it claims has never before been applied to lead—leaching and electrowinning. There are three main steps in the process:
- Leaching - The technology is fed by lead sulphide concentrates, which are selectively dissolved into fluboric acid. One benefit associated with the process is the fact the reagent used (fluboric acid) is stable at operating temperatures and benign upon skin contact.
- Electrowinning - The lead-bearing solution is treated in an electrowinning 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.
According to Doe Run, the technology is highly efficient; recovery of lead directly to a finished product is approximately 99%, compared with 95% by 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.
The company 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 said it is actively pursuing funding and loan guarantees.
Global refined lead demand is expected to grow from 9.3 million mt in 2010, rising to about 17 million mt in 2025. This year, global demand is growing by 5% to 6%. Doe Run officials expect global lead demand to increase at a similar pace in 2011, with much of the growing demand due to consumption in China.
“By bringing the new process online, we can keep the United States at the center 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.”
Doe Run said the new technology is covered by process patents in the U.S. and a number of other industrialized countries. Doe Run and Engitec jointly own the intellectual property. Doe Run currently has an exclusive license to the technology.