Canadian Mining Journal

Feature

“Green” Lead Removes Tarnish

Mining giant Teck built its business by mining zinc and, more recently, coal, but what most people don't know about the company is that it also has a "greener" side to it because it is now one of the larger "recyclers" of lead in Canada as well.


Mining giant Teck built its business by mining zinc and, more recently, coal, but what most people don’t know about the company is that it also has a “greener” side to it because it is now one of the larger “recyclers” of lead in Canada as well.

Not “recyclers” in the curb-side, blue-box sense, but on a much grander scale thanks to its lead-acid battery recycling program, where it recovers enough lead from used vehicle batteries gathered from around North America to account for up to 20 % of the 360 tonnes of lead metal it produces per day at its Trail Operations.

From this massive facility located along the banks of the Columbia River in Trail, BC, Teck operates one of the world’s largest fully integrated zinc and lead smelting and refining complexes.

Beyond that, however, and in addition to its lead acid battery recycling, it also houses a new recycling processing system to reclaim metals contained in “urban ore;” more commonly known as electronic waste, such as computers and televisions, as well as zinc alkaline batteries and fluorescent light bulbs.

For a mining company, recovering metals from scrap is quite a break from tradition, but Teck is proud to have taken the lead in this respect, because reclaiming metals from waste is not only socially responsible by keeping them out of landfills, but recovering the valuable metals is also good for business.

In fact, Teck is so committed to its recycling program that it recently announced plans to invest $210 million into its Trail Operations to significantly increase its capacity to recycle end-of-life electronic waste.

Construction of two furnaces, a slag-fuming furnace and a settling furnace are all part of Teck’s No. 4 Furnace Project that gets underway this year and is expected to approximately triple Trail’s current capacity to recycle e-waste when completed in 2014.

The project will require about 500,000 hours of construction over the next two years, which equates to approximately 200 jobs during construction. More than 1500 people already work at the Trail Operations site.

The metallurgical operations at the facility also produce a variety of precious and semi-precious metals, chemicals and fertilizer products, but it’s the prospects for the advances in lead recovery right now that have generated local and, in fact, international interest.

Greg Belland, General Manager of Teck’s Trail Operations explained that the zinc operation is based on standard roasting, leaching and electrowinning technology, but it also incorporates direct pressure leaching of zinc concentrates.

“From a technical description, recovery of zinc contained in the iron residues is achieved through lead smelting and slag fuming. The zinc contained in fume is recovered in an oxide leaching plant and the zinc-containing electrolyte from both the pressure and oxide leaching plants is processed through the calcine leaching plant (known at Trail as the sulphide leaching plant) with the roaster calcine, purified and delivered to the electrowinning plant,” said Belland.

He went on to say that Trail’s lead smelter employs a KIVCET flash smelting process where dry feed, flux, coke and internal recycles are fed to the furnace with oxygen.

“In the furnace, impure lead bullion and slag are formed and separated. The molten slag is transferred to a slag fuming furnace where zinc is recovered as an oxide fume, which is then processed in the oxide leaching plant.

“The resulting barren slag is sold to cement manufacturers and the lead bullion from the KIVCET furnace is transferred to the continuous drossing furnace, where copper is removed with sulphur as a matte phase.

“The resulting bullion is further treated to remove impurities and cast into lead anodes for lead electrorefining,” said Belland.

As stated at the outset, Teck’s Trail Operations is doing great things thanks to its lead-acid recycling and e-waste recycling programs, and as Greg Belland concludes: “By-products of the lead-refining processes include silver, gold, and compounds of copper, arsenic and antimony, and they’re good for business too.”


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