TECK CORP. The Biggest and the Best

When Cominco’s new lead smelter at Trail, B.C., opens in early 1989, it will mark substantial completion of a half-billion-dollar modernization of the world’s largest zinc-lead metallurgical complex. It should also mark the beginning of consistently brighter years for Cominco. The company has lost money in four of the past six years (before extraordinary items), mainly because of depressed prices in zinc and lead, and in part because of high costs at Trail. The significance to Cominco of the Trail metallurgical complex is illustrated by the fact that about 85% of Trail’s zinc production, and 77% of its lead, originates from Cominco mines. The Trail complex also produces about 325,000 kg of silver and 1,000 kg of gold annually at full production as by-products.

The new lead smelter is included in the first of a 2-phase program costing $260 million. In the first phase, new but proven technology will replace obsolete facilities, resulting in substantially improved productivity and working conditions. The design capacity of the new smelter is 160,000 tonnes annually, or 25% more than current smelter capabilities.

Cominco completed its new zinc electrolyte and melting plant at Trail in late 1983 at a cost of $210 million. Its capacity is 272,000 tonnes of refined zinc. The first phase of the new lead smelter program will feature a new and alternative lead-smelting technology called oxygen smelting or, more specifically, the qsl process. Construction began in August, 1986, and the cost is estimated at $171 million. The present lead-smelting operation treats lead ore concentrates to produce lead bullion that is refined in the lead refinery. The smelting process includes proportioning and drying of the feed, sintering to remove sulphur, and reduction in blast furnaces with coke to produce lead bullion and slag. The slag is further treated in furnaces to recover zinc. The lead bullion is refined to recover lead, silver and gold.

In the qsl process, oxygen smelting combines into one reactor or vessel the sintering and blast furnace operations. The reactor is a large horizontal steel cylinder lined with refractory brick. Lead concentrate, zinc plant residues and fluxes are fed into the top of the reactor while oxygen is injected through a liquid slag bath at the bottom. The resulting reaction uses previously wasted energy to produce a high-temperature slag and lead bullion which are tapped separately from the vessel.

The qsl process has a number of advantages over conventional lead- smelting technology. It has low energy requirements, it greatly reduces handling of materials, and it improves working conditions by eliminating the sintering and blast furnace operations that are currently major sources of airborne in-plant dust at Trail. A significant by-product of the qsl process is a low volume of very high- strength sulphur dioxide gas which will be processed at a $40-million sulphur gas treatment facility completed in 1985 as part of the zinc refinery modernization. The sulphur dioxide portion of the gas stream will be used to manufacture sulphuric acid.

In addition to the reactor vessel, a supplier-owned air-separation plant will be built and operated by Cominco on a nearby site. The $45-million cost of this plant is included in the $171-million cost of the first phase. The new system will also require pressure-filtering of the residues, a gas-cooling and cleaning system and lead bullion-handling facilities.

Phase two consists of rebuilding the slag-fuming furnaces and new coal- grinding and drying facilities at a cost of about $89 million. No timetable has been established for phase two.

The qsl process is named after the last name initials of its originators. Paul Queneau and Reinhardt Shuhmann Jr., two American professors from Dartmouth College and Purdue University, are the inventors of the unique lead smelter process. It was developed further in West Germany by Lurgi Chemie GmbH which operates a pilot plant at Duisburg.

Lurgi’s pilot reactor is 22 m long by 2.5 m in diameter. Cominco’s reactor will be similarly shaped but larger, measuring 40 m long by 4.5 m. It is the second commercial-scale plant of its type; the first is already under construction for China. Its capacity is 52,000 tonnes.

Cominco has been aided in meeting the cost of the lead smelter modernization by both the British Columbian and federal governments. They have agreed to purchase redeemable preferred shares in Cominco amounting to $55 million and $79 million respectively. Cominco Engineering Services Ltd. is responsible for engineering and construction. About 240 people, most of whom are already on Cominco’s payroll, will be working on the construction phase during the peak of activity in 1987-88.

The potent combination of efficient zinc- and lead-smelting and refining facilities and a long-term, low-cost supply of concentrates from the Red Dog deposit in Alaska, beginning in 1991, should assure Trail and Cominco of prosperity well into the 21st century.