COPPER DIVISION: CCR Refinery
Noranda’s 350,000-tonne-per-year CCR copper refinery near the docks in Montreal East is one of the world’s biggest copper suppliers. Its location at a major port in eastern Canada gives it freight advantages over other refineries.
A nearly completed $124-million modernization project has turned CCR (originally “Canadian Copper Refiners Ltd.”) into “a 70-year-old plant with a bionic heart” according to general manager Viken Baboudjian. “There is nothing else around the world like it.”
All the copper anodes from Noranda’s Horne and Gasp smelters are sent to CCR for refining. When Martin Guilbert, superintendent of engineering and central maintenance, showed CMJ around the refinery in mid-April, the plant was expecting its first shipment of anodes from the Altonorte smelter for testing.
“Noranda Copper has developed a market niche in treating complex feeds,” says Baboudjian. “This puts pressure on the refinery. In spite of the differences in feed, we have to continue to produce consistent quality copper, in order to meet the most stringent needs of our customers.”
The 333-kg anodes containing 99.1% to 99.4% Cu are received, weighed and sampled, an important step: the anodes from Horne actually have more value in precious metals than in copper.
The anodes are submerged in heated electrolyte solution in the tank-house cells for 20 days, interspersed between cathode sheets; the application of a 23,000-A current causes the copper to migrate from the anodes to the cathodes.
It takes seven days for a cathode to grow to 92 kg of 99.99% pure copper, so each anode produces three cathodes. Some of the copper cathodes are melted and cast into various shaped cakes and billets; the rest are simply packaged and sold.
The spent anodes are remelted together with impure copper scrap, and cast into new anodes to be sent back to the tank house.
Some of the impurities from the anodes-such as nickel, arsenic, antimony and bismuth-dissolve in the electrolyte and are recovered as salts. Other impurities settle as slime in the bottom of the refining cells, from which precious metals are recovered.
A resin plant completed last year at CCR removes antimony and bismuth from the electrolyte, opening up a window for the Horne smelter to accept materials with these elements.
The three-year modernization project (called “MCP” for modernization des cathodes permanentes“) will be completed at the end of July. This will make CCR the most automated copper refinery in the world.
One aspect of the MCP project is a change to the Kidd Creek Process permanent cathode technology. The Kidd process grows copper cathodes on reusable stainless steel sheets, and includes automated cathode stripping equipment.
The other main aspect is an automated material handling system engineered by Union Minire Engineering (UME) of Belgium, with equipment supplied by Femont, also of Belgium. This is replacing CCR’s old system of indoor rail transport and overhead cranes manned by an operator and assisted by ground crews. The Montreal engineering firm Genivel-BPR has done the detailed engineering work for the modernization.
The material handling system consists of one carrier per tank-house bay, as well as a series of automated guided carriers that manipulate a cell-load of anodes or two cell-loads of cathodes, and link the tank house with the electrode stripping and dispatching area. The crane-bearing structures had to be reinforced to support the weight of the new equipment and loads in the tank house, and in the electrode dispatching area, which includes the anode preparation equipment and the stripping machines.
The cranes are not just automated; the system chooses the sequence that optimizes production. The operation is controlled by a network of radio-controlled programmable logic controllers (PLCs) in communication with a networked and fully redundant expert system. Communications have to work everywhere; it has been a challenge to ensure that radios transmit around the steel structures. For the sake of safety, the moment any equipment loses communications it just stops.
The anode receiving, cathode stripping and materials handling all operate as one integrated system, so it is possible to trace anodes to the smelter, and to link copper cathodes to an individual tank cell.
“The new technology has been a challenge for the workforce and they’ve met it,” says Otokar Pogacnik, project manager. “Employees have had to upgrade their skills. When equipment doesn’t work now, the electronician gets on his laptop and connects onto the PLC on the equipment to get the diagnostics to fix it.” He adds, “I think the next refinery to be built will use this kind of technology.”
The MCP has been particularly difficult as a retrofit, with up to 300 contractors working in the same space as production; this has required joint planning and smooth communications between the two groups. Safety is a priority: to date there has been only one compensable accident during the three-year project, and a lost-time accident frequency rate of 0.36 per 200,000 person hours, including both employees and contractors.
The MCP has already cut the refinery’s operating costs. It will also increase the capacity, as it will take only 94 tank-house sections to produce the amount of copper that used to be made by 108. Therefore the business can be grown, if it makes sense economically.