High capacity furnace and smelting plant specialist Tenova Pyromet has been contracted to undertake the basic engineering and supply of a platinum-group metal (PGM) smelting furnace, feed system and off gas handling plant to platinum mining company Northam Platinum’s Thabazimbi smelter.
Awarded in March this year, the contract requires Tenova Pyromet to design, supply and commission the smelter. With basic engineering already in progress, construction is scheduled to begin in the third quarter of this year.
In addition, Tenova Pyromet will independently conceive the methods of building the furnace and all associated civil works, infrastructure and services for the smelter.
The technical solution will incorporate components produced by Tenova Pyromet including electrodes and copper cooling elements and the off gas handling and furnace controller.
The furnace will tap into the existing tapping bay and will be housed in a building connected to the existing tapping bay building.
A distinctive feature of the design is that it will give Northam the flexibility to operate the furnace either as a submerged arc operation or brush arc operation.
The transformer will feature a wide operating band to ensure excellent performance even under the higher electrical current requirement of brush arc operation.
The roof will be able to withstand a range of heat loads acting on it, from the lower range of submerged arc operation to the very high heat loads resulting from exposure to the open arc operation when running in brush arc mode. Similarly, the shell and taphole are also being designed to withstand the temperature and heat-load fluctuations as a result of the different operating modes.
Sales and marketing general manager Andre Esterhuizen explains that Tenova Pyromet has recently designed a complete furnace cooling system, based on Tenova Pyromet’s plate coolers, for Northam’s existing 15 MW furnace. These were the first Tenova Pyromet copper cooling elements to be installed on a six-in-line furnace.
Tenova Pyromet plate coolers are also being applied in the new circular PGM furnace. These coolers, which can be variously configured to provide different degrees of cooling, offer patented safety features to improve the lifetime of the equipment and prevent burn-throughs, in addition to limiting damage caused by leaks.
Seamless Switch
Meanwhile, in March this year, Tenova Pyromet announced that the two 33 MVA ferromanganese and silicomanganese furnaces, which were switched-in during June 2014 by metal and alloy company Sarda Metals & Alloys with the support of Tenova Pyromet, have consistently met their guaranteed operating parameters since then.
A team of six Tenova Pyromet engineers and process specialists worked in close collaboration with Sarda’s production team throughout the switch-in process, which involved reconfirming the cold commissioning status of the two furnaces by checking the functionality of the equipment and all the alarm and trip set points, followed by the warmup procedure until the switch-in milestone was reached.
Once the furnace production was stabilised, the Tenova Pyromet-supplied automatic furnace controller was commissioned and ramped-up to full production.
These furnaces are part of a greenfield development near Visakhapatnam, India, for which Tenova Pyromet provided the furnace technology package, together with the basic engineering package for the main process plant, following the award of the contract in 2010.
The two furnaces, operating on ferromanganese and silicomanganese respectively, were designed based on an optimised two-step process to handle the feed of a blend of lower and higher grade manganese ores.
The furnaces are equipped with Tenova Pyromet electrode columns, which offer robust operational availability and power efficiency.
Tenova Pyromet asserts that its AutoFurn technology keeps the furnace running as effectively as possible, by maintaining the required furnace power and electrode resistances or currents. Providing an additional level of automation above the typically-used supervisory control and data acquisition and programmable logic controller, AutoFurn results in considerable increases in plant productivity.
The furnaces’ raw materials feed system uses the Tenova Pyromet developed rotary conveyor. Rotating both clockwise and anti-clockwise, the rotary conveyor reduces lag time between charging of each feed-bin.
In carrying out the project and assisting with the cold and hot commissioning, Tenova Pyromet drew on its vast furnace design and operational plant experience, says Tenova Pyromet project manager Henk van der Bijl, adding that the switch-in was seamless and the successful first tap on the furnace was achieved within five days.
“The support we provided Sarda is typical of our approach to our projects to support our installations throughout their life cycle, through commissioning, switch-in and ramp-up, to comprehensive aftermarket support through our client support services.”
Following cold-commissioning, Sarda director of international business, Manish Sarda, stated: “The flexible and interactive way they execute projects made Tenova Pyromet the ideal technology partner for this strategic venture.”