Metix slipping devices
South African smelting and technology equipment specialists Metix is a rare beast, spending time actively seeking solutions that will enhance productivity and reduce downtime – usually long before clients have commissioned the upgrades.
Offering the full scope of EPCM services on smelter projects, detailed engineering of furnace-related infrastructure, in-house procurement, cost control systems, site construction, as well as quality assurance and safety, Metix is all about innovation.
According to Metix technology equipment director Jacques Venter, much interest is currently being expressed by international clients and potential clients, even though the industry is in a slowdown. “Based on previous project success, we have had some international contact and are in constant communication with clients across Europe, China and India.”
A key area of interest is in work that Metix has completed for mining giant Lonmin – a primary producer of Platinum Group Metals (PGMs). “Metix was commissioned in 2007 as project manager on an operation that included the rebuilding of an entire furnace for Lonmin in Rustenburg,” says Venter. “While stripping the old furnace, we noticed that the slipping devices, as well as the contact shoes and bus shoes were almost destroyed by corrosion. We suggested to the client that we replace the slipping devices with new ones made from stainless steel, which would provide more resistance to the highly-corrosive environment of the furnace.”
Metix re-engineered the slipping devices that had been originally supplied decades ago. “The design was excellent. We made some minor improvements and alterations and installed the devices with no problems,” says Venter. “The set up procedure was simple and performance has been excellent, with no complaints from our client.” That, in this business, is key to success: The client is content and comfortable that the slipping devices will last around 20 years and greatly reduce safety issues.
Metix decided on stainless steel for the harsh environment as, says Venter, “where SO2 gas comes into contact with water it becomes H2SO3, a very corrosive compound”, creating a hazardous atmosphere that corrodes copper and steel.
While re-engineering the original pressure ring design, Venter also increased the contact pressure between the contact shoe and the casing to prevent arc damage between the two parts, reducing the amount of paste that builds up between the contact shoes and casing.
“Before implementation the contact shoe had to be opened and sandblasted clean, which is now a thing of the past. We redesigned and strengthened the spring that applies pressure and this has reduced paste leaks substantially. It is the first time Metix has done this in a platinum furnace.”
During the Lonmin project, Metix also applied a ceramic coating to all copper components in what is believed to be a first in South Africa. “The ceramic coating is able to withstand temperatures greater than the melting point of copper,” Venter explains. “The ceramic is applied in a similar manner to powder coating and is baked onto the etched-cleaned bare metal. This coating is resistant to sulphur corrosion and thus protects the copper.”
Again, the success of the final result is determined by ‘no complaints from the client’ and Venter says that all indications are that an improvement in production was achieved. “The 9 MVA six-in-line furnace was turning out record production rates on a regular basis after the rebuild.
Another area to which Metix applies its extensive knowledge and passion is that of slipping devices. “Slip-throughs in furnaces can kill people,” says Venter, “which is why many plants are replacing their devices.”
Metix offers a solution where cost is of concern, in a device that is more economical than most but is also failsafe against slip throughs. “The only drawback with this slipping device is that does not allow for back slipping. However, in the platinum industry, backslipping is not required” he says. If backslipping is required by the client then Metix offers its standard slipping device, fully capable of backslipping.
“What makes this design completely failsafe against slip throughs is that both slipping bands are permanently clamped, and either of the bands can hold the full weight of the electrodes. This means that the bands are able to support more than double the electrode mass.”
With over 30 draughtsmen and several design engineers in its employ, Metix has developed patented technology that has caught the eye of international companies. “We have three international patents on our pressure rings, which is now a flagship piece of equipment.” Metix has also applied for patents on furnace roofing and sealings.
Venter says that new technology is attributable to much of Metix’s problem solving capabilities. “We offer an innovative approach and continually look for areas in the industry that can be improved. Some years ago we realised that we needed our own electrode equipment, so we set about designing the best possible solution. The results have been more than pleasing.”
As mines continue to search for ways to maximise the lifespan of their equipment and decrease downtime, Metix continues to innovate. “Every minute of downtime that can be saved contributes to the lowering of production costs,” Venter says. “A client that has equipment that doesn’t give any trouble will be more productive than a competitor.”
Even while many local companies have switched their furnaces off for the time being, Metix is not in the business of waiting for things to improve: “There are new avenues to explore,” Venter notes. “We are looking at the international arena, in particular the Chinese market, which is still looking at furnace expansion. We have had some interest from Norway and other European, companies and we will continue to seek solutions to global mining issues.”
Article by: Ngage