What comes to mind when you hear the word asbestos? A mineral used in the manufacture of insulation or its associated health risks? What about magnesium? And what does magnesium have to do with asbestos?
The waste rock left from mining asbestos is rich in magnesium, and demand for the lightweight metal is growing 6 percent a year. A century of asbestos mining left behind a gigantic mined-out pit and more than 250 million tons of gray waste rock near the town of Asbestos, Quebec. The 1.4 mile long plateau is now being used to help revitalize the mining community by providing hundreds of new jobs.
Magnola, a company owned by Noranda Mining and Metals Company, built a 491.5 million dollar (U.S.) facility just outside of Asbestos. The Magnola plant utilizes a relatively new technology that extracts magnesium via electrolysis from the asbestos waste rock. The electrolysis technique was developed by Magnola at a cost of 45.6 million dollars (U.S.) over a decade, to be used for the first time in the world at Magnolia.
The Magnola plant has the capacity to produce 63,000 tons of magnesium per year, which is 16% of the world’s consumption. The waste mounds near Asbestos contain 24% magnesium, sufficient for the new plant to operate for over 300 years.
Magnesium is used in a variety of areas such as an alloy in aluminum, structural material (mostly high pressure castings), portable tools, sporting goods, and as a de-sulfurant in the ferrous metals industry. Magnesium is also being utilized by automakers to make lighter parts such as air bag canisters, instrument panels, and steering wheels. The lighter material reduces the weight of the vehicle, therefore cutting its fuel consumption and emissions.
What role did Aerovent play?
Magnola needed exhaust fans for their electrolysis building capable of 83,333 CFM each, totalling 2 million CFM. Aerovent supplied them with twenty-four (24) specially designed 72" plenum mounted panel fans with Type W vaneaxial propellers.
More importantly, Magnola was looking for a fan manufacturer that was capable of their stringent design requirements, and that was also capable of performing and duplicating customer witnessed sound and air performance tests.
The first sentence of the specification read, “The fans shall be of the manufacturer’s standard design, with proven and successful service in similar applications.” The rest of the specification was anything but standard, challenging Aerovent engineers every step throughout the design process. Some of the special design requirements included:
- Designed to withstand wind loads of 160 km/hr and heavy snow and ice loads without the use of guide wires.
- Corrosive atmosphere environment (HCL and CL2) design to provide easy maintenance/access of the motor, V-belt drives, and bearings from inside the building.
- Installation and removal of the entire unit through the roof.
- Emergency manual gravity damper opening system accessible from inside the building.
- 100,000 hr. L-10 life bearings, motor and drives isolated from the airstream.
- Sound power level (LwA) not to exceed 86 dB on fan discharge and sound pressure level not to exceed 85 dBA at 1 meter from the fan inlet.
- Customer witnessed air performance testing for two units with the sound testing to be performed at 100% flow rate (no interpolation allowed).
- Two separate coating specifications, paint systems for outdoor exposure of the stack cap, discharge cone, and curb base and indoor exposure covering the fan housing, plenum section and inlet screen/access section.
The physical characteristics of the fans were just as impressive (see illustration below). The fans stood 24 feet tall and weighed 8,000 lbs. each when completely assembled.
Aerovent is proud to be part of this revitalization effort in the town of Asbestos, but one may wonder . . . will they someday call the town Magnesium?