The hafnium truth about keeping nuclear energy cool
Alkane Resources Ltd.’s (ASX: ALK | OTCQX: ANLKY) Dubbo project is expected to resolve the shortfall of hafnium production and push forward the technological adoption of the luscious grey metal into new applications that offer great promises to change the way we see energy conservation and power generation.
Hafnium is already well known for imparting unique properties to certain high-temperature superalloys used in the aerospace industry, for example jet engines, allowing them to maintain high strength and stability when operating at very high temperatures. Adding just 1-2% hafnium to nickel cobalt alloys raises operating temperatures from 1400oC to 2000oC, which increases fuel efficiency and reduces emissions associated with better combustion of the fuel.
Hafnium also has increasing uses in oxide form as an electrical insulator in the microelectronics industry. Hafnium’s properties are giving it growing attention in a range of emerging applications in the microelectronics industry. In particular, ferroelectric hafnium oxide has demonstrated potential for a new form of memory storage in microelectronics and for the miniaturization of electronic circuits.
But a new technological consciousness is emerging for the potential for hafnium uses in energy conservation and power generation.
Cooling is a significant end-use of energy globally and a major driver of peak electricity demand. Air conditioning, for example, accounts for nearly fifteen per cent of the primary energy used by buildings in the United States. A passive cooling strategy that cools without any electricity input could therefore have a significant impact on global energy consumption.
A research team from Stanford has developed a coating methodology with hafnium, called Photonic Radiative Cooling, that disperses the heat generated from the inside of the building and reflects the sunlight that would otherwise warm it up. The result is cooler buildings that require less air conditioning. The heart of the Stanford invention is an ultrathin, multilayered material containing hafnium oxide that deals with light, both invisible and visible, in a new way. Its internal structure is tuned to radiate infrared rays at a specific wavelength that’s transparent to the atmosphere (8-13 μm). At just 1.8 microns thick, the material is thinner than the thinnest aluminum foil. Data shows that the coating technology makes the photonic radiative cooler nearly 9 degrees Fahrenheit cooler than the surrounding air during the day.
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Two separate research collaborations have reported advances in the efficiency of thermoelectric materials in converting heat to electricity. A collaboration including researchers from Boston College, MIT, the University of Virginia and Clemson University have achieved a peak ZT (thermoelectric figure of merit) of 0.8 at 700 °C (973 K), in half-Heusler alloys—about 60% higher than the best reported ZT of 0.5 for the materials and possibly good enough for consideration for waste heat recovery in automotive exhaust systems. The study by Yan et al. was published in the ACS journal Nano Letters.
One direct application is the use of Thermoelectric Generators from automotive exhausts (cars and trucks) to convert waste heat into electricity or even new types of solar cells.
While scientists are progressing with novel applications of hafnium, the mining industry has to increase world supply. This is reminiscent of the context that led China to control the bulk of the world’s rare earth elements production.
Arguably the two determining factors for the broad scale adoption of these technologies are going to be price point and supply.
Until recently, hafnium has only ever been extracted from zirconium when high-purity zirconium is required for nuclear energy applications. Production of around 60tpa but new uses for hafnium in a diverse range of innovative applications means there is growing international demand – to the point that demand for hafnium is now outstripping production.
Alkane’s Dubbo Project targets hafnium in hydrous zirconium silicate mineral. To produce high-purity zirconium materials, the Dubbo Project is developing the process to separate hafnium from zirconium. At a planned ore processing rate of one million tonnes per annum and a hafnium recovery rate of 50%, the Dubbo Project could produce up to 200 tonne per year of hafnium oxide. This is more than triple the current world hafnium supply and opens the road to the commercial adoption of exciting technological advancements.
Dr. Luc C. Duchesne is a Speaker and Author with a PhD in Biochemistry. With three decades of scientific and business experience, he has published ... <Read more about Dr. Luc Duchesne>