Article by Tim Outteridge of the Materials World Magazine, 02 Nov. 2013
Molybdenum attracted an unusual level of media coverage this summer, concerning a new theory that life on Earth may have begun on Mars and been transported here by meteorite. Molybdenum plays an essential role in creating life, but would have only existed in the required form on Mars at the time that life on Earth began, according to a recent study.
Whatever the reality, molybdenum can play an important role in helping to minimise the impact of man’s activities on Earth. Its unique properties as a metal, as an alloying element and as a constituent of chemical products already contribute to sustainable development in a wide range of applications and technologies.
The inclusion of just a small amount of the material can make a big difference to a product’s performance. When used as an alloying element, molybdenum can increase the strength of steels at normal and elevated temperatures, without sacrificing toughness. It also gives exceptional corrosion resistance to stainless steels and nickel alloys. These property-enhancing effects are often the key to a more sustainable use of materials.
Molybdenum alloyed steel is now making considerable contributions to sustainable building in terms of energy efficiency and resource conservation. The Federal Building in San Francisco, USA, for example, incorporates a computer-controlled sunscreen made from molybdenum-containing Type 316 stainless steel. Combined with natural ventilation, this greatly reduces the need for air conditioning, cutting the building’s energy consumption by two-thirds. The molybdenum in the stainless steel increases its resistance to corrosion from the urban coastal environment and can guarantee a design life of 100 years.
Molybdenum is also making a contribution to the construction of more sustainable buildings through its role in the production of high-strength steel (HSS). Adding more carbon can increase the yield strength of steel, but this can have a detrimental effect on both ductility and weldability. The addition of molybdenum increases yield strength without compromising weldability helps maintain toughness and improves hardenability.
HSS enables stronger and lighter structures than conventional steel, thereby reducing cost and energy in production and transportation. Although CO2 emissions resulting from the production of HSS are slightly higher than those for standard steel, the overall weight savings from using HSS typically lead to significant overall reductions.
In long-span structures, HSS can replace conventional steel. An illustration of this is the roof of the Friends Arena in Stockholm, Sweden, which was constructed using HSS, with only 750kg of molybdenum contained in the higher strength grades. Replacing conventional steel with HSS in the roof reduced total steel consumption by 17% and total costs by 14.5%, while generating a 17% reduction in greenhouse gas emissions.
Solar energy is an important renewable source and, beyond building, molybdenum provides several advantages as a component of the back electrode in new thin-film photovoltaic panels, including withstanding process temperatures up to 650°C and resisting associated high-temperature corrosion. It is deposited using sputtering, where high-energy inert gas plasma ejects atoms from a molybdenum target, producing a high-quality film.
Molybdenum is also being used in hydroelectric installations to create thinner walled, stronger penstocks (large-diameter pipes connecting the dam to the turbine house), enabling higher water pressure to the turbines. It is also found in the gears and shafts of most wind turbines, allowing them to stand up to the incredible stresses that would otherwise render ordinary steel components unserviceable.
In transport, molybdenum-containing HSS is increasingly used for light weighting automotive bodies and chassis. Compared to a conventional car body, HSS can reduce total weight by 100kg, generating fuel savings of 0.1–0.5 litres per 100km.
This raw material also helps to protect the environment by contributing to the reduction of sulfur dioxide emissions. A molybdenum-based chemical compound is an essential component in the catalyst process that removes sulphur from diesel. As an alloy constituent in stainless steels and nickel-based alloys, it plays a major role in preventing life-limiting corrosion in the flue gas desulphurisation units at fossil fuel power plants.
The unique properties of molybdenum are not new, but the performance and environmental advantages they confer on other metals across a number of applications mean it is fast becoming an essential material for sustainable development.
Swissmetal Inc.s´ “Construction & Engineering” contains Molybdenum, which makes it now accessible for private investors to purchase and profit from the increase in demand over the years to come. Click here to contact Swissmetal for a free consultation on procurement & storage of this rare industrial metal.
Story Source: The above story was Published by Materials World Magazine on 02 November, 2013 click the following link for the original article click here