Uses for Coal Fly Ash (CFA)
While the majority of Coal Fly Ash (CFA) is comprised of carbon, silicon, iron, aluminum, calcium, magnesium, sodium, and potassium, approximately 1% is comprised of high-value metals – REE.
Rare Earth Elements (those in lanthanide group along with scandium and yttrium) and strategic metals are increasing vital to our economy and our lives. Many new inventions and improved processes would not be possible without one or more of these key elements. For instance, Gallium Arsenide multi-junction photovoltaics (Gallium, Arsenic, Germanium, Indium, and Phosphorous) have the highest solar power conversion efficiencies reported to date. Due to the high cost of these materials, this technology has been relegated to space applications, like the Mars Rover project. Even though GaAs/Ge/GaInP2 solar cells offer twice efficiency of multicrystalline Silicon solar cells and five times amorphous silicon, they are not cost competitive to gain widespread use. As a result, domestic products often utilize a an 8% efficient amorphous silicon cell instead of the superior 41% efficient GaAs/Ge/GaInP2 cell.
To cite another example, according to a December 2009 New York Times article, dysprosium and terbium have emerged as the miracle ingredients of green energy products. Even small quantities of dysprosium can make magnets in electric motors lighter by 90 percent, while terbium can help cut the electricity usage of lights by 80 percent. Dysprosium prices have increased sevenfold since 2003, to $53 a pound. Terbium prices quadrupled from 2003 to 2008, peaking at $407 a pound, before slumping in the global economic crisis.
Some of the most common uses are described below:
Cerium is the most abundant of the “rare earths.” It is found in automobile catalytic converters and other pollution control equipment. Cerium helps to reduce sulfur oxide emissions. Cerium is also added to diesel fuel to help it burn better and is used to make optical glass.
Neodymium is used in magnets to make the magnetic field incredibly strong. Cell phones, computers and audio speakers would not exist without neodymium magnets.
Holmium has the greatest magnetic strength of any element, and is used in medical and dental lasers and nuclear control rods. It is also a colorant for glass.
Thulium is one of the rarest and most expensive of the “rare earth” metals. It has unique properties that make it ideal for laser-based surgical tools.
Yttrium is primarily utilized to make red phosphors for use in red LED’s and superconductors.
Europium is a key ingredient in certain types of lasers and is a part of the chemical process to screen for Down’s Syndrome.
Erbium is a silvery white metal created for use in photographic filters and as a coloring agent in cheap sunglasses and jewelry. It is also a key element in optical amplifiers widely used in fiber-optic communications systems.
Dampening enthusiasm for this, however, is a looming shortage – even unavailability – of rare earths. The last mine in the United States to extract rare earths closed in 2006. This leaves China as the near exclusive source (96% of world production) of these vital elements, but China has announced significant reductions in its exports to preserve these elements for its own use and for strategic military purposes. There are reports the China may cease entirely the export of the rarest of these materials.
The TWENTY FIVE METALS model creates an American alternative that ensures the availability of all of these elements and an assured supply will substantially promote the development of new technologies. Translating this finding into today’s prices concludes that the extracted value per ton is over $1000.