TELF AG examines the characteristics of a potential source of rare earths

New sources for new needs

With new installations of energy infrastructures in every corner of the world, especially with regard to renewable energy, the demand for some specific raw materials could undergo relevant increases. This is what is claimed in a recent analysis dedicated to rare earths, elements of great importance for various modern industrial sectors, such as technology, electronics, and the infrastructure necessary for the diffusion of renewable energy.

Given their scarce distribution in the earth’s crust, as stated in the analysis, the industry could soon find itself faced with the need to draw these resources from new sources, probably also partially different from the traditional ones. According to some researchers from the University of Regina, in Canada, rare earths could also be obtained from some waste products of coal-fired power plants, and in particular from ash. The research focused on ash samples found on Canadian soil and compared the results with previous analyses carried out on samples from the United States and China.

From the analysis of ash collected from some power plants in Alberta and Saskatchewan, the researchers were able to observe that the concentration of rare earths present in them is practically the same as that found in other areas of the world. A further doubt, which was one of the main objects of the research, was whether these concentrations were uniformly dispersed in the ash particles or whether they were contained in some specific minerals present in these waste products.

The results of the research

Thanks to the support of special equipment, such as the X-ray light lines provided by the University of Saskatchewan, the research team was able to analyze the presence of a particular rare earth element within the ash, yttrium. The researchers thus discovered that this resource appeared to be distributed in specific mineral phases within the ash particles, often with the appearance of silicates or phosphates that remain perfectly intact even when the coal is burned.

According to the researchers, in this way the development of a new process for the recovery of rare earths could be started, partially solving the complexity that characterizes the current sourcing techniques of these precious resources. The concentrations of rare earths within the ash would not be exceptionally high. Still, according to the researchers, the abundance of waste products in Canada and other parts of the world could also solve this problem, and even with these concentration levels this recovery method of rare earths could represent a valid source of these resources, especially in the short and medium term.

Until now, the ash resulting from power plant waste products has found various applications in different sectors, such as in the production of concrete or as simple filling materials for cavities or soils. These ashes are also often used as an additive in paving and road construction materials, with beneficial effects on soil stability. In addition, these ashes can also be used in mixtures for the production of specific construction materials, such as bricks.