The exhibition of the Mining Museum features minerals and chemical compounds from nearly every region of the planet, including some of the most remote locations. However, certain specimens were produced just steps away from the museum halls — in the laboratories of Empress Catherine II Saint Petersburg Mining University. One such example is yttrium oxide, which was donated to the museum by the staff of the Department of General and Physical Chemistry.
Scientists have developed an innovative method of flotation extraction for this and other rare earth metals (REMs) from technogenic waste, particularly metallurgical waste. Approximately 20 patents have already been obtained in this area of research.
Russia accounts for only 1% of global REM production, despite the fact that, according to the Federal Agency for Subsoil Use, the country holds 20% of the world’s total reserves. The relatively low production volume is due to the high dispersion of these elements in the Earth's crust. As a rule, they are extracted as associated components alongside other mineral resources.
However, demand for REMs is increasing. The main consumer is the electronics industry. There is also significant demand in the oil industry (for oil refining catalysts) and in metallurgy, where REMs are used as alloying additives to improve the quality of steel and other metals.
Metallurgical enterprises are therefore among the key stakeholders in the research conducted by scientists at Empress Catherine II Saint Petersburg Mining University. These enterprises can effectively use ion flotation to extract REMs from their own industrial waste. For example, tailings from leaching processes, which contain REMs in low concentrations, can serve as a source.
In addition to reducing dependence on raw material suppliers, the environmental benefit is also of great importance to industry. From an ecological perspective, rare earth elements contained in tailings are hazardous, as they migrate into the soil and subsequently into plants and natural water bodies. Processing through ion flotation enables the nearly complete extraction of REMs, effectively addressing this issue. The national project “Environmental Well-being” includes, among other objectives, efforts to reduce the volume of waste generated by mineral beneficiation processes.
To implement the technology in industry, preliminary semi-industrial studies must be conducted on specific samples of production waste.
«We conducted experiments on model solutions using a laboratory flotation machine. The goal was to extract certain rare earth metals from solutions derived from low-grade technogenic raw materials with the help of detergents, i.e., surfactants. This is a complex physico-chemical process. It requires identifying the optimal flotation conditions for each rare earth element — including temperature, pH balance, and the ratio of reagent ions such as chlorides, nitrates, and sulfates. We used sodium dodecyl sulfate as the detergent» – explained Olga Lobacheva, the author of the development and Associate Professor of the Department of General and Physical Chemistry.
The development has received high recognition at various scientific conferences and exhibitions. Notably, at the 28th International Innovation Exhibition “HI‑TECH” in April 2022, the project “Comprehensive Zero-Waste Technology for Processing Technogenic Waste in the Development of Rare Earth Element Deposits” was awarded a gold medal and a First Degree Diploma in the category “Best Innovative Project (Development) in the Field of: Ecology, Sustainable Natural Resource Management, Waste Sorting, Processing and High-Temperature Disposal, Water Purification.
Research in the field of flotation processes holds a significant place in the scientific agenda of Empress Catherine II Saint Petersburg Mining University. Among recent studies are investigations into the effect of water hardness ions on the floatability of copper-nickel ores, as well as the development of a method to enhance the recovery of platinum group metals from unconventional platinum-containing raw materials. In the area of rare earth metal extraction from waste, one notable development is the technology for the utilization of phosphogypsum dumps.
The university’s scientists are also engaged in the development of flotation equipment. In 2024, the patenting process was completed for the “Smart Flot” flotation complex. A laboratory model has been created and has already won the grand prize at the International Innovation Exhibition “HI-TECH.” Its innovative electrode unit has been successfully tested at one of the Russian mining and beneficiation companies during the flotation of copper ores.
