Extraction of rare metals and radionuclides from lean raw materials and soils

Abstract

The content of rare-earth metals (REM) in Kola apatite is about 1%. In the production of concentrates over 8 million tons per year, more than 80 thousand tons of REM are dumped into waste dumps annually, polluting the environment. The main bulk of apatite is processed according to the sulfuric acid scheme to produce extractive phosphoric acids. To extract rare-earth metals from phosphoric acid streams with a capacity of 45 t/h, it is necessary to develop a process lasting several minutes, which does not affect the basic technology and does not require expensive costs of reagents. Crystallization of lanthanide combinations on inoculum directly from production solutions of extractive phosphoric acids meets the requirements. Another pressing problem is the purification of soils contaminated with heavy metals and radionuclides. In laboratory and natural conditions, the purification of soils from 90Sr contamination of the 5th quarter of Vasilievsky Island and Novozybkovsky district of the Bryansk region from 137Cs contamination has been studied. Among different methods of soil decontamination, the most cost-effective and suitable for large soil masses and large territories is soil washing with diluted solutions of mixtures of ammonium and iron (3+) salts. This method can also be used to clean soils from heavy metal contamination in mining regions.