The possibility of successfully using naphthenic acids for extractive extraction of non-ferrous and rare metals has been established by numerous studies. The widespread industrial use of this extractant from non-ferrous metallurgy is hindered by the unavoidable presence of ferric ions in the initial solutions. To remove these ions, it is proposed to use other extractants (for example, fatty acids) or hydrolytic precipitation, which undoubtedly complicates the technological process...