Abstract <p>When processing ores of rare, nonferrous, and radioactive metals, increasing attention has been given to the two-stage countercurrent leaching method. Compared with single-stage cocurrent leaching, this approach makes it possible to improve the recovery of valuable elements with the same consumption of chemical reagents or, conversely, to reduce reagent consumption while maintaining process efficiency. The two-stage countercurrent leaching method was previously widely applied at uranium mining enterprises in the United States, and recently, greater attention has been paid to its study in the domestic industry. The application of this method is complicated by labor-intensive phase separation and washing operations, such as filtration and thickening; however, with advances in equipment design and the development of effective flocculating additives, these challenges are now being successfully addressed. This paper presents the results of laboratory tests of the two-stage countercurrent leaching of vanadium and other metals from black shale ores. Using this method, the total sulfuric acid consumption was reduced from 18.0 to 12.8%, while the average vanadium recovery increased from 83.0 to 92.5%. It was established that applying a mixture of two flocculants, Praestol 2500 and Praestol 650, with a total consumption of 275 g/t solid after the first leaching stage, resulted in a specific filtration rate of 7.6 t/(m² day). At the second stage, the specific filtration rate reached 8.9 t/(m² day) using the same flocculants at a dosage of 350 g/t solid. These results made it possible to recommend high-performance vacuum filters of the disk and belt types for phase separation after the first and second stages, respectively. Based on the obtained data, a process flow diagram for black shale ore processing was developed, and the initial data for pilot plant design were established.</p>