INVESTIGATION OF RARE AND RARE-EARTH ELEMENTS LEACHING PROCESSES FROM THE WEATHERING CRUST ORES OF THE KUNDYBAY DEPOSIT

The weathering crust ore of the Kundybay deposit is a hard-enriched ore that contains such minerals as cherchite, bastnesite, kaolinite, etc., which are embedded in the matrix structure of other silicate rocks. These minerals contain rare earth (RE) and rare earth elements (REE). The multi-component structure and dense packing of minerals in the aluminosilicate matrix of the ore make it difficult to be blocking out. Determination of the optimal ore blocking method in order to extract RE and REE is an urgent task for today. The purpose of this work is to develop an effective method of leaching RE, REE and "white soot" from the weathering crust ores of the Kundybay deposit. Methods. Processing with soluble ammonium, magnesium and aluminium salts will allow estimation of the state of RE and REE in the ore. The indicator of RE and REE blocking out during leaching with sodium hydroxide is the transfer of silica into solution, due to which RE and REE form their own hydroxides, which can be subsequently transferred into solution by acid treatment. Acid leaching with sodium pyrosulfite, hydrofluoric acid and sulfuric acid will allow the RE and REE to be immediately transferred into solution. Results and Discussion. The main characteristics of the Kundybay deposit weathering crust ore were determined, such as: silica content, moisture content, base metals, RE and REE. Conclusion. The degree of extraction of RE and REE by soluble salts of ammonium, magnesium and aluminium did not exceed 2%, which indicates the existence of RE and REE in the form of their own minerals. Leaching with sodium hydroxide showed low recovery of silica, with RE and REE remaining in a difficult-torecover form. Leaching with a mixture of sodium pyrosulfite, hydrofluoric and sulfuric acids is a promising method for RE and REE recovery due to the complex effect of the components of this mixture.