Recovery of Scandium from Reservoir Silt by Electrical Separation

Pollution prevention and treatment of reservoir silt constitute important environmental protection challenges. Scandium, a key metal, is found in Chinese reservoir silt. However, due to the low scandium content and complex composition of the silt, it is not feasible to directly extract this valuable constituent. With the aid of scanning electron microscopy and polarizing optical microscopy analyses, samples of silt were examined and the different types of minerals containing scandium identified together with their disseminated features. The results reveal that the silt is a high silicon, calcium, magnesium, aluminum vein ore, containing a small amount of iron and titanium complex mineral groups, among which ilmenite and titanaugite are the main minerals containing scandium. The raw silt contains about 6.6 g/t scandium. Based on the silt composition, particle size distribution, and occurrence state of scandium, studies were conducted on preconcentration of scandium oxide from reservoir silt. Based on the results of these experiments, a beneficiation process was developed and validated on pilot scale based on the use of electrical separation for scandium enrichment. A scandium concentrate was obtained with scandium content of 96.23 g/t and recovery of 62.11 wt.%.