According to the characteristics of tantalum niobium raw materials, tantalum extraction from tantalum secondary raw materials has attracted great attention. With the gradual reduction of tantalum resources, this kind of recovery becomes increasingly important. At present, the amount of tantalum recovered annually (Ta2O5) accounts for more than 30% of tantalum production. It is a difficult task to extract tantalum from alloys especially superalloys. The composition of hard alloy is complex and the content of niobium tantalum is low. Considering the separation purity, cost and industrial application, tantalum is mostly separated and extracted by chlorination, and also separated and extracted by solvent extraction after acid decomposition. The consumption of tantalum powder for tantalum capacitors accounts for 50%~60% of the total consumption of tantalum powder. For a long time, the recycling is mainly for the waste materials in the production process of tantalum capacitors. For the tantalum capacitors in the waste equipment used in the electronics industry, the organic shell should be decomposed first, then the organic materials and metal components should be separated, and finally the chlorination metallurgy process should be adopted. Tin slag is the most widely used secondary raw material at present, and most of the tin slag is mainly containing tantalum, the treatment of tin slag by continuous leaching to get the enrichment, with the treatment of enrichment by chlorination process, tantalum can be recovered.
Tantalum is a very scattered metal. In nature, tantalum niobium coexists closely, and there is no free or natural tantalum. Due to the scarcity of resources and high price, tantalum has long been less studied. As tantalum plays an increasingly important role in the national economy, the recycling of tantalum materials has attracted extensive attention. At present, tantalum extraction from niobium tantalum concentrate mainly includes two processes: concentrate decomposition and niobium tantalum separation. Concentrate decomposition mainly uses high concentration of hydrofluoric acid. Hydrofluoric acid decomposition not only has serious damage to the test equipment, but also brings great pollution to the environment after leaching waste residue. It is one of the difficult problems that tantalum industry needs to solve to find the fluorine-free tantalum extraction process. While tantalum concentrate is mostly low grade refractory tantalum mine in our country, how to design economical and reasonable route for tantalum extraction process is another urgent tantalum extraction industry in our country. Therefore, research and development of green technology, looking for pollution-free chemical methods, the development of niobium tantalum separation of new technology, is the goal of researchers.
With the development of high efficiency tantalum recovery process from niobium tantalum concentrate, attention should also be paid to tantalum recovery from secondary resources such as superalloy, metallurgical slag and waste tantalum capacitors, so as to achieve comprehensive recovery of tantalum resources. The key factor of tantalum recovery from secondary resources is solubility. It is believed that with the joint efforts of researchers, a major breakthrough in the recovery and utilization of tantalum resources is just around the corner.
