Preliminary Information of Laboratorial Tantalum Recovery and Considerations for a Potential Solution for Conflict Mineral and Wildlife Conservation

Abstract

Tantalum is a rarely occurring transition metal which is chiefly used to manufacture capacitors for electronic appliances such as mobile phones. The demand for tantalum is expected to show an annual growth rate of about 5%; however, tantalum produced in the Democratic Republic of Congo is considered a conflict mineral due to illegal mining which is accelerating the extinction of lowland gorillas. Although tantalum recycling is desirable, the recycling technology has been poorly developed. Phase separation was applied to recover tantalum. It was expected that a copper phase could absorb tantalum, but tantalum was slightly transferred into an iron-rich phase in the Cu-Fe-C system. When ferric oxide was applied as an auxiliary, the tantalum was concentrated as precipitate on the surface of the iron-rich phase. In terms of practical application, a theoretical prediction suggests that the addition of a reductant will make it possible to recover tantalum as a high-purity powder. Since conflict, illicit exploration and hunting (bush-meat trade) have caused a decline in the population of wild animals, it is considered that a feasible tantalum recycling system will be helpful in solving such problems.

Method for Recycling Tantalum from Waste Tantalum Capacitors by Chloride Metallurgy

“…The recycling of Ta is an effective approach to balance the demand for Ta resource and increase resource efficiency in production . In fact, a current estimate shows that nearly 45 million tons of electronic wastes are generated globally per year, and large quantities of waste TCs (WTCs) will be discarded accordingly.…”

Tantalum recycling from waste of electrical and electronic equipment

“…Due to the generation of harmful combustion products of epoxy resin [2][3][4] was not used from burning process. …”

“…Acknowledged practice is mechanical separation of tantalum by breaking and milling [1,2]. Otherwise, it is possible to burn the epoxy resin in 500÷1000 0 C for 1÷5 hours oxidation is also obtained Ta2O5 [2][3][4], which can be reduced most commonly with Na, Mg or Ca [4,5]. Tantalum capacitors can be leached e.g.…”

“…The leaching capacitors by using iron chlorides (FeClx) tantalum chloride is obtained, which is then reduced with Mg [2]. Other methods, such: exfoliation of printed circuit boards containing capacitors [6], tantalum recovery by Cu-Fe-C alloy doped Fe2O3 [3], the electrochemical reduction of dissolved tantalum in molten salt by dysprosium ions [5], are reported.…”

Simple, Rapid, and Environmentally Friendly Method for Selectively Recovering Tantalum by Guanidine-Assisted Precipitation

“…The first method developed to recover Ta from waste solutions, Marignac’s process, is an energy-efficient hydrometallurgical method that uses hydrogen fluoride to form a Ta complex, which is then solvent extracted . Hydrometallurgical processes are not as well-developed as dry processes such as pyrometallurgy, chloride metallurgy, oxidative metallurgy, and solid-phase separation methods. − Improvements in hydrometallurgical processes have focused on process simplification, replacement of hydrogen fluoride with less toxic chemicals, and increasing the product purity. These improvements have been achieved using ion exchange processes, supercritical water, ionic liquids, , and alkaline compounds to form Ta precipitates.…”