Purification and stripping of tantalum from organic phase and elimination of emulsification by ultrasound

• A pure tantalum organic phase was obtained by scrubbing 5 mol/L H2SO4 six times.
• The new low-acid extraction process for tantalum is practically feasible.
• 99.6% purity of tantalum oxide can be achieved.
• Ultrasonic technology is a new non-polluting demulsification method.
• The ultrasonic power range of 0.44–0.56 W/ml is appropriate.

The scrubbing of impurities from tantalum-loaded MIBK was investigated using dilute sulfuric acid as scrubbing agent in a cross-current system. The effects of various scrubbing parameters such as sulfuric acid concentration and scrubbing time have been investigated. Stripping studies of tantalum from the scrubbed tantalum-loaded MIBK were carried out using distilled water as stripping agent in a cross-current system. The elimination of emulsification was investigated using ultrasound in the scrubbing and stripping processes. The effect of ultrasonic power on demulsification was studied. After a six-stage cross-current scrubbing with 5 mol/L dilute sulfuric acid and single-stage cross-current stripping, pure tantalum-loaded MIBK can be obtained that yields 99.6% tantalum oxide after precipitation, filtration and roasting. The overall recovery of tantalum was 96.21%. Ultrasound technology can be used for demulsification with the optimal output power range being from 0.44 to 0.56 W/mL.