Introduction

The invention presents a sustainable and economical process for the recovery of tantalum from spent electronic components. The process includes comminution, sieving, magnetic separation and electrostatic separation to remove ferromagnetic and non-conductive materials. Next, two leaching cycles are performed: one to remove the manganese dioxide and another to remove the silver. The product obtained is a high purity tantalum, with concentrations around 96%. The process avoids heat treatments and pollutants, offering a advantageous alternative to mining.

Technical features

The present invention concerns a sustainable and economical process (TRL 3) for the recovery of tantalum and its compounds from exhausted electronic components, avoiding the use of high temperature treatments or polluting chemical substances, as in the few recovery processes used so far. The process starts with a comminution, possibly at cryogenic temperatures, followed by sieving and magnetic separation to remove ferromagnetic material, such as iron and nickel, present in the electrodes. A subsequent step involves the electrostatic separation, to eliminate the non-conductive fraction, which mainly comprises polymers charged with glass.
After this initial phase, the material obtained is subjected to two cycles of chemical leaching treatment. The first cycle serves to remove manganese dioxide (MnO2), using an organic reducing agent (ascorbic acid). The second is dedicated to the removal of silver, through a treatment with glycine or thiosulphate.
At the end of the process, a high purity product is obtained, composed of at least 96% tantalum and its compounds.

Possible Applications

The invention can be used to treat:

• Spent tantalum capacitors waste;
• Batches discarded during production.

Advantages

• Low cost and high yield process;
• The use of eco-sustainable and low-toxic reagents;
• It generates non-toxic and no pollutants by-products.