Recycling telecommunications network technology
bifa was engaged by Telekom to examine the recovery processes used, from dismantling the technology to its mechanical preparation through to further processing in metallurgical processes and to identify opportunities for improvements.
Recovery processes and approaches to improvement
bifa's existing material flow models were used to determine the losses and recovery rates for a large number of metals. To this end the actual recovery processes were analysed on site, equipment was dismantled and the structure and chemical composition of printed circuit boards and components were analysed. Based on this, possible ways of achieving improvements were identified, described and evaluated economically.
Installed printed circuit boards
It was found that the processes are already high-quality. Particular attention was then paid to the large numbers of printed circuit boards installed in the network technology. The most important valuable metals are the precious metals: palladium, gold and silver. These are followed by copper, tantalum, tin and aluminium. Analysis of the value losses shows that despite high process quality in the recovery chains through to the metallurgy and despite high recovery rates for the target metals in the metallurgy and their subsequent processes, substantial values of palladium and gold are still lost. These losses are currently practically unavoidable. The same applies to losses of silver and tin.
Germanium, gallium, indium and other metals, which until now are completely lost in the recycling process, are present in such small quantities that recovery is unrealistic. Only the tantalum content in some of the printed circuit boards would allow targeted removal of components containing tantalum (capacitors) to appear economically feasible.
Evaluation of various methods for separating out the tantalum capacitors from the printed circuit boards showed that a robot solution would appear to be interesting, above all due to the large quantities and expected uniformity of the printed boards.
Dismounting test in the KUKA robot laboratory
To analyse the economic feasibility, the tantalum content and accessibility of the capacitors on the printed circuit board types were examined and component removal tests were performed in the KUKA robot laboratory. The tantalum content of the capacitors proved to be very variable; nonetheless the results were promising. However, only printed circuit boards with a sufficiently large number of tantalum capacitors with adequate tantalum content readily accessible to the robot gripper are suitable for the removal of tantalum capacitors. A process and plant concept was then developed and evaluated technically and economically for the robot plant and the processes in its environment. There are good prospects of the process being economically practicable. However, the available quantity of suitable printed circuit boards is still too low.
bifa is therefore currently checking other printed board sources and possibilities of making the robot process even more cost effective.