Investigations on the recovery of recyclable metals from metallic residues
The VDEh-Betriebsforschungsinstitut and the institute for technical mechanics/flow mechanics (TU Clausthal) develop an ultrasonic reactor for the recovery of valuable metals from residues of the steel and metal processing Industry.
Global consumption and the increasing shortage of raw materials require the conservation of resources and the efficient use of raw materials, i.e. the closure of material cycles through the recovery of metallic raw materials. In the hard-metal industry, for example, important raw materials such as titanium, cobalt, tungsten and nickel are used, the recovery of which from production residues or scrap makes economic sense. In hydrometallurgical recovery processes, metals are dissolved in a reactor using a solvent. The reaction can be improved by increasing the dissolution rate by using ultrasonic technology.
In the AiF research project “Ultrasonic Reactor”, the development of an operational ultrasonic leaching reactor for the recovery of valuable metals was experimentally tested in laboratory and pilot plant trials as an example for carbide-containing TiC and WC hard metal scrap (Fig. 1 shows the developed ultrasonic pilot plant acid reactor in the sound isolating enclosure). Furthermore, a flow and reaction model was developed for the reactor concept, which is based on an accelerated chemical dissolution reaction under the influence of ultrasound (Fig. 2 shows a calculated ultrasound field for the pilot plant reactor).
It could be successfully demonstrated that for the innovative process by means of ultrasonic input, an acceleration of the dissolution of lumpy TiC residues is possible up to a factor of approx. 10 (on average 3.6) in the HCl acid solution, depending on the material. With regard to the resolution of lumpy WC residues, the effects of ultrasonic-assisted resolution were low.
Scale-up model studies show that by extending the ultrasonic generation units and optimizing the arrangement of the probes, a further increase in the acceleration of the resolution can be achieved by implementing reactor technology. Economic feasibility studies of two plant concepts for operational applications resulted in amortization periods of the investments of approx. 2-3 years.
The IGF project 18486N “Ultrasonic Reactor” of the Research Association VDEh-Gesellschaft zur Förderung der Eisenforschung mbH – VDEh GmbH, Sohnstr. 65, 40237 Düsseldorf was funded by the AiF within the framework of the Programme for the Promotion of Industrial Community Research (IGF) of the Federal Ministry of Economics and Energy on the basis of a resolution of the Federal Parliament. We would like to take this opportunity to express our sincere thanks. We would also like to thank all the companies involved in the project for their active support.
The final report is deposited in the VDEh library.