A reliable and as independent as possible supply of raw materials is of crucial importance for Europe. Particularly in view of the expected supply bottlenecks, the European Union has defined a list of critical raw materials which are of decisive importance for the development of innovative technologies and products, such as batteries for electric cars, photovoltaic systems or components for wind turbines. One way of counteracting the shortage of raw materials is to extract manganese nodules. These nodules can be found on the seabeds of most oceans and consist of manganese and various metallic elements such as nickel, copper, cobalt, gallium and various rare earths.
The "Blue Nodules" research project (Proposal Number: 688975), funded by the EU under the "Horizon 2020" programme, is developing a system for extracting manganese nodules in the deep sea. The project is carried out by an international consortium of 14 partners from 9 EU countries. The development of the system focuses on the environmentally friendly extraction of manganese nodules. The influence on the local ecosystem should be kept as small as possible. The extraction of manganese nodules should continue to be carried out with a minimum use of energy. The separation of manganese nodules and overburden prior to extraction to the sea surface is of decisive importance.
The Institute for Advanced Mining Technologies (AMT) has already developed a concept for characterizing the material flow using acoustic emission technology. Acoustic emission sensors have so far been used, for example, in the condition monitoring of pressure vessels and bridges. In initial preliminary tests at the AMT Institute, the physical phenomenon of acoustic emissions has already been successfully used for material flow characterization of bulk material. The AE signals recorded during transport and impact processes are evaluated with regard to characteristic parameters. Characteristic values are calculated and compared with already recorded characteristic values from previous reference measurements. The aim here is to determine differences and thus characteristic parameters for different materials. In the framework of the Blue Nodule project, this concept has now been adapted for use in the deep sea in order to characterize the material flow of manganese nodules and overburden.