T. Leißner

Milling Result Prediction

Fine grained ore can only be exploited with finer milling, which results in additional milling costs. The ability to infer the optimal milling parameters and corresponding grades of recovery from microstructural information allows optimal extraction and predicting processing costs and final recovery. The MLA (Mineral Liberation Analyzer) allows the 2D size of grains in the ore to be quantified. We have developed a method to predict the 3D liberation of the value mineral in the ore from a combination of milling experiments and MLA images.

High voltage fragmentation of composites from secondary raw materials – Potential and limitations

The comminution of composites for liberation of valuable components is a costly and energy-intensive process within the recycling of spent products. It therefore is continuously studied and optimized. In addition to conventional mechanical comminution innovative new principles for size reduction have been developed. One is the use of high voltage (HV) pulses, which is known to be a technology selectively liberating along phase boundaries. This technology offers the advantage of targeted liberation, preventing overgrinding of the material and thus improving the overall processing as well as product quality. In this study, the high voltage fragmentation of three different non-brittle composites (galvanized plastics, carbon fibre composites, electrode foils from Li-ion batteries) was investigated. The influence of pulse rate, number of pulses and filling level on the liberation and efficiency of comminution is discussed. Using the guideline VDI 2225 HV, fragmentation is compared to conventional mechanical comminution with respect to numerous criteria such as cost, throughput, energy consumption, availability and scalability. It was found that at current state of development, HV fragmentation cannot compete with mechanical comminution beyond laboratory scale.