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Ultra-High Performance Fibre-Reinforced Concrete (UHPFRC) such as LafargeHolcim Ductal® is a new concrete product that incorporates large amounts of fine metal fibres, and is designed to have multiple advantages over traditional concrete products. These fibres, while providing additional strength, represent a new recycling challenge as they may block or increase wear of conventional mechanical apparatus, or be broken during processing rendering them unusable. High voltage electric-pulse fragmentation (EPF) systems such as those produced by SELFRAG AG use repeated electric discharges to selectively fragment composite materials along phase boundaries, overcoming compressive strength and preventing damage to metallic fibres. Initial tests in a laboratory scale system at a range of specific energy levels up to 60 kWh/t showed that Ductal® sample with a compressive strength of 170 MPa was amenable to EPF with good recovery rate of the steel fibres, which were fully liberated in the 0/2 mm product size fraction. Upscaled tests were performed on two Ductal® samples with compressive strengths of 170 and 210 MPa respectively using the 'Pre-Weakening Test Station' (PWTS), a continuous EPF system. Tests with specific energy levels up to 27 kWh/t showed similar results for both Ductal® samples: fibre liberation correlates with increasing specific energy input up to a plateau at about 13 kWh/t where increased energy produces little to no additional breakage. About 60% of fibres were recovered after just one treatment step performed at 13.4 kWh/t. These promising results obtained at pilot-scale indicate that this technology is suitable for UHPFRC recycling and fibre recovery, and that scaling-up the process to a commercial level is technically feasible.

Two approaches for the use of the Electric Pulse Fragmentation (EPF) in the beneficiation of a lowgrade cassiterite schist ore were investigated through pilot-scale tests performed on samples of about 270 kg. The first approach used EPF treatment for pre-concentration while in the second approach the EPF technology was mostly used for crushing. Comparison with the use of conventional crushers was performed.Results showed that the EPF pre-treatment led to a decrease of the Bond rod mill work index while the Bond ball mill work index remained unchanged. This means that the decrease in the energy consumption requested to grind the material down to 1.18 mm (closing screen of the Bond rod mill work index) is no longer noticeable with additional grinding stage to reach a size down to 106 µ m (closing screen of the Bond ball mill work index).This may be due to the fracture network generated during EPF being consumed immediately in the ⁎ Corresponding author.i The corrections made in this section will be reviewed and approved by journal production editor. subsequent comminution step. Alternatively, it may be that the Bond ball mill work index is not appropriate for exhibiting the weakening effect of the EPF technology when the mineral liberation size is coarser than the closing screen size used for the test. Concentration tests performed on the sample treated with the first approach for EPF showed no marked change in separation performance. However, a higher concentrate grade was obtained when using this EPF pretreatment, indicating a probable potential for improvement.

Electric Pulse Fragmentation (EPF) is an innovative technology that uses High-Voltage Pulsed Power (HVPP) for the selective comminution of a material. This paper aims to compare a beneficiation flowsheet including an EPF treatment in the comminution circuit to a conventional pathway where the EPF step was replaced by a series of jaw crushers. Tests were performed on a skarn ore containing scheelite as the main mineral of interest. This ore is characterized by a finegrained mineralogy and represents a challenge to conventional comminution processing, requiring fine grinding to liberate the valuable minerals. Fine grinding has high energy requirements and Kathy Bru Formal analysis Investigation Methodology Conceptualization a,⁎

Abstract. Three disaggregation methods, i.e. Calgon, acetic acid and electric pulse fragmentation (EPF), have been applied to a range of heavily lithified, carbonate-rich sedimentary rock samples of Paleogene age. Samples are predominantly from the carbonate-rich, shallow water domain (<250 m palaeo-water depth) of Tanzania, Malta and the United Arab Emirates (Paleogene Tethys Ocean). The effectiveness and efficiency of each method has been compared, in addition to the preservation of the resultant liberated microfossil material (primarily larger foraminifera; LF). Of the three methods, the most efficient and effective was EPF, which liberated the largest number of LF in a very short processing time and resulted in the best preservation. Samples with calcitic, silicic, and clay matrices and cements were successfully disaggregated using EPF. In this study, recovered microfossils were largely >500 µm, suggesting this technique may be more appropriate for liberating larger microfossils (e.g. LFs); however, we discuss nuances to the method that would allow for more effective recovery of smaller microfossil specimens. The more traditional acetic acid method was also able to disaggregate a number of the samples; however, preservation of the LF was compromised. We suggest a best-practice methodology for implementing EPF in micropalaeontological studies.