Effect of feed quantity on breakage degree of ore particles subjected to high voltage pulses

Abstract

Abstract The effect of spatial arrangement of feed sample on the breakage degree of high voltage pulse breakage (HVPB) product was investigated by varying the number of feed particles discharged simultaneously inside a processing vessel. Two kinds of hard porphyry copper ores were treated using the commercial HVPB tester SELFRAG Lab and a custom-made unit respectively. The results indicate that, at given electrode gap and specific energy, the fineness (t10) of HVPB product increases with feed quantity, while the pre-weakening degree (CAb) of HVPB product decreases with feed quantity. A new index of equivalent product fineness (t10e), which reflects the combined effect of t10 and CAb, is employed to represent the overall breakage degree of HVPB product. It is found that the value of t10e has a positive relation with the feed quantity of HVPB tests. The effect of feed quantity on ore behaviour in HVPB is attributed to the influence of particles bed volume on breakdown strength and the negative effect of water gap between ore particles and top electrode. Finally, it is recommended to take feed quantity into consideration in HVPB studies to obtain comparative testing results, and to select the most appropriate breakage degree indexes from t10, CAb and t10e according to research aim. Particularly, electrode gap just filled by feed particles is preferred to optimize the over breakage degree of ore particles.