1、1 英文翻译原文Factors affecting electrical comminution performanceEric Wang, Fengnian Shi , Emmy ManlapigThe University of Queensland, Sustainable Minerals Institute, Julius Kruttschnitt Mineral Research Centre, Qld 4068, AustraliaKeywords: High voltage pulses ; Electrical comminution ; Energy efficiency
2、; Numerical simulationABSTRACT:Factors affecting electrical comminution performance were investigated through experimental work and numerical simulations. The effects of feed size, under-sieve classification, incremental breakage and energy input level on particle pre-weakening and mineral liberatio
3、n were tested with six ore samples. Using commercial software, COULOMB 3D, simulation was used to explore the trends between the electrical field distribution/intensity, and the ore particle electrical/mechanical properties. These results were used to interpret the differences in breakage and libera
4、tion for various ores. The results showed that the induced electrical field is strongly dependent on the electrical properties of minerals, the grain size, the location of the conductive minerals in rocks, and the particle shape/orientation. Understanding how the machine-related factors and ore-rela
5、ted factors affect the electrical comminution performance will assist in the machine scale up development.1. Introduction Mechanical size reduction processes in the mineral processing industry are energy intensive. One area of research that could potentially lead to a step change in comminution effi
6、ciency involves applying high voltage pulses to improve the grindability of ores and the liberation of minerals of interest. High voltage pulses have the ability to utilise both the electrical and mechanical properties of the ore to reduce the mechanical strength and improve liberation, thus reducin
7、g the energy required for further breakage. There are a number of reports demonstrating the effectiveness of mineral liberation by high voltage pulses (Andres, 1977, 1994, 2010; Anon, 1986; Andres et al., 2001; Lastra et al., 2003; Cabriet al., 2008). In the pulses liberation process, drill cores or
8、 rocks of 30 mm in size were fragmented into a product in micron size, consuming over 90 kWh/t specific energy (Andres et al., 2001).Compared with a crusher-ball mill circuit to treat the same size of feed ore, the typical energy consumption in the conventional comminution circuit is around 20 kWh/t
9、. Despite the better liberation by the electrical comminution, the energy consumption of over 90 kWh/t is significant to the mineral industry. In the last 4 years, the JKMRC (Julius Kruttschnitt Mineral Research Centre) conducted extensive research on electrical comminution, aiming to find a more en
10、ergy-efficient way to utilise the electrical comminution for the mineral industry. Two major areas using high voltage pulses were investigated: particle pre-weakening and mineral liberation, both focused on improving energy efficiency. The work undertaken by the JKMRC shows that ore particles,treate
11、d by high voltage pulses with low specific energy input (a couple of kWh/t), develop cracks/microcracks and become weaker than untreated particles. Comparison of Bond work indices shows that the treated material may lead to energy savings of up to 24% in the downstream grinding process (Wang et al.,
12、 2011). The JKMRC work also shows that using the same specific energy,minerals of interest in the electrical comminution product are better liberated than those in the conventional comminution product.Therefore, there is a potential to use less energy in electrical comminution to generate a similar
13、degree of mineral liberation. Distribution of the liberated minerals demonstrates that, in the electrical comminution product, a large percentage of the liberated minerals appear in size fractions coarser than 53 lm; while in the mechanical comminution product, the liberated minerals are accumulated
14、 in fine and very fine size fractions. Therefore, there may be potential benefits in recovering the coarse liberated minerals in the electrical comminution product, prior to further grinding (Wang et al., 2012). It was found in the JKMRC work, that the pre-weakening and mineral liberation efficiency
15、 of electrical comminution is variable,and is ore-dependent. Using three models which calculated the distribution of electrical fields in the solids water-system, Andreset al. (1999) showed the concentration of fields at the interface of solids and liquid, for the different mineral components of the
16、 ore aggregates. These results support the idea that the efficiency of high voltage pulses is ore-dependent. In general, however, there is a lack of detailed evidence in the literature on how operational factors and ore-dependent factors affect electrical comminution performance. An experimental program was undertaken to investigate the factors affecting the performance of electrical comminution. These factors can be classified into two groups: the or
