1、1 英文翻译原文The behaviour of mineral matter in ne coal otation using saline waterSchool of Chemical Engineering, The University of Queensland, St. Lucia, Brisbane, QLD 4072, AustraliaAbstract：In this study the behaviour of mineral matter in the otation of a ne coal sample using saline water was investig
2、ated. For a comparison, de-ionised water was tested in parallel. It was found that saline water increased the recovery of mineral matter while increasing the combustible recovery. By calculating the degree of entrainment in the otation of the coal sample and also the ash after combustion, coupled wi
3、th the froth image analysis and rheology measurements of froth and pulp suspensions, the entrainment and entrapment of mineral matter in coal otation were examined. Compared to de-ionised water, saline water increased the entrainment across the size range and the increase in entrainment was more pro
4、nounced for particles smaller than 38 lm.However, entrapment played a more important role in recovering mineral matter smaller than 38 lm in coal otation using both de-ionised and saline water. Saline water signicantly increased the entrapment through enhancing the aggregation of coal particles.1. I
5、ntroductionCoal mining is an important business in Australia supplying coal to produce 85% Australias electricity. 54% of the coal mined in Australia is also exported, mostly to Eastern Asia. In the last few years there has been a distinct change in the water quality used in coal preparation plants
6、within Australia due to stringent policy on the amount of saline water which a mine can discharge into the local river system. As a result, most coal mines have introduced water re-use as a conventional practice. One of the consequences of increased water re-use is a concomitant increase in the sali
7、nity of water on the sites and subsequently in otation. A number of studies have been conducted to investigate coal otation using saline water. In general, saline water increases combustible recovery compared to fresh water 15. However, these studies have not taken into account the behaviour of mine
8、ral matter in saline water.With the depletion of coal resources, more and more low-grade and difcult coal deposits are being processed and the role of saline water in recovering mineral matter in coal otation becomes important.It is known that the recovery of particles by otation is a function of tr
9、ue otation and mechanical entrainment. In mineral otation the pulp of solid particles in water is conditioned with collectors (a type of surfactants) to render value minerals hydrophobic, while gangue minerals remain hydrophilic. Air is then injected into the pulp to form bubbles that collide with p
10、articles.Hydrophobic particles tend to attach to the bubbles and the bubbleparticle aggregates are then transported to the pulp/froth interface at the top of the pulp and eventually enter the froth launder as the concentrate. This process is called true otation. However, mechanical entrainment of pa
11、rticles taking place when particles are dragged by the interstitial liquid lms between air bubbles always occurs in parallel with true otation and is the primary recovery mechanism for gangue, especially nes 6. Due to its unselective nature and the fact that gangue minerals are generally abundant in
12、 the ore, the recovery by entrainment may have a signicant detrimental effect on the concentrate grade.Entrainment in otation can be considered as a two-step process, including the transfer of the suspended solids in the top of the pulp region just below the pulpfroth interface to the froth phase an
13、d the transfer of the entrained particles in the froth phase to the concentrate 7. The rst step of entrainment is via (i) hydraulic boundary layers surrounding air bubbles 8, (ii) the wades of bubble clusters 9, and (iii) water entrapment by the continuous transport of bubbles into the froth layer 1
14、0. The water ow rate into the froth phase is inversely proportional to the bubble diameter 11. The reduced bubble size in saline water due to the inhibition of bubble coalescence 1214 may promote more water to ow into the froth phase and therefore higher particle entrainment. The presence of the fro
15、th phase in a otation cell provides certain time for the water and the entrained particles to drain back to the pulp phase before the froth enters the concentrate. The transport of gangue minerals in the froth phase is strongly affected by the structure of the froth and the bubble size. Small-bubble
16、d and closely-knit froth is likely to enhance the entrainment of gangue minerals 15.It has been found experimentally that the amount of gangue minerals recovered is intimately related to the amount of water recovered 6. The relationship between the water recovery and gangue recovery is linear over most of the region of interest. When this linear relationship is extrapolated, it produces a zero intercept on the water recovery a
