Search

The microflotation of three single minerals, mixed coal–kaolinite and mixed coal–montmorillonite were examined to study the effects of clay and calcium ions on coal flotation. The results show that the ash content of flotation concentrate increases by 3% in the presence of clay minerals, and the ash content would further increase by 3% in co-presence of clay minerals and high concentration of Ca2+. Scanning electron microscope (SEM) images and elemental spectrum analysis indicate that fine clay particles that coat on the coal surface, which is called slime coating, can affect the coal flotation. The slime coating would be induced much more easily in the presence of Ca2+. Keywords: Microflotation, Clay, Calcium ions, Slime coating

Qianjiaying coke coal slime is extremely difficult to float. Conventional flotation process leads to a massive waste of high quality coal. In this paper, raw coal slime and rough separation concentrate are grinded to improve separation effect. Coal slime grinded directly through rough-cleaning process can get concentrate rate of 52.87% and concentrate ash of 11.27%. In the rough concentrate grinding process, concentrate ash drops to 10.74%, when the concentrate accumulation rate reaches up to 55.53%. Compared with the coal slime direct floatation, the concentrate rate was enhanced by 4.66%, and the ash was decreased by 1.02%. Besides, in the regrinding of middlings flotation, the concentrate rate reaches as high as 68.35% and ash rate is only 11.51%, the production efficiency is greatly improved.

Mineral processing plant design curriculum is innovated ceaselessly so as to improve the education quality and to bring students up the engineering diathesis and design competence through the courses, teaching material, experiment, practice in plants, and scientific research. The computer multimedia technic plays a important role in the curriculum innovating. In practice, a serial research, named APPLYING COMPUTER MULTIMEDIA TO A SET OF TEACHING LINKS is carried out. The computer multimedia is applied to compiling the teaching material, classroom teaching, classroom-work, practice after classroom, graduation project and second classroom, which have made great progress.

A broad band polarization-independent reflector working in the telecommunication C+L band is proposed using the guided mode resonance effect of a periodic surface relief element deposited by a layer of silicon medium. It is shown that this structure can provide high reflection (R > 99.5%) and wide angular bandwidth (θ ≈ 20°, R > 98%) for both TE and TM polarizations over a wide spectrum band 1.5 μm~1.6 μm. Furthermore, it is found by rigorous coupled wave analysis that the polarization-independent reflector proposed here is tolerant of a deviation of grating thickness, which makes it very easy to fabricate in experiments.