A much "greener" and harmless leaching method for removing impurity aluminum further from industrial quartz sands by very dilute mixed acids has been presented. With the help of supersonic, the percentage of removal aluminum reached up to 52.5%/53%, that is, 17.4 ppm/17.7 ppm at 30 °C/80 °C, respectively. These results are 4.4/4.7 ppm lower than that supplied by a world famous quartz sands supplier, and the leaching conditions are much milder compared with other comparable methods: the concentration of hydrogen chloride in the mixed acid is only 10% of the others, the leaching temperature is much lower; at the same time, the operating time is only 13-20% of the others, thereby pollution of industrial strong acids and thermo-scattering is reduced substantially.

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Effects of shear rates on average cluster sizes (ACSs) and cluster size distributions (CSDs) in uni-and bi-systems of partly charged superfine nickel particles were investigated by Brownian dynamics, and clustering properties in these systems were compared with those in non-polar systems. The results show that the ACSs in bi-polar systems are larger than those in the non-polar systems. In uni-polar systems the behavior of clustering property differs: at the lower ionic concentration (10%), repulsive force is not strong enough to break clusters, but may greatly weaken them. The clusters are eventually cracked into smaller ones only when concentration of uni-polar charged particles is large enough. In this work, the ionic concentration is 20%. The relationship between ACS and shear rates follows power law in a exponent range of 0.176−0.276. This range is in a good agreement with the range of experimental data, but it is biased towards the lower limit slightly.