• Journal of the Mineralogical Society of Korea
• /
• v.15 no.4
• /
• pp.293-304
• /
• 2002

Wet purification process for the selective separation of montmorillonite from Gampo 13 and 35 bentonite ores was studied using physical processes such as ultrasonic scrubbing, decantation and centrifugation. Ultrasonic Scrubbing of Gampo 13 and 35 bentonite ores was revealed excellent result at 7 wt.% of slurry density and was almost finished within 30 minutes in the sample of Gampo 13 and 10 minutes in the sample of Gampo 35, respectively After decantation, approximately 52 wt.% from the bentonite of Gampo 13 and 64wt.% from the bentonite of Gampo 35 were recovered as purified products and the CEC was reached up to 119.4 meq/100 g and 124.5 meq/100 g, respectively. Particle separation by centrifugation showed that most of the impurity minerals such as quartz and feldspar were removed within the condition of 1,000 rpm.

• Journal of the Korean Society for Precision Engineering
• /
• v.26 no.5
• /
• pp.150-156
• /
• 2009

The removal of tiny particles adhered to surfaces is one of the crucial prerequisite for a further increase in IC fabrication, large area displays and for the process in nanotechnology. Various cleaning techniques (wet chemical cleaning, scrubbing, pressurized jets and ultrasonic processes) currently used to clean critical surfaces are limited to removal of micrometer-sized particles. Therefore the removal of sub-micron sized particles from silicon wafers is of great interest. For this purpose various cleaning methods are currently under investigation. In this paper, we report on experiments on the cleaning effect of 100nm sized fluorescence particles on silicon wafer using the plasma shockwave occurred by femtosecond laser. The plasma shockwave is main effect of femtosecond laser cleaning to remove particles. The removal efficiency was dependent on the gap distance between laser focus and surface but in some case surface was damaged by excessive laser intensity. These experiments demonstrate the feasibility of femtosecond laser cleaning using 100nm size fluorescence particles on wafer.