Evaluation of the Degree of Dispersion and Coagulation of Silica Nano-particles by Means of Interactive Force Apparatus
This paper describes the evaluation method of dispersion and coagulation of silica nano-particles by means of interactive force apparatus. The apparatus measures the size of fine particles in aqueous solution or organic solvent of high concentration and/or low optical transparency. Other conventional apparatus for size measurements (such as, apparatus utilizing dynamic light scattering) are difficult to measure the size of particles in such conditions accurately, due to multi-scattering of light in the sample solution or solvent. The apparatus measures the interactive force between two surfaces, i.e. the gold-coated glass hemisphere and the brass flat plate, (which is fixed at the bottom of the sample cell). The apparatus has three parts,i.e. main part (which consists of electric balance,hemisphere and flat plate), control part (i.e. personal computer, piezo-stage controller and voltage supplier), and detecting part (i.e. multi-meter and oscilloscope).During the measurement, electric field is applied between the hemisphere and flat plate, and thus dielectric particles are arranged toward the direction of electric field in the area between two plates.When the two plates are close to each other, two different forces (i.e. repulsive force and attractive force) will alternately act on particles due to the structure change of the particles. The repulsive force occurs when the structure of particles is stretched by compressive force; whereas the attractive force occurs when the aggregate structure is broken. The cycle of the repulsive and attractive forces is a primary size of particle or size of aggregate, which depends on the degree of agglomeration.The measured size of particles, which is varied depending on their degree of dispersion and coagulation, determined the characteristics of the silica particles. In this research work, the effect of size and concentration of particles in aqueous solution on the degree of dispersion and coagulation of the silica particles were investigated. Spherical silica particles were selected for this investigation due to their variety of size. This apparatus can be used to evaluate the degree of dispersion and coagulation of other nano-particles in various solvents in many process industries.
Dispersion and coagulation Silica nano-particle Interactive force apparatus Size
A.Otsuki G. Dodbiba J.Sadaki T. Fujita
Department of Resources and Environmental Engineering, School of Creative Science and Engineering,Fa Department of Geosystem Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo,
国际会议
XXIV International Mineral Processing Congress(第24届国际矿物加工大会)
北京
英文
2198-2207
2008-09-24（万方平台首次上网日期，不代表论文的发表时间）