Advanced Powder Technology, Vol.21, No.1, 34-40, 2010
A method for dispersing dry nano-sized particles in a liquid using carrier particles
A method for dispersing dry particles in a liquid is described. The method involves coating large carrier particles with fine particles. When two types of particles having different sizes are mixed in dry conditions, the particles adhere to one another, and the large particles become coated with small particles. When the large core particles are coated with a mono-layer of small particles, further agglomeration is inhibited. Because the single small particles generated by the disruption adhere to the core particles, we presumed that, if the small particles that are adhered to large particles could be separated from the large particles by a sonication in a liquid, the dry fine particles could be dispersed in a liquid. The dispersion experiments conducted using spherical silica particles having a count median diameter D-p50 of 74 nm as small particles and spherical glass beads as large particles. In this Situation, the large particles carry the small particles from a dry condition into a liquid. We refer to the large particles as carrier particles. The experiments revealed that the proposed dispersion procedure results in a superior product, compared to sonication only. The effect of carrier size on dispersion performance is also investigated. The findings indicate and an optimum carrier size exists. Observations of the carrier particle surfaces after dry mixing indicate that the optimum condition is the condition at which a mono-layer of Silica particles is formed. (C) 2009 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.