This study investigates how changes in the surface properties of three representative sul de minerals (galena, sphalerite and chalcopyrite) affect their oatability in the presence of an oxidizing agent (H 2 O 2 ). Tests were conducted at four molar ratios of H 2 O 2 :mineral (0, 0.5, 1.0, and 2.0). To better capture the effect of surface oxidation, the tests were conducted at both acid and basic conditions (i.e., pH = 3 and 10). In all surface property and oatability evaluations, the pH and Eh were equilibrated. The surface properties were evaluated by X-ray diffraction, Fourier transform infrared spectroscopy, zeta potential measurements and contact angle analyses. The oatability was evaluated by a micro otation method. At the acidic initial pH, galena most sensitively reacted with H 2 O 2 , followed by chalcopyrite and sphalerite, whereas at pH 10, the reactivity differences were insigni cant. H 2 O 2 addition changed the sul de species (initially present on the mineral surface) to sulfate or hydroxyl species, and decreased the mineral oatability. To investigate the surface property that mainly reduced the mineral oatability in the presence of H 2 O 2 , we measured the zeta potentials and contact angles, which are closely associated with the electrostatic and hydrophobic forces, respectively. The oatability depended on the contact angle after the H 2 O 2 addition, implying that the oatability was mainly reduced through oxidation reactions, which increased the hydrophilicity of the mineral surface.

In this study, barrier ribs of plasma display panel were formed via capillary molding process. Various types of working molds were prepared by casting liquid polydimethylsiloxane on master molds that were produced from a photoresist film. A thermosetting paste was filled into the cavities of working molds by means of capillary action of paste and was cured prior to removing the molds. The effects of solid loading in the paste, prefiring temperature and type of barrier ribs on the sintering shrinkage were investigated. It was demonstrated that various types of barrier ribs could be produced successfully by sintering the ribs formed by the molding process.

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Nickel oxide ores are composed of two kinds of minerals; one is saprolite that is processed by smelting to obtain nickel products, and the other is limonite that is used in hydrometallugical processes. It is not efficient economically to process the mixture of limonite and saprolite, so the processes to saparate the ore mixture should be developed. In the present study, the mixture was separated by dry-classification after liberationg using grindability difference between limonite and saprolite. Consequently, it is possible to obtain the limonite with less than 10% of Mg+Si contents, which could be treated by hydrometallurgical processes, when the limonite contain less than 30% of saprolite.

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