Kazuhiko Jinnai

Zeta potential measurement of muscovite mica basal plane-aqueous solution interface by means of plane interface technique

Abstract The zeta potentials of muscovite mica basal plane were investigated by means of the plane interface technique as a function of pH in the presence of 0.001 M KCl, compared with those of fused silica. For the plane interface technique, the negative zeta potentials of a large muscovite mica sheet, i.e., the mica basal plane, were uniformly higher in magnitude than those of a large silica plate over the pH range from 2 to 11, whereas the zeta potentials of the mica basal plane were markedly dependent on pH in the pH range of 3 to 6. In the pH range of 2 to 3, the zeta potenteials of the mica basal plane showed remarkably negative values of −80 to −60 mV and became more insensitive to the reduction in pH. In particular, we could not observe the presence of an isoelectric point (iep) of the mica basal plane, which has never been encountered normally in the case of pure oxides. For comparison, the electrophoresis measurements were made for both mica and silica particles. The negative mobility zeta potentials of mica particles were smaller in magnitude than those of fused silica particles in the pH range of 3 to 11 even though the positively charged alumina-type sites on the mica particles were neutralized by sodium dodecyl benzene sulfonate (SDBS). This result was quite the reverse of the trend obtained from the plane interface technique. However, the variation in flotation recovery of the muscovite mica with dodecyl ammonium chloride (DAC) as a collector at pH 3 was very consistent with that of crystalline quartz (ζ ∼ −65 mV) with dodecyl trimethyl ammonium bromide (DTAB) at pH 7.4. This observation provided justification for the remarkably negative zeta potential (∼ −75 mV) of the mica basal plane obtained from the plane interface technique at pH 3.

Synthesis of expandable fluorine mica from talc

Expandable fluorine micas were synthesized using talc and Na2SiF6 at 800°C for 2 hours in air, nitrogen, argon, and under vacuum. Gaseous SiF4, generated from Na2SiF6, and the resultant amorphous sodium silicofluoride formed during the reaction between talc and Na2SiF6 below 900°C are taking active part in the formation of expandable micas because the intensity of the 12.5 Å reflection of expandable micas decreases as the gas flow increases in the furnace. Expandable micas seem to be formed by the transformation from talc taking place without the entire disruption of the original atomic arrangement. This takes place with the loss of one Mg2+ from an octahedral site and by the intercalation of every two Na+ into the interlayer site of talc. Infrared absorption and thermal analyses show that expandable micas include a small amount of OH− in their structures.

Analytical evaluation of locked cycle flotation tests

Abstract A locked cycle test is one of the testing methods used to develop the optimum mineral recovery process. In order to understand the behavior of locked cycle tests, material balance equations are set up at the n th cycle of locked cycle tests consisting of three and four stages, called rougher, scavenger, cleaner and recleaner, and analytical solutions are obtained. From the analytical solutions, it becomes clear that the iteration number of the locked cycle tests required to reach a steady state depends on the flotation rate constant, the flotation time, the arrangement of the flotation stages and the total mass of recycled middlings which are discharged from the n th cycle of the locked cycle tests and fed into the subsequent ( n + 1)th cycle. In addition, flotation characteristics obtained from analytical solutions of a locked cycle test are compared with those of a continuous flotation circuit on the assumption that each flotation stage is composed of the same number of perfectly stirred cells of the same volume. As a result, it is found that good agreement between the theoretical locked cycle test and continuous flotation results is obtained when the number of cells in each stage is large.

Properties of the Pyroclastic Deposit in Kusu, Oita Prefecture for a Raw Material of the Micro Shirasu-balloons.

The pyroclastic deposit in Kusu formation in Kusu, Oita prefecture was surveyed. Average particle sizes in the collected five areas range from 11 to 150μm. Particle size of the upper level in the pyloclastic deposit was smaller than that of the lower level. Main constituents of minerals in the samples were volcanic glass, feldspar, hornblende and quartz. Two kinds of upper level samples were separated by elutriation method to three size fractions of 5-10μm (S), 10-20μm (M) and 20-45μm (L), of average particle diameters of 9μm, 18.5μm, 28μm, respectively. Particle densities of samples were 2.35 g/cm3 in average. The separated samples were heat-foamed for a few seconds at 1,000 °C in a furnace that was designed for the heat-treatment of small size particles. Expanding ratios of the partially foamed S samples after heat treatments were determined to be from 1.11 to 1.21, and the particle densities from 1.95 to 2.12 g/cm3. Expanding ratios of the foamed L samples ranged from 2.65 to 2.66, and the particle densities from 0.88 to 0.89 g/cm3. Floating part in water of the foamed S samples was smaller in mass-ratio of less than 2 %；however, that of the foamed L samples was relatively large, from 56.8 % to 61.5 %. The shapes of the foamed particles were almost spherical.

The effect of sericite property on clay flotation of amakusa pottery stones. Study on removal of feldspar from amakusa pottery stone by flotation. (3rd Report).

The effect of sericite property on clay flotation of Amakusa pottery stones with Coco amine hydrochloride (COAC) as a collector was examined for the samples collected from different quarries. The clay minerals of Amakusa pottery stones are mainly sericite and a little amount of kaolinite. Results obtained are summarized as follows.1) When sericite in Amakusa pottery stones was treated with dodecylamine hydrochloride (DAC) which is the main component of the collector, dodecylamine-sericite complex was formed in the interlayers of sericite. The formation ratio of dodecylamine-sericite complex increased with the increase of the ratio of swelling layers (montmorillonite) in sericite.2) The flotation recovery of clay minerals was low, since the amount of COAC adsorption on the external surface of clay minerals was little due to the large amount of COAC adsorption in the interlayers of sericite with the swelling layers.3) With increasing the ratio of the swelling layers in sericite, the amount of DAC adsorption increased and the flotation recovery of clay minerals decreased.

On the Separation Tests of the Weathered Granite in Kyuragi-machi, Saga-ken

This time the author has performed some separation tests of the weathered muscovitegranite which occurs abundantly in Amakawa, Kyuragi-machi, Higashimatsuura-gun, Saga-ken.As a result of the tests, the author has found that it is possible to separate the present material easily, especially without flotation, into Silica sand, Feldspar and Clay only through attrition, differential grinding and sizing. And according to this study, a mineral processing plant for the weathered granite, which treats 1000-1500 tons a month in feed, has been constructed in the above mentioned place. The outline of the flow sheet is introduced in this report.Additionally, some results of flotation tests have been reported here.