| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1987: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1986: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
The purpose of this study was to provide basic information on mineral dressing and utilization of silica sands. The work was done on the silica sand deposits of the Mogami amd Okitama districts, Yamagata Prefecture, Japan.
1. As silica sands decrease in grain size, the Al_2O_3 and Fe_2O_3 contents in silica sands increase. Feldspar is the major source of Al_2O_3 in silica sands. Therefore, it is necessory to remove feldspar in silica sands by undercutting finer grains or flotation for reducing Al_2O_3 content.
2. Quartz in silica sands were mostly derived from volcanic and granitic rocks. Minute glass inclusions are trapped in the quartz of volcanic origin, and crystal and fluid inclusions are trapped in the quartz of granitic origin. Crystal inclusions consist of apatite, biotite, amphibole and zircon. Liquid of fluid inclusions have high concentration of salt. It must be considered the inclusion content for the utilization of silica sands as silica materical ofhigh purity.
3. Ilmenite is the chief constituent of heavy minerals in silica sands. Magnetite, zircon, epidote, biotite, amphibole, pyroxene, anatase, rutile, andalusite and others are accessories. The magnetite/ilmenite ratio is 1/15 to 1/20. Magnetite was mostly altered into the maghemite. These heavy minerals are mostly able to remove from silica sands by gravity separation using table or spiral concentrator. Futheremore, Fe_2O_3 content may be reduced by undercuttin finer grains and magnetic separation.
4. It is necessary to remove the minerals which are hard to melt, such as andalusite and zircon, for the utilization as raw material of plate glass.
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