Studies on the Mikawa Quartzite for Silica Refractories, (III)

In continuing the previous reports (This Journal, 60 [677], 476 (1952); 61 [683] 207 (1953)), in the present paper were reported the results of studies on comparative tests of silica refractories by mixing the Mikawa quartzite with (1) other quartzites: Fujimaki Akashiro quartzite and Akaba quartzite used in the former reports, and (2) some mineralizers used in the previous trials: dolomite, hematite, basic slag and sea-water magnesia. The Mikawa quartzite and other quartzite raw materials above mentioned, were used to make test silica bricks as following: (1) the Mikawa quartzite mainly in the fine grain part, and (2) the Fujimaki Akashiro quartzite and Akaba quartzite in coarse grain part, the latter quartzites being easily heat inversible. To these mixtures were added some parts of mineralizers above mentioned and the cherty part of the Akaba quartzite above used.Many test samples of silica refractories were prepared by these two series of mixtures, and many comparative tests were carried out on variuos physical and thermal properties by discussing on the following points.(1) From the special formation of the Mikawa quartzite and the test results obtained heretofore in the comparative studies on the refractories by graining only the Mikawa quartzite, it cannot be obtained suitable silica brick for steel industry.(2) By using fine grains of the Mikawa quartzite to make matrix part, it can be succeeded to improve the refractoriness, resistance to slag corrosion, softening temperature under load, etc.(3) In this case, it is desirable to use the coarse grain parts of the so-called Akashiro or Aoshiro quartzite, and the Mikawa quartzite cannot be used for mixing over a certain limiting amount.