重液分離による使用クロマグ煉瓦の鉱物組成の研究

平炉に使用された耐火物に関する研究 (第4報)

抄録

A sample of brick was removed from a front wall of a 40-ton basic open-hearth furnace after 114 heat services. This brick was divided into four coloured layer zones, and then these zones were separated to chrome-bearing spinet grain and silicate matrix portions by heavy liquid method. Mineralogical constitution of these spinels and matrices were calculated from the results of these chemical analysis. Density, porosity and thermal expansion ratio were determined at each zone. The results obtained are summarized as follows;
On the chrome-bearing spinel grain; (a) Excess (about 6 mol %) of iron oxide is present in the spinel at the hottest zone, whereas excess (2-7 mol %) of magnesia is present in the spinel at the lower temperature zones. (b) Spinel at the hottest zone is rich in magnetite and ferruginous spinel. (c) The amount of MgO⋅Al₂O₃ decreases markedly at the hottest zone to 7 mol % from 45 mol % at the inner zone.
On the silicate matrix; (a) The amount of matrix increases to a maximum at the region behind the hottest working face, and reaches to about 30% of weight of the original brick. (b) It was determined that the matrix at the hottest zone consists of augite. This conclusion is agreed with our previous report by optical test. (c) The matrix at the lower temperature zone consists of forsterite mainly, in which a little fayalite is dissolved. (d) A little (about 3-5 mol %) MgO⋅Al₂O₃ is dissolved in the matrix.