Mineralogical properties of the kaolin mineral included in “oxidized zone” of Iriki kaolin clay deposits, Kagoshima prefecture, were studied in order to clarify the possibility of the utilization as a blending raw material for “White chinaware”. Dispersion and coagulation properties of kaolin clay were also analyzed to find out the optimum condition for removing the ferric and titanium oxides from the kaolin clay by means of a high gradient magnetic separator (HGMS). The experimental results were summarized as follows:
(1) X-ray powder diffraction analysis showed that main mineral compositions of kaolin clay were kaolinite and quartz and minor components were ferric oxide and anatase. EPMA analysis of the are rock revealed that ferric oxide was very fine particles distributed among kaolinite particles and most of anatase had the needle like shape. The minerals of finer particles than 3μm were mostly kaolinite and included a few amount of quartz, ferric oxide and anatase.
(2) Yield and TiO₂ content of the concentrate by HGMS test increased with increasing the matrix loading, however, Fe₂O₃ content did not change with matrix loading. Yield of the concentrate from the clay finer than 3μm increased 20% higher and the quality did not change as compared with the clay finer than 44μm.
(3) HGMS treatments showed that the change of the dispersant concentration did not affect the yield and Fe₂0₃ content of concentrate, but TiO₂ content of concentrate decreased with coagulation of kaolin clay. These phenomena seemed to be explained by taking account of selective coagulation of anatase particles.