THE PHYSICOCHEMICAL INVESTIGATION OF THE ZHURAVLINY LOG KAOLIN. PART 1

Abstract

The considerable portion of kaolin used in Russia was imported from Ukraine. There is urgent necessity to assume the measures for the import substitution in consideration of the presence of suitable deposits. The Zhuravliny Log kaolin deposit (Chelyabinsky district, Russia) is the largest one (more than sixty million tons of assured resources of the primary kaolin) in Russia. The chem-ical and phase composition of the concentrated kaolin was determined. The SiO2/Al2O3ratio made 1.30. The free quartz quantity was equal to 4.4%. CaO and mica were not revealed. Kaolin powders were fine-dispersed (mainly up to 2 μm). In his paper, the thermal behavior of this kaolin was studied by the complex thermal analysis, X-ray diffractometry, and Fourier transform infrared spectroscopy. It was shown that the dehydroxylation occurred at appr. 500 °С. Further, at 910 °Сmetakaolinite probably turned into silica spinel. The absence of a peak at appr. 250–300 °C implies the absence of the free gibbsite Al(OH)3 or goethite FeOOH. By size of reflexes in the range of 2θ20–22°it was estimated the Hinckley index (HI) as the structure order indicator: HI made 1.76 that indicated rather high degree of order. After a heat treatment at 400 °С index reduced to 1.69. Crystallite size along the c-axis amounted 61.5 nm. Mullite was the main phase at 1200 °С.