Synopsis:The change of coke properties in the blast furnace was investigated using samples from Higashida No. 5,
HirohataNo. 1 and Kukioka No. 4 blast furnaces, which were dissected after being quenched with water in normal operating state. The results of the research are summarized as follows:1) The change of coke properties becomes remarkable below the lower shaft level. 2) According to the microscopic observation, this change of coke properties seems to be due to the selective carbon solution-loss reaction at specified textures of coke, resulting in the weakening of strength and the generation of fine particles. 3) This phenomenon is particularly remarkable around the race-way of blast furnace.
An automatic sy stem Jor evaluating the coking coals was develojled at Nippon Steel Corporation in 1974. In this system, the reflectance oj coal is measured automatically and rapidly and then converted to the coking parameters based on the coal petrographical point qf view. It takes only 30-100 min to make 2 X 10 4-1 X 10 5 measurements oj reflectance in a sample. From the measured reflectance distribution Jar the whole maceral and vitrillite alone, the coking index are comjmted. Many applications qf the automatic system Jar coal jletrograpJ~), have been developed with satisfactory results.
Synopsis:The large perfect crystals of typical calcium ferrites were successfully synthesized by "solid-liquid reaction method" from mixtures correspond to CaO Fe203, 2CaO.Fe203, Ca0.2Fe203, 4CaO.Fe0. 4Fe2O3, 3CaO.Fe0.7Fe203 and 4CaO.Fe0•8Fe203, respectively. The mineralogical properties of synthesized calcium ferrites, i. e., optical characteristics, reflectivity, etching effect, microhardness and Xray diffraction pattern, were examined.Besides Ca0.2Fe203 compound, a ternary calcium ferrite compound proved to exist, whose chemical composition is approximately similar to Ca0.2Fe203 and is estimated to be one of the followings 3CaO.Fe0.7Fe203, 4CaO.Fe0.9Fe203, or 4Ca0.2Fe0.9Fe203. X-ray diffraction patterns of CaO. Fe203, 2CaO.Fe203 and 4CaO.Fe0.4Fe203 were in agreement with the data of previous workers. For determining metallurgical properties of binary calcium ferrites, about 2 kg samples are synthesized by solid state reaction. The conventional testing methods for iron ores were applied, i. e., the JIS methods for testing reducibility, the rotation strength after reducibility test, the degradation strength after reduction at lower temperatures, and the temperature of shrinkage, softening and melting. The degradation strength after low temperature reduction of binary calcium ferrites is much higher than that of actual self-fluxed sinter.
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