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By Tateo Usui

In the course of carbonization of coal under a rising temperature condition, volatile matter (V.M.) is released. The kind and amount of V.M. released depend on the kind of coal. Components of V.M. are tar, hydrocarbons (CH4, C2H4, C2H6, C3H8), CO, CO2 and H2, which are released in this order as a function of carbonization temperature. When the carbonization of coal under a rising temperature condition is interrupted at a certain temperature, TC, max, semi-coal-char with residual V.M. is obtained. If some optimum interruption-temperature is chosen, small but most suitable amount of V.M., namely H2, is retained. When the semi-coal-char thus obtained is heated again under the same rising temperature conditions but up to more than TC, max (1), the residual V.M. is released from just around TC, max (1). We propose novel iron ore agglomerate bearing such semi-coal-char with some strength. While simple iron ore agglomerate bearing coal char will start the reduction reaction as solid-solid reaction at somewhat higher temperature, the proposed one will start the reduction reaction as gas-solid reaction at somewhat lower temperature but a little higher than TC, max. Samples of semi-coal-char and novel iron ore agglomerate bearing such semi-coal-char have been prepared and evaluated.

Jan 1, 2006

By Chuan-fu Zhang

In present work, the physical properties of molten FenO-MgO-CaO-SiO2 slags were measured .It is shown by the results that when the slag composition is as follow: MgO 8%~12%, CaO 2%~8%, Fe/SiO2 1.2~1.6, the viscosity of the slags decreases with the increase of temperature. When the Fe/SiO2ratio and the MgO content are fixed, the electrical conductivity increases and the viscosity decreases as CaO content increasing, while the content of CaO exceeds 6% its influence weakens. When the MgO content is 11% and the CaO is 6%, the viscosity of the slag decreases markedly as the increase of Fe/SiO2 ratio. Its influence to viscosity is inconspicuous when the Fe/SiO2 ratio exceeds 1.5. When the CaO content is 6% and Fe/SiO2 is 1.2, the electrical conductivity decreases with the increase of MgO content as temperature is below 1290, but increases when temperature is above 1290. When the MgO content is 11% and the Fe/SiO2 ratio is 1.2, the electrical conductivity increases with the increase of CaO content. When the CaO content is 6% and MgO content is 11%, the electrical conductivity increases as the increase of Fe/SiO2 ratio, while its influence weakens as the temperature increases continuously. The electrical conductivity rises when temperature increases at any slag content. The melting temperatures of FenO-MgO-CaO-SiO2 semi- synthesis slags from this work were below 1290.

Jan 1, 2006

By Pekka Parvinen, Saija Luukkanen, Pentti Pirkonen, Väinö Hintikka, Hannu Sekki

In the study was developed a new method for the treatment soils contaminated by polychlorinated dibenzodioxin and dibenzofuran. The method is based on attrition of soil so that the contaminants absorbed on the particle surfaces are liberated with the fine fraction formed in the attrition process. Same the attrition process produces active surface which can absorb the free contaminants. Before starting the remediation process must be decided the limit value under which the residual concentration must lie. Then in the laboratory is performed an experiment in the base of which is determined the grain size level; material under which much be removed together with the contaminant. In the real sample has been found that after the attrition the limit value 0.5 ng/g (I-TEQ) is obtained when the fine under 0.1mm fraction (20% of the original soils amount) is removed together with the contaminants 96% (original level 10 ng/g; 100%).

Jan 1, 2008

By Du Sichen

The present paper presents the modeling of gas-solid reactions in the case of the decomposition of CaCO3, describing the reaction kinetics on the basis of heat-transfer concepts which could be compared with thermogravimetric results. In the case of solid-solid reactions, the present paper describes the model developed for describing solid-solid reactions from dynamic X-ray diffraction technique, developed by the present team. The model has been successful in explaining the formation of spinel from MgO and Al2O3.

Jan 1, 2006