Advanced Materials Research Vols. 634-638

Abstract: Removal of boron is one of the greatest barriers in the process of upgrading metallurgical grade silicon (MG-Si) to solar grade silicon (SoG-Si). In this work, a chloride molten salt was used as a new refining reagent for removal of boron from MG-Si. The theoretical supporting for chloride molten salt refining was studied by the thermodynamic analysis at first, which testified that boron could be volatilized and removed from MG-Si melt by generating the gaseous boron chloride species. Then the experiments for the removal of boron were carried out using the chloride molten salt with the different conditions of refining time and the ratio of chloride molten salt to MG-Si. The results showed that the boron content in refined silicon was successfully reduced from 22.0×10-6 to 3.0×10-6 in a medium frequency induction furnace at 1695 K for 2h.

Abstract: According to the continuum assumption and the mass transfer controlled regime, a mathematical model describing the combined diffusion, convection and the reversible chemical reactions in a porous packed bed was established and numerically solved. The simulation results are validated by comparing with the experimental data. The calculated results showed that, an increase in convection velocity causes an increase in Thielet number and an opposite effect for Th/Pe ratio. Therefore, the ability of chemical reaction increases under the condition of increasing convection velocity. But the utilization of reaction gas decreases. The influence of main parameters on the reaction conversion all can be analyzed by calculating the Thiele number and the Peclet number.

Abstract: The thermodynamics and dynamics characteristics of solid fuel combustion in sintering mixture were investigated in this paper. The combustion behavior of solid fuel in mixture was analyzed by thermogravimetric experiment, the solid fuel conversion with different fuel size and oxygen concentration was got by the experiment, the dynamic parameters: activation energy E and the pre-exponential A were theoretically calculated based on reaction kinetics model. The size and oxygen concentration were also the influence factors of combustion rate. The empirical data can be used to guide the simulation of actual sintering process and the dynamic parameters can be used in the establishment of the sintering model.

Abstract: The SiO2 related phases in the vanadium slag exist in form of orthosilicate matter, the first solidified vanadium-containing phases would be surrounded or wrapped by the last solidified orthosilicate. So the wrapped orthosilicate have to be broken to achieve the extraction of vanadium from vanadium slag, therefore, to study the characteristics of SiO2 related phases in the vanadium slag will offer a practical guidance to understand the phase change of vanadium slag, The free SiO2 phase isn’t generated in the process of vanadium slag production in this paper by means of combination of vanadium slag compositions, petrographic analysis, Scanning electron microscopy -energy spectrum analysis (SEM-EDS) with the phase diagram of MgO-SiO2-FeO-CaO pseudo-ternary system calculated by Factsage, and SiO2 is mostly present in the olivine and pyroxene minerals.

Abstract: The active ingredient of catalysts is generally dispersed on porous supports of inert metal oxides to augment its catalytic activity. In this paper, the dispersion and topography of CeO2 supported on γ-Al2O3 was studied by means of XRD. The monolayer coverage of CeO2 was determined by internal-standard method with NiO reference material. Highly dispersed CeO2 would appear and encapsulate outside theγ-Al2O3 support surface evenly when CeO2 loading was below its monolayer coverage; above the monolayer coverage, crystalline CeO2 would appear.

Abstract: We studied the nitrogen macrosegregation of the HNS, and found that there were severe vertical segregation and horizontal segregation. Both of them are normal segregation. The study shown that the overflow area of nitrogen bubbles in the process of solidification is due to the nitrogen macrosegregation.

Abstract: According to the actual situation of refining high nitrogen steel with the laboratory high pressure reaction axe, the molten steel flow field in the high-pressure and bottom-blowing nitrogen reactor was simulated by using the software Fluent. The rules of the influence of pressure factor on the molten steel flow field characteristics, turbulent kinetic energy and gas content were explored. According to the characteristics of the flow field and gas-liquid two phase structure, the rules of the influence of pressure factor on nitrogen concentration distribution were analyzed. So some useful theoretical basis and guidance were provided for laboratory refining high nitrogen steel and industrial production in the future.

Abstract: According to the coexistence theory of melted slag structure, a calculation model of mass action concentrations for CaO-B2O3-SiO2 slag system has been established, by which the mass action concentrations of all structure units in CaO-B2O3-SiO2 systems are calculated. The results indicate that the activities of CaO and 2CaO•SiO2 can be decreased effectively by B2O3. Furthermore, when the slag basicity is higher than 2.0, the activity of 2CaO•SiO2 increases firstly and then decreases with the increasing of B2O3 content. The activity of CaO increases with the increasing of slag basicity. When the basicity is less than 2.2, the activity of 2CaO•SiO2 increases with the increase of slag basicity. Moreover, when the basicity is 2.2, the activity of 2CaO•SiO2 reaches the maximum value. In another word, the activity of 2CaO•SiO2 decreases with the increase of slag basicity on the condition that the slag basicity exceeds 2.2. B2O3 exists in the slag in the form of CaO•B2O3, 2CaO•B2O3 and 3CaO•B2O3.

Abstract: Introduce characters and applications of granulation techniques of the molten blast furnace slag in contemporary China, describe characters and design ideas of two types of granulation boxes, represent three types of circulating granulation water systems, put forward matching proposal between the molten slag granulation system and the circulating granulation water system, analyze contemporary research and problems of waste heat recovery of the molten BF slag.

Abstract: Ability to improve cooling system, avoid untimely damage of BF lining and coolers, reduce maintenance frequency and prolong maintenance period during the furnace campaign, it is imperative for BF longevity. Describe development of cooling system, illustrate economic rationality and safe reliability of closed loop soft water cooling system, stress equipments, process, design, system measurement and control on closed loop soft water cooling system for Shougang Qiangang No.3 BF. Take full account of BF working condition, lining structure and corrosion mechanism, combine actual investment, choose advanced and rational coolers; develop segmentation design for cooling system, strengthen BF cooling effectively, boost system steering rate in order to reduce temperature of brick lining, prolong lifetime of brick lining, keep the lining integrity, maintain rational furnace profile, ensure BF production and longevity.