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질소 용해반응기구에 미치는 슬래그 염기도의 영향에 관한 연구
민동준 대한금속재료학회(대한금속학회) 1995 대한금속·재료학회지 Vol.33 No.9
The nitrogen solubility and nitride capacity of the BaO-B₂O₃ and CaO-B₂O₃ slag systems at high temperatures were measured in order to understand the nitrogen solution mechanism of slag by using a chemical equilibration technique. The present slag systems were chosen because they have wide liquid regions at the temperature of interest and were expected to show two different types of nitride dissolution behaviors. The nitride capacities of both systems showed some minimum values with changing composition. This was explained by considering that nitrogen can dissolve into slag as "free nitride" at high basicities and "nitride incorporated" with the network for acidic slags. The change of nitride capacity with optical basicity and the activity of the basic component followed the predicted behavior for the proposed solution mechanism. The nitride capacity of the BaO-B₂O₃ system is considerably greater than that of the CaO-B₂O₃ system because BaO is a more basic oxide than CaO.
민동준 대한금속재료학회(대한금속학회) 1995 대한금속·재료학회지 Vol.33 No.9
Present study was carried out to understand the thermodynamic behavior of BaO-B₂O₃ slag system at high temperature by chemical equilibration technique. Also, thermodynamic properties of Ag-Ba binary system at high temperature was measured to carry out the above mentioned investigation by the same technique. Thermodynamic behavior of Ba in Ag melts shows negaive deviation from ideal solution and can be expressed quantitatively by using α function concept as follows : logγ_(Ra)=2.63(1-X_(Ba))² α=logγ_(Ba)/(1-X_(Ba))²=2.3-7700/T BaO activity was increased with increasing the mole fraction of BaO and shows the negative deviation from the ideal sloution model. Thermodynamic properties of BaO shows similar behavior with CaO system. The thermodynamic properties of BaO in BaO-B₂O₃ slag system could be related with the stability of BaO-B₂O₃ melts which was considered to be stable compound at high temperature as a 3BaO·B₂O₃ composition. also, comparison between BaO and CaO activity and optical basicity was carried out to confirm relative strength of BaO basicity to CaO. BaO system shows higher optical basicity than CaO system at the same activity of those basic oxide, This fact may imply that BaO was more effective oxide for the refining reagents because of strong basicity.
고온에서의 Fe-C-S 합금 중 Cu 의 열역학적 거동에 관한 연구
민동준,허기행,김대환,이창희 대한금속재료학회(대한금속학회) 1998 대한금속·재료학회지 Vol.36 No.12
The thermodynamic behavior of copper in molten Fe-C-S alloy at high temperature was investigated by chemical equilibrating technique. The effects of copper, carbon, sulfur content and temperature on the activity coefficient of copper in molten pure iron and carbon saturated were was determined by measuring the distribution ratio between silver and Fe-C-S-Cu alloy. The activity coefficient of copper in molteniren and carbon saturated iron at infinite dilution of copper were measured 11.02 and 28.50 at 1823K respectively. The interaction parameter between copper and copper, sulfur and carbon in molten iron at 1823K, was estimated as follows; ε^(Cu)_(Cu) = -4.80, ε^S_(Cu) = -2.544, ε^C_(Cu) = -4.60 The dependence of the activity coefficient in molten Fe-C alloy on temperature was determined as follows; For molten pure iron : lnγ^(oFe)_(Cu) = 4370/T For Fe-2wt%C : lnγ^(oFe-2wt%C)_(Cu) = 0.72 + 3840/T For carbon saturated iron : lnγ^(oFe_C)_(Cu) = 1.11 + 4100/T Combining the effect of temperature and the alloying component, the activity coefficient of copper could be expressed as follows ; lnγ^(Fe-C-S)_(Cu) = 4370/T·(1-X_(Cu))² + (2.15 + 4600/T)·2.54·X_s The possibility of removal of copper from steel by slag refing and evaporating technique was discussed.
나노영가철/활성탄 입자전극과 과황산을 이용한 3차원 전기화학적 산화공정
민동준,김철용,안준영,조수빈,황인성 한국지하수토양환경학회 2018 지하수토양환경 Vol.23 No.6
A three-dimensional electrochemical process using nanosized zero-valent iron (NZVI)/activated carbon (AC) particleelectrode and persulfate (PS) was developed for oxidizing pollutants. X-ray diffraction (XRD), scanning electronmicroscopy with energy dispersive spectroscopy (SEM-EDS), and Brunauer-Emmett-Teller (BET) surface area analysiswere performed to characterize particle electrode. XRD and SEM-EDS analysis confirmed that NZVI was impregnated onthe surface of AC. Compared with the conventional two-dimensional electrochemical process, the three-dimensionalparticle electrode process achieved three times higher efficiency in phenol removal. The system with current density of 5mA/cm2 exhibited the highest phenol removal efficiency among the systems employing 1, 5, and 10 mA/cm2. The removalefficiency of phenol increased as the Fe contents in the particle electrode increased. The particle electrode achieved morethan 70% of phenol removal until it was reused for three times. The sulfate radical played a predominant role in phenolremoval according to the radical scavenging test.
Recent Advances in Understanding Physical Properties of Metallurgical Slags
민동준,Fumitaka Tsukihashi 대한금속·재료학회 2017 METALS AND MATERIALS International Vol.23 No.1
Present-day knowledge of the structure and physical properties of metallurgical slags is summarized to address structure-property and inter-property relationships. Physical properties of slags including viscosity, electrical conductivity, and surface tension is reviewed focusing on the effect of slag structure, which is comprehensively evaluated using FT-IT, Raman, and MAS-NMR spectroscopy. The effect of the slag composition on slag structure and property is reviewed in detail: Compositional effect encompasses traditional concepts of basicity, network-forming behaviors of anions, and secondary impact of network-modifying cations. Secondary objective of this review is elucidating the mutual relationship between physical properties of slags. For instance, the relationship between slag viscosity and electrical conductivity is suggested by Walden’s rule and discussed based on the experimental results. Slag foaming index is also introduced as a comprehensive understanding method of physical properties of slags. The dimensional analysis was made to address the effect of viscosity, density, and surface tension on the foaming index of slags.
전로 슬래그의 용융환원 공정에 관한 물질 및 에너지수지
민동준,정원변,백종문 대한금속재료학회(대한금속학회) 1997 대한금속·재료학회지 Vol.35 No.2
The computer simulation model was established to verify the applicability of smelting reduction concepts to converter slag which becomes an issue on the environmental and recycling aspects. The computer simulation model provides the following results. The utilization of latent energy of converter slag after tap is a very effective and reasonable method for saving energy. Also, the increase of post combustion ratio and heat transfer efficiency are effective ways in saving energy. But in order to increase PCR, recovery efficiency of post combustion energy has to be higher than 85% HTC to satisfy both refractory life and energy efficiency. Coke is a most useful fuel source because it shows low dependence to post combustion ratio and low hydrogen content. In the present process, the quality of hot metal would be expected to be at a similar level with that of the blast furnace. The utilization of scrap was also possible to maximize the advantages of the present process which were high temperature and chemical dilution with hot metal. In the case of scrap, energy consumption increases slightly due to preheating of scrap. Consequently, the concept of the present process provides one possibility of integrating recyclable waste materials such as converter slag, coke oven dust, life terminated acidic refractory, scrap by smelting reduction process.