酸化크롬의 還元機構 (Ⅰ)

黃龍吉,康熙南 동아대학교 공과대학 부설 한국자원개발연구소 1984 硏究報告 Vol.8 No.1

The reduction of chromium oxide by carbon in the range of 1150°~ 1300℃ under the Ar atmosphere has been investigated. The results obtained from the experiment is summarized as follow; 1) From the results of thermal analysis by T.G-D.T.A., metallic chromium and chromium carbide were formed in the range of endothermic reaction. And in this range, the rate of weight loss was reached 29.9% 2) As the reaction temperature increased, the reaction products become coarser, and in the view of area frequency distribution, the particle size from 31㎛ to 40㎛ became coarser about 4 times at the 1300℃ than the 1150℃ 3) From the X-ray diffraction analysis, reaction products at the 1200℃ were mainly Cr₃C₂ and Cr_(7)C₃, and at the 1300℃ the rection products were Cr and Cr_(7)C₃. 4) The reduction rate calculated with the reaction rate of metallic chromium was 98.7%

Fe-Cu-As 3원계의 비소 활량에 관해서

黃龍吉,姜憲贊 동아대학교 공과대학 부설 한국자원개발연구소 1985 硏究報告 Vol.9 No.2

Fundamental studies of the behaviour of arsenic in copper smelting as well as the phase relations and arsenic activity in liquid Fe-Cu-As systems were undertaken. The arsenic activity in the liquid Fe-As stystems, Cu-As systems and Fe-Cu-As systems was determined at 1150℃ by the use of an isopiestic method. 1. The value of arsenic activity coefficient, γ°_(As)(1), was calculated to be 2×10^(-3) from the experimetal data by the solute arsenic at infinite dilution in Fe-As system at 1150℃. 2. In the genral case of arsenic has a greater affinity for Fe-As systems than for Cu-As systems. 3. The arsenic activity of Fe-Cu-As systems increases drastically in the high concentration range. 4. The liquidus and Solidus lines divide the equilbrium diagram into Fe-Cu-As system at 1150℃.

水熱處理 및 하소에 의한 燐酸니켈 顔科特性의 改善

黃龍吉,薛秀德 동아대학교 공과대학 부설 한국자원개발연구소 1979 硏究報告 Vol.4 No.1

黃色 燐酸니켈((α-Ni₂P₂O_(7))의 特性改善을 目的으로 이것의 水熱處理 效果를 檢討하였다. 燐酸니켈을 加數分解法에 의해 黃酸니켈 및 炭酸니켈에 燐酸암모늄을 添加시켜 混合시킨 뒤 稀燐酸水溶液 중에 分散시켜 100℃, 5시간 水熱處理해서 얻어진 試料를 900℃,3시간가량 하燒시킨 결과 90% 이상의 α-Ni₂P₂O_(7)을 含有한 鮮明한 黃色의 加熱生成物이 얻어졌다. Yellow nickel phosphate (α-Ni₂P₂O_(7)) was synthesized by the seed method and the autoclaved it in H₃PO₄ solution at 100℃ for 5 hours. When hydrolyzed sample was calcined with temperature range 600℃ for 3 hours, 90% and over calcined material was recovered in the form of α-Ni₂P₂O_(7) with a yellow colour.

鋼內 介在物의 Br-化合物 形成에 關하여

黃龍吉,李相允,金營三,成章鉉 東亞大學校 大學院 1980 大學院論文集 Vol.4 No.2

The results obtained from the experiment to make a comparison between thermal characteristics and chemical reactions of 10% Br-Methanol treated oxides, and inclusions and oxides in 18Cr-8Ni stainless steel can be concluded as follows; 1. It has been shown that when MnO2, Cr2O3, Fe2O3 and SiO2 are heated, they all give exothermic characteristics in the temperature range about 200 to 300℃, but they tend to be heated up endothermically in the range 300 to 900℃, except for the fact that when the reaction 3MnO2=Mn3O4+O2 occurs at 600℃, peak showing endothermic reaction is observed. 2. Specimens made by mixing some of oxides such as MnO2, SiO2, Fe2O3 and Cr2O3 and uheir complex compunds and inclusins have all produced similar reactions which are characterized by showing an exothermic for temperatures of up to approximately 300℃ and an endothermic for the temperature range 300 to 900℃. However, it is noted that some oxides containing Mn give a sharp peak which represents endothermic reaction. 3. Below 100℃ the thermal analysis curves obtained from specimens made by reacting each complex compound with 10% Br-Methanol have been shown to be similar to these for specimens not rected with 10% Br-Methanol, showing endothermic heating for temperatures from about 150 to 200℃ endothermic heating for higher temperatures than 200℃. 4. The X-ray diffraction analysis has shown that oxides such as Mn3O4 and Cr2O3 are observed from the complex compound with a ratio MnO2: Cr2O3=1:1, whereas in the case of the compound with a ratio MnO2:Cr2O3=2:1 peak for Mn3O4 only is observable without any trace for Cr2O3 on the diffraction chart. Furthermore in the compound of Fe2O3 and Cr2O3 the peak for Cr2O3 has been determined, but no peak for Fe2O3 can be found. 5. The x-ray diffraction analysis has also presented that in inclusions in steel and complex oxides extracted by using 10% Br-Methanol the inclusions give peaks for Cr2O3 only, and peaks for Mn3O4 and Cr2O3 are obtainable. Based on this observation only when inclusions in steel are extacted by using 10% Br-Methanol amorphous structure is formed by Br, but crystalline oxides are thought to be unchanged to the amorphous.

FeSO₄의 熱分析및 Fe₃SO₄ 生成에 관한 硏究

黃龍吉,薛秀德,成周慶 東亞大學校 1975 東亞論叢 Vol.12 No.2

500℃로 하소시킨 황산제일철을 原料로 해서 鐵黑顔料를 製造하는 實驗이다. 500℃로 하소시킨 황산제일철 용액을 수소이온농도 7∼8, 反應溫度 100℃, 空氣加壓力 3氣壓, 反應時間 2時間으로 加水分解시켜본 結果 鐵黑이 90%以上 生成되었다. The formation of black iron oxide in a calcined Iron(Ⅱ) sulfate at a temperature of 500℃ was studied in the solution at a temperature of 100℃ under 3 atmospheres. When calcined Iron (Ⅱ) sulfate was hydrolyzed under 3 atmospheres in the solution with pH range 7 to 8 for 2 hour at temperature of 100℃, 90% of iron was recovered in a form of black iron oxide.

17Cr Stainless鋼의 介在物分布에 관한 硏究

黃龍吉,成章鉉,閔庚和 東亞大學校 大學院 1978 大學院論文集 Vol.2 No.-

To study the distribution, contents and structure of inclusion in 17Cr stainless steel, the samples were obtained with elapes time and Fe-Si addition after melted down in the high frequence induction furnace. And the distribution of inclusions, inclusion contents and the structure of inclusions were studied by means of optical microscopy, Br-Methanol method and X-ray technique. From the above experiments, the following conclusions could be summerized. 1) The inclusions of holding samples after melted down were spheroidal shape. And with the increase of holding time, the inclusion contents increased from 0.073% to 0.125%. And the distribution of fine inclusions decreased and the coarse inclusions increased from 2.0-3.ou:76% to 2.0-3.0:40%. 2) The inclusions of Fe-Si treated sample were dispersed and granular type. And the inclusion contents were increased compared with the holding samples after melted down. And the inclusions were distributed to fine one. 3) The inclusions were composed of Fe3O4, Cr2O3 and amorphous compound of Ni,Mo, Mn etc.

製鍊 Slag의 顯熱利用에 관한 基礎硏究

李相和,黃龍吉 東亞大學校 大學院 1984 大學院論文集 Vol.8 No.2

On the purpose of developing the fundamental data, calcium hydroxide for the temperature accumulating media was investigared. The results obtained from the experiment are summarized as follows: 1. 1.37 Kg of calcium hydroxide can be calcinated using the 1 Kg of smeting slag maintained. 2. At calcination, maximum temperature of reacted materials and reactor spaces temperature is at 142℃ and 90℃ respectively. 3. 3 moles of H₂O per 1 mole CaO has been for the long maintanence in the case of maintaining a maximum temperature range and elevating to the 90℃ for the 90 minutes can be obtained by using the adiabatic reaction chamber.

18Cr-8Ni 및 17Cr Stainless鋼의 硅素에 의한 脫酸擧動에 관한 硏究

李鍾文,黃龍吉 釜産工業大學校 1984 論文集 Vol.25 No.-

The phenomena of decreasing chromium contents, the effect of deoxidation by adding silicon and the floating mechanism of slags, the crystal structure of inclusions for 18Cr-8Ni and 17Cr stainless steel respectively have been investigated. The scraps are melted by a high frequency induction furnace. The results are as follows; 1) The chromium contents in 17Cr stainless steel exhibits a remarkable decrease more than 1 hour is required for melting the scraps. The chromium contents in 18Cr-iNi stainless steel exhibits a small decrease, as 1.67% until holding for 2 hours. The required melting time is 1 hour. 2) The floating rate of spheroidal inclusions is greater than the floating rate of dispersed inclusions form molten bath. 3) The slags of 17Cr stainless steel before deoxidation and after deoxidation by adding silicon are FeO·Cr??O₃ and SiO₂, the slags of 18Cr-8Ni stainless steel is FeO·Cr??O₃, which can be seen by X-ray diffraction method. 4) The inclusions in 18Cr-8Ni and 17Cr stainless steel (containing less than 0.8% Si and less than 1.0% Mn, as cast) are Cr??O₃and Fe??O₄as can be seen by X-ray diffraction method.

용융동및 Speiss와 Calcium Ferrite Slag사이에서 As의 분배평형에 관해서

강헌찬,황용길 동아대학교 공과대학 부설 한국자원개발연구소 1987 硏究報告 Vol.11 No.2

The distribution of arsenic between calcium ferrite slag and liquid copper was measured at 1473 K under controlled CO-CO₂ atmospheres. The distribution ratios defined by % X in slag/%X in metal, were plotted against the oxygen potential. The distribution ratios of arsenic between speiss and calcium ferrite slag were also investigated. From the above experiments, the results obtained are as follows : 1. The liquidus and solidus lines divide the equilibrium diagram into Fe-Cu-As system at 1150℃. 2. In general arsenic has a greater affinity fir Fe-As systems than for Cu-As systems. 3. The distribution ratios of arsenic between speiss or liquid copper and slag increase with the increased content of the CaO in calcium ferrite slag or oxygen potential.

製鋼粉塵의 處理

姜憲贊,黃龍吉 東亞大學校 1980 東亞論叢 Vol.17 No.2

裝鋼粉?을 還元해서 얻은 粗酸化亞鉛을 소-다灰로 90℃에서 中和處理한 結果 다음과 같은 結論을 얻었다. 粗酸化亞鉛(Crude zinc oxide, 54%Zn, 9.3%Pb, 13%Cl₂)은 鹽基性 黃酸鉛(Lead basic sulphate0形의 Pb₄O₃SO₄·2H₂O와 Pb₃O₂SO₄만 結晶質이고, 亞鉛과 鹽素의 化合物의 結晶은 確認할 수 없었다. 中和反應 時 Soda-ash使用量은 化學量論的 理論量만 必要했다. 中和反應에 의해 生成된 沈澱物은 鹽基性 炭山亞鉛(Zinc basic carbonate:4ZnO·CO₂·4H₂O)과 鹽基性 炭山鉛(Lead basic carbonate:Pb₃(CO₃)₂(OH)₂)의 形態로 되어 있었다. 또 脫鹽處理한 化合物을 180 gr/ℓ의 H₂SO₄로 浸出한 結果, 浸出液은 130 gr/ℓ Cl₂이고 浸出殘渣는 主로 黃酸鉛(PbSO₄)으로 되어 있었다. After neutralization-treating the crude zinc oxide obtained from the reduction of steel making dusts at a temperature of 90℃, the following results were obtained. 1) The crude zinc oxide (54% Zn, 9.3% Pb, 13% Cl) was found to be crystalline consisting of Pb₄O₃SO₄·2H₂O and Pb₃O₂SO₄with type of lead basic sulphate, however, a crystal of zinc and chlorine compound was not able to be confirmed. 2) The theoretical amount determined in a stoichimetric calculation ash was only required for the reaction of neutralization. 3) The precipitate formed by neutralization reaction was comprixed of zinc basic carbonate (4ZnO·CO₂·4H₂O) and lead basic carbonate (Pb₃(CO₃)₂(OH)₂). 4) It was found by leaching dechlorinated compounds with 180g/ℓof H₂SO₄that the leached solution contained 130g/ℓof Zn and 200 mg/ℓof Cl₂and that the leaching residue consisted mainly of lead sulphate(PbSO₄)