• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.2
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• pp.162-165
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• 2002

To determine changes of heme compounds on lipid oxidation during repeat heating in white muscled fish (yellowfin sole and yellow croaker), myoglobin, metmyoglobin, total iron, nonheme iron and heme iron contents were analysed. Myoglobin content was decreased in the step of repeat heating. Especially, it was decreased the most rapidly roasted at 180$^{\circ}C$ for 20 min in fillet samples. The skinless fillet roasted at the lower temperature resulted in the higher level of metmyoglobin associated with the reduced myoglobin. Regardless of roasted temperature and time, total iron content was not change in contrast of raw meat throughout processing. Nonheme iron content was increased, but heme iron content was decreased during roasted, heated and reheated.

• Resources Recycling
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• v.31 no.2
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• pp.49-55
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• 2022

In the present study, the thermodynamic evaluation of the sulfate-roasting process was conducted to extract vanadium from the Korean vanadium titano-magnetite ore. The leaching efficiency of vanadium and other impurities was analyzed for varying roasting temperatures and addition of Na₂SO₄. In the case of sulfate roasting, the roasting temperature was 200 ℃ higher than that previously observed Na₂CO₃ roasting. However, the higher leaching efficiency of vanadium and lower leaching efficiency of other impurities, such as aluminum and silicon, were observed. The high selectivity for the extraction of vanadium in sulfate roasting would result from the reaction mechanism between SO₂ gas and vanadium concentrate.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.708-713
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• 1997

Various chemical indices were analyzed to clarify the tendency of rancidity during the repeats of heating so called roasting heating and/or reheating in dark muscled fish (mackerel and pacific saury). The total lipid contents of fresh mackerel and pacific saury were $36.7\%\;and\;28.4\%$ in saturated fatty acid, $33.0\%\;and\;20.2\%$ in monoenoic acid, and $29.9\%\;and\;49.7\%$ in polyenoic acid, respectively. The ratios of unsaturated fatty acid (UFA)/Saturated fatty acid (SFA) were 1.7, 2.5 and content of total lipid was $16.5\%\;and\;13.7\%$, respectively. Peroxide content gradually increased after roasting heating and reheating in mackerel while it decreased after reheating in pacific saury. Thiobarbituric acid value also increased during roasting and heating in all the samples but decreased after reheating. Acid value increased after roasting heating and reheating in all samples, particularly it was high in pacific saury which have a high composition of UFA. More conjugated dienes were formed when the meat was roasted at $180^{\circ}C$ than at $200^{\circ}C\;or\;220^{\circ}C$, and in the filet with skin than the skinless.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.94-94
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• 2014

본 연구는 탈질용 폐 SCR 촉매로부터 유가금속인 바나듐과 텅스텐을 회수하기 위하여 고온 소다배소, 수침출, 침전 및 용매추출 실험 순으로 진행하였다. 소다배소는 $Na_2CO_3$ 첨가량 5당량, 폐촉매 평균 입자크기 $54{\mu}m$, 배소온도 $850^{\circ}C$, 배소시간 120분의 조건이 적절하였고, 소다배소 산물의 수침출 실험은 배소산물 입자크기 $-45{\mu}m$, 침출온도 $40^{\circ}C$, 침출시간 30분 및 광액밀도 10%의 조건이 적절하였다. 이와 같은 조건하에서 소다배소 및 수침출 실험을 수행한 결과, 바나듐 성분 약 46%와 텅스텐 성분 약 92%가 침출 되었다. 수침출 공정에서 얻어진 바나듐과 텅스텐이 함께 침출된 침출용액으로부터 바나듐 성분을 선택적으로 침전시키기 위하여 MgCl2를 사용하여 침전실험을 수행하였으나, 바나듐 성분이 침전될 때 텅스텐 성분이 함께 침전되어 큰 손실율을 나타내었다. 또한, 침출용액 내의 바나듐과 텅스텐 성분을 분리하기 위하여 용매추출 실험을 수행하였다. 아민계열의 추출제인 Alamine 336 및 Aliquat 336을 사용한 용매추출 실험에서 바나듐과 텅스텐 성분 모두 90% 이상 추출되었다. 이후 수행된 탈거실험에서 대부분의 역추출제에 의해 바나듐과 텅스텐은 동시에 탈거되었다. 그러나 Alamine 336을 추출제로 사용한 유기상의 탈거실험에서 NaCl 및 NH4Cl 용액을 탈거용액으로 사용하였을 경우에 바나듐과 텅스텐이 선택적으로 탈거될 수 있는 가능성을 나타내었다. 반면에 Aliquat 336을 추출제로 사용한 유기상의 탈거실험의 경우, NaOH 용액이 가장 선택적인 탈거용액임을 확인하였다.

• Resources Recycling
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• v.21 no.6
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• pp.65-73
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• 2012

Selective catalytic reduction(SCR) catalysts are obtained from de-NOx system of thermoelectric power plant. A process was developed for valuable metals such as vanadium and tungsten recovery from spent SCR catalyst by using soda roasting followed by water leaching. Spent SCR catalyst having $V_2O_5$(1.23 mass %) and $WO_3$(7.73 mass %). For getting soluble metal forms of the targeted metals like vanadium and tungsten soda roasting process was implemented. In soda roasting process, sodium carbonate added 5 equivalent ratio at roasted temperature $850^{\circ}C$ with 120 min roasted time for $544{\mu}m$ particle size of spent SCR catalyst. After soda roasting process moved to water leaching for roasted spent catalyst. Before leaching process the roasted spent catalyst was grinded up to $-45{\mu}m$ size. The leaching time is 30 min at $40^{\circ}C$ temperature, 10 % pulp density. The final leaching efficiency obtained 46 % of vanadium and 92 % of tungsten from present process.

• Korean Journal of Food Science and Technology
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• v.27 no.6
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• pp.902-908
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• 1995

Oxidative factors of lipid in the roasted laver Porphyra tenera(RL) and roasted-seasoned laver(R-SL) depending on various light sources, water activities, packaging materials and storage temperatures were investigated by peroxide value and color. Major fatty acids of RL were 46.4% eicosapentaenoic acid and 14.9% palmitic acid. Lipid oxidation was decreased in order of darkness, incandescent and fluorescent, decreased sharply with the decrease of water activity and temperature, and also reduced by the packaging material with strong barriers of water vapor, oxygen and light. From kinetics of lipid oxidation, it was supposed that oxidation of R-SL was three times faster than RL. On the other hand, reduction of the total chlorophyll content in RL was stronger than R-SL.

• Resources Recycling
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• v.7 no.4
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• pp.64-75
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• 1998

The purpose of this study is to produce high putity composite powder composed of Fe-oxide, Mn-oxide and Mn-ferrite having superior homogencity in composition and particle size distribution by co-roasting process. Binary component metal (Fe, Mn) chloride solutions were produced by dissolving mill scale and ferro-mangancse alloy in hydrochloric acid. These chloride solutions contained the impurities such as SiO$_{2}$, P, Al, Ca and Na, which were originated from the Fe/Mn source materials. The neutralization and polymeric coagulant method were adoped to refine the hydrochloric liquor. When pH is far below the isoelectric point (pH 2-3), the SiO$_{2}$ was the most effectively reduced element, while other impurities remained unchanged. By increasing pH above 3, most of the impurities could be reduced effectively due to the coprecipitation reaction. The polymeric coagulants such as poly vinyl alcohol, resin amine and ammonium molybdate were found to have no effect on the spray roaster designed by the authors. The produced oxide powders were confirmed to be mixtures of Fe-oxide, Mn-oxide and mn-ferrite. the powders were homogeneously mixed and the particle size increased sleeply with increasing co-roasting temperature.

• Resources Recycling
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• v.30 no.4
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• pp.27-34
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• 2021

In this study, the leaching behavior of vanadium (V) was investigated through CaO roasting and sulfuric acid leaching from domestic V-bearing titanomagnetite (VTM). Changes in the phase according to the amount of CaO added and roasting temperature were analyzed. Regardless of the roasting conditions, perovskite (CaTiO₃) was preferred to form. When the CaO content was increased, the calcium ferrite (CaFeO_x) phase was formed; otherwise, ferrite (Fe₂O₃) was preferred. After CaO was roasted, leaching was performed for 6 h with 1M sulfuric acid at 50℃ and a 10% solid-liquid ratio. Results of leaching revealed that when the roasted product was sintered, V was not sufficiently oxidized, and the leaching efficiency decreased. In addition, when the roasting temperature was low, the leaching efficiency of V decreased due to the influence of unreacted excess CaO. To lower the leaching efficiency of iron and titanium in VTM concentrates, suppressing the formation of CaTiO₃ and CaFeO_x was necessary by minimizing the amount of CaO added. Consequently, a leaching efficiency of 86% V, 4.3% Fe, and 6.5% Ti was obtained when the roasted product of 1150℃ and 10 wt% CaO was leached.

• Resources Recycling
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• v.9 no.5
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• pp.22-27
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• 2000

Iron oxide produced form the pickling process at the cold rolling mill in iron & steelmaking industry, use for raw material of electronic an colorant product. Recently, decreasing of the chlorine content in iron oxide is demanded at the market. In this study, under the field test of the spray roaster and the screw conveyer for dechlorination, the experiments of the chlorine content in iron oxide were investigated. From the results of experiment, the chlorine content in iron oxide can be reduced to 1,100 ppm from the spray roaster and, 383 ppm from the screw conveyer.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.4
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• pp.483-488
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• 1998

In order to elucidate the effect of heme compounds on lipid oxidation in roasted and/or reheated mackerel and pacific saury, changes in myoglobin, metmyoglobin, total iron, nonheme iron and heme iron content were measured. Throughout the steps of roasting, heating and reheating, myoglobin content was decteased more rapidly roasted at $180^{\circ}C$ for 20 min in fillet samples than those roasted at $200^{\circ}C$ for 15 min or $220^{\circ}C$ for 10 min. When the skinless samples were roasted at $180^{\circ}C$ for 20 min, about $38\%$ of myoglobin in raw meat were remained. The skinless fillet roasted at the lower temperature resulted the higher level of metmyoglobin due to the reduced myoglobin. Regardless of roasted temperature and time, total iron content was retained the level of raw meat throughout processing. 2 times of nonheme iron content was noted in the skinless fillet samples roasted at $180^{\circ}C$ for 20 min. All samples, heme iron content was decreased much lower by roasted temperature and in absence of skin on fillet. It was decreased about $33\%$ when roasted at $180^{\circ}C$ for 20 min in the skinless fillet in case of pacific saury.