• Resources Recycling
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• v.1 no.1
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• pp.29-36
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• 1992

The extration of vanadium and nickel from heavy oil fly ash was carried out by using water ans sulfuric acid as leaching agent. In the leaching with water, vanadium and nickel were extracted 86% and 88% respectively under pulp density of 25g/l, room temperature and leaching time of 60 minutes, but extraction of vanadium decreased with increasing leaching time. Addition of oxidant decreased the extractions of vanadium and nickel, and roasting of fly ash at temperature higher than $300^{\circ}C$ before water leaching decreased the vanadium extraction to about zero. In the leaching with 1N sulfuric acid, the extractions of vanadium and nickel both increased to 96% and the addition of oxidant did not affect the extraction of these metals.

• Resources Recycling
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• v.32 no.3
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• pp.26-37
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• 2023

Good control of the solution pH and temperature is required to recover vanadium from the water leaching solution of vanadium ore after sodium roasting. However, such adjustments could lead to aluminum-vanadium and sodium-vanadium co-precipitation, which greatly affects the efficiency of vanadium recovery. In this study, a process that can increase the efficiency of vanadium recovery as ammonium metavanadate [NH₄VO₃] and ammonium polyvanadate [(NH₄)₂V₆O₁₆·H₂O] was investigated by examining the characteristics of vanadium-containing aqueous solutions during precipitation. The aluminum content of vanadium-containing water leaching solutions has a great effect on the loss of vanadium when the pH of the aqueous solution is adjusted to 9. Therefore, a process to minimize aluminum leaching is also required. In this study, ~99% or more of vanadium present in vanadium-containing aqueous solutions was precipitated and recovered as NH₄VO₃ by adding 3 equivalents of ammonium chloride relative to the vanadium content at pH 9 and room temperature. (NH₄)₂V₆O₁₆·H₂O was precipitated from the aluminum-vanadium coprecipitates generated during the pH-adjustment of the aqueous solutions to 9 by dissolving the coprecipitate in the solutions at pH 2.5 and controlling their sodium content to 2,000 mg/L or less. Approximately, 98% or more of the available (NH₄)₂V₆O₁₆·H₂O could be precipitated and recovered from a solution with a vanadium content of 2,200 mg/L and a sodium content of 1,875 mg/L at pH 2.5 by adding approximately 3 equivalents of ammonium chloride relative to the vanadium content at 95℃ or higher. The overall process could precipitate and recover, approximately 91% or more of the total vanadium in the water leaching solution as NH₄VO₃ and (NH₄)₂V₆O₁₆·H₂O.

• Resources Recycling
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• v.31 no.2
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• pp.12-19
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• 2022

The study was conducted to develop a vanadium recovery process using reduction pre-treatment in the Vanadium TitanoMagnetite (VTM) The sample for the research was provided by the Gwan-in Mine in Pocheon, Gyeonggi-do. The vanadium content of the sample is 0.54 V₂O₅% and vanadium is concentrated mainly in magnetite and ilmenite. Magnetic separation of the sample can increase vanadium content up to 1.10 V₂O₅%. To increase the vanadium content further, reduction pre-treatment was performed, which is a process of concentrating vanadium present in the iron by reducing iron in magnetite using carbon(C). Based on this reduction pre-treatment, the magnetic separation process was developed, which achieved a vanadium grade of 1.31V₂O₅% and 79.68% recovery. In addition, XRD analysis of the vanadium concentrate before and after reduction and the final vanadium concentrate was performed to confirm the behavior of vanadium by reduction pre-treatment.

• Resources Recycling
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• v.17 no.1
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• pp.38-42
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• 2008

This study was carried out to investigate the solubility of vanadium in ammoniacal solution and precipitation of $NH_4VO_3$ as a function of temperature and addition of ammonia salt. Higher solution temperature is required to get high solubility of vanadium and the vanadium concentration of solution was 16.8g/L at $90^{\circ}C$ with the solution of 20 g/L $(NH_4)_2CO_3$ and 2.5M $NH_4OH$. From this solution, vanadium could be precipitated up to 99.8% with adding 20 g/L $NH_4Cl$, 72 hours settling time at $25^{\circ}C$.

• 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.13 no.4
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• pp.32-38
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• 2004

Recently, Orimulsion (a bitumen-in emulsion) has received increasing attention as an alternative fuel. Orimulsion combusion produces an ash rich in V, Ni and Mg which are processed to recover metals. As a basic study to recover V from Orimulsion ash, physico-chemcial properties and leaching behaviours were investigated. Orimulsion ash was fine size grains ($d_{50}$ 5.9 $\mu\textrm{m}$) with 16% V, 4 % Ni and 9% S. Vanadium was easily leached in water because Orimulsion ash was mainly constituted of metal sulfates. However, the increase of leaching temperature decreased the extraction percentage of vanadium because of hydrolysis of V(V) to vanadium pentoxide. The addition of sulfuric acid could increase the leaching percentage vanadium. In case of alkaline leaching for selective recovery of vanadium, the oxidzing agent such as $H_2$$O_2$ is required to improve the leaching per-centage

• Membrane Journal
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• v.18 no.3
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• pp.241-249
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• 2008

This study is to concentrate vanadium in Jeju groundwater using reverse osmosis processes, and to utilize the concentrate for vanadium water. Groundwater samples were taken from Wahyul, Ayum, and Seogwipo groundwater wells with different in vanadium content each other. Their vanadiuln concentrations were 31.8, 44.5, and 53.0 ppb, respectively. The rejection coefficients of every component in groundwater were increased with the increase of TMP At the TMP of $8 kg_f/cm^2$, the rejection coefficients of vanadium, sodium, potassium, aluminium, iron, and barium were $97.4%{\sim}99.0%,\;97.7%{\sim}97.8%,\;98.0%{\sim}98.3%,\;94.8%{\sim}97.5%,\;88.0%{\sim}96.4.0%$, and $97.9{\sim}98.0%$, respectively. And those of magnesium, calcium, chromium, mauganese, and strontium in three groundwater were more than 99.0% at the same TMP. It was possible that vanadium contents of Wahyul, Ayum and Seogwipo groundwater were concentrated into 58.6, 118.9, and 165.1 ppb, respectively, by 6 stages treatment at the recovery ratio of 15%. And these concentrated water (vanadium water) did not exceed the permissible drinking water standards.

• Resources Recycling
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• v.33 no.3
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• pp.3-11
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• 2024

This study addressed the cost structure of metallurgical plants for vanadium recovery or production, which were previously planned or implemented. Vanadium metallurgy consists of several sub-processes such as such as pretreatment, roasting, leaching, precipitation, and filtration, in order to finally produce vanadium pentoxide. Here, lots of costs should be spent for such plants, in which these costs are largely divided into CAPEX (Capital Expenditure) and OPEX (Operational Expenditure). As a result, the capacities (feed input rates) and vanadium contents are various along the target projects for this study. However, final production rates and grades of vanadium pentoxide showed relatively small differences. In addition, a noticeable correlation is found between capacities and specific operating costs, in that a steadily decreasing trend is described with a non-linear curve with around -0.3 power. Therefore, for the plant capacity below 100,000 tons per year, the specific operating cost rapidly decreases as the capacity increases, whereas the cost remains relatively stable in the range of 0.6 to 1.2 million tons per year of the capacity. From a technical perspective, effective optimization of the metallurgical process plant can be achieved by improving vanadium recovery rate in the pre-treatment and/or roasting-leaching processes. Finally, the results of this study should be updated through future research with on-going field verification and further detailed cost analysis.

• Resources Recycling
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• v.28 no.5
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• pp.42-50
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• 2019

In this study, the precipitation reaction of vanadium and ammonium chloride in aqueous solution was investigated in order to recover vanadium. Ammonium metavanadate having a crystal structure of [$NH_4VO_3$] was precipitated from aqueous solution containing vanadium at pH 9.2 ~ 9.4, and ammonium polyvanadate having a crystal structure of [$(NH_4)_2V_6O_{16}$] was precipitated when the pH of the aqueous solution containing vanadium was adjusted with sulfuric acid. Ammonium polyvanadate [$(NH_4)_2V_6O_{16}$] precipitated at a temperature of $80{\sim}90^{\circ}C$ and pH 2, and at a temperature of $40^{\circ}C$ and pH 6 ~ 8 of aqueous solution. In the acidic region of aqueous solution pH 2, the vanadium content of the aqueous solution should be at least 3,000 mg/L and the precipitation temperature should be maintained at $80^{\circ}C$ or higher in order to obtain a precipitation ratio of 99% or more. When the ammonium vanadate was precipitated in the alkaline region, the vanadium content was more than 10,000 mg/L and the precipitation temperature was maintained at $40^{\circ}C$ to increase the precipitation ratio. Aluminum was not precipitated regardless of the vanadium content and pH of the aqueous solution. However, the iron component reacts with ammonium chloride to precipitate into ammonium jarosite. Therefore, Fe component must be preferentially removed in order to increase the recovery of vanadium.

• Resources Recycling
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• v.25 no.6
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• pp.65-72
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• 2016

We studied a selective recovery condition of vanadium (V) from FALL (Fly Ash Leach Liquor) produced at a fossil fuel power station using heavy oil. By applying a spectroscopy to quantify the V in a sample, we identified a concentration range V interfered by on presence of metals such as Ni, Fe Also, the optimal vanadium precipitation rate according to the amount of 5.0M $NH_3$ loaded to the sample, solution pH and stirring time. As a result of the experiment, the maximum selective recovery ratio of V was achieved to be higher than 91.5% when the stirring duration was less than 1 minute at pH 7.0, and $25^{\circ}C$.