• Title, Summary, Keyword: CaO recovery

Search Result 70, Processing Time 0.034 seconds

Recovery of An, Ag, and Ni from PCB Wastes by CaF2-containing Slag (형우(螢右) 함유(含有) 슬래그 노이(盧理)를 통한 PCB 스크랩으로부터 Au, Ag, Ni의 회수(回收)에 관한 연구(班究))

  • Park, Joo-Hyun
    • Resources Recycling
    • /
    • v.20 no.4
    • /
    • pp.58-64
    • /
    • 2011
  • Recovery of novel metals such as Au, Ag and Ni from wastes PCB was investigated by slag treatments. The CaO-$Al_2O_3$(-$SiO_2$) and CaO-$SiO_2$-$CaF_2$ slags were employed in the present study. The PCB/Cu ratio is recommended to be lower than unity. The use of CaO-$SiO_2$-$CaF_2$ slag provided the more higher yield of Au, Ag and Ni than the CaO-$Al_2O_3$(-$SiO_2$) slag did, which was mainly due to the lower melting point and the viscosity of $CaF_2$-containing slag. The terminal descending velocity of metal droplets in the slag phase increased with decreasing slag viscosity.

Recovery and Characterization of Lactic Acid from Fermentation Broth Using Chemical Precipitation (화학침전을 이용한 발효액의 젖산 회수 및 유기물 특성분석)

  • Lee, Wontae
    • Journal of the Korea Organic Resources Recycling Association
    • /
    • v.26 no.1
    • /
    • pp.47-53
    • /
    • 2018
  • Recovery of lactic acid from fermentation broth using chemical precipitation was investigated with various chemicals. Effects of chemical types, mixing speeds, settling duration, and solvent addition were evaluated to improve the recovery rates of lactic acid. Overall, recovery efficiencies increased as the dosage of chemicals increased. Recovery rate of lactic acid by CaO was higher than those of $Ca(OH)_2$ and $CaCO_3$. Recovery of lactic acid increased by 48% under the optimized reaction conditions which included a mixing speed at 180 rpm, a settling duration of 24 h, and addition of ethanol at 25%(v/v). Practical application needs to consider types and concentrations of other organic acids as well as lactic acid. Based upon the results of fluorescence excitation emission matrix (FEEM), size exclusion chromatography (SEC), characteristics of recovered lactic acid were same as that in the fermentation broth.

Development of Technology for Recovering Valuable Metals in Detoxified Waste Asbestos-Containing Waste (무해화된 폐석면에 함유된 유가금속 회수 기술 개발)

  • Kim, Dong Nyeon;Yang, Dong Hyeon;Kim, Seok Chan
    • Applied Chemistry for Engineering
    • /
    • v.31 no.4
    • /
    • pp.438-442
    • /
    • 2020
  • Studies on the recovery conditions and optimization process for valuable metal recovery through chemical treatment from detoxified asbestos-containing waste composed of calcium silicate, larnite, merwinite, and akermanite were conducted. The main components, Si, Ca, and Mg, of detoxified asbestos-containing waste (DACW) were separated and recovered in the form of SiO2, CaSO4, and Mg(OH)2 compounds, respectively. Each separated component was confirmed through X-ray diffraction (XRD) and inductively coupled plasma spectrometer (ICP) analysis. The recovery conditions for each component were first treating them with an acid to separate SiO2 and subsequently with H2SO4 to recover Ca in the form of sulfate, CaSO4. The remaining Mg was recovered by precipitation with Mg(OH)2 under strong basic conditions. This study suggested that it is possible to convert existing treatment process of asbestos waste by landfill through recovering the components into a resource-recycling green technology.

A study for use a vanadium oxide in steel manufacture (제강 공정중 산화바나듐활용 연구)

  • Choi, Young-Key
    • Journal of environmental and Sanitary engineering
    • /
    • v.24 no.3
    • /
    • pp.55-61
    • /
    • 2009
  • Fe-V is used as raw material of vanadium in the steel making process. The purpose of this study, Fe-V is to replace the $VO_{4}$. So the distribution behavior of vanadium in $VO_{4}$ of the steel investigated. The distribution ratio of the vanadium where potential of the free oxygen ion will increase in slag decreased. When CaO and MgO content which is a basic oxide from CaO-$SiO_2$-FetO-MgOsatd. slag increases, S distribution ratio increases. CaO-$SiO_2$-FetO-MgOsatd. slag better than CaO-$SiO_2$-$Al_2O_3$-MgO slag is the recovery of vanadum and desulfurization.

Optimization of Precipitation Process for the Recovery of Lactic Acid (Lactic acid 회수를 위한 침전공정 최적화)

  • Choi, Kook-Hwa;Chang, Yong-Keun;Kim, Jin-Hyun
    • KSBB Journal
    • /
    • v.26 no.1
    • /
    • pp.13-18
    • /
    • 2011
  • In this study, precipitation process was developed for the recovery of the lactic acid from calcium lactate fermentation broth. Calcium lactate yield was improved by decreasing the solubility of calcium lactate through the addition of ethanol (25%, v/v) as a co-precipitant. The optimal lime type, lime concentration, stirrer speed, precipitation time, temperature, and solvent amount for $Ca(LA)_2$ precipitation were CaO, 0.0175 g/mL, 220 rpm, 24 h, $5^{\circ}C$, ethanol 25% (v/v), respectively. Lactic acid was easily and efficiently recovered from precipitated $Ca(LA)_2$ by adding sulfuric acid ($Ca(LA)_2/H_2SO_4$ molar ratio=1:1). In the model solution of organic acids and fermentation broth, the overall yields of recovered lactic acid were 62% and 55%, respectively, under the aforementioned optimal conditions.

Effects of Sulfuric Acid on the Synthesis of Highly Pure Calcium Borate in the Boron-Containing Brine and Bittern (붕소함유 염수와 간수로부터 고순도 calcium borate를 합성하는 반응에 황산이 미치는 영향)

  • Seo, Hyo-Jin;Kim, Myoung-Jin
    • Journal of Navigation and Port Research
    • /
    • v.39 no.6
    • /
    • pp.523-528
    • /
    • 2015
  • In this study, we investigated the effects of sulfuric acid on the synthesis of calcium borate in the artificial boron-containing brine (bittern) saturated with calcium hydroxide. For the study, we attempted to synthesize calcium borate under various conditions such as reaction temperature, reaction time, and cooling temperature after heating, and then to examine the recovery and purity of the calcium borate according to the presence or absence of sulfuric acid at each condition. The XRD analysis confirmed that, regardless of the presence of sulfuric acid, the calcium borate ($Ca_2B_2O_5{\cdot}H_2O$) was synthesized, while, in the presence of sulfuric acid, the calcium sulfate ($CaSO_4{\cdot}0.5H_2O$) was produced as a by-product. In all the experiments performed by varying the reaction temperature and time, the recovery and purity of the calcium borate without sulfuric acid were observed higher than those with it. The results indicated that the addition of sulfuric acid increased the solubility of the calcium hydroxide, but the calcium sulfate produced as a by-product could decrease the recovery and purity of the calcium borate by preventing the synthesis. In this study, the artificial boron-containing brine (bittern) (500 mg-B/L) was saturated with calcium hydroxide in the absence of sulfuric acid, and then the solution was heated at $80-105^{\circ}C$ for less than 10 minutes to synthesize the calcium borate. The recovery and purity of calcium borate were measured as high as 80 % and 96 %, respectively.

Study on $CaCO_3$ Preparation from MSWI Fly Ash (생활쓰레기 소각(燒却)비산재로부터 $CaCO_3$ 제조(製造)에 관한 연구(硏究))

  • Choi, Woo-Zin;Park, Eun-Kyu
    • Resources Recycling
    • /
    • v.15 no.5
    • /
    • pp.47-51
    • /
    • 2006
  • The total amount of ash generated from the municipal solid waste incineration(MSWI) in Korea was approximately 420,000 tons in 2005 including 68,000 tons of fly ash. Fly ash from MSWI generally contains high amount of CaO (upto ${\sim}50%$) due to the treatment of flue gas by spraying CaO-base materials. Currently, most of fly ash generated is finally ended up with specially designed landfill sites and only less then 20% of fly ash is recycled. In the present work, preparation of $CaCO_3$ from the MSWI ny ash was studied to promote the fly ash recycling. Fly ash obtained from the dust collector in stoker-type MSWI is used to selectively dissolve CaO by using the sugar solution. Then, $CO_2$ gas was passed through the dissolved solution to pro- duce $CaCO_3$ powder. The optimum conditions for CaO dissolution were solid content 10%, reaction time 15 minutes, sugar concentration $10{\sim}15%\;and\;pH\;10.5{\sim}11.0$. The high grade $CaCO_3$ powder was obtained and the experimental conditions are also discussed.

Improvement of Analytical Method of Tricyclazole-and IBP-Combined Dust (Tricyclazole과 IBP 혼합분제의 분석법 개선)

  • Kim, Yoon-Jeong;Nam, Young-Rack;Kim, Jang-Eok
    • Korean Journal of Environmental Agriculture
    • /
    • v.13 no.1
    • /
    • pp.90-97
    • /
    • 1994
  • This experiment was conducted to improve the analytical method of tricyclazole- and IBP-combined dust. When the tricyclazole and IBP active ingadients were analyzed by the official analytical method, their recovery rates were 89.5 and 100%, respectively. A reason of the lower recovery rate in tricyclazole was found to be due to strong binding to the minor inorganic compoments, $Al_2O_3$, $Fe_2O_3$, CaO and MgO, of talc and kaoline. However, addition of 0.2% dimethylamine to extraction solvent for tricyclazole- and IBP-combined dust effectively raised the recovery rate of tricyclazole by providing higher basicity than tricyclazole. We have suggest an improved analytical method which is applicable to effective and simultaneous analysis of the active ingradients of tricyclazole- and IBP-combined dust.

  • PDF

Adsorption of phosphate in water on a novel calcium hydroxide-coated dairy manure-derived biochar

  • Choi, Yong-Keun;Jang, Hyun Min;Kan, Eunsung;Wallace, Anna Rose;Sun, Wenjie
    • Environmental Engineering Research
    • /
    • v.24 no.3
    • /
    • pp.434-442
    • /
    • 2019
  • The present study investigated a novel calcium hydroxide-coated dairy manure-derived biochar (Ca-BC) for adsorption of phosphate from water and dairy wastewater. The Ca-BC showed much higher adsorption of phosphate than that of dairy manure-derived biochar. The Ca-BC possessed mainly the calcium hydroxide and various functional groups resulting in high reactivity between phosphate and calcium hydroxide in the Ca-BC. The adsorption of phosphate onto Ca-BC followed pseudo-second order kinetic and Freundlich isotherm models indicating chemisorptive interaction occurred on energetically heterogeneous surface of Ca-BC. The maximum adsorption capacity of the Ca-BC was higher than those of iron oxide and zinc oxide-coated biochars, but lower than those of CaO- and MgO-coated biochars. However, the Ca-BC showed high reactivity per surface area for adsorption of phosphate indicating importance of surface functionalization of biochar. On the other hand, the adsorption of phosphate in dairy wastewater on Ca-BC was lower than that in water owing to competition between other anions in wastewater and phosphate. Overall, the Ca-BC would be a low cost and effective adsorbent for recovery of phosphate from water and wastewater.

Development of Methane Gas Sensor by Various Powder Preparation Methods

  • Min, Bong-Ki;Park, Soon-Don;Lee, Sang-Ki
    • The Korean Journal of Ceramics
    • /
    • v.5 no.2
    • /
    • pp.125-130
    • /
    • 1999
  • After $SnO_2$ fine powder by precipitation method, Ca as crystallization inhibitor and Pd as catalyst were added to $SnO_2$ raw material by various methods. Thick film device was fabricated on the alumina substrate by mixing ethylene glycol and such mixed powders. The sensing characteristics of the device for methane gas were investigated. The most excellent gas sensing property was shown by the thick film device fabricated by Method 3 in which Ca and Pd doped $SnO_2$ powder is prepared by mixing $SnO_2$ powder, 0.1 wt% Ca acetate and 1 wt% $PdCl_2$ in deionized water and by calcining the mixture, after $Sn(OH)_4$ is dried at $110^{\circ}C$ for 36h. The sensitivity of the sensor fabricated with $SnO_2$-0.1 wt%Ca acetate-1wt%$PdCl_2$ powder heat-treated at $700^{\circ}C$ for 1h was about 86% for 5,000 ppm methane in air at $350^{\circ}C$ of the operating temperature. Response time and recovery were also excellent.

  • PDF