• Title/Summary/Keyword: $HNO_3$

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Nitric-Acid Pulping of Municipal Wastepapers and its Spent-Liquor Utilization for Fertilizers(I) -Study on the Nitric-Acid Pulping Conditions of OCC Pulp- (도시 폐휴지의 질산 펄프제조와 펄프폐액의 입상 비료화 기술개발(I) -폐골판지 상자(OCC)의 질산 펄프제조 조건-)

  • 임기표;위승곤;김창래;양정훈
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.32 no.4
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    • pp.74-80
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    • 2000
  • A series of studies on nitric-acid pulping of municipal recycled waste papers were carried out to substitute the bleached chemical pulp imported for producing printing paper as well as to use its solidified spent-liquor as fertilizer. The first experiment was carried out to find the optimum treatment conditions such as pulp consistency, nitric acid charge and temperature in $HNO_3$-alkali pulping process. The results obtained were as follows: 1. Some selective delignification of OCC pulp was conducted by $HNO_3$-alkali process. The higher the temperature and concentration of nitric acid, the lower the pulp yield and kappa number of treated pulp. while its brightness was increased. 2. The higher consistency required the stronger mixing in case of more than 5% pulp. 3. In the laboratory, the suitable $HNO_3$-treating condition seemed to be less than 6% consistency, lower than 500% $HNO_3$charge on pulp and lower than $100^{\circ}C$ in cooking temperature. 4. The spent liquor with 1.77% N-content seemed to be slow-release nitrogen fertilizer suitable for agriculture.

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Recovery of Yttrium from the Sludge Generated in Recycling Process of the Obsolete CRT (폐CRT의 재활용 공정에서 발생한 슬러지로부터 Y의 회수)

  • 전준미;이재천;정진기;김남철
    • Resources Recycling
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    • v.10 no.6
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    • pp.22-28
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    • 2001
  • A study on the recovery of yttrium was conducted using the phosphor sludges generated in the recycling process of obsolete CRTs. Yttrium was leached by HCl and $HNO _3$. The leaching efficiency of yttrium was extensively investigated in terms of acid concentration, leaching temperature and time, and pulp density. Yttrium and lead was recovered from leaching solutions also by precipitation method. The leaching behavior of yttrium was similar in both acids. The leaching efficiency of yttrium for both acids increased with time at the conditions of 3.0M, $90^{\circ}C$, and 280 g/L of pulp density. After 40 minutes, it was saturated to 93% and 90% for HCl and HNO$_3$respectively. Yttrium was recovered from leaching acid solution by the addition of $H_2$$C_2$$O_4$while lead was removed as $PbSO_4$by $Na_2$ $SO_4$.

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Preparation of AC/TiO2 Composites from Activated Carbon Modified by HNO3 and Their Photocatalytic Activity

  • Chen, Ming-Liang;Oh, Won-Chun
    • Carbon letters
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    • v.8 no.2
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    • pp.108-114
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    • 2007
  • In this work, activated carbon (AC) after $HNO_3$ modification was used as the support during the production of supported $TiO_2$ to increase the high deposition efficiency and the photocatalytic activity. The results of $N_2$ adsorption showed that the BET surface area of samples decreased with an increasing of the concentration of $HNO_3$ due to the penetration of $TiO_2$. From XRD data, a single crystal structure of anatase peak was observed in diffraction patterns for the AC coated with titanium complexes. From the SEM results, almost all particles were aggregated with each other at the carbon surface and AC was covered with $TiO_2$ particles in all of the samples. The EDX spectra show the presence of C, O, Ti and other elements. It was also observed a decreasing of amount of C content with increasing Ti and O content from the EDX. The results of FT-IR revealed that the modified AC contained more surface oxygen bearing groups than that of the original AC. The effect of surface acidity and basity calculated from Boehm titration method was also evaluated from correlations as a function of NaOH, $NaHCO_3$, and $Na_2CO_3$ uptake. The surface modification of AC by $HNO_3$ leads to an increase in the catalytic efficiency of AC/$TiO_2$ catalysts, and the catalytic efficiency increases with increasing of $HNO_3$ concentration.

Reductive Dissolution of Spinel-Type Iron Oxide by N2H4-Cu(I)-HNO3

  • Won, Hui Jun;Chang, Na On;Park, Sang Yoon;Kim, Seon Byeong
    • Journal of the Korean Ceramic Society
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    • v.56 no.4
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    • pp.387-393
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    • 2019
  • A N2H4-Cu(I)-HNO3 solution was used to dissolve magnetite powders and a simulated oxide film on Inconel 600. The addition of Cu(I) ions to N2H4-HNO3 increased the dissolution rate of magnetite, and the reaction rate was found to depend on the solution pH, temperature, and [N2H4]. The dissolution of magnetite in the N2H4-Cu(I)-HNO3 solution followed the contracting core law. This suggests that the complexes of [Cu+(N2H4)] formed in the solution increased the dissolution rate. The dissolution reaction is explained by the complex formation, adsorption of the complexes onto the surface ferric ions of magnetite, and the effective electron transfer from the complexes to ferric ions. The oxide film formed on Inconel 600 is satisfactorily dissolved through the successive iteration of oxidation and reductive dissolution steps.

Wet Etch Characteristics of Magnetic Thin Films (자성 박막의 습식 식각 특성)

  • 변요한;정지원
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.2
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    • pp.105-109
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    • 2002
  • The wet etching characteristics of magnetic materials such as NiFe and CoFe were investigated in terms of etch rate and etch profile by using variouus etching solutions (etchants). Among the various etching solutions, HNO$_3$, HCl, and H$_2$SO$_4$were selected for the etching of magnetic materials and showed distinct results. In the case of NiFe films, faster etch rate were obtained with HNO$_3$solution. When NiFe films ere etched with HCl solution, white etch residues were found on the surface of etched films. From FEAES analysis of these etch residues, they were proved to be by-product from the reaction of NiFe with Cl element. CoFe thin films showed the similar trend to the case of NiFe films. They were etched fast in HNO$_3$ solution while Chl solution represented slow etching. The etch profiles of CoFe films showed smooth etch profile but revealed the partial etching around the patterns in HNO$_3$solution of relatively high concentration. It was observed that the etched surface was clean and smooth, and that white etch residues were also remained on the etched films.

Extraction behaviors of platinum group metals in simulated high-level liquid waste by a hydrophobic ionic liquid bearing an amino moiety

  • Wu, Hao;Kim, Seong-Yun;Takahashi, Tadayuki;Oosugi, Haruka;Ito, Tatsuya;Kanie, Kiyoshi
    • Nuclear Engineering and Technology
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    • v.53 no.4
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    • pp.1218-1223
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    • 2021
  • A hydrophobic ionic liquid including an amino moiety ([DiOcAPmim][NTf2]) was synthesized. Its extraction behaviors towards Pd(II), Ru(III), Rh(III) were investigated in nitric acid aqueous solution as a function of contact time, effect of concentration of nitric acid, effect of temperature, and effect of co-existing metal ions. The extraction kinetics of Pd(II) was fairly fast and extraction equilibrium can be attained within only 5 min under the [HNO3] = 2.05 M. When [HNO3]< 1 M, the extraction percentage of Pd(II), Ru(III), Rh(III) were all above 80%. When [HNO3] reached 2 M, all of the extraction percentage decreased and in an order of Pd(II)>Ru(III)>Rh(III). When [HNO3]> 2 M, the extraction performance gradually recovered. The effect of temperature can slightly affect the extraction performance of Pd(II). Furthermore, in simulated high-level liquid waste, [DiOcAPmim][NTf2] showed a better preference towards Pd(II) under the interference of various other co-existing metal ions.

Study on Passive Layer Characteristics of Chemically Passivated Duplex Stainless Steel (화학적 부동태 처리에 따른 듀플렉스 스테인리스 강의 피막 특성에 관한 연구)

  • Jang, Heui-Un;Lee, Jung-Hoon;Kim, Yong-Hwan;Chung, Won-Sub
    • Journal of the Korean institute of surface engineering
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    • v.45 no.6
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    • pp.219-225
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    • 2012
  • The aim of the present study was to investigate the corrosion resistance and characteristics of passive layer between naturally passivated and chemically passivated duplex stainless steel, UNS S31803 (EN 1.4462) using CPT, XPS, and EIS. The treatment of $HNO_3$(II) and $HNO_3$(III) in ASTM A 967 was applied. In case of chemically passivated specimen, CPT of $HNO_3$(II) and $HNO_3$(III) were higher than that of naturally passivated specimen. In addition, from XPS results, the protectiveness index (Cr/(Fe+Cr)) of chemically passivated specimens was also higher than that of naturally passivated specimen. The reason for this result is considered due to post-cleaning treatment in chemical passivation process, that is, immersion in $Na_2Cr_3O_7$ solution. The fact that $HNO_3$(II) passivation treatment showed the highest film resistance and 'n', which is exponent related with constant phase element (CPE) of passivation film, was in good agreement with results of CPS and XPS. The chemical passivation treatment was an effective method to improve corrosion resistance of duplex stainless steel.

Adsorption Characteristics of Benzene and MEK on Surface Oxidation Treated Adsorbent -Surface Oxidation by HNO3, H2SO4 and (NH4)2S2O8- (표면산화 처리된 흡착제의 Benzene 및 MEK 흡착 특성 - HNO3, H2SO4 및 (NH4)2S2O8에 의한 표면산화-)

  • Shim, Choon-Hee;Lee, Woo-Keun
    • Journal of Korean Society for Atmospheric Environment
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    • v.22 no.1
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    • pp.25-33
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    • 2006
  • The objective of this research is to improve the adsorption capacity of adsorbent made from MSWI (Municipal Solid Waste Incinerator) fly ash by surface oxidation. Used oxidation agents were $HNO_{3}$, $H_{2}SO_{4}$ and $(NH_{4})_{2}S_{2}O_{8}$. These agents can modify the surface property of an adsorbent such as specific surface area, pore volume, and functional group. The surface structure was studied by BET method with $N_{2}$ adsorption. The acid value and base value were determined by Boehm's method. The adsorption properties were investigated with benzene and MEK (Methylethylketone). According to the results, the specific surface area of the adsorbent was increased from 309.2 $m^{2}$/g to 553.2 $m^{2}$/g by $HNO_{3}$ oxidation. But $H_{2}SO_{4}$ and $(NH_{4})_{2}S_{2}O_{8}$ oxidation was decreased slightly. After Oxidation, surface acid value increased, but base value decreased. FAA-N shows the highest acid value. The content of oxygen increased greatly and oxygen group was created on the adsorbent surface. The surface oxidation improved the adsorbing capacity for MEK. The amount of adsorbing MEK was increased from 189 $m^{2}$/g to 639 $m^{2}$/g by $HNO_{3}$ oxidation.