Extraction of Tungsten and Vanadium from the Spent SCR Catalyst by High Pressure Alkaline Leaching Method

2018 ◽  
Vol 913 ◽  
pp. 954-960 ◽  
Author(s):  
Jia Peng Chen ◽  
Li Wen Ma ◽  
Ming Xing Cao ◽  
Xiao Li Xi
Keyword(s):  
High Pressure ◽  
Catalytic Reduction ◽  
Sodium Hydroxide Solution ◽  
Liquid Ratio ◽  
Alkaline Leaching ◽  
Scr Catalyst ◽  
Solid Ratio ◽  
Alkali Leaching ◽  
Solid Liquid ◽  
Leaching Efficiency

Tungsten and vanadium are efficiently extracted from honeycomb-type spent selective catalytic reduction (SCR) catalyst by using a high pressure alkali leaching method. Theoretical thermodynamics calculation indicates that WO3and V2O5are soluble in sodium hydroxide solution, proving that the extraction of Wand V from the spent SCR catalyst by high pressure alkaline leaching is feasible. The effects of NaOH concentration, leaching temperature and time, liquid-solid ratio and stirring speed on leaching efficiency of W and V are systematically investigated. The leaching efficiency of W and V is 94.3% and 91.2%, respectively, under the optimal conditions: the NaOH concentration of 2mol/L, the leaching temperature 463.5 K, the reaction time 3 h, solid-liquid ratio 0.1 g/ml, the stirring speed of 400 r/min. The TiO2residue is in anatase crystalline phase.

scholarly journals Study on the Oxidative Leaching of Uranium from the Lignite in the CO32-/HCO3- System

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Y. Ning ◽  
Y. Li ◽  
Y. Zhang ◽  
P. Tang
Keyword(s):  
Yunnan Province ◽  
Reaction Model ◽  
Second Order Reaction ◽  
Liquid Ratio ◽  
Uranium Leaching ◽  
Pseudo Second Order ◽  
Oxidative Leaching ◽  
Solid Liquid ◽  
Leaching Efficiency ◽  
Alcoholic Hydroxyl

Na2CO3/NaHCO3 mixtures with different oxidants were used to leach uranium in the lignite which was obtained from Lincang, Yunnan province. The experimental results showed that the optimal solid/liquid ratio and CO32-/HCO3- ratio for uranium leaching were 1 : 20 (g/mL) and 2 : 1, respectively. With the increase of carbon concentration from 0.1 mol/L to 1.1 mol/L, the leaching efficiency of uranium increased from 14.64% to 42.39% after 6 h leaching. The oxidants could significantly enhance the uranium leaching efficiency, which was up to 72.23% by injecting O2 at 1.5 L/min after 12 h leaching. The oxidative leaching process of uranium from the lignite was better fitted to the pseudo-second-order reaction model. The sequential extraction results illustrated that the oxidants could effectively enhance the leaching of organic matter bound uranium in the lignite, which was decreased from 76.86 mg/kg to 9.00 mg/kg by injecting O2. The infrared spectrum analysis demonstrated that the corresponding transmittance at about 3197 cm−1 was prominently reduced after the oxidative leaching, which intimated that the phenolic and alcoholic hydroxyl might be the main functional groups combined with uranium in the lignite.

The Solubility of Phosphogypsum and Recovery of Heavy and Radioactive Elements

2020 ◽  
Vol 38 (10A) ◽  
pp. 1470-1480
Author(s):  
Waleed T. Rashid ◽  
Israa A. Alkadir ◽  
Moayyed G. Jalhoom
Keyword(s):  
High Mobility ◽  
Major Elements ◽  
Radioactive Elements ◽  
Liquid Ratio ◽  
Phosphate Fertilizers ◽  
Negative Effect ◽  
Temperature Ranges ◽  
Solid Liquid ◽  
Positive Effect ◽  
Leaching Efficiency

The essential purpose of this paper is to illustrate and inspect the leaching characteristics of Iraqi Phosphogypsum (PG). The paper presents the results of the dissolution characteristics of heavy and radioactive elements from PG, which is a by-product result from the industry of phosphate fertilizers. Leachability of heavy and radioactive elements in deionized water that has been inspected under various states of leaching, including solid/liquid ratio (10, 20 and 50 /1g/L) and temperatures (25, 45 and 85 °C), with constant other parameters such as string speed (300 rpm) and contact time (60 minutes). For the most analysis elements, the progressive release of the metals, in addition to the major elements reflects high mobility.  The mobility of trace metals in PG has been generally classified into three main degrees: (1) high mobility elements such as Pb, Zn, Mn, and Cr; (2) moderate mobility elements such as Sr, V, Ba,Y,Hg, K and Ni; and (3)l ow mobility elements like Ca,Cu,Fe, and Ag. The maximum concentrations of the most of the metals were attained from a leaching state of 10/1g/L. Regarding temperature, the experimental results revealed that the PG solubility to leaching out elements increases noticeably as the applied temperature ranges from 25 to 45 °C; after this degree, the leaching efficiency decreases. Chloride had a positive and negative effect on the solubility of phosphorus. Calcium chloride had an adverse effect on solubility and observed reduced solubility with increased chloride. While the positive effect of sodium and magnesium chloride was observed, the solubility...

Process Optimization of Hemicelluloses Lye Extraction from Sugarcane Bagasse

2012 ◽  
Vol 581-582 ◽  
pp. 1206-1212 ◽  
Author(s):  
Li Jun Wang ◽  
Xin Liang Liu ◽  
Meng Ling Weng ◽  
Zhou Jun Li ◽  
Fu Sheng Wu ◽  
...  
Keyword(s):  
Raw Materials ◽  
Extraction Process ◽  
Extraction Yield ◽  
Process Conditions ◽  
Liquid Ratio ◽  
Solid Ratio ◽  
Surface Method ◽  
Alkali Consumption ◽  
Effects Of Temperature ◽  
Solid Liquid

Sugarcane bagasses were used as raw materials to produce the hemicelluloses, and the effects of temperature, alkali consumption, time and liquid to solid ratio on the extraction yield of hemicelluloses were investigated. Through the analysis of the response surface method, results were concluded that the best extraction process conditions were as follows: NaOH concentration 10.60%, extraction time 4.34 h, solid-liquid ratio 1:40.59, actual extraction rate is 31.486%, corresponding to the model prediction 31.4447% basically.

scholarly journals Optimization of Silicon Leaching for White Carbon Black Preparation from Vanadium-Extraction Residue Using Response Surface Methodology

2020 ◽  
Vol 71 (8) ◽  
pp. 206-219
Author(s):  
Shun Wang ◽  
Shenxu Bao ◽  
Yimin Zhang ◽  
Yizhong Yuan
Keyword(s):  
High Pressure ◽  
Response Surface Methodology ◽  
Carbon Black ◽  
Response Surface ◽  
Regression Equation ◽  
Mass Ratio ◽  
Solid Ratio ◽  
Vanadium Extraction ◽  
Alkali Leaching ◽  
Leaching Parameters

Vanadium-extraction residue (VER) is rich in silicon and the high temperature and high pressure alkali leaching can be used to prepare white carbon black (WCB). The effects of the mass ratio of alkali to slag, liquid-solid ratio, reaction temperature and reaction time on the silica leaching ratio were investigated. Response surface methodology was used to analyze the interaction of these main leaching parameters and the final regression equation can be obtained. By using the regression equation, the leaching schemes can be designed as the maximum leaching ratio of silica was set, thereby the optimal leaching parameters also can be obtained to reduce the leaching cost. Repeated experiments showed that the optimized leaching ratio can reach 95.26% which was just lower the predicted value by 2.17%, indicating that the regression equation was reliable to be used to optimize the leaching process. The WCB product with specific surface area of 105.1 m2/g was verified by XRD and FTIR.

The process of vanadium migration and silicon extraction by alkaline leaching from high silicon stone coal under reduction conditions

2019 ◽  
Vol 116 (3) ◽  
pp. 313
Author(s):  
Hao Wu ◽  
Yali Feng ◽  
Heng Zhang ◽  
Haoran Li
Keyword(s):  
Hydrazine Hydrate ◽  
Mass Fraction ◽  
Optimal Operation ◽  
Vanadium Concentration ◽  
Alkaline Leaching ◽  
Stone Coal ◽  
Solid Ratio ◽  
Operation Conditions ◽  
Reducing Conditions ◽  
Alkali Leaching

It is difficult to utilize stone coal with a vanadium grade of below 0.7%. With the aim of effectively utilizing the silicon and vanadium in stone coal, the vanadium concentration and silicon extraction processes by alkaline leaching under reducing conditions were investigated. The effect of NaOH mass fraction, temperature and the amount of hydrazine hydrate on the leaching process was researched. Moreover, the laws of phase transformation and the migration process of vanadium were revealed. The results show that the dissolution of quartz resulted in the exposure of muscovite and goldmanite, but the phase of muscovite and goldmanite was not damaged. Under the optimal operation conditions (25% mass fraction of NaOH, liquid-solid ratio 2:1 at 200 °C for 4 hours), 90.14% of silicon was removed. At the same time, the modulus of sodium silicate product reached 1.88 and the content of V2O5 enriched from 0.5% to 2.51%. In addition, V(IV) was partially reduced to V(III) by adding hydrazine hydrate in an amount of 10% by mass. V(IV) migrated from the liquid phase to the alkali leaching slag, and the recovery of vanadium increased from 89.48% to 94.43%. All the obtained results suggest an efficient process for separation and extraction of vanadium and silicon.

scholarly journals Beneficiation of phosphate-siliceous slates via acetic acid

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yerkebulan Raiymbekov ◽  
Uilesbek Besterekov ◽  
Perizat Abdurazova ◽  
Ulzhalgas Nazarbek ◽  
Galiya Kambarova ◽  
...  
Keyword(s):  
Activation Energy ◽  
Acetic Acid ◽  
Dissolution Time ◽  
Diffusion Region ◽  
Low Grade ◽  
Optimum Conditions ◽  
Liquid Ratio ◽  
Solid Ratio ◽  
Working Parameters ◽  
Solid Liquid

Abstract Low grade phosphate-siliceous slates dump samples (about 11.98% P2O5) from Zhanatas deposit, Karatau basin, Kazakhstan were subjected to upgrading in the present study. The suggested upgrading route was to get rid of most of the inorganic carbonates via leaching using organic acids like acetic acid. The effect of leaching temperature, dissolution time, and solid/liquid ratio were studied as the main determental working parameters. It was concluded that a concentrate product containing about 21% P2O5 was produced after leaching with acetic acid at optimum conditions: 30 C0, 15 min, and 3:1 liquid/solid ratio. The calculated apparent activation energy of the leaching process showed that the process took place in the intra-diffusion region.

scholarly journals A hydrometallurgical process for the recovery of cerium from Khuren khad ore

2019 ◽  
pp. 32-37
Author(s):  
Sandagdorj N ◽  
Enerel B ◽  
Ching-Hwa Lee ◽  
Gankhuyag E ◽  
Terbish N
Keyword(s):  
Recovery Efficiency ◽  
Hydrometallurgical Process ◽  
Liquid Ratio ◽  
Precipitation Product ◽  
Solid Liquid ◽  
Leaching Efficiency

This study presents the recovery of cerium (Ce) from Khuren Khad ore by using the hydrometallurgical process. Several methods of leaching and precipitation were employed to investigate the recovery efficiency of Ce from the ore. According to the result, it is 4.8% of Ce contained in this ore sample. The best result of this study reveals that 100% Ce leaching efficiency can be obtained under leaching conditions of 6N HCl at a temperature of 70° C and 5g/50mL solid/liquid ratio and 3h. Further, 99.60% precipitation recovery of Ce was achieved with NaHCO3 at an interval of 24 hours. After leaching and precipitation, the concentration of Ce was enriched from 4.8% of Khuren Khad ore to 33.09% of precipitation product.

Study of Leaching Zinc from Difficult Dealt Zinc Oxide Ore with High Silicon in the Alkali

2015 ◽  
Vol 1120-1121 ◽  
pp. 105-109 ◽  
Author(s):  
Yong Jia LI ◽  
Da Jin Yang
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
Influencing Factors ◽  
Reaction Temperature ◽  
Alkali Concentration ◽  
Leaching Tests ◽  
Solid Ratio ◽  
Alkali Leaching ◽  
Leaching Condition ◽  
Leaching Efficiency

In this paper, the influencing factors in the process of alkali leaching of refractory zinc oxidize ores were studied. The influence of the particle size, reaction temperature, leaching time, alkali concentration and liquid-solid ratio on the leaching efficiency of zinc were investigated via leaching tests. The results indicate that the particle size has little influence on the leaching efficiency of zinc while the influences of other factors are larger. The optimal leaching condition is: the reaction temperature is 80 °C, the alkali concentration is 4.5 mol/L, and the leaching time is 1.5 h as well as the liquid- solid ratio is 10:1. In such conditions, the leaching efficiency can reach 82.22%.

Aqueous Extraction of Chinese Tallow Seeds Oil

2012 ◽  
Vol 608-609 ◽  
pp. 328-332
Author(s):  
Wen Ma ◽  
Yu Huan Liu ◽  
Roger Ruan ◽  
Xiang Mei Jiang ◽  
Yun Pu Wang ◽  
...  
Keyword(s):  
High Pressure ◽  
Extraction Method ◽  
Ph Value ◽  
Oil Extraction ◽  
Liquid Ratio ◽  
Microwave Assisted ◽  
Pressure Steam ◽  
Aqueous Oil Extraction ◽  
Steam Processing ◽  
Solid Liquid

three oil extraction ways of microwave assisted, conventional and high-pressure oil extraction are compared, we select the high-pressure as the aqueous oil extraction method to carry on the experimental study of the relevant technology and discuss the solid-liquid ratio, baking time, baking temperature, pH value and high-pressure steam processing time on oil yield.

scholarly journals Preparation and Characterization of the Sulfur-Impregnated Natural Zeolite Clinoptilolite for Hg(II) Removal from Aqueous Solutions

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 217
Author(s):  
Marin Ugrina ◽  
Martin Gaberšek ◽  
Aleksandra Daković ◽  
Ivona Nuić
Keyword(s):  
Chemical Modification ◽  
Aqueous Solutions ◽  
Specific Surface ◽  
Surface Area ◽  
Natural Zeolite ◽  
Contact Time ◽  
Liquid Ratio ◽  
X Ray ◽  
Solid Liquid

Sulfur-impregnated zeolite has been obtained from the natural zeolite clinoptilolite by chemical modification with Na2S at 150 °C. The purpose of zeolite impregnation was to enhance the sorption of Hg(II) from aqueous solutions. Chemical analysis, acid and basic properties determined by Bohem’s method, chemical behavior at different pHo values, zeta potential, cation-exchange capacity (CEC), specific surface area, X-ray powder diffraction (XRPD), scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), as well as thermogravimetry with derivative thermogravimetry (TG-DTG) were used for detailed comparative mineralogical and physico-chemical characterization of natural and sulfur-impregnated zeolites. Results revealed that the surface of the natural zeolite was successfully impregnated with sulfur species in the form of FeS and CaS. Chemical modification caused an increase in basicity and the net negative surface charge due to an increase in oxygen-containing functional groups as well as a decrease in specific surface area and crystallinity due to the formation of sulfur-containing clusters at the zeolite surface. The sorption of Hg(II) species onto the sulfur-impregnated zeolite was affected by the pH, solid/liquid ratio, initial Hg(II) concentration, and contact time. The optimal sorption conditions were determined as pH 2, a solid/liquid ratio of 10 g/L, and a contact time of 800 min. The maximum obtained sorption capacity of the sulfur-impregnated zeolite toward Hg(II) was 1.02 mmol/g. The sorption mechanism of Hg(II) onto the sulfur-impregnated zeolite involves electrostatic attraction, ion exchange, and surface complexation, accompanied by co-precipitation of Hg(II) in the form of HgS. It was found that sulfur-impregnation enhanced the sorption of Hg(II) by 3.6 times compared to the natural zeolite. The leaching test indicated the retention of Hg(II) in the zeolite structure over a wide pH range, making this sulfur-impregnated sorbent a promising material for the remediation of a mercury-polluted environment.

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