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.

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...

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 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.

scholarly journals Photodegradation of Phenolic Compounds from Water in the Presence of a Pd-Containing Exhausted Adsorbent

2020 ◽  
Vol 10 (23) ◽  
pp. 8440
Author(s):  
Lavinia Lupa ◽  
Laura Cocheci ◽  
Bogdan Trica ◽  
Adina Coroaba ◽  
Adriana Popa
Keyword(s):  
Phenol Degradation ◽  
Magnesium Silicate ◽  
Degradation Process ◽  
Liquid Ratio ◽  
Phenol Solution ◽  
Secondary Sources ◽  
Great Economic Importance ◽  
Phenol Photodegradation ◽  
Cyphos Il 101 ◽  
Solid Liquid

A closed-cycle technology regarding the use of an exhausted Pd-based adsorbent as a photocatalyst in the degradation process of phenol is presented. Pd (II) represents a precious metal of great economic importance. Its obtained from natural sources become more difficult to achieve. Therefore, also considering the regulations of the “circular economy,” its recovery from secondary sources turn out to be a stringent issue in the last years. Pd(II) ions are removed from aqueous solution through adsorption onto Florisil (an inorganic solid support—magnesium silicate) impregnated with Cyphos IL 101 (trihexyl tetradecyl phosphonium chloride). It was observed that the presence of the ionic liquid (IL) in the adsorbent structure doubles the adsorption efficiency of the studied materials. The newly obtained Pd-based photocatalyst was exhaustively characterized and was used in the degradation process of phenol from aqueous solutions. The phenol degradation process was studied in terms of the nature of the photocatalyst used, time of photodegradation and solid: liquid ratio. It was observed that both the presence of IL and Pd lead to an increase in the efficiency of the phenol degradation process. The new Pd-based photocatalyst could be efficiently used in more cycles of phenol photodegradation processes. When is used as a photocatalyst the Florisil impregnated with IL and loaded with 2 mg/g of Pd, a degree of mineralization of 93.75% is obtained after 180 min of irradiation of a phenol solution having a concentration of 20 mg/L and using a solid:liquid ratio = 1:1.

Research on Ethanol Production by Biological Fermentation of Potato Pulp

2013 ◽  
Vol 805-806 ◽  
pp. 281-285
Author(s):  
Zhong Xu
Keyword(s):  
Chemical Composition ◽  
Ethanol Production ◽  
Production Rate ◽  
Liquid Ratio ◽  
Fermentation Time ◽  
Potato Pulp ◽  
Fermentation Temperature ◽  
Ethanol Production Rate ◽  
Solid Liquid

Bioconversion of potato pulp to fuel ethanol, analysing the potato pulp chemical composition and determining the potato pulp in the role of microorganism produce ethanol under the best conditions is the major research. An analysis of the chemical composition of potato pulp showed that : the basic ingredients are Protein (9.72%), Starch (25.52%), Cellulose (17.90%). The effects of ethanol production rate of solid-liquid ratio, fermentation temperature, inoculumconcertration, fermentation time. The results showed that: the best conditions producting ethanol from potato pulp obtained by single factor experiments are: solid-liquid ratio: 1:15, fermentation temperature: 35°C, inoculumconcertration: 3mL, fermentation time: 20h. Under this occasion, the ethanol production rate was 0.183mL·g-1.

The Influence Factors of Compressive Strength and Production of Mineral Polymer of Aluminum Rocks in Xiuwen County, Guizhou Province, China

2013 ◽  
Vol 690-693 ◽  
pp. 1086-1090
Author(s):  
Jie Zhang ◽  
Qiong Qiong Li ◽  
Yu Qiang Xiong
Keyword(s):  
Compressive Strength ◽  
Water Glass ◽  
Mineral Water ◽  
Raw Materials ◽  
Influence Factors ◽  
Polymer Materials ◽  
Guizhou Province ◽  
Liquid Ratio ◽  
Alkaline Activator ◽  
Solid Liquid

Aluminous rocks from Xiuwen County, Guizhou are the main raw materials, mixed some kaolin mineral. Water glass and alkaline activators are used to product polymer materials, the main experimental indicators are the compressive strength. Here, the studies on amount of water glass and alkaline activator, solid-liquid ratio, amount of kaolin and effects on compressive strength of Geopolymer have been proceeded respectively. The result shows that: the highest compressive strength of geopolymers is17.94 Mpa, with aluminous rock 40g, solid-liquid ratio 2.2, water glass12g and alkali activator 2.01g, as well as kaolin 18.02g.

scholarly journals Modeling of Total Phenolic contents in Various Tea samples by Experimental Design Methods

2018 ◽  
Vol 16 (1) ◽  
pp. 738-744
Author(s):  
Nuraniye Eruygur ◽  
Nazire Gulsah Kutuk Dincel ◽  
Nursah Kutuk
Keyword(s):  
Phenolic Compounds ◽  
Experimental Design ◽  
Green Tea ◽  
Total Phenolic ◽  
Phenolic Substance ◽  
Extraction Temperature ◽  
Liquid Ratio ◽  
Polyphenol Content ◽  
Positive Effects ◽  
Solid Liquid

AbstractTea, from the old ages to the day, is widely consumed both for enjoyment and health care due to its positive effects. The consumption of these products is increasing day by day as a result of the clear presentation of the fact that tea contains high amount of antioxidant substances (such as phenolic compounds), which is important in prevention and treatment of diseases. Tea beverage is a very important source of polyphenols. In this study, phenolic content and antioxidant capacity of different tea species were calculated by modeling with experimental design method. In the experimental part, polyphenol content was determined using the Folin-Ciocalteu method. The total amount of phenolic substance content was examined by Box-Behnken design and response surface method on black tea, green tea and white tea on different extraction temperature, extraction time and solid / liquid ratio. Solid / liquid ratio was found to be the most important parameter in terms of polyphenol content extraction from different tea samples. The highest polyphenol amount (411.762 mg gallic acid / mL) was found in green tea. To the best of our knowledge, this is the first data presenting comparatively study the effect of extraction condition on amounts of phenolic compounds from different tea samples.

scholarly journals Optimisation of the Conversion and Extraction of Arctigenin From Fructus arctii Into Arctiin Using Fungi

2021 ◽  
Vol 12 ◽  
Author(s):  
Zheng Lu ◽  
Bin He ◽  
Jie Chen ◽  
Li-Jun Wu ◽  
Xia-Bing Chen ◽  
...  
Keyword(s):  
Loss Rate ◽  
Aspergillus Awamori ◽  
Liquid Volume ◽  
Average Yield ◽  
Liquid Ratio ◽  
Fermentation Time ◽  
Intestinal Microbes ◽  
Carbon And Nitrogen ◽  
Solid Liquid ◽  
Further Development

Fructus arctii is commonly used in Chinese medicine, and arctiin and arctigenin are its main active ingredients. Arctiin has low bioavailability in the human body and needs to be converted into arctigenin by intestinal microbes before it can be absorbed into the blood. Arctigenin has antiviral, anti-inflammatory, and anti-tumour effects and its development has important value. In this study, we used external microbial fermentation with Aspergillus awamori and Trichoderma reesei to process and convert arctiin from F. arctii powder into arctigenin, hence increasing its bioavailability. We developed a fermentation process by optimising the carbon and nitrogen source/ratio, fermentation time, pH, liquid volume, inoculation volume, and substrate solid-liquid ratio. This allowed for an arctiin conversion rate of 99.84%, and the dissolution rate of the final product was 95.74%, with a loss rate as low as 4.26%. After the fermentation of F. arctii powder, the average yield of arctigenin is 19.51 mg/g. Crude fermented F. arctii extract was purified by silica gel column chromatography, and we observed an arctigenin purity of 99.33%. Our technique effectively converts arctiin and extracts arctigenin from F. arctii and provides a solid basis for further development and industrialisation.

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