scholarly journals Cleaner Extraction of Lead from Complex Lead-Containing Wastes by Reductive Sulfur-Fixing Smelting with Low SO2 Emission

Minerals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 119 ◽  
Author(s):  
Yun Li ◽  
Shenghai Yang ◽  
Wenrong Lin ◽  
Pekka Taskinen ◽  
Jing He ◽  
...  
Keyword(s):  
Molten Salt ◽  
Process Conditions ◽  
Optimum Conditions ◽  
Optimal Process ◽  
So2 Emission ◽  
One Step ◽  
Lead Bullion ◽  
Sulfur Fixation

A novel and cleaner process for lead and silver recycling from multiple lead-containing wastes, e.g., lead ash, lead sludge, lead slag, and ferric sludge, by reductive sulfur-fixing smelting was proposed. In this process, coke and iron-containing wastes were employed as reductive agent and sulfur-fixing agent, respectively. A Na2CO3-Na2SO4 mixture was added as flux. The feasibility of this process was detected from thermodynamic and experimental perspectives. The influence of Fe/SiO2 and CaO/SiO2, composition of the molten salt, coke addition, smelting temperature, and smelting time on direct Pb recovery and sulfur-fixation efficiency were investigated. The optimal process conditions were determined as follows: WCoke = 15% WPb wastes, W Na 2 CO 3 / W Na 2 SO 4 = 0.7/0.3, Fe/SiO2 = 1.10, CaO/SiO2 = 0.30, smelting temperature 1200 °C, and smelting time 2 h, where W represents weight. Under these optimum conditions, 92.4% Pb and 98.8% Ag were directly recovered in crude lead bullion in one step treatment, and total 98.6% sulfur was fixed. The generation and emissions of SO2 can be avoided. The main phases in ferrous matte obtained were FeS, NaFeS2, Fe2Zn3S5, and a little entrained Pb. The slag was a FeO-SiO2-CaO-Na2O quaternary melt.

Study on Extracting Potassium from Potassium Feldspar with Molten Salt Leaching Method

2012 ◽  
Vol 524-527 ◽  
pp. 1078-1081
Author(s):  
Jian Guo Song ◽  
Xin Zhi Wang ◽  
Shao Dan Xiao ◽  
Wei Liu
Keyword(s):  
Reaction Time ◽  
Molten Salt ◽  
Potassium Feldspar ◽  
Process Conditions ◽  
Temperature Reaction ◽  
Optimal Process ◽  
Potash Feldspar ◽  
Salt Leaching ◽  
Effects Of Temperature

This article aims to study the technology of extracting potassium from potassium feldspar with molten salt leaching method and to analyze the effects of temperature, reaction time and other factors on extracting potassium, concluding the optimal process conditions of extracting potassium with molten leaching method from potash feldspar.

scholarly journals Degradation of Landfill Leachate Using UV-TiO2 Photocatalysis Combination with Aged Waste Reactors

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 946
Author(s):  
Chunlian Wang ◽  
Xiaojie Sun ◽  
Huijun Shan ◽  
Hongxia Zhang ◽  
Beidou Xi
Keyword(s):  
Tio2 Nanoparticles ◽  
Landfill Leachate ◽  
Control Method ◽  
Irradiation Time ◽  
Combined Treatment ◽  
Oxygen Demand ◽  
Infrared Spectrometry ◽  
Process Conditions ◽  
Optimal Process ◽  
Removal Rates

This study explored the performance of TiO2 nanoparticles in combination with aged waste reactors to treat landfill leachate. The optimum conditions for synthesis of TiO2 were determined by a series of characterizations and removal rates of methyl orange. The effect of the ultraviolet irradiation time, amount of the catalyst, and pH on the removal efficiency for the chemical oxygen demand (COD) and color in the leachate was explored to determine the optimal process conditions, which were 500 min, 4 g/L and 8.88, respectively. The removal rates for COD and chroma under three optimal conditions were obtained by the single factor control method: 89% and 70%; 95.56% and 70%; and 85% and 87.5%, respectively. Under optimal process conditions, the overall average removal rates for ammonium nitrogen (NH4+–N) and COD in the leachate for the combination of TiO2 nanoparticles and an aged waste reactor were 98.8% and 32.5%, respectively, and the nitrate (NO3−–N) and nitrite nitrogen (NO2–N) concentrations were maintained at 7–9 and 0.01–0.017 mg/L, respectively. TiO2 nanoparticles before and after the photocatalytic reaction were characterized by emission scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and Fourier transform infrared spectrometry. In addition, TiO2 nanoparticles have excellent recyclability, showing the potential of the photocatalytic/biological combined treatment of landfill leachate. This simulation of photocatalysis-landfilling could be a baseline study for the implementation of technology at the pilot scale.

Tobacco stalk-derived carbon prepared by one-step molten salt carbonization for supercapacitor

2021 ◽  
pp. 2151021
Author(s):  
Yuxuan Liu ◽  
Xinhua Cheng ◽  
Shenghui Zhang
Keyword(s):  
Aqueous Solution ◽  
Energy Density ◽  
Porous Structure ◽  
Molten Salt ◽  
Electrode System ◽  
Rate Performance ◽  
Heteroatom Doping ◽  
Hierarchically Porous Structure ◽  
One Step ◽  
Tobacco Stalk

High-performance capacitive carbon materials, derived from tobacco stalk, were prepared by a one-step carbonization process in molten carbonate. Owing to the high specific surface area (SSA) (1165.9 m2 g[Formula: see text] and heteroatom doping by the activation effect of molten salt medium for 3 h, the as-obtained carbon material with hierarchically porous structure exhibits an ideal capacitive property with delivering specific capacitances of 219.8, 188.0, 176.4, and 168.4 F g[Formula: see text] at 0.2, 0.5, 1, and 2 A g[Formula: see text], respectively, acceptable rate performance with 76.6% capacitance retention in range of 0.2–2 A g[Formula: see text], and good cyclic stability with 93% capacitance retention after 3000 charge–discharge cycles at 1 A g[Formula: see text], as well as energy density of 30.5 Wh kg[Formula: see text] at 0.2 A g[Formula: see text] and power density of 989.6 W kg[Formula: see text] at 2 A g[Formula: see text] in 1 mol L[Formula: see text] H2SO4 aqueous solution using a three-electrode system. Moreover, it delivers specific capacitances of 143.3, 140.2, 137.4, and 134.3 F g[Formula: see text] at 0.2, 0.5, 1, and 2 A g[Formula: see text], respectively, and excellent rate performance with 93.7% capacitance retention in range of 0.2–2 A g[Formula: see text], as well as energy density of 4.9 Wh kg[Formula: see text] at 0.2 A g[Formula: see text] and power density of 488.6 W kg[Formula: see text] at 2 A g[Formula: see text] in 6 mol L[Formula: see text] KOH aqueous solution using a symmetrical two-electrode system. The correlation between hierarchically porous structure with heteroatom doping and capacitive performance is also discussed.

scholarly journals Equilibrium modeling of mono and binary sorption of Cu(II) and Zn(II) onto chitosan gel beads

2016 ◽  
Vol 37 (4) ◽  
pp. 485-501 ◽  
Author(s):  
Józef Nastaj ◽  
Małgorzata Tuligłowicz ◽  
Konrad Witkiewicz
Keyword(s):  
Metal Ion ◽  
Ph Value ◽  
Experimental Studies ◽  
Process Conditions ◽  
Optimal Process ◽  
Sorption Data ◽  
Gel Beads ◽  
Two Component ◽  
Equilibrium Data ◽  
Chitosan Gel

Abstract The objective of the work are in-depth experimental studies of Cu(II) and Zn(II) ion removal on chitosan gel beads from both one- and two-component water solutions at the temperature of 303 K. The optimal process conditions such as: pH value, dose of sorbent and contact time were determined. Based on the optimal process conditions, equilibrium and kinetic studies were carried out. The maximum sorption capacities equaled: 191.25 mg/g and 142.88 mg/g for Cu(II) and Zn(II) ions respectively, when the sorbent dose was 10 g/L and the pH of a solution was 5.0 for both heavy metal ions. One-component sorption equilibrium data were successfully presented for six of the most useful three-parameter equilibrium models: Langmuir-Freundlich, Redlich-Peterson, Sips, Koble-Corrigan, Hill and Toth. Extended forms of Langmuir-Freundlich, Koble-Corrigan and Sips models were also well fitted to the two-component equilibrium data obtained for different ratios of concentrations of Cu(II) and Zn(II) ions (1:1, 1:2, 2:1). Experimental sorption data were described by two kinetic models of the pseudo-first and pseudo-second order. Furthermore, an attempt to explain the mechanisms of the divalent metal ion sorption process on chitosan gel beads was undertaken.

scholarly journals Study on Aqueous Enzymatic Extraction Process of Common Pistache Oil

2021 ◽  
Vol 251 ◽  
pp. 02058
Author(s):  
Feng Xuehua ◽  
Tao Ali ◽  
Song Zurong ◽  
Gong Panpan
Keyword(s):  
Ph Value ◽  
Orthogonal Experiment ◽  
Extraction Process ◽  
Optimal Time ◽  
Process Conditions ◽  
Optimal Process ◽  
Enzymatic Extraction ◽  
Hydrolysis Time ◽  
Aqueous Enzymatic Extraction ◽  
The Common

The aqueous enzymatic method was applied to extract the common pistache oil and the optimal extraction process conditions were identified. By observing the effect of enzymatic hydrolysis time, pH value, temperature on aqueous enzymatic extraction process and performing the orthogonal experiment based on the single factor test, the optimal process parameters were obtained, namely, the optimal time, temperature, and pH value were respectively 3 h, 50℃, and 7 with a final extraction rate of 25.38 %.

Surface Treatment of the Glass Fibers in Low Pressure Microvave Plasma

1983 ◽  
Vol 30 ◽  
Author(s):  
Ryszard Parosa
Keyword(s):  
Microwave Power ◽  
Industrial Application ◽  
Treatment Time ◽  
Plasma Reactor ◽  
Glass Fibers ◽  
Process Conditions ◽  
Plasma Region ◽  
Optimal Process ◽  
Driving System ◽  
Air Plasmas

ABSTRACTIn the method described here, oxygen and air plasmas were generated at pressure of 1 – 10 Torr in quartz tube placed inside various kinds of microwave cavieties. Cavieties were supplied by 10 to 500 W of microwave power / f=2.45 GHz /. Processed fiber was fastly moved across the plasma region by special driving system. Experimentally the optimal process conditions, i.e. treatment time and gas pressure, were found. Moreover, a special construction of a “long” plasma reactor for industrial application of the process was worked out.

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