scholarly journals The sequential adsorption of gold, copper, silver, and palladium from pyrolysis solid product leach solution of waste PCBs

2021 ◽  
Author(s):  
Ece Yapıcı ◽  
Aysun Özkan ◽  
Zerrin Günkaya ◽  
Müfide Banar
Keyword(s):  
Leach Solution ◽  
Solid Product ◽  
Waste Pcbs ◽  
Sequential Adsorption

scholarly journals Copper solvent extraction from chalcopyrite concentrate acid leach solutions by LIX 984

2006 ◽  
Vol 42 (1) ◽  
pp. 1-11
Author(s):  
K. Elamari ◽  
E.A. Jdid ◽  
P. Blazy
Keyword(s):  
Solvent Extraction ◽  
Sulphuric Acid Solution ◽  
Leach Solution ◽  
Copper Production ◽  
Copper Extraction ◽  
Solid Product ◽  
Acid Leach ◽  
Concentrate Acid ◽  
Hydrometallurgical Treatment ◽  
Chalcopyrite Concentrate

Copper production from ores or sulphide concentrates is classically realized by pyrometallurgical route. In this study, hydrometallurgical treatment of a copper sulphide concentrate, provided by Hajar Mine (ONA-Group, Morocco), was tested by using a mixture of nitric and hexafluorosilicic acids. Copper is present in the solid product as chalcopyrite and its amount is 28.1 % by weight. Leaching stage allows to dissolve more than 90% of copper witch is accompanied, in the same averages, by Zn and Fe. The leach solution obtained has pH = 0.6 and Eh = 580 mV/ENH and contains 19.3 g/L Cu, 18.1 g/L Fe, 4.5 g/L Zn and 0.03 g/L Pb. The recovery of copper from this leach solution was curried out by solvent extraction using Lix 984, diluted in Escaid 110. McCabe - Thiele distribution isotherms showed that at pH 1.7 total and selective copper extraction can be realized with ?o:?a =1.5:1 in 3 extraction stages. Stripping of the loaded copper by treating the organic phases was easily obtained by a sulphuric acid solution.

Improving soil remediation through characterization

1995 ◽  
Vol 53 ◽  
pp. 386-387
Author(s):  
E. C. Buck ◽  
N. L. Dietz ◽  
J. K. Bates
Keyword(s):  
Dust Particles ◽  
Radiochemical Analysis ◽  
Solid Product ◽  
Uranium Contamination ◽  
Physical Separation ◽  
X Ray ◽  
Rocky Flats ◽  
Remediation Strategies ◽  
Bearing Materials ◽  
X Ray Absorption

Operations at former weapons processing facilities in the U. S. have resulted in a large volume of radionuclidecontaminated soils and residues. In an effort to improve remediation strategies and meet environmental regulations, radionuclide-bearing particles in contaminant soils from Fernald in Ohio and the Rocky Flats Plant (RFP) in Colorado have been characterized by electron microscopy. The object of these studies was to determine the form of the contaminant radionuclide, so that it properties could be established [1]. Physical separation and radiochemical analysis determined that uranium contamination at Fernald was not present exclusively in any one size/density fraction [2]. The uranium-contamination resulted from aqueous and solid product spills, air-borne dust particles, and from the operation of an incinerator on site. At RFP the contamination was from the incineration of Pu-bearing materials. Further analysis by x-ray absorption spectroscopy indicated that the majority of the uranium was in the 6+ oxidation state [3].

Rapid Isolation of High Molecular Weight Urokinase from Native Human Urine

1982 ◽  
Vol 47 (03) ◽  
pp. 197-202 ◽  
Author(s):  
Kurt Huber ◽  
Johannes Kirchheimer ◽  
Bernd R Binder
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Human Urine ◽  
Gel Filtration ◽  
Chain Structure ◽  
The Other ◽  
Single Chain ◽  
Apparent Homogeneity ◽  
Sequential Adsorption

SummaryUrokinase (UK) could be purified to apparent homogeneity starting from crude urine by sequential adsorption and elution of the enzyme to gelatine-Sepharose and agmatine-Sepharose followed by gel filtration on Sephadex G-150. The purified product exhibited characteristics of the high molecular weight urokinase (HMW-UK) but did contain two distinct entities, one of which exhibited a two chain structure as reported for the HMW-UK while the other one exhibited an apparent single chain structure. The purification described is rapid and simple and results in an enzyme with probably no major alterations. Yields are high enough to obtain purified enzymes for characterization of UK from individual donors.

scholarly journals Evaluation of Joint Management of Pine Wood Waste and Residual Microalgae for Agricultural Application

2020 ◽  
Vol 13 (1) ◽  
pp. 53
Author(s):  
José Guillermo Rosas ◽  
Natalia Gómez ◽  
Jorge Cara-Jiménez ◽  
Judith González-Arias ◽  
Miguel Ángel Olego ◽  
...  
Keyword(s):  
Solid Fraction ◽  
Soil Amendment ◽  
Carbon Sink ◽  
Wood Waste ◽  
Solid Product ◽  
Pine Wood ◽  
Joint Management ◽  
Agricultural Application ◽  
Negative Balance ◽  
By Products

This work addresses the joint management of residual microalgae and pine wood waste through pyrolysis to obtain a solid product for its use as soil amendment and two other by-products (liquid and gaseous) that can be used for energy purposes. Two management routes have been followed. The first route is through the co-pyrolysis of mixtures of both residual materials in several proportions and the later use of their solid fraction for soil amendment. The second route is the pyrolysis of pine wood waste and its direct combination with dried residual microalgae, also using it as soil amendment. The solid fraction assessment shows that from seven solid products (biochar) three stand out for their positive applicability in agriculture as soil amendment. In addition, they also present the benefit of serving as carbon sink, giving a negative balance of CO2 emissions. However, caution is suggested due to biochar applicability being subject to soil characteristics. To ensure the sustainability of the overall process, the energy available in liquid and gaseous fractions has been assessed for covering the drying needs of the residual microalgae in both cases. These results suggest that the pyrolysis process is a sustainable way to manage specific evaluated residues and their products.

scholarly journals Preliminary Study on Gold Recovery from High Grade E-Waste by Thiourea Leaching and Electrowinning

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 235
Author(s):  
Nicolò Maria Ippolito ◽  
Ionela Birloaga ◽  
Francesco Ferella ◽  
Marcello Centofanti ◽  
Francesco Vegliò
Keyword(s):  
Sulfuric Acid ◽  
Leach Solution ◽  
High Grade ◽  
Gold Dissolution ◽  
Plastic Part ◽  
The Third ◽  
Current Consumption ◽  
Different Types ◽  
Preliminary Study ◽  
A Current

The present paper is focused on the extraction of gold from high-grade e-waste, i.e., spent electronic connectors and plates, by leaching and electrowinning. These connectors are usually made up of an alloy covered by a layer of gold; sometimes, in some of them, a plastic part is also present. The applied leaching system consisted of an acid solution of diluted sulfuric acid (0.2 mol/L) with thiourea (20 g/L) as a reagent and ferric sulfate (21.8 g/L) as an oxidant. This system was applied on three different high-grade e-waste, namely: (1) Connectors with the partial gold-plated surface (Au concentration—1139 mg/kg); (2) different types of connectors with some of which with completely gold-plated surface (Au concentration—590 mg/kg); and (3) connectors and plates with the completely gold-plated surface (Au concentration—7900 mg/kg). Gold dissolution yields of 52, 94, and 49% were achieved from the first, second, and third samples, respectively. About 95% of Au recovery was achieved after 1.5 h of electrowinning at a current efficiency of only 4.06% and current consumption of 3.02 kWh/kg of Au from the leach solution of the third sample.

scholarly journals Study on Ultrasonically-Enhanced Sulfuric Acid Leaching of Nickel from Nickel-Containing Residue

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 810
Author(s):  
Zhanyong Guo ◽  
Ping Guo ◽  
Guang Su ◽  
Fachuang Li
Keyword(s):  
Sulfuric Acid ◽  
Acid Leaching ◽  
Ultrasonic Waves ◽  
Sulfuric Acid Leaching ◽  
Solid Product ◽  
Leaching Process ◽  
Diffusion Controlled ◽  
Extraction Degree ◽  
Ultrasonic Conditions ◽  
Complex Nickel

In this paper, nickel-containing residue, a typical solid waste produced in the battery production process, was used to study the cavitation characteristics of ultrasonic waves in a liquid–solid reaction. The ultrasonically-enhanced leaching technology for multicomponent and complex nickel-containing residue was studied through systematic ultrasonic-conventional comparative experiments. An ultrasonic leaching kinetics model was established which provided reliable technological guidance and basic theory for the comprehensive utilization of nickel-containing residue. In the study, it was found that ultrasonically-enhanced leaching for 40 min obtained the same result as conventional leaching for 80 min, and the Ni extraction degree reached more than 95%. According to the kinetic fitting of the leaching process, it was found that the sulfuric acid leaching process belonged to the diffusion-controlled model of solid product layers under conventional and ultrasonic conditions, and the activation energy of the reaction was Ea1 = 17.74 kJ/mol and Ea2 = 5.04 kJ/mol, respectively.

scholarly journals Thermodynamic and Experimental Investigation of Solar-Driven Biomass Pyro-Gasification Using H2O, CO2, or ZnO Oxidants for Clean Syngas and Metallurgical Zn Production

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 687
Author(s):  
Srirat Chuayboon ◽  
Stéphane Abanades
Keyword(s):  
Beech Wood ◽  
Biomass Gasification ◽  
Biomass Energy ◽  
Solid Product ◽  
Product Characterization ◽  
Single Process ◽  
U Value ◽  
Chemical Products ◽  
Particle Shapes ◽  
Promising Avenue

The solar gasification of biomass represents a promising avenue in which both renewable solar and biomass energy can be utilized in a single process to produce synthesis gas. The type of oxidant plays a key role in solar-driven biomass gasification performance. In this study, solar gasification of beech wood biomass with different oxidants was thermodynamically and experimentally investigated in a 1.5 kWth continuously-fed consuming bed solar reactor at 1200 °C under atmospheric pressure. Gaseous (H2O and CO2) as well as solid (ZnO) oxidants in pellet and particle shapes were utilized for gasifying beech wood, and the results were compared with pyrolysis (no oxidant). As a result, thermodynamic predictions provided insights into chemical gasification reactions against oxidants, which can support experimental results. Compared to pyrolysis, using oxidants significantly promoted syngas yield and energy upgrade factor. The highest total syngas yield (63.8 mmol/gbiomass) was obtained from biomass gasification with H2O, followed by CO2, ZnO/biomass mixture (pellets and particles), and pyrolysis. An energy upgrade factor (U) exceeding one was achieved whatever the oxidants, with the maximum U value of 1.09 from biomass gasification with ZnO, thus highlighting successful solar energy storage into chemical products. ZnO/biomass pellets exhibited greater gas yield, particularly CO, thanks to enhanced solid–solid reaction. Solid product characterization revealed that ZnO can be reduced to high-purity Zn through solar gasification, indicating that solar-driven biomass gasification with ZnO is a promising innovative process for CO2-free sustainable co-production of metallic Zn and high-quality syngas.

scholarly journals Electrochemical and Spectroelectrochemical Studies on the Reactivity of Perimidine–Carbazole–Thiophene Monomers towards the Formation of Multidimensional Macromolecules versus Stable π-Dimeric States

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2167
Author(s):  
Malgorzata Czichy ◽  
Patryk Janasik ◽  
Pawel Wagner ◽  
David L. Officer ◽  
Mieczyslaw Lapkowski
Keyword(s):  
Conjugated Polymer ◽  
Density Functional ◽  
Radical Cations ◽  
Covalent Bonding ◽  
Oxidation States ◽  
Solid Product ◽  
Functional Theory ◽  
Subsequent Oxidation ◽  
Molecular Ordering ◽  
Significant Difference

During research on cross-linked conducting polymers, double-functionalized monomers were synthesized. Two subunits potentially able to undergo oxidative coupling were used—perimidine and, respectively, carbazole, 3,6-di(hexylthiophene)carbazole or 3,6-di(decyloxythiophene)carbazole; alkyl and alkoxy chains as groups supporting molecular ordering and 14H-benzo[4,5]isoquinone[2,1-a]perimidin-14-one segment promoting CH⋯O interactions and π–π stacking. Electrochemical, spectroelectrochemical, and density functional theory (DFT) studies have shown that potential-controlled oxidation enables polarization of a specific monomer subunit, thus allowing for simultaneous coupling via perimidine and/or carbazole, but mainly leading to dimer formation. The reason for this was the considerable stability of the dicationic and tetracationic π-dimers over covalent bonding. In the case of perimidine-3,6-di(hexylthiophene)carbazole, the polymer was not obtained due to the steric hindrance of the alkyl substituents preventing the coupling of the monomer radical cations. The only linear π-conjugated polymer was obtained through di(decyloxythiophene)carbazole segment from perimidine-di(decyloxythiophene)-carbazole precursor. Due to the significant difference in potentials between subsequent oxidation states of monomer, it was impossible to polarize the entire molecule, so that both directions of coupling could be equally favored. Subsequent oxidation of this polymer to polarize the side perimidine groups did not allow further crosslinking, because rather the π–π interactions between these perimidine segments dominate in the solid product.

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