Optimization of a Leaching Tank for Hydrometallurgical Recovery of Metals

2009 ◽  
Author(s):  
M. C. L. G. Vilarinho ◽  
N. M. B. Gonc¸alves ◽  
J. C. F. Teixeira
Keyword(s):  
Laboratory Tests ◽  
Metal Extraction ◽  
Cfd Model ◽  
High Concentration ◽  
Metal Plating ◽  
Metals Recovery ◽  
High Metal ◽  
Leaching Solution ◽  
Wide Compositional Range ◽  
Overall Efficiency

The sludge wastes generated by the metal plating industries are classified as hazardous wastes because of their high concentration of heavy metals. Amongst the various routes for their treatment, the hydrometallurgical processes are highly attractive because they can be tailored to the wide compositional range of such wastes and assure its metals recovery and/or toxicity reduction. In these processes the leaching operation is paramount to the overall efficiency. In this, the mixing of the leaching solution with sludge has to be effective in order to obtain high levels of metal extraction and make the process attractive. Most of the available data refers to laboratory tests. This paper reports on the use of CFD model to optimize the operation of a pilot size leaching tank. The results regarding the velocity field were compared with experimental data and proved that such techniques can be effectively applied to improve the process. A leaching experiment, with the best configuration for the mixing, yielded a high metal extraction, suggesting that this technique can be successfully implemented for the treatment of such wastes.

scholarly journals Service Life Prediction of Shaft Sidewall Exposed to Sulfate Environment

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Wei He ◽  
Xia Meng ◽  
Ji-hui Zhao
Keyword(s):  
Life Prediction ◽  
Laboratory Tests ◽  
Residual Life ◽  
Underground Water ◽  
Corrosion Mechanism ◽  
Research Subject ◽  
High Concentration ◽  
Degradation Model ◽  
Immersion Corrosion ◽  
Different Parts

Under the influence of underground water with high concentration of sulfate, several vertical shafts in the Huang-Huai region are seriously corroded but have varying degradation degrees in different parts. Taking the auxiliary shaft of Lin-Huan coal mine as the research subject, the mechanism of this phenomenon was studied. Then, wet-dry alternated and immersion corrosion tests were carried out, and it was found that only the dry-wet alternated accelerate test is representative of the corrosion mechanism that cause the corrosion in the shaft. However, it will cost much time and money for the laboratory test to reach the same degradation depth. To solve this problem, combining with field and laboratory tests, a modified theoretical degradation model was developed to evaluate the residual life of the corroded sidewall. The results indicate that the residual life of the shaft sidewall is 25 years, and the damaged parts have no need for an immediate reinforcement.

scholarly journals Influence of Parapets on Wave Overtopping on Mound Breakwaters with Crown Walls

2019 ◽  
Vol 11 (24) ◽  
pp. 7109 ◽  
Author(s):  
Jorge Molines ◽  
Arnau Bayon ◽  
M. Esther Gómez-Martín ◽  
Josep R. Medina
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Laboratory Tests ◽  
Cfd Model ◽  
Wave Overtopping ◽  
Numerical Tests ◽  
Computational Fluid Dynamics Cfd ◽  
The Mean

Background literature on the influence of parapets on the overtopping of mound breakwaters is limited. In this study, numerical tests were conducted using computational fluid dynamics (CFD) to analyze the influence of nine crown wall geometries (seven with parapets). The CFD model was implemented in OpenFOAM® and successfully validated with laboratory tests. A new estimator of the dimensionless mean wave-overtopping discharges (logQ) on structures with parapets is proposed. The new estimator depends on the estimation of logQ of the same structure without a parapet. The effects on wave overtopping of the parapet angle (εp), parapet width (wp), and parapet height (hp) were analyzed. Low values of εp and wp/hp ≈ 1 produced the highest parapet effectiveness to reduce the mean wave-overtopping discharges.

scholarly journals Photocatalytic decomposition of gaseous formaldehyde usingTiO2,SiO2−TiO2and Pt−TiO2

2003 ◽  
Vol 5 (1) ◽  
pp. 21-25 ◽  
Author(s):  
Byung-Yong Lee ◽  
Sung-Wook Kim ◽  
Sung-Chul Lee ◽  
Hyun-Ho Lee ◽  
Suk-Jin Choung
Keyword(s):  
Photocatalytic Decomposition ◽  
Commercial Application ◽  
Reverse Effect ◽  
High Concentration ◽  
Visible Spectra ◽  
Photocatalytic Activities ◽  
High Metal ◽  
Uv Visible ◽  
Gaseous Formaldehyde ◽  
Better Than

In this study, in order to improve the photocatalytic decomposition activities of formaldehyde,TiO2catalyst modified withSiO2substitution and metal (Pt, Cu and Fe) impregnation, were tested. In case ofTiO2substituted bySiO2, the optimal catalytic activity was found at the mole ration of 2 : 8. Among the metal impregnatedTiO2, the Pt impregnatedTiO2showed the best activity even better than that of P-25 which is widely used in commercial application. However, Cu and Fe impregnatedTiO2showed the reverse effect. In the case ofSiO2substitutedTiO2the observed values of photoluminescence spectroscopy were quite proportional to the photocatalytic activities depending upon the mole ratio ofSiO2toTiO2. However, for the samples of metal impregnatedTiO2, the reverse relationships were found. In UV-visible spectra for metal impregatedTiO2, the transmittance value was reduced depending upon the loading of metals. The enhanced photocatalytic activity for high metal loading onTiO2might be associated with the high concentration of excited electron that was monitored through UV-visible spectra.

scholarly journals Extraction Of Cobalt From Spent CMB Catalyst Using Supercritical CO2

2015 ◽  
Vol 60 (2) ◽  
pp. 1535-1537 ◽  
Author(s):  
S.-H. Joo ◽  
S.M. Shin
Keyword(s):  
Ternary System ◽  
Metal Ions ◽  
Supercritical Co2 ◽  
Extraction Process ◽  
Metal Extraction ◽  
Organic System ◽  
Leaching Solution ◽  
Complexation Process

Abstract The metal extraction from spent CMB catalyst using supercritical CO2(scCO2) was investigated with single organic system, binary organic system and ternary organic system to extract metal ions. Leaching solution of spent CMB catalyst containing 389 mg L−1 Co2+, 187 mg L−1 Mn2+, 133 mg L−1 Na+, 14.97 mg L−1 Ca2+ and 13.2 mg L−1 Mg2+. The method consists of scCO2/ligands complexation process and metal extraction process at 60°C and 200bar. The result showed the Co and Mn was selectively extracted from Mg, Ca and Na in the ternary system of mixture of Cyanex272, DEA and Alamine304-I.

scholarly journals Study on the Extraction and Separation of Zinc, Cobalt, and Nickel Using Ionquest 801, Cyanex 272, and Their Mixtures

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 401
Author(s):  
Wensen Liu ◽  
Jian Zhang ◽  
Zhenya Xu ◽  
Jie Liang ◽  
Zhaowu Zhu
Keyword(s):  
Phosphinic Acid ◽  
Metal Extraction ◽  
Nickel Extraction ◽  
Extraction And Separation ◽  
Cyanex 272 ◽  
High Metal ◽  
Separation Factors ◽  
Job's Method ◽  
Better Than ◽  
Cobalt And Nickel

Both Cyanex 272 (bis (2,4,4-trimethylpentyl) phosphinic acid) and Ionquest 801 (2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester) are commonly used for metal extraction and separation, particularly for zinc, cobalt, and nickel, which are often found together in processing solutions. Detailed metal extractions of zinc, cobalt, and nickel were studied in this paper using Cya-nex 272, Ionquest 801, and their mixtures. It was found that they performed very similarly in zinc selectivity over cobalt. Cyanex 272 performed much better than Ionquest 801 in cobalt separation from nickel. However, very good separation of them was also obtained with Ionquest 801 at its low concentration with separation factors over 4000, indicating high metal loading of cobalt can significantly suppress nickel extraction. Slop analysis proved that two moles of dimeric extractants were needed for one mole extraction of zinc and cobalt, but three moles were needed for the extraction of one mole nickel. A synergistic effect was found between Cyanex 272 and Ionquest 801 for three metal extractions with the synergistic species of M(AB) determined by the Job’s method.

Bioreactor Process Optimization for Bioleaching of Fine-Grained Residues from Copper Smelting

2015 ◽  
Vol 1130 ◽  
pp. 321-324 ◽  
Author(s):  
Cindy Klink ◽  
Juliane Heim ◽  
Birgit Daus ◽  
Sebastian Eisen ◽  
Michael Schlömann ◽  
...  
Keyword(s):  
Metal Extraction ◽  
Copper Smelting ◽  
Small Scale ◽  
Toxic Heavy Metals ◽  
Fine Grained ◽  
Acidophilic Bacteria ◽  
Leaching Solution ◽  
Leaching Residue ◽  
Xrf Analyses ◽  
Bioreactor Process

Theisen sludge, a fine-grained by-product from copper smelting is a secondary resource for the winning of strategic elements by metal-oxidizing acidophilic bacteria. Screening for cultures, that grew in presence of the toxic heavy metals containing fly ash was successfully performed. Small scale experiments in shaking flasks with subsequent analysis of the pregnant leaching solution (PLS) revealed biological extraction of the major (zinc and copper) and minor metals (cobalt and rhenium). Results were confirmed by XRF analyses of the leaching residue. The bioleaching approach was up-scaled in stirred tank bioreactors under controlled conditions. Optimization of metal-extraction rates will be achieved by regulation of process-parameters, predominantly the redox-potential.

Metal Recovery and Exploitation of Lignite Ashes by Combined Physicochemical and Biotechnological Approaches

2015 ◽  
Vol 1130 ◽  
pp. 296-299
Author(s):  
René Kermer ◽  
Sabrina Hedrich ◽  
Beate Brett ◽  
Daniel Schrader ◽  
Konstantin Räuchle ◽  
...  
Keyword(s):  
Phase Changes ◽  
Raw Material ◽  
Metal Extraction ◽  
Direct Reaction ◽  
Chemical Leaching ◽  
Potential Source ◽  
High Metal ◽  
Pre Treatment ◽  
Potential Exploitation ◽  
Specific Metal

Ashes from lignite combustion for power generation contain strategic metals, metalloids and rare earth elements and may thus be a potential source of industrially demanded metals. The presented project focuses on the assessment and exploitation of this potential raw material. Lignite ash assessment showed that largest ash amounts for potential exploitation are available in the Lusatia district, Saxony. Mechanical ash pre-treatment in principle provided enriched fractions by different methods but still suffered from low yields of enriched fractions. Thermal ash processing showed multiple significant phase changes compared to original ash. Subsequent chemical leaching using HClaq resulted in high metal extraction. Alternatively, bioleaching was applied using acidophilic Fe (II) and S-oxidizing or Fe (III)-reducing microorganisms (MO) as well as heterotrophic MO. The results indicated likewise high and partly specific metal mobilizations. Industrial ash exploitation was accomplished by direct reaction with acids resulting in Al-Fe-solutions which potentially can be applied in water treatment.

Biomass Production and Inoculation of Industrial Bioleaching Processes

2013 ◽  
Vol 825 ◽  
pp. 296-300 ◽  
Author(s):  
Pilar Parada ◽  
Pedro Morales ◽  
Roberto Collao ◽  
Roberto A. Bobadilla-Fazzini ◽  
Ricardo Badilla
Keyword(s):  
Microbial Activity ◽  
Residence Time ◽  
High Concentration ◽  
Industrial Operations ◽  
Continuous Regime ◽  
Nominal Capacity ◽  
Early Expression ◽  
Leaching Solution ◽  
Sulfur Oxidizing ◽  
Time Required

Microbial activity inleaching processes accounts for 4% of today’s copper produced in the world. Factorsrelated with lesser overall metal recoveries, no recovery of precious metalsand molybdenum in comparison with conventional concentration/smelting &refining technologies and the high prices of metals inhibit the use of bioleachingat a larger scale. In order to increase bioleaching rates and overall metal recoveries,continuous inoculation of the ore with a leaching solution containing specific adaptedconsortium of microorganisms, allows an early expression of microbial activity,reducing 2-3 fold the time required by ore native bearing microflora to grow.This leaching solution concentrated in microorganisms can be produced by meansof bioreactors operated in continuous regime. Unfortunately biomining microorganisms have a very low duplication timewhen comparing to common microbes like E.colior B. subtilis, that forces the useof huge volume bioreactors in the case of conventional bioreactors, to ensurethe growth of microorganisms have sufficient residence time. To overcome thisproblem, we have designed a very efficient air-lift bioreactor (Patent Registration No. CL 48319), that can be used at industrial operations for the production ofsolutions with a high concentration of biomining microorganisms, for theinoculation of bioleaching heaps, with lesser residence time in comparison toconventional bioreactors. Ourbioreactor has an internal recirculation for producing sulfide-ore bioleachingsolutions, with a phase-separating and solids-recirculation system, without theneed to impel the suspension containing the solids towards the bioreactor withpumps, using diatomaceous earth, ferric precipitates and/or elemental sulfur asa solid support to immobilize iron and/or sulfur-oxidizing microorganisms. Dependingon the source of energy supplied for the growth of the microorganisms, thebioreactor can produce either a solution concentrated in ferric ions andiron-oxidizing bacteria or sulfur oxidizing bacteria. In order to validate ourbioreactor design at industrial scale, a trial was carried out in an air-liftbioreactor of 35 m3 nominal capacity, which is part of a biomassplant located in Radomiro Tomic Division of CODELCO. In this article, theresults of the test proving the advantages and satisfactory design of ourbioreactor for producing continuously iron-oxidizing bacteria and sulfuroxidizing bacteria for inoculation and irrigation of heaps and dumps are shown.

Evolution Of Defects Induced By High Energy He Implantation In Gold-Diffused Silicon

2001 ◽  
Vol 669 ◽  
Author(s):  
R. El Bouayadi ◽  
G. Regula ◽  
B. Pichaud ◽  
M. Lancin ◽  
J. J. Simon ◽  
...  
Keyword(s):  
Deep Level ◽  
Critical Diameter ◽  
High Energy ◽  
High Concentration ◽  
High Metal ◽  
Different Temperatures ◽  
Section Electron ◽  
Transient Spectroscopy ◽  
Secondary Ion ◽  
Minority Carriers

ABSTRACTSilicon samples were gold-diffused at different temperatures, implanted with He ions at 1.6 MeVand then annealed at 1050°C for 2 hours. The implantation induced-defect structure and their distributionin the depth of the sample, studied by conventional and high resolution cross section electron microscopy (HRXTEM) depend on the gold level introduced in the wafer prior to the gettering process. A high concentration of gold in silicon seems to influence the defect configuration in the cavity zone. Indeed, gold chemisorbed atcavities can homogenize the surface energy of their planes in different orientations, and can increase the cavity critical diameter beyond they become facetted. Secondary ion mass spectroscopy (SIMS) profiles exhibit ashouldered shape and a width closely related to the presence of the defects (observed by XTEM) which are veryefficient sinks both for gold and copper atoms. Unfortunately, the electrical improvement of the material (checked by minority carriers diffusion length measurements MCDL) is not achieved by this gettering process, probably due to the high metal impurity concentrations remaining out of the gettering zone, to the presence of AuCu complexes and η-Cu3Si precipitates identified by deep level transient spectroscopy (DLTS)measurements and HRXTEM observations respectively.

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