scholarly journals Characterization of precipitate formed during the removal of iron and precious metals from sulphate leach solutions

2017 ◽  
Vol 117 (8) ◽  
pp. 771-778
Author(s):  
R. Coetzee
Keyword(s):  
Precious Metals

scholarly journals MINERALOGICAL AND GEOCHEMICAL CHARACTERIZATION OF THE OLYMPIAS MINE TAILINGS, NE CHALKIDIKI, GREECE

2017 ◽  
Vol 50 (4) ◽  
pp. 2088
Author(s):  
S. Zaimis ◽  
M. Vavelidis ◽  
D. Alifragkis ◽  
V. Melfos ◽  
N. Kantiranis ◽  
...  
Keyword(s):  
Precious Metals ◽  
Thin Layers ◽  
Mine Wastes ◽  
X Ray Diffraction ◽  
Ph Measurements ◽  
Rock Composition ◽  
Geochemical Characterization ◽  
Fe Oxyhydroxides ◽  
Mn Oxides

The Olympias tailings of NE Chalkidiki, Greece represent the mine wastes produced by the beneficiation of the Pb-Zn-Au-Ag ore deposit, which is hosted within the carbonate rocks of the Kerdylia Unit. In the present study X-Ray diffraction (XRD), scanning electron microscopy (SEM), optical microscopy, chemical analyses and pH measurements were conducted to determine the tailings mineralogy and chemical composition. The results indicated that they consist of gangue (quartz, rhodochrosite, calcite, dolomite, feldspars, micas, kaolinite and actinolite) and sulfide minerals (pyrite, arsenopyrite, sphalerite, chalcopyrite and galena), reflecting the source ore and its host rock composition, accompanied by traces of Fe-oxides (magnetite, hematite), Fe oxyhydroxides (goethite) and Mn-oxides, often enriched in Zn and Pb and in some cases Fe, Sb and As. Secondary sulfates (gypsum, jarosite) and surface efflorescent salts (ferrohexahydrite, hexahydrite, halotrichite) have also been recognized. The Olympias tailings are generally unoxidized, generating an alkaline environment. However, variations in composition result in the formation of restricted separate phases, such as thin layers and lenses of oxidized material that generates an acidic environment. In terms of precious metals content, the Olympias tailings are enriched in Au (up to 12 g/t) and Ag (up to 20 g/t).

scholarly journals A influência de Shakespeare em Grande sertão: veredas – as Três Mulheres e os Três Metais / Shakespeare’s Influence in Grande sertão: veredas – The Three Women and the Three Metals

2021 ◽  
Vol 30 (2) ◽  
pp. 100
Author(s):  
Daniel Cavalcanti Atroch
Keyword(s):  
William Shakespeare ◽  
Precious Metals ◽  
King Lear ◽  
The Novel ◽  
Female Characters ◽  
Gold Silver ◽  
True Love ◽  
Joao Guimaraes Rosa ◽  
The Right

Resumo: Este artigo aborda como é atualizado, no Grande sertão: veredas, um motivo fundamental para a tragédia Rei Lear: a escolha amorosa envolvendo três mulheres relacionadas ao ouro, à prata e ao chumbo. A simbologia subjacente aos metais é determinante para a caracterização das personagens femininas tanto do romance quanto da tragédia, analisadas, aqui, em perspectiva comparativa. Em Rei Lear, os metais preciosos, o ouro e a prata, estão associados a Goneril e Reagan, as filhas más que herdam o reino, enquanto Cordélia, a filha bondosa e preferida do rei, é representada pelo chumbo e acaba deserdada. Em Grande sertão: veredas, o ouro e a prata figuram na caracterização de Nhorinhá, a prostituta por quem Riobaldo se apaixona, e Otacília, sua esposa, enquanto Diadorim, o verdadeiro amor, está relacionado ao chumbo e permanece sublimado. Assim, os metais preciosos simbolizam, em ambas as obras, o equívoco amoroso, enquanto o chumbo guarda a mulher certa – Cordélia na tragédia, e Diadorim no romance. Diadorim e Cordélia possuem, ainda, outras analogias: ambas são filhas de grandes líderes, dedicam fidelidade irrestrita ao pai, possuem ligação com o arquétipo da donzela-guerreira e suas mortes representam momentos de anagnórisis para Riobaldo e Lear.Palavras-chave: literatura comparada; Grande sertão: veredas; João Guimarães Rosa; Rei Lear; William Shakespeare.Abstract: This article discusses how it is updated, in Grande sertão: veredas, a fundamental theme for the tragedy King Lear: the love choice involving three women related to gold, silver and lead. The symbology related to the metals is decisive for the characterization of the female characters of both the novel and the tragedy, analyzed here, in a comparative perspective. In King Lear, the precious metals, gold and silver, are associated with Goneril and Reagan, the evil daughters who inherit the kingdom, while Cordelia, Lear’s kind and preferred daughter, is represented by lead and ends up disinherited. In Grande sertão: veredas, gold and silver emerge in the characterization of Nhorinhá, the prostitute with whom Riobaldo falls in love, and Otacília, his wife, while Diadorim, the true love, is related to lead, and remains sublimated. Thus, the precious metals, in both works, symbolize the loving mistake, while the lead keeps the right woman – Cordelia, in the tragedy, and Diadorim in the novel. Diadorim and Cordélia also have other analogies: both are daughters of great leaders, dedicate unrestricted fidelity to their father, have a connection with the warrior-maiden archetype, and their deaths represent moments of anagnorisis for Riobaldo and Lear.Keywords: comparative literature; Grande sertão: veredas; João Guimarães Rosa; King Lear; William Shakespeare.

Printed Circuit Boards Recycling: Characterization of Granulometric Fractions from Shredding Process

2010 ◽  
Vol 636-637 ◽  
pp. 1434-1439 ◽  
Author(s):  
Paula C. Oliveira ◽  
Marta Cabral ◽  
Carlos A. Nogueira ◽  
Fernanda Margarido
Keyword(s):  
Printed Circuit Boards ◽  
Precious Metals ◽  
Chemical Characterization ◽  
Average Diameter ◽  
Ceramic Materials ◽  
Size Reduction ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Minor Elements

In electronic appliances, printed circuit boards (PCB) represent an important component, containing high grade of valuable metals, besides organic resins and some ceramic materials. Copper is the major metal in PBC’s composition (normally higher than 20% w/w) but many other secondary and minor metal elements, including precious metals, are found in PCB’s. Recycling of PCB´s involves firstly the shredding operation, which is crucial in order to liberate particles from different materials, allowing its further processing by other mechanical, physical and chemical technologies. An efficient shredding operation is difficult to achieve due to the high heterogeneity of these wastes involving materials with different mechanical properties and complex assemblies. This paper presents results from laboratorial studies of shredding of PCB’s and the evaluation of size reduction efficiency as well as the chemical characterization of the obtained shredded fractions. Results showed that an efficient size reduction (characteristic average diameter d50=1.0mm) is obtained using two shredding stages of PCB’s, the first one with a grab shredder and the second one with a cutting mill. Chemical analysis of shredded PCB’s indicated that copper is the principal metal present (28%) followed by Sn, Zn, Pb and Al (3-5%) and many other minor elements. The fine fractions were rich in plastic materials while the metals were essentially present in the intermediate fractions (0.3-1.5 mm). These results can lead to guidelines regarding further design of the physical separation steps in the recycling processes.

Characterization of PCBs from Obsolete Computers Aiming the Recovery of Precious Metals

2018 ◽  
pp. 147-154
Author(s):  
Mariana Alves de Carvalho ◽  
Marcos Paulo Kohler Caldas ◽  
Jorge Alberto Soares Tenório ◽  
Denise Crocce Romano Espinosa
Keyword(s):  
Precious Metals

Chemical Characterization of a Mineral Deposit of Economic Interest

2015 ◽  
Vol 1766 ◽  
pp. 115-122
Author(s):  
E. Cerecedo ◽  
V. Rodríguez ◽  
P.D. Andrade ◽  
E. Salinas ◽  
J. Hernández ◽  
...  
Keyword(s):  
Precious Metals ◽  
Chemical Characterization ◽  
Mineral Deposit ◽  
Black Shales ◽  
Economic Interest ◽  
Base Metals ◽  
Rock Unit ◽  
Ore Deposit ◽  
Representative Samples

ABSTRACTChemical and structural characterization of four representative samples of an ore deposit located in the eastern of Hidalgo State was carried out. According with the results, it could be appreciate some areas showing silicified zones with abundant amounts of disseminated pyrites that are part of a rock unit from early Jurassic consisting in inter - bedded black shales and sandstones. Thus, the contents of base metal were greater than 30 ppm Zn and 9 ppm Cu. Chemical analysis of rock gave the following results; 82 ppm of Ba, 1.64 % Wt. Fe, 0.08 % Wt. Ti, 40.8 % Wt. Si, 20 ppm of Ce, 2.2 ppm Co, 30 ppm Cr, 2.7 ppm Cs, 0.9 ppm Er, 2.5 ppm Ga, 1.6 ppm Gd , 1.5 ppm Ge, 9 ppm La, 71 ppm Li, 104 ppm Mn, 10 ppm Nd , 17 ppm Rb, 2 ppm Se, 9 ppm Sr, 10 ppm Ta, 6 ppm Te, 28 ppm V, 9 ppm Y, and 0.7 ppm Yb, among others. Finally, the values found for precious metals, were; Au < 0.02 ppm, Pd <0.05 ppm, Pt <0.05 ppm. It was inferred that the low content of base metals in outcrop studied, are due to the alteration of the black shales. According to these results, we can consider a stratiform – type mineralization of Pb-Zn which could be prospective for SEDEX – Type deposit. By means of XRD, it was possible to identify; pyrite, chalcopyrite, pyrrhotite, and minor amounts of sphalerite and Co -Ni arsenide.

scholarly journals Environmental and Socioeconomic Impact of Copper Slag—A Review

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1504
Author(s):  
Tlotlo Solomon Gabasiane ◽  
Gwiranai Danha ◽  
Tirivaviri A. Mamvura ◽  
Tebogo Mashifana ◽  
Godfrey Dzinomwa
Keyword(s):  
Direct Reduction ◽  
Precious Metals ◽  
Copper Slag ◽  
Secondary Source ◽  
Socioeconomic Impacts ◽  
Physical Separation ◽  
Valuable Metals ◽  
Nickel Ores ◽  
Land Space

Copper slag is generated when copper and nickel ores are recovered from their parent ores using a pyrometallurgical process, and these ores usually contain other elements which include iron, cobalt, silica, and alumina. Slag is a major problem in the metallurgical industries as it is dumped into heaps which have accumulated into millions of tons over the years. Moreover, they pose a danger to the environment as they occupy vacant land (space problems). Over the past few years, studies have been conducted to investigate the copper slag-producing outlets to learn their behavior, as well as properties of slag, to have the knowledge of how to better reuse and recycle copper slag. This review article provides the environmental and socioeconomic impacts of slag, as well as a characterization of copper slag, with the aim of reusing and recycling the slag to benefit the environment and economy. Recycling methods are considered an attractive technological pathway for reducing waste and greenhouse gas emissions, as well as promoting the concept of circular economy through the utilization of waste. These metal elements have value depending on their characteristics; hence, copper slag is considered as a secondary source of valuable metals. Some of the pyrometallurgical and hydrometallurgical processes to consider are physical separation, magnetic separation, flotation, leaching, and direct reduction roasting of iron (DRI). Some of the possible metals that can be recovered from the copper slag include Cu, Fe, Ni, Co, and Ag (precious metals).

scholarly journals Leaching of gold and silver from printed circuit board of mobile phones

2015 ◽  
Vol 68 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Patrícia Melo Halmenschlager Petter ◽  
Hugo Marcelo Veit ◽  
Andréa Moura Bernardes
Keyword(s):  
Mobile Phones ◽  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Precious Metals ◽  
Circuit Board ◽  
Circuit Boards ◽  
Aqua Regia ◽  
Printed Circuit ◽  
Ammonium Thiosulfate

Nowadays there is a wide variety of models, sizes and configurations of mobile phones available for consumption. After the life cycle of this equipment, the recycling and reuse of the precious metals found in the printed circuit boards (PCB) of the mobile phones are principal objectives. Thus, the objective of this work was to characterize the gold and silver present in a PCB and develop a recycling route using alternative reagents for cyanide, such as sodium and ammonium thiosulfate. These reagents are less harmful to the environment and worker health. The first characterization of gold and silver was performed with aqua regia. The results show 86.26g Au/ton of PCBs and 123.85g Ag/ton of PCBs. The second characterization was performed with a commercial cyanide-based reagent and 112.02g Au/ton of PCBs and 26.13g Ag/ ton of PCBs were obtained. A leaching study with solutions based on thiosulfate was performed and an extraction of 9.02g Au/ton of PCBs and 33.88g Ag/ton of PCBs was obtained, compared to characterization results using a cyanide-based reagent.

scholarly journals Laboratory testing results of kinetics and processing technology of the polymetallic sulphide concentrate Blagojev Kamen – Serbia

10.30544/220 ◽  
2016 ◽  
Vol 22 (2) ◽  
pp. 117-128
Author(s):  
Milorad Ćirković ◽  
Željko Kamberović ◽  
Mile Bugarin
Keyword(s):  
Laboratory Testing ◽  
Precious Metals ◽  
Raw Material ◽  
Smelting Product ◽  
Kinetics Parameters ◽  
Oxidative Roasting ◽  
Dta Analysis ◽  
Reduction Smelting ◽  
Kinetic Investigations

This work presents the laboratory testing results of kinetics the oxidation process and sample processing of the sulphide polymetallic concentrate Blagojev Kamen. The aim of investigation is recovery of these types of raw material, present in large quantities in the peripheral parts of already used primary mineral deposits of copper, because of their high economic potential due to the content of a large number of metals and especially precious metals. Characterization of this raw material is based on the chemical analyses, XRD results, DTA analysis, etc. For these investigations, the sulphide concentrate with the following content was used in %: Cu – 2.3; Fe – 19.8; S – 27.19; Zn – 9.13; As – 0.167; Pb – 15.63; SiO2 – 17.93; CaO – 0.97; Al2O3 – 1.43; Ag – 480 g/t; Au – 659 g/t. Kinetic investigations of oxidation processes were carried out under the isothermal conditions within the temperature range of 400 to 625 oC. The Sharp's model was used for determination the kinetics parameters, and determined values of activation energy are 67 kJ/mole for the first period, and 47 kJ/mole for the second period. Pyrometallurgical treatment of this type of polymetallic concentrate, in the laboratory conditions, was carried out using the oxidative roasting and, then the reduction smelting was done in the Taman's furnace. Gold from 90.5 to 97.95% and silver from 77.28 to 93.37% are moved into the raw lead (smelting product). Gold from 1.1 to 3.92% and silver from 4.35 to 8.42% are moved into the polymetallic copper matte. Gold from 0.58 to 1.6% and silver from 2.45 to 6.82% are moved into the slag.

scholarly journals Electrocatalytic activity of hypo–hyper-d-electrocatalysts (Me/TiO2/MWCNTs) based on Co-Ru in alkaline hydrogen electrolyser

2011 ◽  
Vol 30 (1) ◽  
pp. 55
Author(s):  
Perica Paunović ◽  
Orce Popovski ◽  
Dafinka Stoevska Gogovska ◽  
Elefteria Lefterova ◽  
Evelina Slavcheva ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Cyclic Voltammetry ◽  
Precious Metals ◽  
Water Electrolysis ◽  
Metallic Phase ◽  
Ftir Analysis ◽  
Excellent Performance ◽  
Multiwalled Carbon ◽  
Potentiodynamic Method

This study is concerned with preparation and characterization of Co-Ru based hypo-hyper d-electrocatalysts aimed for water electrolysis. The composition of the studied electrocatalysts was: 10 % mixed metallic phase (Co : Ru = 1 : 1 wt., Co:Ru = 4 : 1 wt. and Co : Ru : Pt = 4 : 0.5 : 0.5), 18 % TiO2 as a crystalline anatase deposited on activated multiwalled carbon nanotubes (MWCNTs). For comparison, corresponding electrocatalysts with pure hyper d-metallic phase (Co and Ru) were prepared. The structural characterization of the studied electrocatalysts was performed by means of XRD, SEM and FTIR analysis. The prepared hypo-hyper d-electrocatalysts were electrochemically studied by cyclic voltammetry and potentiodynamic method in the alkaline hydrogen electrolyser. The order of the catalytic activity for hydrogen evolution of studied electrocatalysts was the following: Ru > CoRuPt (4 : 0.5 : 0.5, wt.) > CoRu (1 : 1 wt.) > CoRu (4 : 1 wt.) > Co. The electrocatalyst with only 20 % precious metals (Pt and Ru) in the metallic phase (the rest being Co-metal) exhibited excellent performance approaching that of the electrocatalyst with 100 % precious metallic phase (Ru).

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