scholarly journals Precious Metal Distributions Between Copper Matte and Slag at High $$ P_{{{\text{SO}}_{ 2} }} $$ in WEEE Reprocessing

2021 ◽  
Vol 52 (2) ◽  
pp. 871-882
Author(s):  
Min Chen ◽  
Katri Avarmaa ◽  
Lassi Klemettinen ◽  
Hugh O’Brien ◽  
Junjie Shi ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Precious Metal ◽  
Electronic Waste ◽  
Precious Metals ◽  
Matte Grade ◽  
Distribution Coefficients ◽  
Copper Matte ◽  
Copper Smelting ◽  
Gold Silver ◽  
Ar Gas

AbstractThe distributions of precious metals (gold, silver, platinum, and palladium) between copper matte and silica-saturated FeOx-SiO2/FeOx-SiO2-Al2O3/FeOx-SiO2-Al2O3-CaO slags were investigated at 1300 °C and $$ P_{{{\text{SO}}_{ 2} }} $$ P SO 2 = 0.5 atm. The experiments were carried out in silica crucibles under flowing CO-CO2-SO2-Ar gas atmosphere. The concentrations of precious metals in matte and slag were analyzed by Electron Probe X-ray Microanalysis and Laser Ablation-High-Resolution Inductively Coupled Plasma-Mass Spectrometry, respectively. The precious metal concentrations in matte and slag, as well as the distribution coefficients of precious metals between matte and slag, were displayed as a function of matte grade. The present results obtained at $$ P_{{{\text{SO}}_{ 2} }} $$ P SO 2 of 0.5 atm were compared with previous results at $$ P_{{{\text{SO}}_{ 2} }} $$ P SO 2 of 0.1 atm for revealing the effects of $$ P_{{{\text{SO}}_{ 2} }} $$ P SO 2 and selected slag modifiers (CaO and Al2O3) on precious metal distributions at copper matte smelting conditions. The present results also contribute experimental thermodynamic data of precious metal distributions in pyrometallurgical reprocessing of electronic waste via copper smelting processes.

scholarly journals Equilibrium of Copper Matte and Silica-Saturated Iron Silicate Slags at 1300 °C and $$ P_{{{\text{SO}}_{ 2} }} $$ of 0.5 atm

2020 ◽  
Vol 51 (5) ◽  
pp. 2107-2118
Author(s):  
Min Chen ◽  
Katri Avarmaa ◽  
Lassi Klemettinen ◽  
Junjie Shi ◽  
Pekka Taskinen ◽  
...  
Keyword(s):  
Phase Equilibria ◽  
Matte Grade ◽  
Distribution Coefficients ◽  
Iron Silicate ◽  
Copper Matte ◽  
Copper Smelting ◽  
Smelting Process ◽  
Water Mixture ◽  
Data Set ◽  
Ice Water

Abstract Experimental study on the phase equilibria between copper matte with silica-saturated iron silicate slags was conducted at 1300 °C and $$ P_{{{\text{SO}}_{ 2} }} $$ P SO 2 = 0.5 atm. The high-temperature isothermal equilibration in silica crucibles under controlled flowing CO-CO2-SO2-Ar was followed by quenching in an ice–water mixture and direct phase composition analyses by an electron probe X-ray microanalyzer. The equilibrium compositions for matte and slag, as well as the distribution coefficients, were displayed as a function of matte grade. The data set obtained at $$ P_{{{\text{SO}}_{ 2} }} $$ P SO 2 = 0.5 atm and the previous study at $$ P_{{{\text{SO}}_{ 2} }} $$ P SO 2 = 0.1 atm by the authors enabled an investigation on the impacts of $$ P_{{{\text{SO}}_{ 2} }} $$ P SO 2 as well as Al2O3 and CaO additions on phase equilibria in the multiphase copper matte smelting system. Thermodynamic calculations using MTDATA software were performed to compare the experimental results with modeling. The present results enrich the fundamental thermodynamic information for the matte/slag/tridymite/gas equilibria in the primary copper smelting process at high $$ P_{{{\text{SO}}_{ 2} }} $$ P SO 2 .

scholarly journals Behavior of Tin and Antimony in Secondary Copper Smelting Process

Minerals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 39 ◽  
Author(s):  
Lassi Klemettinen ◽  
Katri Avarmaa ◽  
Hugh O’Brien ◽  
Pekka Taskinen ◽  
Ari Jokilaakso
Keyword(s):  
Inductively Coupled Plasma ◽  
Electronic Waste ◽  
Metallic Copper ◽  
Industrial Process ◽  
Distribution Coefficients ◽  
Copper Smelting ◽  
Smelting Process ◽  
Potassium Oxide ◽  
Equilibrium System ◽  
Silicate Slag

Different types of metal-bearing wastes, such as WEEE (Waste Electrical and Electronic Equipment), are important urban minerals in modern society, and the efficient recycling and reuse of their metal values is of key interest. Pyrometallurgical copper smelting is one of the most prominent ways of treating WEEE, however, more accurate experimental data is needed regarding the behavior of different elements during each process stage. This article investigates the behavior of tin and antimony, both commonly present as trace elements in electrical and electronic waste, in secondary (i.e., sulfur-free) copper smelting conditions. The experiments were conducted in oxygen partial pressure range of 10−10–10−5 atm, covering the different process steps in copper smelting. The basis of the equilibrium system was metallic copper–iron silicate slag, with the addition of alumina and potassium oxide to account for the presence of these compounds in the actual industrial process. The results showed that the distribution coefficients of both trace metals, LCu/slag = [wt % Me]copper/(wt % Me)slag, increased significantly as a function of decreasing oxygen pressure, and the addition of basic potassium oxide also had an increasing effect on the distribution coefficient. A brief comparison between EPMA and LA-ICP-MS (electron probe microanalysis and laser ablation–inductively coupled plasma–mass spectrometry), the two in situ analytical techniques used, was also presented and discussed.

Comparison of Leaching Processes of Gold and Copper from Printed Circuit Boards of Waste Mobile Phone

2014 ◽  
Vol 955-959 ◽  
pp. 2743-2746 ◽  
Author(s):  
Jian Feng Yin ◽  
Si Hui Zhan ◽  
He Xu
Keyword(s):  
Mobile Phone ◽  
Inductively Coupled Plasma ◽  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Electronic Waste ◽  
Precious Metals ◽  
Optical Emission ◽  
Optimal Choice ◽  
Circuit Board ◽  
Printed Circuit

Waste mobile phone has become the largest number of electronic waste, and recycling of metals from mobile phone would ensure resource recycling and reduce environmental degradation. Based on the contents of metals analyzed by Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES), containing copper and precious metals such as gold, the paper compared the extraction processes of gold, copper from waste mobile phone printed circuit board (PCB). In this study, two processes, nitric acid and thiourea (NT), sulfuric acid-hydrogen peroxide and iodine (SAHPI) were used to leach copper and gold, respectively. The recovery rate of copper was found to be 96.42%, and 94.3% of the gold was leached in the former process. Similar trends were obtained for the leaching of copper and gold in the latter process, but it was lower that about 95.27% of copper was recycled, while 93.4% of gold were leached. Both the two processes were nontoxic and non-cyanide system. However, thiourea is not stable and easy to decompose in alkaline solution, and the technology has disadvantage of instability. Iodine leaching on the other hand is comparatively a environmental process. Therefore, the optimal choice is the combined process of SAHPI method, while further research is required to develop cost effective and environmentally friendly processes.

scholarly journals Modeling Precious Metal Returns through Fractional Jump-Diffusion Processes Combined with Markov Regime-Switching Stochastic Volatility

Mathematics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 407
Author(s):  
Martha Carpinteyro ◽  
Francisco Venegas-Martínez ◽  
Alí Aali-Bujari
Keyword(s):  
Decision Making ◽  
Stochastic Volatility ◽  
Regime Switching ◽  
Precious Metal ◽  
Precious Metals ◽  
Stochastic Volatility Model ◽  
Decision Making Process ◽  
Markov Regime Switching ◽  
Volatility Model ◽  
Gold Silver

This paper is aimed at developing a stochastic volatility model that is useful to explain the dynamics of the returns of gold, silver, and platinum during the period 1994–2019. To this end, it is assumed that the precious metal returns are driven by fractional Brownian motions, combined with Poisson processes and modulated by continuous-time homogeneous Markov chains. The calibration is carried out by estimating the Jump Generalized Autoregressive Conditional Heteroscedasticity (Jump-GARCH) and Markov regime-switching models of each precious metal, as well as computing their Hurst exponents. The novelty in this research is the use of non-linear, non-normal, multi-factor, time-varying risk stochastic models, useful for an investors’ decision-making process when they intend to include precious metals in their portfolios as safe-haven assets. The main empirical results are as follows: (1) all metals stay in low volatility most of the time and have long memories, which means that past returns have an effect on current and future returns; (2) silver and platinum have the largest jump sizes; (3) silver’s negative jumps have the highest intensity; and (4) silver reacts more than gold and platinum, and it is also the most volatile, having the highest probability of intensive jumps. Gold is the least volatile, as its percentage of jumps is the lowest and the intensity of its jumps is lower than that of the other two metals. Finally, a set of recommendations is provided for the decision-making process of an average investor looking to buy and sell precious metals.

scholarly journals Evaluation of the Environmental Impacts of Electronic-Waste Management in Lagos Using Alaba International Market and Ikeja Computer Village as Case Studies

2020 ◽  
Vol 4 (2) ◽  
pp. 283-297
Author(s):  
R. Alani ◽  
A. Ogunbanmwo ◽  
D. Nwude ◽  
M. Ogbaje
Keyword(s):  
Waste Management ◽  
Water Samples ◽  
Flame Retardants ◽  
Electronic Waste ◽  
Precious Metals ◽  
International Market ◽  
Platinum Group Metals ◽  
Additional Information ◽  
Waste Dumps ◽  
Gold Silver

The main aim of this research was to assess the extent of the problems associated with inappropriate e-waste management and recycling practices. Electronic wastes (E-wastes) are generated from products that are designed for use with a maximum voltage of 1000 volts for alternating current and 1500 volts for direct current. These wastes contain hazardous materials such as lead, mercury, cadmium, brominated flame-retardants, valuable metals such as aluminium, nickel, copper, and certain precious metals such as gold, silver and platinum group metals (PGMs) which pose both human and environmental health threats. They have negative impacts on the health of workers and nearby residents; hence, residents of buildings located around and beside e-wastes dumpsites were randomly selected for this study. Well, run-off and borehole water samples as well as soil samples from different sites in Alaba international market, and Ikeja computer village in Lagos, Nigeria were analyzed for zinc, lead, iron, copper, nickel and chromium. Using additional information from questionnaires and interviews, impacts of e-waste dumps on the health of workers and residents near the study areas were investigated. The results were analysed using descriptive frequency count and tables which confirmed the presence of heavy metals in soils and water samples of the case study areas and hence appropriate recommendations were outlined to address the menace of e-waste disposal and as well as the need for improvement in e-waste management and recycling for economic opportunities and improved health standard within the Lagos Metropolis.

Interaction between precious metals price and Islamic stock markets

2019 ◽  
Vol 12 (1) ◽  
pp. 96-114 ◽  
Author(s):  
Gülfen Tuna
Keyword(s):  
Stock Markets ◽  
Precious Metal ◽  
Precious Metals ◽  
Panel Cointegration ◽  
Cointegration Analysis ◽  
Portfolio Diversification ◽  
Content Type ◽  
Gold Silver ◽  
Practical Implications

Purpose This study aims to analyze the presence of a long-term relationship between precious metal prices, such as for gold, silver, platinum and palladium, and Islamic stock markets of 32 different countries – 21 developed and 11 developing. In this study, the long-term relationship between the precious metal prices and the Islamic stock markets of countries grouped by the Morgan Stanley Capital Index (MSCI) according to their level of development was examined. In the economies included in the study, it is necessary that the Islamic stock index be created by MSCI. It is not a constraint as a Muslim country. Design/methodology/approach This study used the Pedroni panel cointegration analysis and full modified ordinary least square method. All analyses in this study were performed using monthly data from 2002 to 2015. Findings According to the Pedroni panel cointegration analysis applied in this study, all four precious metals – gold, silver, platinum and palladium – are effective portfolio diversification tools for developed Islamic stock markets within the analyzed period. However, in developing countries, although gold and palladium are effective portfolio diversification tools, silver and platinum are not. Practical implications These results provide practical implications for academicians, practitioners as portfolio managers, policymakers. These implications are related in portfolio risk management, the diversification benefits and to propose new investment tools among developed and developing Islamic markets. Social implications This study is important for investors who assemble portfolios under the restriction of selecting investment tools suitable for Islamic rules. These investors are important in terms of using precious metals that they prefer as an alternative to stock markets to protect against the risks related to their suitable portfolio options. Governments, individuals and institutional investors that use capital stock according to Islamic rules in developed countries can effectively use gold, silver, platinum and palladium as hedging tools. However, this choice is limited to only gold and palladium in developing country markets. Gold continues to be an effective diversification tool in Islamic share markets, as in traditional stock markets. Originality/value The author would like to emphasize that this article is second to examine precious metals and Islamic stock markets in literature.

Analysis of Selected Seasonality Effects in the Following Metal Markets: Gold, Silver, Platinum, Palladium and Copper

2019 ◽  
pp. 59-86
Author(s):  
Krzysztof Borowski ◽  
Małgorzata Łukasik
Keyword(s):  
Financial Markets ◽  
Precious Metal ◽  
Precious Metals ◽  
Weekend Effect ◽  
Commodity Market ◽  
Metal Exchange ◽  
London Metal Exchange ◽  
Interesting Phenomenon ◽  
Gold Silver ◽  
Day Of The Week

The commodity market has been becoming one of the most popular segments of the financial markets among individual and institutional investors in recent years. Similarly to the eąuity market, the problem of anomalies in the commodities market is becoming an interesting phenomenon, especially in the segment of the precious metals. This paper tests the hypothesis of monthly, the day-of-the week and weekend effects of the precious metal markets ąuoted on the London Metal Exchange for gold, silver, platinum and copper in the period of 1.01.1995-31.12.2015 considering also palladium in the period 1.01.1998-31.12.2015. Calculations presented in this paper indicate the absence of the monthly effect on gold, silver, platinum, copper markets but proved occurrence of monthly anomaly in the month of September on palladium market. In the analyzed period day- of-the week effect for any of the studied metal markets was not observed but the weekend effect was registered on the gold and copper markets.

Preparation a Scrap of the Electronic Enterprises and its Subsequent Processing

2020 ◽  
Vol 303 ◽  
pp. 79-88
Author(s):  
D.V. Shmidt ◽  
Bashar Issa ◽  
V.Yu. Timofeev
Keyword(s):  
Electronic Waste ◽  
Precious Metals ◽  
Environmental Standards ◽  
Advantages And Disadvantages ◽  
Nickel Zinc ◽  
Ferrous Metals ◽  
Gold Silver ◽  
Valuable Metals ◽  
Electrical Devices ◽  
Modern Technologies

The processing conditions of the of electronic wastes are largely dependent on environmental standards and requirements. Modern technologies for processing electronic waste should meet the increased demand for metals as well as the requirements. Electronic wastes can be classified as hazardous materials, as household and industrial electrical devices, which contain components such as batteries, capacitors, cathode ray tubes, etc. Electronic waste can consist of a large number of components of various sizes, shapes and chemical composition. Some of them contain hazardous metals, including mercury, lead, cadmium. The presence of precious metals in electronic waste such as gold, silver, platinum, palladium, as well as non-ferrous metals (copper, nickel, zinc, tin, etc.) make it attractive for processing. In industry, both hydrometallurgical and pyrometallurgical methods are used to extract valuable metals from electronic waste. Applied technologies may have both advantages and disadvantages.

scholarly journals Urban mining by flash Joule heating

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Bing Deng ◽  
Duy Xuan Luong ◽  
Zhe Wang ◽  
Carter Kittrell ◽  
Emily A. McHugh ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Joule Heating ◽  
Circular Economy ◽  
Precious Metal ◽  
Electronic Waste ◽  
Precious Metals ◽  
Metal Component ◽  
Urban Mining ◽  
Agriculture Soil ◽  
Temperature Ramps

AbstractPrecious metal recovery from electronic waste, termed urban mining, is important for a circular economy. Present methods for urban mining, mainly smelting and leaching, suffer from lengthy purification processes and negative environmental impacts. Here, a solvent-free and sustainable process by flash Joule heating is disclosed to recover precious metals and remove hazardous heavy metals in electronic waste within one second. The sample temperature ramps to ~3400 K in milliseconds by the ultrafast electrical thermal process. Such a high temperature enables the evaporative separation of precious metals from the supporting matrices, with the recovery yields >80% for Rh, Pd, Ag, and >60% for Au. The heavy metals in electronic waste, some of which are highly toxic including Cr, As, Cd, Hg, and Pb, are also removed, leaving a final waste with minimal metal content, acceptable even for agriculture soil levels. Urban mining by flash Joule heating would be 80× to 500× less energy consumptive than using traditional smelting furnaces for metal-component recovery and more environmentally friendly.

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