Electrolytic recovery of antimony from natural stibnite ore
Loutfy H. Madkour a, *, Ibrahim A. Salem b
a Chemistry Department, Faculty of Science, Tanta University, Tanta, Egypt b Geology Department, Faculty of Science, Tanta University, Tanta, Egypt
Received l0 November 1995; accepted 6 December 1995
Abstract
Stibnite ore at Wadi Abu Quraiya, situated in the central Eastern Desert of Egypt has been subjected to petrographical, mineralogical, infrared, X-ray diffraction, chemical and spectral analyses. Hydrometallurgical treatment based on leaching with acids, precipitation and electrode- position of metal values from the ore have been developed. Studies to investigate suitable electrolytic baths for the cathodic deposition of metallic antimony either directly from the leach liquor or in the presence of complexing agents have been carded out. The influence of various factors on the electrodeposition process of the element from its electrolyte solutions is discussed. Advantages of the flowsheet and various approaches depending on convenient electrolytes for the deposition of antimony from the stibnite ore have been investigated. The results of spectrophoto- metric and chemical analyses revealed that the purity of the metal is > 99%.
Experimental and Theoretical Investigation of Thiazolyl Blue as a Corrosion I...Al Baha University
The anticorrosion effect of thiazolyl blue (MTT) for copper in 3% NaCl at 298 K
was researched by electrochemical methods, scanning electron-microscopy (SEM), and atomic
force microscopy (AFM). The results reveal that MTT can protect copper efficiently, with a
maximum efficiency of 95.7%. The corrosion inhibition mechanism was investigated by X-ray
photoelectron spectroscopy (XPS), Fourier transform infrared spectral (FT-IR), and theoretical
calculation. The results suggest that the MTT molecules are adsorbed on metal surface forming a
hydrophobic protective film to prevent copper corrosion. It also indicates that the MTT and copper
form covalent bonds. The molecular dynamic simulation further gives the evidence for adsorption.
The adsorption isotherm studies demonstrate that a spontaneous, mixed physical and chemical
adsorption occurs, which obeys Langmuir adsorption isotherm. The present research can help us
better understand the corrosion inhibition process and improve it.
Eco-friendly method for the estimation of cobalt (II) in real samples using 1...Innspub Net
An easy and quick spectrophotometric method is developed for the investigation of cobalt at trace level using 1-(2-Thiazolylazo)-2-naphthol (TAN) in presence of surfactant cetyltrimethylammonium bromide (CTAB) aqueous micellar solution. The cobalt forms bis [1-(2-Thiazolylazo)-2-naphthol] cobalt complex reacting with 1-(2-Thiazolylazo)-2-naphthol. Proposed method is of great importance because use of micellar system instead of solvent extraction steps that were toxic, expensive and time consuming. The method shows improved sensitivity, selectivity and molar absorption. The coefficient of molar absorption and Sandell’s sensitivity was found to be ε 1.89 × 104L mol-1 cm-1 and 3.1ngcm-2 at λmax 572.7nm. Graph of Linear concentration calibration was obtained in the range 0.02-9.0μgmL-1; stoichiometric metal ligand ratio was found 1:2 for the complex Co-[TAN]2 formation. The proposed method was applied for the investigation of cobalt from different alloys, biological, environmental and pharmaceutical samples. Full articles at https://lnkd.in/fbEHTJ6
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Experimental and Theoretical Investigation of Thiazolyl Blue as a Corrosion I...Al Baha University
The anticorrosion effect of thiazolyl blue (MTT) for copper in 3% NaCl at 298 K
was researched by electrochemical methods, scanning electron-microscopy (SEM), and atomic
force microscopy (AFM). The results reveal that MTT can protect copper efficiently, with a
maximum efficiency of 95.7%. The corrosion inhibition mechanism was investigated by X-ray
photoelectron spectroscopy (XPS), Fourier transform infrared spectral (FT-IR), and theoretical
calculation. The results suggest that the MTT molecules are adsorbed on metal surface forming a
hydrophobic protective film to prevent copper corrosion. It also indicates that the MTT and copper
form covalent bonds. The molecular dynamic simulation further gives the evidence for adsorption.
The adsorption isotherm studies demonstrate that a spontaneous, mixed physical and chemical
adsorption occurs, which obeys Langmuir adsorption isotherm. The present research can help us
better understand the corrosion inhibition process and improve it.
Eco-friendly method for the estimation of cobalt (II) in real samples using 1...Innspub Net
An easy and quick spectrophotometric method is developed for the investigation of cobalt at trace level using 1-(2-Thiazolylazo)-2-naphthol (TAN) in presence of surfactant cetyltrimethylammonium bromide (CTAB) aqueous micellar solution. The cobalt forms bis [1-(2-Thiazolylazo)-2-naphthol] cobalt complex reacting with 1-(2-Thiazolylazo)-2-naphthol. Proposed method is of great importance because use of micellar system instead of solvent extraction steps that were toxic, expensive and time consuming. The method shows improved sensitivity, selectivity and molar absorption. The coefficient of molar absorption and Sandell’s sensitivity was found to be ε 1.89 × 104L mol-1 cm-1 and 3.1ngcm-2 at λmax 572.7nm. Graph of Linear concentration calibration was obtained in the range 0.02-9.0μgmL-1; stoichiometric metal ligand ratio was found 1:2 for the complex Co-[TAN]2 formation. The proposed method was applied for the investigation of cobalt from different alloys, biological, environmental and pharmaceutical samples. Full articles at https://lnkd.in/fbEHTJ6
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Facile fabrication and characterizations of nanostructured Fe2O3-TiO2 composi...IJAEMSJORNAL
Fe2O3-TiO2 nanoparticles promises as a highly effective material for adsorption of heavy metals and used as photocatalyst for the removal of organic dye pollutants. In this study, nanostructured Fe2O3-TiO2 composite was successfully fabricated by one-step reaction of ilmenite ore at the high temperature in ambient condition. The resultant Fe2O3-TiO2 composite was characterized by using X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), nitrogen adsorption-desorption isotherm. The effects of sintered temperature and time on the formation of the Fe2O3-TiO2 nanocomposite were investigated in detail. The Fe2O3-TiO2 was formed from ilmenite ore after calcination at the temperature of 700oC in 3 hours, followed by a ball-milled process in 4 hours. The obtained Fe2O3-TiO2 composite has an average diameter of from 50 - 100 nm with the BET surface area of 7 m2/g.
Synthesis, characterization and electrocatalytic activity of silver nanorods ...kutty79
This paper describes a simple method of synthesizing silver nanorods using the polyol process, where propylene glycol serves both as a reducing
agent and as a solvent in the presence of a capping reagent such as polyvinylpyrrolidone (PVP). The diameter and length of silver nanorods could be
controlled by changing the AgNO3/PVP ratio. The end-to-end assembly of the silver nanorods was found. The silver nanorods were characterized by
using scanning electron microscopy, transmission electron microscopy, X-ray diffraction and absorption spectroscopy. The catalytic activity of a
glassy carbon electrode with Ag nanorods exhibits extraordinary electrocatalytic activities towards the electro-reduction of benzyl chloride.
Done by: Sukari group
School name; Omar Bin Khattab secondary school for boys.
The project aimed to study how the investigated triazole derivative controls the corrosion of mild steel in sulfuric acid solutions. The corrosion rates in absence and presence of different concentrations of inhibitor will be measured using weight loss and potentiodynamic polarization techniques. Also, the effect of inhibitor on surface morphology of carbon steel will be investigated using scanning electron microscope.
A Simple Thermal Treatment Synthesis and Characterization of Ni-Zn Ferrite (N...IOSR Journals
Cubic structured nickel-zinc ferrite nanoparticles (Ni0.5Zn0.5Fe2O4) have been synthesized by thermal treatment method. This simple procedure employed an aqueous solution containing only metal nitrates as precursors, polyvinyl pyrrolidone as a capping agent, and deionized water as a solvent. The solution was thoroughly stirred for 2 hour, dried at 353 K for 3 hour, the dried material crushed into powder and calcined the powder at 873 K to remove organic substances and crystallize the particles. The microstructure properties of the prepared ferrite nanoparticles were measured using FTIR, XRD, TEM, and EDX and the magnetic properties were determined using VSM and EPR. The average particle size increased from 7 to 22 nm with the increase of calcination temperature from 723 to 873 K. The saturation magnetization, coercivity field, and g-factor increased respectively from 24 emu/g, 11 G, and 2.0673at 723 K to 38 emu/g, 60 G, and 2.1227 at 873 K. This method offers simplicity, a low cost, and an environmentally friendly operation since it produces no by-product effluents.
Ginger extract as corrosion inhibitor from natural resources was studied to prevent corrosion of mild steel in acid media. Ginger rhizome was extracted to produce green corrosion inhibitor (G-1) while ginger powder bought at supermarket was also extracted to form a green corrosion inhibitor (G-2). Effectiveness of inhibitor in preventing corrosion process of mild steel was studied in 1.0 M of hydrochloric acid
General principles and process of isolation of elements (STD 12 SCIENCE) lec...MAYURI SOMPURA
CONCENTRATION OF ORES
EXTRACTION OF CRUDE METAL FROM ORE
ISOLATION OF ELEMENTS
PRINCIPLES OF ISOLATION
HYDRAULIC WASHING
FORTH FLOATATION METHOD
MAGNETIC SEPERATION
LEACHING
CALCINATION
ROASTING
Facile fabrication and characterizations of nanostructured Fe2O3-TiO2 composi...IJAEMSJORNAL
Fe2O3-TiO2 nanoparticles promises as a highly effective material for adsorption of heavy metals and used as photocatalyst for the removal of organic dye pollutants. In this study, nanostructured Fe2O3-TiO2 composite was successfully fabricated by one-step reaction of ilmenite ore at the high temperature in ambient condition. The resultant Fe2O3-TiO2 composite was characterized by using X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), nitrogen adsorption-desorption isotherm. The effects of sintered temperature and time on the formation of the Fe2O3-TiO2 nanocomposite were investigated in detail. The Fe2O3-TiO2 was formed from ilmenite ore after calcination at the temperature of 700oC in 3 hours, followed by a ball-milled process in 4 hours. The obtained Fe2O3-TiO2 composite has an average diameter of from 50 - 100 nm with the BET surface area of 7 m2/g.
Synthesis, characterization and electrocatalytic activity of silver nanorods ...kutty79
This paper describes a simple method of synthesizing silver nanorods using the polyol process, where propylene glycol serves both as a reducing
agent and as a solvent in the presence of a capping reagent such as polyvinylpyrrolidone (PVP). The diameter and length of silver nanorods could be
controlled by changing the AgNO3/PVP ratio. The end-to-end assembly of the silver nanorods was found. The silver nanorods were characterized by
using scanning electron microscopy, transmission electron microscopy, X-ray diffraction and absorption spectroscopy. The catalytic activity of a
glassy carbon electrode with Ag nanorods exhibits extraordinary electrocatalytic activities towards the electro-reduction of benzyl chloride.
Done by: Sukari group
School name; Omar Bin Khattab secondary school for boys.
The project aimed to study how the investigated triazole derivative controls the corrosion of mild steel in sulfuric acid solutions. The corrosion rates in absence and presence of different concentrations of inhibitor will be measured using weight loss and potentiodynamic polarization techniques. Also, the effect of inhibitor on surface morphology of carbon steel will be investigated using scanning electron microscope.
A Simple Thermal Treatment Synthesis and Characterization of Ni-Zn Ferrite (N...IOSR Journals
Cubic structured nickel-zinc ferrite nanoparticles (Ni0.5Zn0.5Fe2O4) have been synthesized by thermal treatment method. This simple procedure employed an aqueous solution containing only metal nitrates as precursors, polyvinyl pyrrolidone as a capping agent, and deionized water as a solvent. The solution was thoroughly stirred for 2 hour, dried at 353 K for 3 hour, the dried material crushed into powder and calcined the powder at 873 K to remove organic substances and crystallize the particles. The microstructure properties of the prepared ferrite nanoparticles were measured using FTIR, XRD, TEM, and EDX and the magnetic properties were determined using VSM and EPR. The average particle size increased from 7 to 22 nm with the increase of calcination temperature from 723 to 873 K. The saturation magnetization, coercivity field, and g-factor increased respectively from 24 emu/g, 11 G, and 2.0673at 723 K to 38 emu/g, 60 G, and 2.1227 at 873 K. This method offers simplicity, a low cost, and an environmentally friendly operation since it produces no by-product effluents.
Ginger extract as corrosion inhibitor from natural resources was studied to prevent corrosion of mild steel in acid media. Ginger rhizome was extracted to produce green corrosion inhibitor (G-1) while ginger powder bought at supermarket was also extracted to form a green corrosion inhibitor (G-2). Effectiveness of inhibitor in preventing corrosion process of mild steel was studied in 1.0 M of hydrochloric acid
General principles and process of isolation of elements (STD 12 SCIENCE) lec...MAYURI SOMPURA
CONCENTRATION OF ORES
EXTRACTION OF CRUDE METAL FROM ORE
ISOLATION OF ELEMENTS
PRINCIPLES OF ISOLATION
HYDRAULIC WASHING
FORTH FLOATATION METHOD
MAGNETIC SEPERATION
LEACHING
CALCINATION
ROASTING
INHIBITION EFFECT OF SCHIFF BASE COMPOUNDS ON THE CORROSION OF IRON IN NITRIC ACID AND SODIUM HYDROXIDE SOLUTIONS
Loutfy H. Madkour* and U.A. Zinhome**
This presentation is on how to create a LinkedIn Power Profile. The presentation has several resources at the end as well as a list of LinkedIn Experts and some of my favorite books on LinkedIn.
Electrolytic recovery of antimony from natural stibnite ore Al Baha University
Stibnite ore at Wadi Abu Quraiya, situated in the central Eastern Desert of Egypt has been subjected to petrographical, mineralogical, infrared, X-ray diffraction, chemical and spectral analyses. Hydrometallurgical treatment based on leaching with acids, precipitation and electrode- position of metal values from the ore have been developed. Studies to investigate suitable electrolytic baths for the cathodic deposition of metallic antimony either directly from the leach liquor or in the presence of complexing agents have been carded out. The influence of various factors on the electrodeposition process of the element from its electrolyte solutions is discussed. Advantages of the flowsheet and various approaches depending on convenient electrolytes for the deposition of antimony from the stibnite ore have been investigated. The results of spectrophoto- metric and chemical analyses revealed that the purity of the metal is > 99%.
Keywords: stibnite; leaching; antimony extraction
ELECTRODEPOSITION OF TITANIUM AND ITS DIOXIDE FROM ILMENITE Al Baha University
The aim of the present work was to develop a simple and rapid electrolytic extraction process of titanium [l-3] and its dioxide from the ilmenite ore of the Eastern Desert. The ore mother liquor used for the electrolysis process is either produced by direct leaching with 98% H,SO, (S/L = 1 : 15), 35% HCl (S/L = 1: 20) and alkaline digestion with caustic soda in a ball-mill autoclave at 175°C under a pressure of 9.5 kg cmP2, or it is prepared through the fusion method using NaOH or Na,S,O, separately as fluxes at 600-700°C.
Extraction of Silver From Photographic Waste--and their toxic effects and analysis of the amount is silver extracted from x-ray waste,methods of analysis of amount of toxic silver
Madkour 1985-journal of-chemical_technology_and_biotechnology._chemical_techn...Al Baha University
Recommended Flowsheets for the Electrolytic Extraction of Lead and Zinc from Red Sea Polymetal Ore
The polymetal complex ore Umm-Gheig considered in Egypt as a rather rich source of lead and zinc is subjected to mineralogical, chemical, spectral, X-ray and differential thermal analyses. Hydrometallurgical treatments based on leaching, precipitation and electrodeposition of metal from the ore are established. The influences of current density, temperature and metal ion concentration on the Faradic current efficiency are discussed. Advantages and disadvantages of flow- sheets and various approaches depending on convenient baths for the electro- deposition of metals are investigated. The results of electron microscopic investiga- tion confirmed by metal value data given in the A.S.T.M. cards coincide well with those given by chemical analysis.
ELECTRODEPOSITION OF TITANIUM AND ITS DIOXIDE FROM ILMENITE Al Baha University
The aim of the present work was to develop a simple and rapid electrolytic extraction process of titanium [l-3] and its dioxide from the ilmenite ore of the Eastern Desert. The ore mother liquor used for the electrolysis process is either produced by direct leaching with 98% H,SO, (S/L = 1 : 15), 35% HCl (S/L = 1: 20) and alkaline digestion with caustic soda in a ball-mill autoclave at 175°C under a pressure of 9.5 kg cmP2, or it is prepared through the fusion method using NaOH or Na,S,O, separately as fluxes at 600-700°C.
EXPERIMENTAL
Synthesis of citrate-capped gold nanoparticles from reduced [AuCl4 ]– on asco...UniversitasGadjahMada
Reductive adsorption of [AuCl4]-– by using ascorbic acid immobilized on Mg/Al hydrotalcite (Mg/Al HT) and synthesis of gold nanoparticles (AuNPs) from the reduced gold using sodium citrate have been conducted. Mg/Al HT was synthesized by co-precipitation method at pH 10 with molar ratio of Mg(II) and Al(III) 2:1. Ascorbic acid (AA) was then immobilized on Mg/Al HT to form hybrid of AA and Mg/Al HT (Mg/Al HT-AA). Mg/Al HT-AA was used to reductively adsorb [AuCl4]– and the formed Au(0) was extracted by using sodium citrate to form citrate-capped AuNPs. The formation of AuNPs from 100 mg/L [AuCl4]– solution removed by 60 mg Mg/Al HT-AA was optimum at pH 5.0, by using 70 mM sodium citrate and 2 h sonication time. This optimum condition was successfully applied to synthesize AuNPs from [AuCl4]– as the leaching product of gold from PCB using aquaregia
Kinetics Etude of the Experimental Leaching of Sphalerite Using Acidic Lixivi...CrimsonPublishersAMMS
The influence of physico-chemical parameters such as acid concentration, temperature, particle size and time of leaching on the chemical dissolution of the sphalerite ore in sulfuric acid was examined. At a temperature of 358 K by 2 mol.l-1 H2SO4, a stirring speed of 300 rpm, initial solid / liquid ratio of 10 g/L and particle size (-125 +63^m), about 99 % of zinc was extracted inside 120min. The experimental data of this leaching technique was established by way of the shrinking core model under chemically reaction controlled processes, the corresponding activation energy for the recovery of zinc Ea calculated from the Arrhenius expression to be 18.63kJ/mole.
Synopsis for Recovery of precious metals from electronic scrapAneel Ahmad
Development of non-hazardous process for leaching of metals from electronic scrap and their characterization. Basics of leaching and processes you need to know before choosing process. Merits and demerits of different leaching process.
Introduction to Non ferrous metal extraction, extraction of copper, zink, plumbum, Nickel, Magnesium, Aluminium, Zirconium,Titanium, Stansium, Niobium, Uranium in pyrometallurgical routes.
Synthesis of Silver Nano Particles Ag NPs and their uses in Quantitative Anal...ijtsrd
In this Research Paper silver nanoparticles Ag NPs were prepared by using chemical synthesis method. Silver nanocolloid solution has been prepared by the reduction of silver salt using sodium borohydride NaBH4 and trisodium citrate C6H5Na3O7.2H2O . Triangular silver nanoplates were prepared by reducing silver salt using ascorbic acid. Silver Salt acts as reducing agent. The nanoparticles were characterized by using UV VIS spectrophotometry and Scanning Electron Microscopy SEM . The reducing character of ascorbic acid was used to find the amount of ascorbic acid in vitamin C tablet. Vikram R Patil | R R Gaikwad "Synthesis of Silver Nano Particles (Ag-NPs) and their uses in Quantitative Analysis of Vitamin C Tablet" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-6 | Issue-5 , August 2022, URL: https://www.ijtsrd.com/papers/ijtsrd51700.pdf Paper URL: https://www.ijtsrd.com/chemistry/other/51700/synthesis-of-silver-nano-particles-agnps-and-their-uses-in-quantitative-analysis-of-vitamin-c-tablet/vikram-r-patil
SEMICONDUCTIVITY BEHAVIOUR OF EGYPTIAN NATURAL SINTERED OREAl Baha University
Journal of the University of Chemical Technology and Metallurgy, 45, 3, 2010, 335-346
SEMICONDUCTIVITY BEHAVIOUR OF EGYPTIAN NATURAL SINTERED ORE
FOR THERMOTECHNOLOGICAL APPLICATIONS
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
The increased availability of biomedical data, particularly in the public domain, offers the opportunity to better understand human health and to develop effective therapeutics for a wide range of unmet medical needs. However, data scientists remain stymied by the fact that data remain hard to find and to productively reuse because data and their metadata i) are wholly inaccessible, ii) are in non-standard or incompatible representations, iii) do not conform to community standards, and iv) have unclear or highly restricted terms and conditions that preclude legitimate reuse. These limitations require a rethink on data can be made machine and AI-ready - the key motivation behind the FAIR Guiding Principles. Concurrently, while recent efforts have explored the use of deep learning to fuse disparate data into predictive models for a wide range of biomedical applications, these models often fail even when the correct answer is already known, and fail to explain individual predictions in terms that data scientists can appreciate. These limitations suggest that new methods to produce practical artificial intelligence are still needed.
In this talk, I will discuss our work in (1) building an integrative knowledge infrastructure to prepare FAIR and "AI-ready" data and services along with (2) neurosymbolic AI methods to improve the quality of predictions and to generate plausible explanations. Attention is given to standards, platforms, and methods to wrangle knowledge into simple, but effective semantic and latent representations, and to make these available into standards-compliant and discoverable interfaces that can be used in model building, validation, and explanation. Our work, and those of others in the field, creates a baseline for building trustworthy and easy to deploy AI models in biomedicine.
Bio
Dr. Michel Dumontier is the Distinguished Professor of Data Science at Maastricht University, founder and executive director of the Institute of Data Science, and co-founder of the FAIR (Findable, Accessible, Interoperable and Reusable) data principles. His research explores socio-technological approaches for responsible discovery science, which includes collaborative multi-modal knowledge graphs, privacy-preserving distributed data mining, and AI methods for drug discovery and personalized medicine. His work is supported through the Dutch National Research Agenda, the Netherlands Organisation for Scientific Research, Horizon Europe, the European Open Science Cloud, the US National Institutes of Health, and a Marie-Curie Innovative Training Network. He is the editor-in-chief for the journal Data Science and is internationally recognized for his contributions in bioinformatics, biomedical informatics, and semantic technologies including ontologies and linked data.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
2. 266 L.H. Madkour, 1.4. Salem / Hydrometallurgy 43 (1996)265-275
Quraiya area has been studied in a number of reviews and research reports over the
years [2-4]. Most antimony deposits principally occur as either stibnite or native
antimony in siliceous gangue minerals commonly associated with pyrite and are formed
from hydrothermal solutions [5]. Antimony is recovered by reduction of the stibnite with
iron scrap, direct reduction of natural oxide ores and also from lead base battery scrap
metal. Antimony metal finds extensive industrial applications in the preparation of
hardening alloys for lead, pyrotechnics and semiconductor technology (99.999% grade).
Electrodeposition of metallic antimony (cathodically) might be possible from suitable
electrolyte solutions [6-8]. The aim of the present work was to develop a simple and
rapid method for the electrolytic extraction of antimony metal from stibnite, through
acid leaching and the use of complexing agents.
2. Experimental
2.1. Sampling
A total of 10 surface samples were collected along two traverses crossing the
stibnite-bearing quartz vein. Samples were split, crushed and then ground to pass 100
mesh (0.15 mm). The ground samples were analysed for the quantitative determination
of some major and trace elements. Mineralised stibnite ore was crushed to 100% minus
1.0 mm.
2.2. Chemical and spectral analyses
Spectrographic analysis of the ore sample was carried out at the Geology and
Prospecting Institute, Moscow, Russia. Ore mineralogical studies using polarized and
reflected light microscopy, scanning electron microscopy, X-ray diffraction and infrared
spectroscopic analysis were carried out on the stibnite ore sample in the Central
Laboratory at Tanta University, Egypt.
2.3. Leaching methods
Three different direct leaching agents were used for treatment of the stibnite ore:
Mixture of hydrochloric and tartaric acids: A sample of 1 g of the ore was
decomposed by boiling in 25 ml concentrated hydrochloric acid and 25 ml (20%)
tartaric acid until the mineral was completely decomposed. The insoluble residue was
removed by filtration and washed with a 0.5% tartaric acid solution in 5% HC1.
Mixture of nitric and tartaric acids: 20 ml (20%) tartaric acid was poured over a 0.5
g sample of the ore followed by 20 ml of concentrated HNO 3 acid and the mixture
allowed to stand for 12 h at room temperature, followed by heating on a water bath for 3
h, until the sample had been completely decomposed. The insoluble residue was
separated by filtration and washed with a 0.3% tartaric acid solution in 2% nitric acid.
Hot concentrated sulphuric acid: The decomposition was carried out in a small
conical flask covered with a short-stem funnel; 20 ml of concentrated H2SO 4 was
3. L.H. Madkour, 1.,4. Salem/Hydrometallurgy 43 (1996)265-275 267
poured over a 0.5 g sample and spread over the bottom of the flask by a rotating motion.
The flask was heated gently at first, the temperature was then gradually raised to boiling
point. The decomposition was complete when the dark-coloured ore sample disappeared
and the residue was white. After cooling, the mixture was carefully diluted with about
100 ml H20 added in small portions. A small amount of tartaric acid was added to the
solution to avoid the hydrolysis of antimony and tin in the mineral. The solution was
boiled for about 30 min to dissolve the sulphates of iron and non-ferrous metals
completely. The insoluble residue was filtered and washed well with 1% H2SO 4
solution.
2.4. Preparation of antimony complex salt ore electrolytes
Antimony exists in the leach liquor as trichloride, which forms antimony oxychloride
with water. A standard solution of antimony oxychloride (SbOC1) was prepared and its
concentration determined [9]. For each experiment 0.35-0.90 g antimony chloride in
solution was electrolysed in the presence of the appropriate quantity of a complexing
agent with constant agitation. The total volume of the electrolyte was 100 ml.
2.5. Analytical methods
X-ray diffraction analyses were carried out using a PW 1840 Phillips diffractometer
with CuK~ radiation (hl.5418). Infrared absorption analysis was done using a Perkin
Elmer 683 infrared spectrophotometer; the potassium bromide pellet method was used.
These analyses were carried out at the Central Laboratory, Tanta University, Egypt.
2.6. Apparatus and working procedures for electrolysis
The electrolytic cell design and general experimental procedure were the same as
described elsewhere [10-14]. The cathode was a platinum sheet with an area of 10 cm 2.
The electrolyte temperature was maintained at 25 + I°C with constant stirring in all
experiments. All chemicals used were of Analar quality and were used without further
purification.
3. Results and discussion
3.1. Characteristics of stibnite ore sample
Mineralogically, the stibnite vein lode has a simple mineral assemblage and consists
exclusively of quartz and stibnite. Tetrahedrite, pyrite, chalcopyrite and sphalerite are
sparse and present as inclusions in the quartz and stibnite. Cervantite is a secondary
mineral formed from the oxidation of stibnite. Goethite also occurs. Quartz is the
predominant gangue mineral and occurs as subhedral to anhedral crystals ranging from
0.2 to 0.6 mm in diameter. Quartz may be colourless or stained yellow due to
replacement by goethite. It is frequently fractured, brecciated and exhibits wavy
extinction.
4. 268 L.H. Madkour, LA. Salem/Hydrometallurgy 43 (1996)265-275
Fig. 1. Large irregular crystal of stibnite rimmed by cervantite (reflected light × 75).
Stibnite is the main ore mineral and occupies about 40% of the total mineral
constituents. It occurs either as medium to coarse rounded crystals of about 0.5 to 6 mm
in diameter or as short prismatic crystals ranging in size from 0.2 to 0.5 mm. Stibnite is
characterized by being grey-white in colour, by strong anisotropism and high reflectiv-ity.
Stibnite crystals are usually surrounded and corroded by goethite. It is partially to
completely altered to secondary cervantite (Sb204) (Fig. 1). Occasionally, stibnite
contains minute inclusions of quartz, sphalerite, pyrite, chalcopyrite and tetrahedrite.
Cleavage planes and twinning are well developed (Fig. 2). The twin lamellae are of
deformational origin and are not growth lamellae, whereas the twin lamellae may show
displacement and translation twinning.
Fig. 2. SEM showing cleavage in the stibnite ( X 470).
5. L.H. Madkour, LA. Salem / Hydrometallurgy 43 (1996) 265-275
Table 1
Microprobe analyses of stibnite and tetrahedrite
269
Element Stibnite
1 2 3
Tetrahedfite
St 27.08 26.58 26.82 24.33
Sb 74.46 74.09 75.02 30.63
Fe 0.063 0.148 0.036 3.405
Cu 0.084 - 0.01 36.99
Zn - 0.013 - 3.412
Total 101.68 100.83 101.88 98.77
The antimony content of stibnite was determined by scanning electron microprobe
analysis (SEM) at the Camborne School of Mines, England. The data are given in Table
1. The Sb (average 74.52%) and S (average 26.83%) contents indicate that virtually all
the Sb is present as stibnite. Iron, copper and zinc contents are very low.
Tetrahedrite is rare, isotropic and forms minute rounded crystals of grey colour with a
brown tint disseminated in the stibnite. Microprobe data of the tetrahedrite are given in
Table 1. It is characterized by a high concentration of Fe (3.41%) and Zn (3.41%),
probably due to the substitution of Fe or Zn for Cu.
The paragenetic sequence began with crystallization of tetrahedrite, pyrite, chalcopy-rite
and sphalerite followed by stibnite. A period of oxidation conditions produced a
secondary antimony mineral (cervantite). Finally, goethite was formed, invading and
replacing the early mineralized vein lode.
Table 2 shows that the bulk sample of stibnite ore contains 65% Sb, 0.5% Fe, 2% As,
6.67% S and 18.74% SiO 2. The results of X-ray diffraction analysis of the sample are
shown in Fig. 3. The reflections of the stibnite sample were identical to those given by
ASTM card numbers 6.474 for stibnite; it can be seen that stibnite and quartz are the
o essentialo comp.onents in the sample. The most characteristic lines of stibnite are: 5.05 A,
3.56 A, 3.05 A 2.76 A and 2.52 A; whereas quartz was identified by its characteristics
lines at: 3.34 ,~, 4.24 ,~, 1.81 .~, 2.45 ,~, 2.28 ,~ and 1.54 ,~ (1 ,~ = 0.I nm).
Table 2
Chemical and spectral analysis of bulk sample of stibnite ore
Element Content Element Content Element Content
(%) (%) (%)
Sb 65 Mn 0.003 Ag 0.00001
Fe 0.5 Cr 0.005 Co 0.00(~5
Pb 0.05 Ni 0.0005 S total 6.67
Zn 0.03 B 0.001 SiO 2 18.74
As 2 Ti 0.0001 L.O.I. * 5.86
Cu 0.01 Sn 0.0001 Moisture 0.84
* Loss on ignition in weight percent at 1100°C.
6. 270 L.H. Madkour, I.A. Salem/Hydrometallurgy 43 (1996)265-275
Sti bnite
N
N N J~ .O
q~' m ill .D i~ N Ii~J j3 ..C)
m N O ~
m m
6B 60 50 40 30 20 14
Fig. 3. X-ray diffraction pattern for separated crystals of stibnite.
The infrared absorption spectrum of the sample of stibnite ore is represented
graphically in Fig. 4. Stibnite was detected by 2 moderate to weak absorption bands at
675 cm- ~ and 460 cm- ~. The band at about 1070 cm- ~ is characteristic of quartz.
3.2. Acid leaching treatment of sfibnite ore sample
3.2.1. Hydrochloric acid leaching
Stibnite dissolved very slowly and incompletely when boiled with concentrated
hydrochloric acid with the evolution of hydrogen sulphide, but decomposition with a
mixture of concentrated hydrochloric and tartaric acid has been recommended [15]. The
reaction is accompanied by intensive evolution of gases, so the oxidation was performed
in a conical flask or a high beaker, covered by a watch glass. Antimony ores are
decomposed easily by bromine solvents [16]. Whereas direct oxidation of sulphidic
Stibnite
I I I I 8100 I I I I I I
4000 3500 2S00 I 1400 1000 600
WAVENUMBE R ( C f61 )
Fig. 4. Infrared absorption spectrum for separated crystals of stibnite.
I
200
7. L.H. Madkour, LA. Salem / Hydrometallurgy 43 (1996) 265-275 271
sulphur to sulphate takes place at room temperature, the method is not used generally to
determine the main components, but it has been found useful for the determination of
trace elements.
3.2.2. Nitric acid leaching
Nitric acid, dilute as well as concentrated, is a powerful solvent for a number of
minerals, especially for sulphides [10,11]. The acid alone is used only in a limited
number of cases; mixtures with other mineral acids are more frequently used. Being a
strong oxidant, it oxidises sulphides to sulphates; antimony sulphosalts are converted to
the respective metal acids of the higher oxidation states, which are generally only poorly
soluble. Sulphur in sulphide ores must be oxidised at room temperature, with the dilute
acid only. The metal acids precipitated adsorb a large amount of foreign ions in an
acidic medium. Therefore, hydrolysis must be suppressed by adding other mineral acids
or complexing agents.
A mixture of nitric and tartaric acid [17] was used in the present work to decompose
the stibnite ore sample. This method was proposed by Hampe [18] and has found wide
application in the analysis of minerals containing antimony and tin, as well as of
metallurgical products. Thus, tartaric acid is used mainly for the analysis of antimony
ores. After dissolving the ore in concentrated acids, tartaric acid is added to the solution
before dilution with water, to avoid the hydrolysis of antimony; tartaric acid alone
dissolves some oxidized antimony minerals.
3.2.3. Sulphuric acid leaching
Concentrated H2SO 4 is an efficient solvent for the decomposition of sulphide and
oxide antimony ores [19] and gives good recovery when used alone or, more frequently,
in mixtures with other solvents.
Hot concentrated H2SO 4 was employed here for the decomposition of the stibnite ore
sample in the presence of small amounts of tartaric acid. Antimony and arsenic were
easily precipitated from sulphate solution as sulphides, in a form easy to filter. Boiling
with concentrated H2SO 4 at the same time also causes complete dehydration of silicic
acid, which is thus converted to a suitable form for quantitative precipitation. Any
antimony trisulphate Sb2(SO4) 3 formed decomposes in water. The efficiency of the
various reagents for leaching and treatment of the stibnite ore are compared in Table 3.
3.3. Electrodeposition of antimony
The effects of concentration of antimony ions in the leach liquor, the nature of the
complexing agents, the current density, temperature and the presence of other impurities
were studied. The optimum conditions for the electrodeposition of metallic antimony
from its mother liquor and the various electrolyte solutions are summarized in Table 3.
Characterization of the solid complexes was investigated using elemental analysis,
conductance, magnetic susceptibility and spectroscopic methods. For each experiment,
the results of chemical and spectrophotometric analyses indicate that the purity of the
electrodeposited metal was 99%.
9. L.H. Madkour, 1.4. Salem/Hydrometallurgy 43 (1996)265-275 273
Effect of the concentration of Sb ions: Silvery white, adherent deposition was found
to take place in the concentration range >_ 0.05 M. At very low concentrations of
antimony ions in electrolyte solution (< 0.05 M solution) no deposition takes place,
owing to the very small concentration of ions in solution. The results show that there is a
critical concentration at which one obtains the maximum rate of deposition.
Effect of complexing agents: Cathodic deposition takes place in the absence of
complexing agents, so the effect of the complexing agent [20] in rendering differences
between the reversible potential of antimony and its standard potential is important.
Table 3 shows the existence of the antimony complex species prepared from the leach
liquor chloride. These complex species in solution have recently been identified by
conductometric titrations using 0.001 M antimonyl chloride with 0.01 M complexing
solution. The measured conductance of the solution was plotted against the volume of
complexing agent (NaF, NaNO 3, CH3COONa, C6HsO7Na 3, C4HsO4Na or NH4C1)
added. The conductance curves showed breaks at certain molar metal/complexing
agents ratios, corresponding to the formation of 2:1 antimony complexes with all ligands
used. Experiments using an ion-exchange resin technique [21,22] confirmed the presence
of positively charged complex species. The formation of the cationic complexes
indicated above has previously been reported [8]. Furthermore, complexing agents have
an important role in ensuring the presence of a sufficiently small SbO ÷ ion concentra-tion
at the cathode, suitable for the reduction and the smooth deposition of the metal.
Table 3 shows the most suitable concentrations of Sb ions and complexing agent
required in order to reach high current efficiency.
Effect of temperature: Increasing the temperature of the solution from 25°C to 60°C
favours the cathodic deposition of the metal. This is due to the improved mass transport
[23] of complex species towards the platinum cathode.
Effect of current density: At low current density (less than 100 A/m 2) only a thin
layer of antimony was deposited, owing to the low rate of cathodic reactions occurring
at the cathode. At higher current density (> 1000 A/m 2) the deposit formed was not
adherent. This is attributed to the rapid discharge of hydrogen ion.
Current efficiency: The decrease in the cathodic current efficiency (Q%) is related to
several factors, including a decrease in hydrogen overvoltage on certain areas of the
antimony electrodeposition [24], or an increase in the evolution of hydrogen; the
presence of other metal cations during the deposition process and the possible alteration
in the growth morphology of the antimony deposited by impurities originally present in
the leach liquor. The lower current efficiency values are attributed to the platinum plate
used as the cathode and the dilute solution of antimony [25] in the electrolyte.
3.4. Kinetics and mechanism
The rate of deposition (using electrolyses with controlled electric potential) increases
slowly at first and then increases sharply to attain a maximum value at 40 rain and then
decreases sharply. This may be attributed to the lower concentration of metal ion around
the cathode and the rapid formation of Sb powder in the bottom of the cathode
compartment. The cathodic deposition of antimony proceeds at first by the formation of
the corresponding complex species, followed by migration of the complex species
towards the platinum cathode and, finally, deposition of the antimony.
10. 274 L.H. Madkour, I.A. Salem/Hydrometallurgy 43 (1996)265-275
3.5. Recommended flowsheet
The various steps required for the hydro- and electrometallurgical treatment of
stibnite ore are summarized in the proposed flowsheet in Fig. 5. Three alternative
pathways have been attempted successfully. Metallic antimony was deposited cathodi-cally
from the leach liquor after leaching processes to various antimony salts (nitrate,
sulphate and chloride). Antimony chloride with water forms antimony oxychloride
(SbOCI). The hydrated antimony salts obtained as an end product of the leaching
process have many industrial applications in the manufacture of bronzing iron, mordant,
manufacturing lakes, matches, pyrotechnics, pharmaceuticals, flameproofing textiles and
in the electrowinning of antimony metal. In the case of the leach liquor chloride,
antimony metal was cathodically electrodeposited either directly from the liquor or in
the presence of a complexing agent (NaF, CH3COONa or NH4CI) with constant stirring.
1-12SO acid leaching I
Stibnite ore
HC1 acid leaching I
Leach4__~ ~ residue I'-
Washing and mtration I
I "-I~I Leach liquor I
I
+ CoaL geln ext ing Di*rec t
Antimony electrolysis I
Antimony metal product
Fig. 5. Flowsheet for antimony electrometallurgy.
HNO acid leachin~
11. L.H. Madkour, LA. Salem/Hydrometallurgy 43 (1996)265-275 275
It can be noticed that the reagents used either in the leaching treatment or in the
electrolysis process, such as hydrochloric acid, nitric acid, sulphuric acid and tartaric
acid, are relatively cheap and common reagents. The advantages of this flowsheet are
concerned also with the low temperature used for both the leaching and electrodeposi-tion
processes and, hence, the low energy consumption.
References
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