This communication summarises the known thermodynamic properties of impurities in liquid silicon. This information may be used to evaluate different refining processes. Example calculations are presented. The known free energy of solution and Henrian activity coefficients are provided for impurity elements dissolved in nearly pure silicon. Distribution coefficients are also given.

The effect of high-pressure grinding roll (HPGR) comminution on the physical properties of ore particles and heap leaching of gold was investigated compared with that of conventional jaw crusher comminution. The comminuted products were evaluated in terms of particle size distribution, internal crack density, and saturated water content. Compared to conventional jaw crushers, the HPGR produced finer

The content of metallic impurities was studied in the fine particles of gold ore recovered from various types of deposits. Experimental data showed that the gold content in the particles with diameter D < 2 μm decreases alongside with the decrease of particles sizes. This dependence is explained by the increased thermodynamic activity of the gold dispersion and amorphisation in the linear dimensions

A vertical tubular reactor is used for the oxidative leaching process in the mineral processing industry, especially sphalerite. Oxygen could oxidise ferrous ions (Fe2+), and ferric ions (Fe3+) are generated as the principal oxidation agent in the reactor afterward. The partial pressure of oxygen is an instrumental parameter that could change according to reactor height. Despite the extensive studies

The oxygen pressure leaching of sphalerite in sulphuric acid solutions is a slow process in the absence of iron because of the limitations of the oxygen delivery carrier (redox couple: Fe3+/Fe2+). Herein, the artificial sphalerite with 25.70%, 15.20%, 5.75% iron contents and non-iron was prepared via the sintering of ZnS and FeS and used in the kinetic oxygen pressure leaching experiment. The results

Cupric chloride leaching is an attractive alternative for the treatment of pyritic refractory gold ores. In this context, the kinetics of pyrite dissolution was studied in cupric chloride solutions containing 4 M NaCl. Pyrite leaching experiments were conducted in a stirred tank reactor for 250 h. The effect of temperature was evaluated at 45°C, 60°C and 75°C, while the effect of [Cu (II)] was evaluated

The effects of leaching parameters on the metal dissolutions from Caldag laterite ore using hydrochloric acid at atmospheric pressure were investigated. The following leaching parameters were examined to understand their effects on the dissolution of the metals: hydrochloric acid concentration, solid/liquid ratio, particle size, leaching temperature and time. Extractions of 95.8%Ni, 94.5%Co and 94

In this work, the effects of the dynamic precipitation on the mechanical properties of Al 2024 alloy were investigated under as-received (AR), solution heat treated (SHT), peak aged (PA) and over aged (OA) conditions. The cold, warm and hot deformation were carried out at 25°C, 150°C, 250°C and 350°C for the strain rate of 5.55 × 10−4 s−1. The results indicated that dynamic precipitation takes place

A cyclic DSC method has been adapted to study the TLPB behaviour and isothermal solidification rate (IS) in an IN625/CPW475 base metal/filler metal joint at 1000°C. Analysis of the DSC data resulted in a prediction of the maximum brazing clearance (MBC) as a function of braze time. The rate of IS was determined to be linear with the square root of time with a rate constant k = 4.59 µm/min1/2, once

Failure analysis is a key concern in the development of composites. It not only helps to understand the material performance under severe loading conditions but also to decide the suitability of the material in particular applications. In this context, this paper highlights the behaviour of AZ91E with 2 wt-% nickel-coated alumina reinforced composites under different loading conditions. Composites

The effect of chloride exposure on copper cooling element corrosion was investigated in a simulated flash smelting furnace atmosphere. Field samples exposed to low and high chloride loads were first characterized with a scanning electron microscope. The main difference between the samples was the presence of a separate copper chloride layer in the samples that had been exposed to high chloride loads

Vortexing in continuous slab casting can entrain mould powder and thus damage the slab quality. In this investigation, a 0.4-scale water caster has been employed to explore the interaction between air and vortices. Black sesame seeds are injected into the water to get the better visualisation of air-vortex interaction. Momentum exchange between ascending air bubbles and vortexing has caused variations

In this research, the role of Si on the solidification behaviour of NiAl cladding produced by the GTAW process was studied. NiAl and Ni2AlSi compounds were synthesised by mechanical alloying. The produced powders were cladded on the surface of CK45 steel using the GTAW process. Phase evolutions, microstructural changes and fractography of the produced powders as well as the cladded layers were characterised

Particle size and shape of iron ore concentrate are effective parameters in the production of quality green pellets. In this research, the effect of particle morphology on green pellet quality was studied. It was concluded that pellet quality improved with increasing specific surface area. Drop number and green compression strength of pellets ground by HPGR were found to be superior over those ground

A mathematical model has been developed by coupling genetic algorithm (GA) with heat and material balance equations to estimate rate parameters and solid-phase evolution related to the reduction of iron ore-coal composite pellets in a multi-layer bed Rotary hearth Furnace (RHF). The present process involves treating iron ore-coal composite pellets in a crucible over the hearth in RHF. The various solid

The microstructure evolution for different post-homogenisation cooling rates and the flow stress behaviour in direct chill cast AA6060 alloys were studied. Results revealed that decreasing cooling rates reduced the flow stress owing to the precipitation of Mg2Si and reduction of the solid solution level. Micro-alloying of Mn generated a distribution of α-Al(FeMn)Si dispersoids during the homogenisation

Vortices at the meniscus of the continuous casting mould can entrain mould powder into the liquid pool. The entrained globules will form slivers in the subsequent downstream processing of the slabs. This article presents a three-dimensional computational study of the vortexing at the meniscus with an emphasis on capturing flow behaviours of vortices in continuous casting mould. We have used ANSYS FLUENT

This paper describes a detailed study of the segregation process in which nickel, cobalt and iron were extracted as volatile metal chlorides from a nontronite laterite, and concentrated as alloy onto carbon within a single step. Topics covered include: metal recovery, ferronickel grade, extraction kinetics, gaseous reduction of iron oxides, evolved gas volume and composition, carbon utilisation and

The character and cause of sliver defect on IF steel sheet surface are studied by means of SEM, unstable flow in mould could induce surface velocity and level fluctuations, leading to surface defects during continuous casting of steel. The nozzle clogging is a serious problem during the continuous casting of steel, due to its influence on the casting operations and products quality. In this study,

To promote biooxidation efficiency of a refractory high-sulphide gold concentrate, microwave technology has been applied. Two factors were investigated in the microwave stage including initial solution pH and microwave irradiation time. The results show that biooxidation efficiency of the gold concentrate increases with the increasing initial solution pH. The effect of microwave irradiation on biooxidation

This study evaluates iron recovery from low grade banded hematite quartzite iron ore. The ore was found susceptible to microwaves and hence carbothermal reduction was pursued. The susceptibility of iron phases to microwave exposure and their selective absorption assists in the liberation of iron values. It was observed that ferrite balls were formed when a small fraction of ore-charcoal mixture was

During the extraction of magnesium by the electrothermal process, the condensation of magnesium vapours in the condenser is critical to achieve operational efficiency. In the present work, a mathematical heat transfer model has been developed to predict the growth rate of a single liquid metal drop during dropwise condensation (DWC) of magnesium vapours in the electrothermal process. Homogeneous DWC

Argon gas is often injected from the bottom of the ladle during steel refining operations. The injected gas interacts with the liquid (metal and slag) bath and enhances the momentum, heat, and mass transfer rate in the melt. However, during these gas–liquid interactions, an opening of the slag layer called slag eye is formed, which exposes the molten metal surface to the atmosphere, which is generally

The foaming behaviour originating from the reduction of iron oxide in molten CaO–SiO2–MgO–Al2O3–TiO2 slag was studied at 1500°C with the aid of a real-time foaming process monitoring system. The effect of TiO2 content and binary basicity on the slag foaming were investigated. It was found that the TiO2 content has a significant influence on the foaming degree, while the basicity of the slag has a smaller

The recycling application of bauxite residual is limited by its high content of iron, unfortunately, the complicated embedding feature of haematite makes it quite difficult to be removed efficiently and cleanly. In this paper, the process of selective reducing-magnetic separation without acid leaching is adopted to remove iron from bauxite residual. Different parameters such as carbon mass addition

This paper investigates the distribution of harmful elements in furnace burden and refractory of a water-quenched blast furnace X (BFX) through SEM images, EDS spectra and XRD results. The results show that zinc is mainly concentrated on the lumpy zone while the dominant enrichment region of alkali metal is the cohesive zone. The microstructure and XRD results of refractories in various locations indicate

The non-isothermal reduction kinetics and volatilisation behaviour of iron (Fe), silicon (Si), and magnesium (Mg) during the vacuum carbothermal reduction of ilmenite concentrate were investigated from 1350°C to 1550°C. Mg species was reduced to metallic Mg before volatilisation. Some Si elements were reduced to Si, which entered into the Fe phase to form ferrosilicon alloy, and others were reduced

In the present study, laboratory-scale experiments and thermodynamic calculation between the mould slags and the steel were performed to investigate reaction performances of mould slags during continuous casting (CC) of 321 stainless steel. The results show that in the final Slag1 (traditional mould slag), SiO2 decreased by 3.86 wt-% and TiO2 increased by 4.85 wt-%, whereas the melting temperature

In continuous casting, molten steel often contains non-metallic inclusions that have a very high melting temperature and thus remain suspended in the molten flow. Given the lower density of these substances compared to the melt, they can be filtered in the form of top slag by proper use of buoyancy forces. Thus, providing a desirable flow pattern, reduced flow turbulence, and adequate residence time

This paper describes the development of a flowsheet using a combination of sample preparation, magnetic separation (in a range 0.4–1 T), microwave treatment (in a range 0.54–0.9 kW), and leaching operations (HCl, in a range 0.25–1.25 M) for the beneficiation of iron ores (Total Fe [TFE]: 55.48%). The work was aimed at recovering TFE from the non-magnetic product by increasing its magnetic susceptibility

Some materials when exposed to various conditions can exhibit a rise in temperature without requiring an external heat source. Generally referred to as pyrophoric or self-heating substances, they challenge the safety of materials handling, storage and transportation. Reliably assessing the self-heating potential of materials is thus essential. Over the years several test protocols have been developed

The purpose of this study was to investigate the role of grinding media type, water chemistry and pyrite mineralogy on the galvanic interaction between grinding media and pyrite during grinding of a gold ore. The galvanic current between pyrite and grinding media increased with the electrochemical activity of the grinding media, while it decreased as a function of increasing chromium content in the

In this study, the as-cast commercially pure aluminum 1A85 was prepared through continuous variable cross-section recycled extrusion (CVCE) technique at room temperature(300 K) to investigate the effect of number of CVCE passes on its microstructure and mechanical properties. The results showed that the ultrafine-grained pure Al with the average grain size of 0.4 μm could be obtained after 3 passes

The operation of blast furnace is considerably influenced by slag performance, particularly in BF hearth. Slag holdup in deadman has negative effects on hearth, such as sharp peripheral flow of hot metal and carbon brick erosion. Therefore, it is urgent to monitor the slag holdup. In this paper, a slag holdup model was proposed to give a transient snapshot of the internal state of BF. Based on the

Ca treatment is generally used in the production of Al-deoxidised steel to prevent nozzle blockage by modifying high melting point inclusions such as MgO·Al2O3 (Melting point: 2408 K). However, the successful application of Ca treatment can be quite difficult due to the requirements for stringent control of the amount of calcium that is added. In the present paper, a novel and effective method of inclusion

The need for fast mean field models describing phase transformations in varying temperatures was the motivation for the research. The aim was to propose an austenite-ferrite transformation model which can be successfully substituted for the JMAK model and eliminate its weak points. The model consists of a second order differential equation which describes the kinetics of both the austenite-ferrite

The amount of discarded plastic-containing materials is increasing, and one option to help with this issue is to use these materials in bath smelting processes. The injection of plastic-containing materials to partially substitute coal in zinc-fuming processes has been studied in an industrial trial at Boliden–Rönnskär smelter. To evaluate the potential of plastic-containing materials, thermodynamic

Copper sulfides mostly occur in minerals such as chalcopyrite, chalcocite, and bornite. Copper extraction requires liberation of these minerals from the host rock by fine grinding, during which rapid oxidation could alter their surface characteristics, thereby affecting their flotation behaviour. The −20 + 10 mm fraction pebbles are compared with steel balls as media for grinding of a copper concentrate

15-5PH steel is one of the martensitic precipitation-hardened stainless steels, which is extensively applied in the aero shafts, and electron beam welding is a significant procedure to manufacture the parts. To verify the dimension accuracies and properties, EBW with oscillation was employed on the cylinders of 15-5PH steel. The welding distortions were measured, and the microstructures and tensile

The electrochemical behaviour of the Pb-0.7% Ag anode has been investigated in zinc sulphuric acid electrolyte containing 5, 8, 12 g/L Mn2+ by electrochemical measurements at different temperatures of 35°C, 40°C, 45°C. It was observed by cyclic voltammetry before electrolysis that temperature increase from 35°C to 45°C resulted in a decrease in the oxidation peak I (Pb → PbSO4) and an increase in the

Shredder residue materials are produced after the removal of ferrous and non-ferrous fractions from end-of-life electronic equipment. Despite the high plastic content and metal value in the ash, high percentages of these materials are currently sent to landfills. In this study, the potential of utilising shredder residue material and other plastic-containing materials as reducing agents was studied

In continuous slab casting, clogging in the submerged entry nozzle (SEN) ports leads to flow asymmetry and vortex formation in the mould. Knowledge of vortexing and its influence on product quality is fundamental for defect-free production. In this study, the interconnected effects of nozzle clogging and SEN submergence depth, variation on flow asymmetry and vortex characteristics in a 0.4 scale water

In this study, corrosion behaviour of double-phase Al1.3CrFeNi chemically complex alloy was investigated, including hot corrosion and electrochemical corrosion. Hot corrosion behaviour of Al1.3CrFeNi alloy was explored in molten 75 wt-% Na2SO4 + 25 wt-% NaCl salt. The result revealed that the corrosion kinetic curve of Al1.3CrFeNi alloy followed the exponential rate rule through mass loss measurement

The kinetics of Cr (VI) reduction by grey cast iron powder (HT250 as per Chinese standard GBT 9439-2010) was investigated in this paper. Factors such as pH, initial Cr (VI) concentration, particle size, stirring speed and temperature on Cr (VI) reduction were first examined at a moderate reducing agent dosage. It was found that Cr (VI) reduction could only occur at an initial pH of 2.0 and above this

In the present study, isothermal reduction kinetics of titaniferous magnetite ore (TMO) fines (below 75 µm particle size) using coke dust, an industrial waste, in the form of briquettes have been performed at temperatures ranging from 1273 to 1473 K over varying reduction times: 5, 10, 20, 30, 40 & 60 min. This process aims at the efficient utilisation of TMO which can serve as an alternate potential

The top-blowing supersonic oxygen jet is now used widely in steelmaking and metal refining processes. However, the ambient temperature and oxygen flow rate is changed during top-blowing process, making the flow field of supersonic oxygen jet unstable. Hence, it is very important to research the behaviour of supersonic oxygen jet in high ambient temperature. In the present study, the supersonic coherent

Polystyrene beads were coated with activated carbon under hydrothermal conditions above the glass transition temperature of polystyrene. By precisely controlling the temperature between 140 and 145 °C under vigorous mixing conditions in the presence of an excess of activated carbon, the surface of polystyrene beads were made sufficiently tacky so that finely sized activated carbon particles adhered

Enhanced gravity concentrators such as Knelson concentrator (KC) are extensively used in the mineral processing industry. The complexities of KC bowl geometry and variation of feed characteristics have forced process engineers to design empirically new units using laboratory and pilot-scale Knelson concentrators. However, numerical modelling methods such as computational fluid dynamics (CFD) and discrete

The presence of impurities in the copper electrolyte increases the energy consumption of an electrorefining process and contaminates the deposited copper on cathode. The concentration of impurities increases over time making it necessary to remove them from the solution. This research introduces a fast, effective, and simple method to refine the industrial electrolyte from arsenic, iron and antimony

Slag that is produced from induction furnaces that use the Merrill–Crowe process still contains precious metals. In this study, a pyrometallurgical treatment was performed for their recovery in order to realise economic savings and reduce environmental concerns. An analysis was performed to determine the effect of two fluxes (sodium carbonate and anhydrous borax) on the recovery of silver at different

Calcium metal was successfully produced from Egyptian limestone ore under vacuum using aluminium as a reducing agent. The aluminothermic reduction process of CaO by aluminium metal was followed up by collected amounts of produced calcium metal. The progress of the reduction process was investigated by the phase analysis of produced reaction residues through X-ray diffraction. The technical parameters

Optimisation studies on integrating different procedures in mining and mineral processing have an increasing popularity in recent years, and most of them focus on the mine-mill or mine-flotation integration. However, few optimisation studies on integrating mining with gravity separation are found. The gravity separation plays a vital role in coal preparation, which also makes the related integration

The reduction of chromium-bearing vanadium–titanium magnetite sinter (CVTMS) by CO was investigated at 1123–1223 K. The reduction degree increased with increasing temperature. The isothermal reduction kinetics of CVTMS was analysed, according to Sharp analysis and ln–ln analysis, the kinetic mechanism of reduction process for all samples in different basicity can be represented as f(α) = 1.61(1−α)[−ln(1−α)]1–1/1

In the present investigation, the effects of alloying elements (Sn, Pb) and grain refiner (Ag, Zr) on microstructure, mechanical and wear properties of as-cast Mg-Al-Zn alloys were studied. The alloys were prepared through melting-casting route under a protective atmosphere and cast into a permanent mould. The microstructure of the base alloy consisted of α-Mg, Mg17Al12 continuous eutectic phase at

In copper smelting process, oxygen-enriched smelting leads to the enrichment of magnetite and increase of slag viscosity, which is not conducive to the sedimentation and separation of copper. Therefore, it is necessary to reduce magnetite in order to improve the recovery rate of copper. In this work, biodiesel produced from waste cooking oil was used to replace carbon and diesel, which should be more

A route of vacuum carbothermal reduction of Panzhihua ilmenite was introduced to prepare Ti-rich material. The effects of mass ratio of graphite to ilmenite, reduction temperature and vacuum condition on compositions of products and contents of impurities were investigated. Scanning electron microscope images showed that Mg mainly existed in MgSiO3, MgAl2O4 and MgnTi3−nO5 in ilmenite. Thermodynamic

This study examines the extraction of beryllium and aluminium from a Nigerian beryl ore using Cyanex®272 in kerosene from an aqueous sulphate pregnant solution. Parameters such as extractant concentration and equilibrium pH that dictates the extraction yield were studied. Under the following conditions: temperature 27 ± 2°C, phase ratio 1׃1, about 45.50 and 46.76% of beryllium and aluminium were extracted

Styryl phosphoric acid (SPA) is considered to be one of the best selective collectors for rutile flotation. Yet high consumption and considerable environmental pressure have limited its wide applications. In this study, n-nonyl alcohol (NNA) was used as the auxiliary collector to reduce SPA dosage. The experimental results indicated that when SPA was used as the single collector, the rutile flotation

The effects of various activators on the flotation behaviour of lime-depressed pyrrhotite (FeS1.1) were investigated. The activation mechanisms were studied using electrochemical analysis, Fourier transform infrared spectroscopy, zeta potential measurements, and X-ray photoelectron spectroscopy. Micro-flotation results showed that the floatability of pyrrhotite declined sharply from 97.6% to 5.1% with

The separation of zinc and iron is essential in hydrometallurgical processes, especially for treating high-iron sphalerite. The hematite precipitation process for removing iron is an effective way to achieve the high-efficiency separation of zinc and iron. The authors studied the effect of temperature and time on the precipitation behaviour and characterised the precipitation products through X-ray