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The startup operations of continuous casting sequences of steel in a 4-strand tundish, using three different turbulence inhibitors (TI), were investigated using a 1/3-scale water model in combination with numerical simulations through the volume of fluid model. The two-phase flow water–air is used to model the system, and the liquid steel–air and the liquid–gas interfaces are tracked by a donor–acceptor...
Water pollution, including the generation of wastewater, is becoming an increasingly serious global issue. In this study, ilmenite (FeTiO3) nano-photocatalysts were synthesized via a simple sol-gel method to determine their applicability to wastewater remediation. Methylene blue was photocatalytically decomposed by visible light in the presence of nano-ilmenite, and batch experiments were performed...
Leaching dephosphorization is an effective way to remove the harmful element phosphorus from steel slags. In order to recycle the leach liquor, static phosphate adsorption with activated aluminum oxides was investigated in this work. It was demonstrated that, for an initial phosphorus concentration of 25.95 mg/L, a phosphorus removal rate of 88% and an adsorption capacity of 0.72 mg/g can be reached...
We describe the use of sulfiding agents to achieve a significant increase in the level of metal recovery during the smelting of copper concentrates and matte conversion. In the conversion process for copper and polymetallic mattes, the addition of sulfides produces (1) a remarkably low level of nonferrous metals remaining in converter slag; (2) a high level of copper extraction to matte; (3) high...
Hydrophobic palladium-capped vertically aligned porous titanium nanoflake (Pd/Ti) thin film has been grown on a Si substrate by DC-sputtering. The hydrogenation (0.5 bar) and dehydrogenation (100°C) kinetics of the Pd/Ti thin film have been studied in terms of their structural, morphological and optical properties. X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and UV–Vis–NIR...
Due to stringent environmental requirements and the complex occurrence of valuable metals, traditional pyrometallurgical methods are unsuitable for treating low-grade nickel-copper matte. A clean and sustainable two-stage sulfating roasting and water-leaching process was used to simultaneously extract valuable metals from low-grade nickel-copper matte. Ammonium and sodium sulfate were used as sulfating...
Fluorides are widely used to improve vanadium extraction from shale in China. Sulfuric acid baking–leaching (SABL) was investigated as a means of recovering vanadium which does not require the use of fluorides and avoids the productions of harmful fluoride-containing wastewater. Various effective factors were systematically studied and the experimental results showed that 90.1% vanadium could be leached...
In the vanadium metallurgical industry, massive amounts of ammonia hydroxide or ammonia salt are added during the precipitation process to obtain V2O5; therefore, wastewater containing a high level of NH4+ is generated, which poses a serious threat to environmental and hydrologic safety. In this article, a novel process was developed to recycle ammonia wastewater based on a combination of ammonia...
W6Mo5Cr4V2Co5Nb (825 K) alloy was prepared by a two-step sintering process from overspray 825 K alloy powder. The overspray powder characteristics and the microstructure and mechanical properties of the as-sintered 825 K alloy were investigated. Results showed that two types of carbides formed a network structure in the overspray powder, which had spherical or quasispherical shape: one was MC carbide...
Acid-leaching behaviors of the titanium slag obtained by selective reduction of vanadium-bearing titanomagnetite concentrates were investigated. It was found that the optimal leaching of titanium and silicon were 0.7% and 1.5%, respectively. The titanium and silicon in the titanium slag were firstly dissolved in the acidic solution to form TiO2+ and silica sol, and then rapidly reprecipitated, forming...
An H13 (high-strength, low-ductility) tool steel die will fail due to compressive high cycle fatigue. If the die is manufactured by direct metal deposition and layered with Inconel-718 (low-strength, high-ductility), it may impact the mechanical properties of the material. Hardness tests, micro-tensile tests, and micro-compression tests were used to analyze the mechanical properties of this additive...
The concepts of oxide metallurgy and inclusion engineering can be utilized to improve the properties of low-alloy steels. These concepts aim at controlling the formation of intragranular ferrite (IGF), often a desirable microstructure providing good mechanical properties without the need for expensive alloying elements. IGF formation is stimulated to occur at non-metallic inclusions and form an arrangement...
The bottom-blown copper smelting furnace is a novel copper smelter developed in recent years. Many advantages of this furnace have been found, related to bath mixing behavior under its specific gas injection scheme. This study aims to use an oil–water double-phased laboratory-scale model to investigate the impact of industry-adjustable variables on bath mixing time, including lower layer thickness,...
Most modern Additive Manufacturing (AM) processes were invented and commercialized in a short period of time spanning 1984–2000. This paper reports on AM processes invented in the 1974–1987 time period, known as precursor AM processes. The critical difference between the two periods is public knowledge and utilization of distributed computing.
A series of polysulfone membranes with different porous structures were prepared via phase inversion method. These membranes were examined by electrochemical impedance spectroscopy (EIS), the positron annihilation technique, and water flux measurement. EIS and water flux results confirmed that the membranes exhibited more tunnels for the permeation of ions or water molecules with increasing polyethylene...
A filter-based Euler–Lagrange multiphase flow model is used to study the mixing behavior in a combined blowing steelmaking converter. The Euler-based volume of fluid approach is employed to simulate the top blowing, while the Lagrange-based discrete phase model that embeds the local volume change of rising bubbles for the bottom blowing. A filter-based turbulence method based on the local meshing...
The grain growth kinetics of 8YSZ ceramics processed using spark plasma sintering (SPS) has been investigated in the temperature ranging from 1100°C to 1500°C. The activation energy during SPS densification was obtained as 332 kJ/mol with grain boundary diffusion as a dominant mechanism. Further, the effect of CeO2 on the densification kinetics of 8YSZ ceramic processed via SPS and conventional sintering...
In the continuous casting of steel, argon gas injection through the upper tundish nozzle wall or stopper tip is known to decrease clogging and remove inclusions. In addition to this intended gas injection, gas may be passively aspirated into the flow system by negative pressure developed inside of the nozzle. The injected gas forms gas pockets and bubbles through complex redistribution processes that...
Kinnor Chattopadhyay is the JOM advisor for the Process Technology and Modeling Committee – part of the TMS Extraction & Processing Division and the Materials Processing & Manufacturing Division – and guest editor for the topic Multiphase Flows in Materials Processing: Part I in this issue.
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