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Metals
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Metal Recovery and Separation from Wastes
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Metal Recovery and Separation from Wastes

A special issue of Metals (ISSN 2075-4701). This special issue belongs to the section "Extractive Metallurgy".

Deadline for manuscript submissions: closed (20 January 2023) | Viewed by 31708

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special Issue Editors

Prof. Dr. Lijun Wang

E-Mail Website
Guest Editor
Collaborative Innovation Center of Steel Technology, University of Science and Technology Beijing, Beijing 100083, China
Interests: physical chemistry; refining process; recovery valuable elements from metallurgical waste; molten slag; slag structure; AIMD simulations
Dr. Shiyuan Liu

E-Mail Website
Guest Editor Assistant
Collaborative Innovation Center of Steel Technology, University of Science and Technology Beijing, Beijing, China
Interests: recovery of valuable elements from metallurgical waste; molten slag; vanadium flow battery; MOF

Special Issue Information

Dear Colleagues,

With the development of society, large amounts of solid waste (slag, sludge, tailing, electronic waste, etc.) are generated every year. Each type of waste contains specific metals, such as As, Cr, V, Cu, Pb, and Zn, which are valuable resources and are also harmful to the environment. Currently, problems regarding the environment have increasingly attracted great attention as the global interest in these issues increases. If metals in wastes are not recovered effectively, not only will this waste resources but it will also seriously pollute the environment.

The current processes for recovering metals (V, Cr, Ti, Fe, Mn, Pb, Zn, Cu, Ni, Co, Al, As, Nb, Mg, Au, etc.) from wastes (slag, sludge, tailing, electronic waste, etc.) include gravimetric, magnetic, floatation, pyrometallurgical, hydrometallurgical, bioleaching, chlorination, and electrolysis methods, etc.

To minimize production costs and environmental impacts, it will be more and more necessary to use cleaner and more economical methods to recover metals from wastes. The purpose of this Special Issue is to focus on the current state-of-the-art ideas, methods, technologies, etc., for utilizing waste.

I gladly invite you to submit your work to this Special Issue.

Prof. Dr. Lijun Wang
Dr. Shiyuan Liu
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Metals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • gravimetric
  • magnetic
  • floatation
  • pyrometallurgy
  • hydrometallurgy
  • bioleaching
  • chlorination
  • electrolysis

Published Papers (15 papers)

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Editorial

Jump to: Research, Review

3 pages, 163 KiB  
Editorial
Metal Recovery and Separation from Wastes
by Lijun Wang and Shiyuan Liu
Metals 2023, 13(8), 1411; https://doi.org/10.3390/met13081411 - 07 Aug 2023
Viewed by 750
Abstract
With the development of society, large amounts of solid waste (slag, sludge, tailing, electronic waste, etc [...] Full article
(This article belongs to the Special Issue Metal Recovery and Separation from Wastes)

Research

Jump to: Editorial, Review

16 pages, 6607 KiB  
Article
Efficient Recovery of Cu from Wasted CPU Sockets by Slurry Electrolysis
by Wenjing Chen, Manning Li and Jiancheng Tang
Metals 2023, 13(4), 643; https://doi.org/10.3390/met13040643 - 23 Mar 2023
Cited by 1 | Viewed by 1201
Abstract
In order to maximize the reuse of used electronic component resources, while reducing environmental pollution, Cu metal was recycled from wasted CPU sockets by the reformative slurry electrolysis method. However, the influences on the regulation of the Cu recovery rate and purity from [...] Read more.
In order to maximize the reuse of used electronic component resources, while reducing environmental pollution, Cu metal was recycled from wasted CPU sockets by the reformative slurry electrolysis method. However, the influences on the regulation of the Cu recovery rate and purity from waste CPU slots, by slurry electrolysis, has not been systematically elucidated in previous studies. In this work, the effects of H2SO4 concentration, slurry density, NH4Cl concentration, current density, and reaction time, on the recovery rate and purity of Cu in slurry electrolysis, were researched by systematic experimental methods. The results showed that the recycled metal elements were mainly present as powders from the cathode, rather than in the electrolyte. Moreover, the metallic elements in the cathode powder consisted of mostly Cu and small amounts of Sn and Ni. The recovery rate and purity of Cu were up to 96.19% and 93.72%, respectively, with the optimum conditions being: an H2SO4 concentration of 2 mol/L, slurry density of 30 g/L, NH4Cl concentration of 90 g/L, current density of 80 mA/cm2, and reaction time of 7 h. Compared with previous studies, the Cu recovered in this experiment was present in the cathode powder, which was more convenient for the subsequent processing. Meanwhile, the recovery rate of Cu was effectively improved. This is an important guideline for the subsequent application of slurry electrolysis for Cu recovery. Full article
(This article belongs to the Special Issue Metal Recovery and Separation from Wastes)
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14 pages, 6572 KiB  
Article
Mechanism of Selective Chlorination of Fe from Fe2SiO4 and FeV2O4 Based on Density Functional Theory
by Junyan Du, Yiyu Xiao, Shiyuan Liu, Lijun Wang and Kuo-Chih Chou
Metals 2023, 13(1), 139; https://doi.org/10.3390/met13010139 - 10 Jan 2023
Cited by 1 | Viewed by 1304
Abstract
Vanadium slag is an important resource containing valuable elements such as Fe, V, Ti, and so on. A novel selective chlorination method for extracting these valuable elements from vanadium slag has been proposed recently. The proposed methods could recover valuable elements with a [...] Read more.
Vanadium slag is an important resource containing valuable elements such as Fe, V, Ti, and so on. A novel selective chlorination method for extracting these valuable elements from vanadium slag has been proposed recently. The proposed methods could recover valuable elements with a high recovery ratio and less of an environmental burden, while the study on the chlorination mechanism at the atom level was still insufficient. Fe2SiO4 and FeV2O4 are the two main phases of vanadium slag, and the iron element can be selectively extracted via the chlorination of NH4Cl. The NH4Cl decomposes into NH3 gas and HCl gas, which was the true chlorination agent. As a result, the chlorination reactions of Fe2SiO4 and FeV2O4 with HCl were firstly calculated using FactSage 8.0. Then, this paper studied the characteristics of HCl adsorption on the Fe2SiO4(010) surface and the FeV2O4(001) Fe-terminated surface mechanism of the selective chlorination of Fe from Fe2SiO4 and FeV2O4 via DFT calculations. The processes of chlorination of Fe2SiO4 and FeV2O4 involved the processes of removing O atoms from them with HCl gas. The iron in Fe2SiO4 was selectively chlorinated because HCl could adsorb on the iron site but could not adsorb on the silicon site. The iron in FeV2O4 was selectively chlorinated because the electronegativity gap between V and O was more significant than that between the Fe and O elements. Full article
(This article belongs to the Special Issue Metal Recovery and Separation from Wastes)
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10 pages, 12491 KiB  
Article
Improved Process for Separating TiO2 from an Oxalic-Acid Hydrothermal Leachate of Vanadium Slag
by Qingdong Miao, Ming Li, Guanjin Gao, Wenbo Zhang, Jie Zhang and Baijun Yan
Metals 2023, 13(1), 20; https://doi.org/10.3390/met13010020 - 22 Dec 2022
Cited by 1 | Viewed by 969
Abstract
In the present study, a process of separating high-quality TiO2 from an oxalic-acid leachate of vanadium slag was proposed. It consists of two steps; oxalic acid was firstly recovered from the leachate by the cooling-crystallization method, and subsequently TiO2 was separated [...] Read more.
In the present study, a process of separating high-quality TiO2 from an oxalic-acid leachate of vanadium slag was proposed. It consists of two steps; oxalic acid was firstly recovered from the leachate by the cooling-crystallization method, and subsequently TiO2 was separated from the oxalic-acid recovered leachate by the hydrothermal precipitation method. The experimental results indicate that oxalic acid can be recovered from the leachate by cooling crystallization at 5 °C, and after the recovery of oxalic acid, the purity of final TiO2 product can also be improved. For example, when the leachate was cooled directly at 5 °C for 5 h, about 7% of oxalic acid was recovered, and the purity of final TiO2 product improved from 95.7% to 96.6%. Furthermore, it was found that when some HCl solution was added to the leachate, both the recovery percentage of oxalic acid and the purity of TiO2 product increased. For instance, when 15 vol% of HCl solution relative to pregnant leachate was added, about 35% oxalic acid was recovered by cooling crystallization at 5 °C for 3 h, and the anatase TiO2 product with a purity of 99.2% was obtained by hydrothermal precipitation at 140 °C for 2.5 h. Full article
(This article belongs to the Special Issue Metal Recovery and Separation from Wastes)
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15 pages, 3458 KiB  
Article
Technology for Complex Processing of Electric Smelting Dusts of Ilmenite Concentrates to Produce Titanium Dioxide and Amorphous Silica
by Zaure Karshyga, Almagul Ultarakova, Nina Lokhova, Azamat Yessengaziyev, Kaisar Kassymzhanov and Maxat Myrzakulov
Metals 2022, 12(12), 2129; https://doi.org/10.3390/met12122129 - 11 Dec 2022
Cited by 2 | Viewed by 1142
Abstract
This paper presents the results of research on the development of a technology intended to process electric smelting dusts of ilmenite concentrate with the extraction of silicon and titanium and the production of products in the form of their dioxides. Dusts were processed [...] Read more.
This paper presents the results of research on the development of a technology intended to process electric smelting dusts of ilmenite concentrate with the extraction of silicon and titanium and the production of products in the form of their dioxides. Dusts were processed for silicon separation using the ammonium fluoride method. The optimum conditions for the fluorination and sublimation process of silicon compounds from the electric smelting dust of the ilmenite concentrate were determined: a temperature of 260 °С, a 6 h duration, and mass ratio of dust to ammonium bifluoride of 1:0.5 ÷ 0.9. The sublimation degree of silicon compounds was ~84–91%. The sublimation of titanium fluorides from the remaining sinter was carried out at a temperature of 600 ± 10 °C for 2 h, the mass ratio titanium-containing residue: ammonium bifluoride of 1:0.5, and the degree of sublimation of titanium fluorides was 99%. Iron, manganese, and chromium impurities in the sublimation of titanium fluorides sublimate to a rather low degree. Pyrohydrolysis of titanium fluoride sublimes at 600 °C and allows for the conversion of fluorides into titanium dioxide by 99.5% in 4–5 h. Titanium dioxide of rutile modification with 99.8% TiO2 was obtained after hydrochloric acid purification and calcination. A technological scheme for the complex processing of dust from the electric smelting of ilmenite concentrates with the production of silica and titanium dioxide is proposed. Full article
(This article belongs to the Special Issue Metal Recovery and Separation from Wastes)
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17 pages, 11232 KiB  
Article
Vacuum Carbon Reducing Iron Oxide Scale to Prepare Porous 316 Stainless Steel
by Fang Zhang, Jun Peng, Hongtao Chang and Yongbin Wang
Metals 2022, 12(12), 2118; https://doi.org/10.3390/met12122118 - 09 Dec 2022
Cited by 2 | Viewed by 1733
Abstract
In order to improve the added value of iron oxide scale and reduce the manufacturing cost of porous stainless steel, steel rolling iron oxide scale as an iron-containing raw material was used to prepare porous 316 stainless steel by high-temperature sintering under vacuum [...] Read more.
In order to improve the added value of iron oxide scale and reduce the manufacturing cost of porous stainless steel, steel rolling iron oxide scale as an iron-containing raw material was used to prepare porous 316 stainless steel by high-temperature sintering under vacuum conditions, while carbon was used as a reducing agent and pore-forming agent, and the necessary metal powders were added. In our work, the specific reduction system was confirmed, including the sintering temperature, sintering time, vacuum degree and carbon amount, through thermodynamic calculation combined with experiments. Thermodynamic analysis results showed that the transformation process of the chromium element in the raw materials at 10−4 atm and 300~1600 °C was FeCr2O4 + Cr3O4→Cr2O3 + Cr3O4 + Cr23C6→Cr23C6 + Cr7C3 + FCC→FCC + Cr23C6→FCC→FCC + BCC→Cr(liq). The FCC phase with qualified carbon content could be obtained at 10−4 atm and 1200 °C, while 90.88 g iron oxide scale, 17.17 g carbon, 17.00 g metal chromium, 12.00 g metal nickel and 2.5 g metal molybdenum were necessary to produce 100 g porous 316 stainless steel. The porous 316 stainless steel with a carbon content of 0.025% could be obtained at 10−4 atm and 1200 °C for 180 min, while the chromium element underwent the transformation of metal, Cr→FeCr2O4→Cr23C6→Austenite. The porosity of the porous 316 stainless steel was 42.07%. The maximum size of impurity particles was 5 μm when the holding time reached 180 min. Magnetic separation was an effective method to reduce impurities in the porous stainless steel. Full article
(This article belongs to the Special Issue Metal Recovery and Separation from Wastes)
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12 pages, 3536 KiB  
Article
Tin Removal from Tin-Bearing Iron Concentrate with a Roasting in an Atmosphere of SO2 and CO
by Lei Li, Zhipeng Xu and Shiding Wang
Metals 2022, 12(11), 1974; https://doi.org/10.3390/met12111974 - 18 Nov 2022
Cited by 1 | Viewed by 1024
Abstract
The tin could be volatilized and removed effectively from the tin-bearing iron concentrate while roasted in an atmosphere of SO2 and CO. The reduction of SO2 by CO occurred in preference to the SnO2 and Fe3O4, [...] Read more.
The tin could be volatilized and removed effectively from the tin-bearing iron concentrate while roasted in an atmosphere of SO2 and CO. The reduction of SO2 by CO occurred in preference to the SnO2 and Fe3O4, and the generated S2 could sulfurize the SnO2 to an evaporable SnS, which resulted in the tin volatilization. However, the Fe3O4 could be sulfurized simultaneously, and a phase of iron sulfide was formed, retaining in the roasted iron concentrate. It decreased the quality of the iron concentrate. In addition, the formation of Sn-Fe alloy was accelerated as the roasting temperature exceeded 1100 °C, which decreased the Sn removal ratio. An appropriate SO2 partial pressure and roasting temperature should be controlled. Under the condition of the roasting temperature of 1050 °C, SO2 partial pressure of 0.003, CO partial pressure of 0.85, and residence time of 60 min, the tin content in the roasted iron concentrate was decreased to 0.032 wt.% and the sulfur residual content was only 0.062 wt.%, which meets the standard of iron concentrate for BF ironmaking. Full article
(This article belongs to the Special Issue Metal Recovery and Separation from Wastes)
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13 pages, 7022 KiB  
Article
Synthesis of Ferroalloys via Mill Scale-Dross-Graphite Interaction: Implication for Industrial Wastes Upcycling
by Praphaphan Wongsawan, Weerayut Srichaisiriwech and Somyote Kongkarat
Metals 2022, 12(11), 1909; https://doi.org/10.3390/met12111909 - 07 Nov 2022
Cited by 2 | Viewed by 1456
Abstract
Mill scale and aluminum dross are the industrial wastes from steel and aluminum industries, which have high concentrations of Fe2O3 and Al2O3, respectively. This paper reports the conversion of reducible metal oxides in scale and dross [...] Read more.
Mill scale and aluminum dross are the industrial wastes from steel and aluminum industries, which have high concentrations of Fe2O3 and Al2O3, respectively. This paper reports the conversion of reducible metal oxides in scale and dross into an alloy via carbothermic reduction at 1550 °C. Scale and dross were mixed with graphite into three different C/O molar ratios of 1, 1.5, and 2 to produce a pellet. The pellets were heated at 1550 °C for up to 6 h under an argon atmosphere. By this method, carbothermic reductions were found to proceed and formed Fe–Si–Al–C alloy that consists of Fe3Al and Fe3Si phases. The presence of Si in the alloy came from the reduction of SiO2 in aluminum dross. Levels of Al and Si in the alloy increase with increasing C/O molar ratios. However, the Si level in the alloy was found to stabilize since 3 h, while the Al level increases with increasing time up to 6 h. Unreacted oxides in the wastes had an insignificant effect on the ferroalloy formation. These results provide evidence for carbothermic reduction of the Fe2O3-Al2O3-SiO2 system at 1550 °C and show the novel method to upcycling aluminum dross and mill scale toward a circular economy. Full article
(This article belongs to the Special Issue Metal Recovery and Separation from Wastes)
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17 pages, 4271 KiB  
Article
Selenium and Tellurium Separation: Copper Cementation Evaluation Using Response Surface Methodology
by Seyedreza Hosseinipour, Eskandar Keshavarz Alamdari and Nima Sadeghi
Metals 2022, 12(11), 1851; https://doi.org/10.3390/met12111851 - 29 Oct 2022
Cited by 4 | Viewed by 2244
Abstract
In recent years, high demands for Se and Te in the solar panels and semiconductors industry have encouraged its extraction from primary and secondary sources. However, the two elements’ similar chemical and physical properties make pure element production, Se or Te, arduous. This [...] Read more.
In recent years, high demands for Se and Te in the solar panels and semiconductors industry have encouraged its extraction from primary and secondary sources. However, the two elements’ similar chemical and physical properties make pure element production, Se or Te, arduous. This work is aimed to investigate the significant factors of Se and/or Te recovery in the copper cementation process using the response surface methodology. The test was carried out in two series, for Te and Se, so that H2SO4, CuSO4, Te(or Se) concentration, and temperature are the factors of experimentation. According to response surface methodology (RSM) results for both test series (i. e. Se and Te), 50 g/L H2SO4, 15 g/L Cu, and 35 °C, 3000 mg/L Se (or 750 mg/L Te) was specified for higher Se recovery (97%), and the lowest Te extraction (2%) as an optimum condition, so that could make a suitable separation process. Hence, the cementation test was conducted in the simultaneous presence of Se and Te, so the separation index became 5291. Moreover, the cementation test was carried out in the pregnant leach solution of copper anode slime, and the separation factor was measured to be 606. On the other hand, the thermodynamic evaluation and XRD patterns of the process’s sediments confirm that Se is precipitated as Cu2Se and Cu1.8Se, whereas no Te components are detected in the sediments. Full article
(This article belongs to the Special Issue Metal Recovery and Separation from Wastes)
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15 pages, 5503 KiB  
Article
Selective Disintegration–Milling to Obtain Metal-Rich Particle Fractions from E-Waste
by Ervins Blumbergs, Vera Serga, Andrei Shishkin, Dmitri Goljandin, Andrej Shishko, Vjaceslavs Zemcenkovs, Karlis Markus, Janis Baronins and Vladimir Pankratov
Metals 2022, 12(9), 1468; https://doi.org/10.3390/met12091468 - 01 Sep 2022
Cited by 8 | Viewed by 2242
Abstract
Various metals and semiconductors containing printed circuit boards (PCBs) are abundant in any electronic device equipped with controlling and computing features. These devices inevitably constitute e-waste after the end of service life. The typical construction of PCBs includes mechanically and chemically resistive materials, [...] Read more.
Various metals and semiconductors containing printed circuit boards (PCBs) are abundant in any electronic device equipped with controlling and computing features. These devices inevitably constitute e-waste after the end of service life. The typical construction of PCBs includes mechanically and chemically resistive materials, which significantly reduce the reaction rate or even avoid accessing chemical reagents (dissolvents) to target metals. Additionally, the presence of relatively reactive polymers and compounds from PCBs requires high energy consumption and reactive supply due to the formation of undesirable and sometimes environmentally hazardous reaction products. Preliminarily milling PCBs into powder is a promising method for increasing the reaction rate and avoiding liquid and gaseous emissions. Unfortunately, current state-of-the-art milling methods also lead to the presence of significantly more reactive polymers still adhered to milled target metal particles. This paper aims to find a novel and double-step disintegration–milling approach that can provide the formation of metal-rich particle size fractions. The morphology, particle fraction sizes, bulk density, and metal content in produced particles were measured and compared. Research results show the highest bulk density (up to 6.8 g·cm−3) and total metal content (up to 95.2 wt.%) in finest sieved fractions after the one-step milling of PCBs. Therefore, about half of the tested metallic element concentrations are higher in the one-step milled specimen and with lower adhered plastics concentrations than in double-step milled samples. Full article
(This article belongs to the Special Issue Metal Recovery and Separation from Wastes)
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10 pages, 18616 KiB  
Article
Optimization of Iron Recovery from BOF Slag by Oxidation and Magnetic Separation
by Mo Lan, Zhanwei He and Xiaojun Hu
Metals 2022, 12(5), 742; https://doi.org/10.3390/met12050742 - 27 Apr 2022
Cited by 5 | Viewed by 1910
Abstract
In order to solve the problem of solid waste pollution of basic oxygen furnace (BOF) slag in the metallurgical process, this paper took BOF slag as the research object, and carried out oxidation reconstruction of BOF slag and alcohol wet magnetic separation recovery [...] Read more.
In order to solve the problem of solid waste pollution of basic oxygen furnace (BOF) slag in the metallurgical process, this paper took BOF slag as the research object, and carried out oxidation reconstruction of BOF slag and alcohol wet magnetic separation recovery of iron phase, so as to efficiently recover and utilize BOF slag. In the early stages, the research group realized the transformation from weak magnetic iron oxide to strong magnetic magnesia-iron spinel phase in BOF slag through oxidation reconstruction experiments under different technological parameters. On this basis, different conditions in the magnetic separation process were adjusted to achieve the optimal iron recovery rate and grade in this paper. The experimental results show that, under the appropriate reconstruction temperature, with the increase of reaction time, gas flow rate and magnetic field intensity, the iron recovery will increase and the iron grade will decrease. The most suitable magnetic field intensity is 75 mT, the magnetic material yield is 46.00%, the iron grade is 29.10%, and the iron recovery is 64.12%. Compared with the initial steel slag, the iron grade increased by 8.22%, and the iron recovery increased by 46.38% compared with the direct magnetic separation without oxidation. Full article
(This article belongs to the Special Issue Metal Recovery and Separation from Wastes)
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16 pages, 3686 KiB  
Article
Fluoride Leaching of Titanium from Ti-Bearing Electric Furnace Slag in [NH4+]-[F−] Solution
by Fuqiang Zheng, Yufeng Guo, Feng Chen, Shuai Wang, Jinlai Zhang, Lingzhi Yang and Guanzhou Qiu
Metals 2021, 11(8), 1176; https://doi.org/10.3390/met11081176 - 24 Jul 2021
Cited by 5 | Viewed by 1551
Abstract
The effects of F− concentration, leaching temperature, and time on the Ti leaching from Ti-bearing electric furnace slag (TEFS) by [NH4+]-[F−] solution leaching process was investigated to reveal the leaching mechanism and kinetics of titanium. The results [...] Read more.
The effects of F− concentration, leaching temperature, and time on the Ti leaching from Ti-bearing electric furnace slag (TEFS) by [NH4+]-[F−] solution leaching process was investigated to reveal the leaching mechanism and kinetics of titanium. The results indicated that the Ti leaching rate obviously increased with the increase of leaching temperature and F− concentration. The kinetic equation of Ti leaching was obtained, and the activation energy was 52.30 kJ/mol. The fitting results of kinetic equations and calculated values of activation energy both indicated that the leaching rate of TEFS was controlled by surface chemical reaction. The semi-empirical kinetics equation was consistent with the real experimental results, with a correlation coefficient (R2) of 0.996. The Ti leaching rate reached 92.83% after leaching at 90 °C for 20 min with F− concentration of 14 mol/L and [NH4+]/[F−] ratio of 0.4. The leaching rates of Si, Fe, V, Mn, and Cr were 94.03%, 7.24%, 5.36%, 4.54%, and 1.73%, respectively. The Ca, Mg, and Al elements were converted to (NH4)3AlF6 and CaMg2Al2F12 in the residue, which can transform into stable oxides and fluorides after pyro-hydrolyzing and calcinating. Full article
(This article belongs to the Special Issue Metal Recovery and Separation from Wastes)
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Review

Jump to: Editorial, Research

20 pages, 2597 KiB  
Review
Vanadium and Nickel Recovery from the Products of Heavy Petroleum Feedstock Processing: A Review
by Aleksey Vishnyakov
Metals 2023, 13(6), 1031; https://doi.org/10.3390/met13061031 - 27 May 2023
Cited by 3 | Viewed by 2188
Abstract
The steadily growing demand for non-ferrous metals, a shift to heavier crude oil recovery and tightened environmental standards have increased the importance of heavy petroleum feedstock (HPF) as a raw source of metals. This paper reviews the recent developments in the recovery of [...] Read more.
The steadily growing demand for non-ferrous metals, a shift to heavier crude oil recovery and tightened environmental standards have increased the importance of heavy petroleum feedstock (HPF) as a raw source of metals. This paper reviews the recent developments in the recovery of vanadium and nickel from HPF. During crude oil processing and the application of its products, HPF is converted to various metal-enriched byproducts (“heavy oil”, petcoke, ashes and slags) from which the metals can be recovered. This paper briefly describes the sources and recovery pathways (both mainstream and exotic), and discusses the economic viability and possible future directions. Particular attention is paid to (i) the electrochemical recovery of metals from petrofluids and alternative approaches; (ii) pre-combustion metal recovery from petcoke; and (iii) metal reclamation from fly ash from heavy fuel oil or petroleum coke combustion: hydro- and pyro-metallurgical and bio-based techniques. The current stage of development and prospects for the future are evaluated for each method and summarized in the conclusion. Increasing research activity is mostly observed in traditional areas: metal extraction from fly ash and the reduction of metals from the ash to V–Fe and Ni–Fe alloys. Bioengineering approaches to recover vanadium from ashes are also actively developed and have the potential to become commercially viable in the future. Full article
(This article belongs to the Special Issue Metal Recovery and Separation from Wastes)
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60 pages, 12639 KiB  
Review
Chelating Extractants for Metals
by Pavel Yudaev and Evgeniy Chistyakov
Metals 2022, 12(8), 1275; https://doi.org/10.3390/met12081275 - 28 Jul 2022
Cited by 21 | Viewed by 5526
Abstract
In the present review, works on the classes of chelating extractants for metals, compounds with several amide and carboxyl groups, azomethines, oximes, macrocyclic compounds (crown ethers and calixarenes), phenanthroline derivatives, and others are systematized. This review focuses on the efficiency and selectivity of [...] Read more.
In the present review, works on the classes of chelating extractants for metals, compounds with several amide and carboxyl groups, azomethines, oximes, macrocyclic compounds (crown ethers and calixarenes), phenanthroline derivatives, and others are systematized. This review focuses on the efficiency and selectivity of the extractants in the recovery of metals from industrial wastewater, soil, spent raw materials, and the separation of metal mixtures. As a result of this study, it was found that over the past seven years, the largest number of works has been devoted to the extraction of heavy metals with amino acids (16 articles), azomethines and oximes (12 articles), lanthanids with amide compounds (15 articles), lanthanides and actinides with phenanthroline derivatives (7 articles), and noble metals with calixarenes (4 articles). Analysis of the literature showed that amino acids are especially effective for extracting heavy metals from the soil; thiodiglycolamides and aminocalixarenes for extracting noble metals from industrial waste; amide compounds, azomethines, oximes, and phenanthroline derivatives for extracting actinides; amide compounds for extracting lanthanides; crown ethers for extracting radioactive strontium, rhenium and technetium. The most studied parameters of extraction processes in the reviewed articles were the distribution ratios and separation factors. Based on the reviewed articles, it follows that chelate polydentate compounds are more efficient compounds for the extraction of metals from secondary resources compared to monodentate compounds. Full article
(This article belongs to the Special Issue Metal Recovery and Separation from Wastes)
17 pages, 1319 KiB  
Review
Extraction of the Rare Element Vanadium from Vanadium-Containing Materials by Chlorination Method: A Critical Review
by Shiyuan Liu, Weihua Xue and Lijun Wang
Metals 2021, 11(8), 1301; https://doi.org/10.3390/met11081301 - 17 Aug 2021
Cited by 15 | Viewed by 3943
Abstract
Vanadium as a rare element has a wide range of applications in iron and steel production, vanadium flow batteries, catalysts, etc. In 2018, the world’s total vanadium output calculated in the form of metal vanadium was 91,844 t. The raw materials for the [...] Read more.
Vanadium as a rare element has a wide range of applications in iron and steel production, vanadium flow batteries, catalysts, etc. In 2018, the world’s total vanadium output calculated in the form of metal vanadium was 91,844 t. The raw materials for the production of vanadium products mainly include vanadium-titanium magnetite, vanadium slag, stone coal, petroleum coke, fly ash, and spent catalysts, etc. Chlorinated metallurgy has a wide range of applications in the treatment of ore, slag, solid wastes, etc. Chlorinating agent plays an important role in chlorination metallurgy, which is divided into solid (NaCl, KCl, CaCl2, AlCl3, FeCl2, FeCl3, MgCl2, NH4Cl, NaClO, and NaClO3) and gas (Cl2, HCl, and CCl4). The chlorination of vanadium oxides (V2O3 and V2O5) by different chlorinating agents was investigated from the thermodynamics. Meanwhile, this paper summarizes the research progress of chlorination in the treatment of vanadium-containing materials. This paper has important reference significance for further adopting the chlorination method to treat vanadium-containing raw materials. Full article
(This article belongs to the Special Issue Metal Recovery and Separation from Wastes)
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