Electric Arc Furnace Dust Research Articles

Alternative Method for Treating Electric Arc Furnace Dust: Simulation and Life Cycle Assessment

The technical and environmental aspects of treating electric arc furnace dust (EAFD) using a novel process including alkaline roasting and organic acid leaching were evaluated and compared to the globally applied conventional Waelz process. The global warming potentials of the roasting–organic acid leaching process (with co-product credits) and the Waelz processes were 7.48 and 4.71 kg CO2-eq with 33% Zn dust as the feed material. However, with decreasing Zn content, the novel process become environmentally more competitive, and with 12% Zn, the corresponding GWP values were 6.31 and 9.26 kg CO2-eq. Co-product recovery decreased the net environmental impacts from the processing of the dust, which gave some benefits to the novel process. The Waelz process was observed to be energy intensive; however, the high consumption of leaching and roasting chemicals was the issue in the novel process. The excess caustic soda in the roasting step was observed to be a significant factor in the overconsumption of the organic acid in the leaching stage, and therefore, optimization of the roasting step is crucial. Other ways to decrease leaching chemical consumption include investigating the possibility to reuse the raffinate in leaching, or scrubbing the leach calcine from acid-consuming alkali. Evaluating the impacts of novel processes early enables iterative and agile process development and the directing the focus on the problem areas.Graphical

Selective dissolution of zinc and lead from electric arc furnace dust via oxidative thermolysis with polyvinyl chloride and water-leaching process

Electric arc furnace dust (EAFD) is a troublesome metallurgical waste accumulated worldwide in large quantities. In this work, EAFD mixed with polyvinyl chloride (EPVC) was thermally treated at 300 °C under air flow followed by leaching of solid residue in water at pH 5.6 and a temperature of 50 °C. Three sample geometries of EPVC mixtures were considered for thermal treatment stage (loose powder, pelleted thin disks and long cylinder shapes). Oxidative thermal treatment of EPVC mixture has resulted in oxidation of magnetite into hematite and prevented iron chloride formation while both zinc and lead were completely chlorinated. The degree of magnetite oxidation was more pronounced when loose powder was used. The subsequent leaching of the thermal treatment of the loose powder EPVC has resulted in 100% recovery of zinc into leaching solution, while iron recovery was close to 0% at optimal conditions. When the EPVC mixture was pelletized into thin disk or cylindrical shape, the access of oxygen was hindered resulting in incomplete oxidation of magnetite or iron chloride to a non-leachable Fe2O3, which did not completely inhibit iron leaching. Iron recoveries in the post water leaching stage of EPVC residue treated under oxidative environment were found to be 21.6, 8.6 and 0.26% for long cylinder, thin disks, and loose powder, respectively. However, 46% of iron content was leached when a cylindrical shape mixture was thermally treated under inert conditions. These important findings can be utilized for the co-thermal treatment of EAFD and PVC wastes towards sustainable recycling of these wastes.

Facile synthesis of zinc ferrite as adsorbent from high‑zinc electric arc furnace dust

A facile route was proposed to prepare zinc ferrite as a heavy-metal adsorption material from high‑zinc electric arc furnace (EAF) dust by roasting it directly with the addition of low-cost Fe2O3, followed by purification via dilute acid leaching. The effect of the addition of Fe2O3, revealed by the Fe/Zn molar ratio, on the formation of zinc ferrite was investigated. The results showed that adding Fe2O3 could increase the percentage of acid-insoluble zinc in the form of zinc ferrite to 94.13% after roasting at 1000 °C for 2 h with the Fe/Zn molar ratio of 1.8. After removing Ca2ZnSi2O7 impurity and nano bead milling, the product could be used as a good adsorbent due to its superior adsorption capacities of 198.26 mg/g, 24.95 mg/g, and 151.45 mg/g for Pb (II), Cr (VI), and Cd (II), respectively. This study offered a novel method for overall and value-added utilization of EAF dust.

Phase Transformation and Zinc Extraction from Zinc Ferrite by Calcium Roasting and Ammonia Leaching Process

Zinc ferrite (ZnFe2O4), one of the major forms of zinc in electric arc furnace dust and zinc leaching residue, is very difficult to chemically dissolve in either acidic or alkaline solutions. It is therefore necessary to study the extraction of zinc from zinc ferrite to achieve the full recovery of the zinc resources. In this paper, CaO was used to degrade the structure of zinc ferrite and then the ammonia leaching method was applied to recover zinc. The thermodynamic analysis indicated that the zinc ferrite could react with CaO to form zinc oxide and dicalcium ferrite. The CaO–Fe2O3–ZnO phase diagram shows that Ca2Fe2O5 can be in equilibrium with ZnO rather than ZnFe2O4 at a higher CaO area. The experimental results indicated that the phase transformation of zinc ferrite, reacted with CaO, to zinc oxide and dicalcium ferrite could be completely achieved with a CaO addition of 2.4:1 (mole ratio). The peaks of zinc ferrite in the X-ray diffraction (XRD) patterns cannot be clearly observed after calcium roasting at 1220 °C for 2 h. The ammonia leaching tests showed that the zinc leaching rate was about 90% under optimal roasting conditions.

Carbon coated electric arc furnace dust prepared by one-pot pyrolysis: An efficient, low carbon footprint electrode material for lithium-ion batteries

This work offers useful insights into the evaluation of the electric arc furnace dust in green energy applications by surface engineering. To produce low-carbon-footprint electrodes, for the first time in the open literature, the practical pyrolysis (of sucrose) method is applied to create a nanometer-thick carbon layer over the dust. Advanced techniques are used to characterize the carbon-coated electric arc furnace flue dust morphologically, structurally, and chemically. Galvanostatic tests reveal that the carbon-coated dust exhibits 600 mAh g−1 discharge capacity after 250 cycles. The rate test proves that the carbon-coated dust can withstand a high current load (2A g−1) and delivers 540 mAh g−1 after 250 cycles when the current load is decreased to 0.1A g−1. This obtained capacity shows that with the correct material selection and process design, it is possible to produce low-carbon footprint electrodes at a low cost. Electrochemical characterizations indicate that the lithiation reaction of the carbon-coated dust takes place similarly to that of the anode materials which are made of synthetically fabricated carbon-coated transition metal oxides and/or ferrites. It is anticipated that this study sets an example for the valorization of the various industrial wastes in energy applications in the future.

Valorization of a hazardous waste with 3D-printing: Combination of kaolin clay and electric arc furnace dust from the steel making industry

Electric arc furnace steel dust (EAFD) waste has been studied as a complementary byproduct material for kaolin-based clays fabricated with additive manufacturing via the direct ink writing technology. The combination of clay with steel dust has a positive contribution to the environment because this waste can be stabilized, and the corresponding pollution reduced. EAFD is classified as a hazardous waste from the metallurgical industry with millions of tons not properly disposed or used worldwide. The research presented in this investigation evaluate the use EAFD as an admixture for clay ceramics to produce three-dimensional printed (3DP) parts. The cylindrical specimens fabricated involved not only different water to clay ratios but also waste contents from 0 wt% to 20 wt%. After a sintering processing in an air atmosphere, samples were treated during 2 h at 1100 °C, and later tested in compression tests. Other conducted characterization tests were density, scanning electron microscopy, rheology, Weibull statistics, and creep analysis. The main contribution of this research to the literature is the valorization of the EAFD hazardous waste as a material for 3D printing.

Spent Mushroom Substrate and Electric Arc Furnace Dust Recycling by Carbothermic Reduction Method.

With recent increases in environmental awareness, the circular economy concept, which involves turning waste into usable products, has gradually become widely accepted. Spent mushroom substrate (SMS) is an agricultural waste that lacks recycling channels in Taiwan. This study explored the feasibility of simultaneously recycling two completely different types of waste: spent mushroom substrate (SMS), an agricultural waste, and electric-arc furnace dust (EAFD), an industrial waste. Specifically, SMS was used to replace metallurgical coke as a reducing agent for EAFD, which underwent carbothermic reduction to recycle valuable metallic Zn. The results showed that if SMS and EAFD were mixed at a C/O ratio of 0.8, the degree of Zn removal achieved 95% at 1100 °C, which is 150 °C lower than the reduction temperature of the EAFD-coke mixture (due to volatile matter (VM) in SMS). For the reduction of ZnO in EAFD, with the assistance of VM in SMS, the C/O ratio can be decreased from 0.8 to 0.16 at 1300 °C, achieving a high degree of Zn removal over 95%. In addition, the torrefaction of SMS increased the fixed carbon content and improved the Zn productivity at the same C/O ratio, reaching almost the same productivity as the coke sample (SMS torrefaction = 500 °C, C/O = 0.8, reduction = 1200 °C, Zn removal~99%). Finally, CO2 emission reductions from the use of SMS were also estimated.

Steel Manufacturing EAF Dust as a Potential Adsorbent for Hydrogen Sulfide Removal.

Electric arc furnace dust (EAFD) is a high-volume steel manufacturing byproduct with currently limited value-added applications. EAFD contains metal oxides that can react with H2S to form stable sulfides. Hence, the valorization potential of EAFD as an adsorbent material for syngas H2S removal was investigated. EAFD from European steel plants was characterized and tested in dynamic H2S breakthrough tests and benchmarked against a commercial ZnO-based adsorbent. For this, the EAFD was first processed into adsorbents by simple milling and granulation steps. The EAFD samples exhibited sulfur capture capacities at 400 °C and an SV of 17,000 h–1 that correlated with the sample milling times and Zn concentrations. It was verified that only zinc participated in sulfur capture. Yet, both ZnO and the zinc in ZnFe2O4 were found to be active in sulfidation. At higher temperatures (500 and 600 °C), EAFD sample performance drastically improved and even exceeded the reference zinc oxide performance. The high-zinc (48% by mass) EAFD-B sample exhibited the highest tested performance at 500 °C, with a sulfur capture capacity of 234 mg g–1. The results indicate that sufficiently high-zinc-content EAFD could serve as a viable sulfur capture material.

Recycling of zinc and lead from electric arc furnace dust by selective leaching with EDTA

ABSTRACT Electric Arc Furnace Dust (EAFD) is a potential source of contamination, primarily by the non- ferrous metals as it may contain (Zn, Pb). It is known that steel processing companies make efforts to reuse EAFD, however, today, the implementation of the most common hydrometallurgical methods is considered to be harmful and corrosive. In that sense, a more ecological and efficient technique for the management of this industrial waste is proposed here. The technique consists in the use of an organic solution of ethylenediaminetetraacetic acid (EDTA) at moderate conditions (room temperature, 0.5 M maximum concentration and 2 h of operation) for zinc and lead extraction. To leach metals using EDTA at pH 3 and 6 is possible and favourable. The presence of ZnFe2O4 did not allow leaching of the total zinc present in EAFD, while the rapid dissolution of PbO allowed more than 95% lead extraction.

Kinetic Investigation of Self-reducing Briquettes of Electric Arc Furnace Dust Produced with Charcoals

Kinetic Investigation of Self-reducing Briquettes of Electric Arc Furnace Dust Produced with Charcoals

Kinetic Analysis of Recovering Zinc from Electric Arc Furnace Dust by Vacuum Carbothermic Reduction at 20 Pa

Electric arc furnace dust (EAFD) presents a contamination hazard due to its heavy metal leachability. The traditional disposal methods of landfill or stacking not only pose a threat to the environment but also waste metal resources. This paper adopted vacuum carbothermic reduction to dispose of EAFD and the zinc metal could be obtained as a product. The reduction ratios of the EAFD were carried out under various reaction temperatures and times at 20 Pa. Furthermore, the kinetics of the reduction process was also studied. The reduction ratio of the reaction process can be facilitated through increasing the temperature or lengthening the time and can reach up to 99.6% under the condition of 1373 K with 60 min. The zinc ferrite and zinc oxide were reduced first and then iron oxide reduction occurred. The reduction process could be divided into three stages: Stage 1 involved the direct reduction of zinc ferrite and zinc oxide, and the control step was the phase boundary reaction with the apparent activation energy of 48.54 kJ/mol; Stage 2 involved the reduction of zinc oxide and iron oxide, and the control step was also the phase boundary reaction with the apparent activation energy of 56.27 kJ/mol; Stage 3 involved the escape of gas phase products and the control step was diffusion with the apparent activation energy of 105.3 kJ/mol.

Assessment of Solid Wastes and By‐Products as Solid Particle Materials for Concentrated Solar Power Plants

The revalorization of solid wastes and by‐products to be applied as solid particles in concentrated solar power (CSP) leads to cost savings and progresses toward more sustainable technology. Herein, the physicochemical, morphological, thermal, and solar absorption properties are evaluated for electric arc furnace dust, black slag from the steel industry, and Gossan waste from the Rio Tinto mining industry. The principal objectives of this work are (i) to carry out a thermal aging at 900 °C at different times, (ii) to assess the solid's stability throughout the evaluation of physicochemical, morphological, thermal, and optical properties of the material as received, after 300 and 500 h of thermal aging, and (iii) to determine the most appropriate candidate as a thermal energy storage medium and heat transfer fluid for the CSP concept with solid particles. The results show that electric arc furnace black slag is the most suitable candidate from the three solids studied, as it is the one that optimizes the combination of absorptance, thermal conductivity, and chemical stability after thermal aging.

Thermodynamic Analysis of Electric Arc Furnace Dust Reduction by Volatile Matter of Non-Coking Coal

Thermodynamic Analysis of Electric Arc Furnace Dust Reduction by Volatile Matter of Non-Coking Coal

Utilization of electric arc furnace dust as a filler for unsaturated polyester resin

Electric Arc Furnace Dust (EAFD) is a waste material produced during the steelmaking process. It contains a large amount of valuable metal oxides that can be used as a filling additive to improve the polymer properties. In this study, EAFD is used as a filler to the unsaturated polyester (UP) resin in different weight percentages. Neat UP and UP/EAFD compounds were studied mechanically by testing their tensile, impact, flexural, and hardness properties. The samples were investigated physically by density and water absorption, in addition to flammability analysis was performed by testing the Limiting Oxygen Index (LOI). Finally, the thermal properties were determined using Thermogravimetric Analysis (TGA). The result showed that the incorporation of the EAFD particles into the UP matrix has significantly affected the mechanical properties by increasing tensile strength up to 42%. The hardness of the UP/EAFD composites increases up to 8.5% and reaches a maximum value at 10 wt% of EAFD. Flexural strength and impact strength showed an optimal value at 5 wt% of EAFD. The flammability of the composites decreased by 34% at 30 wt% of EAFD. The thermal stability of the composites showed a remarkable increasing trend. Therefore, utilizing EAFD in UP matrix would help improve the environmental pollution control of the steel industry. Finding useful applications of this dust as a filler for the composite industry might convert this hazardous waste into a byproduct that should reduce the expenses and increase their profit.

A Review on Processing of Electric Arc Furnace Dust (EAFD) by Pyro-Metallurgical Processes

A Review on Processing of Electric Arc Furnace Dust (EAFD) by Pyro-Metallurgical Processes

Influence of Different Carbon Content on Reduction of Zinc Oxide via Metal Bath

Electric arc furnace dust (EAFD) is an important secondary resource for the zinc industry. The most common process for its recycling is the pyro-metallurgical treatment in the Waelz process. However, this process focuses on the recycling of the zinc, whereas the recovery of other metals from the EAFD—such as iron and other alloying elements—is neglected. An up-to-date version of reprocessing can involve multi-metal recycling by means of a metal bath containing carbon. The use of a liquid iron alloy requires a higher processing temperature, which enables the reduction and melting of iron oxides as well as other compounds occurring in the dust. Furthermore, the Zn yield is higher and the reduction kinetics are faster than in the Waelz process. This paper is only focused on the zinc reduction in such a metal bath. In order to determine the influence of the carbon content in the molten metal on the reduction rate, experiments were carried out on the reduction behavior of zinc oxide using a synthetic slag. This slag, with a basicity B2 = 1, was applied to an iron bath with varying carbon contents. (0.85%, 2.16%, 2.89%, and 4.15%) The decrease in the zinc oxide concentration was monitored, along with the reaction rates calculated from these data. It was found that the reaction rate increases with rising carbon content in the melt.

Investigation of hazardous waste a case study of electric arc furnace dust characterization

Dust from an electric arc furnace is formed as the main by-product of the steel production process from the secondary iron-based raw materials. This dust has significant contents of Zn and Fe, as well as Pb, Cd, Ca, Mg, Cr, Mn, Si, Ni, Cu, F, Cl and other elements and is considered hazardous industrial solid waste since it contains heavy metals. In order to protect the environment and public health from the negative impact of this type of hazardous waste, it is necessary, even mandatory, to carry out its treatment in accordance with the legislation of the country where it is located. Before applying any treatment of the electric arc furnace (EAF) dust, it is necessary to perform its detailed characterization. In this paper, the following characterization of EAF dust originating in the Republic of Serbia was performed: physical-mechanical and chemical characterization, determination of granulometric composition, and mineralogical characterization. Also, the EAF dust impact on the environment and human health was assessed (Leachability and Toxicity Characteristic Leaching Procedure (TCLP) tests). The results have shown that the Zn content is in the range 32 to 35 % and that the main mineralogical phases of the dust are zincite, franklinite, magnetite, and magnesioferrite. Granulometric analysis has shown that 80 % of the sample consists of particles less than 26 ?m in size. According to the leaching test results, the EAF dust is characterized as a hazardous waste due to the increased chloride content, while the TCLP test indicated dust toxicity due to the increased contents of Zn, Cd, and Pb.

Synthesis of ZnO nanoparticles from electric arc furnace dust

This paper presents a hydrometallurgical treatment of electric arc furnace (EAF) dust taken from a Vietnamese steelmaking plant to obtain zinc oxide (ZnO) nanoparticles by using aqueous ammonium carbonate solution as a leaching agent. Characterization of the EAF dust was conducted by XRD technique, SEM observation, and manual wet chemical analysis. The results showed that total zinc (Zn) of the dust was 42.69 wt.% and existed mainly in the forms of zincite - ZnO, simonkolleite - Zn5(OH)8Cl2H2O, and franklinite - ZnFe2O4. The leached condition, in which the ammoniac carbonate concentration was 300 g/l and the time was 90 minutes, was found to provide the highest leaching efficiency of 85.29 % when the temperature was fixed at 60 oC and the ratio of solid/liquid was 1/6. After some steps of the subsequent treatment, the ZnO nanoparticles with the purity of 99.5 % and the size of 100 nm were obtained from thermal decomposition of zinc carbonate hydroxide - Zn5(CO3)2(OH)6.

Efficient extraction and separation of zinc and iron from electric arc furnace dust by roasting with FeSO4·7H2O followed by water leaching

Electric arc furnace dust (EAFD) formed during steelmaking in electric arc furnace is rich in iron and zinc. Due to the negative effects of zinc, directly recycling as raw materials for ironmaking does not work so that it is still mostly accumulated. In this study, a novel process was proposed, wherein EAFD was roasted with FeSO4·7H2O followed by water leaching for the effective and selective extraction and separation of zinc and iron from EAFD. The optimal roasting conditions were determined as mass ratio of FeSO4·7H2O/EAFD of 1.5, roasting temperature of 675 °C, holding time of 3 h. The transfer mechanism of elements in EAFD was analyzed. 98.79% of zinc and only 0.11% of iron were dissolved in the leaching solution, respectively, avoiding the iron-removing step before the subsequent zinc electrodeposition. Meanwhile, most of Ca, Mg and Mn ions transformed into corresponding sulfates during roasting experiments and then entered leaching solution after water leaching. Thus, the leaching residue with 91.36% mass ratio of Fe2O3 could be applied as raw material for ironmaking industry. In addition, the majority of heavy metals (Pb and Cr) were remained and immobilized in the leaching residue, meeting the requirement of leaching toxicity standard. Results from this work provide a new insight into selective recovery of valuable metals from EAFD while at the same time exploiting the solid waste of Copperas.

Investigation of selective leaching conditions of ZnO, ZnFe2O4 and Fe2O3 in electric arc furnace dust in HNO3

Electric arc furnace dust (EAFD) includes mainly Zn, Fe, Pb, Ca and Mn-bearing compounds. Thus, EAFD is classified as a hazardous waste. The dissolution behavior of Zn- and Fe-bearing compounds in EAFD in nitric acid solutions was investigated in this work. The composition of Zn- and Fe-bearing compounds in the EAFD was determined as 28.58, 37.96 and 11.33 % for ZnO, ZnFe2O4 and Fe2O3, respectively. The effect of stirring speed, temperature and HNO3 concentration on the dissolution rate of ZnO, ZnFe2O4 and Fe2O3 were investigated and optimum leaching conditions determined. While ZnO was dissolved rapidly, the dissolution rate of ZnFe2O4 increased with increasing temperature and HNO3 concentration. Fe2O3 was not soluble in 0.5 M HNO3 solution at 40?C, whereas it was dissolved completely in 4 M HNO3 solution at 80?C.