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Riley AL, Cameron J, Burke IT, Onnis P, MacDonald JM, Gandy CJ, Crane RA, Byrne P, Comber S, Jarvis AP, Hudson-Edwards KA, Mayes WM. Environmental behaviour of iron and steel slags in coastal settings. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:42428-42444. [PMID: 38877192 PMCID: PMC11219386 DOI: 10.1007/s11356-024-33897-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 05/31/2024] [Indexed: 06/16/2024]
Abstract
Iron and steel slags have a long history of both disposal and beneficial use in the coastal zone. Despite the large volumes of slag deposited, comprehensive assessments of potential risks associated with metal(loid) leaching from iron and steel by-products are rare for coastal systems. This study provides a national-scale overview of the 14 known slag deposits in the coastal environment of Great Britain (those within 100 m of the mean high-water mark), comprising geochemical characterisation and leaching test data (using both low and high ionic strength waters) to assess potential leaching risks. The seaward facing length of slag deposits totalled at least 76 km, and are predominantly composed of blast furnace (iron-making) slags from the early to mid-20th Century. Some of these form tidal barriers and formal coastal defence structures, but larger deposits are associated with historical coastal disposal in many former areas of iron and steel production, notably the Cumbrian coast of England. Slag deposits are dominated by melilite phases (e.g. gehlenite), with evidence of secondary mineral formation (e.g. gypsum, calcite) indicative of weathering. Leaching tests typically show lower element (e.g. Ba, V, Cr, Fe) release under seawater leaching scenarios compared to deionised water, largely ascribable to the pH buffering provided by the former. Only Mn and Mo showed elevated leaching concentrations in seawater treatments, though at modest levels (<3 mg/L and 0.01 mg/L, respectively). No significant leaching of potentially ecotoxic elements such as Cr and V (mean leachate concentrations <0.006 mg/L for both) were apparent in seawater, which micro-X-Ray Absorption Near Edge Structure (μXANES) analysis show are both present in slags in low valence (and low toxicity) forms. Although there may be physical hazards posed by extensive erosion of deposits in high-energy coastlines, the data suggest seawater leaching of coastal iron and steel slags in the UK is likely to pose minimal environmental risk.
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Affiliation(s)
- Alex L Riley
- School of Environmental Sciences, University of Hull, Kingston upon Hull, UK.
| | - James Cameron
- School of Environmental Sciences, University of Hull, Kingston upon Hull, UK
| | - Ian T Burke
- School of Earth and Environment, University of Leeds, Leeds, UK
| | - Patrizia Onnis
- Environment and Sustainability Institute and Camborne School of Mines, University of Exeter, Penryn, UK
| | - John M MacDonald
- School of Geographical and Earth Sciences, University of Glasgow, Glasgow, UK
| | - Catherine J Gandy
- School of Engineering, Newcastle University, Newcastle upon Tyne, UK
| | - Richard A Crane
- Environment and Sustainability Institute and Camborne School of Mines, University of Exeter, Penryn, UK
| | - Patrick Byrne
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, UK
| | - Sean Comber
- School of Geography, Earth and Environmental Sciences, University of Plymouth, Plymouth, UK
| | - Adam P Jarvis
- School of Engineering, Newcastle University, Newcastle upon Tyne, UK
| | - Karen A Hudson-Edwards
- Environment and Sustainability Institute and Camborne School of Mines, University of Exeter, Penryn, UK
| | - William M Mayes
- School of Environmental Sciences, University of Hull, Kingston upon Hull, UK
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2
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Ahmed MJ, Cuijpers R, Schollbach K, Van Der Laan S, Van Wijngaarden-Kroft M, Verhoeven T, Brouwers HJH. V and Cr substitution in dicalcium silicate under oxidizing and reducing conditions - Synthesis, reactivity, and leaching behavior studies. JOURNAL OF HAZARDOUS MATERIALS 2023; 442:130032. [PMID: 36166903 DOI: 10.1016/j.jhazmat.2022.130032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 09/13/2022] [Accepted: 09/17/2022] [Indexed: 06/16/2023]
Abstract
Dicalcium silicate (C2S) is known to incorporate potentially hazardous metals (Cr and V) in a belite-rich cementitious system. The effect of the electrovalence nature of V and Cr on C2S polymorphs' (α´, β, γ) stability under oxidizing and reducing conditions as well as their reactivity are systematically investigated via analyzing oxidation states, phase composition, bonding system, and microstructure as well as oxide composition quantitively. It is shown that C2S can incorporate Cr (VI) and V(V) consequently leading to stabilization of α´, β-C2S. Instead, Cr (II, III) and V < (V) tend not to substitute in C2S. Despite reactive polymorphs (α´, β-C2S) stability due to Cr (VI) and V(V) incorporation, the early age (48-72 h) C2S reactivity is drastically reduced due to Cr (VI) and V (V) incorporation. Moreover, one batch leaching test revealed that the V (V) leaching is inversely proportional to aqueous Ca2+ ion at pH > 12 while Cr leaching is sensitive to its oxidation state, and dissolution of C2S. Even though C2S can incorporate Cr (VI) and V (V) ions, the final leaching is governed by the immobilization potential of C-S-H gel, pH as well as types of calcium chromate and vanadate complexes.
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Affiliation(s)
- Muhammad Jawad Ahmed
- Department of Built Environment, Eindhoven University of Technology, Eindhoven, the Netherlands.
| | - Remco Cuijpers
- Department of Built Environment, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - Katrin Schollbach
- Department of Built Environment, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - Sieger Van Der Laan
- Tata Steel, R&D, Microstructure & Surface Characterization (MSC), IJmuiden, the Netherlands
| | | | - Tiny Verhoeven
- Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - H J H Brouwers
- Department of Built Environment, Eindhoven University of Technology, Eindhoven, the Netherlands
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Chen Z, Cang Z, Yang F, Zhang J, Zhang L. Carbonation of steelmaking slag presents an opportunity for carbon neutral: A review. J CO2 UTIL 2021. [DOI: 10.1016/j.jcou.2021.101738] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Luo Y, He D. Research status and future challenge for CO 2 sequestration by mineral carbonation strategy using iron and steel slag. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:49383-49409. [PMID: 34331652 DOI: 10.1007/s11356-021-15254-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 06/28/2021] [Indexed: 06/13/2023]
Abstract
Mineral carbonation can simultaneously realize the effective treatment of CO2 and iron and steel slag; thus, it is of great significance for the low carbon and sustainable development of iron and steel industry. In this article, the researches of mineral carbonation process using iron and steel slag as feedstock are reviewed, and the carbonation reaction mechanism and the parameters affecting the reaction rate and carbonation degree are analyzed. Furthermore, the effect of different enforcement approaches, such as ultrasonic enhancement, mixed calcination, microbial enhancement, and cyclic coprocessing on mineral carbonation reaction, is introduced. The additional effects of mineral carbonation, such as solving the problem of poor volume stability of steel slag, weakening the leaching of heavy metal ions, and reducing the pH of the leachate, are also illustrated. Moreover, issues related to mineral carbonation technology that should be emphasized upon soon, such as the production of valuable products, use of industrial wastewater, aqueous phase recycling use, multiparameter coupling analysis, and research on the properties of carbonation residues, are also discussed, which contribute some perspectives to the future development of mineral carbonation of iron and steel slag.
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Affiliation(s)
- Yinbo Luo
- Department of Ferrous Metallurgy, School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Dongfeng He
- Department of Ferrous Metallurgy, School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
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Imashuku S, Nagasako M, Wagatsuma K. Effect of Reheating and Quenching on the Cathodoluminescence Intensity of Free Lime in Steelmaking Slag. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2021; 27:1-7. [PMID: 33993899 DOI: 10.1017/s1431927621000374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Determining free lime content in steelmaking slag is crucial for its safe reuse in road construction. A simple method has been recently developed to rapidly derive this value via cathodoluminescence (CL) imaging of steelmaking slag, previously quenched from 1,000°C to room temperature, according to the illuminated areas corresponding to free lime (luminescence peak at 600 nm). This quenching is required to obtain intense CL from free lime, but the mechanism of such signal enhancement is still unknown. Therefore, the present study investigated the mechanism by comparing the microstructures, CL images, and CL spectra of free lime in quenched and unquenched steelmaking slag. Large amounts of defects, including dislocations, were observed in the free lime emitting intense luminescence at 600 nm, whereas the samples without clear CL exhibited only a few defects. These results and previous studies suggest that the luminescence at 600 nm from free lime is enhanced by the CL originating from oxygen vacancies (380 nm); therefore, the enhancement of the intensity of the free lime CL peak could be attributed to the increase in the oxygen vacancies via quenching from 1,000°C to room temperature.
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Affiliation(s)
- Susumu Imashuku
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai980-8577, Japan
| | - Makoto Nagasako
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai980-8577, Japan
| | - Kazuaki Wagatsuma
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai980-8577, Japan
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Pullin H, Bray AW, Burke IT, Muir DD, Sapsford DJ, Mayes WM, Renforth P. Atmospheric Carbon Capture Performance of Legacy Iron and Steel Waste. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:9502-9511. [PMID: 31317734 PMCID: PMC6706800 DOI: 10.1021/acs.est.9b01265] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 07/15/2019] [Accepted: 07/18/2019] [Indexed: 06/10/2023]
Abstract
Legacy iron (Fe) and steel wastes have been identified as a significant source of silicate minerals, which can undergo carbonation reactions and thus sequester carbon dioxide (CO2). In reactor experiments, i.e., at elevated temperatures, pressures, or CO2 concentrations, these wastes have high silicate to carbonate conversion rates. However, what is less understood is whether a more "passive" approach to carbonation can work, i.e., whether a traditional slag emplacement method (heaped and then buried) promotes or hinders CO2 sequestration. In this paper, the results of characterization of material retrieved from a first of its kind drilling program on a historical blast furnace slag heap at Consett, U.K., are reported. The mineralogy of the slag material was near uniform, consisting mainly of melilite group minerals with only minor amounts of carbonate minerals detected. Further analysis established that total carbon levels were on average only 0.4% while average calcium (Ca) levels exceeded 30%. It was calculated that only ∼3% of the CO2 sequestration potential of the >30 Mt slag heap has been utilized. It is suggested that limited water and gas interaction and the mineralogy and particle size of the slag are the main factors that have hindered carbonation reactions in the slag heap.
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Affiliation(s)
- Huw Pullin
- School
of Earth and Ocean Sciences, Cardiff University, Cardiff CF10 3AT, United Kingdom
| | - Andrew W. Bray
- School
of Earth and Environment, University of
Leeds, Leeds LS2 9JT, United Kingdom
| | - Ian T. Burke
- School
of Earth and Environment, University of
Leeds, Leeds LS2 9JT, United Kingdom
| | - Duncan D. Muir
- School
of Earth and Ocean Sciences, Cardiff University, Cardiff CF10 3AT, United Kingdom
| | - Devin J. Sapsford
- School
of Engineering, Cardiff University, Cardiff CF24 3AA, United Kingdom
| | - William M. Mayes
- Department
of Geography, Geology and Environment, University
of Hull, Hull HU6 7RX, United Kingdom
| | - Phil Renforth
- School
of Engineering and Physical Sciences, Heriot-Watt
University, Edinburgh EH14 4AS, United Kingdom
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Hobson AJ, Stewart DI, Bray AW, Mortimer RJG, Mayes WM, Riley AL, Rogerson M, Burke IT. Behaviour and fate of vanadium during the aerobic neutralisation of hyperalkaline slag leachate. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 643:1191-1199. [PMID: 30189535 DOI: 10.1016/j.scitotenv.2018.06.272] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/15/2018] [Accepted: 06/22/2018] [Indexed: 06/08/2023]
Abstract
Vanadium is a toxic metal present in alkaline leachates produced during the weathering of steel slags. Slag leaching can therefore have deleterious effects on local watercourses due to metal toxicity, the effects of the high pH (9-12.5) and rapid carbonation (leading to smothering of benthic communities). We studied the fate and behaviour of V in slag leachate both through field observations of a heavily affected stream (Howden Burn, Consett UK) and in controlled laboratory experiments where slag leachates were neutralised by CO2 ingassing from air. V was found to be removed from leachates downstream from the Howden Burn source contemporaneously with a fall in pH, Ca, Al and Fe concentrations. In the neutralisation experiments pH reduced from 12 → 8, and limited quantities of V were incorporated into precipitated CaCO3. The presence of kaolinite clay (i.e. SiOH and AlOH surfaces) during neutralisation experiments had no measureable effect on V uptake in the alkaline to circumneutral pH range. XANES analysis showed that V was present in precipitates recovered from experiments as adsorbed or incorporated V(V) indicating its likely presence in leachates as the vanadate oxyanion (HVO42-). Nano-scale particles of 2-line ferrihydrite also formed in the neutralised leachates potentially providing an additional sorption surface for V uptake. Indeed, removal of V from leachates was significantly enhanced by the addition of goethite (i.e. FeOOH surfaces) to experiments. EXAFS analysis of recovered goethite samples showed HVO42- was adsorbed by the formation of strong inner-sphere complexes, facilitating V removal from solution at pH < 10. Results show that carbonate formation leads to V removal from leachates during leachate neutralisation, and the presence of both naturally occurring and neoformed Fe (oxy)hydroxides provide a potent sink for V in slag leachates, preventing the spread of V in the environment.
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Affiliation(s)
- Andrew J Hobson
- School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
| | | | - Andrew W Bray
- School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
| | - Robert J G Mortimer
- School of Animal, Rural and Environmental Sciences, Nottingham Trent University, Brackenhurst Campus, Southwell, Nottinghamshire NG25 0QF, UK
| | - William M Mayes
- School of Environmental Sciences, University of Hull, Hull HU6 7RX, UK
| | - Alex L Riley
- School of Environmental Sciences, University of Hull, Hull HU6 7RX, UK
| | - Michael Rogerson
- School of Environmental Sciences, University of Hull, Hull HU6 7RX, UK
| | - Ian T Burke
- School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK.
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Hobson AJ, Stewart DI, Mortimer RJG, Mayes WM, Rogerson M, Burke IT. Leaching behaviour of co-disposed steel making wastes: Effects of aeration on leachate chemistry and vanadium mobilisation. WASTE MANAGEMENT (NEW YORK, N.Y.) 2018; 81:1-10. [PMID: 30527025 DOI: 10.1016/j.wasman.2018.09.046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 08/24/2018] [Accepted: 09/28/2018] [Indexed: 06/09/2023]
Abstract
Steelmaking wastes stored in landfill, such as slag and spent refractory liners, are often enriched in toxic trace metals (including V). These may become mobile in highly alkaline leachate generated during weathering. Fresh steelmaking waste was characterised using XRD, XRF, and SEM-EDX. Batch leaching tests were performed under aerated, air-excluded and acidified conditions to determine the impact of atmospheric CO2 and acid addition on leachate chemistry. Phases commonly associated with slag including dicalcium silicate, dicalcium aluminoferrite, a wüstite-like solid solution and free lime were identified, as well as a second group of phases including periclase, corundum and graphite which are representative of refractory liners. During air-excluded leaching, dissolution of free lime and dicalcium silicate results in a high pH, high Ca leachate in which the V concentration is low due to the constraint imposed by Ca3(VO4)2 solubility limits. Under aerated conditions, carbonation lowers the leachate pH and provides a sink for aqueous Ca, allowing higher concentrations of V to accumulate. Below pH 10, leachate is dominated by periclase dissolution and secondary phases including monohydrocalcite and dolomite are precipitated. Storage of waste under saturated conditions that exclude atmospheric CO2 would therefore provide the optimal environment to minimise V leaching during weathering.
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Affiliation(s)
- Andrew J Hobson
- School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
| | | | - Robert J G Mortimer
- School of Animal, Rural and Environmental Sciences, Nottingham Trent University, Brackenhurst Campus, Southwell, Nottinghamshire NG25 0QF, UK
| | - William M Mayes
- School of Environmental Sciences, University of Hull, Hull HU6 7RX, UK
| | - Mike Rogerson
- School of Environmental Sciences, University of Hull, Hull HU6 7RX, UK
| | - Ian T Burke
- School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK.
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