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Chedrewih M, Thiery V, Gauthier A, Amin F. Incorporation of antimony-bearing mining wastes into clinker Portland raw feed: The difficulty of Sb analysis in calcium silicates. J Microsc 2024; 294:66-74. [PMID: 37706543 DOI: 10.1111/jmi.13228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 09/12/2023] [Accepted: 09/12/2023] [Indexed: 09/15/2023]
Abstract
Within the global trend to valorise various mineral wastes as substituents in Portland cement clinker raw feed, mining wastes are promising candidates. However, they might still contain high levels of metallic elements. Their fate in the kiln is not always understood as well as their incorporation within the various clinker's phases. This is especially the case for antimony. Its in situ microanalysis by the means of energy-dispersive spectroscopy is tricky since several of its L lines (Lα1 = 3604,72 eV, Lα2 = 3595,32 eV) overlap with calcium lines (Kα1 = 3691,68 eV, Kα2 = 3688,09 eV). Hence, at low concentrations, it is not possible to visualise its characteristics peaks. Increasing the counting rate by increasing the acceleration current results in the generation of spurious sum peaks, rendering the analysis not viable. Wavelength dispersive spectroscopy (i.e. electron microprobe) allows a better spectral resolution and quantification of Sb in the clinker phases. In a Portland cement clinker doped with 1% of Sb-bearing mining waste, the Sb2O3 content in belite and alite is in the 0.2-0.4 wt.% range as well as for C3A; in C4AF the content is higher, from 1.4 wt.% to 2 wt.%. However, there are microstructural evidence that Sb forms blebs from less than 1 μm in diameter up to 10 μm, included in calcium silicates. Hence, its incorporation in the lattice of calcium silicates is dubious. However, for ferrites and aluminates there is no microstructural evidence for remaining Sb-bearing phases, suggesting a direct incorporation in crystal lattices.
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Affiliation(s)
- Migueli Chedrewih
- Centre for Materials and Processes, IMT Nord Europe, Institut Mines-Télécom, Lille, France
- LGCgE - Laboratoire de Génie Civil et géoEnvironnement, Institut Mines-Télécom, University of Lille, Lille, France
| | - Vincent Thiery
- Centre for Materials and Processes, IMT Nord Europe, Institut Mines-Télécom, Lille, France
- LGCgE - Laboratoire de Génie Civil et géoEnvironnement, Institut Mines-Télécom, University of Lille, Lille, France
| | - Arnaud Gauthier
- LGCgE - Laboratoire de Génie Civil et géoEnvironnement, Institut Mines-Télécom, University of Lille, Lille, France
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Staněk T, Rybová A, Boháč M, Bartoníčková E, Palovčík J. The effect of the combined addition of copper, lithium and sulphur on the formation of Portland cement clinker. J Microsc 2024; 294:225-232. [PMID: 38558054 DOI: 10.1111/jmi.13293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 03/06/2024] [Accepted: 03/19/2024] [Indexed: 04/04/2024]
Abstract
Both copper and lithium act as strong fluxes and lower the temperature of the clinker melt formation. Sulphur promotes the stabilisation of more hydraulically active modification of alite M1. It is expected that this combination could produce an alite clinker at significantly lower temperatures with high quality technological parameters. In this paper, the effect of combined oxides of copper, lithium and sulphur addition on the phase composition and clinker structure of Portland cement was investigated. The reference raw meal was prepared from common cement raw materials. Each of the mentioned oxides was added to the reference raw meal in two different concentrations, and 8 combinations were prepared. Chemically pure compounds (NH4)2SO4, CuO and Li2CO3 were used as a source of these oxides. The raw meals were burned to equilibrium at 1450°C. Their phase composition was determined by X-ray diffraction analysis, the microstructure was monitored by optical microscopy, and the microchemistry of the clinker phases was observed by electron microscopy with EDS analysis. It was found that in samples with high lithium or copper content, there is an increase in belite and free lime at the expense of alite. The combination of Cu + Li has the most negative effect, followed by Li alone and Cu alone. The higher SO3 content slightly offsets this negative effect.
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Affiliation(s)
- Theodor Staněk
- Binder systems, Research Institute for Building Materials, Brno, Czech Republic
| | - Alexandra Rybová
- Binder systems, Research Institute for Building Materials, Brno, Czech Republic
| | - Martin Boháč
- Binder systems, Research Institute for Building Materials, Brno, Czech Republic
| | - Eva Bartoníčková
- Faculty of Chemistry, Brno University of Technology, Brno, Czech Republic
| | - Jakub Palovčík
- Faculty of Chemistry, Brno University of Technology, Brno, Czech Republic
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Antunes M, Santos RL, Horta RB, Colaço R. Novel Amorphous-Wollastonitic Low-Calcium Hydraulic Binders: A State-of-the-Art Review. Materials (Basel) 2023; 16:4874. [PMID: 37445188 DOI: 10.3390/ma16134874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 06/24/2023] [Accepted: 07/04/2023] [Indexed: 07/15/2023]
Abstract
Because of the severe environmental impact of the CO2 emissions associated with the production of ordinary Portland cement (OPC) and the increasing demand for this commodity material, the development of alternative products has become a global concern. One alternative to OPC, or alitic-based clinkers, are amorphous-wollastonitic low-calcium hydraulic binders (AWLCs). This new class of hydraulic binders, described in the literature for the first time in 2015, may significantly reduce the CO2 emissions associated with its production, resulting from its lower calcium content, but also from the fact that its production technology can be fully electrified. In this paper, a state-of-the-art review is presented, providing a comprehensive description of the latest research, summarizing both the physicochemical and mechanical characteristics of this type of hydraulic binder, as well as possible routes for its production at an industrial scale.
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Affiliation(s)
- Mónica Antunes
- Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal
- IDMEC-Instituto de Engenharia Mecânica, University of Lisbon, 1049-001 Lisbon, Portugal
| | - Rodrigo L Santos
- CIMPOR-Cimentos de Portugal, SGPS S.A., 1099-020 Lisbon, Portugal
| | - Ricardo B Horta
- Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal
| | - Rogério Colaço
- Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal
- IDMEC-Instituto de Engenharia Mecânica, University of Lisbon, 1049-001 Lisbon, Portugal
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Weinbruch S, Scerri M, Eduard W, Thomassen Y, Nordby KC, Berlinger B, Dahl K, Friisk G, Romanova N, Notø H. Chemical Composition of Thoracic Dust at Workplaces During Cement Production. Ann Work Expo Health 2023. [PMID: 36866437 DOI: 10.1093/annweh/wxad011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023] Open
Abstract
OBJECTIVES Cement belongs to the most used building materials. Clinker is the major constituent of cement, and it is believed that the strong increase of pH after hydration of clinker minerals is responsible for the observed decline in lung function of cement production workers. Information on clinker exposure at workplaces in the cement production industry is scarse. The aims of this study are to determine the chemical composition of thoracic dust and to quantify workplace exposure to clinker in cement production. METHODS The elemental composition of 1250 personal thoracic samples collected at workplaces in 15 plants located in 8 different countries (Estonia, Greece, Italy, Norway, Sweden, Switzerland, Spain, Turkey) was determined by inductively coupled plasma optical emission spectrometry (ICP-OES), separately for water- and acid-soluble fraction. Positive matrix factorization (PMF) was used to determine the contribution of different sources to the dust composition and to quantify the clinker content in 1227 of the thoracic samples. In addition, 107 material samples were analysed to facilitate interpretation of the factors obtained by PMF. RESULTS The median thoracic mass concentrations varied for individual plants between 0.28 and 3.5 mg/m3. PMF with 8 water-soluble and 10 insoluble (i.e., acid-soluble) element concentrations yielded a five-factor solution: Ca, K, Na sulfates; silicates; insoluble clinker; soluble clinker-rich; and soluble Ca-rich. The clinker content of the samples was calculated as sum of the insoluble clinker and soluble clinker-rich factors. The median clinker fraction of all samples was 45% (range 0-95%), and varied between 20% and 70% for individual plants. DISCUSSION The 5-factor solution of PMF was selected on the basis of several mathematical parameters recommended in the literature as well as the mineralogical interpretability of the factors. In addition, interpretation of the factors was supported by the measured apparent solubility of Al, K, Si, Fe, and to a lesser extent Ca in material samples. The total clinker content obtained in the present study is considerably lower than estimates based on the Ca concentrations in a sample, and somewhat lower than estimates based on Si concentrations after selective leaching with a methanol/maleic acid mixture. The clinker abundance in workplace dust of one plant investigated in the present contribution was also estimated in a recent study by electron microscopy, and the good agreement between both studies gives confidence in the results of PMF. CONCLUSIONS The clinker fraction in personal thoracic samples could be quantified from the chemical composition by positive matrix factorization. Our results allow for further epidemiological analyses of health effects in the cement production industry. As these estimates are more accurate for clinker exposure than aerosol mass, stronger associations with respiratory effects are expected if clinker is the main cause of these effects.
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Affiliation(s)
- Stephan Weinbruch
- National Institute of Occupational Health, Gydas vei 8, N-0363 Oslo, Norway.,Institute of Applied Geosciences, Technical University Darmstadt, Schnittspahnstr. 9, D-64287 Darmstadt, Germany
| | - Mark Scerri
- Environmental Management & Planning Division, Institute of Earth Systems, University of Malta, Msida MSD2080, Malta
| | - Wijnand Eduard
- National Institute of Occupational Health, Gydas vei 8, N-0363 Oslo, Norway
| | - Yngvar Thomassen
- National Institute of Occupational Health, Gydas vei 8, N-0363 Oslo, Norway
| | | | - Balázs Berlinger
- National Institute of Occupational Health, Gydas vei 8, N-0363 Oslo, Norway
| | - Kari Dahl
- National Institute of Occupational Health, Gydas vei 8, N-0363 Oslo, Norway
| | - Grete Friisk
- National Institute of Occupational Health, Gydas vei 8, N-0363 Oslo, Norway
| | - Natalya Romanova
- National Institute of Occupational Health, Gydas vei 8, N-0363 Oslo, Norway
| | - Hilde Notø
- National Institute of Occupational Health, Gydas vei 8, N-0363 Oslo, Norway
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Martínez-Martínez S, Pérez-Villarejo L, Eliche-Quesada D, Sánchez-Soto PJ. New Types and Dosages for the Manufacture of Low-Energy Cements from Raw Materials and Industrial Waste under the Principles of the Circular Economy and Low-Carbon Economy. Materials (Basel) 2023; 16:802. [PMID: 36676541 PMCID: PMC9863668 DOI: 10.3390/ma16020802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/06/2023] [Accepted: 01/10/2023] [Indexed: 06/17/2023]
Abstract
The cement manufacturing industry is one of the main greenhouse gas emission producers and also consumes a large quantity of raw materials. It is essential to reduce these emissions in order to comply with the Paris Agreement and the principles of the circular economy. The objective of this research was to develop different types of cement clinker blends using industrial waste and innovative design to produce low-energy cement. Several types of waste have been studied as alternative raw materials. Their main characteristics have been analyzed via X-ray fluorescence (XRF), X-ray diffraction (XRD), Attenuated total reflectance Fourier trans-form infrared spectroscopy (ATR-FTIR), thermal analysis (TG-DTG-DSC) and scanning electron microscopy and energy dispersive X-ray spectroscopy analysis (SEM-EDS). The results obtained from the experimental work carried out in this research focused on the study of crude blends for low-energy cement created from industrial waste. The effect of the addition of different industrial waste types, as a substitution for raw materials, in the production of low-energy cement with high dicalcium silicate content has been investigated. Thus, the dosage design has been performed using modified Bogue equations and quality indexes (LSF, AM, and SM). The calculations of both the modified Bogue equations and quality indexes necessitate knowledge of the weight percentages of CaO, SiO2, Al2O3, and Fe2O3, determined via XRF. In this theoretical design of the different blends, it has been established that a dicalcium silicate ratio of 60-65 wt % and an LSF of 78-83% as the limit are values common to all of them. The calculation basis for the crude blends has been based on calcined materials. Therefore, the chemical composition was established, following this premise. Thus, it was possible to develop cement clinker blends with compositions of 50 wt % and 100 wt % using industrial wastes. This research has shown that the clinkerization process is one of the main options for the valorization of waste and its consideration for inclusion as a raw material within the circularity of the cement industry's production process. Thus, waste is used as a raw material for the production of a more useful substance, taking into account the fundamental principles of the circular economy.
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Affiliation(s)
- Sergio Martínez-Martínez
- Department of Chemical, Environmental and Materials Engineering, University of Jaén, Campus Las Lagunillas s/n, 23071 Jaén, Spain
- Institute of Materials Science of Sevilla (ICMS), Joint Center of the Spanish National Research Council (CSIC), University of Sevilla, 41092 Sevilla, Spain
| | - Luis Pérez-Villarejo
- Department of Chemical, Environmental and Materials Engineering, University of Jaén, Campus Las Lagunillas s/n, 23071 Jaén, Spain
| | - Dolores Eliche-Quesada
- Department of Chemical, Environmental and Materials Engineering, University of Jaén, Campus Las Lagunillas s/n, 23071 Jaén, Spain
| | - Pedro J. Sánchez-Soto
- Institute of Materials Science of Sevilla (ICMS), Joint Center of the Spanish National Research Council (CSIC), University of Sevilla, 41092 Sevilla, Spain
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Bădănoiu A, Moanță A, Dumitrescu O, Nicoară AI, Trușcă R. Waste Glass Valorization as Raw Material in the Production of Portland Clinker and Cement. Materials (Basel) 2022; 15:7403. [PMID: 36295468 PMCID: PMC9611181 DOI: 10.3390/ma15207403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 10/11/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023]
Abstract
The paper presents experimental results regarding the synthesis of Portland clinker starting from raw mixes based on two types of clayey precursors, i.e., clay and marl (the most common types of raw materials used in the cement industry), with and without glass waste content. The soda-lime glass waste addition (5.36-5.59 wt %), used to control the silica ratio of the raw mix, improved the raw mix burnability and decreased the calcination temperature (by 20 °C), leading to a decrease in fuel consumption and contributing to the reduction in CO2 emissions associated with clinker and cement production. The clinkers obtained by the calcination of raw mixes with glass waste content at 1430 °C with a 30 min plateau had a similar mineralogical composition and microstructure to the clinkers obtained from the reference raw mixes and fulfilled the requirements of the specific standard EN 197-1. The obtained clinkers were used to produce two types of Portland cement, i.e., a unitary cement (CEM I) and a binary blended cement with slag (CEM II/B-S). The main characteristics of these cements, i.e., loss on ignition, insoluble residue, sulfate and chloride contents, as well as the setting time and soundness, meet the conditions stipulated in the EN 197-1 standard. The values of compressive strength, assessed on mortars after 2, 7 and 28 days of curing, allow the classification of all CEM I cements in the 42.5 R class. In the case of CEM II/B-S cements, those obtained from raw mixes with clay can be classified in the 42.5 N class, while those obtained from raw mixes with marl are classified in the 32.5 R class.
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Affiliation(s)
- Alina Bădănoiu
- Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, 011061 Bucharest, Romania
| | - Adriana Moanță
- CEPROCIM S.A. Preciziei No. 6, 062203 Bucharest, Romania
| | - Ovidiu Dumitrescu
- Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, 011061 Bucharest, Romania
- National Research Center for Micro and Nanomaterials, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, 060042 Bucharest, Romania
| | - Adrian Ionuț Nicoară
- Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, 011061 Bucharest, Romania
- National Research Center for Micro and Nanomaterials, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, 060042 Bucharest, Romania
| | - Roxana Trușcă
- Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, 011061 Bucharest, Romania
- National Research Center for Micro and Nanomaterials, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, 060042 Bucharest, Romania
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Wojtacha-Rychter K, Smoliński A. Multi-Case Study on Environmental and Economic Benefits through Co-Burning Refuse-Derived Fuels and Sewage Sludge in Cement Industry. Materials (Basel) 2022; 15:ma15124176. [PMID: 35744235 PMCID: PMC9229322 DOI: 10.3390/ma15124176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 05/25/2022] [Accepted: 06/10/2022] [Indexed: 01/29/2023]
Abstract
The use of waste as an energy source in cement clinker production is a promising way to transition toward a circular economy and limit carbon dioxide (CO2) in the atmosphere. The cement industry is responsible for around 5% of global CO2 emissions. In this paper, the analysis of environmental and economic profits associated with the substitution of coal by two refuse-derived fuels (RDF) and sewage sludge (SS) in a cement kiln was presented. Differences in the fuel-related CO2 emissions were calculated for two-, three-, and four-component fuel blends based on the fuel consumption data, heating values, and the correspondent emission factors. The biogenic fraction content of 19% and 43% were measured in RDFs. The material balance of fuels with the assumed technological parameters of the cement clinker production installation (capacity of 6000 Mg per day and unit heat of 3.6 GJ) shows that the RDF heat substitution at the level of 90% allows for a saving of approximately 28.6 Mg per hour of coal, and to manage even approx. 40 Mg per hour of RDF. The increase in the share of SS in the total heat consumption to 6% contributed to reducing the actual emissions by 17 kg of CO2 per 1 Mg of clinker. Multilateral benefits due to the use of RDF in the cement plant were evident.
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Affiliation(s)
| | - Adam Smoliński
- Central Mining Institute, Pl. Gwarków 1, 40-166 Katowice, Poland
- Correspondence:
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Hattaf R, Benchikhi M, Azzouzi A, El Ouatib R, Gomina M, Samdi A, Moussa R. Preparation of Cement Clinker from Geopolymer-Based Wastes. Materials (Basel) 2021; 14:6534. [PMID: 34772060 DOI: 10.3390/ma14216534] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 09/25/2021] [Accepted: 09/28/2021] [Indexed: 11/25/2022]
Abstract
In order to avoid potential environmental pollution from geopolymer-based material wastes, this work investigated the feasibility of using these materials as alternative raw materials in the preparation of cement clinker. The geopolymer binders and mortars were used as substitutes for natural mineral clays since they are rich in silica and alumina. Simulated geopolymer wastes were prepared by the activation of metakaolin or fly ash by an alkaline silicate solution. The cement-clinkers fired at 1450 °C for 1h were characterized by XRD, XRF, SEM-EDS, and a free lime (CaOf) content test. The anhydrous clinker mineral phases C3S (Ca3SiO5), C2S (Ca2SiO4), C3A (Ca3Al2O6), and C4AF (Ca4Al2Fe2O10) were well-crystallized in all investigated formulations. The free lime was lower than 1.3 wt% in all elaborated clinkers, which indicates a high degree of clinkerization. The results demonstrate that geopolymer binder and mortar materials are suitable substitutes for natural mineral clay incement clinker preparation.
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Diliberto C, Meux E, Diliberto S, Garoux L, Marcadier E, Rizet L, Lecomte A. A zero-waste process for the management of MSWI fly ashes: production of ordinary Portland cement. Environ Technol 2020; 41:1199-1208. [PMID: 30231770 DOI: 10.1080/09593330.2018.1525434] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 09/09/2018] [Indexed: 06/08/2023]
Abstract
Municipal solid waste incineration (MSWI) fly ashes are hazardous waste since they contain organic pollutants, heavy metals and an important amount of various soluble salts. However their chemical composition is interesting for their valorization in cement production. The objective of this paper is to assess the possibility of MSWI fly ashes reuse as cement raw meal, after pre-treatment, at a laboratory scale. The environmental impact has also been studied (analyses of the metals, of dioxins and furans and leaching tests on clinker produced). Experimental results show that the replacement of MSWI fly ash could be taken up to 30% in the raw mixes, according to the chemical composition of the MSWI fly ashes. This substitution is also to be refined according to the content of hazardous elements contents. This study also shows that the pre-treatment must be well carried out in order to limit the alkaline contents which may affect the quality of the cementitious phases.
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Affiliation(s)
- Cécile Diliberto
- Institut Jean Lamour, UMR/CNRS 7198, Université de Lorraine, Equipe 'Matériaux pour le Génie Civil', IUTNB, Villers-lès-Nancy, France
| | - Eric Meux
- Institut Jean Lamour, UMR/CNRS 7198, Université de Lorraine, Equipe 'Chimie et Electrochimie des Matériaux', Metz cedex 3, France
| | - Sébastien Diliberto
- Institut Jean Lamour, UMR/CNRS 7198, Université de Lorraine, Equipe 'Chimie et Electrochimie des Matériaux', Metz cedex 3, France
| | - Laetitia Garoux
- Institut Jean Lamour, UMR/CNRS 7198, Université de Lorraine, Equipe 'Chimie et Electrochimie des Matériaux', Metz cedex 3, France
| | | | | | - André Lecomte
- Institut Jean Lamour, UMR/CNRS 7198, Université de Lorraine, Equipe 'Matériaux pour le Génie Civil', IUTNB, Villers-lès-Nancy, France
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Fan H, Lv M, Wang X, Xiao J, Mi X, Jia L. Effect of Cr on the Mineral Structure and Composition of Cement Clinker and Its Solidification Behavior. Materials (Basel) 2020; 13:ma13071529. [PMID: 32225053 PMCID: PMC7177747 DOI: 10.3390/ma13071529] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 03/19/2020] [Accepted: 03/24/2020] [Indexed: 11/16/2022]
Abstract
In order to reveal the solidification behavior of Cr in the cement clinker mineral phase, 29Si magic-angle spinning nuclear magnetic resonance, X-ray diffraction, and scanning electron microscopy with energy-dispersive X-ray spectroscopy techniques were used to analyze the morphology and composition of the cement clinker mineral phase doped with Cr. The results showed that the addition of Cr did not change the chemical environment of 29Si in the clinker mineral phase, and it was still an isolated silicon–oxygen tetrahedron. Cr affected the orientation of the silicon–oxygen tetrahedron and the coordination number of calcium, leading to the formation of defects in the crystal structure of the clinker mineral phase, by replacing Ca2+ into the mineral phase lattice to form a new mineral phase Ca3Cr2(SiO4)3. Cr acted as a stabilizer for the formation of β-C2S in the clinker calcination. As the amount of Cr increased, the relative content of C3S decreased and the relative content of C2S increased. Further, Cr easily dissolved in C2S, while it was not found in C3S. This study is conducive to further research on the mechanism of heavy metal solidification in cement clinker. Furthermore, it is important to evaluate the environmental risk of heavy metals in the process of sludge disposal through cement kiln and promote the utilization of sludge resources and the sustainable development of the cement industry.
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Li J, Jiang Z, Li W. Preparation and Self-Healing Properties of Clinker/PVP Microsphere in Cement Paste. Materials (Basel) 2020; 13:ma13030589. [PMID: 32012765 PMCID: PMC7040679 DOI: 10.3390/ma13030589] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 01/18/2020] [Accepted: 01/23/2020] [Indexed: 11/16/2022]
Abstract
This paper presents a new insight into the autolytic mineral self-healing method for cementitious materials. The clinker/PVP (polyvinyl pyrrolidone) autolytic microsphere was prepared via the film coating method with cement clinker as a healing agent and PVP as the autolytic coating film. The morphology and chemical structure of the microsphere were characterized by environmental scanning electron microscopy (FESEM) equipped with energy dispersive spectrometer (EDS) and Fourier transform infrared spectroscopy (FTIR), respectively. The clinker retaining original mineral healing composition was successfully coated with a PVP film confirmed by FTIR. The maximum film thickness was 7.54 μm, which was determined by laser particle size measurement. The autolytic behavior was measured using isothermal calorimetry and successfully controlled by pretreatment degree (i.e., silane coupling agent amount). Experimental results showed that the compressive strength recovery of cement paste with a 30% microsphere was 54% higher than ordinary cement paste specimens. The damage degree of the specimen was also decreased by adding the autolytic microsphere.
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Yang Z, Zhang Y, Liu L, Seetharaman S, Wang X, Zhang Z. Integrated Utilization of Sewage Sludge and Coal Gangue for Cement Clinker Products: Promoting Tricalcium Silicate Formation and Trace Elements Immobilization. Materials (Basel) 2016; 9:ma9040275. [PMID: 28773400 PMCID: PMC5502968 DOI: 10.3390/ma9040275] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Revised: 03/09/2016] [Accepted: 03/30/2016] [Indexed: 11/16/2022]
Abstract
The present study firstly proposed a method of integrated utilization of sewage sludge (SS) and coal gangue (CG), two waste products, for cement clinker products with the aim of heat recovery and environment protection. The results demonstrated that the incremental amounts of SS and CG addition was favorable for the formation of tricalcium silicate (C3S) during the calcinations, but excess amount of SS addition could cause the impediment effect on C3S formation. Furthermore, it was also observed that the C3S polymorphs showed the transition from rhombohedral to monoclinic structure as SS addition was increased to 15 wt %. During the calcinations, most of trace elements could be immobilized especially Zn and cannot be easily leached out. Given the encouraging results in the present study, the co-process of sewage sludge and coal gangue in the cement kiln can be expected with a higher quality of cement products and minimum pollution to the environment.
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Affiliation(s)
- Zhenzhou Yang
- Beijing Key Laboratory for Solid Waste Utilization and Management and Department of Energy and Resource Engineering, College of Engineering, Peking University, Beijing 100871, China.
| | - Yingyi Zhang
- Beijing Key Laboratory for Solid Waste Utilization and Management and Department of Energy and Resource Engineering, College of Engineering, Peking University, Beijing 100871, China.
| | - Lili Liu
- Beijing Key Laboratory for Solid Waste Utilization and Management and Department of Energy and Resource Engineering, College of Engineering, Peking University, Beijing 100871, China.
| | - Seshadri Seetharaman
- Department of Materials Science Engineering, Royal Institute of Technology, Stockholm SE 100-4, Sweden.
| | - Xidong Wang
- Beijing Key Laboratory for Solid Waste Utilization and Management and Department of Energy and Resource Engineering, College of Engineering, Peking University, Beijing 100871, China.
| | - Zuotai Zhang
- Beijing Key Laboratory for Solid Waste Utilization and Management and Department of Energy and Resource Engineering, College of Engineering, Peking University, Beijing 100871, China.
- School of Environmental Science and Engineering, South University of Science and Technology of China, Shenzhen 518055, China.
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