scholarly journals Component Modification of Basic Oxygen Furnace Slag with C4AF as Target Mineral and Application

2021 ◽  
Vol 13 (12) ◽  
pp. 6536
Author(s):  
Yanrong Zhao ◽  
Pengliang Sun ◽  
Ping Chen ◽  
Xiaomin Guan ◽  
Yuanhao Wang ◽  
...  
Keyword(s):  
Intermediate Phase ◽  
Raw Materials ◽  
Activity Index ◽  
Basic Oxygen Furnace ◽  
Hydration Products ◽  
Basic Oxygen ◽  
Bof Slag ◽  
Mineral Compositions ◽  
Slag Component ◽  
Basic Oxygen Furnace Slag

In this paper, a new method of basic oxygen furnace (BOF) slag component modification with a regulator was studied. The main mineral was designed as C4AF, C2S and C3S in modified BOF slag, and the batching method, mineral compositions, hydration rate, activation index and capability of resisting sulfate corrode also were studied. XRD, BEI and EDS were used to characterize the mineral formation, and SEM was used to study the morphology of hydration products. The results show that most inert phase in BOF slag can be converted into active minerals of C4AF and C2S through reasonable batching calculation and the amount of regulating agent. The formation of C4AF and C2S in modified BOF slag is better, and a small amount of MgO is embedded in the white intermediate phase, but C3S is not detected. With the increase in the CaO/SiO2 ratio in raw materials, the CaO/SiO2 ratio of calcium silicate minerals in modified BOF slag increases, the contents of f-CaO are less than 1.0%, and the activity index improves. Compared with the BOF slag, the activity index and exothermic rate of modified BOF slag improved obviously, and the activity index of 90 days is close to 100%. With the increase in modified BOF slag B cement, the flexural strength decrease; however, the capability of resisting sulfate corrode is improved due to the constant formation of a short rod-like shape ettringite in Na2SO4 solution and the improvement of the structure densification of the hydration products.

scholarly journals Utilization of Basic Oxygen Furnace Slag in Geopolymeric Coating for Passive Radiative Cooling Application

2020 ◽  
Vol 12 (10) ◽  
pp. 3967 ◽  
Author(s):  
Chia-Ho Wu ◽  
Chih-Hong Huang ◽  
Yeou-Fong Li ◽  
Wei-Hao Lee ◽  
Ta-Wui Cheng
Keyword(s):  
Layer Structure ◽  
Research Work ◽  
Temperature Drop ◽  
Basic Oxygen Furnace ◽  
Radiative Cooling ◽  
Portland Cement Concrete ◽  
Basic Oxygen ◽  
Bof Slag ◽  
Basic Oxygen Furnace Slag ◽  
Furnace Slag

Basic oxygen furnace slag (BOFs) is difficult to reutilize because it contains excessive free lime, and thus causes serious expansion. For this reason, how to reuse BOF slag has turned out to be an imperative issue in order to meet the concept of a circular economy. The key intention of this research work is to develop a new way to reutilize BOF slag, which due to its high emissivity in the 8–13 µm wavelength range, can be used as a sustainable, passive radiative cooling material. Passive radiative cooling, without the consumption of any energy, achieves the cooling of a surface by reflecting the sunlight and radiating the heat throughout the outer space (not absorbed by the atmosphere). BOF slag is used as a radiative cooling material in geopolymeric coating. This coating possesses an emissivity of 0.95 within the range of 8–13 µm and also has high conductivity, but its gray appearance absorbs too much heat. Therefore, by improving the situation through a double-layer structure, a temperature drop of 5.9 °C was reached compared to non-coated concrete under simulated sunlight, simultaneously with a low heating rate and high cooling rate. Besides, the binding strength between the geopolymeric coating and Portland cement concrete is comparable to two commercial organic paints. It is highly probable that the utilization of BOF slag in geopolymeric coating is energy saving and also feasible for passive radiative cooling applications. Hence, it can greatly decrease indoor temperature and improve the comfort of people living in buildings.

Applying Basic Oxygen Furnace Slag in Porous Asphalt Pavement

2011 ◽  
Vol 243-249 ◽  
pp. 4195-4200 ◽  
Author(s):  
Jyh Dong Lin ◽  
C. T. Hung ◽  
Shih Huang Chen ◽  
Ming Chin Yeh
Keyword(s):  
Swelling Pressure ◽  
Basic Oxygen Furnace ◽  
Basic Oxygen ◽  
Porous Asphalt ◽  
New Process ◽  
Porous Pavement ◽  
Bof Slag ◽  
Perpetual Pavement ◽  
Pavement Construction ◽  
Basic Oxygen Furnace Slag

The benefit using BOF slag on Perpetual Pavement that has been developed in United States and Europe recently, will effectively increasing Rutting and Skid Resistance of Pavement, reducing the amount of asphalt that used on Mix Design that will reduce the overall construction cost. The character of BOF slag has higher density and Hydrophilic, this study applied it to porous pavement. It compared with the performance of traditional aggregates. Based on the result, there are no significant differences. The BOF slag will be expansion with water, it was bad in pavement construction. Through swelling pressure test, the BOF slag with new process is no significant change in water. So, BOF slag is suitable in porous pavement.

scholarly journals Recycling of Basic Oxygen Furnace Slag as a Raw Material for Autoclaved Aerated Concrete Production

2020 ◽  
Vol 12 (15) ◽  
pp. 5896
Author(s):  
Ying-Liang Chen ◽  
Chun-Ta Lin
Keyword(s):  
Basic Oxygen Furnace ◽  
Essential Elements ◽  
Raw Material ◽  
Basic Oxygen ◽  
Autoclaved Aerated Concrete ◽  
Concrete Production ◽  
Bof Slag ◽  
Aerated Concrete ◽  
Basic Oxygen Furnace Slag ◽  
Furnace Slag

The purpose of this study was to recycle basic oxygen furnace (BOF) slag in the production of autoclaved aerated concrete (AAC), and to examine the influence on the properties of AAC products. The magnetic substances in the BOF slag accounted for about 15 wt.% and the magnetic proportion increased as the particle size decreased. The nonmagnetic portion of the BOF slag was acquired by a magnetic separation process and its major constituents were Ca (~42 wt.% as CaO) and Si (~35 wt.% as SiO2), which are the essential elements of AAC. When using the BOF slag for AAC production, the bulk density and compressive strength of the specimens decreased as the amount of slag increased. The results of the performance analysis revealed that at appropriate water–solids ratios, using 15 wt.% or less of the BOF slag was beneficial to the properties of the AAC products. In general, it should be feasible to recycle the BOF slag in the production of AAC. However, the foreign elements introduced by the BOF slag can alter the formation and structure of hydrates, including tobermorite, and thus affect the properties of the AAC product, a potential issue that needs to be addressed.

scholarly journals Characteristics of Different Types of Basic Oxygen Furnace Slag Filler and its Influence on Properties of Asphalt Mastic

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4034 ◽  
Author(s):  
Dezhi Kong ◽  
Shaopeng Wu ◽  
Meizhu Chen ◽  
Meiling Zhao ◽  
Benan Shu
Keyword(s):  
Chemical Composition ◽  
Asphalt Mixture ◽  
Basic Oxygen Furnace ◽  
Stiffness Modulus ◽  
Limestone Filler ◽  
Basic Oxygen ◽  
Asphalt Mastic ◽  
Different Types ◽  
Bof Slag ◽  
Basic Oxygen Furnace Slag

The fillers of ordinary and pyrolytic basic oxygen furnace (BOF) slag were selected to investigate the properties of their asphalt mastic. XRF (X-Ray Fluorescence) was used to analyze chemical composition of fillers. Meanwhile, SEM (Scanning Electron Microscope) and AIMS (Aggregate Image Measurement System) were utilized to explore meso-morphology, angularity and sphericity. Penetration, softening point and viscosity of asphalt mastic were discussed, while the rheological properties of asphalt mastic were studied by means of DSR (dynamic shear rheometer) and BBR (bending beam rheometer) tests. The experimental results show that chemical composition of different types of BOF slag is similar. The grinding energy consumption of pyrolytic BOF slag is higher than that of limestone and ordinary BOF slag. It is not recommended that pyrolytic BOF slag filler is produced by grinding process. The micro-texture structure of ordinary BOF slag filler is more abundant and their angularity index is about 15% higher than that of limestone filler. The stiffness modulus and rutting factor of asphalt mastic with ordinary BOF slag filler is higher than that of limestone filler. Meanwhile the incorporation of BOF slag filler will further reduce the low-temperature flow performance of asphalt mastic. The effect of pyrolytic BOF slag filler on the performance of asphalt mastic is less than that of ordinary BOF slag. Ordinary BOF slag filler can effectively improve high temperature anti-rutting stability of asphalt mixture. Ordinary BOF slag has a useful application prospect as filler in asphalt mixture.

scholarly journals Time-Dependent Strength Behavior, Expansion, Microstructural Properties, and Environmental Impact of Basic Oxygen Furnace Slag-Treated Marine-Dredged Clay in South Korea

2021 ◽  
Vol 13 (9) ◽  
pp. 5026
Author(s):  
Gyeong-o Kang ◽  
Jung-goo Kang ◽  
Jin-young Kim ◽  
Young-sang Kim
Keyword(s):  
Particle Size ◽  
Environmental Impact ◽  
South Korea ◽  
Mechanical Characteristics ◽  
Basic Oxygen Furnace ◽  
Microstructural Properties ◽  
Compression Tests ◽  
Basic Oxygen ◽  
Strength Behavior ◽  
Bof Slag

The aim of this study was to investigate the mechanical characteristics, microstructural properties, and environmental impact of basic oxygen furnace (BOF) slag-treated clay in South Korea. Mechanical characteristics were determined via the expansion, vane shear, and unconfined compression tests according to various curing times. Scanning electron microscopy was conducted to analyze microstructural properties. Furthermore, environmental impacts were evaluated by the leaching test and pH measurements. According to the results, at the early curing stage (within 15 h), the free lime (F-CaO) content of the BOF slag is a significant factor for developing the strength of the adopted sample. However, the particle size of the BOF slag influences the increase in the strength at subsequent curing times. It was inferred that the strength behavior of the sample exhibits three phases depending on various incremental strength ratios. The expansion magnitude of the adopted samples is influenced by the F-CaO content and also the particle size of the BOF slag. Regarding the microstructural properties, the presence of reticulation structures in the amorphous gels with intergrowths of rod-like ettringite formation was verified inside the sample. Finally, the pH values and heavy metal leachates of the samples were determined within the compatible ranges of the threshold effect levels in the marine sediments of the marine environment standard of the Republic of Korea.

scholarly journals Simulated Experiment Study of Factors Influencing the Hydration Activity of f-CaO in Basic Oxygen Furnace Slag

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Ruiquan Jia ◽  
Jiaxiang Liu
Keyword(s):  
Solid Solutions ◽  
Volume Expansion ◽  
Basic Oxygen Furnace ◽  
Hydration Reaction ◽  
Basic Oxygen ◽  
Activity Sequence ◽  
Bof Slag ◽  
Iron Phase ◽  
Calcium Iron ◽  
Iron Manganese

The compositions and formation process of f-CaO in BOF slag were revealed and simulated to understand its expansion rules and why its hydration activity is low. BSE showed the compositions of f-CaO, which included calcium iron phase and calcium iron manganese phase, were diverse. The hydration activity sequence was Ca2Fe2O5 and Ca3Fe1.5Mn1.5O8 in tricomponent f-CaO < CaO in tricomponent f-CaO < monocomponent f-CaO; only Ca2Fe2O5 and Ca3Fe1.5Mn1.5O8 were hard to hydrate, and the volume expansion rates of the tricomponent f-CaO varied with different compositions. Inductively, in BOF slag, the hydration activity sequence was solid solutions CaO-FeOx and CaO-FeOx-MnOy in tricomponent f-CaO < CaO in tricomponent f-CaO < monocomponent f-CaO; the volume expansion rates of tricomponent f-CaO changed with different compositions, and CaO-FeOx and CaO-FeOx-MnOy were difficult to hydrate. The reason why solid solutions CaO-FeOx and CaO-FeOx-MnOy were hard to hydrate was that their hydration reaction driving force, which is the absolute value of standard molar reaction Gibbs functions, decreased.

scholarly journals Geotechnical Properties and Microstructure of Lime-Fly Ash-Phosphogypsum-Stabilized Soil

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Tebogo Pilgrene Mashifana ◽  
Felix Ndubisi Okonta ◽  
Freeman Ntuli
Keyword(s):  
Fly Ash ◽  
Expansive Soil ◽  
Basic Oxygen Furnace ◽  
Geotechnical Properties ◽  
Magnesium Silicide ◽  
Engineering Properties ◽  
Basic Oxygen ◽  
Basic Oxygen Furnace Slag ◽  
Phosphogypsum Waste ◽  
Furnace Slag

The use of industrial waste as a potential stabilizer of marginal construction materials is cost effective. Phosphogypsum and fly ash are industrial wastes generated in very large quantities and readily available in South Africa. In order to explore the potential stabilization of vastly abundant expansive soil using larger quantity phosphogypsum waste as a potential modifier, composites with a mixture of lime-fly ash-phosphogypsum-basic oxygen furnace slag were developed. However because of the presence of radionuclide, it was necessary to treat the phosphogypsum waste with mild citric acid. The effect of the acid treatment on the geotechnical properties and microstructure of expansive soil stabilized with phosphogypsum-lime-fly ash-basic oxygen furnace slag (PG-LFA-BOF) paste was evaluated, in comparison with the untreated phosphogypsum. Expansive soil stabilized with acid-treated PG-LFA-BOF paste exhibited better geotechnical properties; in particular, the high strength mobilized was associated primarily with the formation of various calcium magnesium silicide and coating by calcium silicate hydrate and calcium aluminate hydrate. The soil microstructure was improved due to the formation of hydration products. The stabilized expansive soil met the specification for road subgrades and subbase. Stabilization of expansive soils with phosphogypsum, fly ash, and basic oxygen fly ash does not only improve engineering properties of soil but also provides a solution in relation to disposal and environmental pollution challenges.

Basic oxygen furnace slag: Review of current and potential uses

2020 ◽  
Vol 149 ◽  
pp. 106234 ◽  
Author(s):  
Tamlyn Sasha Naidu ◽  
Craig Michael Sheridan ◽  
Lizelle Doreen van Dyk
Keyword(s):  
Basic Oxygen Furnace ◽  
Basic Oxygen ◽  
Basic Oxygen Furnace Slag ◽  
Furnace Slag
Sign in / Sign up

Export Citation Format

Share Document