Steam and Autoclave Treatments on Structure Characteristics of Steel Slag

2011 ◽  
Vol 356-360 ◽  
pp. 1919-1927 ◽  
Author(s):  
Qing Lin Zhao ◽  
Jochen Stark ◽  
Ernst Freyburg ◽  
Ming Kai Zhou
Keyword(s):  
Steel Slag ◽  
Basic Oxygen Furnace ◽  
Free Lime ◽  
Basic Oxygen ◽  
Volume Stability ◽  
Structure Characteristics ◽  
Key Factor ◽  
Electric Arc Furnace Slag ◽  
Basic Oxygen Furnace Slag ◽  
Furnace Slag

Together with the chemical analysis as well as XRD and DTA, effects of steam and autoclave treatments on structure characteristics of basic oxygen furnace slag (BOFS) and electric arc furnace slag (EAFS) are investigated. The results show that steam and autoclave treatments on slag contribute to the conversion of f-CaO and f-MgO to Ca(OH)2 and Mg(OH)2 ,which improve the volume stability of slag by reducing the contents of free lime and periclase, and the autoclave treatment is more effective. Meanwhile, for the utilization of steel slag, the effects on the volume stability by CaO and MgO that were wrapped in eutectic in the crystallite form should be a key factor, besides the contents of f-CaO and coarse periclase crystalline. The thermal reactivity of slag treated by steam and autoclave increased, especially the reactivity of elemental iron and wuestite. The reactivity of EAFS increased more significantly at high temperature due to its higher content of iron.

scholarly journals Fluid Permeability of Ground Steel Slag-Blended Composites Evaluated by Pore Structure

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Jin Yang ◽  
Jian Jiang ◽  
Ying Su ◽  
Xingyang He ◽  
Yingbin Wang ◽  
...  
Keyword(s):  
Pore Structure ◽  
Pore Radius ◽  
Steel Slag ◽  
Basic Oxygen Furnace ◽  
Throat Radius ◽  
Basic Oxygen ◽  
Fluid Permeability ◽  
Gel Porosity ◽  
Basic Oxygen Furnace Slag ◽  
Furnace Slag

The resource utilization of steel slag has attracted wide attention. In the present work, the pore structure of cement paste with and without ground basic oxygen furnace slag (BOFS) up to 180 days was investigated by mercury intrusion porosimetry. Permeability was evaluated from the tested pore structure. Results indicate that the porosity, critical pore radius, pore-throat radius, and permeability are increased with the BOFS content and levels off after 28 days. Lower gel porosity and higher coarse capillary porosity were observed in BOFS-blended composites. The calculated permeability (around 0.30–7.49 × 10−19 m2) based on the pore structure agrees well with the range of reported experimental measurements. Well-correlated linear and power-law relationship was noticed between permeability and porosity and characteristic pore radius, respectively.

Achieving stable steelmaking basic oxygen furnace slag through treatment by self-disintegration high pressure process

2021 ◽  
Vol 118 (2) ◽  
pp. 207
Author(s):  
Ben Peng ◽  
Yue-Dong Wu ◽  
Chang-Sheng Yue ◽  
Yu-Xiang Li
Keyword(s):  
High Pressure ◽  
Treatment Time ◽  
Steel Slag ◽  
Basic Oxygen Furnace ◽  
National Standards ◽  
Hydration Reaction ◽  
Thermodynamic Evaluation ◽  
Basic Oxygen ◽  
Basic Oxygen Furnace Slag ◽  
Furnace Slag

The basic oxygen furnace slag generated during steelmaking can be reused as aggregates in civil engineering because of its chemical composition and technological properties. However, the utilization of steel slag in practical applications is quite low due to its low volume stability. In this work, highly stable slag is obtained by the environmental-friendly self-disintegration high pressure (SDHP) process. In this method, the molten slag is initially crushed to form numerous small bulks. Subsequently, the slag bulks are treated by the self-disintegration process at a high pressure to obtain the highly stable steel slag. Thermodynamic evaluation and experimental investigation reveal that high pressure of steam promotes the hydration reaction. At a pressure of 0.2 MPa, the free lime (f-CaO) content and immersion expansion rate of the steel slag treated by this method are reduced to 1.5% and 0.9%, respectively. Both of these values satisfy the requirements specified in the national standards (GB/T 25029-2010 and GB/T 20491-2006). Moreover, the treatment time is reduced to 1.5 h, which is far lower than the treatment times required for traditional methods.

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

scholarly journals Feasibility and Characterization Mortar Blended with High-Amount Basic Oxygen Furnace Slag

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 6 ◽  
Author(s):  
Wei-Ting Lin ◽  
Chia-Jung Tsai ◽  
Jie Chen ◽  
Weidong Liu
Keyword(s):  
Steel Industry ◽  
Setting Time ◽  
Basic Oxygen Furnace ◽  
Cementitious Material ◽  
Partial Replacement ◽  
Supplementary Cementitious Material ◽  
Basic Oxygen ◽  
Basic Oxygen Furnace Slag ◽  
Furnace Slag ◽  
Weight Proportion

Basic oxygen furnace slag (BOFS) was ground to three levels of fineness as a replacement for cement at weight proportions of 10, 30, 50, and 70 wt.%. Fineness and weight proportion were shown to have significant effects on the flowability and setting time of the mortars. The expansion of BOFS mortars increased with an increase in the proportion of cement replaced, thereby exacerbating the effects of cracking. Optimal mechanical properties were achieved when 10 wt.% of the cement was replaced using BOFS with fineness of 10,000 cm2/g. The compressive strength of BOFS mortar is similar to that of ordinary Portland mortar, which makes BOFS suitable for the partial replacement of cement as a supplementary cementitious material. Scanning electron microscopy results revealed that the reaction of CaO with H2O results in the formation of C–S–H colloids, whereas the reaction of SiO2 with Al2O3 produces C–A–S–H colloids. The use of BOFS as a partial replacement for Portland cement could make a tremendous contribution to the steel industry and help to lower CO2 emissions.

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