scholarly journals Evaluating the Effect of MgO/Al2O3 Ratio on Thermal Behaviors and Structures of Blast Furnace Slag with Low Carbon Consumption

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1386
Author(s):  
Wenlong Zhan ◽  
Yi Liu ◽  
Tengfei Shao ◽  
Xiao Han ◽  
Qinghai Pang ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Complex Structure ◽  
Temperature Stability ◽  
Slag System ◽  
Industrial Test ◽  
Operating Conditions ◽  
Low Carbon ◽  
Ft Ir ◽  
Furnace Slag

In order to clarify the effect of the MgO/Al2O3 ratio on the fluidity of a low-alumina blast furnace slag system, the influence law of slag fluidity with different MgO/Al2O3 ratios was studied based on the composition of blast furnace slag through a viscosity experiment and themodynamic software. By studying the effect of the MgO/Al2O3 ratio on the activation energy of viscous flow of slag combined with FT-IR, the effect of the MgO/Al2O3 ratio on the thermal-stability of low-aluminum slag was interpreted from the microstructure level. Results indicated that the viscosity and the melting temperature of slag both showed a gradual downward trend due to the increase of the MgO/Al2O3 ratio. Besides, the temperature stability of the low aluminum slag became more stable due to the depolymerization of the complex structure of slag. Considering the actual operating conditions of blast furnace, the MgO/Al2O3 ratio of slag was suggested to be controlled to 0.60 and the basicity to be no higher than 1.20 under the conditions of this investigation. Industrial test results showed that the coke rate could be saved as 3.49 kg/t when the MgO/Al2O3 ratio decreased from 0.70 to 0.58.

The Influence of the Properties of the Material Used for Obtaining Geopolymers on Their Structure and Compressive Strength

2017 ◽  
Vol 68 (6) ◽  
pp. 1182-1187
Author(s):  
Ilenuta Severin ◽  
Maria Vlad
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Wheat Straw ◽  
Red Mud ◽  
Blast Furnace Slag ◽  
Complex Structure ◽  
Point Of View ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag ◽  
Straw Ash

This article presents the influence of the properties of the materials in the geopolymeric mixture, ground granulated blast furnace slag (GGBFS) + wheat straw ash (WSA) + uncalcined red mud (RMu), and ground granulated blast furnace slag + wheat straw ash + calcined red mud (RMc), over the microstructure and mechanical properties of the synthesised geopolymers. The activation solutions used were a NaOH solution with 8M concentration, and a solution realised from 50%wt NaOH and 50%wt Na2SiO3. The samples were analysed: from the microstructural point of view through SEM microscopy; the chemical composition was determined through EDX analysis; and the compressive strength tests was done for samples tested at 7 and 28 days, respectively. The SEM micrographies of the geopolymers have highlighted a complex structure and an variable compressive strength. Compressive strength varied from 24 MPa in the case of the same recipe obtained from 70% of GGBFS + 25% WSA +5% RMu, alkaline activated with NaOH 8M (7 days testing) to 85 MPa in the case of the recipe but replacing RMu with RMc with calcined red mud, alkaline activated with the 50%wt NaOH and 50%wt Na2SiO3 solution (28 days testing). This variation in the sense of the rise in compressive strength can be attributed to the difference in reactivity of the materials used in the recipes, the curing period, the geopolymers structure, and the presence of a lower or higher rate of pores, as well as the alkalinity and the nature of the activation solutions used.

scholarly journals Prediction of the properties of blast furnace slag in modern conditions of blast furnaces of Ukraine

2018 ◽  
pp. 118-136
Author(s):  
D.N. Togobitskaya ◽  
A.I. Belkova ◽  
D.A. Stepanenko ◽  
N.A. Tsyupa ◽  
Yu.M. Likhachev
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Rapid Assessment ◽  
Operating Conditions ◽  
Integral Parameter ◽  
Blast Furnaces ◽  
Magnesia Content ◽  
The Individual ◽  
Management Recommendations ◽  
Furnace Slag

The aim of the work is the development of models for predicting the properties of final blast-furnace slags for the rapid assessment of the slag regime and the development of sound management recommendations when using various additives in the operating conditions of blast furnaces in Ukraine. A two-stage approach to calculating the properties of blast-furnace slag is proposed: according to the model of a “homogeneous” melt and taking into account its heterogeneity. A predictive model has been developed for calculating the viscosity of a «homogeneous» slag by including the integral parameter of the slag melt parameter e in the model structure, which takes into account the individual effect on the viscosity of each component of the slag composition. The current production data of the chemical composition of the final slag shows the effect of the magnesia content, alkaline compounds, basicity, Al2O3/MgO ratio on the calculated viscosity of the slags. For various operating conditions of blast furnaces, it has been shown that, due to incomplete combustion of coke and pulverized coal, the viscosity of slags increases by 1.5–2 times and their melting temperatures by 30–500C. Comparative analysis of the calculated properties of slag for different operating conditions of 3 furnaces in Ukraine confirms the appropriateness of using a complex of predictive models for the rapid assessment of the technological properties of slag, which makes it possible to choose a rational slag mode in modern conditions of blast smelting.

scholarly journals Comparative Study on Chloride Binding Capacity of Cement-Fly Ash System and Cement-Ground Granulated Blast Furnace Slag System with Diethanol-Isopropanolamine

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4103
Author(s):  
Huaqing Liu ◽  
Yan Zhang ◽  
Jialong Liu ◽  
Zixia Feng ◽  
Sen Kong
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Binding Capacity ◽  
Slag System ◽  
Chloride Binding ◽  
Chemical Binding ◽  
Granulated Blast Furnace Slag ◽  
Steel Bar ◽  
Furnace Slag

Steel bar corrosion caused by chloride was one of the main forms of concrete deterioration. The promotion of chloride binding capacity of cementitious materials would hinder the chloride transport to the surface of steel bar, thereby alleviating the corrosion and mitigating the deterioration. A comparative study on binding capacity of chloride in cement-fly ash system (C-FA) and cement-ground granulated blast furnace slag system (C-GGBS) with diethanol-isopropanolamine (DEIPA) was investigated in this study. Chloride ions was introduced by adding NaCl in paste, and the chloride binding capacity of the paste samples at 7 d and 60 d was examined. The hydration process was discussed via the testing of hydration heat and compressive strength. The hydrates in hardened paste was characterized by X-ray Diffractometry (XRD), Thermo Gravimetric Analysis (TGA), and Scanning Electron Microscope (SEM). The effect of DEIPA on dissolution of aluminate phase and compressive strength was discussed as well. These results showed that DEIPA could facilitate the hydration of C-FA and C-GGBS system, and the promotion effect was higher in C-FA than that in C-GGBS. DEIPA also increased the binding capacity of chloride in C-FA and C-GGBS systems. One reason was the increased chemical binding, because DEIPA facilitated the dissolution of aluminate to benefit the formation of Friedel’s salt. Other reasons were the increased physical binding and migration resistance. By contrast, DEIPA presented greater ability to increase chloride binding capacity in C-FA system, because DEIPA showed stronger ability to expedite the dissolution of aluminate of FA than that of GGBS, which benefited the formation of FS, thereby promoting the chemical binding. Such results would give deep insight into using DEIPA as an additive in cement-based materials.

scholarly journals Influence of B2O3and Basicity on Viscosity and Structure of Medium Titanium Bearing Blast Furnace Slag

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Lingtao Bian ◽  
Yanhong Gao
Keyword(s):  
Blast Furnace ◽  
Network Structure ◽  
Blast Furnace Slag ◽  
Slag System ◽  
Break Point ◽  
Slag Viscosity ◽  
X Ray Diffraction ◽  
Structure Variation ◽  
Point Temperature ◽  
Furnace Slag

The effects of B2O3and basicity (CaO/SiO2) on the viscous behavior and structure of medium titanium bearing blast furnace slag (MTBBFS) were investigated. High temperature viscosimeter was applied to measure the viscosities of CaO-SiO2-MgO-TiO2-Al2O3-B2O3slag system and X-ray diffraction (XRD), NBO/T ratio, and structure parameterQwere employed to analyze its network structure. The results showed that the viscosity decreased and break point temperature increased with increasing basicity to 1.20. However B2O3addition gave rise to a decrease in slag viscosity and break point temperature inspite of basicity. The more B2O3content leads to the more pronounced variation, especially for the slag with larger basicity. The conventional NBO/T formula was revised to predict the structure variation of relatively complicated medium Ti bearing slag based on the work of Yanhong Gao and other researchers. The increase of B2O3content in slag made parameterQturn fromQ2toQ1, suggesting that network structure became simpler. It was also noticed that the addition of B2O3could suppress the formation of perovskite.

Investigation on Blending CFB Ash with Blast Furnace Slag as Replacement for Portland Cement Used in Concrete Binders

2013 ◽  
Vol 723 ◽  
pp. 623-629 ◽  
Author(s):  
Guan Yu Chen ◽  
Wei Hsing Huang
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Petroleum Coke ◽  
Blast Furnace Slag ◽  
Circulating Fluidized Bed ◽  
Slag System ◽  
Ash Content ◽  
Chemical Compositions ◽  
Volume Stability ◽  
Furnace Slag

Circulating Fluidized Bed (CFB) Boiler is a means of energy-generating process by burning petroleum coke. In order to avoid blazed petroleum coke with high sulfur content from emitting overdosed sulfur dioxide, limestone is introduced in the boiler for desulfuration. The residue collected from the boiler is called CFB ash. In accordance with different boiler position, CFB ashes can be classified as fly ash and bed ash, and both have similar chemical compositions, with high contents of gypsum and calcium oxide. In this study, CFB ash (fly ash) is mixed with blast furnace slag (BFS) as a substitute for cement in making concrete. It is intended that CFB ashes can be used in concrete and a method for proportioning CFB ash in concrete can be developed. The results show that CFB ash can react with cement to produce hydration products such as Ca(OH)2, and bring the activation of blast furnace slag. The paste strength could be low at later ages, if the CFB ash content is too low. Whereas, if the CFB ash content is over 30%, the paste strength will be low at the early age. Therefore, it is concluded that the cement-granulated blast furnace slag system will show best performance at the CFB ash content between 18% and 22%. In autoclave soundness test shows the CFB ash of the high f-CaO content is easy reaction in the water, and also did not negatively affect the quality of the volume stability.

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