scholarly journals Effect of Basicity and Al2O3 on Viscosity of Blast Furnace Slag and Thermodynamic Analysis

2021 ◽  
Author(s):  
Jian Zhang ◽  
Zhengjian Liu ◽  
Jianliang Zhang ◽  
Cui Wang ◽  
Hengbao Ma ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Blast Furnace ◽  
Constant Temperature ◽  
Slag Basicity ◽  
Al2o3 Content ◽  
Wave Number ◽  
Slag Viscosity ◽  
Slag Structure ◽  
Slag Temperature

With the increased use of laterite nickel ore, the impact of high Al2O3 slag on blast furnace smelting has gradually increased. In this paper, the effects of slag basicity and Al2O3 content on slag viscosity and enthalpy change under constant temperature conditions was investigated. The changes in slag structure were analyzed by activation energy and Fourier Transform Infrared (FT-IR) spectroscopy. The relationship between slag components and slag temperature and viscosity when slag heat is reduced was investigated. The results showed that the viscosity first slightly decreased and then significantly increased with increasing basicity at constant temperature. With the addition of Al2O3 content, the viscosity of the slag increases. The activation energy increases with increasing slag basicity and Al2O3. With increasing basicity, the [SiO4]4- tetrahedral unit trough depth becomes shallow, the [AlO4]5- asymmetric stretching band migrates to lower wave numbers, and the slag structure depolymerizes. With the increase of Al2O3 content, the trough of [SiO4]4- tetrahedra deepens and the center of the symmetric stretching band moves to a higher wave number. The [AlO4]5- asymmetric stretching band becomes obvious, indicating the complexity of the slag structure. When the heat decreases, the slag temperature increases as the basicity increases, and the slag thermal stability is better at the basicity of 0.95-1.05. As the Al2O3 content increases, the thermal stability of the slag becomes worse.

Calculation Model of Mass Action Concentrations for CaO-Al2O3-SiO2 Slag System

2012 ◽  
Vol 217-219 ◽  
pp. 39-42
Author(s):  
Hong Ming Wang ◽  
Gui Rong Li ◽  
Xiang Zhu ◽  
Yu Tao Zhao
Keyword(s):  
Slag System ◽  
Calculation Model ◽  
Slag Basicity ◽  
Mass Action ◽  
Al2o3 Content ◽  
Coexistence Theory ◽  
Slag Structure

According to the coexistence theory of melted slag structure, a calculation model of mass action concentrations for CaO-Al2O3-SiO2 slag system has been established, by which the mass action concentrations of all structure units in CaO-SiO2-Al2O3 systems are calculated. The effects of Al2O3 content and slag basicity on the mass action concentrations are investigated. The results indicate that both basicity and the content of Al2O3 have remarkable effects on mass action concentrations of CaO, 2CaO•SiO2, CaO•SiO2, CaO•Al2O3 and 2CaO•SiO2•Al2O3, etc. Furthermore, the effects of Al2O3 content on mass action concentrations are relevant with slag basicity. The basicity has more influences on mass action concentrations of CaO, CaO•SiO2, 2CaO•SiO2 and 3CaO•SiO2, whereas the basicity has little effect on mass action concentrations of other structure units in CaO-SiO2-Al2O3 system.

scholarly journals Thermodynamic Properties, Viscosity, and Structure of CaO–SiO2–MgO–Al2O3–TiO2–Based Slag

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 124
Author(s):  
Jinle Fang ◽  
Zhuogang Pang ◽  
Xiangdong Xing ◽  
Runsheng Xu
Keyword(s):  
Activation Energy ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Heat Supply ◽  
Enthalpy Change ◽  
Tio2 Content ◽  
Constant Heat ◽  
Slag Structure ◽  
Tio2 Addition ◽  
Slag Temperature

The effect of TiO2 and the MgO/Al2O3 ratio on the viscosity, heat capacity, and enthalpy change of CaO–SiO2–Al2O3–MgO–TiO2 slag at constant heat input was studied. The variation of slag structure was analyzed by the calculation of activation energy and FTIR spectrum measurements. The results showed that the heat capacity and enthalpy change of the slag decreased with the increase of TiO2 content. Under constant heat supply, the fluctuations in slag temperature were relatively apparent, and the temperature of slag increased as the TiO2 content increased. The viscosity of slag decreased due to the increase in slag temperature. Increasing the MgO/Al2O3 ratio could decrease the temperature and viscosity of slag. The effect of increasing the MgO/Al2O3 ratio on the viscosity was more pronounced than the decreasing temperature caused by increasing the MgO/Al2O3 ratio. The apparent activation energy decreased with increasing TiO2 content and MgO/Al2O3 ratio. The Ti–O bonds formed with TiO2 addition, and the Ti–O bonds were weaker than Si–O bonds, which resulted in the decrease in heat capacity and viscosity of slag.

scholarly journals Analysis of possible ways to reduce sulfur content in pig iron

2021 ◽  
Vol 63 (11-12) ◽  
pp. 878-882
Author(s):  
S. V. Myasoedov ◽  
S. V. Filatov ◽  
V. V. Panteleev ◽  
V. S. Listopadov ◽  
S. A. Zagainov
Keyword(s):  
Blast Furnace ◽  
Cast Iron ◽  
Sulfur Content ◽  
Sulfur Removal ◽  
Slag Basicity ◽  
Slag Viscosity ◽  
Pig Iron ◽  
Blast Furnace Smelting ◽  
Coal Fuel ◽  
Slag Yield

One of the ways to increase the energy efficiency and intensity of blast furnace smelting, especially when using pulverized coal fuel, is to increase the hot strength of coke. In the conditions of OJSC NLMK, an oil additive was introduced into the coal charge to improve the coke quality. At the same time, sulfur content in the coke increases, and, consequently, sulfur content in the cast iron increases as well. In this regard, the task of finding ways to improve the desulfurization of cast iron in blast furnace becomes urgent. The main factors determining the desulfurization of cast iron are slag basicity, content of MgO oxide in it, temperature of the smelting products, and the slag viscosity. The purpose of this work was to compare the efficiency of sulfur removal by increasing the slag basicity and MgO content. On the basis of wellknown equations, an algorithm was developed that allows the problem to be solved. It was established that an increase in MgO content in the slag promotes desulfurization of cast iron to a greater extent than a basicity increase. In addition, an increase in MgO content by 1 % is accompanied by an increase in slag yield by 3.0 – 3.5 kg/t of cast iron. At the same time, an increase in basicity by 0.01 leads to an increase in the slag yield by 4 – 5 kg/t of pig iron. Consequently, reducing the sulfur content in pig iron by increasing the slag basicity requires less heat. In terms of the specific consumption of coke, difference in heat demand is 0.4 – 0.5 kg/t of pig iron. It is shown that with an increase in MgO content in the slag, the slag viscosity at a temperature of 1450 °C increases to a lesser extent than with an increase in basicity.

scholarly journals Influence of Al2O3 Content on the Melting and Fluidity of Blast Furnace Type Slag with Low TiO2 Content

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Hao Liu ◽  
Yuelin Qin ◽  
Yanhua Yang ◽  
Qianying Zhang ◽  
Nengyun Deng
Keyword(s):  
Blast Furnace ◽  
Viscous Flow ◽  
Slag System ◽  
Al2o3 Content ◽  
Slag Viscosity ◽  
Flow Activation Energy ◽  
Flow Units ◽  
Precipitated Phase ◽  
Flow Activation ◽  
Furnace Slag

The increasing usage of iron ores with high Al2O3 content significantly increases the amount of Al2O3 in blast furnace slag and consequently affects its performance. This work uses slag sampled on site to study the effects of changes in Al2O3 content on the fluidity of the CaO–SiO2–Al2O3–MgO–TiO2 slag system that is characterized by high Al2O3 and low TiO2 contents, as well as on the phase transition law during the cooling process. Slag viscosity exhibits a rising trend with an increase in Al2O3 content, and Al2O3 in the tested slag is alkaline. The viscous flow activation energy of molten slag rises from 157 kJ/mol to 172 kJ/mol with an increase in Al2O3 content, and the viscous flow units in the slag become large and complicated. When slag is cooled, the main precipitated phase is melilitite. Spinel, perovskite, and olivine are also observed. The crystallization amount of the melilitite phase decreases constantly with an increase in Al2O3 content.

Application in the Experimental Data Analysis of the Slag Viscosity with Minitab Software

2013 ◽  
Vol 753-755 ◽  
pp. 1857-1861
Author(s):  
Shu Qing Zhang ◽  
Xiu Ling Lv ◽  
Li Hong Zhang ◽  
Na Hui Zhang
Keyword(s):  
Experimental Data ◽  
Blast Furnace ◽  
Data Analysis ◽  
Blast Furnace Slag ◽  
Slag Basicity ◽  
Slag Viscosity ◽  
Chemical Compositions ◽  
Single Factor ◽  
Experimental Data Analysis ◽  
Furnace Slag

The single factor variance of viscosity experimental data of blast furnace slag was calculated by Minitab software. The influence of slag basicity and chemical compositions on the slag viscosity was obtained. The results show that there have insignificant effects on the slag viscosity when the slag basicity is over than 1.02, MgO content is less than 11.95% or TiO2 content is less than 12.57%. While the slag basicity can be influenced significantly with the slag basicity less than 1.02, MgO content over than 13.95% and TiO2 content over 13.57%. The Al2O3 content of the slag should be less than 12.75%.

scholarly journals Roles of MgO and Al2O3 on the Viscous and Structural Behavior of Blast Furnace Primary Slag, Part 1: C/S = 1.3 Containing TiO2

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 866 ◽  
Author(s):  
Tingle Li ◽  
Changyu Sun ◽  
Sunny Song ◽  
Qi Wang
Keyword(s):  
Blast Furnace ◽  
Network Structure ◽  
Equilibrium Phase ◽  
Phase Region ◽  
Structure Characterization ◽  
Al2o3 Content ◽  
Slag Viscosity ◽  
Stable Operation ◽  
The Difference ◽  
Cylinder Method

This research provides fundamental insight into the roles of MgO and Al2O3 on the viscous and structural behaviors of CaO−SiO2−MgO−Al2O3−10 mass% TiO2−5 mass% FeO (CaO/SiO2 = 1.3) system primary blast furnace slag. The slag viscosity is measured by the rotating cylinder method, which is essential to the efficient and stable operation of a blast furnace. The network structure characterization of the quenched vitreous samples was conducted using Fourier Transformation Infrared (FTIR) and Raman spectroscopy. Unusual viscous behaviors (that the slag viscosity and the activation energy decrease or increase with increasing MgO or Al2O3 content) were observed, corresponding to changes in the network structure certified by FTIR and Raman analyses. It seems that the addition of MgO and Al2O3 prefers to modify the Si−O and Ti−O network in the present slag. When the slag composition reaches 10% MgO and 12% Al2O3, unexpected viscous behaviors (that MgO increases viscosity and Al2O3 decreases viscosity) are discovered. The roles of MgO and Al2O3 could be interpreted by changes in the arrangement structure of ions in liquid, corresponding to changes in the primary equilibrium phase region determined in phase diagrams and variation in the difference between the experimental and liquidus temperature, respectively.

Analysis of hot metal desulfurization methods efficiency during titanomagnetite processing

2020 ◽  
Vol 76 (6) ◽  
pp. 543-549
Author(s):  
V. V. Panteleev ◽  
K. B. Pykhteeva ◽  
M. V. Polovets ◽  
K. V. Mironov ◽  
S. A. Zagainov
Keyword(s):  
Blast Furnace ◽  
Data Analysis ◽  
Sulfur Content ◽  
Slag Basicity ◽  
Slag Viscosity ◽  
Blast Furnaces ◽  
Hot Metal ◽  
Blast Furnace Smelting ◽  
Low Sulfur ◽  
Hot Metal Desulfurization

To make high-quality steel, it is necessary to ensure low sulfur content in the hot metal entering a steelmaking shop. The task to obtain low sulfur metal can be solved either during blast furnace smelting or its ladle desulfurization immediately after tapping out of blast furnace. Under conditions of JSC EVRAZ NTMK, the ladle desulfurization of vanadium hot metal is not applied, since it leads to a loss of vanadium. Is explained by the fat, that calcium oxide forms with V2O5 a strong calcium vanadate (3СаО·V2O5), which makes the process of vanadium recovery during further slag processing more complicated. Therefore the ladle desulfurization is accomplished after devanadation of hot metal. After the devanadation the semi-product has ions of oxygen, which makes it impossible to arrange an effective desulfurization and males it necessary to smelt the hot metal with limited sulfur content. The factors, effecting the process of hot metal desulfurization in a blast furnace, including slag basicity, MgO content in it, temperature of smelting products and slag viscosity, are presented. Dependence of distribution coefficient of sulfur on slag basicity has been shown. Research goal is pig iron desulphurization efficiency estimation by means of MgO increasing in slag. Data analysis findings about smelting products composition over 500 tappings for each of two investigated JSC EVRAZ NTMK blast furnaces have been reported. The aim of the study was comparison of hot metal desulphurization efficiency due to both slag basicity increase and MgO increase in slag. Results of data analysis on smelting products composition of over 500 heats for each of two investigated JSC EVRAZ NTMK blast furnaces have been presented. It was established that a sulfur content decrease in hot metal is achieved more effectively by MgO increase in slag. It has been shown that MgO has better desulfurizing properties, and with an increase of its content in the blast furnace slag, the overall technology for running the blast furnace process improves. It was recommended to increase the consumption of materials containing MgO while maintaining basicity at a constant level. Such a technology will allow to decrease sulfur content in hot metal, as well as will result in the process stabilization providing other conditions being equal.

Study on Viscosity of Titania Bearing Blast Furnace Slag

2011 ◽  
Vol 467-469 ◽  
pp. 1742-1745 ◽  
Author(s):  
Jin Zhu Zhang ◽  
Ling Wen ◽  
Ming Hua Long ◽  
Bi Neng Yang
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Orthogonal Design ◽  
Al2o3 Content ◽  
Slag Viscosity ◽  
Iron And Steel ◽  
Analytical Reagent ◽  
Bf Slag ◽  
Furnace Slag

The viscosity of blast furnace slag which was taken from Shuicheng Iron and Steel Group Co. Limited was experimentally measured by column whirling method using the ND-II slag viscosity tester. By adding analytical reagent CaO, SiO2, Al2O3, MgO and TiO2 in accordance with orthogonal design, the contents of compositions in slag were adjusted in CaO/SiO2=1.16-1.24, 14.06-17.06mass%Al2O3, 5-7mass%TiO2, 8.96-9.96mass%MgO. The results showed that the viscosity of BF slag decreased with increasing TiO2; when the Al2O3 content in the slag was 14.06%, the viscosity of BF slag had a lowest value, a highest value had for 15.56% Al2O3 content, and a lower value for 17.06% Al2O3 content. There is no significant effect on the viscosity by both the magnesia and the binary basicity.

scholarly journals Desulfurization Ability of Blast Furnace Slag Containing High Al2O3 at 1773 K

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 910
Author(s):  
Yongchun Guo ◽  
Fengman Shen ◽  
Haiyan Zheng ◽  
Shuo Wang ◽  
Xin Jiang ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Iron Ore ◽  
Al2o3 Content ◽  
High Alumina ◽  
Free Oxygen ◽  
Oxygen Ions ◽  
Slag Structure ◽  
Ft Ir ◽  
Furnace Slag

With the consumption of high-quality iron ore resources, the grade of iron ore raw used in the iron making process has gradually decreased. The high aluminum raw materials has led to an increase in the Al2O3 content in the blast furnace slag, which has affected the normal operation of the blast furnace. The activity of the components involved in the desulfurization reaction is an important factor affecting the desulfurization process. In this paper, the effects of B(w(CaO)/w(SiO2)) and w(MgO)/w(Al2O3) on the desulfurization ability of a CaO-SiO2-MgO-Al2O3 quaternary blast furnace slag system were studied by using a double-layer graphite crucible to simulate the process of molten iron dropping through the slag at 1773 K. The desulfurization reaction mechanism of high alumina blast furnace slag is explained from the aspects of slag structure and component activity, which provides a theoretical basis for the reasonable selection of a slag making system under the condition of a high alumina content. The effects of different B and w(MgO)/w(Al2O3) on the slag structure 2343 analyzed by Fourier transform infrared spectroscopy (FT-IR). The results show that when w(MgO)/w(Al2O3) = 0.50 and w(Al2O3) = 20%, the desulfurization ability and MgO activity of slag increased with the increase of B; when w(Al2O3) = 20% and B = 1.30, the desulfurization ability and MgO activity of the slag increased with the increase of w(MgO)/w(Al2O3). The FT-IR analysis showed that with the increase of B or w(MgO)/w(Al2O3), the dissociated free oxygen ions (O2-) in the slag increased, and the dissociated free oxygen ions (O2-) interacted with the bridging oxygen (O0) of silicate, which made the complex Si-O structure in the slag gradually depolymerize and increase the desulfurization ability.

scholarly journals Effect of Fe/SiO2 Ratio and Fe2O3 on the Viscosity and Slag Structure of Copper-Smelting Slags

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 24
Author(s):  
Baoren Wang ◽  
Hongying Yang ◽  
Zhenan Jin ◽  
Zhijian Liu ◽  
Mingjun Zou
Keyword(s):  
Activation Energy ◽  
Viscous Flow ◽  
Effective Means ◽  
Slag System ◽  
Copper Smelting ◽  
Smelting Process ◽  
Slag Viscosity ◽  
Fe2o3 Content ◽  
Slag Structure ◽  
Secondary Copper Smelting

Secondary copper smelting is an effective means of treating waste resources. During the smelting process, the viscous behavior of the smelting slags is essential for smooth operation. Therefore, the effects of Fe/SiO2 ratio and Fe2O3 contents on the viscous behavior of the FeO−Fe2O3−SiO2−8 wt%CaO−3 wt%MgO−3 wt%Al2O3 slag system were investigated. The slag viscosity and activation energy for viscous flow decrease with increasing Fe/SiO2 from 0.8 to 1.2, and increase as the Fe2O3 content increases from 4 wt% to 16 wt% at Fe/SiO2 ratio of 1.2. However, under the conditions of Fe/SiO2 of 0.8 and 1.0, the viscosity and activation energy for viscous flow show a minimum value at Fe2O3 content of 12 wt%. Fe2O3 exhibits amphoteric properties. In addition, the increase in Fe2O3 content raises the breaking temperature of the slag, while the Fe/SiO2 ratio has the opposite effect. Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy show that increases in Fe/SiO2 ratio lead to simplification of the silicate network structure, while increases in Fe2O3 content improves the formability of the network. This study provides theoretical support for the related research and application of secondary copper smelting.

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