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 ◽  
...  

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.

2021 ◽  
Vol 118 (5) ◽  
pp. 515
Author(s):  
Xinguang Hu ◽  
Fengman Shen ◽  
Haiyan Zheng ◽  
Yongchun Guo ◽  
Xin Jiang ◽  
...  

With the shortage of high-quality iron ore resources, more and more attention has been paid to the blast furnace (BF) smelting of Al2O3-rich iron ore in recent years. Thus, investigation on the thermodynamics property of Al2O3-rich blast furnace slag was inevitable in order to produce high quality hot metal with low cost. In this paper, based on the determination of Al2O3 activity by reference slag method at 1873 K in previous study, the effect of the mechanism of slag structure property on Al2O3 activity in CaO-SiO2-MgO-Al2O3 system was discussed by Raman spectra analysis. It was found that the [AlO4] structure was polymerized and [SiO4] structure was depolymerized with the Al2O3 content increasing from 10 wt.% to 18 wt.%, which caused the Al2O3 activity increased.


2001 ◽  
Vol 44 (11-12) ◽  
pp. 69-75 ◽  
Author(s):  
B. Grüneberg ◽  
J. Kern

The suitability of iron-ore and blast furnace slag for subsurface flow (SSF) constructed wetlands was studied over a period of four months. Dairy farm wastewater (TP 45 mg l-1) was percolated through buckets planted with reed (volume 9.1 l; hydraulic load 15 l m-2d-1). One group of buckets was kept under aerobic conditions and the other group under anaerobic conditions, monitored by continuous redox potential measurements. Even at high mass loading rates of 0.65 g P m-1d-1 the slag provided 98% removal efficiency and showed no decrease in performance with time. However, phosphorus fractionation data indicate that the high phosphorus retention capacity under aerobic conditions is to a great extent attributable to unstable sorption onto calcium compounds (NH4Cl-P). Phosphorus sorption of both the slag (200 μg P g-1) and the iron-ore (140 μg P g-1) was promoted by predominantly anaerobic conditions due to continuous formation of amorphous ferrous hydroxides. None of the substrates had adverse affects on reed growth.


Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 784
Author(s):  
Fengman Shen ◽  
Xinguang Hu ◽  
Haiyan Zheng ◽  
Xin Jiang ◽  
Qiangjian Gao ◽  
...  

With the gradual depletion of high-quality iron-ore resources, ironmaking blast furnaces have gradually shifted to using high-content Al2O3 iron ore. Under this condition, the addition of MgO in the slag is adopted to alleviate operation problems caused by the high content of Al2O3. However, the proper value of the MgO/Al2O3 ratio for blast-furnace slag systems (Al2O3 = 8–25%) is not systematically studied. In this paper, we discuss the proper MgO/Al2O3 ratio on the basis of blast-furnace slag systems under different Al2O3 contents. On the basis of thermodynamics and phase-diagram analysis, it could be concluded that: (1) the MgO/Al2O3 ratio is not limited when Al2O3 in slag is less than 14%, (2) the MgO/Al2O3 ratio is required to be in the range of 0.40–0.50 when Al2O3 in the slag is 15–17%, and (3) the MgO/Al2O3 ratio should be 0.45–0.55 when Al2O3 in the slag is larger than 18%. The proper MgO/Al2O3 ratio value has been established in various industries, and it has achieved significant economic and social benefits.


2010 ◽  
Vol 160-162 ◽  
pp. 1253-1256
Author(s):  
Zhi Xia Zhang ◽  
Hai Sheng Yin

A new concept, “Plus Calcium Oxide Grade”, was put forward, which is the very mass percentage of iron element when Calcium Oxide addition fulfills the need of the basicity of the blast furnace slag. The “Plus Calcium Oxide Grade” and “Minus Calcium Oxide Grade” of iron ore, iron concentrate, sinter and pellet was calculated, analyzed and also compared. The results showed that: the Plus Calcium Oxide Grade can reflect the smelting value more objectively and reasonably, while the basic grade and “Minus Calcium Oxide Grade” can not. So it is suggested that the concept of “Plus Calcium Oxide Grade” can be brought into the iron ore dealing and using, and also into the area of iron concentrate, sinter, pellet and furnace mixture.


2016 ◽  
Vol 79 ◽  
pp. 257-264 ◽  
Author(s):  
Bingqiang Han ◽  
Peng Wang ◽  
Changming Ke ◽  
Wen Yan ◽  
Yaowu Wei ◽  
...  

2015 ◽  
Vol 1094 ◽  
pp. 352-359 ◽  
Author(s):  
Jie Li ◽  
Kai Zhao ◽  
Yu Zhu Zhang ◽  
Wei Xing Liu ◽  
Ai Min Yang

The direct fibrillation of blast furnace slag can solve these problems, such as having not been recycled of sensible heat, the consumption of water resources, environmental pollution and the low additional value of product, which are caused by the traditional water quenching method. The modification is the key problem of fiber forming. The thesis mainly aims at the study of viscosity of slag, the ability of crystallization and mineral phase structure after the modified process of blast furnace slag and confined the relevance of the three to optimize the appropriate texturizer and adding ratio. The results are as following: Iron ore waste rock, fly-ash and compounded texturizer can improve the high temperature viscosity of the slag respectively, while it has different effect on landing gradient of viscosity and temperature (Fly-ash occupies first place, compounded texturizer comes second and iron ore and waste rock comes the minimum). By analyzing the crystallization behavior of the slag in the solidification process, when the proportion of iron ore waste rock is more than 9%, the fly-ash is equal or greater than 8% and the compounded texturizer is more than 9%, the solidification slag will appear amorphous. The mineral composition of the slag transforms gradually from melilite to vitreous body, which will make the air hole of the vitreous body increased and aperture decreased. When the iron ore waste rock is added, the homogeneity of the air hole will deteriorate, while adding the fly-ash and compounded texturizer will strengthen the homogeneity of the air hole and make the mineral structure intensive gradually.


2015 ◽  
Vol 87 (2) ◽  
pp. 241-249 ◽  
Author(s):  
Lu Yao ◽  
Shan Ren ◽  
Xiaoqing Wang ◽  
Qingcai Liu ◽  
Lingyan Dong ◽  
...  

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