Effect of catalyst on tail gas during reduction of vanadium-titanium magnetite carbon-containing pellet

Catalyst can enhance the reduction effect and promote the reduction of vanadium titanomagnetite. In this paper, the carbon-containing pellets of vanadium titanomagnetite were prepared by using highly volatile coal as the reducing agent under the background of a novel process of pre-reduction in the rotary kiln. The effects of CaO, CaCO3, B2O3 and borax (Na2B4O7·10H2O) on the tail gas characteristics of carbon-containing pellets in the prereduction process were studied by using a simulated rotary kiln and flue gas analyzer. The results showed that the enhanced reduction effect of boron catalysts was slightly stronger than that of calcium catalysts, among which CaO catalyzed the least and borax the best. With the increase of metallization rate, the CO utilization in the tail gas is generally reduced, while when using CaCO3 as the catalyst, the CO utilization is significantly increased. Due to different reduction mechanism, the boron catalysts have little effect on the tail gas, and the calcium catalysts have a great effect on the tail gas. Based on the experimental results and the characteristics of the tail gas from the reduction process, we put forward the idea of using CaCO3 as the best catalyst and using CaO to absorb CO2 in the tail gas to form CaCO3.

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The effect of composite reducing agent on the reduction process and the tail gas of carbon-containing pellets

E3S Web of Conferences ◽

10.1051/e3sconf/202126702040 ◽

2021 ◽

Vol 267 ◽

pp. 02040

Author(s):

Bo Wang ◽

Xueyong Ding ◽

Xiaofei Zhang ◽

Tianhua Ju ◽

Shigang Li

Keyword(s):

Rotary Kiln ◽

Bituminous Coal ◽

Reduction Process ◽

Reducing Agent ◽

Process Conditions ◽

Metallization Rate ◽

New Type ◽

Vanadium Titanium ◽

Ironmaking Process ◽

Titanium Magnetite

In order to explore a reasonable way for the efficient utilization of coal resources in the ironmaking process. In this paper, lignite and bituminous coal are used as reducing agents, and two types of vanadium-titanium magnetite composite reducing agent pellets are prepared for different content ratios and mixed forms of the two coal powders. Under the simulated rotary kiln pre-reduction conditions, the influence of the ratio and mixing of pulverized coal on the metallization rate and tail gas composition of the reduction process was explored. The results show that increasing the proportion of high volatile lignite is beneficial to the reduction of pellets and can obtain pellets with a higher metallization rate. Under the new pre-reduction process conditions of the rotary kiln, the vanadium-titanium magnetite double-layer pellet with 75wt% lignite inside and 25wt% bituminous coal outside has the highest metallization rate of about 76%. At the same time, this new type of composite reducing agent pellets reduced gas emissions. This pellet is of great significance to the coal-based ironmaking process.

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Influence of Parameters on the Pre-Reduction Process of Vanadium-Titanium Magnetite Carbon-Containing Composite Pellets in Rotary Kiln

Metals ◽

10.3390/met11010045 ◽

2020 ◽

Vol 11 (1) ◽

pp. 45

Author(s):

Bo Wang ◽

Xueyong Ding ◽

Tianhua Ju ◽

Xiaofei Zhang ◽

Gongjin Cheng

Keyword(s):

Rotary Kiln ◽

Reduction Process ◽

Holding Time ◽

Reduction Temperature ◽

Smelting Reduction ◽

Total Oxygen ◽

Metallization Rate ◽

Composite Pellets ◽

Melting Pool ◽

Titanium Magnetite

A novel smelting reduction process called pre-reduction in rotary kiln and total oxygen melting pool is a promising route to reduce environmental pollution from the ironmaking industry. In this paper, the process parameters and appropriate efficiency of reduction in the pre-reduction process of the rotary kiln were investigated via the detection of the metallization rate, phase composition, and internal morphology of the product combining with the analysis of the off-gas. The results indicated that the parameters of reduction temperature, reduction holding time, and coal ratio have a remarkable influence on the metallization rate. The reduction temperature has the most significant effect, followed by the reduction time and the coal ratio. Furthermore, under the condition of reduction temperature 1000 °C, holding time 30 min, coal ratio = 1, a product with a metallization rate of more than 70% can be obtained, which meets the requirements of the rotary kiln process, and its CO2/CO value of the pre-reduction endpoint is appropriate. Continue to increase the temperature, holding time, and coal ratio can raise the metallization rate of the pellets, but only a little improvement and may cause reoxidation of the product.

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Study on Utilization Technology of Vanadium Titanium Magnetite Based on the Rotary Hearth Furnace Direct Reduction Process

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.217-219.441 ◽

2012 ◽

Vol 217-219 ◽

pp. 441-444 ◽

Cited By ~ 1

Author(s):

Gong Guo Liu

Keyword(s):

Recovery Rate ◽

Large Scale ◽

Direct Reduction ◽

Reduction Rate ◽

Reduction Process ◽

Direct Reduction Process ◽

Metallization Rate ◽

Study Results ◽

Vanadium Titanium ◽

Titanium Magnetite

Through carrying out large scale of experiments, the process of ‘rotary harth furnace direct reduction—deep reduction electric arc furnace—extracting vanadium from vanadium bearing slag—extracting titanium from titanium bearing slag gets through and the recovery of Fe, V and Ti reached 90.77%, 43.82% and 72.65% respectively. With the study on the laboratory experiments and industrial tests, the bottlenecks of this technology such as low metallization rate of vanadium-titanium magnetite in direct reduction process, low reduction rate of vanadium in EAF, vanadium-recovery of hot metal with high silicon content, titanium-recovery of high –Mg &Al slag with titanium, and so on, have been solved. Based on this, the metallization rate of vanadium-titanium magnetite in direct reduction process is more than 90%, reduction rate of vanadium in EAF deep reduction process is more than 80%, vanadium-recovery rate in slag is more than 65%, and titanium-recovery rate in slag is more than 75%. That means good study results have been gotten. Furthermore, low-carbon pig iron with good quality in EAF steelmaking are gotten. Otherwise, V2O5 sheet and titanium products can meet the requirements of GB3283-87 and PTA121, respectively.

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Experimental Study on Strengthening Carbothermic Reduction of Vanadium-Titanium-Magnetite by Adding CaF2

Minerals ◽

10.3390/min10030219 ◽

2020 ◽

Vol 10 (3) ◽

pp. 219 ◽

Cited By ~ 1

Author(s):

Xiangdong Xing ◽

Yueli Du ◽

Jianlu Zheng ◽

Yunfei Chen ◽

Shan Ren ◽

...

Keyword(s):

Carbothermic Reduction ◽

Reduction Rate ◽

Reduction Process ◽

Complex Compounds ◽

Carbon Gasification ◽

Promotive Effect ◽

Mass Fractions ◽

Vanadium Titanium ◽

Gasification Reaction ◽

Titanium Magnetite

The effects and reduction mechanisms of carbothermic reduction of vanadium–titanium–magnetite were studied by adding various mass fractions of CaF2 ranging from 0%, 1%, 3%, 5% to 7%. The results showed that the proper CaF2 addition could strengthen the carbothermic reduction of vanadium–titanium–magnetite while the excessive amounts will weaken the promotive effect, hence the appropriate dosage was determined to be 3 mass%. The CaF2 was favorable for the carbon gasification reaction, where it increased the partial pressure of CO inside briquette and caused the lattice distortion of vanadium–titanium–magnetite. The reaction improved the reduction process and accelerated the reduction rate. The appearance of 3CaO·2SiO2·CaF2 and other complex compounds with low melting point facilitated the aggregation and growth of the slag and the iron, which increased the concentration of iron grains and the aggregation level of the slag.

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Carbothermic reduction mechanism of vanadium-titanium magnetite

Journal of Iron and Steel Research International ◽

10.1016/s1006-706x(16)30065-6 ◽

2016 ◽

Vol 23 (5) ◽

pp. 409-414 ◽

Cited By ~ 5

Author(s):

Shuang-yin Chen ◽

Xiao-jiao Fu ◽

Man-sheng Chu ◽

Xi-zhe Li ◽

Zheng-gen Liu ◽

...

Keyword(s):

Carbothermic Reduction ◽

Reduction Mechanism ◽

Vanadium Titanium ◽

Titanium Magnetite

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Study of the reduction mechanism of ironsands with addition of blast furnace bag dust

Metallurgical Research & Technology ◽

10.1051/metal/2017097 ◽

2018 ◽

Vol 115 (2) ◽

pp. 214 ◽

Cited By ~ 3

Author(s):

Xiangdong Xing ◽

Yunfei Chen ◽

Yiran Liu

Keyword(s):

Compressive Strength ◽

Blast Furnace ◽

Reduction Process ◽

Xrd Analysis ◽

Reduction Mechanism ◽

X Ray Diffraction ◽

Carbon Gasification ◽

Metallization Rate ◽

Addition Rate ◽

Gasification Reaction

To improve the reduction properties of ironsands carbon-containing briquettes, the behavior of ironsand during reduction by the addition of blast furnace bag dust (BFBD) is studied using a high temperature resistance furnace, X-ray diffraction (XRD) analysis and scanning electron microscopy. Additionally, the reduction mechanism is discussed in this study. The results showed that the reduction level and compressive strength of ironsand carbon-containing briquettes could be promoted by increasing the proportion of BFBD. When the addition rate of BFBD was 31.25%, the metallization rate and compressive strength increased from 82.1% and 21.5 N/a to 91.4% and 172.5 N/a, respectively. Metallic iron reduced from BFBD particles favored the carbon gasification reaction, which enhanced the internal CO concentration, and then promoted the FeTiO3 reduction to Fe in ironsand. Meanwhile, a large amount of the liquid phase generated during the reduction process also favored Fe2+ diffusion, spread of iron joined crystals and the growth of crystals, which resulted in the improvement of the compressive strength of the ironsand carbon-containing briquettes.

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Reduction mechanism of high-chromium vanadium–titanium magnetite pellets by H2–CO–CO2 gas mixtures

International Journal of Minerals Metallurgy and Materials ◽

10.1007/s12613-015-1108-9 ◽

2015 ◽

Vol 22 (6) ◽

pp. 562-572 ◽

Cited By ~ 19

Author(s):

Jue Tang ◽

Man-sheng Chu ◽

Feng Li ◽

Ya-ting Tang ◽

Zheng-gen Liu ◽

...

Keyword(s):

Gas Mixtures ◽

Reduction Mechanism ◽

Co2 Gas ◽

High Chromium ◽

Magnetite Pellets ◽

Vanadium Titanium ◽

Titanium Magnetite

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Effect of B2O3 on the carbothermal reduction of vanadium titanium magnetite

Metallurgical Research & Technology ◽

10.1051/metal/2019053 ◽

2019 ◽

Vol 116 (6) ◽

pp. 630 ◽

Cited By ~ 1

Author(s):

Xing Xiangdong ◽

Wang Sha ◽

Pang Zhuogang ◽

Zhang Qiuli

Keyword(s):

Melting Point ◽

Carbothermal Reduction ◽

Three Dimensional ◽

Reduction Rate ◽

Reduction Process ◽

Xrd Analysis ◽

Sem Analysis ◽

Vanadium Titanium ◽

First Order Chemical Reaction ◽

Titanium Magnetite

The effect of B2O3 on the carbothermal reduction of vanadium titanium magnetite was investigated under different temperatures by isothermal experiments. XRD analysis, SEM analysis and kinetic analysis were used to reveal the mechanism of B2O3 in the reduction process. The results showed that B2O3 could accelerate the reduction rate of vanadium titanium magnetite, and the suitable addition amount was 3%. B2O3 was easy to melt during carbothermal reduction, B3+ diffused into the crystal lattice of ferrotitanium compound, resulting in a decrease in binding energy and an increase in lattice parameters. B2O3 had also an erosion effect on the surface of the iron ore, and the contact area between reducing agent CO and vanadium titanium magnetite increased, thereby promoting the reduction. Low melting point compound CaO ∙ B2O3 formed after adding B2O3, which could improve the fluidity of the system and change the melting point of non-ferrous phase to further promote the growth and aggregation of iron particles. The reduction process was firstly limited by the first-order chemical reaction, then it was controlled by three-dimensional diffusion of reactants. The activation energy calculated by the best model was smaller than that of without adding B2O3.

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