Effect of B2O3 on the carbothermal reduction of vanadium titanium magnetite

2019 ◽  
Vol 116 (6) ◽  
pp. 630 ◽  
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.

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

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 219 ◽  
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.

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

2012 ◽  
Vol 217-219 ◽  
pp. 441-444 ◽  
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.

Experimental process and kinetic behavior of carbothermal reduction of lithium cobaltate as a cathode for waste lithium batteries

2021 ◽  
Vol 11 (12) ◽  
pp. 1988-1996
Author(s):  
Cao Zhi-Kang ◽  
Li Ji-Dong ◽  
Li Zhen ◽  
Wang Xue-Lian ◽  
Yue Ling-Feng
Keyword(s):  
Cathode Material ◽  
Lithium Ion Batteries ◽  
Calcination Temperature ◽  
Carbothermal Reduction ◽  
High Efficiency ◽  
Diffusion Mechanism ◽  
Reduction Rate ◽  
Reduction Process ◽  
Lithium Ion ◽  
Lithium Cobaltate

Lithium cobaltate as a cathode material has great recycling value in the recycling process of spent lithium-ion batteries, To promote the thermal reduction process of lithium cobaltate and recover high-value cobalt and lithium metals, we studied the process of lithium cobaltate reduction by carbon under different conditions and its thermal reaction kinetics. The effects of calcination temperature, raw material ratio, pelletizing pressure and holding time on the reduction rate of lithium cobaltate were investigated by controlling variables. The results showed that the optimum experimental conditions were as follows: mass ratio of carbon and lithium cobaltate was 1:1, pelletizing pressure was 45 MPa, calcination temperature was 800 °C, and calcination time was 6 h. Under these conditions, lithium cobaltate could be converted into cobalt and lithium carbonate, and the recovery rate of cobalt and lithium was 97% and 95%, respectively. A kinetic study on the carbothermal reduction reaction of LiCoO2 showed that the average activation energy of the carbothermal reaction of LiCoO2 under nitrogen protection was 280.6851 kJ/mol, and the mechanism model of the thermal decomposition reaction of LiCoO2 was controlled by chemicals, showing a deceleration curve. The corresponding process conforms to the threedimensional diffusion mechanism of the inverse Jander equation, which lays a theoretical foundation for the high-efficiency separation and recovery of LiCoO2 cathode material for waste lithium-ion batteries.

Porous AlN Ceramics Fabricated by Carbothermal Reduction

2014 ◽  
Vol 788 ◽  
pp. 627-631
Author(s):  
Yuan Lu ◽  
Jing Long Li ◽  
Jian Feng Yang ◽  
Peng Li
Keyword(s):  
Mechanical Properties ◽  
Carbothermal Reduction ◽  
Glass Phase ◽  
Sintering Temperature ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
High Porosity ◽  
Sintering Additives ◽  
Fine Microstructure ◽  
Complete Formation

A new method for preparing porous AlN ceramics with high porosity had been developed by carbothermal reduction of die-pressed green bodies composed of alumina, carbon, sintering additives and AlN seeds. The influences of sintering additives and sintering temperature on the microstructure and mechanical properties of porous AlN ceramics were investigated. XRD analysis proved that complete formation of AlN phase except for minor of glass phase. SEM analysis showed that the resultant porous AlN ceramics occupied fine microstructure and a uniform pore structure. Porous AlN ceramics with a porosity of 41~66% and a strength of 2.7~ 51.8 MPa were obtained.

Effects of Sintering Additives on Properties of Porous Silicon Nitride Ceramics Fabricated by Carbothermal Reduction

2008 ◽  
Vol 368-372 ◽  
pp. 878-880 ◽  
Author(s):  
Yuan Lu ◽  
Jian Feng Yang ◽  
Shao Yun Shan ◽  
Ji Qiang Gao ◽  
Zhi Hao Jin
Keyword(s):  
Carbothermal Reduction ◽  
Sintered Sample ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
Sintering Additives ◽  
Sintering Additive ◽  
Fine Microstructure ◽  
Porous Si3n4 ◽  
Si3n4 Ceramics ◽  
Porous Si3n4 Ceramics

In this paper, porous Si3N4 ceramics were fabricated by carbothermal reduction between silicon dioxide and carbon. The influences of four types of sintering additives on the microstructure and mechanical properties of the porous Si3N4 ceramics were investigated. XRD analysis proved complete formation of a single-phase β-Si3N4. SEM analysis showed that the resultant porous Si3N4 ceramics occupied fine microstructure and a uniform pore structure. The sintered sample with Lu2O3 as sintering additive showed finer, a higher aspect ratio β-Si3N4 grains. The addition of Eu2O3 accelerated the densification of porous Si3N4 ceramics, decreased the porosity and increased the flexural strength.

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

2021 ◽  
Vol 267 ◽  
pp. 02046
Author(s):  
Bo Wang ◽  
Xueyong Ding ◽  
Xiaofei Zhang ◽  
Tianhua Ju ◽  
Shigang Li
Keyword(s):  
Rotary Kiln ◽  
Flue Gas ◽  
Reduction Process ◽  
Reduction Mechanism ◽  
Gas Analyzer ◽  
Metallization Rate ◽  
Vanadium Titanium ◽  
Reduction Effect ◽  
Calcium Catalysts ◽  
Titanium Magnetite

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.

Study on Smelting Metallic Magnesium by Siliconthermic Reducing Method and its Reaction Kinetics

2010 ◽  
Vol 129-131 ◽  
pp. 1133-1137
Author(s):  
Feng Gao ◽  
Wang Guo Sheng ◽  
Liu Yun Yi ◽  
Ying Xin Ge ◽  
Wang Zhu Min
Keyword(s):  
Activation Energy ◽  
Raw Materials ◽  
Three Dimensional ◽  
Reduction Rate ◽  
Reduction Process ◽  
Frequency Factor ◽  
Reduction Temperature ◽  
Metallic Magnesium ◽  
Boundary Reaction ◽  
Phase Boundary Reaction

The metallic magnesium by siliconthermic reducing method was studied by magnetite as raw materials. The Mg reduction rate, such as reduction temperature and time, Si-Fe added mount, mineralize CaF2 added, briquette pressure, were discussed by experiments. Through siliconthermic reducing process analyzed, the result showed reduction process was in line with three-dimensional phase boundary reaction D3 model and kinetic equitation were expressed as , with an apparent activation energy 313.58 KJ/mol, frequency factor 2.7×106 s-1.

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

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.

Porous Silicon Nitride Ceramics Prepared by Reduction – Nitridation of Diatomite

2009 ◽  
Vol 620-622 ◽  
pp. 753-756
Author(s):  
Yao Hui Xue ◽  
Yuan Lu ◽  
Bo Wang ◽  
Jian Feng Yang ◽  
Wei Zhong Lu ◽  
...  
Keyword(s):  
Carbothermal Reduction ◽  
Sedimentary Rock ◽  
Aquatic Plant ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
Main Ingredient ◽  
Nitride Ceramics ◽  
Fine Microstructure ◽  
Si3n4 Ceramics ◽  
Porous Si3n4 Ceramics

In this paper, porous Si3N4 ceramics were fabricated by carbothermal reduction between carbon black and diatomite. Diatomite is a siliceous, sedimentary rock consisting principally of the fossilized skeletal remains of diatom, a unicellular aquatic plant related to the algae. The main ingredient of diatomite is the amorphous active silicon dioxide. The influence of diatomite particle size on the microstructure of sintering bodies was analyzed. XRD analysis demonstrated the formation of Si3N4 except for minor of glass phase. SEM analysis showed that the resultant porous β-Si3N4 ceramics occupied fine microstructure and uniform pore structure.

Kinetics of Magnesium Removal from Garnierite by Carbothermal Reduction in Vacuum

2020 ◽  
Vol 996 ◽  
pp. 165-172
Author(s):  
Xu Peng Gu ◽  
Xiao Pan Zhang ◽  
Tao Qu ◽  
Ming Yang Luo ◽  
Lei Shi ◽  
...  
Keyword(s):  
Chemical Reaction ◽  
Carbothermal Reduction ◽  
Removal Rate ◽  
Reduction Process ◽  
Magnesium Silicate ◽  
Reduction Reaction ◽  
Sem Analysis ◽  
Exponential Factor ◽  
Chemical Reaction Kinetics ◽  
Kinetics Of

The removal of magnesium from garnierite in Yuanjiang area of Yunnan was performed by carbothermal reduction in vacuum. The effects of reduction temperature and reduction time on the removal rate of magnesium were investigated. The kinetics of the removal of magnesium by carbothermal reduction in vacuum was studied. The thermodynamic calculation results show that it is feasible to remove magnesium from garnierite by carbothermal reduction in vacuum. The experimental results show that the removal rate of magnesium in garnierite can reach 93.23% under the conditions of 1823K for 120min. The reduction process conforms to the chemical reaction kinetics model, which indicated that the reduction process is controlled by chemical reaction and whose expression is 1-(1-α)1/3=(-22850.1/T+2.6296) t, the apparent activation energy (Ea) and the pre-exponential factor (A) are 189.97 kJ/mol and 13.87 s-1, respectively. The results of XRD and SEM analysis show that the condensate obtained by carbothermal reduction in vacuum of the garnierite is magnesium, which is mainly obtained by the reduction reaction between magnesium silicate produced by the decomposition of serpentine in minerals and coal. At the same time, it is proved that it is feasible to directly extract magnesium metal from the garnierite.

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