钢铁钒钛

Study on Preparation of High Quality Titanium-rich Materials by Hydrochloric Acid Leaching of Panzhihua Titanium Slag

Wu Xuan, Zhang Jianbo, Mou Huijun, Ye Endong, Zhang Xingyong

2016, 37(4): 1-7. doi: 10.7513/j.issn.1004-7638.2016.04.001

Abstract(125) PDF(8)

Abstract:
To deal with the small particle size of Panzhihua ilmenite,the processes of smelting slag with Panzhihua titanium concentrate as raw material followed by redox calcination modification and hydrochloric acid leaching were adopted to produce high quality of titanium-rich material,which provides high quality of raw materials for production of titanium dioxide by chlorination process. The experiments were conducted to determine the appropriate leaching process with the normal Ti-slag by investigating the effects of leaching pressure,additives and leaching methods on extraction efficiency of the main impurities M₃O₅ in Ti-slag which was redox modified referring to the calcination parameters for titanium concentrates modification.The results show that it is difficult to extract M₃O₅ by atmospheric pressure leaching and the addition of soluble chloride salts,ethanol and iron powder cannot efficiently improve the leaching ability of M₃O₅ in Ti-slag.Furthermore,the second stage leaching has little influence on leaching efficiency of Ti-slag.It is favorable to improve the extraction efficiency of M₃O₅ by pressure leaching or agitation leaching but qualified titanium-rich materials cannot be prepared by the mentioned methods.It is mainly attributed to a great amount of residual insoluble M₃O₅ with dense structure in the modified Ti-slag,leading to a poor reactive activity.Due to the fact that a smaller content of M₃O₅ remains in the low-grade Ti-slag with modification treatment,the hydrochloric acid leaching process coupled with external pressure and agitation was applied to the first stage of leaching using the low-grade Ti-slag with modification treatment as raw material,with leaching at 145℃ for 7 h,2:1 of liquid-solid ratio and 20% of HCl concentration.It is evidenced that the high quality titanium-rich materials with w_{TiO₂> 93% and w_∑(CaO+MgO)< 1. 5% can be obtained satisfying the requirements for raw materials of domestic fluidizing chlorination process.}

Research on Reduction-rusting Process of Panzhihua Ilmenite

Bai Tianjiao, Ding Weizhong, Shang Xingfu, Tan Dingsheng, Guo Shuqiang

2016, 37(4): 8-13,19. doi: 10.7513/j.issn.1004-7638.2016.04.002

Abstract(102) PDF(7)

Abstract:
The separation effect of iron and titanium and the existence forms of iron byproducts in NH₄Cl rusting solution for the reductive ilmenite which was obtained by oxidation at 1 000℃ for 1 h then reduction at 1 000℃ for 1 h with H₂/CO mixed gas using Panzhihua ilmenite as raw material were studied in this paper.The results show that in an appropriate reduction-rusting system for the ilmenite with 92.40%metallization rate,the TiO₂ concentration of Ti-rich material in the corrosion products can be increased to 75.12% and the addition of hydrochloric acid in the rusting solution can sequentially increase the TiO₂ concentration of Ti-rich material to 81.76%.Pure Fe₃O₄ and γ-FeO(OH),or mixture composed of Fe₂O₃,γ-FeO(OH) and α-FeO(OH) in the iron byproducts for corrosion can be obtained.

Vanadium Extraction from Carbonaceous Stone Coal by Calcination with Biomass

Zhang Shuo, Liu Kun, Liu Guangqiang, Zhang Ruiwen, Zhao Jing

2016, 37(4): 14-19. doi: 10.7513/j.issn.1004-7638.2016.04.003

Abstract(68) PDF(1)

Abstract:
The conversion rate of pentavalent vanadium in the calcination process of stone coal with biomass and additives was investigated to determine favourable parameters using Hubei carbonaceous stone coal with low vanadium concentration as raw material.It is found that the addition of biomass enhances the decarburization and roasting processes of the stone coal and the optimal reaction efficiency can be obtained by calcination at 850℃ with ratio of stone coal to biomass 7:3. Adding 4% composite additives(w_(Na₂CO₃):w_(CaCO₃)=6:4) and roasting at 950℃ for 2 h,the conversion rate of vanadium in the clinker reaches the highest value with 60% of conversion rate for pentavalent vanadium.

Removal of Vanadium from Acidic Chromium Solution by Ferric Sulfate

Li Xin, Li Ming, Liang Bin

2016, 37(4): 20-24. doi: 10.7513/j.issn.1004-7638.2016.04.004

Abstract(97) PDF(6)

Abstract:
The vanadium in acidic chromium solution,produced by the processes of sodium roasting for vanadium slag containing high concentration of chromium,leaching the roasted vanadium slag then precipitating vanadium from the leaching solution,should be removed to obtain qualified chromium products.Using ferric sulfate as agent for vanadium removal,the effects of addition amount of ferric sulfate,reaction temperature and pH value on the efficiency of vanadium removal were investigated. The results show that with mole ratio of Fe/V=9,reaction at 80℃ and 6~7 of terminal point pH,97% of the removal efficiency for vanadium can be obtained with less than 0.08 g/L of residual vanadium in the solution and less than 3.7% of chromium loss rate,which satisfies the requirements for the subsequent production of sodium dichromate or chromium sesquioxide.

Vanadium Distribution between Slag and Iron at Blow End Point and Its Phase Analysis

Liu Zhibin, Zhang Xidong, Ma Deng, Zhao Bin, Wu Wei

2016, 37(4): 25-28. doi: 10.7513/j.issn.1004-7638.2016.04.005

Abstract(58) PDF(2)

Abstract:
The vanadium extraction in combination blowing converter was simulated by 500 kg scale intermediate frequency induction furnace with top and bottom combinational blowing function,and the vanadium distribution(Lv) between iron and slag phase at blow end point was investigated. The compositions of vanadium-iron spinel were also analyzed by X-ray diffraction(XRD).The results show that vanadium distribution Lv between slag and iron at the blow end point is 1.8~2.8,which is related to the FeO content in slag.To ensure the quality of vanadium slag and decrease the FeO content with lower iron loss,the content of vanadium at the blow end point should be controlled at an appropriate high level. The formula of vanadium-iron spinel in vanadium slag was Fe O(Fe,V)₂O₃ indicating +3 for the valence of vanadium in slag phase.A small amount of V²⁺ species was evidenced to exist in the vanadium slag at the initial stage of blowing and gradually decreased with increase in oxygen supply.

Rutile TiO₂ Production by Inductive Hydrolysis of Low Concentration Titaniferous Solution with Seed Crystals Prepared by Microwave

Zhang Yaowen, Tang Siyang, Yuan Shaojun, Yue Hairong, Liu Zhangjun, Li Chun, Liang Bin

2016, 37(4): 29-34. doi: 10.7513/j.issn.1004-7638.2016.04.006

Abstract(98) PDF(2)

Abstract:
Low concentration of titaniferous solution(160 g/L) was inductively hydrolyzed with seed crystals prepared under microwave,which has a favorable energy-saving effect on TiO₂ production by sulfuric acid process.The calcination parameters of metatitanic acid were determined by TG and SEM analysis.The results show that the metatitanic acid,obtained by inductive hydrolysis with seed crystals prepared under microwave,possesses a high crystalline transfer activity that it can completely convert to rutile crystals by calcination at 850℃ for 30 min without any crystalline transfer additive. Furthermore,the prepared seed crystals can be stored for a long time making easy industrial application. The effects of salt treatment and calcination parameters on the pigmentary properties of TiO₂ were also investigated. It is evidenced that increasing the phosphorus content is beneficial to improve whiteness of the rutile TiO₂ and it can be significantly reduced by agglomeration of the particles at too low concentration of potassium? content.Rutile TiO₂ with higher whiteness and more uniform size distribution(200~350 nm) is obtained under the optimum salt treatment parameters of calcination at 900℃ for 90 min with 0.55% K₂O and 0.1% P₂O₅ added.

Research on Sand Milling Process of Rutile Titanium White

Wang Haibo, Wang Bin, Du Jianqiao, Lu Ruifang

2016, 37(4): 35-39. doi: 10.7513/j.issn.1004-7638.2016.04.007

Abstract(62) PDF(6)

Abstract:
In order to study the influence of sand milling process on properties of rutile titanium white,an initial product of rutile titanium dioxide white from the roll-in process was sand milled on a simulated vertical sand mill in laboratory. The results show that the optimum parameters for sand milling process are 30 min of grinding time,2 000 r/min of rotation speed,300 g/L of slurry concentration,65% of filling rate and 1.8 mm of selected zirconium bead size. The stability tests indicate a favorable reproducibility with an average particle size of 236 nm for the slurry after milling. The milling effects by using 1.8 mm zirconium bead are better than that of 0.6 mm industrially adopted zirconium bead. The experimental results can provide important theoretical and technical supports for the improvement of industrial sand milling process.

Effect of Graphene Content on the Corrosion Resistance and Hydrogen Adsorption-desorption Properties of the Vanadium-based Hydrogen Storage Battery

Li Shoukui

2016, 37(4): 40-43. doi: 10.7513/j.issn.1004-7638.2016.04.008

Abstract(57) PDF(1)

Abstract:
The microstructure,phase composition,corrosion resistance,hydrogen adsorption and desorption properties of the VTiNi vanadium-based hydrogen storage battery added with various contents of graphene were tested and analyzed in this paper. The results show that the graphene could significantly improve the corrosion resistance,hydrogen adsorption and desorption properties of the vanadium-based hydrogen storage battery. With increasing the graphene content,the corrosion potential of the vanadiumbased hydrogen storage battery first positively then negatively shifted,the maximum hydrogen adsorption content first increased then decreased,and the time for hydrogen adsorption to saturation first decreased then increased with the platform pressure of hydrogen desorption first basically unchanged then increased.With 1% of the optimum graphene content for the vanadium-based hydrogen storage battery,the corrosion potential positively shifted by 414 mV,the maximum hydrogen adsorption content increased by 24%,and the time for hydrogen adsorption to saturation decreased by 44%,respectively compared to that of the battery without adding graphene.

Preparation and Properties of Nano-TiO₂ Photocatalysis Material by Sol-gel Method

Yang Zaizhi, Fu Xiaoming, Wang Hongxia, Wang Yujie

2016, 37(4): 44-47. doi: 10.7513/j.issn.1004-7638.2016.04.009

Abstract(95) PDF(1)

Abstract:
Nano-TiO₂ photocatalysis material was prepared by sol-gel method using butyl titanate as precursor and polyethylene glycol as template agent. The samples of nano-TiO₂ were characterized by XRD,SEM and UV-Vis. The catalytic activities of the TiO₂ samples prepared at different calcination temperatures were tested under ultraviolet irradiation with methyl orange as simulative pollutant.The results show that the samples prepared at 500 and 600℃ are composed of single anatase phase and a mixed phase of anatase and rutile is obtained with calcination at 700℃ for the nano-TiO₂. The crystal size of the nanoTiO₂ increases with increase in the calcination temperature,leading to decrease in the degradation rate of methyl orange.The maximum adsorption peak of the nano-TiO₂ appears at the wavelength of 432 nm with a favorable adsorption effect and a quick adsorption speed,which can reach the adsorption equilibrium in about 30 min.

Research on Microstructure and Properties of Titanium Alloy by Hydraulic and Non-hydraulic Forming

Wang Junzhou

2016, 37(4): 48-52,68. doi: 10.7513/j.issn.1004-7638.2016.04.010

Abstract(37) PDF(1)

Abstract:
Electromagnetic pulse shaping is a new type of method compared with the normal hydraulic forming,which has a good application prospect. TA15 titanium alloy tube samples were respectively formed by hydraulic and electromagnetic pulse methods,and the microstructures,mechanical properties and wear resistances of the formed samples were tested and analyzed. The results show that compared with that of hydraulic forming sample the grain size of titanium alloy formed by electromagnetic pulse shaping is smaller,with better mechanical properties and wear resistance. By comparison with normal hydraulic forming,the tensile strength and elongation after fracture at 400℃ for the alloy by electromagnetic pulse shaping respectively increase by 57.48% and 34.24%,and its impact energy at-20℃ increases by 74.22% with wear volume at 400℃ decreased by 57%.

Effect of Vanadium on Precipitation Behavior in Bainite Transformation of V-Mo-N Microalloyed Steel

Chen Yuxuan, Gao Cairu, Yang Xiongfei, Zhang Dan, Ma Erqing

2016, 37(4): 53-56. doi: 10.7513/j.issn.1004-7638.2016.04.011

Abstract(50) PDF(1)

Abstract:
The distribution,morphology and size of precipitation in V-Mo-N microalloyed steel with various V content had been studied via thermal simulation and TEM observation. Hardness test was also carried out.The result shows that the second phase seems to be V(C,N) without Mo which is almost solute in the matrix. As the vanadium addition increases,the structure morphology transfers from lath bainite into granular bainite,at the same time the amount of vanadium precipitate and hardness of the steels increase.

Effects of Vanadium Micro-alloying on the Properties of Z-Beam with High Strength and Weather-resistance

Guo Yuehua, Liu Ming, Li Hongguang, Deng Tongwu

2016, 37(4): 57-61. doi: 10.7513/j.issn.1004-7638.2016.04.012

Abstract(43) PDF(2)

Abstract:
The effects of vanadium(V) micro-alloying on the properties of Z-beam with high strength and weather-resistance were researched according to the mechanical properties tests and precipitated phase analysis for the Z-beam samples prepared under different contents of vanadium and nitrogen by mediumfrequency induction furnace. The results show that V has the effects of refinement and precipitation strengthening in the Z-beam,and addition of nitrogen can enhance the transformation of V from solid solution to precipitation phase increasing the precipitation strengthening of V.It is also evidenced that the finish-rolling temperature is sensitive to the precipitation strengthening of vanadium and nitrogen. A higher precipitated V(C,N) content and yield strength of the Z-beam can be obtained at a lower finish-rolling temperature with the best matching between strength and plasticity of the Z-beam at about 850℃.

Recovery of Titanium by Solvent Extraction from Waste Sulfuric Acid Discharged in Titanium Dioxide Production

Ma Xueyang, Liang Bin, Lü Li, Liu Weizao, Li Chun

2016, 37(4): 62-68. doi: 10.7513/j.issn.1004-7638.2016.04.013

Abstract(64) PDF(6)

Abstract:
The recovery of titanium by solvent extraction from spent sulfuric acid discharged in titanium dioxide production,using primary amine N1923 and 2-octanol as agents was investigated. The effects of various process factors including stirring rate,2-octanol concentration,O/A phase ratio,extraction temperature and time on the phase disengagement and separation of titanium and iron were emphatically studied,and the influence of ammonia on stripping of titanium was also researched. The results show that using 20(v/v)% N1923 as extractant,4(v/v)% 2-octanol as modifier and 76(v/v)% sulfonated kerosene as diluent,the single stage extraction rate of titanium is above 96% with about 4% iron co-extracted at O/A=1:1,stirring rate 150 r/min,extraction temperature 30℃ and contact time 3 min. The phase disengagement time can be significantly decreased from 23 min to 4 min by addition of 2-octanol. Titanium can be effectively stripped by ammonia and 96% of single stage stripping rate for titanium is obtained with only 3 min for equilibrium. The oxidation of iron can be avoided by extraction under N₂ atmosphere with less than 0.5%iron co-extracted. The processes mentioned above was applied to industrial waste sulfuric acid discharged in titanium dioxide production,confirming the feasibility of selective and efficient recovery of titanium from industrial spent sulfuric acid by N1923-2-octanol-kerosene extraction system.

Study on the Recovery of Vanadium from Waste Catalyst in Coal-fired Power Plants

Chen Yingmin, Xie Zong, Wang Chaofan

2016, 37(4): 69-75. doi: 10.7513/j.issn.1004-7638.2016.04.014

Abstract(64) PDF(6)

Abstract:
Spent SCR catalyst contains vanadium(V),tungsten(W),titanium(Ti) and other valuable metals.Direct discard will cause not only environmental pollution but also a waste of resources,so the recovery of valuable metals from the spent catalyst has a great significance. A hydrometallurgical process for recovery of V and W from the spent catalyst was raised in this paper.V and W were firstly leached from the catalyst using NaOH solution,then the leaching solution was precipitated with calcium reagent and the obtained sediment was selectively dissolved by formic acid that V was enriched in the liquor.Undergoing impurities removal for the liquor,V can be recycled as ammonium metavanadate by adding ammonium water into the liquor for precipitation. W in the formic acid-leached sediment was extracted by hydrochloric acid to form tungstic acid and finally transformed into tungsten trioxide after calcination. The optimum parameters for NaOH leaching and formic acid selective leaching were determined by the experiments.

Study on the Performance of Corundum Castables Binded by High Titanium Blast Furnace after Extracting Titanium

Wang Peng, Han Bingqiang, Ke Changming, Li Nan

2016, 37(4): 76-82. doi: 10.7513/j.issn.1004-7638.2016.04.015

Abstract(42) PDF(2)

Abstract:
The slow cooling tailings produced in the process of silicon-titanium alloy extraction from high titanium blast slags by plasma fusion technique were used as castables binders,and the effects of the slow cooling tailings addition(wb:0percent,2 percent,4 percent,6 percent and 8 percent) on the properties of corundum castables were investigated with brown fused alumina particles(5~3 mm,3~1 mm,1~0mm),fine powder of white fused alumina(≤ 0.088 mm),ultra-fine α-alumina,and micro silica as starting materaials. The results show that:①the water requirements of castables get more,the cold and hot modulus of flexural and compressive strength of castables treated at 110℃ and 1 600℃ respectively gradually increase,however,those of castables treated at 1 100℃ decrease when addition of slow cooling tailings increasing; ②excess addition of slow cooling tailings are harmful for the thermal shock resistances and high temperature flexural strengths; ③ regarding the slag corrosion resistance,the erosion index of sample with 6% slow cooling tailings is highest,and the erosion index of sample with 4% slow cooling tailings is close to the Secar71 cement castables sample; ④the suitable addition of the slow cooling tailings for the corundum castables is about 4 percent,and not more than 6 percent.

Preparation of Composite TiO₂ Loaded on Blast Furnace Slag Fibre by Impregnation and Depositing Method

Xing Hongwei, Gu Shaopeng, Liu Xiaofan, Fu Junkai

2016, 37(4): 83-88. doi: 10.7513/j.issn.1004-7638.2016.04.016

Abstract(38) PDF(1)

Abstract:
Composite material(TiO₂/BFSF) of TiO₂ loaded on blast furnace slag fibre(BFSF) was prepared by impregnation-depositing process using BFSF as the carrier. The crystal form,grain size,specific surface area of TiO₂ and microstructure of the composite TiO₂/BFSF were characterized by XRD,particle size analyzer and Zeta potential meter,N₂ adsorption and desorption instrument,SEM and EDS,respectively.The photocatalysis performances of TiO₂/BFSF were evaluated by degradation of methylene blue(MB) simulating dyeing waste water. The results show that with 3 times of impregnation-depositing in 20 g/L TiO₂ suspension system,TiO₂ can be uniformly coated on the BFSF and 94.8% MB can be degraded by composite TiO₂/BFSF under the ultraviolet light irradiation for 180 min.After 4 times of recycle the degradation rate of MB is still maintained at 65%.

Determination of Impurities in Vanadyl Sulfate Used for Vanadium Battery by ICP-OES

Cheng Yong

2016, 37(4): 89-94. doi: 10.7513/j.issn.1004-7638.2016.04.017

Abstract(60) PDF(4)

Abstract:
The method for simultaneously determining the contents of 8 key impurities in the vanadyl sulfate solid used for vanadium battery by inductively coupled plasma atomic emission spectrometry(ICP-OES) was established respectively with the detection range of 0.001%~0.100% for Fe,Cr,Ni and 0.005%~0.100% for K,Na,Ca,Si,Al.The influences of the matrix effects,spectral interferences and continuous background superposition on the measurement of impurities in the samples with coexisting high concentration of vanadium ion and sulfate radical have been studied.It is shown that the sulfate radical in the samples does not affect the measurement,and the matrix effects or continuous background superposition generated by high concentration of vanadium ion,have a negative interference on the content determination for K and Na while a positive interference on the measurement of other impurities such as arsenic(As),cobalt(Co),iron(Fe) and nickel(Ni),etc.Meanwhile,the interference caused by high vanadium matrix was eliminated by combinative method of matrix matching and synchronous background correction.The interferences of vanadium matrix on the impurities spectra were also classified and summarized by spectral interference tests,and the analytical spectral lines,background correction regions and working parameters of the spectrometer were optimized.The technical performance indexes of this analysis method are-0.000 3%~0.000 3% of background equivalent concentration,0.000 1%~0.000 3% of element detection limit,RSD <10% with 0.001%~0.007% of element content,and 91.0%~110.0% of recovery rate.

2016, 37(4): 167-168.

Abstract(42) PDF(1)

Abstract:

Effect of Flux Type on the Properties of Magnesia Fluxed Pellet

Tian Tielei, Xu Chenguang, Zhang Yanhui, Xing Hongwei, Li Jie

2016, 37(4): 95-98. doi: 10.7513/j.issn.1004-7638.2016.04.018

Abstract(82) PDF(3)

Abstract:
In order to find the appropriate flux,the different types of flux matching is studied with respect to their influence on green pellet strength,burst temperature and compressive strength. And the suitable roasting interval of the magnesian flux pellet was investigated and the appropriate amount of liquid phase was determined by factsage software.Mineral phase composition of magnesian flux pellets was analysed by XRD to find out the evolution law of compressive strength.The results show the strength of green ball with addition of all four different flux type matching can satisfy the production demand,when flux is consisting of high magnesium powder and high calcium powder,burst temperature is optimum at 560℃. Suitable roasting temperature of high magnesia fluxed pellet is 1 240℃,suitable roasting interval was narrow at about 20℃,and suitable amount of liquid phase for the pellet is about 5%.

Effect of MgO Content on the Strength of High Magnesium Alkaline Pellets

Long Yue, Xu Chenguang, Zhang Yanhui, Tian Tielei, Zhao Bo, Xing Hongwei

2016, 37(4): 99-104. doi: 10.7513/j.issn.1004-7638.2016.04.019

Abstract(62) PDF(3)

Abstract:
In order to study the effect of MgO content on high magnesium alkaline pellet strength,Factsage thermodynamic software,liquid nitrogen adsorption instrument,and X-ray diffraction method had been used with fixed basicity of 1. 0.The results show that under the premise of 1. 0 fixed basicity,with the increase of MgO content,the amount of liquid phase in high magnesium pellet decreases,and Miaogou Iron Concentrate Ore,high magnesium powder and high calcium powder pore size distribution all are in range of 1~50 nm,which belongs to the mesoporous and relatively high magnesium powder and high calcium powder,and Miaogou iron concentrate ore area is smaller.The mechanical strength of pellet firstly increases and then decreases; roasting ball strength increases firstly and then decreases.At the given basicity of 1. 0,when the MgO content of 1.0% the strength reaches the maximum value.

Experimental Study on Carburization of Vanadium-containing Hot Metal

Ma Deng, Wu Wei, Liu Zhibin, Wang Jie

2016, 37(4): 105-111. doi: 10.7513/j.issn.1004-7638.2016.04.020

Abstract(36) PDF(2)

Abstract:
Five kind of recarburizers,namely,graphite,coke,carbon granule,low nitrogen recarburizer and anthracite are used for carbonization of vanadium-containing hot metal at temperature of 1 500℃.It is found out that graphite and low nitrogen recarburizer are the best,followed by carbon granule and anthracite,but the carburization effect of coke was the weakest.At the same time,low nitrogen recarburizer,anthracite and coke are used for carbonization experiment at temperature of 1 550℃ and 1 450℃ respectively,which demonstrate that higher temperature improves carbonization of the Vanadium-containing hot metal by increasing carburizing rate.It can be concluded that the most economical effective recarburizer is anthracite and that higher temperature favors for carbonization among temperature from 1 450℃ to 1 550℃.

Thermodynamic Analysis of Reaction Behavior of Chlorine in Blast Furnace

Lan Chenchen, Zhang Shuhui, Lü Qing, Li Fumin, Zhang Lihong

2016, 37(4): 112-118. doi: 10.7513/j.issn.1004-7638.2016.04.021

Abstract(79) PDF(2)

Abstract:
The potential chemical reactions of chlorine element in blast furnace were investigated by using the thermodynamic software(HSC Chemistry 6.0). The major chemical reactions at different range of temperature were analyzed,and the reaction behaviors were obtained under the three kinds of smelting conditions,ie,without the presence of alkali,with small amount and large amount of alkali,respectively.The results show that without presence of alkali the chlorine brought in by raw materials and fuels mostly generates HCl gas. When the alkali amount is small,chlorine is present in the form of HCl gas and alkali-chlorine. while chlorine mainly exists in the form of alkali-chloride if a large amount of alkali is present in blast furnace.. The obtained chlorine products rise along with the blast furnace gas. Some of chlorine product is absorbed in iron burden and coke and then fall down,some is discharged with blast furnace gas. In addition,small amount of chlorine element is absorbed by blast furnace slag. It is imperative that the chlorine products of blast furnace affect the smelting process of blast furnace.

First Deslagging Practice of Double Slag Process for Dephosphorization

Zhou Chaogang, Li Jing, Luo Kaimin, Han Xiao, Zhang Zhiming, Liu Zhiming, Deng Zhangfu

2016, 37(4): 119-126. doi: 10.7513/j.issn.1004-7638.2016.04.022

Abstract(69) PDF(1)

Abstract:
The effect of oxygen-supplying system,controlling of lance height,condition of the first deslagging on dephosphorization in 120 t top and bottom combined blown converter was studied based on plant trials using double slag process.The results show that the optimum conditions for dephosphorization are as follows:the time of blowing oxygen and blowing oxygen quantity should be controlled at between 390~420 s and 2 300~2 400 m³ respectively during the first deslagging; Phosphorus content of liquid steel at the first deslagging can be reduced to minimum 0. 032%,and maximum dephosphorization rate reached 75.57% in the industrial experiment when temperature,basicity,FeO,and P₂O₅ were 1 400~1 420℃, ≥ 2.06, ≥ 10.97% and 2.54%~3.0% respectively at the first deslagging.

Thermodynamic Activity of Components in CaO-MgO-Al₂O₃-SiO₂ Refining Slag System

Tang Guozhang, Li Junguo, Ceng Yanan, Zhao Lina

2016, 37(4): 127-132. doi: 10.7513/j.issn.1004-7638.2016.04.023

Abstract(198) PDF(6)

Abstract:
In order to explore the relationship between refining slag,molten steel and inclusion,the activity of components in CaO-MgO-Al₂O₃-SiO₂ refining slag is calculated by Factsage software.The results indicate that a_Al₂O₃,a_CaO,a_MgO,a_SiO₂ at 1 600℃ ranges from 0.003 to 0.04,from 0.35 to 0.9,from 0.49 to 0. 9,from 0.000 08 to 0.000 5,respectively,when w_MgOis 5%.With the MgO content increasing to 7%,liquid phase zones of refining slag has reduced.In addition,the activity of refining slag has small fluctuation.Furthermore,with the MgO content increasing to 10%,a_Al₂O₃ can be increased by improving the Al₂O₃ content and decreasing the basicity(R) at the high basicity.On the contrary,a_CaO、a_MgO and a_SiO₂ can be increased by improving the basicity and decreasing the content of Al₂O₃.In addition,the activity of refining slag obtained from hot experiments and thermodynamic simulation are consistent,which indicates that the thermodynamic simulation by Factsage is feasible in predicting the activity of refining slag.

Effect of Calcium Treatment on Low Temperature Toughness of Corrosion Resistant Steel

Wu Zhanfang, Xu Lijun, Dong Fujun, Chou Shengtao, Li Xiangyang

2016, 37(4): 133-138. doi: 10.7513/j.issn.1004-7638.2016.04.024

Abstract(43) PDF(1)

Abstract:
In order to stabilize the low temperature toughness of corrosion resistant steel,effect of calcium treatment on low temperature toughness of corrosion resistant steel has been studied.The results show that compared with the traditional calcium treatment process,the modified calcium treatment process can greatly improve the low temperature impact properties of steel tested at the temperature of -20℃ and -40℃.When the inclusions are spherical calcium aluminate +CaS composite inclusions and dispersed,the test steel at -20℃ impact energy(transverse) was improved by 24.6%,and the value at -40℃ impact energy(transverse) was improved by 44.5%,and the impact values the sample along longitudinal direction was improved by 33.7% and 32.7% respectively.The modified calcium treatment technology can improve the absorption rate of[Ca] in the molten steel which makes it more effective and a steel plate of with satisfied low temperature impact toughness was obtained.

Effect of Microstructure on Stretch-flangeability of Ferrite-bainite Dual Phase Steel

Xiao Heng, Li Hui, Zhou Herong, Wu Run

2016, 37(4): 139-142. doi: 10.7513/j.issn.1004-7638.2016.04.025

Abstract(44) PDF(2)

Abstract:
The relationship between microstructure and the stretch-flangeability of F+B dual phase steels had been studied by observing the microstructure of F+B dual phase steels with different hole expansion ratio.When the microstructure consists of polygonal ferrite and granularbainite,the DP steel exhibited excellent stretch-flangeability. Polygonal ferrite is beneficial to the hole expansion ratio,while lower bainite and lath bainite play negative roles. The M-A islands in bainite have a great effect on the stretch-flangeability. As the size of M-A islands decrease,the hole expansion ratio improves. When the width of M-A islands is 0.7 μm,the hole expansion ratio of F+B steel reaches up to 120%.

Improving the Sheared-edge Formability of High Strength Dual-phase Steel

Gong Yu, M.Hua, J.Uusitalo, A.J.Deardo

2016, 37(4): 143-151. doi: 10.7513/j.issn.1004-7638.2016.04.026

Abstract(36) PDF(1)

Abstract:
Dual phase steels are commercially attractive since they offer good formability at a high strength.These steels exhibit high n-values and high uniform and total tensile elongations. However,one limitation in the application of high strength dual phase steels is failure during sheared edge stretching.In order to develop high strength dual phase steels with improved sheared edge ductility,the amount and hardness of both the hard and soft constituents must be carefully controlled. The failure mechanism observed during stretching of the sheared edge is closely related to the microstructures(i.e.amounts,hardness,size and distribution of different phases),and the initiation of cracks were found to start at ferritemartensite interfaces which will be discussed in this study.In the present research,the effects of pre-annealing conditions(hot and cold rolling),different CGL processing paths and alloying elements on the sheared edge formability of dual phase steels have been studied. It has been found that all three of these variables can exert a strong influence of sheared edge ductility as determined in the hole expansion test.

Trial Production of High-strength Microalloying 20MnSi Reinforced Bar

Liu Xiangjun, Yang Jichun, Zhang Jian, Zhang Wenhuai, He Yaoyu, Li Kun

2016, 37(4): 152-156. doi: 10.7513/j.issn.1004-7638.2016.04.027

Abstract(63) PDF(1)

Abstract:
The method of trial production of high-strength microalloying 20 MnSi reinforced bar had been present in this paper. The mechanical properties and microstructures of the tested steel were investigated by universal tensile machine,scanning electron microscopy and transmission electron microscope. It was found out that the yield strength,tensile strength,elongation and yield ratio were 831 MPa,1 140 MPa,29.1% and 0.79,respectively,for the steel with 0.04%N and 0.047%V. It is expected that the improvement in mechanical properties of tested steel is attributed to the vanadium and titanium carbonitride precipitation strengthening.

Production of Subway Wheel Steel ER7 with Micro-alloying of Vanadium and Chromium

Li Shu

2016, 37(4): 157-161. doi: 10.7513/j.issn.1004-7638.2016.04.028

Abstract(66) PDF(2)

Abstract:
The producing process and properties of subway wheel steel ER7 is researched with the routine of LD-LF-VD-CC,by micro-alloying of vanadium and chromium,calcium treatment and sulfur wire-feeding.Carbon segregation,center porosity and shrinkage cavity was effectively improved by steel superheat,second cooling and F-EMS parameter control. The properties of steel,such as the strength,ductility,plasticity and anti-fatigue is qualified.

Analysis on Corner Fine Cracks and Scaling Defects of U75V Rail

Kou Shasha, Liang Zhengwei, Liu Li, Li Zhili, Zhang Na

2016, 37(4): 162-166. doi: 10.7513/j.issn.1004-7638.2016.04.029

Abstract(83) PDF(7)

Abstract:
Corner fine cracks and scaling defects could be found on the U75V rail after being used in the curve segment for a period of time.The reason for defects was analyzed by means of chemical analysis,mechanical testing,metallurgical testing and scanning electron microscope.The results showed that the damage was nothing to do with the quality of rail,corner fine cracks and scaling defects were caused by rolling contact fatigue under high contact stress.Such damage could be prevented by optimizing wheel/rail profile,setting up appropriate deficient super elevation,grinding and oiled in time,and selecting reasonable rails.

2016 Vol. 37, No. 4