浓硫酸焙烧高钛渣的反应动力学（英文）

提出一种新方法,利用浓硫酸焙烧高钛渣提取二氧化钛,并在焙烧工艺的基础上研究焙烧反应动力学。考察焙烧温度、粒度以及酸矿比对反应速率的影响。结果表明,焙烧反应符合未反应核收缩模型。动力学实验数据、SEM和EDAX结果分析表明,用浓硫酸焙烧高钛矿渣的反应受通过固体产物层的内扩散控制。Arrhenius方程得到焙烧反应的表观活化能为18.94 kJ/mol。     

低品位高钛渣中钛组分制备金红石(英文)

介绍了以70%～75%TiO2的低品位高钛渣为原料制备人造金红石的分离工艺。低品位高钛渣中MgO,FeO,CaO,Al2O3和SiO2进入杂质相,钛组分进入金红石相,金红石相中TiO2品位达到90%～95%,可满足流态化氯化对杂质的要求。1050℃的低温预氧化与1510℃的高温热处理促使渣中分散于各矿物相的钛组分选择性转移并富集于金红石相,金红石相析出与长大,用稀硫酸和稀盐酸实现金红石相的分离。实验结果表明,金红石矿物相平均晶粒度可以达到25μm,通过稀酸选择性浸出改性渣,可以获得95%TiO2品位的人造金红石。     

高钛渣粒度问题探析

根据使用球磨机、棒磨机和取沙球（棒）磨设备的破碎工艺的高钛渣粒度分布状况，得出了取消球（棒）磨设备的破碎工艺，为解决我厂高钛渣粒度过细难题的首选方案。     

攀枝花含钛高炉渣直接制备钛合金

采用固体透氧膜(SOM)法研究直接电解攀枝花含钛高炉渣制备钛硅合金.以经过1 150 ℃预烧2 h成型的攀枝花含钛高炉渣为阴极,以氧化锆管内碳饱和铜液为阳极,将两者置于CaCl2熔盐中,在1 100 ℃、电解电压3.5～4.0 V的条件下高温熔盐电解2～8 h.采用SEM、EDX和XRD等方法对电解产物进行分析.结果表明:含钛高炉渣电解还原后的产物为TixSiy系合金,含钛高炉渣中钙、镁和铝等金属元素被有效去除.     

铝热还原酸溶性钛渣制备TiAl基多元合金

对含高钛的酸溶性钛渣进行铝热还原制备钛铝基多元合金。为了控制并了解合金的制备,讨论了铝和氧化钙的添加和温度的影响。通过考虑材料的配比计算,可以成功地使合金与渣合金分离。大多数还原元素的回收率表现为高值,在所有实验条件下均为95%。铝的添加主要影响合金的成分,而氧化钙的添加则通过改变渣系成分来影响渣金分离。此外,系统的温度可以提高大部分还原元素的回收率和分配比。     

基于氢化脱氢钛粉制备低成本高性能钛合金

粉末冶金是短流程制备低成本、高性能钛及钛合金的有效方法之一。采用氢化脱氢(HDH)制粉—冷等静压成形—真空烧结致密化的技术路线制备了间隙原子含量低(O <0. 16%、N <0. 05%、H <0. 015%,质量分数)、具有均匀细小近等轴α组织且室温拉伸性能(R_m为840～950 MPa、R_(P0. 2)为770～900 MPa、A为12%～16%)良好的Ti-6Al-4V合金烧结坯,证明了HDH工艺制备低间隙原子含量钛粉的可行性,而间隙原子含量的增加主要源于粉末及压坯的操作、转移和储存过程。由于粉末冶金钛合金具有细晶和近净成形的特点,无需开坯锻造,并且近净成形的烧结坯能够提高材料利用率,减少后续热加工变形量及加工道次。因此,以粉末钛合金烧结坯替代锻坯进行后续的塑性加工能够大幅度降低钛合金构件及型材的成本。     

镁对氢化钛烧结致密化的影响

以氢化钛粉末和镁粉为原料,利用模压工艺制备纯钛,主要研究了镁对氢化钛粉末烧结致密化的影响。结果表明,少量镁的添加能够促进氢化钛粉末的烧结致密化,而过量镁则降低烧结密度,镁添加量为0.5%(质量分数,下同)时效果最优,将烧结体相对密度由96.5%提高到98.7%。通过对烧结过程动力学、镁还原氧化钛反应的热力学和动力学,以及烧结体成分进行分析,发现少量镁促进氢化钛烧结致密化的机理为:真空烧结时镁从坯体中挥发,形成的镁蒸气对粉末颗粒表面的氧起到净化作用,提高了烧结活性,从而提高烧结密度。     

攀枝花新建高钛渣厂需要解决的几个主要问题

我国的钛矿资源主要集中在攀西地区,攀西地区的钛资源已探明的储量占全世界的35.17％,占国内的91％。目前我国钛铁精矿产量的1/3出自攀枝花。我国钛工业要有质的飞跃,大力开发攀西钛资源、启动攀枝花钛工业已势在必行,这也是国内多数钛专家的共识。     

Decomposition of acid dissolved titanium slag from Australia by sodium hydroxide

The kinetics of the decomposition of acid dissolved titanium slag with a sodium hydroxide system under atmospheric pressure was studied. The effect of reaction temperature, particle size and NaOH-to-slag mass ratio on titanium extraction was investigated. The results show that temperature and particle size have significant influence on titanium extraction. The experimental data of titanium extraction show that the shrinking core model with chemical reaction controlled process is most applicable for the decomposition of slag, with an apparent activation energy of 62.4 kJ·mol⁻¹. Approximately 85 wt.%−90 wt.% of the titanium can be extracted from the slag under the optimal conditions. In addition, the purity of titanium dioxide obtained in the product is up to 98.5 wt.%.     

Preparation of Ti-rich material from titanium slag by activation roasting followed by acid leaching

A method of activation roasting followed by acid leaching using titanium slag was introduced to prepare Ti-rich material. The effects of H₃PO₄ dosage, roasting temperature, and roasting time on TiO₂ grade were investigated. A Ti-rich material containing 88.54% TiO₂, 0.42% (CaO+MgO) was obtained when finely ground titanium slag was roasted with 7.5% H₃PO₄ at 1000 °C for 2 h, followed by a two-stage leaching in boiling dilute sulfuric acid for 2 h. The XRD patterns show that the product is titanium dioxide with a rutile structure. Mechanism studies show that structures of anosovite solid solution and silicate minerals are destroyed in the roasting process. As a result, titanium components in titanium slag are transformed into TiO₂ (rutile) while impurities are transformed into acid-soluble phosphate and quartz.     

Laser cladding of titanium alloy coating on titanium aluminide alloy substrate

1　INTRODUCTIONInthedesignandmanufactureofaviationindus try ,differentpartsoftheaircraftengineshouldmeetthedifferentrequirementsonoperatingtemperatureandserviceperformance .Thesoundbondofdissimi laralloysisthekeytechniquefordevelopingnovele quipmentsandimprovingtheirintegralperformance .Lowdensityandexcellenthigh temperaturepropertiesofTiAlalloysmakethem promisinghigh temperaturestructuralmaterials .Successfuljoiningofthesematerialswillincreasetheirutilityinengineer ing[1,2 ] .Somejoinin…     

密闭直流电弧炉冶炼钛渣热量平衡研究

密闭直流电弧炉冶炼生产钛渣利用输入电能进行加热,在高温情况下,钛精矿中的FeO和TiO2发生还原反应.反应进行程度影响熔池内渣的粘度,进而影响炉壁挂渣层的厚度和排渣排铁的难易程度,故还原反应过程必须控制输入能量使DC炉系统达到热量平衡；输入能量过高会使熔池内的渣过热,挂渣层变薄,造成炉壁腐蚀；输入能量过低,会导致渣的粘度明显增大,造成排渣困难,并产生泡沫渣.根据理论计算,每冶炼1t钛精矿需要消耗约911.55kWh的能量,云南某公司加料速率为5t钛精矿/h,钛精矿碳热还原,理论上需要消耗约4557.734kWh的电耗.能量支出方面有物料带走的物理热、炉壁和炉顶冷却水热损失、炉底风冷热损失、电力设备热损失以及少量未预见热损失,钛精矿冶炼过程中,能量的输出和输入是基本相等的,热量处于平衡状态.     

热连轧高强钛合金厚壁管道的TIG工艺及组织和性能

针对采用新型的热连轧工艺生产的厚壁高强度无缝钛合金管,通过TIG自动送丝与手工填丝2种焊接方法进行了环缝对接焊工艺试验,对比分析了2种工艺下接头的焊缝成形、微观组织及力学性能。结果表明,2种焊接方法下的焊道表面均呈亮银色,无明显氧化现象,自动送丝接头表面成形更加平滑美观,而手工填丝接头表面成形有不规则的鱼鳞纹;热影响区中β相均发生了一定程度的粗化,并生成了一定量的细针状α’马氏体相。焊缝区组织主要为沿β相界生成的板条状和块状α相,以及晶粒内形成的少量针状α’马氏体组织;TIG自动送丝和手工填丝焊接接头的硬度都是热影响区最高,焊缝最软而母材居中;拉伸试验断裂位置均位于焊缝,平均抗拉强度分别为603.8 MPa和571.7 MPa;热影响区的冲击吸收能量分别达到了41.7 J和78.5 J,手工填丝下的热影响区表现出了比母材更好的冲击韧性。创新点： (1)研究了热连轧工艺下新型钛合金管道手工TIG/自动TIG工艺下的组织及力学性能,2种工艺均采用多层多道焊技术。(2)2种工艺采用纯钛焊丝进行填充时,接头抗拉强度均高于母材;焊缝及热影响区冲击韧性均高于母材;焊缝由于纯钛焊丝合金元素低,冷却下来焊缝位置形成的马氏体含量低。(3)手工TIG/自动TIG多层多道工艺下复杂的热过程起到了合适的热处理作用,热影响区形成了大量重叠交织的α组织,使得热影响区的冲击韧性大幅度提升,解决了该系钛合金常规焊接工艺下热影响区冲击韧性差的问题。     

Low cycle fatigue improvement of powder metallurgy titanium alloy through thermomechanical treatment

A low-cost β type Ti-1.5Fe-6.8Mo-4.8Al-1.2Nd （mass fraction, %）（T12LCC） alloy was produced by blended elemental powder metallurgy（P/M） method and subsequent thermomechanical treatment. Low cycle fatigue（LCF） behavior of P/M T12LCC alloy before and after thermomechanical treatment was studied. The results show that the LCF resistance of P/M titanium alloy is significantly enhanced through the thermomechanical treatment. The mechanisms for the improvement of LCF behavior are attributed to the elimination of residual pores, the microstructure refining and homogenization.     

Laser rapid forming of low cost hydride-dehydride titanium alloy powder

Low cost hydride-dehydride （HDH） Ti-6Al-4V （Ti-64） alloy powder was employed to investigate the metallurgical quality and mechanical properties oflaser formed samples. With appropriate control of the laser forming processing parameters and the loose density of HDH powder, two kinds of defect, i.e. porosity and ill-bonding, can be avoided. Rare earth Nd powder was added to HDH Ti-64 powder to purify laser formed alloy. The results show that with a few additive of Nd, the microstructure of laser formed alloy changes from Widmanstaitten morphology to a basket weave microstructure. Accordingly an appropriate addition of Nd is effective to improve both the strength and ductility of laser formed HDH Ti-64 alloy. The values of tensile test meet the wrought specification with the content of Nd ranging from 0. 1%-0.2%（mass fraction）.