四氯化钛铝粉除钒工艺配置

阐述了四氯化钛铝粉除钒工艺、设备配置及其优势,指出铝粉除钒的不足是除钒浆料的间歇性生产,提出通过减小反应器产能来解决的可行性和先进性。     

我国四氯化钛生产工艺的技术进步

介绍了沸腾氯化技术和熔盐氯化技术制取粗TiCl4的工艺流程、工艺参数及矿物油除钒精制TiCl4工艺所取得的技术进步。指出了沸腾氯化技术中存在的主要问题及提高熔盐氯化生产能力的措施，并就这2种工艺特点进行了详细对比。我国具有矿物油除钒精制TiCl4工艺的自主知识产权，取得了多项技术进步，包括热交换节能措施、多个反应罐串联运行和强制循环外加热技术。最后分析了矿物油除钒工艺对海绵钛产品质量的影响。     

沉降在四氯化钛生产中的作用

本实验仔细研究泥浆的物理特性，用化整为零的静态沉降方法，产生不含不溶物的优质粗四氯化钛，满足下一道工序的需要。本方法能随时将不溶物清除，防止了不溶物进入系统循环。有效地利用本方法，可以避免泥浆给生产带来的诸多不利。     

Pressure leaching of converter vanadium slag with waste titanium dioxide

The process of pressure leaching the converter vanadium slag with waste titanium dioxide without roasting was studied. Mineralogy analysis indicates that the converter vanadium slag contains mainly three mineral phases: magnetite, titanium magnetite, and silicate phase. Vanadium is in combination with iron, titanium, manganese, aluminum, and silicon. The impacts of leaching temperature, leaching time, stirring speed, liquid-to-solid ratio, and initial leaching agent concentration were investigated on the waste titanium dioxide leaching process. The results indicate that under the optimal conditions, the vanadium and the iron leaching rates are 96.85 % and 93.50 %, respectively, and the content of titanium is 12.6 % in the residue. The main mineral phases for the residues under the optimal operation conditions are quartz, ilmenite, anatase, and silicate phase, and the residues can be reused as the extraction of titanium raw materials for titanium dioxide production technology by the sulfate method.     

2007年中国四氯化钛市场分析及2008年展望

回顾和分析了2007年中国四氯化钛市场的走势，指出了影响2007年四氯化钛的各种因素，并对2008的市场做出了初步预测。影响2007年四氯化钛的主要因素有海绵钛的需求，新增四氯化钛产能的影响，地理位置和运输成本的影响，环保整顿和环保成本的影响，原料价格和供应情况等。截止2007年底，四氯化钛产能已经达到35．9Х10^4 t／a，已经处于过剩状态。因此，我国2008年四氧化钛市场形势不容乐观。     

Gas-Phase Production of Titanium Nitride and Carbide Powders

The Bureau of Mines investigated a procedure to produce fine-sized titanium nitride, carbide, and carbonitride powders. These powders, because of their high hardness and abrasion resistance, can be substituted for tungsten carbide in some cutting tool applications. Titanium nitride and carbide powders can be cemented together with nickel. The investigated approach produces titanium nitride by reducing titanium tetrachloride with magnesium or sodium vapor in a nitrogen atmosphere at temperatures between 750 and 1,050°C (1,382 and 1,922°F). Titanium carbide and titanium carbonitride can be formed by adding methane to the nitrogen atmosphere. Titanium tetrachloride reduction efficiencies as high as 98% are achieved. X-ray diffraction analyses showed that the powders contain no major impurities. Because the reactions occur in the gas phase, powders finer than 1 μm are produced.     

Influence of Vanadium Element on Microstructure of Electron Beam Welded Titanium Alloy to Stainless Steel Joint

Electron beam welding experiments of titanium alloys with different vanadium content to stainless steel,as well as alpha titanium to stainless steel using vanadium sheets as filler metal and transition portion were carried out.Microstructures of the joints were examined by scanning electron microscope.The properties were evaluated by microhardness and tensile strength.It was shown that electron beam welding is not feasible due to the brittle Ti-Fe intermetallics with high hardness.Increase of vanadium content in base metal can restrain but can’t avoid the formation of cracks.When vanadium content was too large,the joint was embrittled by FeTi compound with supersaturated V and also cracked after welding.Crack free joint was achieved by using vanadium transition portion which can prevent the contact of Ti and Fe elements.However,the formation of brittle σ intermetallics reduced the tensile strength of the joint,only up to 134MPa.     

利用固体透氧膜提取海绵钛的新技术

对克劳尔法、电解四氯化钛法等海绵钛传统生产方法以及在熔融CaCl2中直接电解还原二氧化钛制取钛的新工艺进行了总结和分析。针对这些方法中存在的不足,提出了一种利用固体透氧膜技术直接从含钛氧化物矿制备海绵钛的连续、低成本、无污染的绿色冶金新工艺。     

Molecular theory of adsorption in meso- and macropores and Kelvin equation

The molecular theory of adsorption is used to estimate the upper bound of the validity of the Kelvin equation for calculating the saturated vapor pressure in meso- and macroporous adsorbents. The values of saturated vapor pressure are compared according to the theoretical adsorption isotherms obtained in terms of the lattice gas model and the Kelvin equation for atoms of argon and molecules of nitrogen and tetrachloride carbon. As the temperature increases, the agreement between the two methods improves. It is shown that the validity of the results obtained using the Kelvin equation for problems of absorption porometry is even limited for pores as small as 50 nm.     

钒钛微合金化对铸态中锰钢组织和性能的影响

通过试验研究,探讨添加钒钛微合金化对铸态中锰钢的组织性能的影响,确定钒钛微合金的合适加入量,实验表明经添加V质量分数为0．1％。0．2％或Ti0．15％与稀土和硅钙合金的复合处理后的铸态中锰钢,在中低冲击载荷下耐磨性能优于高锰钢,实现铸态中锰钢在中低冲击载荷下使用具有良好的耐磨性,该项目的研究具有良好的经济与社会效益。     

钒酸盐缓蚀剂的有效氧化态及其在致钝过程中的速度控制步骤

作者在下列腐蚀体系中:(1)000 Cr17Ti 不锈钢在 H_2SO_4溶液中,(2)碳钢在一乙醇胺溶液中和(3)TC4钛合金在 H_2SO_4溶液中,用旋转电极电位滴定法研究了钒酸盐缓蚀剂的有效氧化态。结果发现,钒酸盐缓蚀剂的有效氧化态是+5,且各种五价钒化合物之间是等效的。通过钒酸盐临界致钝浓度与旋转圆盘电极转速关系的研究,作者确定了:(1)钛合金的致钝过程是由钒酸盐向钛合金电极表面的扩散过程所控制;(2)钒酸盐在钛合金表面进行的阴极反应中获得的电子数为1。     

熔盐电解法生产海绵钛的回顾和新技术开发

回顾了熔盐电解法生产海绵钛的研究 ,介绍了熔盐电解TiCl4生产海绵钛的工艺过程 ,重点提出一项在熔融CaCl2 中直接电解还原TiO2 生产海绵钛的新工艺。     

低铬钒钛铸铁铁型的试制及应用

利用承德钢铁集团公司特有的钒钛资源优势,开发了低铬钒钛铸铁铁型,其高温下的力学性能大为增强,抗熔蚀、抗激冷激热、抗氧化生长性能显著提高,使用寿命远优于同行业同类产品。     

钒钛合金冷硬铸铁轧辊试验研究

钒钛合金冷硬铸铁轧辊生产试验表明,在碳当量ＣＥ＝３．９９％时,０．２８％Ｖ;０．０７％Ｔｉ;０．７６％Ｃｕ,其合金化作用可使冷硬铸铁轧辊获得较为理想的力学性能与耐磨性能。     

Effects of vanadium and titanium on mechanical properties of low carbon as cast microalloyed steels

Abstract

Tensile, hardness and room temperature Charpy V notch impact tests were conducted to evaluate the variations in the mechanical properties of a low carbon cast steel containing vanadium and combinations of vanadium and titanium in the as cast condition. Tensile and hardness test results indicated that good combinations of strength and ductility can be achieved by microalloying additions. The effect of titanium on the yield strength and hardness, however, strongly depended on Ti/N ratio. Ti in hyperstoichiometric amounts increased the yield strength and hardness whereas in hypostoichiometric amounts, it did not have a considerable effect on those properties. Scanning electron microscopy and optical microscopy studies revealed that coarse TiN particles were responsible for this behaviour. On the other hand, microalloying additions significantly decreased the room temperature impact energy and led to the dominance of cleavage facets on the fracture surfaces. Although coarse TiN particles were identified to act as cleavage nucleation sites in the Ti bearing heats, no distinct microstructural feature could be identified as cleavage initiators in the microstructure of the alloy containing only vanadium.     

Kinetic modeling of adsorption of vanadium and iron from acid solution through ion exchange resins

This study assessed the adsorption process and the reaction kinetics involved in the selective recovery of vanadium from an acid solution containing iron as an impurity. Four commercial resins were studied: Lewatit® MonoPlus TP 209 XL, Lewatit® TP 207, Dowex? M4195 (chelating resin) and Lewatit® MonoPlus S 200 H (strong cationic exchange resin). To investigate the effect of time on the adsorption process, batch experiments were carried out using the following initial conditions: pH 2.0, 298 K, and a proportion of 1 g of resin to 50 mL of solution. The variation of pH over time was analyzed. Chelating resin released less H⁺ ions as the adsorption occurred, resulting in a lower drop of pH when compared to S 200 H resin. Ion adsorption by the resins was also evaluated through FT-IR and SEM?EDS before and after the experiments. Among the evaluated kinetic models (pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion models), the pseudo-second order model best fits the experimental data of the adsorption of vanadium and iron by all of the four resins. M4195 resin showed the highest recovery of vanadium and the lowest adsorption of iron. Kinetic data, which are fundamental to industrial processes applications, are provided.     

Behavior of vanadium during reduction and smelting of vanadium titanomagnetite metallized pellets

The effects of CaO content, MgO content and smelting temperature on the vanadium behavior during the smelting of vanadium titanomagnetite metallized pellets were investigated. The thermodynamics of reduction and distribution of vanadium was analyzed and the high-temperature smelting experiments were carried out. The thermodynamic calculations show that the distribution ratio of vanadium between the slag and the hot metal decreases with the increments of CaO and MgO content in the slag as well as the increase of the smelting temperature. The smelting experiments demonstrate that the vanadium content in iron and the recovery rate of vanadium in pig iron increase as the CaO content, MgO content and smelting temperature increase, whereas the vanadium distribution ratio between the slag and iron tends to decrease. Moreover, the recovery rate of vanadium in pig iron has a rising trend with increasing the optical basicity of the slag. The addition of MgO in the slag to increase the slag optical basicity can not only improve the vanadium reduction but also promote the formation of magnesium-containing anosovite, which is beneficial to following titanium extraction.     

Appropriate titanium slag composition during smelting of vanadium titanomagnetite metallized pellets

The suitable titanium slag composition with high titanium content for electric furnace smelting of vanadium titanomagnetite was investigated through thermodynamics and related phase diagram analysis. According to the thermodynamic results, low-melting-point regions and MgTi₂O₅ primary phase area in the phase diagrams, the suggested titanium slag composition for the present vanadium titanomagnetite metallized pellets should consist of 50% TiO₂, 8%–12% MgO and 13% Al₂O₃ (mass fraction) with a binary basicity of 0.8–1.2. Finally, the verified smelting experiments were conducted and successful separation of the molten iron from the titanium slag is obtained. The obtained vanadium-containing molten iron contains 0.681% V and 0.267% Ti, and the obtained titanium slag contains 52.21% TiO₂ (mass fraction), in which MgTi₂O₅ is the primary phase. The titanium resource in the final titanium slag production could be used to produce TiO₂ pigment by acid leaching methods.     

Structural Titanium Alloys in Modern Mechanical Engineering

Mechanical and process properties of widely used domestic structural titanium pseudo-α-alloys are studied. The Ti – Al – Mn system is chosen as a base for creating commercial titanium alloys of series OT4-0, OT4-1, OT4, etc. The developed titanium alloys guarantee ultimate rupture strength of 600 – 1100 MPa and possess satisfactory ductility in cold and hot plastic deformation. Experience in the use of alloys of this class in the aircraft and spacecraft industries is analyzed. In order to meet the international unification of titanium alloys the possibility of replacing manganese in pseudo-a-titanium alloys by vanadium is studied and documentation for realizing this replacement is created.     

Synthesis of titanium nano-particles via chemical vapor condensation processing

In the present study, titanium nano-particles have been synthesized using chemical vapor condensation (CVC) process. Reaction of sodium and titanium tetrachloride vapors in the tube furnace resulted in the production of titanium nano-particles that were encapsulated in sodium chloride. Dried Argon gas was employed as a carrying agent. Titanium nano-particles were contained in an ethanol bath. Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) were employed for analysis and characterization of nano-particles. The size of primary particles was smaller than 100 nm and secondary particles were submicron agglomerations.