滴定法测定冶金产品五氧化二钒中V_2O_3

经溶解、过滤、洗涤等条件及共存离子干扰影响等试验 ,提出测定五氧化二钒产品中三价钒量的容量法 ,结果满意。     

V2O5和V2O3生产钒铁工艺探讨

介绍了攀宏公司钒铁生产技术及工艺标况，对以V2O5和V2O3为原料冶炼钒铁的工艺作了简要分析，介绍。     

由三氧化二钒制备碳氮化钒的研究

以V2O3为原料，采用真空还原方法制备出碳化钒，生成的碳化钒直接进行渗氮制备出碳氮化钒，结果表明，原料中的配碳量是控制反应产物中氮含量的关键因素。氮化温度影响产物中氮含量，低温条件下，随氮化温度提高氮含量增加，但当反应温度高到一定程度，氮含量不再随温度提高而增加，氮化温度在1400℃时，4h可以氮化完全。     

V2O3、Al2O3添加剂对碳化铁生成的影响

在1 023 K用热重法结合XRD分析,研究了V2O3、Al2O3添加剂对混合气体(H2 CHI)还原铁矿石制备碳化铁的影响.研究表明:V2O3对还原反应和碳化反应均有明显的促进作用,有利于提高碳化铁的生成率和稳定性.当V2O3含量在1%以内时,随着V2O3的增加,铁矿石还原速率逐渐加快,碳化速率也提高,促进效果明显;当V2O3含量高于1%,试样还原速率和碳化速率均比1%时略小.Al2O3对还原和碳化有一定的促进作用,但对碳化铁的稳定性有不利的影响.     

镁阿隆-钛酸铝复合材料抗Al2O3附着的研究

利用镁阿隆—钛酸铝复合材料与熔渣和钢水润湿性较小的性能 ,并与Al2 O3 -C和CaO·ZrO2 -C材料作对比试验 ,研究镁阿隆—钛酸铝复合材料抗Al2 O3 的附着作用。结果表明 :镁阿隆—钛酸铝复合材料具有很好的抗侵蚀性和抗Al2 O3 附着性 ,是理想的防堵塞和非污染浸入式水口的内衬材料。     

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High vanadium ferrovanadium was smelted with mixture of V2O5 and V2O3 as raw material, Al-Ca-Fe alloy as refine agent, and its technological parameters were investigated. The optimum conditions are defined: the amount of aluminium is 103% theoretical amount, the addition of refine agent is 100g, the refining time is 30min, and the recovery of high vanadium ferrovanadium is 98%. The optimum addition of refine agent is 100g. If the addition of refine agent is bigger than the optimum addition, the amount of Al in high vanadium ferrovanadium is increased with the refine agent increasing.     

V2O3系PTC陶瓷材料的研究进展

PTC陶瓷材料是一种在基础科学和应用领域有着极为广泛用途的电子材料,可被用于自动调节加热器、温度传感器、保护和延时开关等工业产品.与其他PTC陶瓷材料相比,V2O3系PTC陶瓷材料在常态下有比较低的电导率和大的通流能力,其PTC效应来源于金属-绝缘体相变诱发的体效应,相变中没有晶体结构的变化,可用作过电流保护.通过改变掺杂浓度、温度、压力等因素,V2O3系PTC陶瓷材料会发生顺磁金属相和顺磁绝缘相的相变,这被认为是一个典型的由电子强关联作用引起的莫特转变,因此V2O3系PTC陶瓷材料可以为许多理论模型和实验手段提供一个检验平台.相对于其他PTC材料,V2O3系陶瓷材料的PTC效应来源于一种体效应,其PTC特性不受电压和频率的影响.由于相变过程中有电导的变化,可以作为导电材料来改善高温下锂离子电池的安全性能.简单介绍了PTC陶瓷材料的研究背景及分类,总结了V2O3系PTC陶瓷材料的产生机制、主要特点、影响因素和制备方法,并展望了V2O3系PTC陶瓷材料的应用前景及发展趋势.     

Thermodynamic properties of the V2O3−V4O7 system at temperatures from 1400° to 1700°K

Phase equilibria in the V₂O₃−V₄O₇ system were studied at 1400°, 1500°, 1600°, and 1700°K by varying the oxygen partial pressure. Besides the three phases of V₂O₃, V₃O₅, and V₄O₇ which were stable in this system, the vanadium sesquioxide has an extensive range of solid solution at the above mentioned temperatures. The standard free energies of oxidation of both V₂O₃ to V₃O₅ and V₃O₅ to V₄O₇ were precisely determined on the basis of equilibrium oxygen partial pressures at each above temperature. The standard enthalpy and the entropy changes of these reactions were also calculated from the free energy data.     

Influence of V2O5 Addition on Reduction of NO by C3H6 over Pt/V2O5/Al2O3 Monolithic Catalyst

Pt/V2O5/Al2O3 and Pt/Al2O3 monolithic catalysts were prepared by wet impregnation method, and the influence of V2 O5 addition on the catalytic activity for NO reduction by C3 H6 under lean burn condition was investigated in detail.The results show that Pt/V2O5/Al2O3 has better activity of NO reduction than Pt/Al2O3 , adding V2O5 to Pt catalyst makes the temperature window of NO reduction shift further to a lower temperature region.The activity of NO reduction decreases and there is a similar degree of deactivation over the two catalysts in the presence of SO2 in feed gas.Moreover, adding V2 O5 to Pt catalyst resulted in improvement of resistance to SO2 oxidation, which decreases the emission of sulfate particulate.Thermal aging treatment counteractes the promoting effect of V2O5 on NO reduction.     

用三氧化二钒制取氮化钒试验研究

对三氧化二钒用碳还原氮化制备氮化钒的反应过程进行了热力学与动力学条件分析,在此基础上,对承钢公司氮化钒车间制成的球团料进试验,研究了三氧化二钒用碳热还原氮化温度和时间的关系,并确定了最佳的反应温度和时间,为生产提供理论指导。     

Crystal-field levels of Nd3+ in a new langasite compound Nd3CrGe3Be2O14

We report on the crystal-field (CF) levels of Nd³⁺ in Nd₃CrGe₃Be₂O₁₄, a representative of recently synthesized Be-containing langasites. They are the first in the family to contain two magnetic subsystems, 1D chromium and Kagome-like rare-earth ones. High-resolution broad-band temperature-dependent spectra allow us to find all five CF Kramers doublets of the ground ⁴I_9/2 CF multiplet and 38 levels of the excited ⁴I_{11/2, 13/2, 15/2}, ⁴F_3/2, ⁴F_5/2 + ²H_9/2, ⁴F_7/2 + ⁴S_3/2 and ⁴F_9/2 CF multiplets. These data form a basis for a future exploration of this interesting two-sublattice magnet with frustrated interactions. Optical transitions between Kramers doublets of Nd³⁺ indicate magnetic activity of 1D-chromium chains at T < 20 K.