Preliminary Analysis of Disposal of Ammonium and Nitrogen from Ammonium Molybdate Production by Ion Exchange

CHEN Zhi-gang

Rare Metals and Cemented Carbides | Vol., Issue 4, 2007 | pp. 31-33

Study is made on the NH3/N balance calculation from ammonium molybdate production by ion exchange. Bench-scale test was done for ammonium removal by heating and alkalization from ammonium- bearing solution during ion exchange. The test results showed that under given technological condition, 99% of NH4-N can be effectively removed from the ammonium solution with waste water discharge up to Class II discharge norms as specified in GB8978--1996.

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Application of Tribromoarsenazo in Photometric Analysis of Rare Earth Elements

YANG Hao-yi;YAN Gao-hua;ZHONG Guo-xiu

Rare Metals and Cemented Carbides | Vol., Issue 4, 2007 | pp. 34-38

The applications of tribromoarsenazo in determination of total rare earth, cerium group and single rare earth elements by spectrophotometry was reviewed in the paper based on the comprehensive analysis of lots of literatures. The spectrophotometry covers absorption photometry, solid photometry,kinetic pho- tometry and calculation photometry, etc.

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Determination of Chlorine in Ta/Nb Composite

YU Hong-yan;JIANG Ning-fen

Rare Metals and Cemented Carbides | Vol., Issue 4, 2007 | pp. 39-41

Analysis is made of the determination of chlorine in tantalum-niobium composite. Chlorine in tan- talum-niobium composite is determined through heating and distillati＇on with high-temperature tubular fur- nace and silver chloride turbidimetry. The results showed that 89.10%-92.5% recovery （with standard specimen） was achieved at relative deviation 6.75% by the said method.

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The Latest Development of Separation of Molybdenum from Tungsten

LIU Xu-heng;SUN Fang;ZHAO Zhong-wei

Rare Metals and Cemented Carbides | Vol., Issue 4, 2007 | pp. 42-45

The latest development of tungsten and molybdenum separation is briefed in this article. The fu- ture research orientation of the tungsten and molybdenum separation is pointed out.

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The Current and Future Research of Oxides Formed in the Course of Thermal Wear of Metal Composites

TIAN Si-guang;YOU Xian-qing;ZHONG Cheng-shan;HUANG Man-ping;MA Jian-guo

Rare Metals and Cemented Carbides | Vol., Issue 4, 2007 | pp. 46-50

The paper summarizes the formation,movement model of the debris and grain,the condition and mechanism of the oxides formation in the course of thermal wear of the metal composites. Analysis is made of specific stage and influence factor of the formation of the oxides glaze layer. Based on the current re- search on oxides glaze layer, future tendency is forecast for the oxides research in the course of thermal wear of the metal composites.

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Research on Grain Growth Inhibitor of the Ultra-fine Cemented Carbides

LIU Shu-zhen

Rare Metals and Cemented Carbides | Vol., Issue 4, 2007 | pp. 51-56

In view of the effect of the grain growing-up inhibitor during ultra-fine cemented carbide produc- tion,description is made of the cause of WC grain growth and inhibition mechanism of the inhibitor during sintering. General.description is made of the type.dosage,way of addition of the carbide and oxide inhibi- tors for transitional metal elements and the current research on the composite inhibitors as well other types of inhibitors such as RE inhibitor, B.P.Cu.Mo and Ru inhibitors. Comparison is done between the inhibi- tion effects.

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Latest Development of Transitional Metal Carbide Additives in Ti(C,N)-based Cermet

ZOU Shi-min;CAO Shun-hua

Rare Metals and Cemented Carbides | Vol., Issue 4, 2007 | pp. 57-60

Description is made of the typical structure of the Ti（C, N）-based cermet, focusing on the influ- ence of the additives of transitional metal carbide, such as nano-crystal TiC/TiN, Mo2C,WC,TaC, NbC, VC,CraC2 on the microstructure and mechanical property of Ti（C,N）-based cermet. It is feasible to pro- duce Ti（C,N）-based cermet with excellent performance by proper addition of carbide additives.

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Application and Development of Titanium Alloys

SHAO Juan

Rare Metals and Cemented Carbides | Vol., Issue 4, 2007 | pp. 61-65

The application and latest development of Ti alloys are reviewed, focusing on the main character- istics,machinability and applications of Ti alloys in aerospace, military industry and automobile industry. The future development of Ti alloys is forecast.

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Preparation and Properties of Ce_0.8Gd_0.2O_2-δ

SHI Qian;ZHENG Feng;CHEN Yu

Rare Metals and Cemented Carbides | Vol., Issue 3, 2007 | pp. 1-4

Ce0.8Gd0.2O2-δ electrolyte for solid oxide fuel cellI （IT-SOFC）δ was prepared by co-precipitation method. Its properties are tested. The XRD measurement shows that the powder from precursor calcination is of mono-cubic fluorite-type structure. SEM testing shows that the calcination temperature has important influence on powder morphology and density of the sintered body,relative density of which reached 96.4% upon sintering at 1 350 ℃. And the results of impedance spectroscopy showed that ionic conduction of the said electrolyte reached 0. 003 S/cm at 700℃.

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Study on Design of Electrolytic Cell System for Ultrasonic Electrooxidation of Molybdenum Concentrate

FU Jian-gang;JIA Li-juan;ZHONG Hong

Rare Metals and Cemented Carbides | Vol., Issue 3, 2007 | pp. 5-9

Electrolytic cell system for ultrasonic electro-oxidation of molybdenite was studied and designed. The preliminary explorative test results show that effective oxidation decomposition of molybdenite concentrate under electric and ultrasonic field can be realized by using new type of agitator-tank electro-chemical reactor（through out-field enhancement by ultrasonic probe, use of high-performance electrode materials, in-cell mechanical agitator and so on）.

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