Study on Direct Concentration of Waste Sulfuric Acid from Titanium Oxide Hydrolysis by Vacuum Membrane Distillation

LI Qian;ZHANG Qi-xiu;ZHANG Gui-qing;ZHOU Kang-gen

Rare Metals and Cemented Carbides | Vol., Issue 3, 2001 | pp. 1-5

The paper described the experiment on the upgrading of TiO 2 hydrolysis waste H 2SO 4.The results show that 18% of TiO 2 hydrolysis waste H 2SO 4 is directly upgraded by VMD only up to 31%～32%concentration(mass%),while the pure H 2SO 4 solution of same concentration can be upgraded by VMD up to 65.5%,and VMD process is affected mostly by FeSO 4.

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Study of Microstructures of Steel-bonded Cemented Carbides from Prealloyed Powder

WANG Che;ZHONG Tao-xing;ZHOU Mei-ling

Rare Metals and Cemented Carbides | Vol., Issue 3, 2001 | pp. 6-9

In this paper are analyzed the effects of carbon on microstructures of steel-bonded cemented carbides from prealloyed powder.Formation of WC and compound carbide is described.The results showed that the amount of WC precipitates is dependant on the carbon content,the addition of 0.6% of carbon black can resutlt in microstructure similar to that of the traditional steel-bonded cemented carbide.

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Investigation on Lowering of Fe,Ni and Cr Impurities Content in Na-reduced Ta Powder

LI Shi-lin

Rare Metals and Cemented Carbides | Vol., Issue 3, 2001 | pp. 10-13

Investigation is made on lowering of Fe,Ni and Cr impurities content in K 2TaF 7 and sodium reduced Ta Powder.The results showed the basic way to lower Fe,Ni and Cr content is by reducing the fusion salt corrosion of the reduction equipment Fe;Ni,and Cr content can be distinctly lowered by the selection of proper fusion salt system and composition,the lowering of initial reduction temperature as well as the melting of given amount of sodium and diluent in the reactor followed by addition of K 2TaF 7 for melting.

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Investigation on Expansion Mechanism of Tungsten Alloy

YIN Xiang-chu;XIONG Xiang-jun

Rare Metals and Cemented Carbides | Vol., Issue 3, 2001 | pp. 14-16

Investigation is made on the improvement of the expansion coefficient of W-Ni-Cu alloy.The results showed that the alloys expansion coefficient varies directly as the binding phase (Ni Cu) and basically conforms with the law of addition.The expansion coefficient of the said alloy has been improved from 5.6×10 -6 /K to 8×10 -6 /K on the prerequisite of ensuring good properties of tungsten alloys by controlling the alloy component,optimum technical conditions.

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A Study on Improving Indium Leaching Rate from Lead Dust

JIANG Xin-yu;ZHOU Chun-shan

Rare Metals and Cemented Carbides | Vol., Issue 3, 2001 | pp. 17-19

The recovery of In from lead dust was investigated.The use of new leaching process by sulfating calcination and water leaching has resulted in leaching rate of In more than 87%.

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Influence of Active Spheroidization Agent on the Morphology of Cobalt Oxalate

GAO Jin;CHEN Qing-lin

Rare Metals and Cemented Carbides | Vol., Issue 3, 2001 | pp. 20-22

Study is made of the influence of active spheroidization agent on the morphology of the cobalt oxalate.Analysis is made of the microstructures of industrial cobalt oxalate and spheroidial cobalt oxalate by X-diffractmeter and their morphology is observed under scanning eletron microscope.The experiment results showed addition of active spheroidization agent can result in distinct morphology change with better physical properties on the prerequisite of unchanged crystalline structure of the cobalt oxalate.

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Catalytic Synthesis of DOP,DOM and DOA with Ln_2O_3/ZrO_2 Catalyst

CHEN Qi-rui;SHAO Ming-xia

Rare Metals and Cemented Carbides | Vol., Issue 3, 2001 | pp. 23-26

The catalytic synthesis of DOP,DOM and DOA with catalyst Ln 2O 3/ZrO 2 (Ln=Nd,Sm,Er),prepared by coprecipitation-calcination method,has resulted in distinct efficiency improvement and due to its larger specific surface area and better dispersion by～60% less carrier Ln 2O 3 consumption compared with pure Ln 2O 3.

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Considerations to be Given in the Study of Metallurgical Reaction Kinetics

SUN Zhao-ming;ZHAO Zhong-wei

Rare Metals and Cemented Carbides | Vol., Issue 3, 2001 | pp. 27-29

According to some documents concerned,this paper has analyzed a few problems liable to be overlooked in the study of metallurgical reaction kinetics,the reasons for the problems occurred.The paper also proposed considerations to be given in the study of metallurgical reaction kinectics.

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Sol-Gel Process and Its Application for Preparation of Metallic Oxide Powder and the Coating

QIN Pei-yu;ZHOU Shi-quan

Rare Metals and Cemented Carbides | Vol., Issue 3, 2001 | pp. 30-33

Three types of Sol-Gel methods used in manufacturing metallic oxides were analyzed in this paper: gelation Sol-Gel method, organo-metal polyment Gel method and organo-polymer Silica-Gel method,their suitable applications were also reviewed.The paper focused on the discussion on powder agglomeration and coating crack propagation during oxide ceramic manufacturing.

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Present Status and Technical Development of China's Cobalt Powder Industry

CHEN Qing-lin

Rare Metals and Cemented Carbides | Vol., Issue 3, 2001 | pp. 34-38

The paper describes the present production status,technical development and quality of cobalt powder.Suggestions are made on the development orientation of cobalt powder production with reference to the foreign cobalt powder production processes and foreign/domestic technical development of the cobalt powder

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