Alumina-doped molybdenum powders were prepared by hydrothermal synthesis combined with low-temperature calcination and two-stage reduction, and mass fraction of Al2O3 were 0,0. 25%,0. 5%, 0.75% and 1% in the molybdenum alloy powders. The morphology and phase composition of molybdenum alloy powders were analyzed using SEM and XRD,respectively. And the influence of A12 Oa dosage on mo- lybdenum alloy powders was investigated at different preparation stages. The results show that Al2O3 dos- age has a certain effect on the uniformity, particle distribution and particle size of the powders. Increasing Al2O3 content has dispersion effect on aggregation of molybdenum alloy powders. After two-stage hydro- gen reduction, flaky MoOa particles is completely reduced to spherical Mo particles,and the mixed powders are mainly composed of Mo and a-Al2O3 without other phases, α-Al2O3 can refine the molybdenum parti- cles ,and the refinement effect of molybdenum particles is more obvious with alumina increasing.

The latest development is reviewed of domestic and foreign studies on rare earth ion substituted strontium ferrites in recent years. The effects are analyzed in detail of simple substitution with single rare earth ion or combined substitution with rare earth ion and transition metal ion on the chemical composi- tion,crystal structure and magnetic properties. And then the application prospect of strontium ferrites ispointed out.

Titanium alloy （TC4） bar rolling process with three-roller Y-typed rolling mill and flat triangle round pass system was simulated by the finite element software of ANSYS/LS-DYNA. The rolling param- eters including metal flow, stress and strain and rolling force were studied. The simulation results show that it is feasible to produce titanium alloy bar with flat triangle-round pass system,providing an analytical reference for rolling program and pass design of new products.

A new type of movable cooling water jacket is introduced,which is used in the large K2TaF7 crys- tallization tank to properly control the cooling crystallization process. By increasing or decreasing the hum ber of cooling water jackets and the cooling water flow rate to control the cooling temperature and time, the morphology and granularity of K2TaF7 crystal can be well controlled,improving the quality and direct re- covery rate of the product.

The extrusion molding technology of cemented carbide is introduced in detail including the devel opment of molding hinder and the production technology and equipment of each procedure. The actual op erating essentials of each step are introduced in detail,and the future development of cemented carbide ex trusion molding technology is pointed out.

Milling of manganese carbonate ore is important for production of electrolytic manganese metal. When manganese carbonate ore is milled in a vertical roller mill in combination with hot air furnace and hot air recycling system and dedusting system, the particle size of 90% manganese carbonate powder product is less than 150μm and its moisture is less than 0.5%. Compared with the traditional milling process for manganese carbonate ore, the above milling process is characterized by lower energy consumption, higher production efficiency, higher automation degree and less floor area. Therefore, this process is of importance for promotion of technological advance and energy saving, with advanced technical index and high economic benefit.

The trace oxygen in refractory metal tungsten, molybdenum, tantalum or niobium was determined by pulsed coulometry,the method to continuously determine a series of samples was set up. The results show that the relative standard deviation is less than 6.7% ,the standard addition recovery is between 95～99% for metal samples with oxygen content under 0. 001%. The above method has been used for deter- mining oxygen in tungsten, molybdenum, tantalum or niobium on site with quick analysis and satisfactory results.

Pure niobium or niobium product is completely transformed into the oxide, which is mixed with the carrier according to a certain proportion,and simultaneous determination of the six elements including Fe,Cr,Ni,Si,Ti and Cu in the sample is carried out by Prodigy DC arc spectrometer made in American Le Mans Company. The precision,accuracy and detection limit of this method can meet the requirements for niobium analysis,its standard addition recovery is 97.5%～101.0% ,and RSD is 3. 352%～6. 255%.

The impacts of production process of nuclear grade zirconium and the chloride on the zirconium alloy ingot were summarized. In view of the chloride affecting the consumable electrode welding and ingot melting in zirconium alloy ingot production,a series of control and prevention measures are put forward so as to improve the safety in production and quality of the zirconium alloy ingot.

CFD software is used to establish 3 kA rare earth electrolytic cell mathematical model of gas-liquid two-phase flow, the anode gas apparent velocity of different depth is calculated via cathode metal generation,and the combination of the anode gas apparent velocity calculation with rare earth electrolytic cell flow field numerical simulation is proposed for the first time. Comparison is made of the anode gas flow field distribution loaded or unloaded with apparent velocity at the anode depth of 0. 250 m, 0. 300 m, 0. 350 m and 0. 395 re,respectively. The results show that in the same coordinates the anode gas velocity loaded with apparent velocity is greater than that unloaded with apparent velocity, the former groove melt has stronger perturbance than the latter,as can provide theoretical basis for the actual operation of RE electrolysis cell flow field.