A new metallurgical process of roasting-counter current leaching-acidification-releaching is developed to treat the low grade beryllium concentrate with BeO content of 1.13%. Firstly,the beryllium conc entrate is roasted at 1 050 ℃ for 120 min and the resultant calcine,ground to the particle size less than 0.1 mm,is processed by counter current leaching at 30 ℃ for 60 min with the liquid-solid ratio （i. e. the mass ratio of the returned releaching solution to calcine ） of 4 ： 1 . Then , the counter current leaching residue is acidized at 100 ℃ for 30 min by adding sulfuric acid with the acid ore ratio of 1 ~ 1. Finally, the acidifica- tion residue is releached at 30 ℃ for 60 min by adding water with the liquid-solid ratio of 4 ： 1. Through the above process,the BeO content of the leaching residue decreases to 0.14%,the leaching rate of beryll- ium reaches 88.88% ,and the leaching solution can be used for subsequent beryllium oxide extraction.

The characterization parameters are summarized for performance evaluation of molten salt system in TICl4 molten salt chlorinator, and a preliminary analysis of its influencing factors is carried out. The causes of molten salt system deterioration during TICl4 molten salt chlorination are analyzed based on pro duction practice. According to the causes of molten salt system deterioration and the related factors,control measures for molten salt system stability are presented.

In view of the off-standard contents of the copper,iron and some other impurities in high-purity niobium oxide produced in a company,the causes of the quality accident are analyzed. The results indicate that the nitric acid mixed in hydrofluoric acid can rapidly oxidize 2-octanol into organic acid in extraction process. The resultant organic acid interferes with the acid pickling process of the niobium oxide,resulting in the off-standard impurity （i. e. copper and iron） contents in the product.

Concentration distribution of Nd2O3 in electrolysis cell were studied with self-made multipoint sampling device for high temperature molten salt,and the reason for the regular distribution pattern was analyzed. The results show that concentration of Nd2O3 is always less than 4 % and its vertical distribution is decreasing from top to bottom, in accordance with Nd2O3 consumption near anode in the actual production,while its horizontal distribution is increasing from cathode to anode.

To solve the problems of stockpiling of waste rare earth fluorescent resources, and for the environmental concern and recycling of secondary valuable resources,recovery methods of the waste rare earth fluorescent resources and Hg and RE are emphatically summarized. A new concept of environmental friendly and efficient recovery is proposed,and its prospect is also pointed out.

The latest development is reviewed of radioactive pollution in rare earth production. A detailed description is made of the common radioactive detectors in rare earth production. The future development trend is proposed mainly towards the low-energy ray detection and weak radioactive sample determination in rare earth production.

Various sintering methods are reviewed,including solid phase sintering, spark plasma sintering, microwave sintering, two-step sintering, low-temperature activated sintering, selective laser sintering, stacking sintering and so on. Besides, the problems of these methods are summarized.

The investigation was made of the effect of solid solution-aging process on the microstructure, mechanical properties and tensile fracture morphology at room temperature of TC4 titanium alloy. The results show that through solid solution-aging process, acicular martensite α＇ phase and metastable β phase are broken down into dispersive stable α＋β phase, increasing the hardness and strength of TC4 titanium alloy. When the solid solution temperature is constant,the hardness and strength of the TC4 titanium alloy gradually decrease, while its plasticity gradually increases with the aging temperature increasing. Under the conditions of solid solution temperature 940 ~C and aging temperature 500 ℃, the TC4 titanium alloy can be obtained with higher strength and better plasticity. After solid solution-aging treatment, TC4 titanium alloy has better plasticity at room temperature,and its tensile fracture is characterized by ductile fracture.

A new S/TiO2 composite cathode material was synthesized with elemental sulfur and titanium dioxide. The crystal structure and surface morphology of the composite were characterized by XRD and SEM, and its electrochemical performance was studied by charge-discharge test and electrochemical impedance test. The results show that S/TiO2 composite cathode material with a S/TiO2 mass ratio of 5 ： 1 has good electrochemical performance,with initial discharge specific capacity up to 370 mA · h/g at 0.1C and kept at 290 mA · h/g after 30 cycles.

YAG powders were synthesized with sol-gel combustion method using citric acid, ethanediol and glycine as combustion agents separately,and they were characterized by TG/DTA instrument,XRD and FTIR. The results indicate that citric acid is the most appropriate combustion agent for synthesis of YAG powders with sol-gel combustion method. Because both glycol and glycine need higher crystallization temperature as combustion agents,and YAG powders synthesized with glycine as combustion agent contains intermediate phases of YAM and YAP. When using citric acid as combustion agent, YAG precursor completely converts into pure YAG phase at the critical temperature above 900 ℃. After it calcines at the temperature above 900 ℃ for 2 h,the high-purity YAG powders can be obtained.