The present process of oxidation roasting-acid leaching of bastnaesite generates HF waste gas, resulting in a waste of fluorine resource and environment pollution. And meanwhile the process of hydrochloric acid leaching-sodium hydroxide decomposition has the disadvantages of high leaching acidity, large liquidsolid ratio,high leaching temperature and long leaching time. In view of the above problems, a new smelting process of bastnaesite is introduced,namely low temperature activation-cascade acid leaching. Experi- mental results show that bastnaesite can be activated by roasting at 400 ℃ for 2 h. After five-stage cascade acid leaching of the roasted ore,the leaching rate of rare earth carbonate is increased to 98.39% and the leaching rate of rare earth fluoride is reduced down to 0. 014%. The new process is characterized by high u- tilization rate of rare earth resources and fluorine recycling to achieve the objectives of high efficiency,energy-saving and environmental-friendly metallurgy.

Gold, selenium and tellurium were separated from copper-separated residue from copper anode slime by Chlorination leaching,and then the gold was selectively reduced from the leaching solution with ferrous sulfate. The results show that under the optimized conditions of leaching time of 150 min,leaching temperature of 60 ℃ ,sodium chlorate conentration of 65 g/L,the ratio of liquid to solid of 4 ： 1, sodium chloride concentration of 50 g/L, sulfuric acid concentration of 300 g/L, the leaching rates of gold, selenium and tellurium can reach 93.7%, 93.7% and 93.7%, respectively. It is feasible to reduce gold chloric acid from the chloridizing leaching solution with ferrous sulfate,and the reduction rate of gold is 99.7%. In the reduction product, gold exists as elemental gold, almost without elemental selenium, elemental tellurium and other impurities.

Investigation was made of selective extraction of rare earths from the acid leaching solution of spent nickel-metal hydride batteries by solvent extraction. A suitable extraction system was established. Study was made of the effects of the factors such as the initial pH value of raw material liquid, extraction temperature, mixing intensity, extraction time, extraction phase ratio on the extraction efficiency, as well as the effects of such factors as the stripping agent composition and concentration, and stripping phase ratio on the stripping efficiency. In addition, the extraction isotherm of rare earths was measured. Based on the research, pilot-plant experiment was conducted. The results show that the extraction rate of rare earths can reach 99.99 % by five-stage countercurrent extraction. Through the precipitation of the mixed stripping solution with oxalic acid,the rare earths with a purity of 98.49% can be obtained and the contents of all the metallic impurities are less than 0.05 %. The chosen extraction organic phase has a good selectivity for rare earths to ensure the separation of rare earths from other elements.

According to the principle of simultaneous equilibrium and the law of mass conservation, thermodynamic equilibrium diagrams of Ca-V（V ）-H2O system were established with different concentrations of total free calcium at 25 ℃, and then thermodynamic analysis was made of the system. The results show that the six stable solid regions of V2O5 ,Ca（VO3）2, Ca2V207 ,Ca3 （VO4）2 ,CaB （VO4）2 ＋Ca（OH）2 and Ca（OH）2 appear in turn with increase of the system pH value. When total free calcium concentration is 0.01 mol/L in the equilibrium system,at the pH region of 5.1-9.8,vanadium is precipitated in the form of Ca（VO3）2 and vanadium concentration can be reduced to 2.2× 10^-3 mol/L. At pH region of 9.8-10.3, Ca2 V2 O7 is formed and corresponding vanadium concentration can be decreased to 1.2 × 10 ^-2 mol/L. At the pH region of 10.3-12.6 ,Ca3 （VO4）2 is precipitated and the minimum vanadium concentration can reach to 2.4 × 10^-4 mol/L, which is the best vanadium precipitation effect. When total free calcium concentration is 0.01-1.0 mol/L,theoretical optimum pH value for vanadium precipitation is kept at about 11.0-12.6.

A horizontal fluidized-bed roaster is researched and designed based on the roasting characteristics of molybdenite concentrate and V-containing carbonaceous shale. And the problem is solved of application limitation of traditional fluidization roaster.

In view of the technical difficulty of the control of the chemical composition uniformity of Zr-4 in- got after C addition,study was made of the addition modes of alloying elements and smelting process parameters on ingot composition uniformity. The results show that the distribution of C element in the ingot can be controlled in the ideal state,only by adding C element in the form of intermediate alloy to produce Zr-4 ingot with the conventional smelting process.

The strontium germinate crystal nanowires were prepared by hydrothermal method, and their photocatalytic performance for degrading gentian violet was investigated. The results show that the degradation rate of gentian violet increases by prolonging the photocatalysis time and increasing the dosage of strontium germinate crystal nanowires, but gradually decreases with the increase of initial concentration of gentian violet solution. Under the conditions of photocatalysis time of 4 h, strontium germinate nanowires dosage of 10 mg and initial concentration of gentian violet solution of 10 mg/L,the optimal photocatalytic effect of the strontium germinate nanowires for degrading gentian violet can be obtained, with a degrada- tion rate of 89. 59%.

The polycrystalline yttrium aluminum garnet （YAG） fibers were prepared with sol-gel method. The investigations were made of the viscosity, spinnability,infrared absorption characteristics and thermal decomposition properties of the YAG sol. Meanwhile, the phase structure and microstructure of the YAG fiber were analyzed. The results show that the spinnability of the YAG sol is the best when the solid content of the sol is 26%-28% and the spinning temperature is 20 ℃ There are lots of hydroxyl groups of Al-OH and Y-OH exsiting in the YAG sol,and the two kinds of hydroxyl groups can be condensed to form macromolecular chains by losing H2 O, macroscopically exhibiting the spinnability. Weight-loss of the YAG sol mainlY occurs below 600 ℃ in the thermal decomposition process. The YAG fibers with pure phase can be obtained with sol-gel method. The YAG fiber grains grow up gradually as the calcination tem- perature and time increase, resulting in the quantity and size increase of the holes among grains and property degradation of YAG fiber.

Five-layer YBa2Cu3O7-δ film was prepared on LaAlO3 single crystal substrate by TFA-MOD, with total film thickness of 1 μm,critical current density （Jc） of 1.6 MA/cm^2 and critical current （L） of 160 A/cm. The Jc values of single-layer film and three-layer film are 3.5 MA/cm^2 and 1.75 MA/cm^2 ,respectively. No cracks and obvious pores are observed in cross-sectional TEM images of three-layer film and five-layer film, and interfaces among the layers are smooth. With the increase of film thickness, critical current density decreases ,probably caused by film performance degradation.

Investigation was made of the continuous cooling transformation （CCT） curves of the weathering steels with Nb and without Nb by Gleeble-1500D thermal simulator,and the influences were analyzed of the Nb element and cooling rate on CCT curve and microstructure changing law. The results show that the addition of Nb inhibits phase transformation of the weathering steel and decreases its phase transformation temperature,causing CCT curve to move to the lower right. Under the condition of cooling rate 15 ℃/s,the microstructure of the weathering steel with Nb significantly changes. With the increase of cooling rate, the hardness of the weathering steel with Nb increases gradually. Lots of bainite forms at the cooling rate of above 5 ℃/s,and some martensite forms at the cooling rate of over 20 ℃/s,which is good for strength and performance improvement of the weathering steel.