Advanced Materials Research Vols. 1033-1034

Abstract: In this study, an electrodeposited alumina-forming Ni-Al composite having a nanocrystalline Ni matrix dispersing Al microparticles was produced and annealed in vacuum at 500°C for different time (3hr, 5hr and 8hr, respectively). Effect of annealing time on the microstructure, isothermal and cyclic oxidation behavior of the Ni-Al composite at 1000°C was comparably investigated. The results indicated that Al microparticles slowly dissolved into nickel grain to form an ultrafine-grained Ni₃Al/NiAl composite with micro-sized pores dispersion due to volume shrinkage. The increased distribution uniformity of Al with the increasing of annealing time favors the formation of a protective alumina layer in a short time, and then significantly reduced the isothermal oxidation rate. Besides, the reduction of pores size with the increasing of annealing time also helps the ultrafine-grained Ni₃Al/NiAl composite to grow an adherent alumina scale with increased cyclic oxidation resistance.

Abstract: The chemistry of the dissolution of Palladium in pressure-cyanide has not received considerable attention. At room temperature and pressures, the reaction between sodium cyanide and Palladium does not occur because of poor kinetics. However, at elevated temperatures between 100-160 °C, Palladium can be leached by sodium cyanide like the reaction of gold. A research study has been undertaken to develop the fundamentals of a method for the direct dissolution of Palladium In this work, the dissolution of Palladium powder and place were measured in pressure clear cyanide solution. The cyanide leaching reaction mechanism is also discussed. The data of Palladium powder and place at different cyanide concentrations, different temperature and different oxygen pressure are obtained. The dissolution rate of metal Palladium powder and place were found to be relate to the cyanide and oxygen level.

Abstract: The copper extraction yield from chemical leaching of chalcopyrite depends on temperature, pH, and the oxidation-reduction potential (ORP), as well as on the different genetic type of the chalcopyrite used. The chemical leaching characteristics of chalcopyrite from marine volcanic type and porphyry type were studied. It was found that the intermediates of marine volcanic chalcopyrite and porphyry chalcopyrite elucidated from the MLA were elemental sulphur and non-stoichiometric minerals, such as Cu_3.5Fe₄S_2.5, Cu₅Fe₄S and Cu_3.5Fe_1.5S₅. The results suggested that the main difference between marine volcanic chalcopyrite and porphyry chalcopyrite is the rates of copper and iron ions dissolution from chalcopyrite crystal lattice.

Abstract: Breakout is the most detrimental event associated with the continuous casting process, with the overview of the breakout prevention system, a lot of valuable things had been acquired. For breakout prevention, the embedded thermocouples had been proved best for breakout signals detecting. But in china, the system which used well in foreign countries did not fit for the current local condition, and gives error reports more often, so developing an efficient breakout system which fit for the condition of nowadays in China becomes more and more urgently.

Abstract: The paper analyses the manufacturability and difficulties in weld repairs of the electroslag casting red copper crucible with bent axle, work out the relevant measure. It is proved by experiment that large red copper product can be perfectly repairs by use suitable welding procedure.

Abstract: The generating pathways of hydrogen chloride in blast furnace smelting process may have two pathways: 1.sodium chloride and water react with phosphorus pentaoxide forming hydrogen chloride gas.2. Sodium chloride and water react with sulfur dioxide and nitrogen dioxide forming hydrogen chloride gas. Based on Thermodynamic calculation of hydrogen chloride generation in blast furnace smelting process, hydrogen chloride gas is generated in the upper part of blast furnace shaft ,the generating temperature main range from 300°C too 800°C.

Abstract: Repeated experiments were done to study of influence of sensitization process on quality of mixed loading emulsion explosive, the results show that: The ratio of the sensitizing agent at 1:10 ~1:30 are more appropriate; the density of mixed loading emulsion explosive is gradually decreased while concentration of sensitizing agent increased. Emulsion explosive quality is affected by foaming time under the condition of the certain proportion of sensitizer and constant temperature, when the sensitizer mixing time extended to a certain value, the density tends to be stable. Under the condition of invariable sensitizer concentration, proper temperature not only obtain good blasting effect, but also improve the charging efficiency and shorten the charging time; the temperature between 30~50 °C is more appropriate when the ratio of sensitizer is certain.

Abstract: Because of the extraction difficulties from brines in China, it is necessary to take advantage of the lepidolite resources, driven by the huge economic benefit and social benefit requirements. Several factories use refined lepidolite to produce lithium carbonate in Yichun city because of the rare metals and high price of battery-grade lithium carbonate. The primary separation of lepidolite from complex silicate minerals is froth flotation. In this paper, the froth flotation process for production of refined lepidolite from Ta & Nb waste minerals in Yichun city and in Yifeng town is discussed.

Abstract: Heat transfer of the mould flux between the mould and the strand is very complicated, especially for the high carbon steel thin slab continuous casting. In this research the orthogonal experiment has been carried out, and the results showed that: the effect for the heat flux form strong to weak is: R>Na₂O>F>MgO>BaO. and in the experiment range, with the R increasing, when the R, Na₂O content and the F^- content are increasing, the heat flux would be decreasing; with the MgO content increasing, the crystallization temperature would getting fluctuant; with the BaO content increasing, the heat flux would getting fluctuant, when its content is around 6%, the heat flux is reach its summit.

Abstract: Regarding the cylinder piston ring friction pair system as the object , put forward a new numerical simulation method to study the thermal effect mechanism of single pulse interval laser micro texturing. By means of numerical simulation and experimental verification, analysis the variation of laser pulse frequency and laser power on the 45# steel surface micro cavity morphology. The simulation and experimental results show that along with the increase of laser pulse number, the depth of micro cavity increases, the recasting phenomenon of molten metal is obvious, and the machined surface quality decreases. At the same condition, the micro cavity depth simulation results and experimental results are basically the same trend; the maximum error is less than 8%, which proves the feasibility and validity of the numerical simulation method.