Advanced Materials Research Vols. 915-916

Abstract: As an effective method for increase extraction efficiency and selectivity,synergistic extraction has been studied for many years because the theoretical and applicative importance. Using synergistic effect of two extractants, distribution ratios of their mixture can be obviously enhanced than those of their individual contributions. Separation of nickel and cobalt for bioleaching solution were studied using a synergistic extraction system with P507 andCyanex272. The test results indicate that the system has better extraction effect. Contrasts the separation effect on nickel and cobalt using three extraction systems of P507, Cyanex272, P507-Cyanex272. Identified during the initial pH value of 1.5-2.2, balance pH value under the condition of 4.0-5.0,synergistic extraction system of P507-Cyanex272 have a good separation effect of nickel and cobalt. The extraction kinetics was investigated using a constant interfacial cell with laminar flow. The effects of temperature, extractant and cobalt concentration were studied. Co extraction rate was compared in the different extraction systems of individual P507 and synergistic P507-Cyanex272 .The results indicated that the extraction apparent action energy in synergistic system was lower than that of signal P507.The separation factor of nickel and cobalt was increased in synergistic system.

Abstract: According to the structural features of the vertical preheater, the 2-dimention finite element models are set up for the section of the preheater with different arrangement and diameters for the limestone grains. The situation of gas-solid two-phase flow between the limestone grains and the hot air in the preheater is simulated by the discrete particle model. Based on the heat transfer theory, the convection heat transfer coefficient between the limestone grains and the hot air is deduced by means of the experimental correlation of the air cross-flow tube bundles. On the simulation of the 2-dimention finite element model of the vertical preheater based on the FLOTRAN module of ANSYS, the temperature field, pressure field and velocity field of the limestone grains are obtained. The results show that there is a little change of convection heat transfer coefficient by varying the arrangement of limestone grains. The convection heat transfer coefficient is improved by employing the limestone grains with little diameter. The larger the gap between the grains is, the larger the convection heat transfer coefficient is.

Abstract: The problems of high falsesieving rate and low productivity are encountered while sieving shelled buckwheat with traditional round plate sieve. This paper presents a design idea for improving the sieving effect by changing the plate structure. The improved designs consist of a round plate sieve with larger percentage of sieving area than the traditional round plate sieve and a triangular plate sieve with the approximately same geometry as shelled buckwheat grains. Tests are conducted to compare the sieving performance of traditional round plate sieve with the newly designed round plate sieve with different percentage of sieving areas and apertures. Also the traditional round plate sieve is compared with triangle plate sieve with different percentage of sieving areas and apertures. Compared to traditional round plate sieve, the falsesieving rate for newly designed round plate sieve with an aperture isφ4.4mm is reduced by 3.6.A round plate sieve with a percentage of sieving area of59.7%, aperture ofφ4.3mm, is used to sieve the shelled buckwheat of sizeφ4.6~4.7mm.A falsesieving rate of2.3, and non-sieving rate of17.4 are obtained and the sieving effect is found to be the best. For the triangle plate sieve a falsesieving rate of90.2 and non-sieving rate of92.1 are obtained. The triangle plate sieve is found unsuitable for the sieving of shelled buckwheat.

Abstract: Engineering analysis and simulation are time-consuming, and often trapped to computational burden, such as analyzing forging press. We herein employ surrogate modeling to reduce such computation cost while keeping high precision. This paper use a BP neural networks to building the surrogate model (BPNN-SM for short), and predicting the analysis results of mechanical structures with this model. The predicting process include confining design variables, sampling, building finite element model with business software ANSYS, constructing surrogate model to replace the original model and finally predicting data with the new model. In such process, we build a back-propagation neural network, and train it with sampling data from ANSYS results. We tested our methods with a mechanical structure design of hydraulic forging press. The experimental results verified the surrogate modeling.

Abstract: The fracture reasons of 500kV high-voltage disconnectors hoops were analyzed. The fracture appearance, composition of chemical elements, metallographic, mechanical properties of the fractured hoops were investigated by ICP-AES, SEM, optical microscope, brinell hardness tester, universal testing machine. The test results that one reason is substandard products of this batch hoop. The composition of chemical elements and mechanical properties is fails to comply with applicable standards prescribed and the casting defects are found. Another reason is that the large pre-tightening force and tightens reverse order.

Abstract: Drill steel is a special steel specifically tailored for drilling rods. To understand the microstructure properties and dimensional accuracy of the drill steel, a rigid plastic finite element method was used to analysis Mannesmann piercing in steel drilling production. The three-dimensional thermal force coupling FEM models were computer generated with different feed angle. The metal deformation during the piercing process was analyzed in detail. The influence of feed angle on deformation, force, velocity and strain was obtained through simulations.

Abstract: Selective Laser Sintering (SLS) has been successfully and broadly applied in biomedical engineering to fabricated biomedical part. And the porosity and microstructure of part can be controlled by main sintered parameters. This research focused aliphatic Polycarbonate (PC) sintered with SLS. According to the orthogonal experiment, the effect of laser power energy and interaction between main sintered parameters on porosity has been studied. Then the micro structure and mechanical properties of specimens sintered with the best optimal parameters have been analyzed.

Abstract: Five-axis CNC machine tools are constituted by three-axis machine tools and two rotational degrees of freedom. Using the two rotary axes, five-axis CNC machine tools can improve the accessibility and become an important means of machining complex surface parts. In order to get high tapered complicated curved surface parts, a dual turntable five-axis machine with A-C tables was introduced and the mathematical models of the CNC processing of the workpiece were established. Through machining experiment of the several major processed forms, it shows that the dual turntable five-axis machine system has high machining quality and could be used to machine the difficult-to-cut materials, spatial complicated curved surface parts and special requirements.

Abstract: The Kovar alloy leads broke from two integrated circuits (ICs) with TO (Tin Outline) package. Through the metallurgical microstructure analysis, energy dispersive spectrometer (EDS) analysis and fractography analysis, the failure mode of the leads was found to be stress-corrosion-cracking. After checking the whole plating process, it was found that the residual chloride ions resulted in stress-corrosion-cracking. The chloride ions were absorbed inside the residual organic containment below Ni-plating layer. And a corrective measure was proposed.

Abstract: For the high-speed machining aero engine casing hole, according to the principle of metal forming and the characteristic of metal cutting plane strain, with selecting some key physical factors of the cutter - chip contact friction and abrasion model, the Cartesian orthogonal cutting model of aero engine casing hole was established by using the Deform, a sort of finite element analysis software. With taking cutting temperature for preferred aim of the cutting parameters, select the appropriate cutting parameters, the aim of aero-engine casing high-speed (cutting speed up to 700m/min) cutting has been achieved by simulation, and the feasibility of the cutting process was researched and confirmed in theoretically by analyzing the cutting force, cutting temperature and tool wear condition.