Advanced Materials Research Vols. 785-786

Abstract: In an open hematite pulp with Fe²⁺ or Fe³⁺, Mn²⁺ and Zn²⁺, the surface magnetization of mineral hematite was accomplished by mechanical stirring. The both systems of Fe²⁺ or Fe³⁺, Mn²⁺ and Zn²⁺ magnetized the hematite surface to improve the recovery of hematite by magnetic separation. In the presence of Fe²⁺, the recovery of hematite increased from 69.0% to 85.7% after magnetization when the pulp temperature was 65°C, the concentration of Fe²⁺ 1.8x10^-2mol/L, the concentration of OH^- 0.1mol/L, the stirring speed 400r/min and the reaction time 5min respectively, and the saturation magnetization of hematite also increased from 0.62emu/g to 1.07emu/g, while in the presence of Fe³⁺, Mn²⁺ and Zn²⁺ ions, the saturation magnetization increased to 0.79emu/g. So, the magnetization and the magnetic recovery of hematite in the case of Fe²⁺ is better than that of Fe³⁺, Mn²⁺ and Zn²⁺. The surface magnetization of hematite occurs due to the adsorption of ultra-fine particles with strong magnetism on the hematite surface in the form of aggregates in the case of Fe²⁺ while in the form of flakes in the case of Fe³⁺, Mn²⁺ and Zn²⁺.

Abstract: Rosin has been recognized as one of the most important renewable resources in the forest chemical industry. It is a complex mixture of acidic and neutral compounds. The isolation method, derivation and modification of rosin acids were summarized mainly, such as isomerization, disproportionation, hydrogenation, maleation and esterification of rosin acids were reviewed. It is considered that the derivation and modification of rosin acids is the most important way to use rosin in higher value.

Abstract: Sludge tends to accumulate easily in lake due to the closed water system and the pollutants contained inside could cause serious environmental problems. The sludge accumulation is mainly solved by dredging the lake, although the general disposal method of the dredged sludge by landfilling remains a problem due to formation of soft-ground and limited space. In this study, the conversion of the dredged sludge into adsorbent material that can be used for water treatment was tried. Using hydrothermal treatment in alkali medium, lake sludge which main components are silica and alumina could be converted into zeolite. The effects of various treatment conditions (NaOH concentration, alkali solution volume to dry sludge weight L/S ratio, Si/Al molar ratio, reaction temperature) were investigated. The adsorption abilities of synthesized zeolites were evaluated by measuring the cation exchange capacity (CEC) value and adsorption capacity towards heavy metals in aqueous solution (Pb, Cd). Soluble elements in sludge such as silica and alumina tend to dissolve at higher temperature and form zeolite. Zeolite type Na-P1 which was synthesized at silica/alumina (Si/Al) ratio of 2.5 and reaction temperature of 120°C showed the highest CEC value. The synthesized zeolites showed some adsorption ability towards heavy metals in aqueous solution (Pb²⁺ (Xm=55.3mg/g) and Cd²⁺ (Xm=40.9mg/g)).

Abstract: The study selects cylinder cloth which weaved by seamless fabric common materials as experimental samples, measures compressed thickness, bending length, extensibility, bending rigidity and etc index of fabrics, uses the stereotyped pleat recovery angle to characterize the setting effect. According to the experimental data, using statistical methods to analyze the correlation of these indicators and setting effects, ultimate goal is to improve fabric dimensional stability whatever wearing or stored, to provide a reference for optimizing the seamless fabric stereotypia. Results show that there is a close correlation between compression properties T2, T100, drape performance F0, shear stiffness G and stereotyped pleat recovery Angle.

Abstract: According to the process of anodic oxygen evolution in sulfate system for zinc electrolysis,Ti-base lead dioxide electrode can be prepared to use in this case.The surface characterization of the electrode was studied by Scanning electron microscopy(SEM) and X-ray diffraction(XRD).The electrode lifetime was tested in 1mol/L H₂SO₄ solution at 60°C,and the electro-catalytic properties was examined by polarization curves.Then these samples was enlarged and simulation test was conducted at Mengzi marriage zinc smelter in Yunnan.The results show that the electro-catalytic properties is better and the electrodes lifetime is longer compared to the traditional lead electrode.Moreover,it has a significant effect in reducing energy consumption, manufacturing cost and improving the production and grade of zinc.

Abstract: The decarbonized strips of high permeability grain-oriented silicon steel were annealed at different temperatures in a furnace after rolling at the ratio of 21.1%. The changes of the structure and the texture were analyzed by optic microscope and X-ray diffraction. Results show that the grains are easy to grow up and coarse after annealing, while the texture of the strips changes gradually from {111}<112> to {118}<110> and rotary cubic texture as the annealed temperature rises. The mechanism is that at a relatively lower cold rolling ratio, the distortion storage energy of the ferrite grains in the directions of {118}<110> and {100}<110> is higher than that of the {111}<112> grains so that the texture can form after a suitable annealing process.

Abstract: The separation process and the utility were considered simultaneously in order to reduce the cooling capacity of the propylene refrigeration system, and even to completely remove it. Two new types of heat pump distillation processes were proposed. The software Aspen Plus was used to simulate different heat pump distillation processes of ethylene and propylene to determine operating parameters and the best separation processes. The results show that the cold and hot utility would be reduced by 44.30% and 70.64% respectively when B-type and A-type heat pump distillation processes were used for ethylene and propylene separately. Furthermore, the temperature difference between hot and cold streams decreases after optimization by analyzing the T-H diagram. The energy has been more reasonably used, which proves the proposed processes are appropriate and effective.

Abstract: In recent years, microdrill becomes a very important element in the process of drilling apertures of PCB integrated circuits. But different material property will often generate collapse or fracture of the drill tip. This study is about to establish a finite element model (FEM) and to get the buckling stress analysis of the microdrill by ANSYS software. Since the microdrill is a structural brittle material and easy to be broken, force over buckling critical load is employed to explore the structural weakness and to analyze its stress damage. In addition, vibration, occurred at high-speed micro drilling, could easily lead to the excessive deflection or feeding amount of the drill tip, cause the collapse or rupture of the microdrill, and lower the quality by reaming the machining object. Poor geometric aspect ratio of the drill tip will generate different loads in different parts. How to manage the pressure for the microdrill to apply the force stably and to avoid the breakage and destruction is very important both for the tool life and the cost control. Therefore, how to overcome the buckling of tiny structure component under loading becomes a great issue to be explored.

Abstract: Hydraulic excavator plays a significant role in the modern engineering, it was bored complex and changing work stress and strain, its structural strength design directly affect the performance and reliability of the excavator. The virtual prototype technology can simulate all kinds of working conditions and achieve the ideal effect by optimizing parameters. In this paper, the 3D modeling of a hydraulic excavator was established using the Solidworks and converted into ADAMS software environment, added the constraints, the drives and loaded epigenetic reasonably and generated the main working parts of the virtual prototype model. The limit work trajectory displacement graph was given, and we obtained the change characteristic curve of the hinge point of the force at work. The static strength was analyzed by the finite element model in ANSYS, the stress and strain nephogram of the working device show that the reasonableness and correctness of the design, it provides a convenient and efficient means for the excavators design and optimization.

Abstract: Based on the viscoelastic material property of polyethylene pipe, software ANSYS was used to simulate and analyze the mechanical property of polyethylene pipe butt fusion joints with circumferential surface crack defects. The viscoelastic material creep parameters were characterized as Prony series and 1/4 node singular element was selected for meshing along the boundaries of the crack, then the stress intensity factor of polyethylene pipe butt fusion joints with circumferential surface crack was calculated under the uniform internal pressure. Through the finite element simulation, the result showed that polyethylene pipe were most likely to fracture failure when crack initiated. Thus the viscoelasticity of materials can be ignored when analyzing the stress intensity factor of circumferential surface cracks of polyethylene pipe. the main influencing factor of the circumferential crack defects was the ratio of the crack depth to the thickness of polyethylene pipe.