Papers by Keyword: Melting Process

Abstract: Formation of crystal structures in glass ceramic is influenced by the heat treatment of parent glass. Most of research often studied on the important of sintering temperature and its soaking time. In this study, the effect of soaking time (3, 4 and 5 hours) during melting process (1550 °C) on crystal structures of Lithium Aluminosilicate (LAS) glass ceramic was conducted. All samples were then sintered at 900 °C for 30 minutes. The amorphous phase was identified prior to sintering process and transformed into crystalline phase for all samples after sintering process in XRD analysis. Major crystalline phase of high quartz solid solution and β-spodumene (LiAlSi₂O₆) were observed and higher intensity peak is found as the soaking time is longer. The microstructure of the sintered samples was observed under SEM and the particles were displayed an evidently growth of the grain as function to the soaking time. The functional groups of Si-O-Si and Si-O(Si, Al) bonding were appeared in fourier-transform infrared spectroscopy (FTIR) analysis corresponding to the silicates and aluminosilicate bonding. The results achieved present 5 hours soaking time during melting process was the optimum soaking time for melting LAS glass at 1550 °C.

Abstract: High alkali aluminosilicate glass batches were prepared by five different raw materials, reaction heat of which in melting process was studied by means of DSC thermal analysis method. The results show that reaction heat of batches in the heating process of 25-1600°C exists a significant difference, and which is among 4396.38 J/g-5311.14 J/g, moreover the least is the batches using petalite, while the most is spodumene. In the whole heating process, 380-800°C is carbonate decomposition stage, which accounts for 42-46% of the total absorbed heat; and 800-1200°C is silicate reaction stage, 40-50%; and 1200-1600°C is glass clarify and homogenization phase , 6%-16%. Therefore, carbonate decomposition and silicate reaction is the main part of batches heat consumption, the optimization scheme for materials has a significant effect on energy saving and emission reduction.

Abstract: Negative pressure is the main control variable in scrap copper smelting process, the control of negative pressure is not only closely related with producing safely, but also produces a direct impact on the quality of the anode plate, it is also a key breakthrough in energy saving. This paper first analyses the characteristics of negative pressure control in scrap copper smelting process, aims to larger overshoot and longer regulation under conventional PID control method, and then utilizes fuzzy control to correct the PID parameters online, to achieve the optimization control of negative pressure. Simulation result shows that the adjustment process of optimized control of negative pressure is steady and rapid, usually no or slightly overshoot, and the settling time is also reduced significantly.

Abstract: Ultra High Molecular Weight Polyethylene(UHMW-PE) pipe is a kind of pipe of thermoplastic engineering plastic with excellent comprehensive performance, but the difficulty in molding is a technical bottleneck which has already affected the extensive application of pipe of pure UHMW-PE. Molding in barrel on the Single screw extruder is a new technology of extrusion molding method, which can continuously carry out pipe of pure UHMW-PE, the most significant advantages of the technology are as follows: under the circumstances of no need to feed any additives in the whole forming process, it can continuously carry out pipe of pure UHMW-PE, and the extrusion molding speed of it is up to 12 m/h above. During the process of it based on molding in barrel technology, one of the main factors influencing to whether UHMW-PE pipe can be successfully molded or not is whether the melting process of raw material is adequate and appropriate or not. This article will elaborate melting characteristics of raw material of UHMW-PE, establishment of mathematical model of melting process, and numerical simulation of melting process, which belong to the forming process of molding in barrel, and will provide a theoretical basis for correctly designing the structure of single screw extruder and temperature control system of single-screw extruder, based on Molding in Barrel Technology.