The neutral zinc sulfate solution obtained from hydrometallurgical process of Angouran zinc concentrate has cadmium, nickel and cobalt impurities, that must be purified before electrowinning. Therefore, cadmium and ni...The neutral zinc sulfate solution obtained from hydrometallurgical process of Angouran zinc concentrate has cadmium, nickel and cobalt impurities, that must be purified before electrowinning. Therefore, cadmium and nickel are usually cemented out by addition of zinc dust and remained nickel and cobalt cemented out at second stage with zinc powder and arsenic trioxide. In this research, a new approach is described for determination of effective parameters and optimization of zinc electrolyte hot purification process using statistical design of experiments. The Taguchi method based on orthogonal array design（OAD） has been used to arrange the experimental runs. The experimental conditions involved in the work are as follows： the temperature range of 70-90 ℃ for reaction temperature（T）, 30-90 min for reaction time（t）, 2-4 g/L for zinc powder mass concentration（M）, one to five series for zinc dust particle size distributions（S1-S5）, and 0.1-0.5 g/L（C） for arsenic trioxide mass concentration. Optimum conditions for hot purification obtained in this work are T4（85 ℃）, t4=75 min, M4=3.5 g/L, S4（Serie 4）, and C2=0.2 g/L.展开更多
This study aims to examine the usability of environmentally harmless vegetable oil in the minimum quantity of lubrication(MQL)system in face milling of AISI O2 steel and to optimize the cutting parameters by different...This study aims to examine the usability of environmentally harmless vegetable oil in the minimum quantity of lubrication(MQL)system in face milling of AISI O2 steel and to optimize the cutting parameters by different statistical methods.Vegetable oil was preferred as cutting fluid,and Taguchi method was used in the preparation of the test pattern.After testing with the prepared test pattern,cutting performance in all parameters has been improved according to dry conditions thanks to the MQL system.The highest tool life was obtained by using cutting parameters of 7.5 m cutting length,100 m/min cutting speed,100 mL/h MQL flow rate and 0.1 mm/tooth feed rate.Optimum cutting parameters were determined according to the Taguchi analysis,and the obtained parameters were confirmed with the verification tests.In addition,the optimum test parameter was determined by applying the gray relational analysis method.After using ANOVA analysis according to the measured surface roughness and cutting force values,the most effective cutting parameter was observed to be the feed rate.In addition,the models for surface roughness and cutting force values were obtained with precisions of 99.63%and 99.68%,respectively.Effective wear mechanisms were found to be abrasion and adhesion.展开更多
碳化硅(SiC)因其优异的物理化学特性被广泛应用于高端光学元件制造,但其高硬脆性和化学惰性导致加工过程存在效率低、易损伤等问题。本研究提出一种基于磁流变弹性体工具的化学机械抛光方法,通过有效融合材料表层氧化反应与机械去除行...碳化硅(SiC)因其优异的物理化学特性被广泛应用于高端光学元件制造,但其高硬脆性和化学惰性导致加工过程存在效率低、易损伤等问题。本研究提出一种基于磁流变弹性体工具的化学机械抛光方法,通过有效融合材料表层氧化反应与机械去除行为实现SiC的高效抛光。本研究结合单颗磨粒去除行为分析模型与芬顿催化反应原理,设计四因素三水平正交实验,探究抛光工具Fe_(3)O_(4)磁性颗粒质量分数、抛光液H_(2)O_(2)浓度、抛光速度及外部磁场强度等对Si C材料去除率和表面粗糙度的影响规律。通过理论分析与实验研究发现,抛光速度对材料去除率的影响最为显著(48.35%),而抛光液H_(2)O_(2)浓度对表面粗糙度的影响占主导作用(51.15%),在Fe_(3)O_(4)质量分数6 wt%、H2 O 2浓度9 wt%、抛光速度40 r/s及磁场强度300 m T的优化工艺参数实验条件下,SiC试件表面粗糙度由初始的1.688μm降至0.267μm,材料去除率可达3.842μg/h,揭示了氧化层生成速率与机械去除效率协同作用对磁流变弹性体工具抛光过程的影响规律,为复杂曲面SiC光学元件的可控柔性抛光提供了理论依据与工艺参考。展开更多
文摘The neutral zinc sulfate solution obtained from hydrometallurgical process of Angouran zinc concentrate has cadmium, nickel and cobalt impurities, that must be purified before electrowinning. Therefore, cadmium and nickel are usually cemented out by addition of zinc dust and remained nickel and cobalt cemented out at second stage with zinc powder and arsenic trioxide. In this research, a new approach is described for determination of effective parameters and optimization of zinc electrolyte hot purification process using statistical design of experiments. The Taguchi method based on orthogonal array design（OAD） has been used to arrange the experimental runs. The experimental conditions involved in the work are as follows： the temperature range of 70-90 ℃ for reaction temperature（T）, 30-90 min for reaction time（t）, 2-4 g/L for zinc powder mass concentration（M）, one to five series for zinc dust particle size distributions（S1-S5）, and 0.1-0.5 g/L（C） for arsenic trioxide mass concentration. Optimum conditions for hot purification obtained in this work are T4（85 ℃）, t4=75 min, M4=3.5 g/L, S4（Serie 4）, and C2=0.2 g/L.
文摘This study aims to examine the usability of environmentally harmless vegetable oil in the minimum quantity of lubrication(MQL)system in face milling of AISI O2 steel and to optimize the cutting parameters by different statistical methods.Vegetable oil was preferred as cutting fluid,and Taguchi method was used in the preparation of the test pattern.After testing with the prepared test pattern,cutting performance in all parameters has been improved according to dry conditions thanks to the MQL system.The highest tool life was obtained by using cutting parameters of 7.5 m cutting length,100 m/min cutting speed,100 mL/h MQL flow rate and 0.1 mm/tooth feed rate.Optimum cutting parameters were determined according to the Taguchi analysis,and the obtained parameters were confirmed with the verification tests.In addition,the optimum test parameter was determined by applying the gray relational analysis method.After using ANOVA analysis according to the measured surface roughness and cutting force values,the most effective cutting parameter was observed to be the feed rate.In addition,the models for surface roughness and cutting force values were obtained with precisions of 99.63%and 99.68%,respectively.Effective wear mechanisms were found to be abrasion and adhesion.
文摘碳化硅(SiC)因其优异的物理化学特性被广泛应用于高端光学元件制造,但其高硬脆性和化学惰性导致加工过程存在效率低、易损伤等问题。本研究提出一种基于磁流变弹性体工具的化学机械抛光方法,通过有效融合材料表层氧化反应与机械去除行为实现SiC的高效抛光。本研究结合单颗磨粒去除行为分析模型与芬顿催化反应原理,设计四因素三水平正交实验,探究抛光工具Fe_(3)O_(4)磁性颗粒质量分数、抛光液H_(2)O_(2)浓度、抛光速度及外部磁场强度等对Si C材料去除率和表面粗糙度的影响规律。通过理论分析与实验研究发现,抛光速度对材料去除率的影响最为显著(48.35%),而抛光液H_(2)O_(2)浓度对表面粗糙度的影响占主导作用(51.15%),在Fe_(3)O_(4)质量分数6 wt%、H2 O 2浓度9 wt%、抛光速度40 r/s及磁场强度300 m T的优化工艺参数实验条件下,SiC试件表面粗糙度由初始的1.688μm降至0.267μm,材料去除率可达3.842μg/h,揭示了氧化层生成速率与机械去除效率协同作用对磁流变弹性体工具抛光过程的影响规律,为复杂曲面SiC光学元件的可控柔性抛光提供了理论依据与工艺参考。
