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Up to now, separating Pb-Sb alloy obtained from jamesonite by conventional pyrometallurgy processes has many drawbacks such as long technological process, high energy consumption, and unsatisfactory separation efficiency. Thinking about the facts that antimony is used mainly in the form of Sb 2 O 3 , and separation of Sb 2 O 3 with good volatility from the lead melt is very easy under vacuum, vacuum dynamic oxidation process, a new and effective process for separating lead and antimony from Pb-Sb alloy, was developed in this work. Experimental results revealed that the content of antimony in Pb-Sb alloy decreased from 42% to 0.30%, that the removal percent of antimony reached 99.59%, and that the PbO content in the distillate was 0.12% under melt temperature of 953 K, vacuum treatment time of 210 min, and air flow rate of 3 L/min, corresponding to the system pressure of 14 kPa. This study is of significance for separating Pb-Sb alloy obtained from jamesonite. [ABSTRACT FROM AUTHOR]

Abstract: Separation and recovery process of zinc from scrap copper-based alloy was carried out under vacuum condition in a sublimation reactor. The factors affecting the evaporation ratio of copper-based alloy and the separation efficiency of zinc, such as heating temperature, residual gas pressure, vacuum evaporation time and the amount of scrap copper-based alloy were separately investigated. The experimental results revealed that zinc was successfully separated from the scrap copper-based alloy, where the evaporation ratio of copper-based alloy reached 18.43%. Namely, 96.09% by weight of zinc could be removed under the condition: residual gas pressure of 50 Pa, heating temperature of 1323 K and vacuum evaporation time of 90 min. If corresponding to the residual gas pressure 500 Pa, the evaporation ratio reached 18.17%, and 94.73% by weight of zinc could be removed under the following experimental conditions: temperature 1323 K, vacuum evaporation time 180 min. Meanwhile, the thermodynamics of vacuum sublimation and refining to recover zinc was analyzed and calculated. [Copyright &y& Elsevier]

Abstract: In crude lead or copper electrorefining, the by-product anode slime is an important material of recycling precious metals. However, the existing methods for treating arsenic-rich anode slime are less than satisfactory not only for the removal effect of arsenic but also for the environment protection. Therefore, a new technology for treating arsenic-rich anode slime was proposed in this paper, namely the two-step process of vacuum dynamic evaporation (VDE) and vacuum dynamic flash reduction (VDFR). Through this two-step process, silver from the anode slime was left behind in distilland as the silver alloy, and the trivalent oxide of arsenic was evaporated in the distillate. The experimental results showed that the removal ratio of arsenic was 99.96%. Moreover, these vacuum technologies offer improvements in metallurgical and environmental performance. [Copyright &y& Elsevier]

Conventional detinning process of lead bullion usually includes the following problems: the oxidizing refining process takes a long time to finish the oxidation of tin and products mass slag, while the basic refining process consumes large reagent, and the labor condition is poor. Therefore, a novel technique with oxygen controlled under vacuum condition for removing tin in crude lead was investigated, which shows characters such as, low-energy consumption, less metal wastage and environmental friendly. During this process, tin was removed from lead bullion by converting to tin oxide and concentrating in the dross. The experimental results showed that the residual Sn-concentration in detinned lead was about 2 ppm corresponding to the lead loss ratio about 2–3 wt% under the following experimental conditions: temperature of 750 °C, oxidation time of 80 min, agitation speed of 100 rpm and air flow rate of 60 mL/min corresponding to the residual gas pressure of 57 KPa. [ABSTRACT FROM AUTHOR]

A leak element has been developed based on anodic aluminum oxide (AAO) by means of the shadow coating technique. The gas flow through the leak element can exhibit the molecular flow in the pressure range from high vacuum to atmospheric pressure for helium and other heavy gases, since the AAO is made of multi tubes with the diameter of about 70 nm. The shadow coating technique could achieve a specific number of tubes on AAO to satisfy the conductance required for vacuum applications. Some key characteristics of molecular flow are demonstrated according to the conductance measurement using difference method. The flow rate of any other test gases introduced in to the vacuum chamber can be predictable with the known flow rate of helium through the fabricated leaks. [ABSTRACT FROM AUTHOR]

In this paper, we systematically investigate the morphological characteristics and evolution process of plasma induced pitting damage (PIPD) during the inductively coupled plasma (ICP) etching of fused silica with subsurface damage (SSD). Plasma induced pits are found to have uniform diameter as opposed to SSD induced pits. PIPD evolves differently in physical and reactive etching. In physical etching, the pit diameter increases linearly with etching time due to the etching of pit sidewall, while the depth remains constant. In CHF 3 plasma, depth also increases with etching time. This is due to the redistribution of F-based etchant caused by the pit sidewall, which enhances the local etching rate at the pit bottom. The fact that with increasing etching time the diameter increases linearly but remains uniform implies that all the pits are generated at the same time. More particularly, the fitted line suggests that PIPD forms at the beginning of plasma process. [ABSTRACT FROM AUTHOR]