Abstract

It is established that 82% of the vapor can condense into the liquid phase when calcium is evaporated from an alloy with copper at low pressures of 0.7–1.33 kPa under nonequilibrium conditions. Based on values of the vapor pressure of calcium and copper determined using the boiling point approach, a complete diagram of state is constructed that includes the condensed and vapor phases at atmospheric pressure and in vacuums of 0.7 and 1.33 kPa. The temperatures of boiling and the composition of the condensate are calculated from the boundaries of the melt–vapor phase transitions. The condensate is represented by calcium with a copper content no greater than 3.95 × 10^–2 wt % and a boiling point 77–129°С higher than the melting point of Ca. It is assumed that the condensate remains in the molten state. The fundamental possibility of a liquid–vapor–liquid process that can be applied to distillation for the production of calcium is thus proved.

中文翻译：

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铜-钙系统中的液相-气相转变

摘要

可以确定的是，当钙在非平衡条件下以0.7–1.33 kPa的低压从铜合金中蒸发时，有82％的蒸气可以冷凝成液相。根据使用沸点法确定的钙和铜的蒸气压值，可以构建完整的状态图，其中包括大气压，真空度为0.7和1.33 kPa的冷凝相和蒸气相。沸腾温度和冷凝物的组成是根据熔体-蒸气相变的边界计算的。冷凝物由钙表示，铜含量不大于3.95×10 ^–2wt％，沸点比Ca的熔点高77–129°С。假定冷凝物保持熔融状态。因此证明了可以应用于蒸馏生产钙的液－气－液工艺的根本可能性。