There are many impurities in the coarse Gr5 titanium alloy tube. After classification, in order to facilitate analysis, a representative impurity is found in each group of impurities as a key component to represent the main separation limit of the 4B system. It shows that in the crude Gr5 titanium alloy tube liquid when a key component is qualified in refining, it can be considered that all impurities in this group have been basically separated and removed. The selected key components should not only have large content but also be difficult to separate. Find out FeCl3 in high boiling point impurities, SiCl4 in low boiling point impurities, and VoCl3 in impurities with similar boiling points as key components of this group. In this way, the separation of a multicomponent system can be simply regarded as the separation of a SiCl4-TiCl4-VOCl3-FeCl3 quaternary system.
Different separation methods should be used to refine various impurities in coarse Gr5 titanium alloy tubes due to their different characteristics.
The impurities with high boiling points and low boiling points in the crude Gr5 titanium alloy tube liquid can be separated by physical method distillation or distillation according to their characteristics of the large difference in boiling point or relative volatility from the Gr5 titanium alloy tube liquid.
The solubility of solid impurities with high brushing points such as FeCl3 in the 6Al4V titanium alloy tube is very small, and some of them are dispersed in the Gr5 titanium alloy tube as suspended solids. In the chlorination process, most of the suspended solids have been removed by mechanical filtration. However, the remaining very fine solid impurity particles form a glue solution in tetrachloride and dissolve a small amount in the Gr5 titanium alloy tube, which can not be completely removed by mechanical filtration alone. Distillation is required for refining.
The distillation method must be carried out in the distillation tower. The bottom temperature of the distillation tower is slightly higher than the brushing point of the Gr5 titanium alloy tube (about 140-145 ℃), and the volatile component Gr5 titanium alloy tube is partially gasified; FeCl3, a non-volatile component, remains at the bottom of the tower due to its low volatility. Even a small amount of volatilization may be condensed by the falling condensate and fall back to the tower width. The tower top temperature is controlled to be at the boiling point of the Gr5 titanium alloy tube (about 140 ℃). As there is a small temperature gradient in the tower, the steam of the Gr5 titanium alloy tube forms an internal cycle in the tower. The upward steam contacts the falling droplets, which conducts a heat and mass transfer process and increases the separation effect. In this process, impurities at high-temperature points such as FeCl3 in the steam of Gr5 titanium alloy tube rising along the tower gradually reduce. Pure Gr5 titanium alloy tube steam is selected from the tower top and condensed into distillate through the condenser, while FeCl3 and impurities at constant high whisk points in the kettle practice liquid are continuously enriched and regularly discharged to separate them.
