Industrial Method For The Chemical Removal Of Vanadium Impurities From Titanium Tubing

Vanadium impurities in titanium tubing are mainly VOCl3 and a small amount of discretionary VCI4, the presence of which gives a yellow color to TC4 titanium alloy tubing. The purpose of refining vanadium removal is not only for decolorization, but also for oxygen removal. This is an extremely important part of the refining process.
Titanium tubes and vanadium impurities ask discretionary boiling point difference and relative volatility are relatively small, such as titanium tubes - VOCl3 system of two components of the boiling point difference of 10 degrees Celsius, the relative volatility d = 1.22; and TC4 titanium alloy tubes - VCl4 system of two boiling point difference of 14 degrees Celsius. Nevertheless, theoretically speaking, the use of physical methods to remove vanadium impurities is possible, such as the use of high-efficiency distillation tower in addition to vanadium. The advantages of this method is no need to use chemical reagents, refining process foot continuous production, easy to realize automation, separated VOCl3 and VCl4 can be used directly. The disadvantage is that the energy consumption, equipment investment, but also need to solve the structure of high-power kettle, put has not yet been applied in industry.

In addition, TC4 titanium alloy tube - V0Cl3 system of two components of the solidification point difference is large, about 54 degrees Celsius difference, so can also be used in addition to the freezing crystallization method of VOCI3 but freezing consumes a lot of energy, so it has not yet gained industrial application. For this often used chemical method in addition to vanadium, chemical method in addition to vanadium is a chemical reagent added to the titanium tube, so that VOCl3 (or VCl4) impurities selective reduction or selective precipitation to generate insoluble alum compounds and TC4 titanium tubes separated from each other or selective adsorption of VoCl3 (or VCl4), so that the vanadium impurities and TC4 titanium tubes separated from each other; or selective dissolution of VOCl2, so that the alum impurities and 7ic alloy tubes. alum impurities and 7icld separate from each other. It can be said that a more ideal process equipment simple long low cost, good labor conditions, but also easy to realize the continuous operation of vanadium removal process has not yet been established. This is also the TC4 titanium alloy tube refining process needs to study the subject.