Vacuum Distillation And Preparation Of The 4n Fine Indium

Indium has lots of excellent physical-chemical property, and widely be used in the field of new and high technology. At present, the countries all over the world pay close attention to the development and application of indium. In resent years, the application in the plasma and LCD industry of transparent conductive electrode made of ITO is increasingly important. The research and development of alloy and semiconductor become future thrusts of indium. And those consumption is all taking high-pure indium as raw materials, so study the craft of purifying to the economic benefits improving indium industry, it is significant to promote the development of relevant industry of our country.Traditional precise indium prepares the craft to purify in advance - electrolysis , this law has certain deficiency , if production cycle is long, it is complicated to control the condition, chemistry is disastrous. As to this, this text puts forward the method to adopt vacuum distillation and prepares indium above 4N, and analyze from the theory , have basically got the process conditions which fetches 4N indium of making through the experiment.Firstly, the thermodynamics analysis is Carried through, according to different boiling point of various impurities and indium, the difference that the saturation vapor pressure of pure material the difference that separate coefficient β of indium-base-alloy , it is feasible to get rid of impurities in the indium, but the lead is relatively difficult to remove. Because raw materials content of tin is too high, two high-temperature distillation could receive qualified precise indium, on Olette equation Secondly analyze through dynamics , influencing the low boiling point impurity to separate from indium , the key link of the intensity is the diffusion in indium solution of impurity, it is the metal hot migration to influence the key link of the metal indium distillation.the low-temperature distillation study were carried out in an external-heat type vacuum furnace, the influence of distillation temperature, distillation time, the evaporated area and Material layer of thickness have investigated, we have got the suitable process conditions: distillation temperature is 1000℃, vacuum degree is about 15Pa, and distillation time is 270min. On this condition, it can remove cadmium from 0.0061% to 0.0001% , zinc is dropped to 0.0001% by 0.12%, thallium is dropped to 0.0007% by 0.178%, lead is dropped...