Sep 15, 2018
The preparation process of pure metals can be summarized into two types.
First, the metal compounds are precipitated, solvent extraction, ion exchange and other pure metal compounds, and then reduced to pure metal. Pure titanium, such as pure titanium, is usually purified by TiCl4 distillation and then reduced to pure sponge titanium.
The two is to get coarse metal and then purify it into pure metal. There are two kinds of purification methods: chemical purification and physical purification.
Chemical purification methods include electrolytic refining, oxidation refining, chlorination refining, disproportionation metallurgy and so on.
Physical purification methods include regional purification, distillation, rectification refining, drawing single crystal, vacuum refining and so on.
Pull-out crystals are the methods by which single crystals are pulled from the melt by seed crystals or in-situ seed crystals to purify metals. The physical purification method is simple, easy to operate and less contaminated by reagents. It can be used as a final purification method. Chemical purification method has great flexibility and strong selectivity, but it often has the disadvantage of reagent contamination. It is widely used in pre-purification and intermediate purification. But in production, the two methods are often used together. At present, ultrahigh purity germanium with 12 "9" purity can be prepared, and seven "9" or more high purity silicon, arsenic, gallium, indium and so on can be prepared. These high purity metals are used as semiconductor industrial materials.