The preparation of tungsten wire from tungstic acid may be went through states changing of tungstic acid→tungsten trioxide→tungsten powder (doped tungsten powder)→tungsten wire, the specific processes are like follow:
1. From tungstic acid to tungsten trioxide (WO3), it will need to go through calcination process which the tungstic acid is often heated to 100°C for removing molecule of complex water to convert to yellow WO3, wherein the equipment maybe baking furnace (Quartz Tube Electric Furnace);
2. From tungsten trioxide to tungsten powder (doped tungsten powder), it is supposed to a process of hydrogen reduction (Or carbon reduction which is now rarely used, because tungsten and carbon is easily combined to generate WC powder) to get tungsten powder, wherein the reducing furnace may be taken on; furthermore, if the product has something special requirement (such as tungsten filament), then other element (Like the tungsten filament needs dope oxides of potassium, silicon and aluminum) to get doping tungsten powder;
3. From tungsten powder (doped tungsten powder) to tungsten wire, there are processes of pre-treatment, steel forming or cold isostatic pressing forming and drawing by all kinds of drawing die of tungsten powder, and hydraulic or cold isostatic press, drawing die maybe used. Wherein, forming is an important process of powder metallurgy, the process of metal tungsten powder to go for briquetting with a certain shape, size, porosity and strength.