1、Ammonium tungstate method Tungsten concentrate is alkalized by sodium hydroxide, neutralized with hydrochloric acid, and then acted with ammonium chloride to generate ammonium tungstate, and then add hydrochloric acid to carry out the acid decomposition reaction to generate tungstic acid, and then decomposed and crushed by roasting to get tungsten trioxide.
2、Hydrochloric acid decomposition method of tungstate. Sodium tungstate Na2WO4, calcium tungstate CaWO4 and other tungstate saturated aqueous solution is heated, according to the molar ratio of the solution is slowly added to the 2 ~ 3 times the excess of boiling concentrated hydrochloric acid. Yellow tungstic acid is precipitated according to the above reaction. At this point, if the rate of titration is too fast or the liquid temperature drops, it is easy to produce a suspended or colloidal precipitate, which makes the next step difficult. After dropping and heating continuously on the water bath for 1h, the precipitate becomes easy to filter. After standing, it was washed several times with 5% ammonium nitrate aqueous solution to remove Cl- completely. After filtration, it was dried at 120℃, and then tungstic acid was completely dehydrated into tungsten trioxide after heating up to 600℃.
3、Thermal decomposition of ammonium paratungstate. Will be purified by recrystallization method of ammonium paratungstate (NH4)10W12O41-11H2O loaded into the porcelain crucible, heated to about 400 ℃ above, ammonia volatilization out of the tungsten trioxide.
More details of tungsten oxide product, please visit website: tungsten-oxide.com
Please contact CHINATUNGSTEN for inquiry and order of tungsten oxide:
Email: sales@chinatungsten.com
Tel.: 86 592 5129595
