Tungsten Trioxide Testing Method
Thiocyanate colorimetry :
The method is applied in testing the samples WO3 containing the concentration of 0.2~65% or little valence manganese.
The needed reagents:
1. Sodium dioxide:Na2O2
2. Sodium hydrate,5%
3. Potassium thiocyanate,50%
4. Stannous chloride,5%
5. Titanium trichloride,5%
6. Hydrazine sulfate
7. Sodium hypophosphite, solid
The preparation method of WO3 standard solution as follow:
1. Put 0.1000g tungsten trioxide into 300ml breaker, then add 50g NaOH, 200ml water, and move into 1000ml volumetric flask after dissolved, finally shake up and get WO3 0.1mg，100ug.
2. Use 5% NaOH accurately dilute 10times and get 10µg tungsten trioxide per ml.
3. Burn tungsten trioxide one hour under the temperature of 800℃.
Method description:
Use Na2O2 as a sample and put into the water. The hydrochloric acid is used as the medium to reduce the stannous chloride and titanium trichloride to pentavalent. Then use thiocyante to generate green –yellow tungsten acyl thiocyanate complexes. Finally, make test based on the product.
Specific procedure:
First, put 0.2~1.00g NaOH in the iron pot and add Na2O2，then use the glass rod to stir.
Second, heat the sample in the temperature of 750℃ until the sample melts into red fluid and take out cooling about five minutes, then put the product into 250 ~ 300ml wide mouth jar and cover the surface.
Third, stir the solution when the bottom of the jar turn into precipitation and put into 100ml volumetric flask and shake.
Finally, place the clarified or dried solution 2~10ml on the 25ml colorimetric tube or 50ml volumetric flask. Add 10ml 5% NaOH, sodium hydroxide, hydrazine sulfate and a small amount of 50% sodium hypophosphite and shake immediately. Then dilute 5%SnCl2 solution to nearly scale, and add 5%TiCl3 solution 1 drop with a solution of 5%SnCl2 rushed to scale, and shake. Finally, place it about 15minutes and test the absorbance value when the wavelength reaches 405 ~ 420nm (real 430nm).
More details of the above news and/or products, please visit Chinatungsten Online, or contact us directly.
Disclaimer: The article is only reflecting the opinions of the author. We have no responsibility to prove the originality and authenticity of the content, words and/or pictures. You readers should just take it as reference and check the details by yourselves. And the content is not a suggestion for investment decision. The investor takes his or her own risks if he or she operates accordingly. If you have any dissent about the contents above, please contact the relevant author, or the webmaster. We will try our best to assist the dealing of the related issues. Thanks for your visit and cooperation.
|
