Can tungsten that oxidizes trap gold?

[CalDreamer]

I didn't expect a positive stannous cloride test.

I put it in H202 to see if I could put the Tungsten completely in solution and remove it from the refining equation. In the comments above a member said that H202 would attack the Tungsten, and I figured it would not attack the gold without something else in the mix (such as CuCl). I thought I was trying W + 3H2O2 = WO3 + 3H2O. However, with the plated Au and a yellow precipitate plated on the chip after AR, I just want to check the solution.

I thought the clear solution would just be excess H2O2 and H2O. I just have a habit of testing every solution with Stannous Cloride. I expected no reaction. If the reaction is just showing that the clear solution had Tungsten in it, then great. In that case, maybe I leave it in the test tube until the Tungsten plate is gone or maybe I increase the 35% H2O2.

I was worried the cemented gold may have a different reaction to H2O2 than metallic gold, so I thought I would ask members.

 

[Lino1406]

The grey material is SnO2. SnCl2 + H2O2 = SnO2 + 2HCl

 

[CalDreamer]

Thanks.

After the chips went through AR, and then heated HCL and water baths, I didn't think there would be any tin left for the H2O2 to attack.

 

[anachronism]

Thanks.

After the chips went through AR, and then heated HCL and water baths, I didn't think there would be any tin left for the H2O2 to attack.

aha! That's clearer. If I had read your post properly I wouldn't have asked what I did. My bad.

So your ceramic had residual HCL on it, and you added peroxide to it. Yes that could give a positive stannous test in some circumstances.

 

[CalDreamer]

Thx anachronism.