Accomplished Something…

[4metals]

In fairness I've not had a Metastannic problem for twelve years

That is because you do 2 things which need to be highlighted.

One, you return it to the solution before de NOx
Two, you never return it to the solution after filtering and beginning your drop.

A problem some refiners have is they think if it’s OK to do it on a small scale, it’s OK to over do it as well. You surely are talking a drop of stannous per test. I have seen refiners dropping gold and pick up a squeeze bottle full of stannous and squirt it into the solution to see if they are done. Then they wonder why their gold isn’t pure!

Personally I’m a drop of solution and a drop of stannous on a strip of filter paper guy. A refinery always generates a collection of waste for burning and recovery and the test papers go that route.

 

[Yggdrasil]

Certainly does- the ancient analogy of "you don't lose your gold until you throw it away" springs to mind. I don't do this when dropping, I do it prior to denoxxing. After denoxxing I keep all the tests, and put them in my next dissolve so they stay in the mix.

In fairness I've not had a Metastannic problem for twelve years Ygg. Thinking a process through and removing the potential problem before it becomes an issue is the way forwards here.

I was guessing the Tin in the stannous did leave a minute amount, but should not pose an issue.

 

[anachronism]

That is because you do 2 things which need to be highlighted.

One, you return it to the solution before de NOx
Two, you never return it to the solution after filtering and beginning your drop.

A problem some refiners have is they think if it’s OK to do it on a small scale, it’s OK to over do it as well. You surely are talking a drop of stannous per test. I have seen refiners dropping gold and pick up a squeeze bottle full of stannous and squirt it into the solution to see if they are done. Then they wonder why their gold isn’t pure!

Personally I’m a drop of solution and a drop of stannous guy on a strip of filter paper guy. A refinery always generates a collection of waste for burning and recovery and the test papers go that route.

As per the bold - exactly. I've seen the squirt it in approach too, and honestly shake my head when I do. You're paper based I'm spoon based and I think that provided the mechanisms are understood, then both have their merits. It's when they are not understood that the issues occur which brings me back to the point that we don't have to be fully fledged chemists to do this but in order to be the best we can be, we have to understand the chemistry that underpins the reactions we are carrying out.

Only then can we deal with problems, or improve our processes. Knowledge is power.