I have been having trouble with stannous chloride testing solution for several years now. As a result, almost all of my recovery and refining work has been blind. My workspace for metals recovery and refining is outside in an unheated and open to the elements building (very positive air flow). As with the OP of this thread, I am wondering about heat / cold and the efficacy of stannous chloride testing solution in cold (below freezing) temps. Most nights fall well below freezing so keeping it from freezing is not going to be very easy, especially if that is when I am working the metals.
To make it, I use user '4 metals's recipe of: 2 grams stannous chloride crystals, 1 gram tin electrode metal, 40 ml distilled water, 10 drops of HCL
However, it will only work ever so weakly if I heat the tested drops (on paper towel) over a heat source that nearly burns the paper towel. Otherwise the solution under test drops and testing solution drops all become clear until much later and everything has evaporated dry.
What the bleep am I doing wrong? I have tried 3 different reagent grade containers of stannous crystals, Do the crystals themselves go bad in the container? I did find a loose lid on the main container I was using but that shouldn't kill all the other reagent grade stannous in other containers.
The testing solution I would make used to work when I first started in the metals work 6 or 7 years ago, but now every time I make a solution, it is like I am using something that is deliberately masking any reaction.
Something in the paper towels?
Any one else ever seen this behavior? Thanks in advance for your consideration.