stannous test flip-flop

[octane0]

I have just finished processing a small batch of CPU's (all ceramic) in AR and all seemed to go well. I filtered my gold bearing solution into a clean beaker with a bit of ice to chill it. I tested my solution as I was doing this and got a very clearly purple positive. Once it was chilled I dropped in 8 ml of Sulphuric to help aid in dropping out some of the metals I'm not interested in and did indeed get a fair amount of light grey pricipitate(settled to the bottom) and a cloudy substance suspended in the solution that once concentrated in a filter was very similar to butter. At this point my liquid had changed color a bit to a lime green and when I tested with stannous again it's negative, no darkening of any shade in fact the green stain caused by the solution being dropped onto filter paper is cleared up when stannous is applied. At this point I added a couple of grams of Sodium Carbonate to try and bring the PH up a bit and got it up to between 1-2 added SMB and got nothing, no reaction, no precipitate, color changed a little to sort of resemble tea with a slight green tint and it has a strong vinegary odor.Sorry about being so long winded but I thought it best to get all the details out there because usually the mistake is in the details. If any one can suggest anything I would be very grateful. Thanks

 

[nickvc]

Welcome to the forum.
I am assuming your first test was done on the original solution before you decided to filter it, I'm asking because of you left that solution with the scrap still in for any time and not all the base metals had dissolved your gold could well have cemented back onto the scrap, try adding a small amount of AR to the left over scrap and see if you get any reaction, if so that's where your gold is.