I've run a few batches so far using the method of cementing silver out of solution using copper. I used stranded copper speaker wire due to its high purity and high surface area. The higher surface area speeds up the process. I guess the cementing process is exothermic because I noticed that the solution heated up at least during one of the batches and maintained an elevated temperature.
I observed that when I cemented at a slower rate, the end product is much lighter in color and almost white. When i tried rushing, the solution became very warm, bubbles would even form, and the end product looks more gray. In my last batch, I added copper at an extremely fast rate, and the cemented product started turning dark gray at one point (no longer silver I would guess) and a lot of bubbles formed at the copper-solution interface. When I opened the flask, orange-brown gas (NO2 i would guess) formed. I cooled the solution down, stirred, and it became a bit lighter, but still nothing close to the first batch where I added copper slowly.
So I have three different products ranging in color from white to a light grey, but all are different shades. I would assume the color has some dependence on purity, is this true?
All in all, I am wondering if cementing at lower temperatures is beneficial in increasing silver purity? I know it slows down the process, but if pure silver is what you want, it may be worthwhile.
I observed that when I cemented at a slower rate, the end product is much lighter in color and almost white. When i tried rushing, the solution became very warm, bubbles would even form, and the end product looks more gray. In my last batch, I added copper at an extremely fast rate, and the cemented product started turning dark gray at one point (no longer silver I would guess) and a lot of bubbles formed at the copper-solution interface. When I opened the flask, orange-brown gas (NO2 i would guess) formed. I cooled the solution down, stirred, and it became a bit lighter, but still nothing close to the first batch where I added copper slowly.
So I have three different products ranging in color from white to a light grey, but all are different shades. I would assume the color has some dependence on purity, is this true?
All in all, I am wondering if cementing at lower temperatures is beneficial in increasing silver purity? I know it slows down the process, but if pure silver is what you want, it may be worthwhile.