Naga
09-09-2011, 10:45 PM
I have an alloy that I thought might have been contaminated with zinc. I discovered some muriatic acid in the basement, so I decided to try the muriatic acid test on a bit of the alloy. I put some in a glass cup, spilling a bit on the concrete floor in the process. It immediately began to fizz and bubble and turn yellow upon contact with the concrete, so I know it is working. I dropped a bullet cast from the aforementioned alloy in the cup, and watched it for a few minutes, and nothing happened. I went away and came back about 20 minutes later, and discovered a fine stream of small bubbles rising from the bullet to the surface of the acid. The bubbles burst and didn't form any sort of froth on the surface. I poured out the acid and checked the bullet, and aside from a bit of darkening in color, it was unchanged. There was no green foam present, as I have read will happen when muriatic acid comes into contact with zinc. Was the acid reacting to something else in the alloy, or is zinc present?