I tried to refine gold, and I had something very strange happen. I have a bar of mixed metals made up of gold plated material. There is copper mixed in it for sure, and I would assume other metals too like steel, aluminum, and solder.

I put this bar in muriatic acid mixed with $\ce{H2O2}$, the reaction is over and by now it is just muriatic acid again, just more diluted.

Then I put the bar in a solution of baking soda mixed with water with acid still on it and an acid/base reaction happened. What I don't get is that within seconds the gold on the surface of the bar went into solution.

What happened, how the gold was dissolved, and how do I get it out of the solution?

  • 2
    $\begingroup$ You put a gold-plated bar in a mixture of $\ce{HCl}$ and $\ce{H2O2}$ (what mixture and molarity?) to achieve what result? And then you put the bar, presumably still gold-plated(?), in an aqueous solution of $\ce{NaHCO3}$ and observed what reaction? And you determined the gold was dissolved how? $\endgroup$ – feetwet Sep 4 '17 at 21:59