Geo said:The solution isn't really needed to dissolve the gold. The chlorine gas will dissolve the gold without the need for the gold to be submerged in solution. Use a 4 or 6 inch piece of schedule 40 PVC pipe about three foot long. Fit the pipe with a cap on one end and a threaded clean-out on the other end. Break the material up in pieces to fill the pipe. Add 200ml's HCL. Add 50ml's house hold bleach and screw in the plug. The pipe and fittings are rated for 480 psi. It will pressurize the tube. Shake the tube up and down, back and forth a few times and leave it closed for a few hours safely away from people and pets in a secure area with the screw cap up. After a few hours time, slowly and safely unscrew the cap (always wear eye protection and other PPE's) and let the pressure off the tube. For a few cents and a little time more, add a PVC ball valve in the cap to let off the pressure. Gently rinse the material with a spray bottle of water until all the material is rinsed. The gold should be gone from the material and in solution.
You will need to check the rating on the pipe for this to make sure it is rated for pressure. not all SCH 40 pipe is pressure rated. It would be better to use grey SCH 80 pipe for this procedure IMHO.