Is that possible to extract gold after dissolving by using aqua regia??
There are several ways:
If the solution contains Platinum or Rhodium impurities, these can be first precipitated with Ammonium Chloride and patience.
Next you add Sodium Metabisulfite to precipitate the gold. This precipitate is gold powder. Filter it off, rinse repeatedly with water to remove trace acid, then dry it. The product is a red-orange powder that looks nothing like what you'd expect.
The final step is to melt the gold powder into its more traditional form. This can be done, small scale, in a small lab crucible with a MAPP torch. Take care in this process as the expanding gas from the torch head will "blow away" your gold. The process of vacuuming up the gold, incinerating your vacuum filter, dissolving the trace gold with AR again, and re-precipitating sounds fun as a technical challenge.