How is gold refined?

1. First crush the gold ore. 2. Put into a large pool containing a water solution of sodium cyanide, so that the gold dissolved in sodium cyanide. （3. Collect the sodium cyanide solution and put it into the metal silver (or copper) for the replacement reaction. 4. After the reaction of the silver embryo into the Petri dish bowl in high temperature melting, in addition to the silver and copper residue on the surface of the melted material, you get crude gold. To get more pure gold, further refining is required.