If you're trying to recover gold without aqua regia

 

One effective method is using **sodium metabisulfite** (SMB), which is a popular and cost-effective precipitant for gold recovery. It can precipitate gold from a solution where gold has been dissolved by an alternative method, like using hydrochloric acid and a suitable oxidizer, such as hydrogen peroxide, or chlorine bleach (sodium hypochlorite).

### Recovery Steps with Sodium Metabisulfite (SMB)

1. **Dissolution**: First, dissolve the gold using hydrochloric acid and an oxidizer like hydrogen peroxide or chlorine bleach, forming a solution of gold chloride.

   

2. **Neutralization**: Make sure the pH of the solution is not too acidic (usually around pH 1-2 is ideal).

3. **Precipitation**: Add SMB gradually to the solution. SMB will reduce the gold ions to metallic gold, which will settle as a fine brown powder.

4. **Filtration and Rinsing**: Once the gold has settled, filter the solution, rinse the gold powder, and dry it. 

5. **Melting**: The powder can then be melted down to form pure gold.

### Alternative Recovery Methods with Ferrous Sulfate

Ferrous sulfate is another precipitating agent for gold:

1. **Add Ferrous Sulfate**: Once your gold is in a chloride solution, add ferrous sulfate. This will also cause gold to precipitate out as fine brown powder.

  

2. **Filter and Process**: Filter and rinse the powder thoroughly before drying and melting.

Both SMB and ferrous sulfate are effective, but **SMB tends to be preferred due to its simplicity and faster reaction** time in precipitating gold. However, **make sure to handle all chemicals with proper safety protocols** as both methods involve potentially hazardous materials.