Premium Sodium Metabisulfite (SMB)
The Professional Choice for High-Purity Gold Precipitation
Unlock professional-grade results in your jewelry studio with our high-potency Sodium Metabisulfite. Specifically sourced for the selective precipitation of gold from Aqua Regia solutions, this technical-grade reducer is an essential staple for jewelers, refiners, and hobbyists looking to reclaim precious metals with laboratory-standard precision.
Why Use Our SMB?
- High Selectivity: Drops gold effectively while keeping base metals and PGMs in solution.
- Rapid Recovery: Quickly reduces to heavy metallic gold particles.
- Clean Precipitation: Produces a distinct "gold mud" that is easy to filter and wash.
| Available Sizes | Recommended Application |
|---|---|
| 2 lb | Hobbyists and small-batch bench scrap recovery. |
| 5 lb | Regular studio use and medium-scale projects. |
| 10 lb | Professional jewelry shops and commercial refining. |
| 50 lb | High-volume industrial use and maximum cost-efficiency. |
Refining Guide: The "Selective Drop" Method
Sodium Metabisulfite reacts with water and gold chloride to yield pure metallic gold
1Denitration
Ensure your Aqua Regia solution is free of residual Nitric Acid. Use Urea or evaporate the solution to a syrupy consistency. If "free" nitric remains, the precipitated gold will immediately re-dissolve.
2Preparation
Mix a saturated solution by dissolving 1 oz of SMB into 4 oz of boiling distilled water. Stir until clear. Note: This will release a pungent sulfur odor. Ensure proper safety and ventilation with use
3The Precipitation
Slowly add the SMB solution to your filtered gold chloride. The liquid will shift from bright yellow/green to a dark, opaque brown as the gold "drops" out of suspension.
4Testing and Recovery
Allow the gold to settle for at least 30 minutes. Use a Stannous Chloride test on the remaining liquid to confirm all gold has been recovered. If the test is negative, siphon the waste and wash your gold powder with boiling distilled water.
⚠️ Critical Safety Information
Sulfur Dioxide Gas : Contact with acid releases toxic gas. ALWAYS work in a professional fume hood or outdoors. Wear an acid-gas respirator, chemical-resistant gloves, and eye protection. Never mix in unventilated spaces.
Note: Precious metal refining involves hazardous chemicals. Ensure you are familiar with local disposal regulations and safety protocols.