Refining Silver with a Sulfamic Acid System
Six months ago, I started learning and experimenting with silver refining using a sulfamic acid system because nitric acid is difficult to obtain where I live.
My setup per cell:
- 50–70 g sulfamic acid
- 1.5 L DI water
- 20 g MSG additive
- Stainless steel cathodes submerged, with approximately 8 × 8 cm of surface area per cathode face
- Mixed silver feedstock (95%, 92.5%, and 83.0%) cast into anodes
- Low current density (~0.5 A range)
This is my first time doing any of this, so there have been plenty of mistakes and learning experiences along the way: furnace issues, contamination, poor melts, forgetting to remove base-metal pieces, chemistry mistakes, silver melting problems, filtration challenges, and of course a few spills.
From the first 500 g batch of material, I've recovered roughly 300 g so far (~60% recovery) and still have approximately 160–180 g of material remaining in process as feedstock, silver-bearing powders, slimes, filters, and solutions. The full lot consists of approximately 7 kg of sterling silver and another 3 kg of 800/830 silver.
I've been tracking every run, so I started building my own Android app specifically for this refining process.
Current features
- Cell management
- Harvest logging
- Bleed/populate event tracking
- Photo capture
- Voice notes
- Inventory management
- Waste-stream tracking
- QR labels
- Knowledge library containing information from a separate subsystem, including data extracted from US Patent 3616332
- Local Ollama AI integration
Instrumentation and monitoring
- DPS-series programmable power supply telemetry
- pH monitoring
- TDS/DI water quality measurements
- Temperature logging
- Current and voltage tracking
- Mass-balance and yield tracking
- Photo-based run documentation
I'm also working toward a low-cost silver composition/purity analyzer to help estimate electrolyte condition, contamination levels, and feedstock composition without relying on expensive commercial equipment.
The project has evolved from "How do I refine silver?" into "How do I build a measurable, repeatable, and data-driven refining process?"
The long-term goal is to build a closed-loop refining system that combines process logging, instrumentation, inventory management, waste tracking, analytical tools, and knowledge management. The objective is to understand where every gram goes, reduce losses, improve recovery rates, and continuously refine the process through measurement and data collection rather than guesswork, so I rely less on memory and maintain a proper record of runs, changes, observations, and yields.
It's still very much a work in progress, but it's already helping me manage multiple cells, runs, and experiments while building a better understanding of the chemistry and process behavior.
Photos attached show various snapshots from the past six months, including cell development, harvested crystals, anodes, instrumentation, and the software ecosystem being built around the refining process.
I'm curious whether anyone else here has experimented with sulfamic systems and what crystal morphology you're seeing compared to nitrate-based electrolytes.