Start with the system boundary
A recycling claim needs a starting point and an endpoint. A refinery may describe how much silver it recovers from material delivered to its process. A whole-system measure asks how much of the silver in discarded products eventually reaches the chosen recovered output. These percentages have different denominators. UNEP’s work on metal recycling treats collection, separation and final processing as connected stages; strong performance at the final stage cannot recover material that never arrives there.
Follow the contained silver
Consider a purely hypothetical batch of discarded products containing one kilogram of silver in total. This is contained silver mass, not one kilogram of mixed electronic waste. Suppose collection captures 50% of that silver, bringing 500 grams into the selected chain. Sorting then retains 80% of the collected silver in the stream sent for refining, leaving 400 grams. Each percentage applies to the silver entering that particular stage, not to the original product weight.
Multiply the stages
If the final refining stage recovers 90% of its incoming 400 grams, the chosen output contains 360 grams of silver. Overall recovery is therefore 0.50 × 0.80 × 0.90 = 0.36, or 36% of the original contained silver. The refinery’s 90% and the chain’s 36% can both be correct. Adding the three percentages or averaging them would answer neither question, because the later stages act only on material retained by earlier ones.
Ask where the rest went
In this simplified example, 500 grams are outside the collected stream, another 100 grams leave the selected route during sorting, and 40 grams do not reach the final recovered output. This does not mean those silver atoms were destroyed; their destinations would need separate accounting. Real systems include storage, reuse and additional treatment routes. Better collection and separation can therefore matter alongside refining performance. These invented yields explain the arithmetic and are not industry averages, facility results or estimates of global silver recycling.
Sources & further reading
- UNEP International Resource Panel — Metal Recycling: Opportunities, Limits, Infrastructure ↗
- UNEP — Metal Recycling: Opportunities, Limits, Infrastructure, summary ↗
- US Environmental Protection Agency — Electronics basic information, research and initiatives ↗
Sources checked 14 November 2026. Reference organisations do not endorse this website. Price examples are hypothetical and educational.