Identify the numerator and denominator
NETL's University of Kentucky pilot report discusses mixed rare-earth oxide purity within a specific test programme. A purity result describes the product tested; it does not by itself establish how much of the feed's rare earths reached that product.
For recovery, define the target element or group, the incoming amount and the measured output boundary. For purity, identify the product and the analytical basis. A high-purity mixed rare-earth product also differs from a high-purity individually separated oxide.
NETL: University of Kentucky pilot-scale rare-earth extraction ↗
Keep stage and overall recovery distinct
A leach-stage result can be followed by losses during purification, separation or finishing. If the question concerns saleable output, assess the whole route rather than quoting the best-performing stage. Do not multiply percentages unless their bases and sequential boundaries are compatible.
For supplier comparison, attach conditions and scale to both measures. A selected laboratory sample, pilot campaign and operating average can each be valid observations but are not equivalent evidence of recurring performance. Ask which result represents the intended commercial feed and required product specification.
A worked hypothetical example
A feed contains 100 kilograms of a target material and the defined output contains 80 kilograms of it: recovery to that boundary is 80%. If the output weighs 100 kilograms in total, its target-material purity is also 80%, but for a different reason. Further purification could raise purity while losing some target material, so one measure may improve while the other declines.
Read processing percentages correctly
| Measure | What it tells you |
|---|---|
| Recovery | Target material retained across a defined step |
| Purity | Target material fraction within a product |
| Overall recovery | Retention through the full specified route |
Your review checklist
- Define the target material.
- Record each percentage’s denominator.
- Distinguish mixed and separated products.
- Retain test scale and process boundary.
Investigate with Oreline
Use Oreline’s evidence view to inspect the product and scope behind processing claims. Keeping those findings connected to the project helps your team compare technical progress without confusing impressive percentages with equivalent commercial output.
Follow the evidence through the supply chain.
Explore Oreline’s guided investigations. No account required.
Explore the sandbox →Frequently asked questions
Can a product be very pure but have low recovery?
Yes. Purifying a small recovered fraction can produce a high-purity sample without recovering most of the target material.
Does high recovery guarantee saleable product?
No. The product must also meet the relevant specification and acceptance requirements.