Material Recycle Index calculator.
Quantify the fraction of all process materials that are recovered and recycled. MRI captures the circular economy performance of an entire process — across reagents, solvents, catalysts, and auxiliaries — in a single percentage. Results update live as you type, and every session stays in your browser, never on a server.
What is the Material Recycle Index — and why does it matter?
The Material Recycle Index (MRI) measures the fraction of all materials used in a chemical process that are successfully recovered and recycled, expressed as a percentage. Unlike the E-factor, which quantifies waste generated, or the Solvent Recycle Index (SRI), which is limited to solvents, MRI provides a holistic, process-wide view of circular material use — capturing reagents, solvents, catalysts, auxiliaries, and workup materials together.
A high MRI reflects a genuinely circular process: materials are not simply used once and discarded, but are recovered, returned to the process, and their embedded energy and cost are preserved. This aligns directly with Green Chemistry Principle 1 (Prevent Waste) and supports the broader goals of industrial circular economy.
The formula
| Symbol | Term | Units |
|---|---|---|
| $\text{MRI}$ | Material Recycle Index | % (0–100%); ideal = 100% |
| $m_{\text{recycled}}$ | Total mass of all materials successfully recovered and recycled back into the process or supply chain | g (or kg) |
| $m_{\text{total input}}$ | Total mass of all materials entering the process (reagents, solvents, catalysts, auxiliaries, workup materials) | g (or kg) |
"Recycled" means material that is recovered and returned to use — either back into the same process step, to another step, or to an external supply chain. Material sent to incineration, landfill, or waste water treatment is not recycled. The denominator is the total mass of all materials input to the process, not just the waste. A higher MRI is always better.
MRI benchmarks by context
| Process type | Typical MRI | Notes |
|---|---|---|
| Highly optimised industrial process | 60–90% | Closed-loop solvent recovery, catalyst regeneration |
| Pharmaceutical API synthesis | 10–40% | Complex workup, limited solvent recovery, single-use reagents |
| Undergraduate teaching lab | 0–15% | Minimal recovery; solvents typically disposed |
| Ideal circular process | 100% | All auxiliary materials recovered; only feedstock atoms consumed |
Strengths and limitations
Strengths
- Captures circular economy performance across the entire material inventory
- Simple to calculate from lab records; no molecular weights needed
- Complements E-factor: high MRI directly reduces E-factor waste total
- Comparable across processes and scales; useful for benchmarking improvements
- Highlights which material categories have the greatest recovery potential
Limitations
- Treats all materials equally: 1 g of water = 1 g of expensive chiral catalyst
- Does not capture the quality or purity of recovered material
- High MRI for water recovery may mask poor performance for high-impact solvents
- Does not capture energy consumption, toxicity, or lifecycle impacts
- Requires experimental data — cannot be calculated at the design stage
MRI in context: complementary green metrics
| Metric | What it measures | Ideal direction |
|---|---|---|
| E-Factor | Mass of all waste per mass of product | Minimise (→ 0) |
| PMI | Total material input per mass of product | Minimise (→ 1) |
| SRI | Fraction of solvents recovered and recycled (%) | Maximise (→ 100%) |
| MRI | Fraction of all materials recovered and recycled (%) | Maximise (→ 100%) |
| WRR | Fraction of generated waste that is recovered/recycled | Maximise (→ 100%) |
Experiment details
Process materials
Enter all materials used in the process: reagents, solvents, catalysts, and workup/purification materials. For each entry, enter the total mass used and the mass successfully recovered and recycled. The desired product(s) should not be included here — MRI measures the recycling performance of auxiliary and process materials, not product recovery.
| Material name | Category | Mass used (g) | Mass recycled (g) | Recycle % |
|---|
Results
Recycled vs. not recycled by category
Recycled vs. not recycled mass balance
Detailed breakdown & interpretation
| Material | Category | Mass used (g) | Recycled (g) | Not recycled (g) | Recycle % | Visual |
|---|---|---|---|---|---|---|
| Enter materials above to see breakdown. | ||||||
Interpretation
Save & load sessions
Sessions are stored in your browser only. No data leaves your device.
Export
Export your MRI calculation as a PDF report or CSV data file. PDF opens in a new tab and uses your browser's print function. CSV downloads directly.
Where can I read more?
References are sorted alphabetically by first author.
- P. T. Anastas and J. C. Warner, Green Chemistry: Theory and Practice, Oxford University Press, 1998. ISBN 978-0-19-850698-0. — Original statement of the 12 Principles; frames waste prevention as Principle 1.
- C. Jiménez-González et al., Org. Process Res. Dev., 2011, 15, 912–917. DOI. — Introduces PMI; discusses material efficiency and solvent recycling in pharmaceutical processes.
- G. A. Keoleian and I. S. Jawahir, in Treatise on Sustainability Science and Engineering, ed. J. K. Jawahir, Springer, 2013. — Circular economy metrics for chemical processes including material recycle rates.
- R. A. Sheldon, Green Chem., 2007, 9, 1273–1283. DOI. — E-factor and complementary green metrics including material recovery.
- R. A. Sheldon, Green Chem., 2023, 25, 1704–1728. DOI. — Updated green metrics landscape including material recycling and circular chemistry.
Contributors
Roles follow the CRediT taxonomy (Contributor Roles Taxonomy), adapted for educational software. Hover a contributor's name for a summary, or a column header for the definition of that role.
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© 2025– DodecaGreen Project. All rights reserved. · Last updated: 08/06/2026
This portal was built with the assistance of a large language model (Claude, Anthropic), which was used to generate and refine code, articulate and structure contributed ideas within the defined page format, and support iterative design decisions. All scientific content, conceptual frameworks, pedagogical choices, and final outputs were directed, reviewed, and verified by the contributors listed above.
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