Screening mass-balance calculator
Calculate on-size recovery, off-size contamination and reject load while checking total and size-class closure.
Entries stay in this browser page and are not submitted to IOP. Export CSV or print / save as PDF before leaving. These worksheets organise project evidence; the responsible team defines and approves the requirements.
Equations and interpretation
| Metric | Equation | Boundary |
|---|---|---|
| Total closure residual | 100 × (combined outlet rate − feed rate) / feed rate | Signed residual; the selected tolerance applies to its absolute value. |
| On-size recovery | 100 × accepted on-size / feed on-size | A recovery measure; not accepted-product purity. |
| Undersize removal | 100 × undersize in undersize reject / feed undersize | Material reporting to the designated undersize outlet. |
| Accepted contamination | 100 × (accepted undersize + accepted oversize) / accepted total | Reports both off-size classes together. |
| Reject / total screen feed | 100 × (both reject-stream totals) / screen feed total | Not recycle / fresh feed; those use different denominators. |
| Size-class residual | 100 × (outlet class total − inlet class rate) / total feed | Uses total feed as denominator so a zero inlet class remains interpretable. |
The balance assumes a steady measurement interval, no unmeasured stream and no net inventory change. The class comparison additionally assumes no creation or destruction of the defined size classes. Breakage, agglomeration or inconsistent sampling can violate that assumption. Zero denominators produce “Unavailable”; total closure outside the selected tolerance withholds performance ratios. A recovered class exceeding its inlet flow withholds recovery/removal ratios. Other class imbalances remain visible warnings and must be resolved before acceptance.