chemistry · tool
LSF / SM / AM Calculator
Compute the three control moduli (LSF, SM, AM) from an oxide analysis and flag them against typical ranges.
Executive summary
Enter CaO, SiO2, Al2O3, Fe2O3 (and optionally free lime) to get Lime Saturation Factor, Silica Modulus, and Alumina Modulus, each flagged low/in-range/high versus typical OPC references. The flags are advisory; plant targets are site-specific.
Calculator
| Modulus | Value | Typical range | Flag |
|---|---|---|---|
| LSF | 97.53 | 92–98 | in-range |
| SM | 2.62 | 2.3–2.7 | in-range |
| AM | 1.73 | 1.3–1.6 | high |
Typical ranges are general references, not targets. Plant targets are site-specific. Verify against your lab methods and standards before any quality or process decision.
Method
LSF = 100·CaO / (2.8·SiO2 + 1.18·Al2O3 + 0.65·Fe2O3); SM = SiO2 / (Al2O3 + Fe2O3); AM = Al2O3 / Fe2O3. Flags compare each value to typical OPC reference ranges (LSF 92–98, SM 2.3–2.7, AM 1.3–1.6).
Formulas (so an agent can compute without the UI)
LSF = (100 × CaO) / (2.8·SiO2 + 1.18·Al2O3 + 0.65·Fe2O3)
SM = SiO2 / (Al2O3 + Fe2O3)
AM = Al2O3 / Fe2O3
Typical OPC reference ranges (not targets): LSF 92–98, SM 2.3–2.7, AM 1.3–1.6.
Worked example
Inputs: CaO 66.6, SiO₂ 21.5, Al₂O₃ 5.2, Fe₂O₃ 3.0.
LSF = 6660 / (60.2 + 6.136 + 1.95) = 6660 / 68.286 ≈ 97.5 (in-range)
SM = 21.5 / (5.2 + 3.0) = 21.5 / 8.2 ≈ 2.62 (in-range)
AM = 5.2 / 3.0 ≈ 1.73 (high vs 1.3–1.6)
Copyable JSON input/output contract
{
"CaO": 66.6,
"SiO2": 21.5,
"Al2O3": 5.2,
"Fe2O3": 3
}{
"lsf": 97.53,
"sm": 2.62,
"am": 1.73,
"flags": {
"lsf": "in-range",
"sm": "in-range",
"am": "high"
},
"warnings": []
}Output values illustrate the contract shape; run the calculator for exact figures.
Inputs needed
| Input | Unit | Required | Notes |
|---|---|---|---|
| CaO | % | Yes | — |
| SiO2 | % | Yes | — |
| Al2O3 | % | Yes | — |
| Fe2O3 | % | Yes | — |
| freeLime | % | No | adds an LSF on combined CaO |
Outputs expected
| Output | Unit | Notes |
|---|---|---|
| LSF | — | with low/in-range/high flag |
| SM | — | with flag |
| AM | — | with flag |
| lsfCombined | — | LSF on (CaO − free lime), if free lime supplied |
Limitations & cautions
- Moduli summarize chemistry; they are not plant targets. Reference ranges are general, not targets — plant targets are site-specific.
- Oxide basis matters: mixing ignited and as-received analyses shifts every modulus. Keep a consistent basis.
- Garbage-in/garbage-out: results depend entirely on sampling quality and XRF calibration.
- Not a substitute for plant-specific QC review or for measured phase analysis (XRD).
- Verify against your plant's lab methods and standards before any quality or process decision.
⚠️ Safety & compliance
- Range flags are advisory. Do not change raw mix or kiln setpoints based on a flag without process engineering and QC review.
Authority: Raw mix and setpoint changes require process engineering and QC authority and your plant's standard procedure. This tool is advisory.
AI agent use cases
- Compute moduli from an oxide analysis and identify which is out of range and why.
- Replicate the calculation from the stated formulas when the UI cannot be run.
- Pre-screen a raw mix before proposing a proportioning change.
Human use cases
- Fast control-room or lab moduli check from routine oxides.
Related
Tools:bogue calculator
Prompts:raw mix correction
Pages:lsf sm am, raw mix design
Sources & assumptions
Assumption: Oxides entered on a consistent (ignited) basis unless stated.
Classical cement chemistry (Kühl / Bogue lineage) — modulus definitions