Process, quality, and energy optimizationPQ-007

Lower clinker LSF while preserving strength

Golden Bay Cement Company · Portland cement plant, New Zealand · historical trials; updated 2025

Use this record when

The decision this case can inform

Use this record when testing whether clinker chemistry can be relaxed without sacrificing finished-cement strength or compliance.

Evidence scope

GCP supplier case based on laboratory and plant trials. Strength and LSF results are reported, but net energy, CO₂, durability, and cost outcomes are not quantified.

Source-supported facts

What the public record actually establishes

4 sourced points
  1. F1

    The reported raw mix was approximately 75% cement rock and 25% high-grade limestone, with a silica ratio near 4:1.

  2. F2

    The program used laboratory screening followed by plant trials of a cement quality improver.

  3. F3

    Supplier-reported mortar strength increased from 58 to 65 MPa and reference concrete from 28–30 to 32–34 MPa.

  4. F4

    Clinker LSF was reduced from 98 to 95 while the plant reportedly maintained cement strength.

Structured interpretation

Facts and reported results are kept separate from the lesson a plant may choose to test.

01

Operating context

High LSF and a high-silica raw mix supported strength but increased fuel demand.

02

Intervention or finding

Laboratory and plant trials evaluated a cement quality improver at lower clinker LSF.

03

Documented result

Supplier reports mortar strength 58 to 65 MPa, reference concrete 28-30 to 32-34 MPa, and clinker LSF reduced from 98 to 95 while maintaining cement strength.

04

Plant interpretation

Optimize clinker chemistry and finished-cement performance together using controlled trials, standards, durability review, and surveillance.

05

Transfer boundary

Supplier-reported; energy, CO2, and cost reductions are not quantified.

Before applying the lesson

Questions to verify at your plant

These are decision checks, not operating instructions. Resolve them through local risk assessment, technical review, and authorization.

  1. 01

    Are trials designed around local raw materials, cement standards, sulfate balance, fineness, additives, and customer applications?

  2. 02

    Do strength results extend across ages, production variability, and durability requirements rather than one endpoint?

  3. 03

    Are kiln stability, free lime, refractory conditions, cement performance, and additive dose tracked together?

  4. 04

    Will verified fuel, power, clinker factor, CO₂, and total cost determine whether the change creates net value?