Batch to batch consistency with on-line QC

At Ash Grove Cement's Leamington plant in Utah, cement fineness is traditionally measured off-line using an air permeability technique ("Blaine") and is correlated to the compressive strength of the cement at 1,3, 7 and 28 days after setting.

Taking a year's worth of QC data, the variability in certain cement product parameters was compared for off-line and on-line techniques. These parameters included:

• % fines (%<30µm)
• Blaine fineness
• compressive strengths at 1, 3, 7 and 28 days after setting

In the graph below we can see that the variability in the cement fineness and strength has decreased significantly since the installation of Malvern Insitec and the commissioning of automatic separator control.