This is for Determination of Cluster Index Direct – Reduction Iron Ore Pallets as per ISO 11256, The test sample is isothermally reduced in a fixed bed at 850ᵒC under static bed load using a reduction gas consisting of H₂ , CO, CO₂ and N₂ managed through SCADA-PLC based digital automatic control panel, until 95% of reduction is obtained. The reduction test portion (Cluster) is disaggregated by shattering, using special Shatter Index attachment as per ISO 11256. The Clustering Index is calculated as the mass of clustered material accumulated after specified disaggregation operations.

            Core Principles of the ISO 11256 Test

The laboratory method quantifies how easily pellets form fused agglomerates under static load and gas reduction.

• Isothermal Reduction: A test sample of iron ore pellets is heated and maintained in a fixed-bed reaction vessel at a constant temperature of 850 °C.
• Static Load: A defined, continuous mechanical load is applied vertically on top of the pellet bed to simulate the downward physical pressure inside a shaft furnace.
• Gas Composition: A reducing gas mix consisting of Hydrogen (H₂), Carbon Monoxide (CO), Carbon Dioxide (CO₂), and Nitrogen (N₂) passes through the bed.
• Target Reduction: The gas flow continues until a 95% degree of reduction is achieved across the test sample.
• Disaggregation: The resulting fused mass (the cluster) is subjected to mechanical stress via a standard shattering or tumbling operation to break apart loosely bound materials.
• Calculation: The Clustering Index (CI) is calculated as the final mass percentage of remaining clustered aggregate material after the standardized tumbling/shattering steps.