What is the primary purpose of IS 12089?

To define the quality requirements for granulated slag to be used in the manufacture of Portland Slag Cement (PSC).

What is the minimum required glass content in the slag?

The minimum glass content must be 85 percent by mass (Clause 6).

What is the maximum permissible sulphide sulphur content?

The maximum sulphide sulphur (S) content is 2.0 percent by mass (Table 1).

How is the chemical composition of slag verified?

As per the methods specified in IS 4032: Methods of chemical analysis of hydraulic cement (Clause 4.2).

IS 12089

: 1987

Specification for granulated slag for the manufacture of Portland slag cement

CurrentSpecializedSpecificationMaterials Science · Cement, Concrete, Aggregates and RCC

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This standard specifies the chemical and physical requirements for granulated blast furnace slag, which is a key ingredient for manufacturing Portland Slag Cement (PSC). It ensures the quality, consistency, and suitability of the slag for producing durable and strong cement.

Specification for granulated slag for the manufacture of Portland slag cement

Quick Reference Values

Minimum Glass Content85% by mass

Maximum Sulphide Sulphur (S)2.0% by mass

Maximum Manganic Oxide (Mn2O3)5.5% by mass

Maximum Magnesium Oxide (MgO)17.0% by mass

Minimum Hydraulic Index (CaO+MgO+1/3Al2O3)/(SiO2+2/3Al2O3)1.0

Maximum Insoluble Residue5.0% by mass

Maximum Fineness (Blaine)450 m²/kg

Key Formulas

Hydraulic Index = (CaO + MgO + 1/3 Al2O3) / (SiO2 + 2/3 Al2O3)

Practical Notes

The glass content is the most critical parameter as it directly relates to the hydraulic (cementitious) activity of the slag.

This standard is primarily used by cement manufacturers and quality control labs, not typically by site engineers for design or construction.

Ensuring low moisture content and freedom from foreign materials as per Clause 3 is crucial for smooth plant operations and consistent cement quality.