Cement Manufacturers Association (CMA)

46 Hypothesis Chemical additives can be developed to act as quality improvers and strength enhancers to offset poor quality of clinker produced from low grade / marginal grade limestones. UNISOL CHEMTECH Limited (UNISOL) has developed customized chemical additives, which when added at the cement grinding mill inlet in dosages ranging from 0.05% to 0.15%, help cement producers significantly reduce / eliminate their sweetener consumption. These chemical additives add value in one or more of the following ways: • Improved compressive strengths by 10-30% at various ages of strength development (example – 3-4 MPa @ 1D and 6-10 MPa @ 28D) • Modified PSD for desired quality • Modified setting time for meeting desired benchmarks • Improved grindability in cement mill These chemical additives can help cement producers reduce sweetener consumption, thereby reducing cost of cement manufacturing and enhancing sustainability of limestone deposits. “Sweetener” v/s Chemical Additives The table below provides a sample (representative) cost benefit estimate, while making certain assumptions. This is for a case where the cement plant reduces its sweetener consumption from originally 15% to an eventual 5%, by making use of a bespoke chemical additive acting as quality improver / strength enhancer. Table 2: Chemical Additives Replacing Sweetener – Sample Cost Benefit Analysis Add: Cost of Chemical Additive • Tentative blended cost of chemical additive formulation: Rs 80k per ton • Typical dosage: 0.05% of cement mill feed • Treatment cost: Rs 40 per ton of cement Net Savings (Rs 79 – Rs 40) = Rs 39 per Ton of Cement Subtract: Reduced Sweetener Cost • Differential between Sweetener and marginal-grade limestone: Rs 750 per ton • Reduction in sweetener content by addition of chemical additives: 10% • Conversion factor (Limestone to Clinker): 67% • Average clinker factor in cement: 70% • Cost reduction due to lower sweetener content: Rs 79 per ton of cement The above calculations only consider direct and tangible gains on variable cost. The intangible, indirect and long-term gains include: • Lower carbon footprint: Clinker produced from lower grade limestone causes lower CO 2 emissions. Carbon taxes are being imposed in certain parts of the world already, but even otherwise there is a moral need to reduce CO 2 emissions.