Making cement manufacturing more efficient

From concrete production to general contracting, there is a growing focus around the world about the need to reduce our carbon footprint. The increased awareness of CO2 emissions from cement production has brought focus on techniques that improve sustainability.

Grinding aids and quality improvers can reduce emissions

Two ways to reduce your carbon footprint is through grinding aids and quality improvers. Grinding aids reduce the energy needed for cement grinding, lowering costs and carbon emissions. This allows a 5% output increase (or 5% power savings) equal to between 1 and 3.5 kwn/ton of cement. Quality improvers increase strength, allowing the introduction of supplementary cementitious materials in place of clinker, reducing both costs and emissions. 

Improved sustainability in cement plants

GCP helped a Tunesian cement plant use an OPTEVA™ CBA® quality improver to lower production costs, increase mill throughput, and reduce greenhouse gas emissions. The OPTEVA™ CBA® product enabled the plant to improve production by 20 tons per hour, or 17%. The plant reduced clinker factor by increasing limestone by 5%. The cement maintained comparable strength with lower production costs. With these measures, and production of one million tons of cement per year, the plant achieved 4,000 tons of CO2 reduction from electricity savings and an additional 45,000 tons of CO2 reduction from clinker replacement. 

    Grinding Aid only OPTEVA™ CBA® 
Dosage kg/t 0.15 0.315
Mill output Tph 120 140
BSA m2/kg 317 308
Fineness, 90 mm % 9.5 8.5
SO3 % 2.1 2.1
Limestone % 11.9 17.0
Set time, initial Min 150 160
Set time, final Min 240 245
Strength, 2 day MPa 17.1 17.4
Strength, 28 day MPa 48.0 48.3

Another example is a cement plant operating in Algeria that produces more than five million tons of cement per year. The plant introduced GCP’s OPTEVA™ XS 255 quality improver, enabling an increase in limestone content from 6% to 15%, with a corresponding drop in clinker factor by 9%. This lowered production costs, and also reduced CO2 emissions by 365,000 tons per year. At the same time, both the strength and fineness of the cement increased, resulting in improved cement quality. 

CO2 reduction could have been even greater, had the plant used increased grinding efficiency with OPTEVA™ XS 255 for improved throughput rather than increased fineness.

    Untreated OPTEVA™ XS 255
Dosage kg/t   1.2
BSA m2/kg 340 388
Fineness, 90 mm % 4.2 2.8
CaCO3 % 6.1 15.2
Target limestone % 5 15
Air % 5.6 5.8
Strength, 2 day MPa 23.0 27.3
Strength, 28 day MPa 48.8 56.8
Normalized strength, 2 day* MPa 23.0 25.8
Normalized strength, 28 day* MPa 48.8 55.3

*Normalized fineness parameters of untreated cement 

Discover more ways to improve sustainability. 

 

Tags
  • Building Envelope Solutions
  • CBA
  • Cement production
  • Concrete
  • Grinding aids
  • OPTEVA™
  • Structural Solutions
  • Sustainability