How particle sizing boosts cement quality without costing the earth
Cement manufacturers are under increasing pressure to cut costs while reducing the impact that their CO2 emissions have on the environment. A major target for these reductions is the cement milling stage.
Controlling cement properties through precise milling
The milling stage of cement production has a significant impact on the final qualities of the mixture because it is a strong determinant of the mixture’s particle size distribution. It is also energy intensive.
Strict control is therefore required to conserve energy while also guaranteeing the following key parameters:
- Hydration rate and strength: Finer particles have a larger surface area, which speeds up the hydration process and leads to faster strength development.
- Quality control: Consistent particle size distribution ensures uniform quality of the cement. This is important for maintaining the desired properties of the final product, such as workability, setting time, and durability.
- Energy efficiency: Monitoring and controlling particle size during the grinding process can help optimize energy consumption. Overgrinding can lead to excessive energy use, while undergrinding can result in poor product quality.
- Cost management: By ensuring the correct particle size distribution, manufacturers can reduce waste and improve the efficiency of the production process, ultimately lowering costs.
- Performance characteristics: Different applications may require cement with specific particle size distributions to achieve desired performance characteristics, such as high early strength or low heat of hydration.
Every cement mixture contains a range of particle sizes, and every particle size contributes differently to that mixture’s qualities at different stages of production. So what’s the optimal particle size distribution for cement?
In cement, every particle size matters
Every fraction of the particle size distribution plays a role in determining cement performance.
Particles that are too fine (<2 μm diameter) lead to the cement curing exothermically, setting too fast and cracking. Large particles (>32 μm) may not fully hydrate during routine use, reducing the strength of the final product. Typically, optimum strength is achieved if 50-70% of the product lies between 2 and 32 μm, depending on the intended grade of the final product.
Understanding the particle size distribution of your cement mixture helps you fine-tune its properties at different stages of production and avoid over- or undermilling and the associated energy costs. You just need the right methods. Here’s how Malvern Panalytical’s particle size analysis instruments deliver these insights.
Get deeper insight into your cement mixture with laser diffraction tools
Some traditional methods for particle size distribution, such as Blaine measurements, give you just one number representing particle size. This single number tells you nothing about the size of your largest particles or the breadth of the size distribution – two important factors for your analysis! This means that two cement mixtures with very different hydraulic properties could share the same Blaine number, causing irregularities in processing.
To avoid this type of irregularity occurring, you need deeper insight into particle size distribution, fast. Malvern Panalytical’s laser diffraction instruments offer you a way to these insights. Laser diffraction is a non-destructive method that measures particle size distributions by passing a laser beam through a particulate sample and measuring the angle of the scattered light. Our easy-to-use software then generates usable insights almost immediately, helping you fine-tune your mixture to suit your ideal process parameters.
Here is a selection of the instruments on offer:
Insitec / Labsizer
- Insitec uses laser diffraction technology to deliver on-line continuous particle size analysis for process monitoring. Its insights help you achieve the correct properties in your cement grinding while saving electricity.
- Want an example of the benefits? One US cement producer used Insitec to boost its feed rate by 15% while cutting the amount of energy needed to mill each ton of cement by over 20%. The cost of investment in Insitec and the corresponding software package paid for itself in energy savings alone.
- The Mastersizer is the world’s most popular particle sizing instrument. Fast, reliable, and easy to use, the Mastersizer can be incorporated into lab testing with minimal training required, thanks to software that guides users through every stage of the measurement process.
- Particle size isn’t the only factor that affects cement’s surface area and therefore its reactivity: particle shape is also important, mainly for research. The Morphologi 4-ID is a static image analysis instrument that gives you insight into particle shape and cross-validates particle size measurements from laser diffraction.
- Automated image analysis doesn’t require manual operation and can therefore be integrated seamlessly into automated quality control procedures.
To learn more about Malvern Panalytical’s suite of analytical instruments for building materials applications, please visit our building materials webpage or download our analytical toolbox brochure.
Plus, stay tuned for our next blog on Sample preparation for XRF and ICP.
Further reading: