Maximise clinker substitution with supplementary cementitious materials
SCM solutions and know-how to optimise clinker substitution
Many cement producers today use supplementary cementitious materials (SCMs) as a partial substitute for clinker in their production processes. In addition to reducing the clinker factor, SCMs contribute to the strength properties of cement through hydraulic or pozzolanic activity.
With the right approach, SCMs offer important advantages, including lower cement production costs and CO2 emissions as well as a concrete end-product with lower permeability and greater strength.
Supplementary cementitious materials can be added either individually or in different combinations with clinker to create a blended cement. In a cement plant, SCMs can be adopted in the burning or grinding processes, depending on the SCM, local requirements and the intended quality. SCMs can also be added to the cement at the ready-mix plant when making concrete.
Pozzolan or hydraulic activity
The most common types of SCMs are fly ash, slag, silica fume, calcined clay, and natural pozzolans.
Pozzolans are particularly attractive to cement producers. Natural pozzolans are clay-like minerals with hydraulic properties that can be extracted directly from the ground. However, pozzolans in their natural form are only present in certain regions of the world. When not available, a viable alternative is to calcine normal clay at high temperature. This activates the pozzolan so that it develops hydraulic properties similar to natural pozzolans.
However, not all clays have the same potential to develop hydraulic properties through calcination. Achieving the right result with calcined clay requires the appropriate knowledge, experience and technology, as well as a thorough understanding of the chemistry of your raw materials and the clay sources.
Maximising clinker substitution through chemistryFLSmidth can help you achieve the cement properties suitable for your market. We provide advanced laboratory testing services to help you evaluate whether a material is an appropriate SCM and what is needed to achieve the desired cement quality.
Our testing procedures include:
- Sample preparation
- Chemical and mineralogical characterisation
- Physical testing
- Activation utilising the calciner process
- Colour control of product
- Grinding and physical testing
- Compressive strength testing
Equipment designed for SCMs
With our assistance, you can maximise the use of SCMs in your cement production. We help with material evaluation, process design and supply of specialised equipment, such as our unique clay calciner system. We design the optimal process and provide the equipment to achieve your goals.
Our clay calciner system can accept various types of materials and fuels, while giving you fine control over the activation process to achieve the highest quality product.