Manufacturing cement has always been a complex, highly technical process requiring tight control of each production step. Now, sustainability is bringing additional challenges, as manufacturers aim for lower energy consumption and greenhouse gas (GHG) emissions, and conservation of natural resources. Many industry players have committed to reducing their CO2 emissions by 30% by 2030 compared with 1990 and are expecting to achieve lifetime neutrality for concrete by 2050.
Achieving these goals requires continuous adjustments across the whole value chain, from raw materials to final product. Several new solutions to reduce CO2 emissions in cement production are now being explored – in particular, cutting clinker emissions and creating ‘green’ cements. In addition to supporting sustainability and circularity targets, these approaches can also deliver cost reductions.
Reducing manufacturing emissions
Process efficiency, energy consumption, emissions, and final product quality are all affected by the elemental and mineralogical composition and fineness of the raw materials, the intermediates and additives added, and the quality of any alternative fuels. As such, high-quality material characterisation is more important than ever in making these new solutions successful.
Aerial view of cement factory tower
Over 85% of the cement industry’s emissions are generated during clinker production. Improved production efficiency, digitalisation, alternative fuels, and renewable energy (often with a kiln upgrade) can help reduce these. But 60% of emissions within that 85% come from chemical reactions when heating limestone. This makes lowering the clinker factor the most effective solution. Thanks to a lower standard deviation on key parameters of the cement manufacturing process (such as LSF), the clinker content of a cement can be accurately monitored, and therefore decreased, with optimised final properties of the cement.
Improving kiln efficiency
Optimising operating conditions in the raw milling and pyro-processing stages can play a big role in maximising efficiency. First, to ensure that raw mix particles can be easily combined without hard burning, it is key to make sure these particles are fine enough.
Close up of flame in rotary kiln during heating mode in cement plant
The stable chemical composition of raw meal can also help enable strong properties in the clinker by ensuring consistent heat profiles in the kiln. To achieve this, manufacturers can adjust the raw meal’s chemical composition in real time using a cross-belt analyser (neutrons on/off). The CNA Pentos from Malvern Panalytical is a specialised elemental analyser, which uses the pulsed fast and thermal neutron activation (PFTNA) technology in an on/off configuration for a well-controlled use, easy maintenance and utmost safety.
Next-generation analysis
Fig. 1- Lime saturation factor adjustment using traditional lab compared to CNA
On-line analysis removes any transport and processing delay, allowing for immediate correction of mix proportioning ratios whenever necessary. To avoid the need for sampling, PFTNA analysis measures the material on a belt from top to bottom and side to side to provide rich and representative data. The CNA Pentos takes measurements every minute, eliminating delays and downtime, which results in a consistently stable kiln feed.
This high-frequency control replaces expensive sampling equipment and laboratory costs, and the CNA Pentos enables higher throughputs, reduced energy consumption, and effective use of replacement materials. In turn, this reduces both cost and CO2 emissions.
The consistent and reliable data provided can help reduce production costs, optimise fuels and power costs, and help manufacturers to comply with the required quality of cement. Controlling production through on-line analysis with real-time data also helps eliminate human error and minimise non-conformities.
Specifically, on-line solutions such as the CNA Pentos address the common issue of sampling representativity, which is one of the most critical parts of the monitoring and control process.
Malvern Panalytical CNA Pentos
How to move forward
Developing a CO2 -neutral cement and concrete sector is certainly a daunting challenge – but the industry is bringing a wide range of innovative solutions to this task.
At Malvern Panalytical, we are proud to be part of the solution to the net-zero cement challenge by helping our customers adapt their processes and ingredients successfully. The CNA Pentos is just one part of our plan to achieve this goal; to learn more about how we are shaping the sustainable cement and concrete of the future, visit our website.
Read our full article on increasing efficiency, lowering costs, and moving toward a greener cement industry here.
Written by Malvern Panalytical.
