How do you make cement eco-friendly? Automated on-line analysis is part of the answer

Manufacturers in the cement industry have been looking to reduce their environmental impact. Recent innovations in green cement are one result of these efforts. Attention has also been paid to the cement-making process itself, with goals to improve the uniformity of input materials, reduce energy consumption and CO₂ emissions, and increase productivity. A key tool in achieving these improvements is the CNA Pentos Online Analyzer (OLA). How does this cutting-edge analysis instrument help improve raw material uniformity?

What is cement raw material uniformity?

When you’re baking and you use several packs of flour from the same brand, you can safely assume their quality is similar between packs, if not identical. But this isn’t so for cement raw materials. The chemical composition of materials from the same deposit – be it limestones, clay, mudstone, or shale deposits – can vary greatly. This issue is further compounded when materials are sourced from different suppliers and energy coming from various alternative fuels.

Improving the uniformity of key intermediary products of cement (raw materials, raw mix, alternative raw materials) involves screening different batches of the same material to provide the right constant mix with the same composition, which is especially important when using Alternative Raw Materials (ARMs)  for the raw mix or Supplementary Cementitious Materials (SCMs) to be added to the clinker. If there isn’t uniformity – and this is almost always the case – understanding the chemical variations in the materials is crucial in planning the blending of stockpiles and developing an adapted production process.

How automation supports cement uniformity control

OLA solutions like the CNA Pentos provide delay-free analysis: materials can be screened without needing to deviate from the production process or require an operator to collect samples. So required process corrections to maintain a constant input of materials is immediate. This also removes possibilities for human error and improves safety, as analysis is conducted without operators needing to approach the process line.

A real case study by a team of researchers working with Switzerland’s Ciments Vigier found that the CNA Pentos OLA could reduce the cement blend’s standard deviation in limestone saturation (LS) by up to 88% during silo filling. Such improvements allow more usage of ARMs and SCMs, as OLA ensures consistency of the performance of the cement blend. For example, it was possible to increase ARM consumption from 5% to 15% of the total raw mix at Ciments Vigier’s plant in Reuchenette, Switzerland.

Further improving OLA efficiency with the O_Blend* control system

Online Control’s O_Blend system combines the various quality measurements obtained using OLA and techniques such as XRF and XRD and acts as an autopilot for the associated instruments. O_Blend is part of the “optimizing quality control system” (OQCS) at the Reuchenette plant, which includes the CNA Pentos and is providing great results in numerous key areas.

It’s proven more accurate than LS-XRF measurements alone, and has reduced kiln fuel consumption by 0.7%, leading to savings of 5kg of CO₂ per ton of clinker. It achieved this while reaching a new ARM consumption record (+9%) and enables operators to leave it in its automatic mode 35% more often than the previous system. The automated system runs for more than 90% of the plant’s production time!

The integration of the CNA Pentos into such control systems enables even greater improvements in throughput, lower energy consumption, and reduced CO2 emissions. Automated analysis in the cement manufacturing context thus provides benefits across the board, from freeing up operators and increasing cost-efficiency to improving output quality and sustainability.

To learn more, read the ISC’s article on automated raw material control, and explore our solutions for the cement industry!

*O_Blend is now also available as a Malvern Panalytical product under the name “Smart Blend”.