Greater productivity with lower emissions. These are the demands facing modern cement manufacturers. But when increasing production requires more energy, and the reactions that produce fresh cement manufacture directly release CO2, meeting emission targets can be tough. The solution may well lie with a combination of state-of-the-art automated manufacture and ancient technology…
2000 years ago volcanic ash was a key ingredient of Roman pozzolan cements. And considering pozzolan cement has kept both the Pantheon and the Colosseum standing since then, few can question the fortitude of their engineering! Today many cement manufacturers, such as Zementwerk Berlin, are putting a modern twist on this ancient technology by manufacturing cements with a portion of pozzolanic recycled material.
Incorporating replacement materials, such as micronized limestone, fly ash and blast furnace slag (BFS), in place of a portion of Portland cement both reduces the energy expended on cement production and the amount of CO2 released during manufacture. The net result – cements with a substantially lighter environmental footprint than the standard product. However, manufacturing blends that have different ingredients but deliver the same performance as established grades requires new levels of insight into the factors that affect product performance.
Particle size impacts the rate of hydration of a cement during product use, and hence the early and developed strength that it attains. Controlling replacement material particle size is therefore essential when producing high performance, commercially viable composite products. This is where automated monitoring and control comes in…
The Zementwerk Berlin story
In 2001, Zementwerk Berlin purchased an Insitec online laser diffraction particle sizing system. Installed to directly measure the output of the cement grinding circuit, this system delivered the robust and reliable particle size data required to control the production of Portland cements. Interfacing the analyzer with the plant operating system enabled Zementwerk Berlin to achieve completely closed loop control of the grinding circuit. This automation delivered higher throughput with less manual input required for both analysis and control.
When Zementwerk Berlin began to make slag cements, cements containing a proportion of blast furnace slag the value of this established control system was multiplied. In 2010 a parallel grinding circuit was installed, primarily to grind replacement materials, complete with an Insitec and duplicate control system. The Insitec delivers the particle size data that Zementwerk has found crucial to producing slag cements with well-defined performance.
After a decade of robust and reliable analysis, Zementwerk Berlin upgraded its original Insitec system in 2014 to capitalize on a decade of advances in online technology. The old analyzer is still working well though, and there are plans for it to enjoy a productive retirement!
Closing the loop
As a direct result of process automation it is now 3 to 9 times quicker to switch production from any one of Zementwerk Berlin’s 11 different cement grades to another. The plant operates 24 hours a day with minimal manual input. Plant throughput has increased by 2%, major gain in this high tonnage industry. This powerful fusion of modern innovation and ancient concepts looks set to deliver economic and environmental benefits for many years to come.
Find out more about the benefits of automation with the new collaborative article ‘Reviewing a decade of on-line particle sizing’ in September’s issue of World Cement
Click here to read about Malvern solutions for the Cement industry.