Articles on the cement industry from Global Cement

Around 60% of a cement plant’s CO₂ emissions are from the calcination step. Received wisdom in the sector is that such emissions cannot be avoided and reduction of combustion CO₂ through dry processing, alternative fuels, waste heat recovery or other advanced solutions has historically been preferred. However, the Direct Separation Reactor from Australian firm Calix, which will be used in the Low Emissions Intensity Lime and Cement (LEILAC) project, will tackle the issue of CO₂ emissions from calcination head on. The technology has already been used commercially in the magnesite calcining industry. Peter Edwards spoke to key staff from Calix about the technology and its potential for the cement and lime sectors.

Cement producers around the world are under greater pressure than ever to maintain margins in light of difficult conditions in many markets. Once any apparent technical process solutions have been implemented, what else can be done to improve the performance of cement producers in terms of operational costs, suppliers, staff attitudes and management approaches? Here, we hear about the work of Alexander Proudfoot, a management consulting company with wide experience in the global cement industry, from Angus Maclean, the firm’s Executive Vice President for Client Delivery, Europe.

During 2015 the Austrian cement manufacturer Schretter & Cie GmbH & Co KG modernised its grinding process. The former system with a high pressure grinding roll (HPGR) working in a pre-grinding mode was upgraded to a grinding circuit with an HPGR in semi-finish grinding mode. A compact 2-Stage Koesep air classifier, the latest development of Köppern, based in Germany, was installed. The new combined air classifier was implemented during ongoing operation with total plant downtime of just 40hr. One year after re-commissioning of the grinding system it can be noted that the modernisation improved production, stabilised the process and reduced energy consumption. This article reflects experiences made throughout the first year of operation and shows effects with regard to production and energy consumption.

The Cemex South Ferriby plant has stood proudly on the Humber Estuary in North Lincolnshire, UK for nearly 80 years. Over the years, the river has been a vital lifeline for the plant to bring in raw materials and export cement. However, in December 2013 the plant was completely overwhelmed by a tidal surge, leaving it with major damage. Here, key plant staff describe the damage, the renovation and the plant’s unusual semi-dry Lepol grate production process.

The burning zone of a rotary lime kiln has the highest process and shell temperatures of anywhere in the kiln. Increasing production by increasing burning temperatures necessitates the selection of higher quality basic wear lining brick (improved thermochemical resistance) to optimise the refractory campaign life. Such bricks also have higher conductivity and, with minimal coating formation, shell temperatures are further increased. The resulting high shell temperature can cause shell deformation, increased energy consumption, loosening of the refractory lining and rotational and migration issues. Until now, dedicated insulation linings have not been used in such intensely thermomechanically stressful applications due to their inherent softness and fragility. Rotary kiln lime producers have to tolerate unacceptably high shell temperatures and energy consumption in order to achieve increased production targets. To correct this, a 13mm thick structural insulation board manufactured by Pyrotek, with world’s best thermomechanical properties, was trialed in order to reduce the shell temperatures. Its performance was assessed over a three year campaign.