Rohrdorfer Zement launches clay pilot plant

Rohrdorfer Zement is beginning a pilot project with its net zero emission team to investigate the process-integrated production of tempered clays. The project includes the development and construction of a pilot plant in the cement plant in Rohrdorf, which is to be integrated into the plant’s operations. The aim is to develop a process that can be transferred to other cement plants and adapted by the entire cement industry. According to the cement producer, the project is funded 50 per cent by the Federal Ministry for Economic Affairs and Climate Protection (BMWK) and the European Union as part of the “NextGenerationEU” programme. 

For cement to be produced in a CO₂-neutral manner, its manufacturing and raw materials must be decarbonised. An important lever in the is the partial replacement of clinker with low-CO₂ or CO₂-free alternatives, including mineral components such as clays. Their binding properties must be activated by thermal treatment, known as annealing, and it is this that will be tested in the pilot plant. 

A special feature of the system is tempering with a flash calcined. The integration into an active cement plant is also a milestone as previous test plants were stand-alone systems that were decoupled from the cement production process. If the integration is successful, the technology can be expected to spread quickly throughout the cement industry, according to Rohrdorfer Zement. 

The Rohrdorfer new zero emission team goes one step further: the system concept pursued aims to use existing waste heat from the clinker production line in order to reduce the primary energy requirement for the thermal treatment of the clay. For the additional amount of heat required, the use of hydrogen is considered, among other things, as a sustainable energy source. After leaving the pilot plant, the exhaust gases generated during operation are returned to the existing gas purification system of the clinker production line. This results in no additional emissions.