Possible ways of reducing SO_2 emissions when raw materials containing sulphides are used in the cement production process, Part 1

摘要

The emission of sulphur dioxide from plants for manufacturing cement rises if increased percentages of compounds containing sulphur in the form of sulphides are introduced into the process with the raw materials. In this case the SO_2 is released at temperatures below 600 ℃ at which there are still no reaction partners available. It is therefore of interest to work out possible ways of fixing the SO_2 contained in the exhaust gas in the low temperature range of the cement manufacturing process. Drying and grinding represents a process in the low temperature range with known adsorption/absorption. Laboratory investigations underline the important role of the drying regime for absorption of SO_2 in the reaction product during drying and grinding, and show that the extent of the SO_2 release, which takes place with rising reaction temperature through desorption and pyrites decomposition, depends on the SO_2 absorption in the low temperature range. The results provide pointers towards possible ways of optimizing the drying and grinding system.