Abstract
Co-processing lime-dried sludge (LDS) in cement kilns is an appropriate technique to solve the problem of LDS disposal and promote the sustainable development for cement industry. However, there were limited studies investigated the effects of feeding points on product quality and cement kiln emissions. In this study, simulated experiments were conducted by dividing the feeding points into high-temperature zones (HTZs) and raw mill (RM). Cement quality and major cement kiln emission characteristics were comprehensively investigated. The results showed that in terms of burnability, compressive strength and microstructure, the optimum co-processing amount of LDS were 9 wt% when feeding at RM, while 6% when feeding at HTZs. Meanwhile, the organic emissions of RM samples were mainly low environmental risk compounds of amides and nitrogenous heterocyclic compounds. Inorganic gaseous pollutions of NOX and SO2 respectively were 8.11 mg/g DS and 12.89 mg/g DS, compared with 7.61 mg/g DS and 4.44 mg/g DS for HTZs'. But, all the cement kiln emissions concentration still much lower than standard requirements. Overall, RM had a bigger LDS co-processing capacity and a higher but acceptable cement kiln emissions. Feeding LDS via RM could disposal larger amount of sludge and provide more alternative materials for cement manufacturing.
- cement kiln
- co-processing
- emissions
- feeding points
- lime-dried sludge
- First received 20 July 2017.
- Accepted in revised form 16 November 2017.
- © IWA Publishing 2017
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