Residue after the extraction of potassium and chlorine from by-pass dust as a new raw material for the synthesis of low-emission Portland clinker

Abstract

By-pass dusts are waste products formed during the production of Portland clinker. Due to the high amounts of chlorine in by-pass dust, they cannot be reused in cement production. Mineral fertilizer producers have the technology to recover potassium from by-pass dust, during which unwanted chlorine is simultaneously extracted. Due to the high content of non-carbonated CaO in the residue after extracting potassium and chlorine from by-pass dust, this material can be a very valuable ingredient in the production of Portland clinker. This paper aims to present the possibility of producing low-emission Portland clinker using the residue after extracting potassium and chlorine from by-pass dust. Using the maximum amount of extraction residue in the raw material sets from which Portland clinker is produced reduced emissions by 407.6 kg CO2 per Mg of Portland clinker, compared to Portland clinker produced from natural carbonate raw materials. Additionally, cements made from clinkers calcined with extraction residue showed better strength increases after 2, 7, 28, and 90 days of curing compared to reference cement made from Portland clinker calcined with natural carbonate raw materials.