@article{article_1463635, title={Ionic Cr(VI) reduction in production of cement and investigation of its effects on cement properties}, journal={Van Yüzüncü Yıl Üniversitesi Mühendislik Fakültesi Dergisi}, volume={2}, pages={14–28}, year={2024}, author={Yönten, Vahap and Akkeçi, Emre}, keywords={Çimento, Dermatit, İndirgeme, Krom (VI).}, abstract={When cement comes into contact with water, the Cr(VI) it contains dissolves in water and may cause contact dermatitis as a result of skin contact. Legal measures are taken to control and reduce health problems that may occur due to the presence of Cr (VI) in cement. In the 2003/53/EC directive prepared by the European Parliament, the upper limit of Cr(VI) content in cement after hydration was determined as 2 ppm and EU sales of cement containing Cr(VI) above this value were prohibited as of 17 January 2005. In our country, it is stated that the soluble chromium contained in the cement should be less than 2 ppm in the Article 47 of Annex 17 of the Regulation on Registration, Evaluation, Authorization and Restriction of Chemicals in bagged cements for handling. In this study, reducing activities of Cr(VI) in cement were determined by using reducing chemicals. In order to reduce the amount of Cr(VI) in cement below the legal limit of 2 ppm, iron sulfate monohydrate (FeSO4.H2O), iron sulfate tetrahydrate (FeSO4.4H2O), ferrous sulfate heptahydrate (FeSO4.7H2O), and 40.26 ppm cement as cement. CEM I 42.5 R portland type cement with chromium content was used. Changes in the physical and chemical properties of cement after reduction were investigated. As a result, it was observed that all of the reducers used in the study had a reducing efficiency of Cr(VI) in cement. It has been determined that ferrous sulfate heptahydrate is a more effective reducing agent, since the amount of Cr(VI) is reduced to 0.34 ppm when 0.2% by mass is used, less amount is used for reduction compared to other chemicals, and changes on cement properties are observed at reasonable levels.}, number={1}, publisher={Van Yüzüncü Yıl Üniversitesi}, organization={Yok}