Ionic Cr(VI) reduction in production of cement and investigation of its effects on cement properties

Vahap Yönten; Emre Akkeçi

Makale detayları

Ionic Cr(VI) reduction in production of cement and investigation of its effects on cement properties

Yazarlar:

Vahap Yönten | Emre Akkeçi

Yayıncı:

Van Yuzuncu Yıl University

Ana Başlıklar:

Fiziksel Kimya (Diğer) | Çevresel Olarak Sürdürülebilir Mühendislik

Dergi:

Van Yüzüncü Yıl Üniversitesi Mühendislik Fakültesi Dergisi Vol.2 Issue 1, pp.14-28

Belge Tipi:

Makale

Yayın Tarihi:

6/2024

Belge Dili:

İngilizce

Document ID (Org No.):

2001321009

pISSN:

3023-5286

Anahtar kelimeler:

Özet:

 When cement comes into contact with water, the CrVI 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 200353EC directive prepared by the European Parliament, the upper limit of CrVI content in cement after hydration was determined as 2 ppm and EU sales of cement containing CrVI 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 CrVI in cement were determined by using reducing chemicals. In order to reduce the amount of CrVI 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 CrVI in cement. It has been determined that ferrous sulfate heptahydrate is a more effective reducing agent, since the amount of CrVI 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.

 When cement comes into contact with water, the CrVI 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 200353EC directive prepared by the European Parliament, the upper limit of CrVI content in cement after hydration was determined as 2 ppm and EU sales of cement containing CrVI 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 CrVI in cement were determined by using reducing chemicals. In order to reduce the amount of CrVI 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 CrVI in cement. It has been determined that ferrous sulfate heptahydrate is a more effective reducing agent, since the amount of CrVI 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.

 When cement comes into contact with water, the CrVI 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 200353EC directive prepared by the European Parliament, the upper limit of CrVI content in cement after hydration was determined as 2 ppm and EU sales of cement containing CrVI 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 CrVI in cement were determined by using reducing chemicals. In order to reduce the amount of CrVI 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 CrVI in cement. It has been determined that ferrous sulfate heptahydrate is a more effective reducing agent, since the amount of CrVI 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.

 Çimento suyla temas ettiğinde içeriğindeki CrVI suda çözünmekte ve deriye teması sonucunda kontakt dermatite neden olabilmektedir. Çimentodaki CrVI varlığı nedeniyle oluşabilecek sağlık sorunlarını kontrol altına alabilmek ve azaltmak için yasal tedbirler alınmaktadır. Avrupa Parlementosunca hazırlanan 200353EC direktifinde, hidratasyon sonrası çimentoda CrVI içeriği üst limiti 2 ppm olarak belirlenmiş ve bu değerin üzerinde CrVI içeren çimentonun AB satışı 17 Ocak 2005 tarihinden itibaren yasaklanmıştır. Ülkemizde ise elleçleme esas torbalı çimentolarda Kimyasalların Kaydı, Değerlendirilmesi, İzni ve Kısıtlaması yönetmeliği Ek 17, 47. maddesinde çimentoda bulunan çözülebilir kromun 2 ppmden küçük olması gerektiği belirtilmektedir. Bu çalışmada, indirgen kimyasallar kullanılarak çimentodaki CrVIyı indirgeme etkinlikleri belirlenmiştir. Çimentodaki CrVI miktarını yasal sınır olan 2 ppm değeri altına indirgemek için kimyasal indirgen olarak demir sülfat monohidrat FeSO4.H2O, demir sülfat tetrahidrat FeSO4.4H2O, demir sülfat heptahidrat FeSO4.7H2O, çimento olarak da 40.26 ppm krom içeriği olan CEM I 42.5 R portland tip çimento kullanılmıştır. İndirgeme sonrasında çimentonun fiziksel ve kimyasal özelliklerine yönelik değişiklikler incelenmiştir. Yapılan çalışmada sonuç olarak kullanılan indirgenlerin hepsinin çimentoda CrVIyı indirgeme etkinliğinin olduğu görülmüştür. Kütlece  0.2 kullanıldığında CrVI miktarının 0.34 ppm değerlerine kadar düşmesi, diğer kimyasallara göre indirgemek için daha az miktarda kullanılması ve çimento özellikleri üzerindeki değişikliklerin makul seviyelerde görülmesi nedeniyle demir sülfat heptahidratın daha etkili indirgen olduğu belirlenmiştir.

Makale detayları

Ionic Cr(VI) reduction in production of cement and investigation of its effects on cement properties

Yazarlar:

Vahap Yönten | Emre Akkeçi

Yayıncı:

Van Yuzuncu Yıl University

Ana Başlıklar:

Fiziksel Kimya (Diğer) | Çevresel Olarak Sürdürülebilir Mühendislik

Dergi:

Van Yüzüncü Yıl Üniversitesi Mühendislik Fakültesi Dergisi Vol.2 Issue 1, pp.14-28

Belge Tipi:

Makale

Yayın Tarihi:

6/2024

Belge Dili:

İngilizce

Document ID (Org No.):

2001321009

pISSN:

3023-5286

Cement

Dermatitis

Reduction

Chromium (VI).Çimento

Dermatit

İndirgeme

Krom (VI).

Sayı

Makale detayları

Yazarlar: Vahap Yönten | Emre Akkeçi

Yayıncı: Van Yuzuncu Yıl University

Ana Başlıklar: Fiziksel Kimya (Diğer) | Çevresel Olarak Sürdürülebilir Mühendislik

Dergi: Van Yüzüncü Yıl Üniversitesi Mühendislik Fakültesi Dergisi Vol.2 Issue 1, pp.14-28

Belge Tipi: Makale

Yayın Tarihi: 6/2024

Belge Dili: İngilizce

Document ID (Org No.): 2001321009

pISSN: 3023-5286

Sayı

Yazarlar:

Vahap Yönten | Emre Akkeçi

Yayıncı:

Van Yuzuncu Yıl University

Ana Başlıklar:

Fiziksel Kimya (Diğer) | Çevresel Olarak Sürdürülebilir Mühendislik

Dergi:

Van Yüzüncü Yıl Üniversitesi Mühendislik Fakültesi Dergisi Vol.2 Issue 1, pp.14-28

Belge Tipi:

Makale

Yayın Tarihi:

6/2024

Belge Dili:

İngilizce

Document ID (Org No.):

2001321009

pISSN:

3023-5286