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The Role of Ferrous Sulphate as a Setting Regulator and a Portland Clinker Reduction Agent
Mončeková, Miroslava ; Rovnaníková, Pavla (referee) ; Drábik, Milan (referee) ; Havlica, Jaromír (advisor)
In 2003, the European Community Obligation (directive 2003/5C/EC) regulates a maximal value of soluble hexavalent chromium to 0.0002 % (per weight of dry cement). This limitation leads to modifications of the regular Portland cement by using of suitable reduction agents. Therefore, the possibilities of chromium reduction become a very actual topic. The primary goal of this work is a basic research of the ferrous sulphate influence on hexavalent chromium reduction and also its influence on Portland clinker hydration process. The reduction ability was determined by UV/VIS method. The mechanism and ferrous sulphate influence on Portland clinker hydration process was observed by isothermal calorimetry and mechanical strength tests. XRD method, SEM-EDS analysis and Raman microscopy were used for identification of formed hydration products. Study of hydration mechanism occurring in this system was focused on the divergence observations from the regular Portland cement hydration. Pore solution analysis provided significant information about chromium behavior during the hydration process (substitution and releasing). Chromium incorporation into structure of hydration products during the reduction process was also studied in the pure tricalciumaluminate system with targeted Cr6+ content. This work suggests the possible substitution of the trivalent and hexavalent chromium into structure of monosulphate (AFm) phase.
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The Role of Ferrous Sulphate as a Setting Regulator and a Portland Clinker Reduction Agent
Mončeková, Miroslava ; Rovnaníková, Pavla (referee) ; Drábik, Milan (referee) ; Havlica, Jaromír (advisor)
In 2003, the European Community Obligation (directive 2003/5C/EC) regulates a maximal value of soluble hexavalent chromium to 0.0002 % (per weight of dry cement). This limitation leads to modifications of the regular Portland cement by using of suitable reduction agents. Therefore, the possibilities of chromium reduction become a very actual topic. The primary goal of this work is a basic research of the ferrous sulphate influence on hexavalent chromium reduction and also its influence on Portland clinker hydration process. The reduction ability was determined by UV/VIS method. The mechanism and ferrous sulphate influence on Portland clinker hydration process was observed by isothermal calorimetry and mechanical strength tests. XRD method, SEM-EDS analysis and Raman microscopy were used for identification of formed hydration products. Study of hydration mechanism occurring in this system was focused on the divergence observations from the regular Portland cement hydration. Pore solution analysis provided significant information about chromium behavior during the hydration process (substitution and releasing). Chromium incorporation into structure of hydration products during the reduction process was also studied in the pure tricalciumaluminate system with targeted Cr6+ content. This work suggests the possible substitution of the trivalent and hexavalent chromium into structure of monosulphate (AFm) phase.
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Využití materiálů získaných při odstraňování starých ekologických zátěží
Výzkumný ústav organických syntéz, Centrum ekologie, toxikologie a analytiky, Pardubice-Rybitví ; Petira, Oldřich ; Mejstřík, Viktor ; Čihák, Rostislav ; Držková, Libuše ; Doležalová, Ludmila
Projekt řeší odstraňování a další využití některých typů odpadů současně s odstraněním nebo minimalizací environmentálních a zdravotních rizik. Jedná se o velkoobjemové odpady s nebezpečnými vlastnostmi. Byly zkoumány problémové odpady, které tvoří ekologickou zátěž v masivních množstvích: kontaminovaný síran železnatý z anorganických chemických výrob (anorganické pigmenty), destilační zbytky z výrob organické chemie (polotovary pro širokou škálu následných syntéz), redukční odpad z výrob aromatických aminů (masově užívané meziprodukty, např. barviva). U těchto hmot byly po laboratorním ověření provedeny pilotní zkoušky možného využití.
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