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Reaction mechanism and kinetic analysis of the decomposition of phosphogypsum via a solid-state reaction / Liping Ma in Industrial & engineering chemistry research, Vol. 49 N° 8 (Avril 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 8 (Avril 2010) . - pp. 3597–3602 Titre : Reaction mechanism and kinetic analysis of the decomposition of phosphogypsum via a solid-state reaction Type de document : texte imprimé Auteurs : Liping Ma, Auteur ; Ping Ning, Auteur ; Shaocong Zheng, Auteur Année de publication : 2010 Article en page(s) : pp. 3597–3602 Note générale : Indusrrial Chemistry Langues : Anglais (eng) Mots-clés : Reaction  Mechanism  Kinetic  Analysis  Decomposition  Phosphogypsum  Solid-State Résumé : Phosphogypsum decomposition is very complex because of its complicated compounds. In this study, using high-sulfur-concentration coal as a reducer, thermogravimetric analysis, differential thermal analysis, scanning electron microscopy, and X-ray diffraction were used to characterize the decomposition process of phosphogypsum in a nitrogen atmosphere at different conditions. Mechanism analysis and experiment results showed that the amount of the intermediate production of CaS depended on the heating rate and the size of coal used, which was produced mainly through the reaction between CaSO4 and C, and production would decrease with an increase of the coal size. 60 mesh was a suitable size of coal for phosphogypsum decomposition to get high recovery of the main production of CaO. Using Kissinger, Flynn−Wall−Ozaw, and Coats−Redfem methods, the mechanism model of phosphogypsum decomposition was confirmed, the decomposition process belonged to the core-form and growing mechanism (n = 2), and the kinetic model was dα/dt = 1.6 × 1016e−475.99×103/RT × 2(1 − α)[−ln(1 − α)]1/2, where α is conversion. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901950y [article] Reaction mechanism and kinetic analysis of the decomposition of phosphogypsum via a solid-state reaction [texte imprimé] / Liping Ma, Auteur ; Ping Ning, Auteur ; Shaocong Zheng, Auteur . - 2010 . - pp. 3597–3602. Indusrrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 8 (Avril 2010) . - pp. 3597–3602 Mots-clés : Reaction  Mechanism  Kinetic  Analysis  Decomposition  Phosphogypsum  Solid-State Résumé : Phosphogypsum decomposition is very complex because of its complicated compounds. In this study, using high-sulfur-concentration coal as a reducer, thermogravimetric analysis, differential thermal analysis, scanning electron microscopy, and X-ray diffraction were used to characterize the decomposition process of phosphogypsum in a nitrogen atmosphere at different conditions. Mechanism analysis and experiment results showed that the amount of the intermediate production of CaS depended on the heating rate and the size of coal used, which was produced mainly through the reaction between CaSO4 and C, and production would decrease with an increase of the coal size. 60 mesh was a suitable size of coal for phosphogypsum decomposition to get high recovery of the main production of CaO. Using Kissinger, Flynn−Wall−Ozaw, and Coats−Redfem methods, the mechanism model of phosphogypsum decomposition was confirmed, the decomposition process belonged to the core-form and growing mechanism (n = 2), and the kinetic model was dα/dt = 1.6 × 1016e−475.99×103/RT × 2(1 − α)[−ln(1 − α)]1/2, where α is conversion. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901950y

Thermal and kinetic analysis of the process of thermochemical decomposition of phosphogypsum with CO and additives / Liping Ma in Industrial & engineering chemistry research, Vol. 51 N° 19 (Mai 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6680-6685 Titre : Thermal and kinetic analysis of the process of thermochemical decomposition of phosphogypsum with CO and additives Type de document : texte imprimé Auteurs : Liping Ma, Auteur ; Yalei Du, Auteur ; Xuekui Niu, Auteur Année de publication : 2012 Article en page(s) : pp. 6680-6685 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Additive  Kinetics Résumé : Phosphogypsum (PG) is a waste byproduct from the processing of phosphate rock by the "wet add method" of fertilizer production. One of the main methods for reusing PG is to decompose and recycle Ca and sulfur contained in it. However, the decomposition reaction process is very complex because of its complicated contents, and very high temperature is needed for the reaction. In this paper, to decrease the reaction temperature, CO as a main reducer and some additives were added in the decomposition process. Results show that the decomposition temperature will decrease from 1000 to 809 °C with pure CO. When CaCl2 is used as an additive, the decomposition temperature can decrease to 790 °C, and at the same time the reaction rate will be increased, the main product being CaS at this condition. The thermal and kinetic action of this process has also been discussed. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25900222 [article] Thermal and kinetic analysis of the process of thermochemical decomposition of phosphogypsum with CO and additives [texte imprimé] / Liping Ma, Auteur ; Yalei Du, Auteur ; Xuekui Niu, Auteur . - 2012 . - pp. 6680-6685. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6680-6685 Mots-clés : Additive  Kinetics Résumé : Phosphogypsum (PG) is a waste byproduct from the processing of phosphate rock by the "wet add method" of fertilizer production. One of the main methods for reusing PG is to decompose and recycle Ca and sulfur contained in it. However, the decomposition reaction process is very complex because of its complicated contents, and very high temperature is needed for the reaction. In this paper, to decrease the reaction temperature, CO as a main reducer and some additives were added in the decomposition process. Results show that the decomposition temperature will decrease from 1000 to 809 °C with pure CO. When CaCl2 is used as an additive, the decomposition temperature can decrease to 790 °C, and at the same time the reaction rate will be increased, the main product being CaS at this condition. The thermal and kinetic action of this process has also been discussed. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25900222