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Tripolyphosphate made from wet-process phosphoric acid with the use of a rotary kiln / Regina Kijkowska in Industrial & engineering chemistry research, Vol. 47 N°18 (Septembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6821–6827 Titre : Tripolyphosphate made from wet-process phosphoric acid with the use of a rotary kiln Type de document : texte imprimé Auteurs : Regina Kijkowska, Auteur ; Zygmunt Kowalski, Auteur ; Danuta Pawlowska-Kozinska, Auteur Année de publication : 2008 Article en page(s) : p. 6821–6827 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Tripolyphosphate  Rotary  kiln  Wet-process  phosphoric  acid Résumé : The paper presents results on tripolyphosphate (STPP) preparation with the use of a specially constructed laboratory-scale rotary kiln. The kiln enabled agitation of the material calcined at the temperature range 400−430 °C. Wet-process phosphoric acid WPA-1, taken directly from one of the Polish plants, or WPA-2, imported from Finland, was neutralized with Na2CO3 to obtain a phosphate mixture with the molar ratio Na/P = 5/3. To mimic industrial processing with recycling the product, some of the industrial STPP (form-II) was added and the mixture obtained was fed into the rotary kiln through a vibratory feeder. The calcined product was tripolyphosphate in the crystalline form-II, and that did not depend on concentration of the WPA used, or on the amount of the STPP recycled into the kiln. When a similar phosphate mixture WPA + Na2CO3 + STPP-“recycled” was ignited at 400 °C in a stationary chamber oven, the product obtained was also STPP in form-II. In contrast, when a phosphate mixture WPA + Na2CO3 without STPP-“recycled” was calcined, the phase composition of the product obtained depended on the sort of WPA (WPA-1 or WPA-2) and, in the case of WPA-1, on its concentration. From concentrated WPA-2 the STPP formed more readily than from concentrated WPA-1. Lower H3PO4 concentration and recycling of the STPP into the phosphate mixture, before its ignition, creates favorable conditions for the STPP crystallization. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800412q [article] Tripolyphosphate made from wet-process phosphoric acid with the use of a rotary kiln [texte imprimé] / Regina Kijkowska, Auteur ; Zygmunt Kowalski, Auteur ; Danuta Pawlowska-Kozinska, Auteur . - 2008 . - p. 6821–6827. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6821–6827 Mots-clés : Tripolyphosphate  Rotary  kiln  Wet-process  phosphoric  acid Résumé : The paper presents results on tripolyphosphate (STPP) preparation with the use of a specially constructed laboratory-scale rotary kiln. The kiln enabled agitation of the material calcined at the temperature range 400−430 °C. Wet-process phosphoric acid WPA-1, taken directly from one of the Polish plants, or WPA-2, imported from Finland, was neutralized with Na2CO3 to obtain a phosphate mixture with the molar ratio Na/P = 5/3. To mimic industrial processing with recycling the product, some of the industrial STPP (form-II) was added and the mixture obtained was fed into the rotary kiln through a vibratory feeder. The calcined product was tripolyphosphate in the crystalline form-II, and that did not depend on concentration of the WPA used, or on the amount of the STPP recycled into the kiln. When a similar phosphate mixture WPA + Na2CO3 + STPP-“recycled” was ignited at 400 °C in a stationary chamber oven, the product obtained was also STPP in form-II. In contrast, when a phosphate mixture WPA + Na2CO3 without STPP-“recycled” was calcined, the phase composition of the product obtained depended on the sort of WPA (WPA-1 or WPA-2) and, in the case of WPA-1, on its concentration. From concentrated WPA-2 the STPP formed more readily than from concentrated WPA-1. Lower H3PO4 concentration and recycling of the STPP into the phosphate mixture, before its ignition, creates favorable conditions for the STPP crystallization. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800412q