Titre du document / Document title

Residence time effect on iron perturbation of taranakite formation

Auteur(s) / Author(s)

LIU C. ⁽¹⁾ ; HUANG P. M. ⁽¹⁾ ; ZHOU J. M. ⁽²⁾ ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

⁽¹⁾ Dep. of Soil Science, Univ. of Saskatchewan, 51 Campus Drive, Saskatoon, SK, S7N 5A8, CANADA
⁽²⁾ The Institute of Soil Science, Academia Sinica, P.O. Box 821, 71 East Beijing Road, Nanjing 210008, CHINE

Résumé / Abstract

Taranakite is an important reaction product in the immediate vicinity of phosphate fertilizer bands. The residence time effect on taranakite formation at pH 4.0 and on the iron perturbation of its formation at a Fe(II)/Al molar ratio of 1.2 (Al = 1 x 10^-2 M and NH₄H₂PO₄ = 1 M) was investigated in this study. The crystallization of NH₄-taran-akite involved a phase transformation from irregularly shaped x-ray noncrystalline materials to taranakite. The incorporation of NH⁺₄ ions into taranakite structure was a relatively slow process. The presence of Fe(II) in the solution of the reaction system perturbed the incorporation of NH⁺₄ ions into taranakite structure, especially in the early aging period. Furthermore, the coating or coprecipitation of x-ray noncrystalline iron phosphates with aluminum phosphates appeared to reduce the dissolution of aluminum phosphates, thus, affecting the phase transformation to taranakite. The presence of Fe(II) greatly decreased the rate of taranakite formation and retarded its formation. This is attributed to iron phosphate coatings as impurities on taranakite particles and the subsequent retardation of its crystal growth by interfering the integration of growth units. The impact of the residence time of Fe perturbation of the formation of taranakite in the immediate vicinity of fertilizer zones in soils, especially under reduced conditions, on the transformation and dynamics of P and N in the terrestrial system merits close attention.

Revue / Journal Title

Soil Science Society of America journal   ISSN 0361-5995   CODEN SSSJD4 

Source / Source

2002, vol. 66, n^o1, pp. 109-116 (22 ref.)

Langue / Language

Anglais

Editeur / Publisher

Soil Science Society of America, Madison, WI, ETATS-UNIS  (1976) (Revue)

Localisation / Location

INIST-CNRS, Cote INIST : 6109, 35400009471443.0140