[EN]: The use of dicalcium phosphate dihydrate contained in dialytic bags allow this solid to react with clay minerals and demonstrate that the phosphate fertilizers in contact with enough water transforms themselves. When the pH of the systems is lower than 7 the dicalcium phosphate dihydrate transforms to octacalcium phosphate if there is not magnesium in the medium, and to an unknown phosphate when magnesium is present in the system. The most important mechanism through which the phosphate is retained by the c1ays in media of pH near 7 and aproximately 10-2 M in phosphate, seems to be the anionic exchange.

[ES]: El fosfato dicálcico dihidrato sólido encerrado en un saco de diálisis evoluciona a fosfato octocálcico si el pH del medio se mantiene menor a 7 y no hay magnesio presente en las disoluciones. En presencia de magnesio el fosfato dicálcico dihidrato evoluciona a pH superior a 7 a otro fosfato no identificado. En estos medios, y en presencia de minerales de la arcilla, éstos retiran fósforo de la solución, principalmente por un mecanismo de cambio aniónico.

16 páginas, 3 figuras, 4 tablas, 21 referencias.

Peer reviewed