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Chinese Agricultural Science Bulletin ›› 2007, Vol. 23 ›› Issue (11): 224-224.

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Characteristics of Dissolution Kinetics of Phosphorus and Calcium from Phosphate Rocks

Rao Wei, Wang Shenyang, Liu Fang, Wang Daizhang   

  • Online:2007-11-05 Published:2007-11-05

Abstract: Characteristics of dissolution kinetics of phosphorus and calcium from phosphate rocks (PRs) by 1 M NH4OAC (pH4.8) acidic solution were investigated by batch methods in laboratory. It indicated that dissolution kinetics of phosphorus could be divided into two stages which was fast reactive process during 0~30 min and slow reactive process after 30 min. Phosphorus dissolution kinetics of the rocks were well described by the Elovich equation. The rates of phosphorus dissolution were highly correlated to citric acid soluble P which was influenced by the amounts of SiO2 and CaCO3. Calcium dissolution from PRs could be also fitted by the Elovich equation and was relative to free calcium carbonate in the rocks. The concentration of Ca dissolution from PR1, different from the others, could partly originate from the dissolution of free calcium carbonate. So the direct applications of PRs would simultaneously supply the phosphorus and calcium nutrition for plants.

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