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| Prochnow,Luís Ignácio; Biasioli,Gustavo Marques; Rodella,Arnaldo Antonio; Jesus,Sérgio Luís de; Montes,Célia Regina; Alleoni,Luís Reynaldo Ferracciú. |
| The concentration of orthophosphate ions released from Fe-K-P compounds (Fe3KH8(PO4)6 .6H2O and Fe3KH14(PO4)8 .4H2O) present in superphosphates increases with pH, which initially suggests that the agronomic effectiveness of P fertilizers containing high amounts of these compounds would also increase with soil pH but studies considering activity, instead of concentration, are necessary. With this purpose, both compounds were synthesized under laboratory conditions, characterized by elemental chemical analysis, optical microscopy, X ray diffractometry, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), and used in a solubility study. Solutions of 0.01, 0.05 and 0.1 mol L-1 NaCl with pH adjusted to 3.0, 4.0, 5.0, 5.5, 6.0, 6.5, 7.0... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Phosphate fertilizers; Cationic impurities; Phosphorus activity; Phosphorus bioavailability. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832006000300008 |
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| Francisco,Eros Artur Bohac; Prochnow,Luís Ignácio; Toledo,Maria Cristina Motta de; Ferrari,Viviane Carillo; Jesus,Sérgio Luís de. |
| Optimization in the use of phosphate rocks is important and the residues of fertilizer production in the form of crandallite may be suitable for agronomic use after calcination. With the objective of evaluating the effect of thermal treatment of the aluminous phosphates of the crandallite group as related to solubility, crystalline structure and morphology, samples from the mine residues of three Brazilian phosphate deposits (Tapira-MG, Catalão-GO, and Juquiá-SP) were collected, air-dried, and screened to 100 mesh. Sub samples were thermally treated at 300, 500, 700, and 900°C for 2 hours. Treated and untreated materials were analyzed by X-ray diffraction, scanning electronic microscopy, energy dispersive X-ray spectrometry, and for the total and soluble P... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Calcination; Phosphate fertilizer; Phosphate impurities. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162007000300009 |
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