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Chemical and Physical Properties of Iron and Aluminum Phosphates and Their Relation to Phosphorus Availability
Author(s) -
Juo Anthony S. R.,
Ellis Boyd G.
Publication year - 1968
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1968.03615995003200020020x
Subject(s) - phosphate , phosphorus , colloid , aluminium , ferric , mineralogy , quartz , chemistry , aqueous solution , iron phosphate , nuclear chemistry , materials science , inorganic chemistry , metallurgy , organic chemistry
Synthetic, colloidal ferric and aluminum phosphates were crystallized in aqueous medium to form variscite, AlPO 4 · 2H 2 O and strengite, FePO 4 · 2H 2 O. The compounds were identified and characterized by X‐ray, infrared analysis, and electron microscopy. Iron phosphate crystallized at a much faster rate than aluminum phosphate under the same temperature and pressure conditions. Variscite and strengite which were crystallized at 105C for 40 days had specific surface areas of 24.9 m 2 g ‐1 and 1.98 m 2 g ‐1 , respectively. The strengite consisted of single spherical crystals with an average diameter of 6 microns and the variscite consisted of reniform crystalline aggregates with an average diameter of 1.5 micron. In quartz sand cultures, with sudan‐grass ( Sorghum vulgare sudanese ) as the indicator crop, the relative availability of P from the synthetic compounds was: strengite < variscite ⋘ colloidal Fe‐P ⋍ colloidal Al‐P.