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Numerical Evaluation of Granule Size Effect on Dissolution Rate of Potassium Silicates and Potassium Polyphosphate in Aqueous Solution
Author(s) -
Miwa Eitaro,
Kurihara Kiyoshi
Publication year - 1977
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/sssaj1977.03615995004100030044x
Subject(s) - dissolution , granule (geology) , aqueous solution , potassium , chemistry , saturation (graph theory) , nuclear chemistry , kinetics , polyphosphate , analytical chemistry (journal) , reaction rate constant , solubility , mineralogy , inorganic chemistry , materials science , chromatography , phosphate , organic chemistry , physics , mathematics , composite material , combinatorics , quantum mechanics
The rate of potassium dissolution from spherical granules of K 2 O · 4SiO 2 , K 2 O · 5SiO 2 , and (KPO 3 ) n was measured in water, NH 4 Cl and acetic acid solutions. Experimental results were analyzed using first‐order kinetics, involving a rate constant ( k ) and the concentration at saturation ( C s ). The kC s values in H 2 O were 3.65 × 10 −2 , 1.17 × 10 −2 , and 7.08 × 10 −3 mg K/mm 2 per day for K 2 O · 4SiO 2 , K 2 O · 5SiO 2 , and (KPO 3 ) n , respectively. Extremely high kC s values were obtained for the dissolution of (KPO 3 ) n in solvents rich in H + or NH 4 + . Based on these experimental data and assumed values for C s , the whole process of K dissolution from each material at various granule sizes in aqueous solutions was calculated by the equations given by Hixson and Crowell (1931). As much as 83 mg of K from granules up to 3.22 mm in diameter will dissolve within 4 days in 100 ml of 0.001 M NH 4 Cl solution. Only small differences in kC s values were obtained for K 2 O · 4SiO 2 and K 2 O · 5SiO 2 in the solvents used. Potassium dissolution from K 2 O · 5SiO 2 in aqueous solutions will be extended beyond 2‐3 days by increasing granule size to 0.34 mm or greater.