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The Activity Concept of Phosphate‐Rock Solubility
Author(s) -
Chien S. H.,
Black C. A.
Publication year - 1975
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/sssaj1975.03615995003900050021x
Subject(s) - solubility , solubility equilibrium , phosphate , phosphate minerals , phosphorite , apatite , carbonate , mineralogy , extraction (chemistry) , chemistry , geology , inorganic chemistry , chromatography , organic chemistry
Variously treated samples of a finely ground Florida phosphate rock were equilibrated with dilute HCl solutions, and the ion‐activity product of the carbonate apatite mineral in the phosphate rock was then determined from analyses made on the solutions. Constant ion‐activity products or solubility‐product constants were found within a certain pH range in each instance. The solubility, as reflected by the numerical value of the constant, decreased with an increase in the proportion of the phosphate rock dissolved in the solubility determination or prior thereto. After a certain portion of the phosphate rock had been dissolved, however, no further decrease in solubility was found with further extraction of the phosphate rock. These results are similar to those obtained previously with synthetic hydroxyapatite and were interpreted in the same way, namely, that the solids are not uniform but exist in a range of activities.