L1 /
10
CH3041
THE PHOSPHORUS
CYCLE II
• Solubility &
volatility of ‘P’ cmpds are low.
• Only a small amount of ‘P’ enters the atmosphere
and this is as dust.
• Most fluxes are as suspended
solids where the orthophosphate
anion PO43- is bound to a cation in insoluble
inorganic material.
• The largest reservoir is sedimentary
rocks.
• A large reservoir exist in phosphate
rock
of which the major ores are apatites of the
general formula Ca5(PO4)3X (X = F, OH).
of which the major ores are apatites of the
general formula Ca5(PO4)3X (X = F, OH).
•The
salts in these ores have low solubilities calcium
phosphate Ca3(PO4)2 Ksp » 10-29
hydroxyapatite Ca5(PO4)3OH Ksp » 10-51
fluorapatite Ca5(PO4)3F Ksp » 10-60
