Fig. 4 Relationships between the amounts of phosphate sorbed on the Al–oxalate precipitate Al(OH)OX5 and the relative amounts of Al and oxalate solubilized, at pH 5.0 and in the presence of increasing tartrate/phosphate molar ratios (see Table 5). The number in parentheses indicates the initial tartrate/phosphate molar ratio. The linear equations describing the relationships are: Psorbed (mmol kg-1) = 1091.7 + -0.2827 Alsolubilized (mmol kg-1); R = 0.9906. Psorbed (mmol kg-1) = 1327.8 + -0.3356 Oxalatesolubilized (mmol kg-1); R = 0.98271
