Total concentration of aluminium in equilibrium with gibbsite

62 Total concentration of aluminium in equilibrium with gibbsite. In the above calculation a total concentration may have been specified in which the solubility of a mineral phase may have been exceeded therefore, it would be appropriate to calculate the speciation and total aluminium in equilibrium with a specified mineral phase, e.g. gibbsite. 

In Section 5.2.4.5 the solubility fCso of gibbsite as a reaction with protons was calculated to be 

If this expression is substituted into equation (5.43) for Al3+ and assuming Al3+ = [Al3+], then the [A1]T in equilibrium with gibbsite will be given by the expression 

The results of such a calculation are shown in Fig. 5.4 for several concentrations of acid. 

however, if the component OH- had been used to define the aluminium hydrolysis reactions the PBE equation would have been formulated differently. 

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