Rapid automatic potentiometric method for analytical control in the manufacture of extraction phosphoric acid

A rapid automatic method for determination of free sulphuric acid in the manufacture of extraction phosphoric acid from apatite has been developed. It is based on potentiometric titration combined with the Gran approach for linearization of the titration curve. The analysis is done with an automatic potentiometric titrator controlled by an HP-85 microcomputer. BASIC software activates the system to perform the data acquisition and calculations, and the whole operation takes only 7-8 min.