A method for controlling the amount of aluminum dissolved and a method for producing gypsum based on the method.

摘要

To provide the method for controlling the dissolved amount of aluminum, that can solve a problem of having to use a large number of instruments in the method for quantitatively determining aluminum, and that can solve the problem that not all aluminium having a grasped concentrations form Al-F complex ions since the measurement method based on absorbance is complicated to process an absorption wavelength, even if the aluminum concentration is grasped.SOLUTION: The method for controlling the amount of the dissolved aluminum when the aluminum is dissolved in an acidic sulfuric acid solution containing fluorine comprises: grasping a formation rate S of Al-F complex ions by the formula (1) shown by S=(C0-C1)/C0×100, based on a fluoride ion concentration C0 measured before dissolution of the aluminum and the fluoride ion concentration C1 measured after the dissolution of the aluminum, by using fluoride ion electrode, and controlling the amount of the dissolved aluminum by the formation rate S, and furthermore, the method for producing the gypsum is based on the method for controlling the dissolved amount of the aluminum.SELECTED DRAWING: Figure 1