To provide a method for simply, swiftly, cheaply and precisely determining a required amount of a heavy metal treating agent necessary to make a heavy metal in a substance containing the heavy metal insoluble.
The required amount of the heavy metal treating agent is determined by adding the heavy metal treating agent to mixed slurry of the substance containing the heavy metal and water, and measuring the change of the electric potential of the mixed slurry using a second-class oxidation-reduction electrode. The method for determining the heavy metal treating agent determined by setting a weight ratio of water/the substance containing the heavy metal in the mixed slurry at >100 and ≤100,000, and the pH of the mixed slurry at >3.5 and <4.5 obtains a stable and precise result of a measurement, and does not elute the heavy metal when the substance containing the heavy metal is subjected to acid rain.
SAKAKI TAKASHI
SUZUKI NOBUMASA
