Chelate type decisive method of the necessary addition quantity of the heavy metal fixation medicine and decision method and device null of the heavy metal fixation effect of the processing

摘要

PROBLEM TO BE SOLVED: To easily and exactly decide the adequate amount of addition for preventing the elution of heavy metals by adding a chelating agent to heavy metal-containing ash and to easily and exactly decide a heavy metal immobilization effect relating to the treated ash subjected to the elution preventive treatment of the heavy metals by adding the chelating agent to the heavy metal- containing ash.;SOLUTION: A specified amount of the chelating agent is added to a water slurry of heavy metal-containing ash and its ORP is measured with lapse of time. The positive change rate of the ORP after the addition of the chelating agent is determined and the necessary amount of addition of the chelating agent is determined from this change rate. The positive change rate of the ORP when the chelating agent is added to the water slurry of the treated ash is measured and this change rate is compared with a preset value. The heavy metal immobilization effect of the treated ash is decided in accordance with the result thereof.;COPYRIGHT: (C)2002,JPO