METHOD AND DEVICE FOR DECONTAMINATING METAL WASTE

PURPOSE:To increase the reaction speed, prevent a decontaminating liquid from evaporating and economically removing contaminants sticking on the surface of metal wastes by attaching a foamy decontaminating liquid containing acid on the surface of the metal wastes and keeping it for a prescribed time. CONSTITUTION:After injecting a decontaminating liquid containing acid such as hydrochloric acid and nitric acid and a surface active agent from a decontaminating liquid supplying tank 2 to a foam generator 5 through a decontaminating liquid circulation tank 3, and blowing compressed air into the decontaminating liquid to foam it, the decontaminating liquid is supplied to a solution tank 1. Then, the soaking of a contaminated metal in the foamed decontaminating liquid progresses the dissolving reaction, and the generated solution heat is insulated with the foamy decontaminating liquid and accumulates in the solution tank 1 to boost the reaction. In this case, it is preferable that the diameter of a foam is approximately 0.1 to 2mm, and the ratio of liquid to a foam is 1 to 10vol.%. If the diameter of a foam and the ratio of liquid to a foam are too large, the quantity of acid becomes insufficient. On the other hand, if they are too small, adiathermancy becomes insufficient and the dissolving efficiency declines. Subsequently, after a defoamer 8 defoams the generated gas, it is released to the air through a scrubber 9, a HEPA filter 10 and a blower 11.