| abstract |
The alkali chlorine method, which is a conventional method for removing cyanide from soil containing free cyanide, complex cyanide, and a hardly soluble cyanide compound, cannot decompose a heavy metal cyano complex, and the method of thermal decomposition under alkaline conditions uses formic acid as a by-product. Generates ammonia. The present invention provides a method for repairing soil that can completely decompose cyan without these disadvantages. SOLUTION: The slurry liquid is adjusted to pH 10 to 13 with alkali, and after heating and stirring for 30 minutes or more, hypochlorite is dividedly added to the slurry liquid, and free cyanide is added in the pH range and the temperature range of 80 to 100 ° C. React with complex cyanide and poorly soluble cyanide compounds. [Selection diagram] Fig. 1 |