To provide a stabilization method of phosphorus in a detoxifying tower converting in a short time and safely phosphorus remaining in the detoxifying tower used for making phosphine harmless.
The stabilization method of phosphorus in the detoxifying tower packed with a detoxifying agent used for making toxic gas containing phosphine harmless, comprises a process of circulating a copper nitrate solution through the detoxifying tower for converting phosphorus remaining after making phosphine harmless into a stable compound. The nitric acid ion concentration and the copper ion concentration contained in the circulated copper nitrate solution has a following relationship: a combination of (X, Y) included in the range of a figure surrounded by P1(0.10, 0.05), P2(73, 0.05), P3(105, 0.10), P4(107, 1.0), P5(92, 10), P6(148, 50), P7(99, 50), P8(20, 10), P9(2.0, 1.0), when assuming the X-coordinate as the nitric acid ion concentration, and the Y-coordinate as the copper ion concentration(g/L, in a logarithmic scale).
MABUSE HIROYASU
MAEDA MASAMI
Koichi Kajisaki
Toshihiko Taniguchi