CHEMICAL CLEANING METHOD AND CHEMICAL CLEANING APPARATUS

WIPO Patent Application WO/2020/217666

A1

The purpose of the present invention is to provide a chemical cleaning method which makes it possible to remove residues generated in chemical cleaning using a sulfur-containing neutral cleaning agent. The chemical cleaning method according to the present disclosure is to clean equipment, as a cleaning target, using a metal matrix as a structural member. The method comprises a neutral cleaning step (S2) of cleaning an inside of the cleaning target by a main agent that dissolves scales containing a metal oxide, and a neutral cleaning agent containing a sulfur element, an oxidizing treatment step (S4) of, after the neutral cleaning step (S2), supplying an oxidizing agent to the inside of the cleaning target, and a dissolving treatment step (S6) of, after the oxidizing treatment step (S4), supplying an oxide solution to the inside of the cleaning target, the oxide solution being regulated using a pH regulator showing basicity to have a pH of 2.5-7.0. The oxide solution contains a chelating agent, an organic acid having a chelating effect, and a solubilizer selected from organic acid salts having a chelating effect.

WADA TAKAYUKI (JP)
SHIMBO YOICHI (JP)
OTSUKA MIZUKI (JP)
EGAWA KAORU (JP)
NOGUCHI YOSHINORI (JP)
UEDA ATSUYOSHI (JP)
HATTORI SEIYA (JP)
ISHIKAWA MAKOTO (JP)

PCT/JP2020/006251

October 29, 2020

February 18, 2020

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MITSUBISHI POWER LTD (JP)
KYOEISHA CHEMICAL CO LTD (JP)

B08B3/08; C23G1/08; B08B9/032; C23G3/04; F28G9/00

WO2016002516A1

2016-01-07

JPH01159388A	1989-06-22
CN102703917A	2012-10-03
CN104975300A	2015-10-14

FUJITA, Takaharu (JP)

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