| 摘要 |
<p>A cooling H2O system, having Fe2O3 and hardness deposited on the internal metal surfaces, is cleaned by a 2-stage method: an alkali metal or NH4 salt of an amino polycarboxylic acid is added to bring the pH to 7-12 and dissolve and complex the hardness deposits; after circulation, a mixture of the alkali metal or NH4 salt of an aminopolycarboxylic acid and an acidifying agent is added to dissolve and complex the Fe2O3 deposits and bring the pH to 3-6. After circulation, the cleaning soln. is displaced by make-up H2O. The process removes Fe2O3 and hardness from cooling H2O systems, such as an air-conditioning system.</p> |
