What are the additives commonly used in industrial cleaning agents?


Release time:

2021-01-15

Oxidants commonly used in industrial cleaning agents
Sodium nitrite

Name: sodium nitrite Molecular formula: NaNO2
Relative density: 2.168 Relative molecular mass: 69.00
Physical properties: white or light yellow rhombic crystal, odorless, easily soluble in water, insoluble in ethanol or ether, alkaline aqueous solution, easy to be oxidized in the air.
Uses: can be used as chemical cleaning printing agent, after pickling, washing or rinsing the metal surface exposed to the atmosphere, very vulnerable to corrosion, the use of sodium nitrite solution treatment, so that the metal surface to generate a protective film, is commonly used "passivation" method.
During treatment, the content of sodium nitrite in passivation injection is usually 1.0~2.0, its pH value is adjusted to 9~10 with ammonia water, the temperature of passivation solution is maintained at 50~60 ℃, and the printing cycle time is 6~10h, then the passivation solution is drained and washed with demineralized water to avoid corrosion caused by residual sodium nitrite.
The passivation method is safe, easy to operate, and can form a dense, steel gray protective film on the surface of the fresh metal after pickling.
In the passivation treatment should pay attention:

① Use a cleaning pump to circulate the passivation demineralized water in the cleaning system and heat it to the required temperature.

Add ammonia to the passivation water, so that the pH value of the passivation water quickly increased to 9~10.

③ The sodium nitrite required for passivation is added at one time in the continuous circulation of passivation water.

The passivation temperature should be determined frequently during the passivation process, and the concentration of sodium nitrite in water samples should be determined.