For those who understand sodium hydroxide, it should be known that sodium hydroxide is the most commonly used degreaser. Sodium hydroxide will saponify with stearic acid in animal and vegetable oils to form water-soluble sodium stearate. (soap) and glycerol (glycerol), when the sodium hydroxide concentration is too low, the pH is 0.510.5, the sodium stearate is hydrolyzed, the degreasing effect is lowered; the concentration is too high, the sodium stearate and the surfactant will be The solubility is lowered, the washing property is deteriorated, and it is not easy to be washed after degreasing. Therefore, the amount of sodium hydroxide is generally not more than 100 g/L, and usually between 50 g/L and 70 g/L.
The degreasing liquid made of sodium hydroxide is suitable for degreasing of steel, copper and copper alloy, aluminum and aluminum alloy (the degreasing time of aluminum and aluminum alloy should be strictly controlled within 1 minute to avoid corrosion), sodium hydroxide It is a strong corrosive agent. Wear protective equipment when using it. Pay attention to safety. Degreasing wastewater containing sodium hydroxide should be neutralized before it can be discharged.