Difference between calcium hypochlorite and bleaching powder

1. What is calcium hypochlorite?

The main components of bleaching powder commonly used in aquaculture are calcium chloride and calcium hypochlorite. Among them: the effective component of bleaching powder that plays a role in disinfection is calcium hypochlorite [ca (CLO) 2], and calcium chloride is a chemical substance that will obviously absorb moisture. Due to the existence of calcium chloride in bleaching powder, the available chlorine in bleaching powder is easily affected and reduced.

Because calcium hypochlorite is the essence of bleaching powder, calcium hypochlorite is also called bleaching powder essence in the market. Compared with bleaching powder, it is pure calcium hypochlorite essence and does not contain calcium chloride and other hygroscopic substances. The chlorine content is about 68%, which is significantly higher than the effective chlorine content of the newly produced non damped bleaching powder. Generally, the disinfection dose is only 0.1~0.2ppm.

In aquaculture and other industries that need disinfection and oxidation, disinfectants that dissolve in water and produce hypochlorite are generally referred to as chlorine containing disinfectants. The germicidal efficacy of chlorine containing disinfectants is closely related to the amount of effective chlorine they contain. The higher the effective chlorine, the stronger the disinfection and oxidation capacity.

2、 Comparison of advantages and disadvantages between bleaching powder and calcium hypochlorite

Advantages of bleach:

It is cheap and has obvious effect on general pathogenic microorganisms.

Disadvantages of bleach:

Due to the strong water absorption of calcium chloride contained in bleaching powder, it is easy to decompose when exposed to light, water, heat, etc., and is not resistant to storage. Especially in humid areas, the available chlorine of bleaching powder will decrease exponentially in about a month. Even lead to the loss of proper disinfection effect.

The principle of bleaching powder deterioration:

Calcium chloride in bleaching powder absorbs water and makes calcium hypochlorite in bleaching powder generate hypochlorite.

3. Hypochlorous acid will decompose into hydrogen chloride and oxygen under light conditions, thus losing effective chlorine.

Advantages of calcium hypochlorite:

Calcium hypochlorite contains very little hygroscopic calcium chloride, so calcium hypochlorite is relatively stable and resistant to storage and transportation (which is very important to ensure the disinfection effect). Compared with bleaching powder, the available chlorine of calcium hypochlorite is stable and high, which has obvious effect on general pathogenic microorganisms. The amount of use in disinfection is small, which reduces the amount of labor.

Disadvantages of calcium hypochlorite:

Since calcium hypochlorite contains a large amount of effective chlorine, protective measures need to be taken during operation.