Calcium hypochlorite: preparation, composition/composition information
Firstly, limestone and white coal are added to the lime kiln from the top of the lime kiln according to the ratio of 1:(0.11-0.13) intermittently. The temperature is controlled at 800-1200 C. The lime produced is discharged intermittently from the bottom of the kiln and digested by adding water. The lime containing a small amount of free water is obtained. After ageing for more than 8 days, the lime is sent to the air separation system to remove slag by winch. The powder lime is separated by gas-solid phase by cyclone separator.
Fine slaked lime containing 3%-6% free water is added from the fourth layer of chlorination tower by the winch under the slaking lime silo, chlorine gas (liquefied tail gas of liquid chlorine) is introduced from the first layer of chlorination tower, and the finished bleaching powder is discharged from the first layer of chlorination tower.
The chemical equation is:
2Ca(OH)2+2Cl2_Ca(ClO)2+CaCl2+2H2O
The tail gas discharged from the chlorination tower is absorbed by liquid alkali to form sodium hypochlorite, and the exhaust gas is then emptied.
The preparation methods of calcium hypochlorite are as follows:
Chlorine gas passes into calcium hydroxide solution. Ca(ClO)2.2CaCl2 can be crystallized at high concentration, which is widely used in bleached paper:
2 Ca(OH)2+2 Cl2_Ca(ClO)2+CaCl2+2 H_2O
Or chlorine gas into the mixed solution of calcium hydroxide and sodium hydroxide:
2 Ca(OH)2+3 Cl2+2 NaOH_Ca(ClO)2+CaCl2+2 H_2O+2 NaCl
Composition/Composition Information
Harmful Components: CAS No.
Active Component: Ca(ClO)2-Calcium Hypochlorite
Preparation: chlorine gas into lime milk calcium hypochlorite
2 Cl 2 + 2 Ca (OH) 2 = CaCl 2 + Ca (ClO) 2 + 2 H 2
Calcium hypochlorite is prepared by the reaction of chlorine with calcium hydroxide (lime). Because absolutely dried calcium hydroxide does not react with chlorine, chlorine can only be adsorbed by calcium hydroxide. Therefore, in industry, lime containing less than 1% free water is used for chlorination, and chlorine gas used contains less than 0.06% water. Using the free water in these raw materials, chlorine gas is hydrolyzed to produce acid (HClO, HCl), which is neutralized by lime. Subsequently, the chlorine is hydrolyzed by the water precipitated from calcium hydroxide during chlorination reaction, and more calcium hydroxide is involved in the reaction process, resulting in a series of compounds. Bleaching powder is a complex of these compounds.
Calcium hypochlorite is easy to fail in exposed air: Ca(ClO)2+H_2+CO_2=CaCO_3_+2HClO