Bleaching Powder

Bleaching is a process of removing colour from a cloth to make it whiter. Bleaching powder has been used for this purpose since long. Chemically, it is calcium oxychloride, CaOCl2.

Manufacture

Raw Material Required

The raw material required for the manufacture of bleaching powder are:

  • Slaked lime, Ca(OH)2
  • Chlorine gas, Cl2

Process

It is manufactured by Hasen-Clever Method. The plant consists of four cylinders made of cast iron with inlet for chlorine near the base. The dry slaked lime, calcium hydroxide is fed into the chlorinating cylinders from the top. It moves down slowly and meets the upcoming current of chlorine. As a result of the reaction between them, it is converted into bleaching power which collects at the bottom.

Ca(OH)2 + Cl2 → CaOCl2 + H2O

Uses

  1. In textile industry for bleaching of cotton and linen.

  2. In paper industry for bleaching of wood pulp.

  3. In making wool unshrinkable.

  4. Used as disinfactant and germicide for sterilization of water.

  5. For the manufacture of chloroform.

  6. Used as an oxidizing agent in chemical industry.