Chemicals Based Technologies - Potassium Chlorate

Introduction

Potassium chlorate, an important salt of potassium widely used for manufacture of safety matchesIt is also used in pyrotechniques, pharmaceutical industries and for other minor uses.

The major consumption of potassium chlorate is in the manufacture of safety matches. The potassium chlorate content in match head composition varies from 50-55%. Generally, 6-8 kg. of potassium chlorate is used per 100 gross of match containing 144 boxes each. In pyrotechnics potassium chlorates may be mixed with certain organic compounds such as lactose to give a relative cool flame so that certain dyes may be incorporated in the mixture to give coloured flames. Potassium chlorate is also used in the explosive percussion caps, in pharmaceutical industry and dyes as oxidising agent.

Process

The manufacture of Potassium chlorate is carried out by electrolysis of aqueous acidic solution of potassium chloride. The electrolyte contains potassium chloride and potassium dichromate. Potassium dichromate is used for the cathodic reduction process of chlorate formation by an electrochemical reaction from hypochlorite. In general in well designed system, electrolysis of chloride is carried out by electrochemical oxidation of chloride to hypochlorite ions at the anode. Further conversion of hypochlorite to chlorate takes places as a chemical reaction. To achieve high current efficiencies electrolysis is carried out in specially designed electrolytic cells with integral reactors. Electrolysis shall be carried out with controlled pH at a temperature of 70-75 degree C. Electrolyte shall be continuously fed in parallel to all cells and from the cells, over flow shall be received in RCC tile/lined tanks from where the solution is cooled to 55-50 degree C in HDPE cooling tower by air. From the cooling tower basin the electrolyte flow through a series of crystallising pans which are RCC tile lined where the salt separates out and accumulates. From time to time the salt is collected manually by unskilled labour centrifuged and washed. The recovered salt from centrifuge shall be of required purity which shall be dried, pulverised and bagged. Mechanisation for conveying, choice of centrifuge and handling operation can be designed to minimise labour and supervisory requirement.

Properties and Specifications

Potassium chlorate, having a molecular weight of 122.56, is a colourless solid and soluble in water. Its solubility ranges from 3.3 gm at 0oC, 57 gms at 1000C in 100 gms of water. Specific gravity of KClO3 is 2.32 and melting point 3680 C. The product confirms to IS : 1987.

The Bureau of Indian Standard has specified general properties of potassium chlorate (grade II ) suitable for match industry as given below :

Advantages

• Low capital investment
  
• High employment potential
  
• Maximum use of local raw materials and manpower resources
  
• Adaptable levels of sophistication
  

Plant Parameters

Raw Material (Tonne per Tonne of Product)

Utilities (Per day)

Plant & Machinery

For further information please contact :

National Research Development Corporation
( A Government of India Enterprise )
20-22, Zamroodhpur Community Center
Kailash Colony Extension
New Delhi 110 048. India
Tel: 91-11-26419904, 26417821, 26480767, 26432627
Fax: 011-26231877, 26460506, 26478010
Website: www.nrdcindia.com

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