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Potassium Chloride Information

Potassium chloride is a colorless, crystalline solid that possesses cubic crystals. It is generally recognized as a potassium fertilizer. The principal source of potassium chloride is the Stassfurt salt deposits, where it occurs as sylvine (KCl), and also as carnallite (KCl.MgCl2.6H2O). Another source is dried seaweed, which contains about 90 per cent potassium chloride.

Potassium chloride is manufactured commercially from the ores sylvine and carnallite.

  1. Preparation: From Sylvine, KCl

    • Sylvine is a mixture of potassium chloride (KCl) and sodium chloride (NaCl). When the boiling-hot saturated solution of the mixed salts in water is cooled, potassium chloride is crystallized and separated out, while the solution left behind contains only sodium chloride.

    Preparation: From Carnallite, KCl.MgCl2.6H2O

    • This ore is always found mixed with sodium chloride and magnesium sulphate. In order to remove sodium chloride and magnesium sulphate from the ore, it is ground and extracted with a hot 20 percent solution of magnesium chloride. Carnallite gets dissolved, while sodium chloride and magnesium sulphate remain unaffected. These are filtered off, and the solution which contains only carnallite is crystallized. In this way, the cubic crystals of KCl are extracted, leaving behind magnesium chloride in the solution.

    Properties

    • The melting point and boiling point of potassium chloride are 768 degrees C and 1,411 degrees C, respectively. Potassium chloride is extremely soluble in water. It closely resembles NaCl (sodium chloride) in most of its properties, except that its solubility increases rapidly with the temperature, and it is fusible even at room temperature.

    Uses

    • Potassium chloride is used in the manufacture of potassium and its compounds.

      It is a potassium fertilizer (K-type fertilizer), since it only supplies potassium (as potassium oxide) to soil. The quantity of potassium oxide found in KCl varies according to the purity of KCl. Usually, 50 to 55 per cent potassium content is found in the salt.

      KCl is also used in medicine, in lethal injections in judicial execution, in scientific experiments and in food processing.

      Potassium chloride was once used as a fire extinguisher, and called a super K-dry chemical.

      KCl is still used as a beta radiation source in radio monitoring equipment calibration.

      Potassium chloride has an application in petroleum and natural gas operations, where it is mixed with water as a completion fluid.

    Potential Health Hazards

    • Breathing in high concentrations of KCl dust could cause serious lung irritation or nasal problems.

      Intake of large amounts of KCl powder can cause vomiting and gastrointestinal irritation.

      If the substance makes contact with skin, it can produce a rash and cause irritation, especially with wet skin.

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