Potassium bisulfate explained

Potassium bisulfate (potassium bisulphate) is an inorganic compound with the chemical formula KHSO₄ and is the potassium acid salt of sulfuric acid. It is a white, water-soluble solid.

Preparation

More than 1 million tons were produced in 1985 as the initial stage in the Mannheim process for producing potassium sulfate. The relevant conversion is the exothermic reaction of potassium chloride and sulfuric acid:^{[1] [2]}

Potassium bisulfate is a by-product in the production of nitric acid from potassium nitrate and sulfuric acid:^[3]

Chemical properties

Thermal decomposition of potassium bisulfate forms potassium pyrosulfate:

Above 600 °C potassium pyrosulfate converts to potassium sulfate and sulfur trioxide:^[4]

Uses

Potassium bisulfate is commonly used to prepare potassium bitartrate for winemaking.^[5] Potassium bisulfate is also used as a disintegrating agent in analytical chemistry or as a precursor to prepare potassium persulfate, a powerful oxidizing agent.^[6]

Occurrence

Mercallite, the mineralogical form of potassium bisulfate, occurs very rarely.^[7] Misenite is another more complex form of potassium bisulfate with the formula K₈H₆(SO₄)₇.

Notes and References

1. Book: Washington Wiley. Harvey. Principles and Practice of Agricultural Analysis: Fertilizers. 1895. Chemical Publishing Co.. Easton, PA.. 218. Potassium disulfate.. 31 December 2015.
2. Encyclopedia: H. Schultz . G. Bauer . E. Schachl . F. Hagedorn . P. Schmittinger . Potassium Compounds. Ullmann's Encyclopedia of Industrial Chemistry. 2005. Wiley-VCH. Weinheim. 10.1002/14356007.a22_039. 978-3-527-30673-2.
3. Book: Pradyot. Patnaik. Handbook of Inorganic Chemicals. 2003. McGraw-Hill. New York. 978-0-07-049439-8. 636.
4. Book: Iredelle Dillard Hinds. John. Inorganic Chemistry: With the Elements of Physical and Theoretical Chemistry. 1908. John Wiley & Sons.. New York. 547. Potassium disulfate.. 31 December 2015.
5. Book: 978-1-4144-0453-0. Chemical Compounds. Weisblatt. Jayne. Montney. Charles B.. 2006.
6. Book: Brauer, Georg. Handbook of Preparative Inorganic Chemistry Vol. 1, 2nd Ed.. 1963. Academic Press. New York. 978-0-12-126601-1. 392.
7. Web site: Mercallite: Mineral information, data and localities. mindat.org. 2019-05-08.