Mannheim process

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Mannheim process
Process typeChemical
Industrial sector(s)Chlor-Alkali industry
Feedstock Sodium chloride, sulfuric acid
Product(s) Hydrogen chloride, sodium sulfate

The Mannheim process is an industrial process for the production of hydrogen chloride and sodium sulfate from sulfuric acid and sodium chloride. [1] The Mannheim furnace is also used to produce potassium sulfate from potassium chloride. [2] The Mannheim process is a stage in the Leblanc process for the production of sodium carbonate.

Process

The process is conducted in a Mannheim furnace, a large cast iron kiln. Sodium chloride and sulfuric acid are first fed onto a stationary reaction plate where an initial reaction takes place. The stationary plate is up to 6 m (20 ft) in diameter. Rotating rabble arms constantly turn over the mixture and move the intermediate product to a lower plate. The kiln portion of the furnace is constructed with bricks that have high resistance to direct flame, temperature, and acid. The other parts of the furnace are heat and acid resistant. Hot flue gas passes up over the plates carrying out liberated hydrogen chloride gas. The intermediate product reacts with more sodium chloride in the lower, hotter section of the kiln producing sodium sulfate. This exits the furnace and passes through cooling drums before being milled, screened and sent to product storage facilities. [3]

The process involves intermediate formation of sodium bisulfate, an exothermic reaction that occurs at room temperature:

NaCl + H2SO4 → HCl + NaHSO4

The second step of the process is endothermic, requiring energy input:

NaCl + NaHSO4 → HCl + Na2SO4

Temperatures in the range 600-700 °C are required. [3]

Related Research Articles

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Sodium bisulfate, also known as sodium hydrogen sulfate, is the sodium salt of the bisulfate anion, with the molecular formula NaHSO4. Sodium bisulfate is an acid salt formed by partial neutralization of sulfuric acid by an equivalent of sodium base, typically in the form of either sodium hydroxide (lye) or sodium chloride (table salt). It is a dry granular product that can be safely shipped and stored. The anhydrous form is hygroscopic. Solutions of sodium bisulfate are acidic, with a 1M solution having a pH of slightly below 1.

<span class="mw-page-title-main">Potassium bisulfate</span> Chemical compound

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Chlorosulfuric acid (IUPAC name: sulfurochloridic acid) is the inorganic compound with the formula HSO3Cl. It is also known as chlorosulfonic acid, being the sulfonic acid of chlorine. It is a distillable, colorless liquid which is hygroscopic and a powerful lachrymator. Commercial samples usually are pale brown or straw colored.

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<span class="mw-page-title-main">Organosulfate</span> Organic compounds of the form R–O–SO₃ (charge –1)

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<span class="mw-page-title-main">Wenker synthesis</span>

The Wenker synthesis is an organic reaction converting a beta amino alcohol to an aziridine with the help of sulfuric acid. It is used industrially for the synthesis of aziridine itself.

<span class="mw-page-title-main">Ammonium bisulfate</span> Chemical compound

Ammonium bisulfate, also known as ammonium hydrogen sulfate, is a white, crystalline solid with the formula (NH4)HSO4. This salt is the product of the half-neutralization of sulfuric acid by ammonia.

Sodium pyrosulfate is an inorganic compound with the chemical formula of Na2S2O7. It is a colorless salt. It hydrolyse in water to form sodium bisulfate with a chemical formula of NaHSO4 which has a pH of around 1.

<span class="mw-page-title-main">Benzenesulfonic acid</span> Chemical compound

Benzenesulfonic acid (conjugate base benzenesulfonate) is an organosulfur compound with the formula C6H6O3S. It is the simplest aromatic sulfonic acid. It forms white deliquescent sheet crystals or a white waxy solid that is soluble in water and ethanol, slightly soluble in benzene and insoluble in nonpolar solvents like diethyl ether. It is often stored in the form of alkali metal salts. Its aqueous solution is strongly acidic.

<span class="mw-page-title-main">2-Nitrochlorobenzene</span> Chemical compound

2-Nitrochlorobenzene is an organic compound with the formula ClC6H4NO2. It is one of three isomeric nitrochlorobenzenes. It is a yellow crystalline solid that is important as a precursor to other compounds due to its two functional groups.

References

  1. Helmold Plessen (2000). "Sodium Sulfates". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a24_355. ISBN   978-3-527-30673-2.
  2. H. Schultz; G. Bauer; E. Schachl; F. Hagedorn; P. Schmittinger (2005). "Potassium Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a22_039. ISBN   978-3-527-30673-2.
  3. 1 2 Riegel, Emil Raymond (1974). Kent, James Albert (ed.). Riegel's Handbook of Industrial Chemistry (7th ed.). New York: Van Nostrand Reinhold. p.  132. ISBN   978-0-442-24347-0.