Zinc ammonium chloride

Zinc ammonium chloride is the inorganic compound with the formula (NH4)2ZnCl4. It is the ammonium salt of tetrachlorozincate. It used as a flux in the process of hot-dip galvanizing.[1] [2][3]

Zinc ammonium chloride
Names
IUPAC name
diammonium tetrachlorozincate(2-)
Identifiers
ChemSpider
EC Number
  • 238-687-6
UNII
Properties
Cl4H8N2Zn
Molar mass 243.26 g·mol−1
Density 1.91 g/cm3
Hazards
GHS pictograms
GHS Signal word Danger
H302, H314, H315, H400, H411
P260, P264, P270, P273, P280, P301+312, P301+330+331, P302+352, P303+361+353, P304+340, P305+351+338, P310, P321, P330, P332+313, P362, P363, P391, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Uses

Steel to be galvanized passes through an acidic cleaning process to remove iron oxide "mill scale". After this process, the surface of the steel is very active and oxide layers begin forming immediately upon exposure to the atmosphere. Zinc ammonium chloride flux in aqueous solution is applied to the steel to reduce any oxides that are formed and/or inhibit them from forming altogether. This allows the molten zinc in the proceeding galvanizing step to maximally adhere to and alloy with the surface of the steel. [4] [5]

Precautions

Zinc ammonium chloride is a Class 9 hazardous material (Miscellaneous) according to the U.S. DOT.

References
  1. "Zinc Ammonium Chloride". Chemical Dictionary Online. Retrieved April 25, 2012.
  2. Vulte, H.T. (1902). Laboratory Manual of Inorganic Preparations. p. 72. ISBN 1408608405.
  3. Hironori Matsunaga (1982). "X-Ray Structural Study of the Successive Phase Transitions in Ammonium Tetrachlorozincate, (NH4)2ZnCl4. I. Crystal Structure Determination". J. Phys. Soc. Jpn. 51 (3): 864–872. doi:10.1143/JPSJ.51.864.CS1 maint: uses authors parameter (link)
  4. "The Hot-Dip Galvanizing Process". V&S Hot Dip Galvanzing.
  5. "Galvanizing Fluxes". Zaclon LLC.
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