Related compounds Molar mass 161.47 g/mol Boiling point 740 °C Classification Sulfate | Formula ZnSO4 Density 3.54 g/cm³ Appearance white powder Pubchem 24424 | |
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Zinc sulfate is an inorganic compound and dietary supplement. As a supplement it is used to treat zinc deficiency and to prevention the conditions in those at high risk. Side effects may include abdominal pain, vomiting, headache, and feeling tired.
Contents
It has the formula ZnSO4 as well as any of three hydrates. It was historically known as "white vitriol". All of the various forms are colourless solids. The heptahydrate is commonly encountered.
Medicine
In medicine it is used together with oral rehydration therapy (ORT) and an astringent.
Manufacturing
The hydrates, especially the heptahydrate, are the primary forms used commercially. The main application is as a coagulant in the production of rayon. It is also a precursor to the pigment lithopone.
It is used as in electrolytes for zinc plating, as a mordant in dyeing, as a preservative for skins and leather.
Other
Zinc sulfate is used to supply zinc in animal feeds, fertilizers, toothpaste, and agricultural sprays. Zinc sulfate, like many zinc compounds, can be used to control moss growth on roofs.
Zinc sulfate can be used to supplement zinc in the brewing process. Zinc is a necessary nutrient for optimal yeast health and performance. Although not necessary for low gravity beers as the grains commonly used in brewing already provide adequate zinc. It is a more common practice when pushing yeast to their limit by increasing alcohol content beyond their comfort zone. Before modern stainless steel brew kettles and fermenting vessels and after wood, zinc was slowly leeched by the use of copper kettles. A modern copper immersion chiller is speculated to provide trace elements of zinc. Be careful when adding supplemental zinc to not overdo it. Side effects include "...increased acetaldehyde and fusel alcohol production due to high yeast growth when zinc concentrations exceed 5 ppm. Excess zinc can also cause soapy or goaty flavors." [Sillerova et al. (2012) Journal of Microbiology, Biotechnolgy and Food Sciences 1 (February special issue): 689-695]
Toxicity
Zinc sulfate powder is an eye irritant. Ingestion of trace amounts is considered safe, and zinc sulfate is added to animal feed as a source of essential zinc, at rates of up to several hundred milligrams per kilogram of feed. Excess ingestion results in acute stomach distress, with nausea and vomiting appearing at 2-8 mg/Kg of body weight.
Production and reactivity
Zinc sulfate is produced by treating virtually any zinc containing material (metal, minerals, oxides) with sulfuric acid.
Specific reactions the reaction of the metal with aqueous sulfuric acid:
Zn + H2SO4 + 7 H2O → ZnSO4(H2O)7 + H2Pharmaceutical grade zinc sulfate is produced by treating high purity zinc oxide with sulfuric acid:
ZnO + H2SO4 + 6 H2O → ZnSO4(H2O)7
In aqueous solution, all forms of zinc sulfate behave identically. These aqueous solutions consist of the metal aquo complex [Zn(H2O)6]2+ and SO42− ions. Barium sulfate forms when these solutions are treated with solutions of barium ions:
ZnSO4 + BaCl2 → BaSO4 + ZnCl2With a reduction potential of -0.76, zinc(II) reduces only with difficulty.
When heated over 680 C, zinc sulfate decomposes into sulfur dioxide gas and zinc oxide fume, both of which are hazardous.
Minerals
As a mineral ZnSO4·7H2O is known as goslarite. Zinc sulfate occurs as several other minor minerals Zinc-melanterite (Zn,Cu,Fe)SO4·7H2O (structurally different from goslarite). Lower hydrates of zinc sulfate are rarely found in nature: (Zn,Fe)SO4·6H2O (bianchite ), (Zn,Mg)SO4·4H2O (boyleite), and (Zn,Mn)SO4·H2O (gunningite).