Chemical Properties
Zinc oxide is yellowish and powder like.
General Description
Crude zinc oxide is a yellow-gray granular solid with no odor. ZINC OXIDE, CRUDE (ENVIRONMENTALLY HAZARDOUS SUBSTANCES, SOLID, N.O.S.)(1314-13-2) has a specific gravity of 4.4. ZINC OXIDE, CRUDE (ENVIRONMENTALLY HAZARDOUS SUBSTANCES, SOLID, N.O.S.)(1314-13-2) is insoluble in water. The primary hazard is the threat posed to the environment. Immediate steps should be taken to limit its spread to the environment. Prolonged inhalation of the dust may result in metal fume fever with symptoms of chills, fever, muscular pain, nausea and vomiting.
Reactivity Profile
ZINC OXIDE is insoluble in water. What little solubility ZINC OXIDE, CRUDE (ENVIRONMENTALLY HAZARDOUS SUBSTANCES, SOLID, N.O.S.) has yields aqueous solutions that are neutral in pH. Intimate mixtures of zinc oxide and chlorinated rubber with or without hydrocarbons or chlorinated solvent react violently, even explosively upon heating [Chem. Trade J., 1962, 151, 672]. Slow addition of zinc oxide to cover the surface of linseed oil varnish caused generation of heat and ignition, [Chem. Trade J., 1933, 92, 278].
Air & Water Reactions
Slowly decomposed(hydrolyzed) in water. Insoluble in water.
Health Hazard
Exposures to zinc oxide metal fume cause several health disorders. The symptoms of toxicity include, but are not limited to, fever, chills, muscle ache, nausea, fever, dry throat, cough; lassitude (weakness, exhaustion), metallic taste, headache, blurred vision, low back pain, vomiting, malaise (vague feeling of discomfort), chest tightness, dyspnea (breathing diffi culty) and decreased pulmonary function. The overexposure to zinc oxide fumes in workplaces produce symptoms known as metal fume fever or “zinc shakes”; an acute, selflimiting condition. Chronic exposure to zinc oxide may cause respiratory tract irritation with nasopharyngitis and laryngitis.
Potential Exposure
Zinc oxide is primarily used as a
white pigment in rubber formulations and as a vulcanizing
aid. It is also used as an antiinflammatory agent; in photo
copying; paints, chemicals, ceramics, lacquers, and
varnishes; as a filler for plastic; in cosmetics; pharmaceuticals,
and calamine lotion. Exposure may occur in the manufacture
and use of zinc oxide and products, or through its
formation as a fume when zinc or its alloys are heated. HC
may have been used as a Choking/Pulmonary Agent.
Fire Hazard
Some may burn but none ignite readily. Containers may explode when heated. Some may be transported hot.
First aid
If this chemical gets into the eyes, remove any
contact lenses at once and irrigate immediately for at least
15 minutes, occasionally lifting upper and lower lids. Seek
medical attention immediately. If this chemical contacts the
skin, remove contaminated clothing and wash immediately
with soap and water. Seek medical attention immediately.
If this chemical has been inhaled, remove from exposure,
begin rescue breathing (using universal precautions, including
resuscitation mask) if breathing has stopped and CPR if
heart action has stopped. Transfer promptly to a medical
facility. When this chemical has been swallowed, get medical
attention. Give large quantities of water and induce
vomiting. Do not make an unconscious person vomit.
Medical observation is recommended for 24 to 48 hours
after breathing overexposure, as pulmonary edema may be
delayed. As first aid for pulmonary edema, a doctor or
authorized paramedic may consider administering a corticosteroid
spray or other inhalation therapy. If metal fume
fever develops, it may last less than 36 hours.
Shipping
UN3077 Environmentally hazardous substances,
solid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous hazardous
material, Technical Name Required.
Incompatibilities
Incompatible with linseed oil, magnesium.
Contact with chlorinated rubber (@ 215C) may
cause a violent reaction. Slowly decomposed by water.
Physical properties
White or yellowish-white powder; odorless; bitter taste; hexagonal crystal; refractive index 2.008; density 5.606 g/cm3; melts at 1,975°C; practically insoluble in water, 1.6 mg/L at about 30°C; soluble in dilute acids, ammonia solu 990 tion, and alkali hydroxides.
Application
ZnO is used primarily for its anti-bacterial and fungicidal properties. Also, in the United States, ZnO is regarded as a Category I skin protectant and a Category III sunscreen.
Definition
zinc oxide: A powder, white whencold and yellow when hot, ZnO; r.d.5.606; m.p. 1975°C. It occurs naturallyas a reddish orange ore zincite,and can also be made by oxidizinghot zinc in air. It is amphoteric,forming zincates with bases. It isused as a pigment (Chinese white) and a mild antiseptic in zinc ointments.An archaic name is philosopher’swool.
Definition
Zincite is a mineral form of zincoxide, ZnO.
Preparation
Zinc oxide is obtained as an intermediate in recovering zinc from minerals (See Zinc, Recovery). The oxide is prepared by vaporizing zinc metal and oxidation of the zinc vapors with preheated air (French process). The oxide can be produced by other processes. Another method involves roasting franklinite and other ores with coal and then oxidizing the product in air.
Manufacturing Process
Most of the ZnO used today is produced from sphalerite,
ZnS, as the starting ore by either the direct, US process, or the indirect, French
process. In the US process a compound containing ZnO is reduced with coal to
zinc vapor, which is oxidized to ZnO powder. The French process takes place in
two steps. Zinc metal is first vaporized and the vapor is then oxidized with the
ZnO powder being collected.
Hazard
Exposure to zinc oxide fumes from welding and other operations can cause metal fume fever. Its symptoms are chills, fever, cough, and tightness in the chest.
Agricultural Uses
Zinc oxide (ZnO) is a zinc fertilizer. It is a white powder
when cold and yellow when hot, and contains
approximately 78% zinc.
Zinc oxide occurs in nature as a reddish-orange colored zincite, and is made by oxidizing hot zinc in air.
It is an amphoteric oxide forming zincates, by reacting
with bases and zinc salts with acids. It is used as a white
pigment and as a mild antiseptic in ointments. An archaic
name of zinc oxide is philosopher's wool.
Foliar applications with zinc oxide reduce the foliage
damage. Zinc oxide, applied by way of seed coatings,
root dips or tree injections, corrects the zinc deficiency.
Dipping potato seeds in 2% zinc oxide suspension
overcomes zinc deficiency satisfactorily. A similar
method is used for pre-plant dipping of the roots of rice
seedlings.
Pharmaceutical Applications
The pharmaceutical and cosmetic industries use ZnO in powders and ointments because of its bactericidal properties. It is also used to form dental cements by its reaction with eugenol.
Zinc oxide is used as a raw material for many products: stearates, phosphates, chromates, bromates, organic dithiophosphates, and ferrites (ZnO, MnO, Fe2O3). It is used as a source of zinc in animal feeds and in electrogalvanization . It is also used for desulfurizing gases.
Industrial uses
Zinc oxide has many uses. By far the most important is in the rubber industry. Almost half the world’s ZnO is used as an activator for vulcanization accelerators in natural and synthetic rubber. The reactivity of the ZnO is a function of its specific surface area, but is also influenced by the presence of impurities such as lead and sulfates. The ZnO also ensures good durability of the vulcanized rubber, and increases its thermal conductivity. The ZnO content is usually 2–5%.
In paints and coatings, zinc oxide is no longer the principal white pigment, although its superb white color is used by artists. It is used as an additive in exterior paints for wood preservation. It is also utilized in antifouling and anticorrosion paints [2.82]. It improves film formation, durability, and resistance to mildew (having a synergistic effect with other fungicides) because it reacts with acidic products of oxidation and can absorb UV radiation.
In the field of glass, ceramics, and enamels, ZnO is used for its ability to reduce thermal expansion, to lower the melting point, and to increase chemical resistance. It can also be used to modify gloss or to improve opacity.
Materials Uses
The highest purity material is calcined with additives such as Bi2O3 and used in the manufacture of varistors. The photoconducting properties of ZnO are used in photoreproduction processes. Doping with alumina causes a reduction in electrical resistance; hence, it can be used in the coatings on the master papers for offset reproduction.
Zinc oxide is used as a catalyst in organic syntheses (e.g., of methanol), often in conjunction with other oxides. It is present in some adhesive compositions.
Synthesis
Zinc ore is roasted and purified at 1000°C. The two methods of manufacture are (1) French, an indirect method and (2) American, a direct method. ZnO is in the form of transparent hexagonal crystals. The refractive index of this material is 2.0 with whiteness due to the scattering of light by the ultrafine particles. The coverage on the skin of ZnO is subordinate to that of TiO2.8 This material is soluble in acid and alkali with good heat and light stability.
Carcinogenicity
In general, genotoxic studies have not
found evidence for mutagenicity of zinc.
