Zinc oxide

Zinc Oxide

Zinc oxide is an inorganic compound with the formula ZnO. It is a white powder that is insoluble in water, and it is widely used as an additive in numerous materials and products including rubbers, plastics, ceramics, glass, cement, lubricants, paints, ointments, adhesives, sealants, pigments, foods, batteries, ferrites, fire retardants, and first-aid tapes.

Chemical Properties

Zinc oxide is an amphoteric oxide. It is nearly insoluble in water but soluble in acids or alkalis. It occurs as white hexagonal crystals or a white powder commonly known as Zinc white. Zinc white crystallizes in the hexagonal system and is essentially the mineral zincite.

Production

Zinc oxide is produced by three main processes: direct, indirect and wet chemical process. The direct or American process starts with diverse contaminated zinc composites, such as zinc ores or smelter by-products. The indirect or French process starts with the metal zinc. The wet chemical process starts with a solution of a zinc salt.

Applications

Zinc oxide has a wide range of applications in various fields. In the rubber industry, it is used as a vulcanization accelerator. In the ceramics industry, it is used to make frits, enamels and glazes. In the cosmetics industry, it is used in products such as baby powders, antiseptic creams, anti-dandruff shampoos, and sunscreen lotions. In the pharmaceutical industry, it is used in products such as ointments, creams, and lotions to protect against sunburn and other damage to the skin caused by ultraviolet light.

Health and Safety

Exposure to zinc oxide in the air, which occurs in the workplace, can result in lung conditions such as metal fume fever. Symptoms of metal fume fever include a metallic taste in the mouth, fever, headache, chest pain, and shortness of breath. Long-term exposure can lead to siderosis, a lung disease which can cause coughing, altered lung function, and reduced pulmonary function.

See Also

• Zinc
• Zincite
• Zinc white
• Metal fume fever
• Siderosis