Can They Substitute Each Other?

   The magnesium oxide and zinc oxide play a role of activating agent in rubber. However, this two has different activity effect in rubber. So they can not interchange with each other.

   Zinc oxide: the trivial name is zinc white, white hexagonal crystal or powder. The proportion is 5.606, and the melting point is 1975°. It is a kind of amphoteric oxide. The zinc oxide is soluble in acids, sodium hydroxide and ammonium chloride solution. And it is insoluble in water or ethyl alcohol. It presents yellow in high temperature, recovers to white after cooling, and sublimates when heats to 1800℃. It can used for the filler of paint and rubber. In medicines, it is used for making ointment, zinc paste, adhesive plaster and so on. The zinc oxide can treat skin wound and play a role of astringent. Heating the zinc spelter can generate zinc vapor. The zinc vapor can directly combine with oxygen, or directly firing zinc carbonate. It can produce zinc oxide.

   Magnesium oxide: It also can be called magnesia. It is white loose powder, odourless and tasteless. This product is insoluble in water and ethyl alcohol. The melting point is 2852℃, boiling point is 3600℃. The magnesium oxide has excellent fire-resistance and insulating property, and can be divided into light magnesium oxide and heavy magnesium oxide. The light magnesium oxide is dense, and white amorphous powder, tasteless, odorless and non-toxic. The density is 3.58g/cm3, difficult to insoluble in pure water and organic solvent. The solubility in water will be increase because of the existence of carbon dioxide. It is soluble in acid and ammonium salt solution. Through a high temperature sintering, it translates into crystal. It can form magnesium carbonate double salt when meets carbon dioxide in the air. The heavy magnesium oxide is tight, white or beige powder. It is easy to combine with water. when exposes in air, it is easy to absorb water and carbon dioxide. Mixing with magnesium chloride solution, it is easy to gel hardening. The light magnesium oxide is mainly used for the accelerant and activating agent of chloroprene rubber and fluororubber.