Zinc Oxide Introduction
Zinc oxide (ZnO), commonly known as zinc white, is an oxide of
zinc. It is insoluble in water, but soluble in acid and strong
alkali. It is yellow at high temperature, turns white after
cooling, and sublimates at 1800℃. The zinc oxide lattice is of ZnS
type, oxygen is in the tetrahedron formed by zinc, and zinc is also
in the tetrahedron of oxygen, and the coordination number is 4. It
is a strong ultraviolet absorber and is used in industry as a
reinforcing agent for rubber products, a white pigment, a plastic
filler, a paint colorant, and as the main component of emollients,
ointments, and zinc pastes.
Specifications
Item | Specification |
Chemical Formula | ZnO |
Molecular Weight | 81.38 g/mol |
Appearance | White powder |
Purity | ≥99.9% |
Particle Size | 20-50 nm (Nanometer) |
Specific Surface Area | 20-30 m²/g |
Melting Point | 1975°C |
Density | 5.606 g/cm³ |
Solubility | Insoluble in water |
Differences between direct zinc oxide, indirect zinc oxide, and
nano zinc oxide
Zinc oxide production can be divided into three types according to
its production method: indirect zinc oxide, direct zinc oxide, and
active zinc oxide.
1.Direct zinc oxide is mostly made of zinc ore, zinc ash, and zinc
concentrate. It is oxidized and roasted at high temperature and
then reduced to zinc vapor by coal. Zinc vapor is oxidized with hot
air to obtain zinc oxide. The product purity of this process is
low, generally between 75% and 95%, and the impurity content is
high.
2.The raw material of indirect zinc oxide is metal zinc ingot or
zinc slag obtained by smelting. Zinc is converted into zinc vapor
at a high temperature of 1000°C in a graphite crucible, and then
oxidized by the blown air to produce indirect zinc oxide, and zinc
oxide particles are collected after the cooling tube.
3.The indirect method was promoted by French scientist Leclerc in
1844. The indirect zinc oxide production process is simple, and the
cost is greatly affected by the raw materials. The diameter of zinc
oxide particles produced by the indirect method is between 0.1 and
10 microns, and the purity is between 99.5% and 99.7%. The higher
the purity, the heavier the unit mass.
Chemical properties
Chemical stability: Zinc oxide has high chemical stability and can
remain stable in harsh environments such as high temperature, high
pressure, strong acid, and strong alkali. This stability makes zinc
oxide widely used in many industrial fields.
Amphoteric oxide properties: Zinc oxide is an amphoteric oxide that
can react with both acid and alkali.
Catalytic effect: Zinc oxide has a certain catalytic activity and
can be used as a catalyst to participate in various chemical
reactions and accelerate the reaction process.
Overview of rubber uses:
①Active zinc oxide is mainly used as a reinforcing agent for rubber
to make the rubber have good corrosion resistance, tear resistance,
elasticity and elongation.
②It is used as an accelerator for rubber vulcanization process. It
is a multifunctional rubber compounding agent, mainly used as a
vulcanization activator and reinforcing agent for natural rubber,
synthetic rubber and latex.
③When used as a vulcanization activator, it is evenly distributed
in the rubber material, has a large contact area with hydrogen
sulfide, and has a greater opportunity for interfacial reaction. In
addition, this active zinc oxide product has a catalytic effect of
active substances, which makes the conversion rate of zinc oxide to
zinc sulfide high.
④As a vulcanization oxidant, its function is to enhance the
activity of the accelerator, reduce the amount of accelerator, and
shorten the vulcanization cycle.
⑤It can accelerate the vulcanization speed, improve the thermal
conductivity of the vulcanized rubber, and make the vulcanization
more thorough.
⑥In the rubber industry, especially in the production of
transparent rubber products, active zinc oxide is an excellent
vulcanization active agent.
Advantages
1. Superior Quality: Produced with advanced direct-method technology, ensuring
consistent quality and purity.
2. Versatility: Suitable for multiple industries such as rubber, ceramics, and
cosmetics.
3. Environmentally Safe: Low heavy metal content and safe for a wide range of
applications.
4. Excellent Performance: Provides enhanced reinforcement, thermal stability, and UV
protection.
Applications
1. Rubber Industry: Used as a reinforcing agent, activator, and vulcanization
accelerator.
2. Ceramics: Improves whiteness, strength, and thermal stability.
3. Paints & Coatings: Acts as a pigment and anti-corrosion agent.
4. Cosmetics: Used in sunscreens and skincare products as a UV absorber.
5. Pharmaceuticals: Functions as an antiseptic and astringent in ointments.
6. Agriculture: Serves as a micronutrient in fertilizers and animal feed
additives.
Production Technology
The direct method, also known as the French process, involves the
following steps:
1. Raw Material Selection: High-purity zinc materials such as zinc ore or zinc scrap are
used.
2. Smelting: Zinc is heated and vaporized.
3. Oxidation: Zinc vapor reacts with oxygen in a controlled environment to
produce fine zinc oxide powder.
4. Collection and Processing: The resulting ZnO is collected, filtered, and classified to
ensure quality and uniformity.
Theory
The production of Zinc Oxide via the direct method is based on the
principle of oxidation of metallic zinc in the presence of oxygen.
The chemical reaction is:
2Zn + O₂ → 2ZnO
This process ensures the formation of high-purity zinc oxide with
uniform particle size.
Service
1. Technical Support: Provide guidance on product application and usage.
2. Customization: Tailor specifications based on customer requirements.
3. Sample Availability: Free samples for testing and evaluation.
4. Logistics: Efficient shipping and delivery services.
Packaging & Storage
1. Packaging: Packed in 25 kg bags or 1 MT jumbo bags. Custom packaging is
available upon request.
2. Storage: Store in a dry, cool, and ventilated place. Avoid exposure to
moisture and direct sunlight.
Precautions
1. Avoid inhalation of zinc oxide powder; use proper protective
equipment.
2. Handle with care to prevent contamination or spillage.
3. Follow local regulations for disposal of waste materials.
4. Keep away from acidic substances to avoid chemical reactions.
