Zinc Oxide Introduction
Active zinc oxide (ZnO) has a particle size between 1-100 nm. It is
a new type of high-functional fine inorganic product for the 21st
century. It exhibits many special properties, such as
non-migration, fluorescence, piezoelectricity, and the ability to
absorb and scatter ultraviolet rays. By utilizing its wonderful
properties in light, electricity, magnetism, and sensitivity, it
can be used to manufacture gas sensors, phosphors, varistors,
ultraviolet shielding materials, image recording materials,
piezoelectric materials, varistors, high-efficiency catalysts,
magnetic materials, and plastic films.
Zinc Oxide Parameters
| Parameter Name | Unit | Value Range/Description |
| Chemical Formula | - | ZnO |
| Molecular Weight | g/mol | 81.39 |
| Appearance | - | White powder or hexagonal crystals |
| Density | g/cm³ | Approximately 5.60-5.67 (varies with preparation method and purity) |
| Melting Point | °C | 1975 |
| Boiling Point | °C | 2360 (sublimes) |
| Refractive Index | - | Approximately 2.008-2.029 (varies with wavelength) |
| Band Gap | eV | Approximately 3.37 (at room temperature) |
| Purity | % | 99.0%-99.99% (depending on application requirements) |
| Particle Size Distribution | nm | Various sizes available, such as 20nm, 50nm, 100nm, 1μm, etc. |
| Specific Surface Area | m²/g | Typically in the range of 10-150m²/g, depending on particle size |
| Hygroscopicity | - | Low hygroscopicity, but may absorb moisture over time if exposed to
humid conditions |
| Solubility | - | Insoluble in water, slightly soluble in alcohols, soluble in dilute
acids, sodium hydroxide solutions, and ammonium chloride solutions |
| Thermal Stability | - | Stable at high temperatures, but prolonged exposure to high
temperatures may cause discoloration or phase transformation |
| Electrical Conductivity | S/m | As a semiconductor, electrical conductivity varies with doping and
temperature |
| UV Absorption | - | Effectively absorbs UVA and UVB ultraviolet radiation, providing
good sunscreen properties |
| Antibacterial Properties | - | Inhibits the growth of various bacteria and fungi, suitable for
antibacterial materials |
Morphology
Active zinc oxide is a new type of multifunctional inorganic
material with a particle size of about 1 to 100 nanometers. Due to
the refinement of the grains, its surface electronic structure and
crystal structure change, resulting in surface effects, volume
effects, quantum size effects, macroscopic tunnel effects, high
transparency, high dispersibility and other characteristics that
macroscopic objects do not have. According to records, it has been
found that it exhibits many special functions in catalysis, optics,
magnetism, mechanics, etc., making it have important application
value in many fields such as ceramics, chemical industry,
electronics, optics, biology, medicine, etc., and has special
features and uses that ordinary zinc oxide cannot compare with.
Active zinc oxide can be used in the textile field for ultraviolet
light shielding materials, antibacterial agents, fluorescent
materials, photocatalytic materials, etc. Due to the series of
advantages of active zinc oxide and its very attractive application
prospects, the research and development of active zinc oxide has
become the focus of many scientific and technological personnel.
Properties
Zinc oxide is an electronic structure of a semiconductor catalyst.
When a photon with a certain energy or a photon with an energy
greater than the semiconductor band gap Eg is injected into the
semiconductor under light irradiation, an electron is excited from
the valence band NB to the conduction band CB, leaving a hole. The
excited conduction band electrons and valence band holes can
recombine to eliminate the input energy and heat. The electrons are
captured on the surface of the material, and the valence electrons
jump to the conduction band. The holes in the valence band snatch
the hydroxyl electrons in the surrounding environment and turn them
into free radicals. As a strong oxidant, it completes the
degradation of organic matter (or chlorine-containing) and kills
bacteria and viruses.
Preparation
The preparation methods of zinc oxide are divided into three
categories: direct method (also known as American method), indirect
method (also known as French method) and wet chemical method. Many
commercially available zinc oxides are direct or indirect products
with micron-sized particles and small specific surface areas. These
properties greatly restrict their application areas and their
performance in finished products. Yunnan Chemical Metallurgy
Research Institute adopts wet chemical method ,to prepare
nano-scale active zinc oxide. Various zinc-containing materials can
be used as raw materials, and zinc is leached by acid leaching.
After multiple purifications to remove impurities in the raw
materials, basic zinc carbonate is obtained by precipitation, and
finally roasting to obtain active zinc oxide. Compared with the
previous process technology for preparing nano-scale ultrafine zinc
oxide, this new process has the following technical innovations:
1. The reaction kinetics principle under equilibrium conditions is
combined with enhanced heat transfer technology to quickly complete
the roasting of basic zinc carbonate.
2. By adjusting the process parameters, various types of active
zinc oxide products with different purities, particle sizes and
colors can be prepared.
3. This process can use a variety of zinc-containing materials as
raw materials and convert them into high value-added products.
4. A typical green chemical process, an environmentally friendly
process.
Application
Application in rubber industry
It can be used as a functional additive such as vulcanizing
activator to improve the smoothness, wear resistance, mechanical
strength and anti-aging performance of rubber products, reduce the
use of ordinary zinc oxide and extend the service life.
Application in ceramic industry
As milk porcelain glaze and flux, it can reduce the sintering
temperature, improve gloss and flexibility, and has excellent
performance.
Application in national defense industry
Active zinc oxide has a strong ability to absorb infrared rays, and
the ratio of absorptivity to heat capacity is large. It can be used
in infrared detectors and infrared sensors; Active zinc oxide also
has the characteristics of light weight, light color, and strong
wave absorption ability. It can effectively absorb radar waves and
attenuate them, and is used in new wave-absorbing stealth
materials;
Application in textile industry
It has good ultraviolet shielding and excellent antibacterial and
antibacterial properties. When added to fabrics, it can give
fabrics sun protection, antibacterial, deodorization and other
functions;
Application in feed industry
Active zinc oxide, as a nanomaterial, has high biological activity,
high absorption rate, strong antioxidant ability, safety and
stability, and is currently the most ideal zinc source. Using
active zinc oxide to replace high zinc in feed can not only solve
the animal's demand for zinc, but also reduce pollution to the
environment. The use of active zinc oxide can play an antibacterial
and antimicrobial role, while improving animal production
performance;
Applications in coatings, cosmetics and other application fields
Metal oxide powders such as zinc oxide, titanium dioxide, silicon
dioxide, aluminum oxide and magnesium oxide, when these powders are
made into nanometers, the size of the particles is equivalent to or
smaller than the light wave, and the interval between the
conduction band and the valence band increases due to the size
effect, so the light absorption is significantly enhanced. Various
powders have different shielding and reflection efficiencies for
light. When comparing zinc oxide and titanium dioxide, when the
wavelength is less than 350 nanometers (UVB), the shielding
efficiency of the two is similar, but at 350-400nm (UVA), the
shielding efficiency of zinc oxide is significantly higher than
that of titanium dioxide. At the same time, the refractive index of
zinc oxide (n=1.9) is lower than that of titanium dioxide (n=2.6),
and the diffuse reflectivity of light is lower, which makes the
fiber more transparent and conducive to textile dyeing and
finishing.
Active zinc oxide can also be used to make far-infrared reflective
fiber materials, commonly known as far-infrared ceramic powder.
This far-infrared reflective fiber absorbs the heat emitted by the
human body and radiates far-infrared rays of a certain wavelength
range to the human body. In addition to increasing the blood flow
in the subcutaneous tissue of the human body and promoting blood
circulation, it can also shield infrared rays and reduce heat loss.
Therefore, this fiber is better at storing heat and keeping warm
than ordinary fibers.
