Zinc oxide 1314-13-2 manufacturer

Zinc oxide (ZnO), commonly known as zinc white, is an oxide of zinc. Insoluble in water, soluble in acids and strong bases. Zinc oxide is a common chemical additive, widely used in plastics, silicate products, synthetic rubber, lubricating oil, paint coatings, ointments, adhesives, food, batteries, flame retardants and other products in the production.

Function in pigment coating

The refractive index of zinc oxide is higher, and it has the ability to absorb ultraviolet light, and its coloring power and hiding power are strong, but the color is pure white, not pulverized, and has good light resistance and heat resistance.

It can form coordination compounds with carboxylate ions in the coating, which can reduce the sensitivity of water in the coating. Therefore, zinc oxide can improve the weatherability and pulverization resistance of the coating, which is suitable for exterior wall coating.

Zinc oxide has mildew resistance and can inhibit the growth of microorganisms and fungi. Generally speaking, ceramics, cans and barrels are coated with indirect zinc oxide with small particle size and high purity; Interior coating, latex coating is multi-purpose needle-like direct method zinc oxide, so that the oil absorption value is higher, can improve the suspension performance.

Zinc oxide has made the product film flexible, firm, impervious to water, so as to prevent gold rust. But should not be mixed with free acid more base material, to produce more rabbit zinc soap, so that the coating is sticky and not easy to brush. Zinc oxide is used for anticorrosive or Marine coatings. It can form dense zinc titanium compounds, reduce the rate of further infiltration of corrosive media, and mainly play the role of rust prevention.

Zinc oxide is an alkaline compound that can react with trace free fatty acids to form zinc soap. It has a tendency to thicken paint, and will dissolve in case of inorganic acid or acetic acid.

Paint grade zinc oxide particle size is small, the surface area is large, has a strong adhesion and hiding power, which improves the effect of paint, paint with zinc oxide in use will eventually form precipitation, has a certain role in shielding ultraviolet light.

Production methods

1. Direct method:

Zinc concentrate is used as raw material, which is reduced to zinc vapor by high temperature oxidation roasting and coal addition, and zinc oxide is obtained by zinc vapor oxidation with hot air. Now the main raw materials are zinc ore, zinc ash and so on. Generally, there are the following kiln structures:

(1) flat kiln. In the process of high temperature oxidation roasting, slag is leaked from the bottom of a cubic kiln which is converted from refractory to construction. Raw material: zinc ore, zinc ash, zinc content is more than 30%. Output: about 2 to 3 tons per day of furnace body 6 square meters. The content is between 85% and 99%. The equipment investment is about 400,000 yuan. Advantages: because it is fired with anthracite, zinc oxide color is good, sulfur root, chlorine root content is low. The raw materials are abundant and the products are widely sold.

(2) rotary kiln. The process of high temperature roasting is in a round iron cylinder with an inclination of about 20 degrees and a length of about 40 meters. The material is fed from the top and the slag is discharged from the bottom. The steam is collected and oxidized to zinc oxide. Raw material: a variety of industrial zinc containing waste residue, generally zinc content of more than 16% can be used, the output of round iron cylinder about a meter of 10 tons of goods per day, the content between 55%-92%, equipment investment of about 600,000 yuan. Advantages: raw material requirements are not high, high recovery rate. High output. Some zinc oxide color yellow, some gray. High content of sulfur and chlorine. Generally used as raw materials for other industries.

(3) fuming furnace. The specific production process is unknown. Raw material: industrial zinc waste residue, generally zinc content of more than 14%, output of 20 tons per day, content in 45-80%. Equipment investment of 1 million yuan. Advantages: high recovery rate, high yield. Zinc oxide is yellowish or gray in color. If the manufacturer has good control, the sulfur and chlorine are not high.

2. The indirect method:

The zinc ingot is melted into the evaporative crucible, heated, gasified, oxidized by air, cooled and captured with a cloth bag to get the finished product. The output is about 5 tons a day. The content of 99.7%, but now also useful zinc slag smelted into zinc block instead of zinc ingot, the production of zinc oxide content in about 99.5. Equipment investment of 400,000 yuan. Advantages: high product content, high yield, easy process control. Zinc oxide is white and yellowish. Good activity. However because raw material is zinc ingot, the price fluctuates along with zinc ingot price change is bigger.

3. Chemical method:

The secondary zinc oxide, ammonia water and ammonium bicarbonate were put into the leaching tank according to the ratio of 1 (effective zinc) ∶8∶1 ~ 1.5 (weight ratio), heated to 50℃ ~ 80℃ for reaction, and the impurities were removed after adjusting the pH value. After 5-8 hours of evaporation, basic zinc carbonate precipitated liquid-solid mixture is obtained. After the decomposed ammonia is absorbed, it is led through the ammonia circulation system to the leaching tank of Step (1) for recycling. After the obtained zinc carbonate is dried by spin-drying, zinc oxide with content of 99.8% is obtained by roasting. Raw material: secondary zinc oxide or other low content zinc oxide produced by rotary kiln or fuming furnace. Output: about 4 tons per day. Equipment investment of 1 million yuan. Advantages: product purity is good, contain lead, cadmium, kun and other impurity less. Because the secondary zinc oxide contains a certain amount of lead, the waste lead slime in the production process can offset part of the production cost. Stable raw materials and market development to master. Because ammonia gas is recycled in the production process, it is also called ammonia process to produce zinc oxide.