Study on ultrafine active zinc oxide by ammonia method

According to the National Collaborative Group survey zinc salts, zinc oxide overseas industrial development is more mature, in recent years, in a relatively stable state, the consumption of zinc oxide in 1999, the United States, Japan, Western Europe, a total of 5.823 million tons, the actual output of a total of 4.665 million tons. In sharp contrast with foreign countries, the rapid development of China's automobile industry in recent years, coupled with the rapid development of China's coating industry, has made China's demand for zinc oxide increasing year by year. It is estimated that by 2005 , China's zinc oxide will continue to develop at a rate of 6 to 8 %. According to the 2000 industry survey of the National Zinc Salt Collaboration Group , there are currently 96 zinc oxide production enterprises in China . In 2000 , the actual output of zinc oxide was 306,300 tons.

The zinc oxide production process at home and abroad is mainly based on direct and indirect methods, and a small amount is produced by wet process. Most of the zinc oxide produced by the wet process is a sulfuric acid process. A large number of by-products are difficult to recycle, and environmental protection problems are difficult to solve. The direct-process zinc oxide process directly produces zinc oxide products by oxidation-reduction of raw materials containing zinc oxide. This law limits the raw material, the quality is not high, low price; indirect process for the production of zinc oxide to zinc metal smelting purified as raw materials, melting, vaporization, oxidizing the zinc oxide produced. The method has a higher production cost. The ammonia method wet process is the development direction of the domestic zinc oxide production process. And its products are easy to achieve multiple varieties, multiple specifications. Can be widely used in rubber, paint, ceramics, magnetic materials and other fields.

Nanjing lead-zinc-silver mining company by the Guangxi Institute of Metallurgy collaborative research to the successful development of ultra-fine zinc oxide ammonia new technology and products. In 2001 , the “Ammonia Process Superfine Zinc Oxide New Process and Its Products” was appraised by the Jiangsu Science and Technology Department and identified as a high-tech product by the Nanjing Economic Commission. In recent years, several units in China have been studying similar processes, and our current level is at an advanced level among peers.

The new process of ultra-fine zinc oxide by ammonia method overcomes the shortcomings that the environmental protection problem of sulfuric acid process is difficult to solve. It uses zinc oxide baking sand as raw material, desulfurization, washing and leaching, except copper , lead, iron and manganese ; deep static, Hydrolyzed, distilled ammonia, dried, calcined to produce ultra-fine active zinc oxide products.

Advantages of the new process of ammonia superfine zinc oxide compared to existing zinc oxide production processes:

1. Low production costs. The direct method zinc oxide and the indirect method zinc oxide are different depending on the materials used. Therefore, the production cost is not the same. The former has a significantly lower production cost than the latter. In the direct method, the ammonia method and the acid method have similar production costs, and the ammonia method can be used in the raw materials in combination with low-grade zinc oxide, zinc ash, smithsonite, and zinc dust to make the production cost lower.

2. The product has high activity. The principle of zinc oxide production is different, and the crystal form of the product is different. Therefore, the chemical activity is very different. The ultrafine zinc oxide produced by the ammonia process has a fine particle size, a large specific surface area, and a crystal form which is porous. Therefore, it has the characteristics of high chemical activity.

3. The product has high purity. Since the ammonia method uses various purification measures in production, the impurity metal content is minimized. At the same time, the problem of residual sulfate in the acid process product is also avoided.

4. There are many varieties of products. The indirect method is limited by the process, and there is only one product, indirect zinc oxide. The ammonia process produces different properties of zinc oxide and zinc salt products through a fine-tuning process. To meet the different needs of users. Adapt to the broad needs of the market.

5. Wide range of raw materials. Ammonia process materials have the widest adaptability. Zinc calcine, low-grade zinc oxide, zinc ash, and sphalerite can be used as raw materials for the ammonia process. Today, mineral resources are becoming increasingly scarce, which is a big advantage.

6. Environmental protection is guaranteed. The design idea of ​​the ammonia process is the closed cycle of water and ammonia. There is no pollution problem with general wet process water production.

In addition, we can produce zinc oxide with a particle size of 40 to 60 nm by adjusting certain process parameters and process steps .