Effect of zinc oxide quality on zinc stearate

The zinc oxide production process is divided into:

        Direct method:

        Using zinc concentrate as raw material, after high temperature oxidation roasting to remove impurities such as lead, cadmium and sulfur, it is combined with reduced coal and pressed into a dough, and then reduced in the furnace at high temperature to volatilize the zinc vapor and CO2 in the furnace gas. The introduced air is directly oxidized to zinc oxide. Zinc oxide produced by the direct method usually has needle-like or rod-like crystals, and the particles are coarse. In addition to the quality of the process and the quality of the zinc concentrate, the quality of the product is also related to the quality of the reduced coal, which is directly contaminated by the combustion products of the reduced coal.

        Indirect method:

        Also known as the French law. The metal zinc is used as a raw material, and after melting, the evaporation furnace is introduced, and then the zinc vapor is burned into zinc oxide under certain oxidation conditions. Indirect method products are not polluted by fuel combustion products like the direct method, so the purity is high, the content of heavy metal impurities is low, the whiteness of the product is more than 86%, and the direct whiteness is 83%. Fine, dispersible, usually spheroidized. This method has the characteristics of continuous and stable production, low energy consumption and high product quality. Indirect method for producing zinc oxide, because zinc vapor is not contaminated by fuel combustion products, so the product has high purity and white color (whiteness is above 86%).

        Wet method:

　　The wet process for producing zinc oxide is based on the zinc-containing material, and firstly, a zinc-containing solution is prepared, and then a zinc compound (such as zinc carbonate) which is easily converted into zinc oxide is precipitated from the purified zinc-containing solution, and zinc is precipitated. The compound precipitate is calcined to obtain zinc oxide. This method produces active zinc oxide having a fine particle size and a large specific surface area (more than 30 m 2 /g). Compared with the three processes, each process of zinc oxide has its own characteristics.

　　For the production of zinc stearate, we generally use zinc oxide produced by indirect method. The indirect method is divided into zinc slag and zinc ingot (other metal contents are different). Compared with the three processes, the indirect method of zinc oxide has high whiteness and purity. High, moderate activity, more suitable for the production of zinc stearate.

        The basic indicators of zinc oxide on the production of zinc stearate:

        Whiteness: There are many factors affecting the color of zinc stearate. Among them, the whiteness of zinc oxide, the higher the whiteness, the whiter the color of zinc stearate produced.

        Other metal content: The content of other metals contained in zinc oxide directly affects the free acid index, transparency, and infusity of zinc stearate. Therefore, zinc oxide which produces zinc stearate requires other metal content of less than 20 PPM.

        Zinc content: Zinc content affects the zinc stearate free acid index. Zinc oxide with too low zinc content will increase the cost of producing zinc stearate.

        Activity: The activity of zinc oxide affects the rate of production of zinc stearate. Too low activity results in slow reaction, long heating time, poor efficiency and yellowing of the color. Excessive activity can lead to violent reactions that are difficult to control. So the reason is not to use wet zinc oxide.

        Fineness: The fineness of zinc oxide has an effect on the reaction of zinc stearate. The finer the fineness, the faster the reaction speed, and the slower the reverse, the fineness should be in a suitable range. The reaction is too fast to control, too slow. Increased costs.

        Although the amount of zinc oxide used in the zinc stearate industry is relatively small, the development prospects and development trends of zinc stearate cannot be underestimated. Regardless of whether it is an environmentally friendly green composite stabilizer or a coating, its advantages are slowly being discovered. I believe that in the near future, the application of zinc oxide in the zinc stearate industry will be greatly improved.