Ultrafine Aluminum Hydroxide Preparation Technology

Up to now, enterprises in the industry that produce ultrafine aluminum hydroxide on a large scale mainly adopt the seed separation process to produce ultrafine aluminum hydroxide. Seed separation process refers to the production process of crystallizing ultrafine aluminum hydroxide from sodium aluminate solution by adding active crystal seeds in sodium aluminate solution and relying on the drive of supersaturation. Among them, the preparation of active crystal seeds is the key link in the seeding process.

The mainstream seed separation process technology for large-scale production is mainly aluminum sulfate neutralization of crystal seed method, sodium bicarbonate neutralization of crystal seed method, and mechanical grinding of crystal seed decomposition method. Globally, the U.S. Qiu Bo, Germany Nabotai, Japan Sumitomo, Showa Denko, etc. are mainly used in aluminum sulfate neutralization and mechanical grinding of crystal seed decomposition method, its production technology and product quality are among the world's leading level. Shandong New Material is the earliest enterprise in China to produce ultrafine aluminum hydroxide flame retardant by mechanical grinding and crystal seed decomposition method. Zhongzhou New Material is the earliest enterprise in China to produce ultrafine aluminum hydroxide flame retardant by adopting the method of neutralizing crystal seeds with aluminum sulfate.

Some enterprises in the industry prepare ultrafine aluminum hydroxide powder by physical grinding method. Compared with the seed separation process, the scale production of physical grinding method has shortcomings such as coarse particle size, different sizes, and many crystal defects, therefore, the technical route of physical grinding method is difficult for large-scale production, and it is subject to greater limitations in the scale use of downstream high-standard products.

(2) The main technical development direction of ultrafine aluminum hydroxide flame retardants

In polymer materials, increase the filling amount of ultrafine aluminum hydroxide to help enhance the flame retardant properties of composite materials; but aluminum hydroxide is a typical polar inorganic materials, and organic polymers, especially non-polar polyolefin compatibility, interfacial bonding force is small, the increase in the filling amount will lead to a decline in the processing performance and mechanical properties of the composite material.

The development of ultrafine aluminum hydroxide with "high filler, high flame retardant, high mechanical properties" is the industry's mainstream enterprise technology research and development focus and technology development direction. At the same time, how to achieve "high filler, high flame retardant, high mechanical properties" characteristics of ultrafine aluminum hydroxide of large quantities of industrial production, to maintain the stability of batch to batch and cost-controllable is the mainstream enterprises in the industry urgently need to solve the problem.