Characteristics Of Polyaluminum Chloride Prepared By Baking Process

As a sort of abroad applied Inorganic Polymer Flocculation (IPF)-Poly Aluminum Chloride (PAC), one importance tache of deciding its ability to industrialization cosmically is making process. PAC is made by partial hydrolysis of acid aluminum chloride solution using a specific reactor. Much attention has been paid to PAC in recent years because of its higher efficiency and relatively low costs. Fluid methods of preparing PAC have been well-rounded. But, there are many limits: complex process, high energy cost, high impurity, etc. Baking process has been had a small number of examples of industrial production. But there are so few reports of its basic research. Particularly on the reports of production influence factors, stability, morphological distribution, flocculation characteristics and mechanism of flocculation of the solid-state PAC by direct thermal decomposition method. And that impacts to the development to be the low power consumption, less pollution, high quality products. Thus, the development of new highly efficient production of inorganic polymer flocculants PAC so as to improve the quality, thereby enhancing coagulation ability is important significance.Base on a great lot reading of literature and the formers'studies, this thesis introduced a new method to make PAC. Made the research scheme first, then had a careful research on characteristics of PAC by baking process. Morphological distribution of PAC was measured using timed colorimetric speciation techniques as the ferron test. Crystal type and appearance of PAC was studied by scanning electron microscope (SEM), Al₁₃ was detected by ²⁷Al-NMR, and remained Al was tested using AAS. And the flocculating efficiency of PAC was also preliminarily examined by jar test. Through the research, conclusions were as follow:1. PAC was prepared with AlCl3·6H2O as raw material. The optimal preparing method was obtained using orthogonal design: baking temperature 290℃; baking time 30min; maturation time 24h; liquids laying aside time 12h. It was propitious to make PAC which was high efficiency if use the proper reaction condition.2. Effect of preparing conditions on PAC products: baking temperature and baking time had great influence on Al2O3%, basic ratio, morphological distribution and flocculating efficiency of PAC; maturation time and liquids stabilizing time had less influence on these capabilities.3. Crystal type and appearance of PAC was studied by SEM: photo of self-made PAC showed that some crystal granule out of order end surface congregated into branches along the straight level. It was similar to the photo of industrial PAC and according with some reported crystal type and appearance photos of PAC. Characterization of PAC–Al13 by 27Al–NMR spectrum showed: PAC made in this way contained Al13 species. Its form mechanism was inclined to 6-central continuous mode.4. Characteristics of polyaluminum chloride prepared by baking process was stability after leaving for half a year.5. The mechanism of coagulation was different between self-made PAC and industrial PAC. The capacity of self-made PAC was better than the industrial PAC.