| In this thesis, two kinds of poly aluminum sulfate crystallization were successfully prepared under the guidance of the phase diagram. They are [H3O]w{Al3(OH)6(SO4)2]n and A12(OH)4SO4·5H2O. The crystal structure of [H3O]n[Al3(OH)6(SO4)2]n has been analyzed with the Rietveld method. The structure of [H3O]n[Al3(OH)6(SO4)2]n was continual six ring and layer structure in which the sulfate participates. A12(OH)4SO4·5H2O was characterized by chemical analysis and XRD, the result demonstrated that A12(OH)4SO4·5H2O is a new species of poly aluminum sulfate. The composition and structure of A12(OH)4SO4·5H2O were different from [Al2(OH)2(H2O)8(SO4)2·2H2O]as reported before, which indicated that a new structure of poly aluminum speciation may be obtained.In this thesis, the solid-liquid equilibrium diagram of AlC13—Al2O3—H2O at50℃was drawn by means of wet dregs based on a lot of chemical-analysis data, using aluminum powder to adjust the basicity of the solution of aluminum chloride. And under the guidance of the phase diagram, the optimal crystalline conditions for the formation of pure compounds were determined and two kinds of pure hydrated polyaluminum chloride crystals were prepared. They were Al9Cl6(OH)21·18H2O and Al5Cl3(OH)12·7.5H2O with the purity of92.7%and99.2%respectively. And two poly aluminum species were characterized by chemical analysis, powder XRD phase analysis, Infrared spectroscopy and thermal analysis.In addition, one kind of crystal hydrated polyaluminum bromide(PAB) has been obtained by the same method. The result of XRD analysis indicated it was l5Br3(OH)12·6H2O. The result of chemical analysis showed that the purity have improved8.82%than that our group preparated before... |
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