| Based on the preivous researches on polyaluminum chloride flocculant, in order to resolve the confusion regarding the actual dominant aluminum species in polyaluminum chloride, two series of respresentative polyaluminum chloride were produced by means of two kinds of preparation methods: one was to add sodium hydroxide solution into the AlCl3 solution to prepare PAC coagulant, the other was to add calcium aluminate powder into hydrochloric acid sulution to prepare CaPAC. Meanwhile, their distribution features, their flocculation performance and coagulation mechanism were described, tested and discussed respectively. On the one hand, the innovated research paved the way for unifying the present argument on aluminum speciation. And on the other hand, the study conclusions provided the scientific basis for a further study on the applied theory of CaPAC.The main research and conclusions were as follows.1. Introducing the method of two-phase for producing Polyaluminium Chloride, by using bauxite and calcium aluminate powder, determining the optimum technological conditions for the first phase: the appropriate calcining temperature was about 650℃, the duration time for calcining were 1h, the temperature for acid dissolving was 85-95℃, the concentration for the hydrochloric acid was 20%, the reaction time for acid dissolving was lh. During the second phase for producing polyaluminum, getting different bascity polyaluminum by adding different amount of aluminium acid calcium powder. The experimental results of removal turbidity showed that the new made polyaluminum had a good flocculation property.2. The Aluminum species distribution of PAC and CaPAC in aqueous solution were characterized and compared using the method of Al-Ferron timed complexation spectroscopy. The results showed that more amount of Alc was easily synthesized by the one-step method of dissolving the calcium aluminate with the hydrochloric acid, but Alb...
|
PDF Full Text Request