CHARACTERISTICS OF SPECIES DISTRIBUTION AND TRANSFORMATION OF POLYMERIC ALUMINUM
聚合铝形态分布特征及转化规律

The hydrolysis-polymerization-precipitation processes of Al(III) were studied by various experimental methods: pH titration, acid depolymeri-zation, timed complex-colorimetric procedure with Ferron-Phenanthroline reagents, ultrafiltration, X-ray diffraction spectrum and infrared absorption spectrum. The results showed that the Al(III) species transformed during the hydrolysis polymerization-processes according to the B= (OH/A1), pH and other factors. By their structure, the species can be divided into three categories of sol-precipitates(Alc), monomeric(Ala) and polymeric(Alb), and the latter may be further divided into three kinds as linear low polymers (Alb1), linear high polymers(Alb2) and high polymers with ring structure (Alb3). The apparent molecular weight graded by ultrafiltration for polymeric species was about 1,000-50,000 and the most of them failed into a range around 10,000. A scheme for chemical speciation model of A1(III)-solution was suggested.