摘要：Potential control of soluble aluminium in Al-bearing acidic discharge neutralization by formation of precipitates other than Al(OH)3 was studied. At pH around 5.5, precipitates formed in field and laboratory showed that Al-solids contained sulfate and silicon. Although the soluble aluminium concentration do not match each of the solubility of species of Al-precipitates, the reason that soluble aluminium concentrations were less than solubility of amorphous Al(OH)3 was due to the formation of Al-sulfate. The laboratory experiments of synthetic ARD showed that basaluminite was formed and this was the reason that soluble Al concentration became less than the solubility of amorphous Al(OH)3. The change of sulphur contents in the sludge with pH revealed that more Al-sulfate (basaluminite) was formed at high pH (~8.3). The atomic ratio of Al/OH at different pH values suggested that the sludge formed at neutral pH conditions contained the most proportion of Al(OH)3. The formation of these precipitates provides a possible mechanistic explanation for the decrease of soluble Al concentration in neutralization of ARD.
关键词：Basaluminite;Jurbanite;Amorphous Al(OH)3 solubility;Al-bearing acid rock discharge;Al-precipitates
