Alumino complexes phosphate

We have noted earlier that aluminium is unusual in forming alumino-phosphate complexes in phosphoric acid solution which may be of a polymeric nature. Bearing in mind the analogies between aluminium phosphate and silica structures, it may well be that during cement formation an aluminium phosphate hydrogel is formed. Its character may be analogous to that of silica gel, where a structure is built up by the... 

Both humic acids and fulvic acids have a strong affinity for particulate and crystalline substances possessing oxygen atoms at their surfaces and they have been reported to bring about the dissolution of iron phosphate, calcium phosphate (61), uranium dioxide (65), hydrated magnesium alumino-silicates (66) and limonite, a complex mixture of hydrated ferric oxides (67). 

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