New chemicals, based on the synergistic effect between inorganic polyaluminium salts and organic cationic polyelectrolytes, have been tested previously at lab scale and the most efficient product has been selected for an industrial trial for a dissolved air flotation unit of a paper mill based on 100% recovered paper (Part 1 of this work). A polyaluminium nitrate sulphate salt combined with a quaternary polyamine has been evaluated in a long-term industrial trial for assessing its potential

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... fits. Results indicate that this new chemical is able to improve the removal of contaminants by dissolved air flotation, especially when the contamination load of the waters is high, allowing a further closure of the water circuits.