High and uncontrolled surface active substances (SAS) concentrations in deinking line process wat... more High and uncontrolled surface active substances (SAS) concentrations in deinking line process waters strongly disturb flotation deinking. Indeed, their adsorption at air/water and ink/water interfaces stabilizes air bubbles and ink particles, reducing ink collection during flotation. In addition, foam stabilization promoted by SAS reduces froth drainage and consequently enhances suspended solids losses. All in all, selectivity of flotation is negatively affected by excessive SAS concentrations. Floating process water with adapted technology, a patented solution, is an efficient way to decrease SAS concentration and thereby recover flotation deinking selectivity. This concept was tested at industrial scale with success. First loop clear filtrates of a deinked pulp line (for newsprint production) were floated. At steady state, this treatment allows a 20% reduction of the SAS concentration in first loop process water. Evaluation of ink removal selectivity at pre-flotation and post-flot...
Biocide programs have become necessary in most fine paper manufacturing circuits, as drastic redu... more Biocide programs have become necessary in most fine paper manufacturing circuits, as drastic reduction of fresh water consumption in the industry enhances microbial development. Depending on their chemical nature, biocides may interfere with typical wet-end chemistry additives and furnish. A reference wet-end chemistry was set (including fixing aid, dry strength aid, sizing agent, and retention system), then biocides were added to the furnish (bleached virgin fibres + mineral filler) prior to handsheet making. Four of the tested biocides (organo-sulfur, dibromonitrilopropionamide, isothiazoline, and glutaraldehyde) were not found to interact with wet-end chemistry. On the other hand, the tested quaternary ammonium salt biocide showed very detrimental effects: it reduced filler retention in the sheet, decreased sheet strength, and destroyed sizing (sheet hydrophobicity).
High and uncontrolled surface active substances (SAS) concentrations in deinking line process wat... more High and uncontrolled surface active substances (SAS) concentrations in deinking line process waters strongly disturb flotation deinking. Indeed, their adsorption at air/water and ink/water interfaces stabilizes air bubbles and ink particles, reducing ink collection during flotation. In addition, foam stabilization promoted by SAS reduces froth drainage and consequently enhances suspended solids losses. All in all, selectivity of flotation is negatively affected by excessive SAS concentrations. Floating process water with adapted technology, a patented solution, is an efficient way to decrease SAS concentration and thereby recover flotation deinking selectivity. This concept was tested at industrial scale with success. First loop clear filtrates of a deinked pulp line (for newsprint production) were floated. At steady state, this treatment allows a 20% reduction of the SAS concentration in first loop process water. Evaluation of ink removal selectivity at pre-flotation and post-flot...
Biocide programs have become necessary in most fine paper manufacturing circuits, as drastic redu... more Biocide programs have become necessary in most fine paper manufacturing circuits, as drastic reduction of fresh water consumption in the industry enhances microbial development. Depending on their chemical nature, biocides may interfere with typical wet-end chemistry additives and furnish. A reference wet-end chemistry was set (including fixing aid, dry strength aid, sizing agent, and retention system), then biocides were added to the furnish (bleached virgin fibres + mineral filler) prior to handsheet making. Four of the tested biocides (organo-sulfur, dibromonitrilopropionamide, isothiazoline, and glutaraldehyde) were not found to interact with wet-end chemistry. On the other hand, the tested quaternary ammonium salt biocide showed very detrimental effects: it reduced filler retention in the sheet, decreased sheet strength, and destroyed sizing (sheet hydrophobicity).
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