Disclosed is a pitch control agent including a (meth)acrylamide-based amphoteric polymer. The (meth)acrylamide-based amphoteric polymer contains 50 mol % or more of (meth)acrylamide, 0.5 to 20 mol % of a diallyldialkylammonium salt; and 0.1 to 14 mol % of an anionic monomer, as copolymerizable monomer components. This pitch control agent is less likely to be affected by a change in a surrounding environment, and therefore can exhibit excellent pitch controllability under various environments in paper production process.

Embodiments are directed to methods for inhibiting contaminants formation during papermaking operation. The method includes preparing an aqueous solution having a pH greater than 7.0 and comprising peroxide; and applying the aqueous solution onto or within one or more of forming wires, press felts and woven through air drying (TAD) belts prior to contacting and transporting a wet paper web to inhibit the formation of wet paper web contaminants onto the surfaces of or within the forming wires, press felts and woven TAD belts.

A method for suppressing sedimentation of suspended substances is a method for suppressing sedimentation of suspended substances in water at the bottom of a tank disposed in a water system in papermaking equipment, comprising a step of blowing an oxygen-containing gas into the water, for stirring and aeration; a step of detecting a change with time in existence states of the suspended substances in the tank by the stirring and the aeration; and a control step of feeding at least one of an oxygen-containing gas and a slime control agent to the tank based on the detection result to suppress the sedimentation of the suspended substances in the tank.

Some embodiments of the present invention relate to a method for reducing the concentration of reactive silica in a first composition comprising adding a first amount of a calcium salt and a second amount of a magnesium salt to the first composition to form a solid silicate composition comprising one or more silicates, wherein the first composition comprises an aqueous solution; and a significant portion of the reactive silica in the first composition is converted to one or more silicate in the solid silicate composition.

The disclosure provides methods and compositions for reducing the viscosity of black liquor. Also provided are methods of inhibiting deposition of scale and methods of processing black liquor. In some embodiments, the compositions include a carboxylate-containing polymer and an inorganic salt. In some embodiments, the compositions include a carboxylate-containing polymer, an inorganic salt, and a surfactant.

Compositions and methods for the removal and prevention of scale in pulp mills in a continuous and real-time process. More particularly the composition includes one or more chelating ligands, one or more copolymers, and one or more surfactants. The scale removing composition is added to the black liquor stream in pulp and paper processes to remove scaling, such as scaling from calcium carbonate, from surfaces in contact with the black liquor stream, such as in digestors and evaporators.