A defoamer or anti-foam formulation and a process for preparing the same. The process includes in a first step, preparing branched organopolysiloxanes (A) by irradiating organopolysiloxanes (X) of the formula (1)
R.sup.1.sub.3-a(R.sup.2O).sub.aSi[OSiR.sup.3.sub.2].sub.nOSi(OR.sup.2).sub.aR.sup.1.sub.3-a (1).
Where with high-energy radiation, the viscosity of the organopolysiloxanes (A) is at least 40% higher than the viscosity of the organopolysiloxanes (X). In a second step, the branched organopolysiloxanes (A) are treated with a filler (B) which is selected from precipitated and/or fumed silicas, and organopolysiloxane resins (C).

A method for processing black liquor includes operations of: (A1) ultrafiltering the black liquor; (A2) mixing the ultrafiltration concentrate with carbon dioxide and/or sulfuric acid to precipitate lignin in the ultrafiltration concentrate, and obtaining a first inorganic aqueous solution; (A3) mixing the first inorganic aqueous solution with the ultrafiltration permeate to obtain a mixture, and nanofiltering the mixture; (A4) mixing the nanofiltration concentrate with carbon dioxide and/or sulfuric acid to precipitate lignin in the nanofiltration concentrate, and obtaining a second inorganic aqueous solution; (A5) performing a first electrodialysis treatment or reverse osmosis treatment on the second inorganic aqueous solution, and obtaining a remaining inorganic aqueous solution; (A6) mixing the remaining inorganic aqueous solution with the lignin obtained from operation (A2) and/or operation (A4) to obtain a first fuel liquid; and (A7) processing the first fuel liquid to produce sodium sulfide, sodium carbonate, carbon dioxide, and steam.

A foam control agent and method of controlling foam for paper or pulp production by use of a foam control agent, wherein the agent comprises at least a branched alcohol.