| PATENT CLAIMS |
Process for pressure dewatering an aq. mineral suspension having mineral solids > 150 g/l comprising mixing into the suspension water-solu
ble anionic bridging polymeric flocculant having intrinsic visc. > 5 dl/g & water-soluble cationic polymeric flocculant, wherein the anionic flocculant is in the form of a water-soluble alkali metal salt & the cationic flocculant is in the form of a water-soluble quat. ammonium salt, allowing the suspension to flocculate & dewatering the flocculated suspension under pressure
Wherein the anionic & cationic flocculants are mixed into the suspension by blending 1 part by wt. of cationic flocculant with 2-20 parts by wt. of the anionic flocculant & sufficient water to give a polymer concn < 5% by wt. & under conditions whereby counterionic precipitation occurs & thereby forming an aq. compn in which all the anionic polymer which is not precipitated by the cationic polymer is in soln & wherein the ppcc has formed around the dissolving cationic polymer, & mixing this aq compn into the suspension
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