Dewatering aqueous suspensions of organic solids

Claim 1

IN A PROCESS FOR DEWATERING A LIQUID, AQUEOUS SUSPENSION OF PREDOMINATELY ORGANIC, HYDROPHILIC SOLIDS NOT SUSCEPTIBLE OF CONDITIONING FOR DEWATERING WITH AN ANIONIC ORGANIC POLYMER AS THE SOLE TREATING AGENT, WHICH SOLIDS ARE IN AN AGGLOMERATED CONDITION AND AT A CONCENTRATION WHEREBY THE SOLIDS ARE ESSENTIALLY NON-FREE SETTLING, WHICH PROCESS COMPRISES ADDING TO THE SUSPENSION WITH MIXING A WATER-SOLUBLE, CATIONIC, NITROGENOUS ORGANIC POLYMER, SAID POOLYMER BEING EMPLOYED IN AN AMOUNT SUFFICIENT TO PROMOTE DEWATERING OF THE SUSPENSION; THE IMPROVEMENT WHICH CONSISTS IN ADDING TO THE SUSPENSION PRIOR TO THE ADDITION OF THE NITROGENOUS ORGANIC POLYMER, AND WITH INTERVENING MIXING, A WATER-SOLUBLE, HIGH MOLECULAR WEIGHT, ANIONIC ORGANIC POLYMER CHARACTERIZED BY A MOLECULAR WEIGHT OF AT LEAST 0.5 MILLION AND AS HAVING A POLYALKANE BACKBONE WITH A PLURALITY OF IONIC SUBSTITUENT GROUPS SELECTED FROM THE GROUP CONSISTING OF CARBOXYLIC AND SULFONIC ACID GROUPS AND ALKALI METAL SALTS OF THE ACID GROUPS; THE TOTAL WATER OF DILUTION ADDED WITH THE POLYMERS BEING MAINTAINED WITHIN THE RANGE FROM ABOUT 0.01(S) TO ABOUT 1.0(S) VOLUMES OF WATER PER VOLUME OF LIQUID AQUEOUS SUSPENSION, WHEREIN S EQUALS THE PARTS OF SOLIDS, ON A DRY BASIS, PER 100 PARTS OF AQUEOUS SUSPENSION AND SAID ANIONIC ORGANIC POLYMER BEING ADDED TO THE AQUEOUS SUSPENSION IN A SMALL AMOUNT, RELATIVE TO THE AMOUNT OF NITROGENOUS ORGANIC POLYMER USED, SUCH AMOUNT OF ANIONIC POLYMER BEING EFFECTIVE TO ENHANCE THE DEWATERING RATE OF THE TREATED AQUEOUS SUSPENSION.