초록

A method for dewatering clay slimes comprised of treating the slimes with a fly ash coated with a silane coupling reagent to which is bonded a polyacrylamide flocculant.

대표청구항 ▼

A method for dewatering clay slimes diluted to less than 3% solid content comprising the following steps: a. Hydrating fly ash for at least 7 days; b. Reacting the hydrated fly ash with a silane coupling agent to couple the silane to the ash; c. Polymerizing the fly ash with an acrylamide monomer to

A method for dewatering clay slimes diluted to less than 3% solid content comprising the following steps: a. Hydrating fly ash for at least 7 days; b. Reacting the hydrated fly ash with a silane coupling agent to couple the silane to the ash; c. Polymerizing the fly ash with an acrylamide monomer to form an acrylamide flocculant chemically bonded to said fly ash through said silane; d. adding an effective amount of the polymerized fly ash to flocculate said clay slime; e. Allowing the flocculated slime to settle; and f. Recovering the supernatant water. A method according to claim 1 in which the clay slime is the waste product of a phosphate benefication process. A method according to claim 9 comprising the following steps: a. Hydrating fly ash for 7-21 days; b. Charging the hydrated fly ash into a reactor containing 4 milliliters of water per gram of fly ash; c. Maintaining a pH 6 by the addition of concentrated sulfuric acid; d. Adding sufficient triacetoxyvinylsilane to produce a 0.075 to 0.05% by volume silane solution concentration; e. Stirring the solution for 30 minutes; f. Adding additional water; g. Purging the contents of the reactor with nitrogen gas while adding 47.5 parts acrylamide monomer to 949.8 parts water and 0.144% by monomer weight of a stoichiometric amount of ammonium persulfate plus sodium sulfite; h. Heating the mixture to 65°C. to polymerize the monomers and react with the fly ash; i. Diluting the phosphate slime with deionized water to obtain a less than 3% solids concentration; j. Charging the polymerized ash into a flow of diluted slime to flocculate slime particles; k. Charging the mixture of slime and flocs into a mechanical thickeners; l. Allowing the solids to consolidate and recovering the supernatant water; m. Transporting the consolidated slimes to settling ponds; and n. Adding sand to the settling pond to facilitate settlement of the slime.