Treatment of tailings pond sludge
AssigneeSuncor, Inc.
InventorRaymond N. Yong
Life of this patent
Estimating the term…
Abstract
A tailings pond sludge layer of high density and strength is obtained by treating the sludge with an additive selected from a specific family of hydrolized starch additives which impart improved permeability and shear strength characteristics to the sludge. Thereafter, the sludge is mixed with sand which adds self-weight whereby further dewatering of the sludge sand mixture is accomplished. Unlike untreated sludges or sludges treated with other known additives or flocculants, sludge treated with the aforementioned hydrolyzed starch additives is able to support the sand.
Claims9
In a tailings pond system for receiving fines-containing aqueous effluent from an industrial process, the method of obtaining a more thoroughly dewatered sludge layer in the tailings pond by sand surcharging comprising the steps of:
- (A) treating the effluent with at least 37 ppm of a hydrolyzed starch additive, which additive is obtained by the aqueous hydrolysis of the starch in the presence of one or more insoluble metal salts formed in situ;
- (B) mixing the treated effluent with an effective surcharging amount of sand;
- and
- (C) discharging the treated effluent/sand mixture into the tailings pond;
- whereby the treated effluent/sand mixture settles into a sludge layer from which water migrates upwardly.
In a man-made or naturally-occurring fines-containing body of water, the method of obtaining a more thoroughly dewatered sludge layer in the body of water comprising the steps of;
- (A) treating the sludge with at least 37 ppm of hydrolyzed starch additive, which additive is obtained by the aqueous hydrolysis of the starch in the presence of one or more insoluble metal salts formed in situ;
- and
- (B) mixing the treated sludge with about three times the weight of said sludge mineral solids of sand;
- whereby the hydrolyzed starch additive imparts sufficient strength and permeability to the sludge for supporting the sand and promoting migration of the water, and the sand adds self-weight to the sludge layer such that water within the sludge layer migrates upwardly out of the sludge layer.
Dependencies are inferred from the claim text.