US 2020/0002197 A1 · ENHANCED FLOCCULATION OF INTRACTABLE SLURRIES USING SILICATE IONS

Abstract

Methods are provided for treating intimately dispersed mixtures of water, bitumen, and fine clay particles, such as oil sands mature fine tailings (MFT). Select methods use dissolved silicate ions and a base (alkali), optionally in combination with a biopolymer, to flocculate a slurry. A mixing regime is disclosed involving the addition to MFT of silicate ions in solution and alkali, to initiate aggregation/destabilization of clay particles. Methods are exemplified that provide distinct sediment layers in conjunction with the release of residual bitumen (for example 40-50% of the initial bitumen content). In these exemplified embodiments, a densely packed bottom layer containing ˜75 wt. % solids showed high yield stress values (3.5-5.5 kPa) and entrapped little residual bitumen (0.2-0.3 wt. %). The methods accordingly segregate a material suitable for reclamation.

Claims34

Dependent claims

A process for treating a slurry comprising an intimately dispersed mixture of water, bitumen, and fine clay particles, having a slurry solids content of 20-50%, a pH of 7 to 8.5, an aluminate concentration of less than 85 mg/L and a sulfate concentration of less than 110 mg/L the process comprising:

adding a source of silicate H3SiO4− ions to the slurry to provide a silicate-treated slurry having a silicate ion dosage of about 350-20,000 ppm (or 350-20,000 g silicate ion per metric ton of dry tailings);
optionally adding a biopolymer co-agent in the form of polysaccharides in the dosage of 500-2000 ppm (or 500-2000 g of agent per metric ton of dry tailings);
adding an alkali to the silicate-treated slurry to raise the pH to provide a basic silicate-treated slurry having a pH of from about 9 to about 12, or about 10;
and,
allowing the basic silicate-treated slurry to separate into a plurality of layers having distinct densities, wherein a bottom layer comprises packed clay particles.

2 more elements

Dependencies are inferred from the claim text.

Enhanced flocculation of intractable slurries using silicate ions

Life of this patent

Enhanced flocculation of intractable slurries using silicate ions

Life of this patent

Abstract

Claims34