Dry, stackable tailings and methods for producing the same
View Patent ↗Methods for preparing solvent-dry, stackable tailings. The methods may include a primary leaching or extraction process that separates most of the bitumen from a material comprising bitumen and produces first solvent-wet tailings. The first solvent-wet tailings are washed with a second solvent that removes the first solvent from the tailings. Second solvent remaining in the tailings is removed to thereby produce solvent-dry, stackable tailings.
1. A method comprising:
providing material comprising bitumen having a bitumen by volume content;
mixing the material comprising bitumen with a first solvent at a rate of from 0.5 to 3.0 times the amount of bitumen by volume content of the material comprising bitumen and forming a first mixture, wherein the first mixture comprises a bitumen-enriched solvent phase;
separating a first portion of the bitumen-enriched solvent phase from the first mixture and forming a bitumen-depleted tailings phase; and
adding a second solvent to the bitumen-depleted tailings phase at a rate of from 0.5 to 1 times the amount of bitumen by volume content of the material comprising bitumen and separating a second portion of the bitumen-enriched solvent phase from the bitumen-depleted tailings phase;
wherein the first solvent is a different type of solvent than the second solvent.
2. The method as recited in claim 1 , wherein the first solvent comprises light aromatic solvent.
3. The method as recited in claim 2 , wherein the light aromatic solvent comprises kerosene, diesel, gas oil, naphtha, benzene, toluene, an aromatic alcohol, derivatives thereof, or combinations thereof.
4. The method as recited in claim 2 , wherein the second solvent comprises a volatile hydrocarbon solvent.
5. The method as recited in claim 4 , wherein the volatile hydrocarbon solvent comprises cyclo- or iso-paraffin having between 3 and 9 carbons, derivatives thereof, or combinations thereof.
6. The method as recited in claim 4 , wherein the second solvent is liquefied petroleum gas.
7. The method as recited in claim 2 , further comprising:
upgrading a bitumen component of the bitumen-enriched solvent phase.
8. The method as recited in claim 2 , wherein the material comprising bitumen comprises tar sands.
9. The method as recited in claim 2 , further comprising:
mixing the bitumen-depleted tailings phase with an additional quantity of first solvent and separating residual bitumen-enriched solvent phase from the bitumen-depleted tailings phase prior to adding a second solvent to the bitumen-depleted tailings phase.
10. The method as recited in claim 9 , wherein the first solvent and the additional quantity of first solvent are the same solvent.
11. The method as recited in claim 9 , wherein the first solvent and the additional quantity of first solvent are different types of light aromatic solvent.
12. The method as recited in claim 2 , wherein the material comprising bitumen is mixed with the first solvent at a rate of from 0.6 to 2.0 times the amount of bitumen by volume content of the material comprising bitumen.
13. The method as recited in claim 2 , wherein the material comprising bitumen is mixed with the first solvent at a rate of from 0.75 to 1.0 times the amount of bitumen by volume content of the material comprising bitumen.