CA1129800A - Solvent extraction of bituminous sand - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

SOLVENT EXTRACTION OF BITUMINOUS SAND

Hydrocarbons are recovered from bituminous sand by extraction with a solvent containing a ketone, preferably also con-taining acetone. The extraction may either be performed in situ in a bituminous sand deposit or may be performed using mined tar sand. A liquid hydrocarbon component may also be included in the solvent.

Description

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01 3ACKGROUND OF THE INVE~ITION
_ 02 This invention relates to a method for extracting hydro-03 carbon values from bituminous sand.
04 Lar~e deposits of bituminous sand, also called tar sand 05 or oil sand, are found at various locations, notably in the Atha-06 basca region of Canada. The hydrocarbon values obtained frorn bitu-07 minous sand deposits can be ~sed as a supplement or substitute for 08 increasingly scarce petroleum resources. Some bituminous sand 09 deposits are amenable to exploitation by mining and surface proces-sing to recover the bitumen. Other deposits are more susceptible 11 to sub-surface, or _ situ, treatment to recover the bitumen, 12 since the overburden of waste materials is too large to remove 13 economically.
14 -Most prominent among the surface processing techniques previously proposed has been the aqueous froth flotation method;
16 however, solvent extraction of the bitu~inous sand using organic 17 solvents has also been proposed. The commonly proposed solvents 18 are hydrocarbons and hydrocarbon fractions, such as gasoline, 19 naphtha, or gas oil.
U.S. Patent No. 2,453,060 discloses a process wherein 21 bituminous sand is first treated with water, then contacted with a 22 secondary solvent which may be "non-hydrocarbons, such as organic 23 oxygen and sulfur compounds including alcohols, ketones, mercap-24 tans, sulfides, thiophenes, and the like," and finally the bitu-minous sand and solvent are separated from the water as a froth.
26 U.S. Patent No. 3,052,620 discloses the treatment of 27 residual oil shale with water and acetone.
28 U.S. Patent No. 3,475,318 shows the use of a moving bed 29 system in which the tar sand is moved using a belt which acts as a filter for the solvent/bitumen liquid.
31 U.S. Patent No. 3r644~194 discloses a process for 32 removing bitumen from bituminous sand using a water-external 33 _~_ 01 micellar dispersion which contains hydrocarbons, surf~ctant, 02 aqueous medium and, optionally, cosurfactant and/or electrolite.
03 ~he solvent, accordin~ to the patent, may include 1~50 percent 04 hydrocarbon, 40-95 percent aqueous medium, at least about 4 05 percent surfactant, 0.01 to 20 percent or more Oe cosurfactant, 06 and about 0.001 to about 5.0 percent electrolite. The hydro-07 carbons include~ in the solvent can be crude oil, partially 08 refined fractions of crude oil or refined fractions of crude oil.
09 Also suggested are side-cuts, crude oil column overheads, gas oils, kerosenes, heavy naphthas, straight-run gasoline, liquefied ll petroleum gases, etc. Also, synthesized hydrocarbons are stated 12 to be useful. The surfactants sug~ested are of conventional type 13 and are disclosed at length in the patent. The useEul cosur-14 f~ctants are said to have the property of having limited water lS solubility of about 0.01 to 20.0 percent at a~bient temperature.
16 Specific examples listed in the patent o~ cosurfactants include 17 alcohols, amino compounds, esters, aldehydes, ketones, and lilce 18 materials containing rom 1 to about 20 or nore carbon atoms, and l9 more preferably about 3 to about 16 carbon atoms. Alcohols are particularly stressed.
21 U.S. Patent tlo. 3,941,679 discloses the use of solvent 22 extraction with trichlorofluoromethanes, either ln situ in a 23 deposit of the hydrocarbonaceous mineral or by solvent extraction 24 subsequent to Inining of the hydrocarbonaceous material. In the in situ treatment, the liquid CC13F is oumped into the fractured 26 deposit of ~ydrocarbonaceous material and the resulting material 27 is pumped fro~ the deposit. The solvent is then recovered. The 28 method disclosed in this patent appears to be directed prinarily 29 to extraction of kerogen from oil shale.
U.S. Patent ~o. 4,0d6,668 describes the extraction of 31 hydrocarbons froln tar sand using a light naphtha/~ethanol solvent 32 syskeln. This is said to result in rapid decrepitation of the tar 01 sand a~gregatQ and separation of organic matter into three ohases.
02 The most ;3esirable, non-polar organic materials are recovered Lrorn 03 the light naphtha phase; more polar-soluble constituents are 04 recovered from the methanol phase; and less desirable asphaltenes 05 separate as a precipitate.

07 The present invention pertains to a method for separat-08 ing a hydrocarbonaceous component such as bitumen from a mixture 09 including a major proportion of a solid inorganic component, such as sand, and a minor proportion of the bitumen, the process 11 comprising: forminq a liquid phase including said hydrocarbon-12 aceous component and a liquid solvent by contacting the liquid 13 solvent with the mixture, the solvent comprising at least one 14 ketone, preferably including acetone, and particularly preferably containing acetone and 2-butanone, and having from 0.1 to 1.0 16 volume of 2-butanone per volume of acetone therein; and separating 17 at least a portion of the liauid phase from at least a fraction of 18 the solid inorganic component. The present method is particularly 19 suitable for extraction of bitumen from bituminous sand. In addition to the ketone, and preferably the acetone and 2-butanone, 21 t~e solvent employed in the process preferably includes from 0.1 22 to 3.0 volumes of a hydrocarbon component for eah volume o 23 ketone ~or acetone if used) in the solvent. Particularly suitable 24 hydrocarbons include benzene and alkylaromatic hydrocarbons or hydrocarbon fractions having a boiling range within the range from 26 75-650F and containing monocyclic aromatics.
27 In one preferred embodiment~ the rnethod of the invention 28 is employed to extract bitumen from deposits of bituminous sand in 29 a subterranean body of the bituminous sand. I have found that the preferred solvent o~ the oresent invention, including a l~ixture of 31 acetone and 2-butanone, has the unusual property of extracting 32 fro~n at least some tyPeS of bituminous sand, in addition to the bitumen, a clay fraction which has metal values such that it is advantageous to recover the clay from subterranean deposits oE the bituminous sand. Thus, according to one preferred mode of operating the invention, a mixture of acetone and 2-butanone is employed to recover both bitumen and metals-bearing clay from the sand and, thereaE~er, the metals~bearing clay can be sep~aked from the bitumen and separately processed for recovery of the metals. In cases where a hydrocarbon component is combined with the solvent, I have found that the metals-bearing clay is substantially not extracted and remains associated in the particulate solids with the sand fraction. Thus, it is L0 easy to separate the bitumen and solvent Erom the clay and/or sand simplyby adding the hydrocarbon componen' at any desired phase of the solvent extrac-tion operation.
Thus this invention provides a method for separating hydrocarbon-aceous component from bituminous sand, comprising:
(a) forming a liquid phase including said hydrocarbonaceous com-ponent and a liquid solvent by contacting said liquid solvent with said bituminous sand; said liquid solvent comprising at least one ketone having the formula 0 Rl -- C - R2 wherein R and R are each alkyl groups having Erom 1 to 5 carbon atoms, and wherein R and R2 together inrlude from 2 to 7 carbon atoms; and (b) separating at least a portion of said liquid phase from at least an inorganic solid fraction of said tar sand.

In a preferred embodiment this invention provides a method for separating a hydrocarbonaceous component from a mixture including a major proportion oE a solid inorganic component and a minor proportion of said hydrocarbona~eous component, comprising:
(a) forming a liquid phase including said hydrocarbonaceous com-ponent and a liquid solvent by contacting said liquid solvent with said mixture, said liquid solvent comprising acetone and 2-butanone and having from 0.1 to 1.0 volume of 2-butanone per volume of acetone therein; and (b) separating at least a portion of said liquid phase from at least a fraction of said solid inorganic component.
DESCRIPTION OF THE DRAWING
The attached drawing is a schematic illustration of a preferred embodiment oE the present invention.
Referring to the drawing, bituminous sand is stored in a bln 1 and is fed via line 3 onto a moving conveyor belt 5. The belt 5 i8 perfor-ated to permit liquid flow through it. The belt 5, with bituminous sand thereon, moves into a housing 7. A mixture of acetone and 2-butanone is introduced into the housing through a line 9. One portion of the mixture in line 9 is divided out and passed into a line 11. The remainder passes further throught line 9 into a distributor-sprayer 13. The mixture of acetone and

2-butanone is sprayed from the sprayer 13 onto the bituminous sand on the belt 5, dissolving bltumen and forming a liquid phase. The liquid phase passes through the belt S and falls into a collection vessel 15, and ls re-moved from the housing 7 through a line 17 for processing to recover the solvent. Xylene solvent ls introduced into the housing or through line 19 and is conveyed to a second distributor-sprayer 21. The xylene is - 5a -~?J98'~0 01 sprayed from the sprayer 21 onto the solids on the belt 5, dis-02 solving further bitumen and forming a second liquid phase. The 03 second liquid phase passes through the belt 5 and falls into a 04 collection vessel 23, and is removed rom the housing 7 or 05 further processing through a line 25. The solids remaining on the 06 belt 5 pass further through the housing 7, and are sprayed with 07 another portion of the acetone/2-butanone mixture via the line 11 08 and a distributor-sprayer 27. The remainder of the bitumen is 09 thereby dissolved, forming a liquid phase which passes throu~h the belt 5 and falls into a collection vessel 29. This third liquid 11 phase is removed through a line 31 for further processing. Parti-12 tions 33, 35 and 37 prevent mixing of xylene-containing liquids 13 with acetone and 2-butanone-containing liquids. The residual, pri-14 marily inor7anic solids, remaining on the belt 5 after it 2asses through the partition 37, are stripped of solvent by passing 16 upwardly through the belt 5 a gas introduced throu~h a line 39 and 17 distributed by a distributor 41. Solvent-containing vapors are 18 removed from the housing 7 throuqh a line 43 for condensation and 19 recovery (not shown). The walls of the housin~ 7 and the parti-tions 33, 35 and 37, through which the belt 5 passes, are provided 21 with means (not shown) f~r preventing the escape of any substan-22 tial quantities of vapor or splashed liquids, e.~., flexible flaps 23 which maintain contact with the solid surface of the belt or oE
24 any bituminous sand thereon. After leaving the housing 7, the spent sands fall from the belt 5 into a spent sand receptacle ~5 26 for disposal. ~he belt 5 is held movably in position by a 27 olurality of rollers, such as those shown at 47, and is moved by 28 rotatin~ a roller using motor means 49.
29 For the sake of brevity, various necessary conventional elements, such as pumps, controlling e~ui~ment, etc. have not been 31 shown or described, their use and placement in the system 32 described bein~ apparent.

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01 DETAILED DESCRIPTION QE` THE INVENTIO~J
02 The present invention is preferably employed for recov-03 ering a desired hydrocarbonaceous component, such as bitumen or 04 the like from mix~ures of a minor proportion of a hydrocarbon-05 aceous component with a major proportion of an inor~anic solid 06 component, such as bituminous sands or similar materialsO The 07 ter~ "bituminous sand" includes a variety of naturally occurring 08 mixtures of tar, oil or bitumen with particulate inor~anic solids 09 such as sand and clay.
According to the present method, hydrocarbons are 11 recovered from bituminous sand and the li~e by (1) contacting the 12 liquid solvent with the bituminous sand to -for~ a liquid phase con-13 taining the solvent and bitumen and (2) separating the liquid 14 phase from the residual inorganic solids and residual nonflowable hydrocarbonaceous material.
16 The solvent used in the process of the present invention 17 includes at least one ketone of the formula:
18 o 19 ,.
Rl _ C - R2 22 where Rl and R2 are each alkyl groups having from 1 to 5 carbon 23 atoms, i.e., selected from methyl, ethyl, the propyl isomers, the 24 butyl isomers and the amyl isomers, and where Rl and R2 to~ether include from 2 to 7 carbon atoms. Preferably the solvent also 26 includes acetone~ Particularly preferably, the solvent used in 27 the present method comprises a .~ixture of acetone and 2-butanone.
28 The relative proportions of these two components of the solvent 29 are preferably such that the solvent contains at least 0.1 volume r and not more than 1.0 volume of 2-butanone for each volume of 31 ~cetone. For use with bituminous sand, a solvent including from 32 0.2 to 0.5 volume of 2-butanone per volume of acetone is espe-33 cially useful.

34 I have found that mixtures of acetone and 2-butanone in

3~ the indicated preferred pro~ortions are surprisinglv active for ~L?~8~30 01 separating bitumen from bituminous sand. Vpon contacting thi~
02 type of solvent with the tar sand, the solvent and bitumen ~o~ a 03 flowable liquid phase which is easily separated from the solid 04 residue by, for example, simple decantation or settling. The ~ 05 volatile solvent can then be separated easily from the heavy, hi~h-06 boiling bitumen by heating the solvent-bitumen liquid to vaporize 07 the solvent, leaving the bitumen in relatively pure form.
08 ~7hen the solvent consists essentially solely of acetone 09 and 2-butanone, an inorganic clay fraction can also be removed from at least some types of bituminous sand along with the 11 bitumen. The clay fraction associated ~ith the bitumen-solvent 12 liquid is in the nature of a suspension or colloid. In many -13 cases, recovery of clay from bituminous sand is desirable in that 14 the clay contains valuable metals which may be recovered from the concentrated clay. In other cases, it may be ad~antageous to 16 reject a clay fraction contained in the sand along with the other 17 inorganic residual solids. I have found that this and other advan-18 tages may be obtained by includin~ in the solvent, in addition to 19 the ketone, or the ketone and acetone, e.g., acetone and 2-buta-none, a hydrocarbon component. Suitable hydrocarbons are those 21 havin~ from 5 to 15 carbon atoms per molecule. Aromatic hydro-22 carbons are especially suitable, particularly benzene and mono-23 cyclic alkylaromatics. The hydrocarbon component of the sol~ent 24 may be a mixture of hydrocarbons, such as a hydrocarbon fraction boiling above 75F and below 650F. The hydrocarbon component of 26 the solvent, when employed, is included therein in amounts suffi-27 cient to provide from 0.1 to 3.0 volumes of the hydrocarbon compo-28 nent for each volume of acetone in the solvent. Preferably, the 29 amount of hydrocarbon provides from 0.2 to 0.5 volume of the hydro- -carbon component per volume of acetone. If no acetone is used, 31 the volumes of hydrocarbon used are from 0.1 to 3.0 volumes per 32 volume of ketone, preferably from 0.2 to 0.5 volume.

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01 In one mode of operation of the ~resent method, the 02 hydrocarbon component of the solvent is added after the bitu~inous 03 sand has been treated with a solvent, such as acetone and 2-buta-04 none, to form a liquid phase, so that the clay ractlon o the tar 05 sand is extracted in association with the li~uid phase containing 06 the solvent and bitu~en. By first recovering both the bitumen and 07 clay from the bituminous sand, and then adding the hydrocarbon 08 component of the solvent to the resulting clay-containing liquid 09 phase, the clay can thereby be recovered separately as a precipi-tate and processed to recover metal values or employed for any 11 other desired use. Thereafter, the bitumen can be separated from 12 the hydrocarbon, acetone and 2-butanone components of the solvent 13 simply by flashing off the light, low-boiling solvent components.
14 In general, since it is advantageous to make separation of the hydrocarbon component of the solvent from the admixture with the 16 bitumen as easy as is the separation of the acetone and 2-buta-17 none, the hydrocarbon component employed should have a boiling 13 point substantially below the initial boiling point of the bitumen 19 to be extracted and comparable to the acetone and 2-butanone.
Typically, 95 percent or more of the bitumen boils above 400F.
21 Tllus, hydrocarbons having a boiling point below 400F are mos~
22 convenient for use because of their ease of separation from the 23 bitumen.
24 In one preferred mode of operation the soivent is contacted ~ith the bituminous sand in a solvent extraction zone at 26 solvent extraction conditions. Suitable means constituting 27 solvent extraction zones, such as vessels, columns, etc., are 28 known in the art. The extraction step may be Qerformed in a batch-29 type operation or in a continuous-type operation using co-current 3G or countercurr nt contact between the solvent and the bituminous 31 sand. Use of a series of two or more extraction staaes involving 32 co-current contacting in one sta~e and countercurrent contacting 33 _9_ 01 in another is often advantageous. Solvent extraction conditions 02 include a temperature and pressure sufficient to maintain the 03 solvent component~ in the liquid phase. A preferred temperature 04 range is from 0F to 200JF, with the pressure employed being that 05 required to maintain liquid phase conditions. Contact time 06 between the bituminous sand and solvent should normally be suffi-07 cient so that a substantial fraction of the bitumen in the sand 08 forms a liquid phase including bitumen and the solvent. By "a sub-09 stantial fraction" is meant at least 1 percent o~ the extrac-table bitumen contained in the bituminous sand prior to treatment.11 Contact times of ten minutes or less are ~reÇerred. Normally, the 12 volume ratio of solvent to bituminous san~ empIoyed in the extrac-13 tion zone should preferably be between 0.1:1 and 2:1.
14 In another mode of operation, the solvent is introduced into a subterranean body of bituminous sand. This mode is particu-16 larly advantageous where the depth of unproductive overburden 17 materials is great enough that mining the tar sand is uneconomi-18 cal. The solvent can be introduced into a bituminous sand bed at 19 one point or, preferably, at a plurality of points in the bed.
The solvent and bitumen form a flowable liguid phase which can be 21 withdrawn from a subterranean body at one point or a plurality of 22 points where wells may be drilled. The particular mode of intro-23 duction or injection of the solvent into the bituminous sand body, 24 as well as the particular ~ode of removal of the liquid phase con-taining the bitumen and solvent, will, of course, depend at least 26 in part upon the type of geologi~al formation in which the tar 27 sand bed is located. Channels of flow between the injection and 28 production wells may be established according to various well-29 known procedures. Steam, carbon dioxide or other gases may, in some cases, be advantageously introduced into the bituminous sand 31 body to facili~ate fracturing and maintainance of flow channels, 32 etc. Where it is desired to remove a clay fraction from the bitu 33 minous sand bed along with the bitumen and solvent5 the type of 01 solvent introduced i5 preferably simply a mi~ture of acetone and Z-02 butanone. In this case, after the liquid phase containing the 03 solvent and bitumen, as well as suspended clay, has been pumped to 04 the surface, a hydrocarbon component, such as a Cs-Cg aromatic 05 fraction, can be mixed with the material recovered from the well, 06 thereby agglomerating the clay for easy recovery by decantation 07 from the liquid phase. The solvent components can then be sepa-08 rated from the bitumen by, for example, flash vaporization.
09 In using the solvent of the present invention, water present in the tar sand feed may be taken up in admi~ture with the 11 solvent during the extraction. If the amount of water in the sol-12 vent builds up to an undesirably high level, then the water can be 13 removed, or at least the level can be reduced, by fractionation.
14 In cases where the solvent and water are not easily separated by fractionation, e.g., ~hen the solvent and water form an azeotrope, 16 the solvent can be separated from the water by other means such as 17 adsorbing water on hydrophilic molecular sieves, or adsorbing the 18 solvent on hydrophobic molecular sieves.
19 The following illustrative embodiment sets forth a pre-ferred mode of operation of the present invention as utilized for 21 the extraction of bitumen from bituminous sands.
22 THE ILLUSTRATIVE_EMBODIMENT
23 In the preferred embodiment, the system shown in the 24 attached drawing is employed. Bituminous sand is passed onto the belt 5 and then throuqh the housing 7, The belt 5 is perforated 26 and includes 80 mesh openings. A liquid mixture of acetone and 2 27 butanone is sprayed on the tar sand from the distributor-sprayer 28 13 at the rate of 0.1 to 1 volume per volume of bituminous sand.
29 The mixture employed contains 0.3 volume of 2-butanone for each volume of acetone. A temperature of 110F and atmospheric 31 pressure are employed in the housinq 7 and 33 to provide preferred 32 solvent extraction conditions. A liquid phase mixture of about 60 01 volume percent bitumen and 40 volu~e percent acetone/2-butanone 02 solvent is removed from the collector 15 through the conduit 17 03 and is removed from the operation. The bituminous sand i5 then 04 sprayed with xylene ~rom the distributor 21 in an amount o 0 1 to 05 1 volume per volume of the sand. The resultin~ mixture o~ bitumen 06 and xylene is removed from the collector 23 through the line 25 07 and passed out of the operation. The sand is then sprayed with a 08 second portion of the acetone/2-butanone mixture from the distribu-09 tor 27. The amount used is a 0.2 volume per volume of solids.
The resulting liquid-phase mixture of bitumen, acetone, 2-butanone ll and any residual xylene is removed from the collector 29 and 12 passed out of the operation through the conduit 31. The residual 13 sand is then dried and freed from solvent by passing a stream of 14 nitrogen upwardly through it from the distributor 41. The solvent vapor can be condensed and recovered from the nitrogen drying 16 stream after removal from the housing 7. The dried, residual sand 17 is carried out of the housing 7 on tne belt 5 and dumped into the 18 spent sand receptacle 45 for disposal.
l9 A preferred embodiment of the invention having been described, a large number of equivalent variations and ~odifi-21 cations within the scope of the appended clai~s will be apparent 22 to those skilled in the art.

Claims (17)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method for separating a hydrocarbonaceous component from bituminous sand, comprising:
(a) forming a liquid phase including said hydrocarbonaceous component and a liquid solvent by contacting said liquid solvent with said bituminous sand, said liquid solvent comprising at least one ketone having the formula where R1 and R2 are each alkyl groups having from 1 to 5 carbon atoms, and wherein R1 and R2 together include from 2 to 7 carbon atoms; and (b) separating at least a portion of said liquid phase from at least an inorganic solid fraction of said tar sand.

2. A method according to Claim 1 wherein said liquid solvent is contacted with said bituminous sand in an extraction zone at extraction conditions.

3 A method according to Claim 1 wherein said liquid sol-vent further includes from 0.1 to 3.0 volumes of a hydrocarbon component per volume of ketone therein, said hydrocarbon component comprising at least one hydrocarbon having from 5 to 15 carbon atoms per molecule.

4. A method according to Claim 3 wherein said hydrocarbon component comprises at least one member of the group of benzene and monocyclic alkylaromatic hydrocarbons.

5. A method according to Claim 3 wherein said hydrocarbon component comprises a hydrocarbon fraction having a boiling range within the range from 75°F to 650°F.

6. A method according to Claim l wherein said liquid solvent is intro-duced into a subterranean body of bituminous sand.

7. A method according to Claim 6 wherein said bituminous sand includes a clay fraction and a sand fraction, and at least a portion of clay fraction is withdrawn from said body in association with said liquid phase.

8. A method according to Claim 7 wherein at least a portion of the clay fraction associated with said liquid phase is precipitated therefrom by con-tacting said clay and said liquid phase with a hydrocarbon having from 5 to 15 carbon atoms per molecule.

9. A method for separating hydrocarbonaceous component from a mixture including a major proportion of a solid inorganic component and a minor proportion of said hydrocarbonaceous component, comprising:
(a) forming a liquid phase including said hydrocarbonaceous com-ponent and a liquid solvent by contacting said liquid solvent with said mix-ture, said liquid solvent comprising acetone and 2-butanone and having from 0.1 to 1.0 volume of 2-butanone per volume of acetone therein; and (b) separating at least a portion of said liquid phase from at least a fraction of said solid inorganic component.

10. A method according to Claim 9 wherein said mixture is a bituminous sand.

11. A method according to Claim 10 wherein said liquid solvent is con-tacted with said bituminous sand in an extraction zone at extraction conditions.

12. A method according to Claim 11 wherein said liquid solvent further includes from 0.1 to 3.0 volumes of a hydrocarbon component per volume of acetone therein, said hydrocarbon component comprising at least one hydro-carbon having from 5 to 15 carbon atoms per molecule.

13. A method according to Claim 12 wherein said hydrocarbon component comprises at least one member of the group of benzene and monocyclic alkyl-aromatic hydrocarbons.

14. A method according to claim 12 wherein said hydrocarbon component comprises a hydrocarbon fraction having a boiling range within the range from 75°F to 650°F.

15. A method according to Claim 10 wherein said liquid solvent is introduced into a subterranean body of bituminous sand.

16. A method according to Claim 15 wherein said bituminous sand includes a clay fraction and a sand fraction, and at least a portion of said clay fraction is withdrawn from said body in association with said liquid phase.

17. A method according to Claim 16 wherein at least a portion of the clay fraction associated with said liquid phase is precipitated therefrom by contacting said clay and said liquid phase with a hydrocarbon having from 5 to 15 carbon atoms per molecule.