US3894770A - Wellbore oxidation of lixiviants - Google Patents
Wellbore oxidation of lixiviants Download PDFInfo
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- US3894770A US3894770A US478437A US47843774A US3894770A US 3894770 A US3894770 A US 3894770A US 478437 A US478437 A US 478437A US 47843774 A US47843774 A US 47843774A US 3894770 A US3894770 A US 3894770A
- Authority
- US
- United States
- Prior art keywords
- pregnant liquor
- gas
- lift
- wellbore
- oxidation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000007254 oxidation reaction Methods 0.000 title claims abstract description 58
- 230000003647 oxidation Effects 0.000 title claims abstract description 56
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 claims abstract description 58
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 37
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 37
- 239000001301 oxygen Substances 0.000 claims abstract description 37
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims abstract description 36
- 239000007789 gas Substances 0.000 claims abstract description 27
- 229910001448 ferrous ion Inorganic materials 0.000 claims abstract description 14
- 229910052751 metal Inorganic materials 0.000 claims abstract description 14
- 239000002184 metal Substances 0.000 claims abstract description 14
- 230000003190 augmentative effect Effects 0.000 claims abstract description 3
- 238000000034 method Methods 0.000 claims description 60
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 43
- 230000008569 process Effects 0.000 claims description 41
- 238000006243 chemical reaction Methods 0.000 claims description 38
- 238000011065 in-situ storage Methods 0.000 claims description 24
- 229910052742 iron Inorganic materials 0.000 claims description 20
- 239000011790 ferrous sulphate Substances 0.000 claims description 15
- 235000003891 ferrous sulphate Nutrition 0.000 claims description 15
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims description 14
- 229910000359 iron(II) sulfate Inorganic materials 0.000 claims description 14
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 claims description 12
- 239000002253 acid Substances 0.000 claims description 12
- 239000007788 liquid Substances 0.000 claims description 11
- 230000001590 oxidative effect Effects 0.000 claims description 9
- 229910001447 ferric ion Inorganic materials 0.000 claims description 7
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 5
- 235000010755 mineral Nutrition 0.000 claims description 5
- 239000011707 mineral Substances 0.000 claims description 5
- 239000010949 copper Substances 0.000 abstract description 36
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 abstract description 35
- 229910052802 copper Inorganic materials 0.000 abstract description 35
- 238000011084 recovery Methods 0.000 abstract description 24
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 abstract description 13
- 238000012545 processing Methods 0.000 abstract description 10
- 239000000243 solution Substances 0.000 description 38
- 238000005065 mining Methods 0.000 description 23
- 238000004519 manufacturing process Methods 0.000 description 19
- RUTXIHLAWFEWGM-UHFFFAOYSA-H iron(3+) sulfate Chemical compound [Fe+3].[Fe+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O RUTXIHLAWFEWGM-UHFFFAOYSA-H 0.000 description 12
- 229910000360 iron(III) sulfate Inorganic materials 0.000 description 12
- 241000894006 Bacteria Species 0.000 description 8
- 230000000694 effects Effects 0.000 description 8
- 238000002386 leaching Methods 0.000 description 7
- 230000001580 bacterial effect Effects 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 5
- 238000005755 formation reaction Methods 0.000 description 5
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 5
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 4
- 239000003054 catalyst Substances 0.000 description 4
- 230000001419 dependent effect Effects 0.000 description 4
- 230000002829 reductive effect Effects 0.000 description 4
- 238000012546 transfer Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 230000002706 hydrostatic effect Effects 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 239000011734 sodium Substances 0.000 description 3
- 229910052708 sodium Inorganic materials 0.000 description 3
- 239000011593 sulfur Substances 0.000 description 3
- 229910052717 sulfur Inorganic materials 0.000 description 3
- 241000605222 Acidithiobacillus ferrooxidans Species 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- 241000196324 Embryophyta Species 0.000 description 2
- 241000184339 Nemophila maculata Species 0.000 description 2
- 238000013459 approach Methods 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 230000002939 deleterious effect Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
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- 230000000266 injurious effect Effects 0.000 description 2
- 238000011835 investigation Methods 0.000 description 2
- 230000000670 limiting effect Effects 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000008929 regeneration Effects 0.000 description 2
- 238000011069 regeneration method Methods 0.000 description 2
- 239000011435 rock Substances 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 241001246312 Otis Species 0.000 description 1
- 229920001213 Polysorbate 20 Polymers 0.000 description 1
- 241000982035 Sparattosyce Species 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- PIYVNGWKHNMMAU-UHFFFAOYSA-N [O].O Chemical compound [O].O PIYVNGWKHNMMAU-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 229910052948 bornite Inorganic materials 0.000 description 1
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical class [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 1
- 235000011132 calcium sulphate Nutrition 0.000 description 1
- 229910052947 chalcocite Inorganic materials 0.000 description 1
- 229910052951 chalcopyrite Inorganic materials 0.000 description 1
- DVRDHUBQLOKMHZ-UHFFFAOYSA-N chalcopyrite Chemical compound [S-2].[S-2].[Fe+2].[Cu+2] DVRDHUBQLOKMHZ-UHFFFAOYSA-N 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000012993 chemical processing Methods 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000003841 chloride salts Chemical class 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- BWFPGXWASODCHM-UHFFFAOYSA-N copper monosulfide Chemical compound [Cu]=S BWFPGXWASODCHM-UHFFFAOYSA-N 0.000 description 1
- 229910000365 copper sulfate Inorganic materials 0.000 description 1
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 1
- OMZSGWSJDCOLKM-UHFFFAOYSA-N copper(II) sulfide Chemical compound [S-2].[Cu+2] OMZSGWSJDCOLKM-UHFFFAOYSA-N 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- -1 i.e. Substances 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 229960004717 insulin aspart Drugs 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- GDPKWKCLDUOTMP-UHFFFAOYSA-B iron(3+);dihydroxide;pentasulfate Chemical compound [OH-].[OH-].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O GDPKWKCLDUOTMP-UHFFFAOYSA-B 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- VOMXSOIBEJBQNF-UTTRGDHVSA-N novorapid Chemical compound C([C@H](NC(=O)[C@H](CC(C)C)NC(=O)[C@H](CO)NC(=O)[C@H](CS)NC(=O)[C@H]([C@@H](C)CC)NC(=O)[C@H](CO)NC(=O)[C@H]([C@@H](C)O)NC(=O)[C@H](CS)NC(=O)[C@H](CS)NC(=O)[C@H](CCC(N)=O)NC(=O)[C@H](CCC(O)=O)NC(=O)[C@H](C(C)C)NC(=O)[C@@H](NC(=O)CN)[C@@H](C)CC)C(=O)N[C@@H](CCC(N)=O)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CCC(O)=O)C(=O)N[C@@H](CC(N)=O)C(=O)N[C@@H](CC=1C=CC(O)=CC=1)C(=O)N[C@@H](CS)C(=O)N[C@@H](CC(N)=O)C(O)=O)C1=CC=C(O)C=C1.C([C@@H](C(=O)N[C@@H](CC(C)C)C(=O)N[C@H](C(=O)N[C@@H](CCC(O)=O)C(=O)N[C@@H](C)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CC=1C=CC(O)=CC=1)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](C(C)C)C(=O)N[C@@H](CS)C(=O)NCC(=O)N[C@@H](CCC(O)=O)C(=O)N[C@@H](CCCNC(N)=N)C(=O)NCC(=O)N[C@@H](CC=1C=CC=CC=1)C(=O)N[C@@H](CC=1C=CC=CC=1)C(=O)N[C@@H](CC=1C=CC(O)=CC=1)C(=O)N[C@@H]([C@@H](C)O)C(=O)N[C@@H](CC(O)=O)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H]([C@@H](C)O)C(O)=O)C(C)C)NC(=O)[C@H](CO)NC(=O)CNC(=O)[C@H](CS)NC(=O)[C@H](CC(C)C)NC(=O)[C@H](CC=1NC=NC=1)NC(=O)[C@H](CCC(N)=O)NC(=O)[C@H](CC(N)=O)NC(=O)[C@@H](NC(=O)[C@@H](N)CC=1C=CC=CC=1)C(C)C)C1=CN=CN1 VOMXSOIBEJBQNF-UTTRGDHVSA-N 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 238000010979 pH adjustment Methods 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 235000010486 polyoxyethylene sorbitan monolaurate Nutrition 0.000 description 1
- 239000000256 polyoxyethylene sorbitan monolaurate Substances 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 230000003134 recirculating effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000009877 rendering Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000012163 sequencing technique Methods 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 229910052569 sulfide mineral Inorganic materials 0.000 description 1
- DHCDFWKWKRSZHF-UHFFFAOYSA-N sulfurothioic S-acid Chemical compound OS(O)(=O)=S DHCDFWKWKRSZHF-UHFFFAOYSA-N 0.000 description 1
- 235000011149 sulphuric acid Nutrition 0.000 description 1
- 239000001117 sulphuric acid Substances 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 230000005641 tunneling Effects 0.000 description 1
- 150000003751 zinc Chemical class 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/28—Dissolving minerals other than hydrocarbons, e.g. by an alkaline or acid leaching agent
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S423/00—Chemistry of inorganic compounds
- Y10S423/09—Reaction techniques
- Y10S423/17—Microbiological reactions
Definitions
- ABSTRACT Recovery of metal values such as copper values from a wellbore is combined with the pregnant liquor treatment to achieve aspart of the recovery operation the pregnant liquor processing; during a gas-lift operation of the pregnant liquor ferrous ions in the pregnant liquor are being oxidized and a suitable lixiviant is obtained for reintroduction in the wellbore; as an embodirnent of the invention sulfur dioxide augmented oxygen containing gas is used for treating the pregnant liquor to aid the oxidation and generate sulfuric acid being used up during the copper value recovery.
- This invention relates to the mining of metals, such as copper; more particularly, this invention pertains to the in-situ recovery of metal values associated with sulfidic deposits, such as sulfidic deposits bearing copper values in ore formations lying at great depths. Still further, this method pertains to in-situ wellbore oxidation of lixiviants in a production well in which a metal recovery such as copper recovery is sought to be joined with lixiviant or leaching liquor processing during the transportation of metal values, such as copper values from a wellbore by a gas-lift.
- Certain types of bacteria use ferrous ions as an energy source. In the process such bacteria convert the ferrous ions to the ferric state. The bacterial activity is dependent on pH, temperature, degree of exposure to sunlight and oxygen availability. Solid surfaces are required to permit the growth of colonies. Certain operating conditions will be very injurious to bacterial growth, thus the process requires careful control. Bacterial oxidation has been carried out in both the laboratory and in waste copper leaching dumps. Although possible, it is not thought to be a likely candidate in a gas-lift operation in in-situ mining processes.
- the concept of bacterial oxidation has been largely derived from dump leach experience. It is believed that bacteria play an important role in the dump leaching process. Detailed investigations have demonstrated that two strains of bacteria, namely the thiobacillus ferrooxidans and the thiobacillius thiooxidans, are present in mine water.
- the thiobaccilus ferrooxidans are capable of oxidizing dissolved ferrous iron to the ferric state, while the thiobaccillus thiooxidans are capable of oxidizing elemental sulfur to sulfuric acid. Both strains will oxidize thiosulfate to sulfuric acid.
- bacteria are autotropic, deriving their energy from the iron and sulfuric oxidizing reactions.
- some organic compounds help increase their activity; one such compound is Tween-20.
- the principal constraints on the system include: first, in a system using bacterial oxidation the maximum ferric iron concentration should not exceed 15 g/l optimum. A higher concentration of iron is toxic to bacteria.
- bacteria require solid surfaces for their growth and regeneration. In an open pond which would be the most logical choice for the storage of large volumes of ferric sulfate solutions, there may have to be a provision for rock pile colonization areas. A given surface area would be required, the depth below pond surface and compatibility of such colonization areas with the need for pond dredging is a problem. It may not be feasible to provide colonies in production tubing.
- ferric sulfate oxidizes copper sulfide minerals, it reduces to ferrous sulfate.
- ferric sulfate In an in-situ mining operation where ferric sulfate is used as the lixiviant, the pregnant solution coming out of the ground is expected to contain substantial quantities of ferrous sulfate.
- the process is practiced by removal of a column of frothed liquid lixiviant (which is frothed by a suitable gas such as air or enriched air or sulfur dioxide supplemented air).
- a suitable gas such as air or enriched air or sulfur dioxide supplemented air.
- An oxidizing gas such as oxygen or air enriched with oxygen and/or supplemented with sulfur dioxide is employed either with or without a suitable catalyst to work on the pregnant liquor.
- the liquor is thus substantially fully treated by the time it arrives at the surface and the ferrous to ferric conversion is achieved.
- gas-lift for removing liquids from wellbores conventionally practiced has further been enhanced by a processing combination relying on time, temperature, pressure and additionally a catalyst such as the metal ion in solution or S0 which allows a more facile practicing of the in-situ technique of mining deep lying ore formations.
- a processing combination relying on time, temperature, pressure and additionally a catalyst such as the metal ion in solution or S0 which allows a more facile practicing of the in-situ technique of mining deep lying ore formations.
- the most desirable conditions for air oxidation at normal pressure and temperature are such that the total iron content be less than 25 g/l (preferably less than g/l) and the solution pH be lower than 2. If the total iron content (all of which can be as ferrous ion) is more than 25 g/l, practically no oxidation takes place within a period of two weeks. If the pH is higher than 2, iron begins to precipitate as a basic ferric sulfate, thus reducing the potential of the solution as a lixiviant for copper containing minerals.
- the total iron content all of which can be as ferrous ion
- Air oxidation can be greatly accelerated by raising the temperature and the pressure. As above, pH adjustment is important to prevent precipitation of iron. The reaction rate can be accelerated to the point that the required oxidation can be carried out in a few minutes.
- the oxidation of ferrous sulfate by S0 and air (or oxygen) is said to be very rapid in the order of 1/2 hour for 90% conversion under controlled conditions.
- Ferrous sulphate solution containing appreciable amounts of free acid causes the rate of oxidation to be substantially slower while the formation of acid is also hindered. If the starting solution is lightly acidic, a period of induction was observed during which it was hard to get the oxidation reaction started. After the period of induction was over, more acid could be formed and more ferrous sulfate oxidized in spite of the accumulation of acid.
- the concentration of ferrous iron is practically immaterial as long as the solution contains enough available ferrous iron to react with oxygen and sulfur dioxide as fast as they are effectively supplied. This means that mass transfer of S0 and oxygen to the solution is the rate limiting parameter. It is with respect to the mass transfer considerations in the gas-lift in in-situ mining that the discovery has been made on how to utilize these complex interactions to achieve the processing of the pregnant liquor for reuse in a functionally double duty approach.
- the rate of formation of sulfuric acid is not as sensitive as the oxidation reaction, but it is also impaired by too high concentration of sulfur dioxide.
- the maximum percentage of sulfur dioxide permissible in a mixture is capable of being increased to 5-7% by volume (80 20 1:2.75).
- S can be introduced as solution (i.e. liquid S0 and air is introduced as 1 mm bubbles, over 10% of S0 based on volume of air (80 10 1:1.86) can be used, e.g., up to 12%.
- the ratio of S0 to O i.e., air
- the ratio of S0 to O can be doubled in a second step as part of the process in order to favor the formation of acid.
- Alminum and zinc salts even at high concentrations (2 to 25 g/l), do not significantly affect the rates of reaction.
- the leaching liquor after appropriate residence time is being removed from the wellbore as a pregnant liquor.
- the residence time in the wellbore is generally from 5 to 120 minutes while the temperature is in the range from 30 to 130C.
- t may be from 300 to 2200 psi depending on the hydrostatic or overpressure being exerted on the well. Hydrostatic pressure is about 435 psi for each 1,000 ft of water below the water table.
- pregnant liquor is a dilute sulphuric acid solution having a specific gravity of 1.1 and containing dissolved salts including iron, copper, and other metals.
- the pH of the liquor ranges from 0 to 3.
- the pressure at the bottom of a production well will range between the hydrostatic pressure created by the static column of fluid in the well to a flowing bottom hole pressure.
- the flowing bottom hole pressure will depend on the desired rate of production and the productivity index, i.e. the rate of fluid production per unit pressure drop.
- the temperature is proportional to depth and in igneous rock invironments, a general approximation is a temperature gradient of 2F per 100 ft. of depth beneath the surface. Therefore, the temperature will be some average ambient temperature plus the gradient times depth divided by 100. In addition, the temperature may be increased by the oxidation process in the production tubing.
- the rate of oxidation of ferrous ion to ferric ion will depend on the temperature, pressure, catalytic effects of either dissolved ions; or any other catalytic agents that are added. At moderate contact time (between oxygen in the lifting gas and the solution), depending on the rate of production and height of lift, the conversion will be expected to approach 100%. Contact times may range from 5 minutes to 2 hours.
- the normal residence time of a unit of pregnant liquor in a 2000 ft. wellbore is 4.4 min. if the production rate is 100 gal/min. or 44 minutes if the production rate is 10 gal/min).
- residence time at 100 and 10 gal/min productions rates is l l min. to 1 10 min. respectively.
- the residence time of the liquor is generally sufficient to convert up to l% of the ferrous ion to ferric ion, in the indicated range of bubble sizes i.e.
- reaction rate of ferrous ion to ferric ion is a function of pressure and temperature.
- the relatively higher pressure and temperature encountered in wells in in-situ mining of mineral deposits is thereby utilized as a reaction accelerating means during the actual gas-lift.
- the incorporation of the oxidation step (as well as an acid generating step) in the gas lift of pregnant liquor from the bottom of the well is an operating benefit which contributes to the optimization of the in-situ mining of mineral deposits.
- a gas-lift utilizing a conventional gas-life valve is installed with tubing in a well.
- Gas is injected into the annulus between the wellbore and tubing at pressures of 100 to 130 psi per 1000 ft. of depth but not less than 300 psi.
- the rate of gas injection is about 5 standard dubic ft. per gallon of liquid per l000 ft. of lift.
- the rate at which the pregnant liquor can be recovered can be further enhanced or slowed down by the capacity of the gas lift, the oxygen, the sulfur dioxide content in the gas lift, and the function of the gas .lift on the basis of the original lixiviant solution, temperature and pressure.
- the process of utilizing the gas lift to perform a multiple function contributes to the economic application of the in-situ process.
- the processing of the pregnant liquid in which coacting chemical reactions takes place during the removal of the pregnant liquid from a wellbore provides a desired aspect of the present combination of elements.
- the novel combination i.e. process may be practiced in a multiple well field, such as a five-spot pattern field, i.e. a central injection well and production wells in each corner of a generally rectangular pattern.
- an optimized sequencing of the recovery processes in which oxygen-water lixiviant system is used or ferric sulfate lixiviant'is used, pregnant liquor recovery is based on the process sequence in a total in-situ scheme of wellbore recovery of copper.
- the amount of lixiviant being introduced and the pregnant liquor being produced may likewise be scheduled in an appropriate sequence such that the total combination of wellbores are optimized in a predetermined pattern such as the mentioned five-spot hole array for the maximum utilization and processing of the recovery components and the end product, i.e., metal values.
- a huff-puff single well recovery method may be used and other techniques employed in combination with the process herein.
- a deposit, such as found near Safford, Arizona may be worked by the above described methods.
- a lixiviant is introduced into at least one wellbore and a pregnant liquor removed therefrom, the combination comprising: introducing in a wellbore a gas-lift comprising from 4 to ll scf of air per gallon of pregnant liquor lifted per 1000 ft.; maintaining in said gas-lift during said lift oxygen; lifting the pregnant liquor at a rate such that the residence time in the wellbore is about 5 minutes to 2 hours whereby the rate of oxidation of ferrous ions in said pregnant liquor is such that nearly conversion can be assured in a wellbore of at least 500 ft.; separating the pregnant liquor and oxygen for oxidizing the pregnant liquor; recovering said metal values in said pregnant liquor; and reintroducing a barren liquor in said wellbore.
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- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Treatment Of Water By Oxidation Or Reduction (AREA)
Abstract
Description
Claims (10)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US478437A US3894770A (en) | 1974-06-12 | 1974-06-12 | Wellbore oxidation of lixiviants |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US478437A US3894770A (en) | 1974-06-12 | 1974-06-12 | Wellbore oxidation of lixiviants |
Publications (1)
Publication Number | Publication Date |
---|---|
US3894770A true US3894770A (en) | 1975-07-15 |
Family
ID=23899931
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US478437A Expired - Lifetime US3894770A (en) | 1974-06-12 | 1974-06-12 | Wellbore oxidation of lixiviants |
Country Status (1)
Country | Link |
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US (1) | US3894770A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4080419A (en) * | 1976-12-10 | 1978-03-21 | The United States Of America As Represented By The Secretary Of The Interior | Foam injection leaching process for fragmented ore |
US6280501B1 (en) * | 1999-05-06 | 2001-08-28 | Lakefield Research Ltd. | Base metal recovery |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3278233A (en) * | 1964-03-27 | 1966-10-11 | Mobil Oil Corp | In situ leaching of subterranean deposits |
US3728430A (en) * | 1970-12-14 | 1973-04-17 | Anlin Co | Method for processing copper values |
US3841705A (en) * | 1973-09-27 | 1974-10-15 | Kennecott Copper Corp | Stimulation of production well for in situ metal mining |
-
1974
- 1974-06-12 US US478437A patent/US3894770A/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3278233A (en) * | 1964-03-27 | 1966-10-11 | Mobil Oil Corp | In situ leaching of subterranean deposits |
US3728430A (en) * | 1970-12-14 | 1973-04-17 | Anlin Co | Method for processing copper values |
US3841705A (en) * | 1973-09-27 | 1974-10-15 | Kennecott Copper Corp | Stimulation of production well for in situ metal mining |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4080419A (en) * | 1976-12-10 | 1978-03-21 | The United States Of America As Represented By The Secretary Of The Interior | Foam injection leaching process for fragmented ore |
US6280501B1 (en) * | 1999-05-06 | 2001-08-28 | Lakefield Research Ltd. | Base metal recovery |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: KENNECOTT CORPORATION Free format text: CHANGE OF NAME;ASSIGNOR:KENNECOTT COPPER CORPORATION;REEL/FRAME:004815/0016 Effective date: 19800520 Owner name: KENNECOTT MINING CORPORATION Free format text: CHANGE OF NAME;ASSIGNOR:KENNECOTT CORPORATION;REEL/FRAME:004815/0036 Effective date: 19870220 Owner name: KENNECOTT CORPORATION, 200 PUBLIC SQUARE, CLEVELAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:KENNECOTT MINING CORPORATION;REEL/FRAME:004815/0063 Effective date: 19870320 |
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Owner name: GAZELLE CORPORATION, C/O CT CORPORATION SYSTEMS, C Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:RENNECOTT CORPORATION, A DE. CORP.;REEL/FRAME:005164/0153 Effective date: 19890628 |
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Owner name: KENNECOTT UTAH COPPER CORPORATION Free format text: CHANGE OF NAME;ASSIGNOR:GAZELLE CORPORATION;REEL/FRAME:005604/0237 Effective date: 19890630 |