US4979986A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rapid oxidation process of carbonaceous and pyritic gold-bearing ores by chlorination
Assignee: Newmont Gold Co
•
Filing: 1988-02-22
•
Granted: 1990-12-25
•
Expires: 2008-02-22
Abstract
Abstract A method of treating a gold-bearing ore to render the gold component of the ore more amenable to standard cyanidation treatment in a reduced amount of time is disclosed. An aqueous slurry of the gold-bearing ore is introduced into at least one vessel. An oxidizing agent, such as chlorine gas, an alkali metal hypochlorite and an alkaline earth metal hypochlorite, is rapidly introduced into the vessel so that it intimately contacts the aqueous slurry. While the oxidizing agent is being introduced into the vessel, the slurry is agitated with agitating means including a plurality of impeller blades that provide high shear agitation and a large interfacial surface area between the oxidizing agent and the liquid phase of the slurry to enhance the mass transfer of the oxidizing agent so that it becomes substantially completely adsorbed by the aqueous slurry in about 5 to about 15 minutes.
Inventors
- 👤 David L. Hill
- 👤 Kenneth A. Brunk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 06:05
CPC Classifications
C; C22; C22B; C22B11/00; C22B11/04; C22B1/00; C22B11/08
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
103 words
A method of treating a gold-bearing ore to render the gold bearing portion of the ore more amenable to standard cyanidation treatment which comprises: introducing a slurry of the gold-bearing ore into at least one vessel; introducing an oxidizing agent into the at least one vessel so that it intimately contacts the slurry in an amount sufficient to oxidize or deactivate any carbonaceous and sulfidic mineral materials present in the ore; and agitating the slurry in a manner sufficient to permit the total amount of oxidizing agent to become substantially completely adsorbed by the aqueous slurry in about 5 to about 15 minutes.
Claim 2
Independent Claim
103 words
A method of treating a gold-bearing ore to render the gold bearing portion of the ore more amenable to standard cyanidation treatment which comprises: introducing a slurry of the gold-bearing ore into at least one vessel; introducing an oxidizing agent into the at least one vessel so that it intimately contacts the slurry in an amount sufficient to oxidize or deactivate any carbonaceous and sulfidic mineral materials present in the ore; and agitating the slurry in a manner sufficient to permit the total amount of oxidizing agent to become substantially completely adsorbed by the aqueous slurry in about 5 to about 15 minutes.
Claim 3
Dependent Claim
12 words
The method of claim 1 wherein the oxidizing agent is chlorine gas.
Claim 4
Dependent Claim
26 words
The method of claim 1 wherein the oxidizing agent is selected from the group consisting of an alkali metal hypochlorite and an alkaline earth metal hypochlorite.
Claim 5
Dependent Claim
30 words
The method of claim 2 wherein the chlorine gas is introduced into the vessel as the aqueous slurry is maintained at temperature of about 70° F. to about 125° F.
Claim 6
Dependent Claim
30 words
The method of claim 2 wherein the chlorine gas is introduced into the vessel as the slurry is maintained at a temperature of about 95° F. to about 110° F.
Claim 7
Dependent Claim
26 words
The method of claim 2 wherein the chlorine gas is introduced into the vessel as the slurry is maintained at a temperature of about 104° F.
Claim 8
Dependent Claim
44 words
The method of claim 1 wherein the slurry is agitated with agitating means including a plurality of impeller Plades that promote contact between the oxidizing agent and the liquid phase of the slurry so as to enhance the mass transfer of the oxidizing agent.
Claim 9
Dependent Claim
35 words
The method of claim 7 wherein the agitating means further include a shaft having a potential rotation speed of 190 rpm and wherein the impeller blades, when rotated, have a tip speed of 1270 ft./min.
Claim 10
Dependent Claim
17 words
The method of claim 1 wherein the slurry has a pH of about 2 to about 11.
Claim 11
Dependent Claim
60 words
The method of claim 9 which further comprises adding an acid to the aqueous slurry to reduce the pH of the slurry within a range of about 2 to about 6, prior to introducing the oxidizing agent into the vessel, to increase the rate at which the oxidizing agent will react with the carbonaceous and sulfidic constituents of the ore.
Claim 12
Dependent Claim
12 words
The method of claim 10 wherein the acid is a mineral acid.
Claim 13
Dependent Claim
15 words
The method of claim 11 wherein the mineral acid includes sulfuric, hydrochloric or nitric acid.
Claim 14
Dependent Claim
44 words
The method of claim 1 which further comprises dispersing an oxygen-containing gas through the slurry, prior to introducing the oxidizing agent into the slurry, to provide an amount in excess of that required for reaction with the carbonaceous and sulfidic constituents of the ore.
Claim 15
Dependent Claim
13 words
The method of claim 13 wherein the oxygen-containing gas includes oxygen or air.
Claim 16
Dependent Claim
19 words
The method of claim 1 wherein the slurry and the oxidizing agent are introduced into a plurality of vessels.
Claim 17
Dependent Claim
17 words
The method of claim 15 wherein the slurry and the oxidizing agent are introduced into four vessels.
Claim 18
Dependent Claim
44 words
The method of claim 1 wherein the ore contains from about 0.06 to about 1 or more ounces of gold per ton of ore, from about 0.1 to about 5% by weight of carbon and up to about 5% by weight of pyritic materials.
Claim 19
Dependent Claim
50 words
The method of claim 1 wherein the slurry is prepared by grinding the ore from about 50 to about 70 weight percent minus 200 mesh and pulping the ground ore with a sufficient amount of water to form an aqueous slurry with about 40 to about 50% solids in water.
Claim 20
Independent Claim
194 words
A method of treating a gold-bearing ore to render the gold bearing portion of the ore more amenable to standard cyanidation treatment which comprises: grinding the gold-bearing ore to about 50 to about 70 weight percent minus 200 mesh; pulping the ground ore with an amount of water to form a slurry with about 40 to about 50% solids in water; introducing the slurry of the gold-bearing ore into at least one vessel; dispersing an oxygen-containing gas through the aqueous slurry to provide in an amount which exceeds that required for reaction with the carbonaceous and sulfidic constituents of the ore; introducing chlorine gas into said at least one vessel so that it intimately contacts the slurry in an amount sufficient to oxidize or deactivate any residual carbonaceous and sulfidic constituents present in the ore; and agitating the slurry with agitating means including a plurality of impeller blades that promotes contact area between the chlorine gas and the liquid phase of the slurry to increased the mass transfer of the chlorine gas so that the total amount of chlorine gas becomes substantially completely adsorbed by the slurry in about 5 to about 15 minutes.
Claim 21
Independent Claim
194 words
A method of treating a gold-bearing ore to render the gold bearing portion of the ore more amenable to standard cyanidation treatment which comprises: grinding the gold-bearing ore to about 50 to about 70 weight percent minus 200 mesh; pulping the ground ore with an amount of water to form a slurry with about 40 to about 50% solids in water; introducing the slurry of the gold-bearing ore into at least one vessel; dispersing an oxygen-containing gas through the aqueous slurry to provide in an amount which exceeds that required for reaction with the carbonaceous and sulfidic constituents of the ore; introducing chlorine gas into said at least one vessel so that it intimately contacts the slurry in an amount sufficient to oxidize or deactivate any residual carbonaceous and sulfidic constituents present in the ore; and agitating the slurry with agitating means including a plurality of impeller blades that promotes contact area between the chlorine gas and the liquid phase of the slurry to increased the mass transfer of the chlorine gas so that the total amount of chlorine gas becomes substantially completely adsorbed by the slurry in about 5 to about 15 minutes.
Claim 22
Dependent Claim
30 words
The method of claim 19 wherein the chlorine gas is introduced into the vessel as the slurry is maintained at a temperature of about 70° F. to about 125° F.
Claim 23
Independent Claim
177 words
A method of recovering gold from a carbonaceous and pyritic gold-bearing ore which comprises: introducing a slurry of the gold-bearing ore into at least one vessel; introducing chlorine gas into the at least one vessel in intimate contact with the slurry and in an amount sufficient to oxidize or deactivate any carbonaceous and sulfidic mineral materials present in the ore and as the slurry is maintained at a temperature of about 70° F. to about 125° F.; agitating the slurry in a manner sufficient to permit the total amount of chlorine gas to become substantially completely adsorbed by the slurry in about 5 to about 15 minutes; maintaining the temperature of the slurry at between about 70° F. to about 125° F. for at least about 4 hours to allow the reaction mass to equilibrate with resulting passivation or alteration of the carbonaceous and sulfidic content of the ore so that it will not significantly sequester the gold content of the ore; and subjecting the ore to standard cyanidation treatment to recover an amount of gold therefrom.
Claim 24
Independent Claim
177 words
A method of recovering gold from a carbonaceous and pyritic gold-bearing ore which comprises: introducing a slurry of the gold-bearing ore into at least one vessel; introducing chlorine gas into the at least one vessel in intimate contact with the slurry and in an amount sufficient to oxidize or deactivate any carbonaceous and sulfidic mineral materials present in the ore and as the slurry is maintained at a temperature of about 70° F. to about 125° F.; agitating the slurry in a manner sufficient to permit the total amount of chlorine gas to become substantially completely adsorbed by the slurry in about 5 to about 15 minutes; maintaining the temperature of the slurry at between about 70° F. to about 125° F. for at least about 4 hours to allow the reaction mass to equilibrate with resulting passivation or alteration of the carbonaceous and sulfidic content of the ore so that it will not significantly sequester the gold content of the ore; and subjecting the ore to standard cyanidation treatment to recover an amount of gold therefrom.
Claim 25
Dependent Claim
44 words
The method of claim 21 wherein the slurry is agitated, with agitating means including a plurality of impeller blades that promotes contact between the chlorine gas and the liquid phase of the slurry so as to increase the mass transfer of the chlorine gas.
Claim 26
Dependent Claim
16 words
The method of claim 21 wherein slurry has a pH of about 2 to about 11.
Claim 27
Dependent Claim
60 words
The method of claim 23 which further comprises adding an acid to the slurry to reduce the pH of the slurry to within a range of about 2 to about 6 prior to introducing the chlorine gas into the vessel, to increase the rate at which the chlorine gas will react with the carbonaceous and pyritic constituents of the ore.
Claim 28
Dependent Claim
12 words
The method of claim 24 wherein the acid is a mineral acid.
Claim 29
Dependent Claim
15 words
The method of claim 25 wherein the mineral acid includes sulfuric, hydrochloric or nitric acid.
Claim 30
Dependent Claim
43 words
The method of claim 21 which further comprises dispersing an oxygen-containing gas through the slurry, prior to introducing the chlorine gas into the slurry, to provide an amount that exceeds that required for reaction with the carbonaceous and sulfidic constituents of the ore.
Claim 31
Dependent Claim
11 words
The method of claim 27 wherein the oxygen-containing gas is oxygen.
Claim 32
Dependent Claim
11 words
The method of claim 27 wherein the oxygen-containing gas is air.
Claim 33
Dependent Claim
19 words
The method of claim 21 wherein the slurry and the chlorine gas are introduced into a plurality of vessels.
Claim 34
Dependent Claim
17 words
The method of claim 30 wherein the slurry and the chlorine gas are introduced into four vessels.
Claim 35
Dependent Claim
44 words
The method of claim 21 wherein the ore contains from about 0.06 to about 1 or more ounces of gold per ton of ore, from about 0.1 to about 5% by weight of carbon and up to about 5% by weight of pyritic materials.
Claim 36
Dependent Claim
45 words
The method of claim 21 wherein the slurry is prepared by grinding the ore from about 50 to about 70 weight percent minus 200 mesh the ground ore with amount of water to form a slurry with about 40 to about 50% solids in water.
References Cited (Backward Citations)
US2552057A
Cited
US2918264A
Cited
US3290016A
Cited
US3360460A
Cited
US3846124A
Cited
US3930845A
Cited
US4188362A
Cited
US4038362A
Cited
US4193702A
Cited
US4289532A
Cited
US4259107A
Cited
US4444510A
Cited
US4353740A
Cited
US4439235A
Cited
JPS58197233A
Cited
US4401468A
Cited
JPS6021340A
Cited
JPS6059029A
Cited
US4551213A
Cited
JPS6137980A
Cited
US4578163A
Cited
US4723998A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-12-24 | 1994-06-25 | 1994-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-24 | 1998-06-25 | 1998-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-24 | 2002-06-25 | 2002-12-25 | $7700.00 | Window Closed / Lapsed |