Leaching Copper-Containing Ores

Abstract

A method of leaching copper-containing ores includes leaching copper-containing ores or concentrates or tailings of the ores or concentrates with a leach liquor in the presence of an additive that enhances the dissolution of copper from copper minerals in the ores and concentrates by forming a complex between (a) sulfur, that has originated from copper minerals in the ores, and (b) the additive. A method of leaching copper-containing ores includes leaching copper-containing ores or concentrates or tailings of the ores or concentrates with a leach liquor includes leaching copper-containing ores or concentrates or tailings of the ores or concentrates with a leach liquor in the presence of a nitrogen-containing organic complexing additive that forms a complex between sulfur, that has originated from copper minerals in the ores, and the additive.

1 . A method of leaching copper-containing ores, such as copper-containing sulfidic ores such as sulfidic ores that contain copper minerals such as chalcopyrite and/or enargite, or concentrates of the ores or tailings of the ores or concentrates, that includes leaching copper-containing ores or concentrates or tailings of the ores or concentrates with a leach liquor in the presence of an additive that enhances the dissolution of copper from copper minerals in the ores and concentrates by forming a complex between (a) sulfur, that has originated from copper minerals in the ores, and (b) the additive. 
     
     
         2 . The method according to  claim 1 , wherein the complex comprises sulfur from the copper minerals and the additive, with the additive breaking down the passivating layer or reducing the formation of the layer and therefore allowing greater access for leaching copper from copper minerals during the method. 
     
     
         3 . The method according to  claim 1 , wherein the additive comprises a nitrogen-containing complexing agent that includes at least two nitrogen atoms spaced by two carbon atoms to permit the additive to form complexes between sulfur, that has originated from copper minerals in the ores, and the additive. 
     
     
         4 . The method according to  claim 1 , wherein the additive is a compound that contains the following molecular scaffold or a polymer that contains the molecular scaffold repeated through the polymer: 
       
         
           
           
               
               
           
         
         wherein, the two nitrogen atoms are each independently substituted or unsubstituted, each nitrogen atom is selected from the group consisting of a primary amine group, a secondary amine group, a tertiary amino group 
         the two carbon atoms may each be substituted or unsubstituted; 
         the bonds between the nitrogen atoms and carbon atoms in the scaffold may be single bonds or multiple bonds; and 
         the bonds between the two carbon atoms in the scaffold may be single bonds or multiple bonds. 
       
     
     
         5 . The method according to  claim 1 , wherein the additive is a compound of the formula (II) or a polymer formed from two of more monomers of the formula (II): 
       
         
           
           
               
               
           
         
         wherein, in formula (II) and (III), 
         R 1 , R 2 , R 3 , R 4 , R 5  and R 6  are each independently selected from a lone pair electron, H, alkyl groups (such as C 1  to C 5  alkyl groups), alkenyl groups (such as C 2  to C 5  alkenyl groups), alkynyl groups (such as C 2  to C 5  alkynyl groups), and alkylamino groups (such as C 1  to C 5  alkylamino groups), or the substituents on each of the two nitrogens together form an alkyl or alkynyl group that connect the two nitrogens to form a ring (e.g. the substituents together form a one or two carbon linker connecting the nitrogens to form a ring); 
         R 7 , R 8 , R 9  and R 10  are each independently selected from H, alkyl (such as C 1  to C 5  alkyl), alkenyl (such as C 2  to C 5  alkenyl), alkynyl (such as C 2  to C 5  alkynyl), OH, alkyloxy groups (such as C 1  to C 5  alkyloxy groups), alkenyloxy groups (such as C 2  to C 5  alkynyloxy groups), alkynyloxy groups (such as C 2  to C 5  alkynyloxy groups), C(═O)R (where R is alkyl, alkenyl or alkynyl), C(O)OH, C(O)OR (where R is alkyl, alkenyl or alkynyl), OC(═O)R (where R is alkyl, alkenyl or alkynyl), amino, alkylamino (such as C 1  to C 5  alkyl), alkenylamino (such as C 2  to C 5  alkenylamino), alkynylamino (such as C 2  to C 5  alkynylamino), C(O)NH 2 , C(O)NHR (where R is alkyl, alkenyl or alkynyl), C(O)NR 2  (where R is alkyl, alkenyl or alkynyl), or R 7  and R 8  together and/or R 9  and R 10  together may be selected from ═O, ═NH or ═NH (where R is alkyl, alkenyl or alkynyl); 
         and in formula (III), 
         R 1  or R 2  are each independently selected from the groups defined for R1 and R2 above or are connected to another monomer of formula (III). 
       
     
     
         6 . The method according to  claim 1 , wherein the concentration of the additive is up to 10 g/L, up to 5 g/L, up to 2.5 g/L, up to 1.5 g/L, up to 1.25 g/L, or up to 1 g/L, in the leach liquor. 
     
     
         7 . The method according to  claim 1 , wherein leaching includes controlling the temperature to be less than 100° C., less than 65° C., less than 60° C., less than 55° C., or less than 50° C. 
     
     
         8 . The method according to  claim 1 , wherein leaching includes controlling the leach temperature to be at least 5° C., at least 20° C., at least 30° C., or at least 50° C. 
     
     
         9 . The method according to  claim 1 , wherein leaching includes controlling the oxidation potential of the leach liquor during an active leaching phase to be less than 900 mV, less than 800 mV, in a range of 500 to 800 mV, or in a range of 600 to 750 mV, wherein the oxidation potential is determined with respect to the standard hydrogen electrode. 
     
     
         10 . The method according to  claim 1 , wherein leaching includes controlling the pH of the leach liquor to be less than 2.5, less than 2.0, less than 1.8, or less than 1.5. 
     
     
         11 . The method according to  claim 1 , wherein leaching includes controlling the pH of the leach liquor to be greater than 0.5, or greater than 1. 
     
     
         12 . The method according to  claim 1 , wherein leaching includes bioleaching with microorganisms to assist leaching of copper. 
     
     
         13 . The method according to  claim 1 , wherein leaching includes adding chemical oxidants, such as O 2 /SO 2 , pyrolusite, permanganate ions, ferric ions, peroxide ions, and chlorate ions, to the leach liquor. 
     
     
         14 . The method according to  claim 1 , includes recovering copper from the leach liquor in downstream copper recovery steps. 
     
     
         15 . The method according to  claim 1 , includes adding the additive to the leach liquor continuously or periodically during the method to maintain a required concentration during the method. 
     
     
         16 . The method according to  claim 1 , includes adding the additive to ore fragments prior to the leaching step. 
     
     
         17 . The method according to  claim 16 , includes forming agglomerates of ore fragments and adding the additive to agglomerates prior to the leaching step. 
     
     
         18 . The method according to  claim 16 , includes forming agglomerates of ore fragments and adding the additive while forming agglomerates. 
     
     
         19 . The method according to  claim 16 , wherein the additive is polyethylenimine (PEI) or another polymer-like additive, such as longer chain organic substances, the agglomeration step includes:
 (a) forming a PEI solution having a pH greater than pH 4.5;   (b) optionally heating the solution to at least 50° C. to speed up the dissolution/dilution of the PEI; and   (c) adding the PEI solution to ore fragments at the start of the agglomeration step, for example before other additions in the agglomeration step.   
     
     
         20 . The method according to  claim 1 , includes regenerating the leach liquor and recycling the regenerated leach liquor to the heap. 
     
     
         21 . The method according to  claim 20 , includes adjusting the concentration of the additive in the regenerated leach liquor to maintain a concentration of up to 10 g/L, up to 5 g/L, up to 2.5 g/L, up to 1.5 g/L, up to 1.25 g/L, or up to 1 g/L, in the leach liquor. 
     
     
         22 . The method according to  claim 20 , includes adding the additive to the regenerated leach liquor to maintain a concentration of up to 10 g/L, up to 5 g/L, up to 2.5 g/L, up to 1.5 g/L, up to 1.25 g/L, or up to 1 g/L, in the leach liquor. 
     
     
         23 . The method according to  claim 20 , includes removing the additive from the regenerated leach liquor to maintain a concentration of up to 10 g/L, up to 5 g/L, up to 2.5 g/L, up to 1.5 g/L, up to 1.25 g/L, or up to 1 g/L, in the leach liquor. 
     
     
         24 . A method of leaching copper-containing ores, such as copper-containing sulfidic ores such as sulfidic ores that contain copper minerals such as chalcopyrite and/or enargite, or concentrates of the ores or tailings of the ores or concentrates, that includes leaching copper-containing ores or concentrates or tailings of the ores or concentrates with a leach liquor in the presence of a nitrogen-containing organic complexing additive that forms a complex between sulfur, that has originated from copper minerals in the ores, and the additive. 
     
     
         25 . The method defined in  claim 24 , wherein the complex comprises sulfur in a passivating layer on copper minerals and the additive, with the complex breaking down the passivating layer or reducing the formation of the layer and therefore allowing greater access for leaching copper from copper minerals during the method. 
     
     
         26 . The method defined in  claim 24 , wherein the additive is a degradation product that forms under the conditions of the leach and is an effective additive in the terms of the invention. 
     
     
         27 . The method defined in  claim 26 , wherein the degradation product is a degradation product of another said additive. 
     
     
         28 . The method defined in  claim 24 , wherein the nitrogen-containing complexing agent includes at least two nitrogen atoms. 
     
     
         29 . The method defined in  claim 28  wherein each of the at least two nitrogen atoms in the additive is present as a primary amine group, a secondary amine group or a tertiary amine group. 
     
     
         30 . The method defined in  claim 24  wherein the nitrogen-containing complexing agent includes at least two nitrogen atoms spaced by two carbon atoms to permit the additive to form the complex. 
     
     
         31 . The method defined in  claim 24  wherein the additive is a compound that contains the following molecular scaffold or a polymer that contains the molecular scaffold repeated through the polymer: 
       
         
           
           
               
               
           
         
         wherein, the two nitrogen atoms are each independently substituted or unsubstituted, each nitrogen atom is selected from the group consisting of a primary amine group, a secondary amine group, a tertiary amino group 
         the two carbon atoms may each be substituted or unsubstituted; 
         the bonds between the nitrogen atoms and carbon atoms in the scaffold may be single bonds or multiple bonds; and 
         the bonds between the two carbon atoms in the scaffold may be single bonds or multiple bonds; 
         or 
         the additive is a compound of the formula (II) or a polymer formed from two of more monomers of the formula (II): 
       
       
         
           
           
               
               
           
         
         wherein, in formula (II) and (III), 
         R 1 , R 2 , R 3 , R 4 , R 5  and R 6  are each independently selected from a lone pair electron, H, alkyl groups (such as C 1  to C 5  alkyl groups), alkenyl groups (such as C 2  to C 5  alkenyl groups), alkynyl groups (such as C 2  to C 5  alkynyl groups), and alkylamino groups (such as C 1  to C 5  alkylamino groups), or the substituents on each of the two nitrogens together form an alkyl or alkynyl group that connect the two nitrogens to form a ring (e.g. the substituents together form a one or two carbon linker connecting the nitrogens to form a ring); 
         R 7 , R 8 , R 9  and R 10  are each independently selected from H, alkyl (such as C 1  to C 5  alkyl), alkenyl (such as C 2  to C5 alkenyl), alkynyl (such as C 2  to C 5  alkynyl), OH, alkyloxy groups (such as C 1  to C 5  alkyloxy groups), alkenyloxy groups (such as C 2  to C 5  alkynyloxy groups), alkynyloxy groups (such as C 2  to C 5  alkynyloxy groups), C(═O)R (where R is alkyl, alkenyl or alkynyl), C(O)OH, C(O)OR (where R is alkyl, alkenyl or alkynyl), OC(═O)R (where R is alkyl, alkenyl or alkynyl), amino, alkylamino (such as C 1  to C 5  alkyl), alkenylamino (such as C 2  to C 5  alkenylamino), alkynylamino (such as C 2  to C 5  alkynylamino), C(O)NH 2 , C(O)NHR (where R is alkyl, alkenyl or alkynyl), C(O)NR 2  (where R is alkyl, alkenyl or alkynyl), or R 7  and R 8  together and/or R 9  and R 10  together may be selected from ═O, ═NH or ═NH (where R is alkyl, alkenyl or alkynyl); 
         and in formula (III), 
         R 1  or R 2  are each independently selected from the groups defined for R1 and R2 above or are connected to another monomer of formula (III).