Processes for recovering metals from ores using organic solvent extraction and aqueous stripping at selected temperature differentials

Abstract

The disclosed invention concerns a process comprising: (a) providing a pregnant leach solution comprising copper values; (b) contacting the pregnant leach solution with an organic phase comprising a copper extractant at an extraction temperature, T ext , to form a loaded organic phase comprising the metal values; (c) contacting the loaded organic phase with an aqueous stripping solution at a stripping temperature, T strip , to form a copper-enriched stripping solution; wherein the difference in temperature (ΔT) between the stripping temperature and the extraction temperature according to equation (I): ΔT=T strip −T ext is less than or equal to about 10° C. In other increasingly more preferred embodiments of the invention, the difference in temperature (ΔT) is less than or equal to about 5° C., less than or equal to about 2.5° C., less than or equal to about 0° C., less than or equal to about −5° C., and less than or equal to about −10° C. Also disclosed are economic means to manipulate the extraction, strip, and electrowinning temperatures to achieve these temperature differentials.

1 . A copper recovery process comprising: 
 (a) providing a pregnant leach solution comprising copper values;    (b) contacting the pregnant leach solution with an organic phase comprising a copper extractant at an extraction temperature, T ext , to form a loaded organic phase comprising the copper values;    (c) contacting the resulting loaded organic phase with an aqueous stripping solution at a stripping temperature, T strip , to form a copper-enriched stripping solution;    wherein the difference in temperature (ΔT) between the stripping temperature and the extraction temperature according to equation (I):        ΔT=T   strip   −T   ext   (I)    is less than or equal to about 10° C.    
   
   
       2 . The copper recovery process according to  claim 1 , wherein the difference in temperature (ΔT) is less than or equal to about 7.5° C.  
   
   
       3 . The copper recovery process according to  claim 1 , wherein the difference in temperature (ΔT) is less than or equal to about 5° C.  
   
   
       4 . The copper recovery process according to  claim 1 , wherein the difference in temperature (ΔT) is less than or equal to about 2.5° C.  
   
   
       5 . The copper recovery process according to  claim 1 , wherein the difference in temperature (ΔT) is less than or equal to about 0° C.  
   
   
       6 . The copper recovery process according to  claim 1 , wherein the difference in temperature (ΔT) is less than or equal to about −2.5° C.  
   
   
       7 . The copper recovery process according to  claim 1 , wherein the difference in temperature (ΔT) is less than or equal to about −5° C.  
   
   
       8 . The copper recovery process according to  claim 1 , wherein the difference in temperature (ΔT) is less than or equal to about −7.5° C.  
   
   
       9 . The copper recovery process according to  claim 1 , wherein the difference in temperature (ΔT) is less than or equal to about −10° C.  
   
   
       10 . The copper recovery process according to  claim 1 , wherein one of more heat exchangers are utilized to lower the stripping temperature of the aqueous stripping solution.  
   
   
       11 . The copper recovery process according to  claim 10 , wherein the one or more heat exchangers transfer heat from a lean electrolyte exiting an electrowinning stage to the copper-enriched stripping solution such that a cooled lean electrolyte is formed and the cooled lean electrolyte is used as at least a portion of the aqueous stripping solution.  
   
   
       12 . The copper recovery process according to  claim 10 , wherein the one or more heat exchangers transfer heat from a lean electrolyte exiting an electrowinning stage to a water source such that a cooled lean electrolyte is formed and the cooled lean electrolyte is used as at least a portion of the aqueous stripping solution.  
   
   
       13 . The copper recovery process according to  claim 1 , wherein one or more heat exchangers are utilized to raise the extraction temperature of the pregnant leach solution.  
   
   
       14 . The copper recovery process according to  claim 13 , wherein the one or more heat exchangers transfer heat from a lean electrolyte exiting an electrowinning stage to the pregnant leach solution.  
   
   
       15 . The copper recovery process according to  claim 12 , wherein the one or more heat exchangers transfer heat from a heat source selected from the group consisting of boilers and waste heat gases to the pregnant leach solution.  
   
   
       16 . A copper recovery process comprising: 
 (a) providing a pregnant leach solution comprising copper values;    (b) contacting the pregnant leach solution with an organic phase comprising a copper extractant at an extraction temperature, T ext , to form a loaded organic phase comprising the copper values;    (c) contacting the resulting loaded organic phase with an aqueous stripping solution at a stripping temperature, T strip , to form a copper-enriched stripping solution;    wherein the difference in temperature (ΔT) between the stripping temperature and the extraction temperature according to equation (I):        ΔT=T   strip   −T   ext   (I)    is less than or equal to about 10° C.,    wherein one or more heat exchangers are utilized to lower the stripping temperature of the aqueous stripping solution.    
   
   
       17 . The copper recovery process according to  claim 16 , wherein the difference in temperature (ΔT) is less than or equal to about −2.5° C.  
   
   
       18 . The copper recovery process according to  claim 16 , wherein the one or more heat exchangers transfer heat from a lean electrolyte exiting an electrowinning stage to the copper-enriched stripping solution such that a cooled lean electrolyte is formed and the cooled lean electrolyte is used as at least a portion of the aqueous stripping solution.  
   
   
       19 . The copper recovery process according to  claim 16 , wherein the one or more heat exchangers transfer heat from a lean electrolyte exiting an electrowinning stage to a water source such that a cooled lean electrolyte is formed and the cooled lean electrolyte is used as at least a portion of the aqueous stripping solution.  
   
   
       20 . A copper recovery process comprising: 
 (a) providing a pregnant leach solution comprising copper values;    (b) contacting the pregnant leach solution with an organic phase comprising a copper extractant at an extraction temperature, T ext , to form a loaded organic phase comprising the copper values;    (c) contacting the resulting loaded organic phase with an aqueous stripping solution at a stripping temperature, T strip , to form a copper-enriched stripping solution;    wherein the difference in temperature (ΔT) between the stripping temperature and the extraction temperature according to equation (I):        ΔT=T   strip   −T   ext   (I)    is less than or equal to about 10° C.,    wherein one or more heat exchangers are utilized to raise the extraction temperature of the pregnant leach solution.    
   
   
       21 . The copper recovery process according to  claim 20 , wherein the difference in temperature (ΔT) is less than or equal to about −2.5° C.  
   
   
       22 . The copper recovery process according to  claim 20 , wherein the one or more heat exchangers transfer heat from a lean electrolyte exiting an electrowinning stage to the pregnant leach solution.  
   
   
       23 . The copper recovery process according to  claim 20 , wherein the one or more heat exchangers transfer heat from a heat source selected from the group consisting of boilers and waste heat gases to the pregnant leach solution.