High temperature heap bioleaching process

Abstract

A heap is constructed with hypogenic copper sulfide bearing ore to include exposed sulfide mineral particles at least 25 weight % of which are hypogenic copper sulfides. The concentration of the exposed sulfide mineral particles is such that the heap includes at least 10 Kg of exposed sulfide sulfur per tonne of solids in the heap. At least 50% of the total copper in the heap is in the form of hypogenic copper sulfides. A substantial portion of the heap is heated to at least 50° C. The heap is inoculated with a thermophilic microorganism, and bioleaching is carried out so that sufficient sulfide mineral particles in the heap are biooxidized to oxidize at least 10 Kg of sulfide sulfur per tonne of solids in the heap and to cause the dissolution of at least 50% of the copper in the heap in a relatively short period of time.

1 . A high temperature heap bioleaching process, the process comprising the steps of:
 a. constructing a heap comprising chalcopyrite bearing ore, said heap including exposed sulfide mineral particles at least 25 weight % of which comprise chalcopyrite, wherein the concentration of exposed sulfide mineral particles in said heap is such that said heap contains at least 10 Kg of exposed sulfide sulfur per tonne of solids in said heap, and wherein at least 50% of the total copper in said heap is in the form of chalcopyrite;   b. heating a substantial portion of said heap to a temperature of at least 50° C.;   c. inoculating said heap with a culture comprising at least one thermophilic microorganism that biooxidizes sulfide minerals at a temperature above 50° C.;   d. irrigating said heap with a process leach solution comprising sulfuric acid and ferric iron; and   e. bioleaching sulfide mineral particles in said heap to thereby cause the dissolution of the sulfide mineral particles and generate heat, wherein sufficient sulfide minerals are oxidized in a bioleaching period of 210 days or less to oxidize at least 10 Kg of sulfide sulfur per tonne of solids in said heap and cause the dissolution of at least 50% of the copper in said heap into a process leach solution.   
     
     
         2 . A process according to  claim 1 , further comprising recovering copper from a pregnant process leach solution using a process selected from the group consisting of solvent extraction, ion exchange, and copper cementation. 
     
     
         3 . A process according to  claim 1 , further comprising recovering copper from a pregnant process leach solution using solvent extraction. 
     
     
         4 . A process according to  claim 1 , wherein said heap further comprises an insulating barrier layer on its surface. 
     
     
         5 . A process according to  claim 1 , wherein said heap is heated by flowing at least one heat source selected from the group consisting of steam, heated air, and heated aqueous solution through said heap. 
     
     
         6 . A high temperature heap bioleaching process, the process comprising the steps of:
 a. constructing a heap comprising chalcopyrite bearing ore, said heap including exposed sulfide mineral particles at least 25 weight % of which comprise chalcopyrite, wherein the concentration of exposed sulfide mineral particles in said heap is such that said heap contains at least 10 Kg of exposed sulfide sulfur per tonne of solids in said heap, and wherein at least 50% of the total copper in said heap is in the form of chalcopyrite;   b. heating a substantial portion of said heap to a temperature of at least 50° C.;   c. inoculating said heap with a culture comprising at least one thermophilic microorganism that biooxidizes sulfide minerals at a temperature above 50° C.;   d. bioleaching sulfide mineral particles in said heap to thereby cause the dissolution of the sulfide mineral particles and generate heat, wherein sufficient sulfide minerals are oxidized in a bioleaching period of 210 days or less to oxidize at least 10 Kg of sulfide sulfur per tonne of solids in said heap and cause the dissolution of at least 50% of the copper in said heap into a process leach solution; and   e. collecting pregnant process leach solution that contains dissolved copper as it drains from said heap.   
     
     
         7 . A process according to  claim 6 , further comprising recovering copper from a pregnant process leach solution using a process selected from the group consisting of solvent extraction, ion exchange, and copper cementation. 
     
     
         8 . A process according to  claim 6 , further comprising recovering copper from a pregnant process leach solution using solvent extraction. 
     
     
         9 . A process according to  claim 6 , wherein said heap further comprises an insulating barrier layer on its surface. 
     
     
         10 . A process according to  claim 6 , wherein said heap is heated by flowing at least one heat source selected from the group consisting of steam, heated air, and heated aqueous solution through said heap. 
     
     
         11 . A high temperature heap bioleaching process, the process comprising the steps of:
 a. constructing a heap comprising chalcopyrite bearing ore, said heap including exposed sulfide mineral particles at least 25 weight % of which comprise chalcopyrite, wherein the concentration of exposed sulfide mineral particles in said heap is such that said heap contains at least 10 Kg of exposed sulfide sulfur per tonne of solids in said heap, and wherein at least 50% of the total copper in said heap is in the form of chalcopyrite;   b. heating a substantial portion of said heap to a temperature of at least 50° C.;   c. inoculating said heap with a culture comprising at least one thermophilic microorganism that biooxidizes sulfide minerals at a temperature above 50° C.;   d. irrigating said heap with a process leach solution at a rate of at least 72 liters/m 2 /day; and   e. bioleaching sulfide mineral particles in said heap to thereby cause the dissolution of the sulfide mineral particles and generate heat, wherein sufficient sulfide minerals are oxidized in a bioleaching period of 210 days or less to oxidize at least 10 Kg of sulfide sulfur per tonne of solids in said heap and cause the dissolution of at least 50% of the copper in said heap into a process leach solution.   
     
     
         12 . A process according to  claim 11 , further comprising recovering copper from a pregnant process leach solution using a process selected from the group consisting of solvent extraction, ion exchange, and copper cementation. 
     
     
         13 . A process according to  claim 11 , further comprising recovering copper from a pregnant process leach solution using solvent extraction. 
     
     
         14 . A process according to  claim 11 , wherein said heap further comprises an insulating barrier layer on its surface. 
     
     
         15 . A process according to  claim 11 , wherein said heap is heated by flowing at least one heat source selected from the group consisting of steam, heated air, and heated aqueous solution through said heap.