Microbial pre-treatment of double refractory gold ores

Abstract

The present invention is directed to recovery of gold from refractory and double refractory ores using a fungal agent and/or culture media.

1 . A method, comprising:
 providing a refractory gold-containing feed material, the feed material comprising a preg robbing carbon-containing component;   inoculating the feed material with a fungal agent to passivate the preg robbing carbon-containing component, whereby at least most of the preg robbing ability of the carbon-containing component is deactivated; and   thereafter recovering the gold from the inoculated feed material.   
   
   
       2 . The method of  claim 1 , wherein the fungal agent is at least one of a white rot fungus and mutant thereof. 
   
   
       3 . The method of  claim 2 , wherein the fungal agent is at least one of a Coriolaceae cellular organism and a mutant thereof. 
   
   
       4 . The method of  claim 3 , wherein the fungal agent is at least one of a  Trametes  species and a mutant thereof. 
   
   
       5 . The method of  claim 1 , wherein the inoculating step occurs at a temperature of from about 15 to about 45° C. and a pH ranging from about pH 5 to about pH 10, wherein the feed material comprises from about 0.1 to about 5 oz/tonne gold, from about 0.3 to about 10 wt. % preg robbing carbon-containing component, and from about 0.1 to about 15 wt. % sulfidic sulfur, and further comprising:
 bio-oxidizing at least about 25% of the sulfidic sulfur in the feed material; and   after and/or during inoculation, contacting the feed material with nutrients for the fungal agent, the nutrients comprising a carbon source and one or more inducers to enhance production by the fungal agent of one or more selected enzymes to cause passivation of the feed material.   
   
   
       6 . A method, comprising:
 providing a refractory gold-containing feed material, the feed material comprising sulfidic sulfur;   inoculating the feed material with a fungal agent to decompose at least some of the sulfidic sulfur, whereby at least a portion of the gold is released from a sulfidic matrix; and   thereafter recovering the gold from the inoculated feed material.   
   
   
       7 . The method of  claim 6 , wherein the fungal agent is at least one of white rot fungus and a mutant thereof. 
   
   
       8 . The method of  claim 7 , wherein the feed material comprises a preg robbing carbon-containing component and wherein the fungal agent deactivates at least some of the preg robbing carbon-containing component. 
   
   
       9 . The method of  claim 8 , wherein the inoculating step occurs at a temperature of from about 15 to about 45° C. and a pH ranging from about pH 5 to about pH 10, wherein the feed material comprises from about 0.1 to about 5 oz/tonne gold, from about 0.3 to about 10 wt. % preg robbing carbon-containing component, and from about 0.1 to about 15 wt. % sulfidic sulfur, wherein at least about 25 wt. % of the sulfidic sulfur is decomposed by the fungal agent and further comprising:
 after and/or during inoculation, contacting the feed material with nutrients for the fungal agent, the nutrients comprising a carbon source and one or more inducers to enhance production by the fungal agent of one or more selected enzymes to cause decomposition of the sulfidic sulfur.   
   
   
       10 . The method of  claim 9 , wherein the nutrients comprise glucose, malt, and saccharomycetaceae. 
   
   
       11 . A method, comprising:
 providing a refractory gold-containing feed material, the feed material comprising sulfidic sulfur and a preg robbing carbon-containing component;   contacting the feed material with a culture media, in the substantial absence of a microbe, to decompose at least some of the sulfidic sulfur, whereby at least a portion of the gold is released from a sulfidic matrix;   thereafter inoculating the oxidized feed material with a microbial agent and the culture media to deactivate at least some of the preg robbing carbon containing component; and   thereafter recovering the gold from the inoculated feed material.   
   
   
       12 . The method of  claim 11 , wherein the microbial agent is selected from the group consisting essentially of white rot fungus,  Pseudomonas maltophilia, Pseudomonas oryzihabitans, Pseudomonas putida, Pseudomonas fluorescens, Pseudomonas stutzeri, Steptomyces setonii, Arthrobacter  species,  Achromobacter  species, and  Rhodococcus  species, and mutants and consortia thereof. 
   
   
       13 . The method of  claim 11 , wherein the fungal agent deactivates at least some of the preg robbing carbon-containing component. 
   
   
       14 . The method of  claim 13 , wherein the contacting step occurs at elevated temperature, wherein the inoculating step occurs at a temperature of from about 15 to about 45° C., wherein the contacting and inoculating steps occur at a pH ranging from about pH 5 to about pH 10, wherein the feed material comprises from about 0.1 to about 5 oz/tonne gold, from about 0.3 to about 10 wt. % preg robbing carbon-containing component, and from about 0.1 to about 15 wt. % sulfidic sulfur, wherein at least about 25 wt. % of the sulfidic sulfur is decomposed by the contacting step and wherein the culture media comprises a carbon source and one or more inducers to enhance production by the microbial agent of one or more selected enzymes to cause decomposition of the preg robbing carbonaceous component. 
   
   
       15 . The method of  claim 11 , wherein the culture media comprises glucose, malt, and saccharomycetaceae. 
   
   
       16 . A method, comprising:
 providing a refractory gold-containing feed material, the feed material comprising a preg robbing carbon-containing component;   inoculating the feed material with a fungal agent other than a Phanerochaete cellular organism to deactivate the preg robbing carbon-containing component, whereby at least most of the preg robbing ability of the carbon-containing component is deactivated; and   thereafter recovering the gold from the inoculated feed material.   
   
   
       17 . The method of  claim 16 , wherein the fungal agent is at least one of a white rot fungus and mutant thereof. 
   
   
       18 . The method of  claim 17 , wherein the fungal agent is at least one of a Coriolaceae cellular organism and a mutant thereof. 
   
   
       19 . The method of  claim 18 , wherein the fungal agent is at last one of a  Trametes  species and a mutant thereof. 
   
   
       20 . The method of  claim 16 , wherein the inoculating step occurs at a temperature of from about 15 to about 45° C. and a pH ranging from about pH 5 to about pH 10, wherein the feed material comprises from about 0.1 to about 5 oz/tonne gold, from about 0.3 to about 10 wt. % preg robbing carbon-containing component, and from about 0.1 to about 15 wt. % sulfidic sulfur, and further comprising:
 bio-oxidizing at least about 25% of the sulfidic sulfur in the feed material; and   after and/or during inoculation, contacting the feed material with nutrients for the fungal agent, the nutrients comprising a carbon source and one or more inducers to enhance production by the fungal agent of one or more selected enzymes to cause passivation of the feed material.