System and Method for Leaching a Metal from a Base Mineral Rock

Abstract

A system and method for leaching a metal from a base mineral rock includes a closed reactor vessel into which a slurry containing the ground base mineral rock is fed. The interior space of the vessel is then pressurized via an oxygen supply to a pressure P. The slurry is then agitated under pressure P and within the closed reactor vessel for a time “t”. A blower or compressor re-circulates the oxygen through the slurry. The required pressure P and time “t” are effective for obtaining a metal recovery of up to 98% of the total metal available in the base mineral rock. Tests demonstrate that a time “t” in a range of 8 to 14 minutes and a pressure P of 10 to 50 psi is effective for obtaining the desired recovery amount, depending on the concentration of attacking agent used.

1 . A system for leaching gold, silver or other metals from a base mineral rock, the system comprising:
 a closed reactor vessel;   a slurry including a ground base mineral rock, a reagent and an attacking agent;   an oxygen supply in communication with an interior space of the closed reactor vessel; and   an agitator in communication with the slurry;   wherein the interior space of the closed reactor vessel is pressurized to a pressure “P” and the slurry is agitated under the pressure “P” and within the closed reactor vessel for a time “t”, pressure “P” and time “t” being effective for obtaining a metal recovery of up to 98% of the total metal available in the base mineral rock.   
   
   
       2 . A system according to  claim 1  further comprising the time “t” being in a range of 8 to 14 minutes. 
   
   
       3 . A system according to  claim 1  further comprising the pressure P being in a range of 10 to 50 psi. 
   
   
       4 . A system according to  claim 1  further comprising at least 90% of the base mineral rock being ground to a size under 80 mesh. 
   
   
       5 . A system according to  claim 1  further comprising the slurry being in a range of 20% to 50% solids by weight. 
   
   
       6 . A system according to  claim 1  further comprising a pH of the slurry being in a range of 10.5 to 11.5. 
   
   
       7 . A system according to  claim 1  further comprising a temperature of the slurry being in a range of 20° to 30° C. 
   
   
       8 . A system according to  claim 1  further comprising a concentration of the attacking agent in the slurry being in a range of 3 to 10 kg/m 3  of attacking solution. 
   
   
       9 . A system according to  claim 8  further comprising the attacking agent being a cyanide solution. 
   
   
       10 . A system according to  claim 1  further comprising the agitator including at least one of a blower and a compressor. 
   
   
       11 . A system according to  claim 10  further comprising the agitator including at least one of a recirculating piping and a jet. 
   
   
       12 . A method for leaching gold, silver or other metals from a base mineral rock, the method comprising the steps of:
 feeding a slurry into a closed reactor vessel, the slurry having a ground base mineral rock, a reagent and an attacking agent;   pressurizing, an interior space of the closed reactor vessel with oxygen to a pressure “P”;   maintaining the pressure “P”; and   agitating the slurry under pressure “P” and within the closed reactor vessel for a time “t”, pressure “P” and time “t” being effective for obtaining a metal recovery of up to 98% of the total metal available in the base mineral rock.   
   
   
       13 . A method according to  claim 12  further comprising the time “t” being in a range of 8 to 14 minutes. 
   
   
       14 . A method according to  claim 12  further comprising the pressure “P” being in a range of 10 to 50 psi. 
   
   
       15 . A method according to  claim 12  further comprising at least 90% of the base mineral rock being ground to a size under 80 mesh. 
   
   
       16 . A method according to  claim 12  further comprising the slurry being in range of 20% to 50% solids by weight. 
   
   
       17 . A method according to  claim 12  further comprising a pH of the slurry being in a range of 10.5 to 11.5. 
   
   
       18 . A method according to  claim 12  further comprising a temperature of the slurry being in a range of 20° to 30° C. 
   
   
       19 . A method according to  claim 12  further comprising a concentration of the attacking agent in the slurry being in a range of 3 to 10 kg/m 3  of attacking solution.