System and Method for Removing Organics from Phosphate Ore Using an Acid

Abstract

This disclosure describes methods, processes and devices that remove or release organics from ores, such as phosphate ores or secondary sources such as mine tailings or waste. The method comprises: preparing an ore to a pre-set size; mixing the ore with an acidic reagent having an initial pH value in a slurry comprising the ore and the reagent; and while mixing the slurry, maintaining a pH level in the slurry to a pH range. While mixing the slurry, the slurry may produce a supernatant containing organic material removed from the ore and sediment containing refined ore. The method may also screen the slurry to create a first stream of materials that does not pass through the screen and a second stream of materials and refined ore that pass through the screen.

1 . A method for removing or releasing organics from ores, comprising:
 preparing an ore to a size of approximately 4 mm or less;   mixing the ore with a reagent comprising sulfuric acid and having an initial pH value in a slurry comprising the ore and the reagent;   separating the slurry into a first stream of materials and a second stream of smaller materials separated from first stream of materials, the second stream comprising refined ore, using a screen having a screen size of between approximately 1.0 mm and 0.6 mm to create the first stream of materials that does not pass through the screen and the second stream of smaller materials that passes through the screen; and   while mixing the slurry, maintaining a pH level in the slurry to a pH range.   
     
     
         2 . The method for removing organics from ores as claimed in  claim 1 , wherein while mixing the slurry:
 a supernatant containing organic material is produced, which is removed from the ore; and   sediment containing refined ore is produced.   
     
     
         3 . The method for removing organics from ores as claimed in  claim 2 , wherein:
 the slurry is mixed using an attrition scrubbing device.   
     
     
         4 . The method for removing organics from ores as claimed in  claim 3 , wherein:
 the ore is a phosphate ore.   
     
     
         5 . The method for removing organics from ores as claimed in  claim 4 , wherein:
 the pH range is between approximately pH 2.0 and 4.5.   
     
     
         6 . The method for removing organics from ores as claimed in  claim 5 , further comprising:
 mixing the slurry until a stop condition for the ore is reached, the stop condition being any one or more of a pre-set time, detection of a change in viscosity in the slurry, or detection of a change of particle size in the slurry.   
     
     
         7 . The method for removing organics from ores as claimed in  claim 1 , further comprising:
 screening the second stream through a second screen; and   removing the refined ore from material that passes through the second screen.   
     
     
         8 . The method for removing organics from ores as claimed in  claim 7 , further comprising:
 treating the second stream to froth flotation to separate the refined ore from gangue minerals therein.   
     
     
         9 . The method for removing organics from ores as claimed in  claim 4 , wherein:
 the initial pH value is set at a threshold level that is sufficiently high to not cause dissolving of substantial quantities of apatite in the slurry.   
     
     
         10 . The method for removing organics from ores as claimed in  claim 9 , further comprising:
 mixing the slurry until a stop condition for the ore is reached, the stop condition being any one or more of a pre-set time, detection of a change in viscosity in the slurry, or detection of a change of particle size in the slurry.   
     
     
         11 . The method for removing organics from ores as claimed in  claim 1 , further comprising:
 grinding ore in the first stream producing ground ore; and   feeding the ground ore to slurry for further conditioning.   
     
     
         12 . The method for removing organics from ores as claimed in  claim 1 , further comprising:
 screening the second stream of smaller materials to remove high-grade size fractions of refined ore therefrom.   
     
     
         13 . A process for removing organics from phosphate ores crushed to a particle size of 4.0 mm or less, the process comprising:
 conditioning a phosphate ore with a reagent to produce a slurry, the reagent comprising sulfuric acid, and the reagent having an initial pH value between approximately pH 2.0 and 4.5;   mixing the slurry in an attrition scrubbing device, where the slurry produces a supernatant containing organic material removed from the phosphate ore and sediment containing refined phosphate ore;   separating the slurry into a first stream of materials and a second stream of smaller materials, the second stream comprising refined phosphate ore, using a screen having a screen size of between approximately 1.0 mm and 0.6 mm to create the first stream of materials that does not pass through the screen and the second stream of smaller materials that passes through the screen;   grinding the phosphate ore in the first stream producing ground ore;   mixing the ground ore into the slurry for further conditioning;   maintaining a pH level in the slurry to a pH range;   removing the refined phosphate ore from the second stream; and   after removing the refined phosphate ore, treating the second stream to flotation to separate remaining refined phosphate ore from gangue minerals therein.   
     
     
         14 . The process for removing organics from phosphate ores as claimed in  claim 13 , further comprising:
 screening the second stream to remove high-grade size fraction of refined ore therefrom.   
     
     
         15 . The process for removing organics from phosphate ores as claimed in  claim 13 , further comprising:
 mixing the slurry until a stop condition for the ore is reached, the stop condition being any one or more of a pre-set time, detection of a change in viscosity in the slurry, or detection of a change of particle size in the slurry.   
     
     
         16 . A method for removing or releasing organics from phosphate ore, where the phosphate ore has been prepared to a size of approximately 4 mm or less, the method comprising:
 mixing the phosphate ore with an acidic reagent in a slurry comprising the phosphate ore and the acidic reagent;   mixing the slurry in an attrition scrubbing device while maintaining a pH level in the slurry to a pH range; and
 removing a supernatant containing organic material to produce sediment containing refined phosphate ore; 
 and 
   using a screen having a screen size of between approximately 1.0 mm and 0.6 mm to separate the slurry to create a first stream of materials and a second stream of smaller materials, the second stream comprising refined ore and the refined ore having a size of approximately 1.0 mm or less; and   stop mixing the slurry after detection in the slurry of a change in viscosity or a change of particle size.   
     
     
         17 . The method for removing organics from a phosphate ore as claimed in  claim 16 , wherein:
 the pH range is between approximately pH 2.0 and 4.5; and   the reagent comprises sulfuric acid.   
     
     
         18 . The method for removing organics from an ore as claimed in  claim 17 , further comprising:
 screening the second stream of smaller materials through a second screen; and   removing the refined ore from material that passes through the second screen.   
     
     
         19 . The method for removing organics from a phosphate ore as claimed in  claim 16 , wherein:
 the initial pH value is set at a threshold level that is sufficiently high to not cause dissolving of substantial quantities of apatite in the slurry.