Method for froth flotation

Abstract

A process of separating a desired constituent from a mixture of particulate matter including the steps of: conditioning a liquid mixture of particulate matter with a frothing agent to create a pulp; aerating the pulp to generate a float fraction of froth supported on the surface of a non-float fraction of pulp; separating a portion of froth from the float fraction; draining the separated froth; washing the separated froth with a liquid to dislodge particles comprising one or more of non-selectively attached, entrained, and entrapped particles; and recovering the washed froth, is disclosed herein. Also disclosed herein are a froth cleaning apparatus and, a froth flotation apparatus for separating a desired constituent from a mixture of particulate matter. The froth cleaning apparatus includes a hood including a lower peripheral edge for interface with the top of a froth flotation cell; a discharge orifice disposed in the hood; a froth support in communication with the discharge outlet for receiving and supporting froth; and a wash sprayer disposed upstream of the discharge orifice. The flotation apparatus includes: a wall defining a flotation cell; an aerator for aerating a mixture of particulate matter to produce froth; a feed opening for introducing a mixture of particulate matter and/or froth into the cell; a discharge orifice in a wall of the cell; a froth support in communication with the discharge outlet for receiving and supporting the froth; and a wash sprayer disposed upstream of the discharge orifice.

1 . A process of separating a desired constituent from a mixture of particulate matter, comprising the steps of: 
 conditioning a liquid mixture of particulate matter comprising a desired constituent with a frothing agent to create a pulp;    aerating said pulp to generate a float fraction of froth supported on the surface of a non-float fraction of pulp, said float fraction comprising a plurality of bubbles, at least a portion of said bubbles selectively attached to said desired constituent of said pulp;    separating a portion of froth from said float fraction;    draining said separated froth;    washing said separated froth with a liquid to dislodge particles comprising one or more of non-selectively attached, entrained, and entrapped particles; and    recovering said washed froth;    wherein said draining step precedes said washing step.    
   
   
       2 . (canceled)  
   
   
       3 . The process of  claim 1 , wherein one or more of said separating step and said draining step comprises forcing said froth up an incline.  
   
   
       4 . The process of  claim 1 , wherein said desired component is coal.  
   
   
       5 . The process of  claim 1 , further comprising the step of conditioning one or more constituents of said mixture of particulate matter to render said constituent hydrophobic or more hydrophobic.  
   
   
       6 . The process of  claim 1 , wherein said aeration step comprises adding air to said pulp.  
   
   
       7 . The process of  claim 1 , wherein said liquid mixture of particulate matter is aqueous and said washing step comprises washing said separated froth with a component selected from water, a froth modifier, and combinations thereof.  
   
   
       8 . The process of  claim 1 , further comprising the step of substantially separating said wash liquid comprising dislodged particles from contact with separated froth.  
   
   
       9 . The process of  claim 8 , comprising the step of substantially separating said wash liquid comprising dislodged particles from contact with said washed froth.  
   
   
       10 . The process of  claim 1 , wherein the average particle size of said mixture is less than about 0.65 mm.  
   
   
       11 . The process of  claim 1 , further comprising the step of controlling the depth of said separated froth.  
   
   
       12 . The process of  claim 11 , wherein said controlling step comprises passing said separated froth through a passage having a controlled height.  
   
   
       13 .- 39 . (cancelled)  
   
   
       40 . The process of  claim 4 , wherein the average particle size of said coal is less than about 0.65 mm.  
   
   
       41 . The process of  claim 1 , further comprising draining said washed froth.  
   
   
       42 . The process of  claim 41 , wherein said draining of said washed froth is performed during and/or subsequent to said washing step.  
   
   
       43 . The process of  claim 1 , wherein said washing step comprises a plurality of washing operations performed in series.  
   
   
       44 . The process of  claim 1 , wherein said desired component is paper.  
   
   
       45 . The process of  claim 1 , wherein said desired component comprises a mineral.  
   
   
       46 . The process of  claim 1 , further comprising the step of controlling the level of said surface of non-float fraction of pulp.  
   
   
       47 . The process of  claim 46 , wherein said separating step comprises guiding said portion of froth up an upwardly-inclined surface and said controlling step comprises controlling the level of said surface of non-float fraction of pulp to intersect said upwardly-inclined surface.  
   
   
       48 . The process of  claim 1 , further comprising passing said separated froth through a screen.  
   
   
       49 . A process of separating a desired constituent from a mixture of particulate matter, comprising the steps of: 
 conditioning a liquid mixture of particulate matter comprising a desired constituent with a frothing agent to create a pulp;    aerating said pulp to generate a float fraction of froth supported on the surface of a non-float fraction of pulp, said float fraction comprising a plurality of bubbles, at least a portion of said bubbles selectively attached to said desired constituent of said pulp;    separating a portion of froth from said float fraction;    variably controlling the height of said separated froth at least at the point of separation;    draining said separated froth;    washing said separated froth with a liquid to dislodge particles comprising one or more of non-selectively attached, entrained, and entrapped particles; and    recovering said washed froth.