Apparatus and method for efficient particle to gas bubble attachment in a slurry

Abstract

The present invention relates to an apparatus and a process for efficient hydrophobic particles to gas bubble attachment in a slurry is provided. The process comprises: tangentially introducing a slurry stream into a cylindrical chamber having a cylindrical inner wall with sufficient volume and pressure to develop a vortex in the flowing slurry; introducing gas into the flowing slurry during at least a portion of its travel in the chamber, the gas being introduced orthogonally to the stream through means located at the chamber inner wall and for developing gas bubbles which move into the slurry. The apparatus comprises of: a cylindrical chamber having a cylindrical inner wall, the chamber being oriented in any direction, enclosed at both ends, and with an entry port to introduce the stream of slurry to develop a spiral flow of the stream along the chamber inner wall toward the output end, a porous wall to permit the introduction of gas orthogonally into the stream to develop gas bubbles within the stream, and an exit port to discharge the mixture of slurry and gas bubbles.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
         1 . A process for attaching hydrophobic particles to gas bubble in a slurry said process comprising:
 i) introducing a stream of said slurry into a vessel having a cylindrical chamber having a cylindrical inner wall, said chamber being oriented in any direction and enclosed at both ends, said stream being introduced tangentially near a first end of said chamber, the entry end, in a manner to develop a spiral flow of said stream along said chamber inner wall toward the opposite, second end of said chamber, the exit end;   ii) introducing said stream in sufficient volume and pressure to develop a vortex in said stream extending along said chamber;   iii) introducing gas into said stream during at least a portion of its travel in said chamber, said gas being introduced to said stream orthogonally, through means located at said chamber inner wall for developing gas bubbles which move into said stream;   iv) said chamber being of sufficient length to provide a residence time for said stream in said chamber to permit a diffusion of gas into said stream; and   v) discharging said stream of slurry with gas bubbles to exit the vessel at the exit end.   
     
     
         2 . A process for entrainment of hydrophobic particles with gas bubbles in a mixture of water and insoluble liquid or liquids, said process comprising:
 i) introducing a stream of said mixture into a vessel having a cylindrical chamber having a cylindrical inner wall, said chamber being oriented in any direction and enclosed at both ends, said stream being introduced tangentially near a first end of said chamber, the entry end, in a manner to develop a spiral flow of said stream along said chamber inner wall toward the opposite, second end of said chamber, the exit end;   ii) introducing said stream in sufficient volume and pressure to develop a vortex in said stream extending along said chamber;   iii) introducing gas into said stream during at least a portion of its travel in said chamber, said gas being introduced to said stream orthogonally, through means located at said chamber inner wall for developing gas bubbles which move into said stream;   iv) said chamber being of sufficient length to provide a residence time in said chamber to permit entrainment of particles with gas bubbles in said steam; and   v) discharging said stream with gas bubbles to exit the vessel at the exit end.   
     
     
         3 . A process for separation of hydrophobic particles from slurry by attaching hydrophobic particles to gas bubble in a slurry said process comprising:
 i) introducing a stream of said slurry into a vessel having a cylindrical chamber having a cylindrical inner wall, said chamber being oriented in any direction and enclosed at both ends, said stream being introduced tangentially near a first end of said chamber, the entry end, in a manner to develop a spiral flow of said stream along said chamber inner wall toward the opposite, second end of said chamber, the exit end;   ii) introducing said stream in sufficient volume and pressure to develop a vortex in said stream extending along said chamber;   iii) introducing gas into said stream during at least a portion of its travel in said chamber, said gas being introduced to said stream orthogonally, through means located at said chamber inner wall for developing gas bubbles which move into said stream;   iv) said chamber being of sufficient length to provide a residence time for said stream in said chamber to permit a diffusion of gas into said stream;   v) discharging said stream with hydrophobic particles attached to gas bubbles at said exit end into a catch basin surrounding said exit end, said stream swirling outwardly as said stream flows into said catch basin having a liquid level proximate said exit end to permit said gas bubbles to float toward a peripheral edge of said catch basin; and   vi) separating gas bubbles with said attached hydrophobic particles from heavier particles by collecting outwardly said floating gas bubbles with attached hydrophobic particles with an upper zone of said catch basin, while heavier particles sink downwardly of said catch basin, and removing heavier particles from a lower zone of said catch basin to effect separation.   
     
     
         4 . A process for separation of hydrophobic particles from mixture of water and insoluble liquid or liquids by entrainment of hydrophobic particles with gas bubbles in a mixture of water and insoluble liquid or liquids, said process comprising:
 i) introducing a stream of said mixture into a vessel having a cylindrical chamber having a cylindrical inner wall, said chamber being oriented in any direction and enclosed at both ends, said stream being introduced tangentially near a first end of said chamber, the entry end, in a manner to develop a spiral flow of said stream along said chamber inner wall toward the opposite, second end of said chamber, the exit end;   ii) introducing said stream in sufficient volume and pressure to develop a vortex in said stream extending along said chamber;   iii) introducing gas into said stream during at least a portion of its travel in said chamber, said gas being introduced to said stream orthogonally, through means located at said chamber inner wall for developing gas bubbles which move into said stream;   iv) said chamber being of sufficient length to provide a residence time in said chamber to permit entrainment of particles with gas bubbles in said steam;   v) discharging said stream with hydrophobic particles attached to gas bubbles at said exit end into a catch basin surrounding said exit end, said stream swirling outwardly as said stream flows into said catch basin having a liquid level proximate said exit end to permit said gas bubbles to float toward a peripheral edge of said catch basin; and   vi) separating gas bubbles with said attached hydrophobic particles from heavier particles by collecting outwardly said floating gas bubbles with attached hydrophobic particles with an upper zone of said catch basin, while heavier particles sink downwardly of said catch basin, and removing heavier particles from a lower zone of said catch basin to effect separation.   
     
     
         5 . A process according to  claim 1  or  2  or  3  or  4 , wherein said means located at said chamber inner wall for developing gas bubbles consists of a porous wall forming at least a portion of said chamber inner wall. 
     
     
         6 . A process according to  claim 1 ,  2 ,  3  or  4 , wherein said means located at said chamber inner wall for developing gas bubbles consists of material having porosity with mean pore size of no greater than 100 microns. 
     
     
         7 . A process according to  claim 5 , wherein said porous wall consists of material having porosity with mean pore size of no greater than 100 microns. 
     
     
         8 . A process according to  claim 1  or  2  or  3  or  4  or  5  or  6  or  7 , wherein said stream is introduced in sufficient volume and pressure to develop a vortex in said stream extending along said chamber generally from end to end. 
     
     
         9 . A process according to  claim 8 , wherein the velocity of said stream is set to achieve centrifugal forces for said vortex to within a range of 20 to 100 G's. 
     
     
         10 . An apparatus for hydrophobic particles and gas bubble attachment in a slurry, said apparatus comprising:
 i) a cylindrical chamber having a cylindrical inner wall, said chamber being oriented in any direction, and enclosed at both ends;   ii) means for introducing a stream of slurry tangentially of said inner wall, said stream introducing means being positioned in an input zone of said chamber to direct said stream in a manner to develop a spiral flow of said stream along said inner wall toward the opposite end;   iii) at least one gas entry port, for introducing gas into said inner chamber through means located along at least a portion of said chamber inner wall and extending at least in part there around, for introducing gas orthogonally into said inner chamber as said stream passes over said gas introduction means;   iv) said chamber being of sufficient length to provide a residence time for said stream in said chamber to permit a diffusion of gas into said stream; and   v) means to discharge said stream with hydrophobic particles attached to gas bubbles into receiving means, said receiving means being positioned in a discharge zone of said chamber to direct said stream of outside of said vessel.   
     
     
         11 . An apparatus for hydrophobic particles entrainment with gas bubbles in a mixture of water and insoluble liquid or liquids, said apparatus comprising:
 i) a vessel consisting of a cylindrical tube defining an interior cylindrical chamber with a cylindrical inner wall, and with enclosed ends;   ii) means for introducing a stream of a mixture of water and insoluble liquid or liquids tangentially of said inner wall, said stream introducing means being positioned in an input zone of said chamber to direct said stream in a manner, to develop a spiral flow of said stream along said inner wall toward the opposite end;   iii) at least one gas entry port, for introducing gas into said inner chamber through means located along at least a portion of said chamber inner wall and extending at least in part there around, for introducing gas orthogonally into said inner chamber as said stream passes over said gas introduction means;   iv) said chamber being of sufficient length to provide a residence time for said stream in said chamber to permit a diffusion of gas into said stream; and   iv) means to discharge said stream with hydrophobic particles attached to gas bubbles into receiving means, said receiving means being positioned in a discharge zone of said chamber to direct said stream outside of said vessel.   
     
     
         12 . An apparatus for separation of hydrophobic particles from slurry through hydrophobic particles and gas bubble attachment in a slurry, said apparatus comprising:
 i) a cylindrical chamber having a cylindrical inner wall, said chamber being oriented in any direction, and enclosed at both ends,   ii) means for introducing a stream of slurry tangentially of said inner wall, said stream introducing means being positioned in an input zone of said chamber to direct said stream in a manner to develop a spiral flow of said stream along said inner wall toward the opposite end,   iii) at least one gas entry port, for introducing gas into said inner chamber through means located along at least a portion of said chamber inner wall and extending at least in part there around, for introducing gas orthogonally into said inner chamber as said stream passes over said gas introduction means;   iv) said chamber being of sufficient length to provide a residence time for said stream in said chamber to permit a diffusion of gas into said stream;   vi) means to discharge said stream with hydrophobic particles attached to gas bubbles at said exit end into a catch basin surrounding said exit end, said stream swirling outwardly as said stream flows into said catch basin having a liquid level proximate said exit end to permit said gas bubbles with said attached hydrophobic particles to float toward a peripheral edge of said catch basin; and   vii) separating gas bubbles with said attached hydrophobic particles from heavier particles by collecting outwardly said floating gas bubbles with attached hydrophobic particles with an upper zone of said catch basin, while heavier particles sink downwardly of said catch basin, and removing heavier particles from a lower zone of said catch basin to effect separation.   
     
     
         13 . An apparatus for separation of hydrophobic particles from mixture of water and insoluble liquid or liquids through hydrophobic particles entrainment with gas bubbles in a mixture of water and insoluble liquid or liquids, said apparatus comprising:
 i) a vessel consisting of a cylindrical tube defining an interior cylindrical chamber with a cylindrical inner wall, and with enclosed ends,   ii) means for introducing a stream of a mixture of water and insoluble liquid or liquids tangentially of said inner wall, said stream introducing means being positioned in an input zone of said chamber to direct said stream in a manner, to develop a spiral flow of said stream along said inner wall toward the opposite end,   iii) at least one gas entry port, for introducing gas into said inner chamber through means located along at least a portion of said chamber inner wall and extending at least in part there around, for introducing gas orthogonally into said inner chamber as said stream passes over said gas introduction means;   iv) said chamber being of sufficient length to provide a residence time for said stream in said chamber to permit a diffusion of gas into said stream,   vi) means to discharge said stream with hydrophobic particles attached to gas bubbles at said exit end into a catch basin surrounding said exit end, said stream swirling outwardly as said stream flows into said catch basin having a liquid level proximate said exit end to permit said gas bubbles to float toward a peripheral edge of said catch basin; and   vii) means to separate gas bubbles with said attached hydrophobic particles from heavier particles by collecting outwardly said floating gas bubbles with attached hydrophobic particles with an upper zone of said catch basin, while heavier particles sink downwardly of said catch basin, and removing heavier particles from a lower zone of said catch basin to effect separation.   
     
     
         14 . An apparatus, for new flotation systems and retrofitting to existing flotation systems, for separation of hydrophobic particles from slurry through hydrophobic particles and gas bubble attachment in a slurry, said apparatus comprising:
 i) a cylindrical chamber having a cylindrical inner wall, said chamber being oriented in any direction, and enclosed at both ends,   ii) means for introducing a stream of slurry tangentially of said inner wall, said stream introducing means being positioned in an input zone of said chamber to direct said stream in a manner to develop a spiral flow of said stream along said inner wall toward the opposite end,   iii) at least one gas entry port, for introducing gas into said inner chamber through means located along at least a portion of said chamber inner wall and extending at least in part there around, for introducing gas orthogonally into said inner chamber as said stream passes over said gas introduction means;   iv) said chamber being of sufficient length to provide a residence time for said stream in said chamber to permit a diffusion of gas into said stream;   vi) means to discharge said stream with hydrophobic particles attached to gas bubbles at said exit end into a catch basin surrounding said exit end, said stream swirling outwardly as said stream flows into said catch basin having a liquid level proximate said exit end to permit said gas bubbles with said attached hydrophobic particles to float toward a peripheral edge of said catch basin; and   vii) means to separate gas bubbles with said attached hydrophobic particles from heavier particles by collecting outwardly said floating gas bubbles with attached hydrophobic particles with an upper zone of said catch basin, while heavier particles sink downwardly of said catch basin, and removing heavier particles from a lower zone of said catch basin to effect separation.   
     
     
         15 . An apparatus, for new flotation systems and retrofitting to existing flotation systems, for separation of hydrophobic particles from mixture of water and insoluble liquid or liquids through hydrophobic particles entrainment with gas bubbles in a mixture of water and insoluble liquid or liquids, said apparatus comprising:
 i) a vessel consisting of a cylindrical tube defining an interior cylindrica chamber with a cylindrical inner wall, and with enclosed ends,   ii) means for introducing a stream of a mixture of water and insoluble liquid or liquids tangentially of said inner wall, said stream introducing means being positioned in an input zone of said chamber to direct said stream in a manner, to develop a spiral flow of said stream along said inner wall toward the opposite end,   iii) at least one gas entry port, for introducing gas into said inner chamber through means located along at least a portion of said chamber inner wall and extending at least in part there around, for introducing gas orthogonally into said inner chamber as said stream passes over said gas introduction means;   iv) said chamber being of sufficient length to provide a residence time for said stream in said chamber to permit a diffusion of gas into said stream,   vi) means to discharge said stream with hydrophobic particles attached to gas bubbles at said exit end into a catch basin surrounding said exit end, said stream swirling outwardly as said stream flows into said catch basin having a liquid level proximate said exit end to permit said gas bubbles to float toward a peripheral edge of said catch basin; and   vii) means to separate gas bubbles with said attached hydrophobic particles from heavier particles by collecting outwardly said floating gas bubbles with attached hydrophobic particles with an upper zone of said catch basin, while heavier particles sink'downwardly of said catch basin, and removing heavier particles from a lower zone of said catch basin to effect separation.   
     
     
         16 . An apparatus according to  claim 10  or  11  or  12  or  13  or  14  or  15 , wherein said means located along at least a portion of said chamber inner wall and extending at least in part there around, for introducing gas consists a porous wall forming at least a portion of said chamber inner wall. 
     
     
         17 . An apparatus according to  claim 10  or  11  or  12  or  13  or  14  or  15  or  16 , wherein said gas introducing means consists of material having porosity with mean pore size of no greater than 100 microns. 
     
     
         18 . An apparatus according to  claim 10  or  11  or  12  or  13  or  14  or  15  or  16  or  17 , wherein said stream introducing means allow introduction of said stream in sufficient volume and pressure to develop a vortex in said stream extending along said inner wall. 
     
     
         19 . An apparatus according to  claim 18 , wherein said stream introducing means controls the velocity of said stream to generate centrifugal forces for said vortex to within a range of 20 to 100 Gs within said vessel. 
     
     
         20 . An apparatus according to  claim 12  or  13  or  14  or  15 , wherein said means to remove said separated heavier particles consists of an underflow line. 
     
     
         21 . An apparatus according to  claim 12  or  13  or  14  or  15 , wherein said means to remove said separated heavier particles consists of a gravity drain. 
     
     
         22 . An apparatus according to  claim 12  or  13  or  14  or  15  or  20  or  21 , wherein said means to discharge said stream with hydrophobic particles attached to gas bubbles at said exit end into a catch basin and said means to separate gas bubbles with said attached hydrophobic particles from heavier particles consists of i) a catch basin surrounding an open upper end of said chamber to receive said stream overflowing said open upper end, ii) said upper end having a smoothly curved edge portion to facilitate a smooth transition in flow of said stream from a vertical direction to an outward direction as said stream overflows into said catch basin, iii) means for collecting froth generated in said stream by bubbles introduced by said gas introducing means, said froth collecting means surrounding said catch basin, a weir being provided around said catch basin to define an overflow for froth floating outwardly of said catch basin, whereby froth overflowing said weir is collected in said froth collecting means, iv) said catch basin having an outlet in its lower portion to permit removal of said sinking heavier particles and remaining stream, v) said froth collecting means having an outlet to permit removal of froth from said collecting means, vi) said catch basin outlet having means for controlling flow of liquid to maintain in said catch basin an acceptable height of liquid to permit froth to overflow said weir. 
     
     
         23 . An apparatus according to  claim 22 , wherein said means to separate said gas bubbles with said attached hydrophobic particles from heavier particles include skimming means to mechanically gather said gas bubbles with said attached hydrophobic particles outwardly of said catch basin. 
     
     
         24 . An apparatus according to  claim 22  or  23 , wherein said smoothly curved edge portion is parabolic in cross-section. 
     
     
         25 . An apparatus according to  claim 22 , wherein said froth collecting means is an annular trough for receiving overflowing froth, said trough sloping towards said froth outlet to provide collection of froth. 
     
     
         26 . An apparatus according to  claim 25 , wherein said catch basin is sloped towards said catch basin outlet, with means for sensing liquid level in said catch basin, said sensing means having input to said flow controller to varying flow proportional to height in said catch basin to maintain thereby a desired height in said catch basin during flow of slurry along said chamber.