Separation of limestone from limestone ore

A method for the separation of higher-grade limestone from lower-grade limestone and gangue present in particulate limestone ore which comprises:

• conditioning particulate limestone ore by contacting particulate limestone ore having a particle size of from about 1/4 inch to about 8 inches with at least one coupling agent selected from saturated and unsaturated carboxylic acids containing from about 4 to about 22 carbon atoms;
• combining with said coupling agent at least one fluorescent dye before or after conditioning the particulate limestone ore with the coupling agent, said coupling agent selectively coating calcium carbonate in the particulate limestone ore to the substantial exclusion of coating gangue;
• passing the conditioned particulate limestone ore in free-fall through an irradiation zone;
• exposing the conditioned particulate limestone ore to electromagnetic radiation as the conditioned particulate limestone ore free-falls through the irradiation zone to excite and induce fluorescence of the fluorescent dye to a degree sufficient to distinguish the coated higher-grade limestone particles from the lesser coated lower-grade limestone and the substantially non-coated gangue particles;
• passing the conditioned particulate limestone ore in free-fall through a fluorescence detection zone;
• detecting the intensity of fluorescence of particles falling through the fluorescence detection zone;
• separating fluorescing higher-grade limestone particles from lesser fluorescing lower-grade limestone and substantially nonfluorescing gangue particles by deflecting such fluorescing higher-grade limestone particles by impinging a directed fluid stream upon fluorescing higher-grade limestone particles;
• collecting deflected higher-grade limestone particles;
• and separately collecting free-falling, lower-grade limestone particles and gangue particles.

A method for the separation of higher-grade limestone from lower-grade limestone and the silicate-containing gangue present in particulate limestone ore, comprising:

• conditioning particulate limestone ore by contacting the particulate limestone ore with at least one coupling agent selected from the group consisting of aliphatic amines containing from about 8 to about 22 carbon atoms and beta amines containing from about 7 to about 21 carbon atoms;
• combining with said coupling agent at least one fluorescent dye before or after conditioning the particulate limestone ore with the coupling agent, said coupling agent selectively coating silicates in the particles to the substantial exclusion of coating calcium carbonate in the particles, providing a coating on gangue particles, relative lesser coating on lower-grade limestone particles and relative least coating on higher-grade limestone particles, passing the conditioned particulate limestone ore in free-fall through an irradiation zone;
• exposing the conditioned particulate limestone ore to electromagnetic radiation as the particulate limestone ore free-falls through the irradiation zone to excite and induce fluorescence of the fluorescent dye to a degree sufficient to distinguish the coated gangue particles and lesser coated lower-grade limestone from least coated higher-grade limestone particles;
• passing the conditioned particulate limestone ore in free-fall through a fluorescence detection zone;
• detecting the intensity of fluorescence of the particle falling in free-fall through the fluorescence detection zone;
• separating fluorescing, coated gangue and lower-grade limestone particles from higher-grade limestone particles by deflecting fluorescing, coated gangue particles and lower-grade limestone particles from such free-fall path by impinging a directed fluid stream upon each gangue and lower-grade limestone particle;
• collecting free-falling, higher-grade limestone particles;
• and separately collecting deflected gangue and lower-grade limestone particles.

A method for the separation of higher-grade limestone from lower-grade limestone and the gangue present in particulate limestone ore which comprises:

• (a) conditioning the particulate limestone ore of a particle size of from about 1/4 inch to about 8 inches with a coupling agent consisting essentially of a coupling agent selected from saturated and unsaturated carboxylic acids containing from about 4 to about 22 carbon atoms, selectively coating the calcium carbonate in the limestone with the coupling agent to the substantial exclusion of coating gangue in combination with providing at least one fluorescent dye to said coupling agent;
• (b) water rinsing excess coupling agent and fluorescent dye from the particulate limestone ore;
• (c) irradiating in an irradiating zone the fluorescent dye contained on the conditioned particulate limestone ore to excite and induce fluorescence of the fluorescent dye to a degree sufficient to distinguish the coated higher-grade limestone particles from the coated lower-grade limestone and the substantially non-coated gangue particles and separating the fluorescing coated higher-grade limestone particles from the coated lower-grade limestone and nonfluorescing gangue particles;
• (d) passing the conditioned particulate limestone ore in free-fall through a fluorescence detection zone and detecting the intensity of fluorescence of falling particles through the zone;
• and
• (e) separating the fluorescing higher-grade limestone particles from the lesser fluorescing lower-grade limestone and substantially nonfluorescing gangue particles by deflecting fluorescing higher-grade limestone particles by impinging a directed fluid stream upon such fluorescing higher-grade limestone particle;
• collecting the deflected higher-grade limestone particles;
• and separately collecting free-fall, lower grade limestone particles and gangue particles.

A method for the separation of higher-grade limestone from lower-grade limestone and/or the silicate-containing gangue present in particulate limestone ore, comprising:

• (a) conditioning the particulate limestone ore with at least one coupling agent selected from the group consisting of aliphatic amines containing from about 8 to about 22 carbon atoms and beta amines containing from about 7 to about 21 carbon atoms, said coupling agent selectively coating silicates in the gangue particles to the substantial exclusion of coating the calcium carbonate particles, in combination with providing at least one fluorescent dye to said coupling agent;
• (b) radiating the fluorescent dye of the conditioned particulate limestone ore to excite and induce fluorescence of the fluorescent dye to a degree sufficient to distinguish the coated gangue particles and partially coated lower-grade limestone particles from the lesser coated higher-grade limestone particles and separating the fluorescing, coated gangue and lower-grade limestone particles from the higher-grade limestone particles;
• (c) passing the conditioned particulate limestone ore in free-fall through a fluorescence detection zone and detecting the intensity of fluorescence of particles in free-fall through the fluorescence detection zone;
• (d) separating the fluorescing, coated gangue and lower-grade limestone particles from the higher-grade limestone particles by deflecting fluorescing, coated gangue particle and lower-grade limestone particles from such free-fall path by impinging a directed fluid stream upon gangue and lower-grade limestone particles;
• and
• (e) collecting free-falling, higher-grade limestone particles and separately collecting the deflected gangue and lower-grade limestone particles.