Separation of normally hydrophobic plastic materials by froth flotation

Claim 2

A process for separating by froth flotation a targeted particulate synthetic, organic plastic material having normally hydrophobic surface characteristics from a mixture of said targeted plastic material and at least one other different type of such particulate plastic material, said process comprising the steps of: (a) conditioning said mixture in an aqueous medium consisting essentially of a heteropolar surfactant having a hydrophile-lipophile balance (HLB) value greater than 5 and water to produce a conditioned pulp, the amount of said heteropolar surfactant being sufficient to depress said targeted plastic material by making the surfaces thereof hydrophilic without substantially affecting the hydrophobicity of the surfaces of said at least one other type plastic material; (b) introducing gas bubbles into the conditioned pulp while in a flotation cell, whereby the gas bubbles selectively adhere to the surfaces of said at least one, other different type plastic material and cause said at least one other different type plastic material to float; (c) recovering a cell product containing said targeted plastic material; and (d) recovering a float fraction containing said at least one ether different type plastic material.

Claim 3

A process according to claim 1 wherein the targeted plastic materials in said mixture have a contact angle of at least 30°, measured at a temperature of 20° C.

Claim 4

A process according to claim 2 wherein the targeted plastic materials in said mixture have a contact angle of at least 50°, measured at a temperature of 20° C.

Claim 5

A process according to claim 1 wherein the plastic materials in said mixture have a particle size less than about 0.5 inch.

Claim 6

A process according to claim 4 wherein the plastic materials in said mixture have a particle size less than about 0.25 inch.

Claim 7

A process according to claim 1 wherein said surfactant is cationic, anionic, nonionic or amphoteric.

Claim 8

A process according to claim 6 wherein the HLB value of said surfactant is at least 10.

Claim 9

A process according to claim 6 wherein said surfactant is an ethoxylated surfactant containing polyoxyethylene in its structure.

Claim 10

A process according to claim 6 wherein the amount of said surfactant is within the range of about 0.0005 to about 50 grams per liter of water in said aqueous medium.

Claim 11

A process according to claim 6 wherein the amount of said surfactant is within the range of about 0.01 to about 2 grams per liter of water in said aqueous medium.

Claim 12

A process according to claim 6 wherein the plastic materials in said mixture are selected from the group consisting of polyolefins, polyesters, polyamides, celluloses, polyurethanes, polyethers, poly sulfides, phenolic resins, fluorocarbon polyphers and mixtures thereof.

Claim 13

A process for separating by froth flotation first and second targeted particulate synthetic, organic plastic materials having normally hydrophobic surface characteristics from a mixture of said first and second targeted plastic materials and at least one other different type of such particulate plastic material, said process comprising the steps of: (a) conditioning said mixture of plastic materials in an aqueous medium consisting essentially of a heteropolar surfactant having a hydrophile-lipophile balance (HLB) value greater than 5 and water to produce a conditioned pulp, the amount of said heteropolar surfactant being sufficient to depress said first targeted plastic material by making the surfaces thereof hydrophilic without substantially affecting the hydrophobicity of the surfaces of said second targeted plastic material and said at least one other different type plastic material; (b) introducing gas bubbles into the conditioned pulp while in a flotation cell, whereby the gas bubbles selectively adhere to the surfaces of said second targeted plastic material and said at least one other different type plastic material and cause said second targeted and said at least one other different type plastic material to float; (c) recovering a first cell product containing said first targeted plastic material; (d) recovering a first float fraction containing said second targeted and said at least one other different type plastic materials; (e) conditioning said first float fraction with a sufficient amount of said surfactant to depress said second targeted plastic material by making the surfaces thereof hydrophilic without substantially affecting the hydrophobicity of the surfaces of said at least one other different type plastic material; (f) introducing gas bubbles in the conditioned first float fraction while in a flotation cell, whereby the gas bubbles selectively adhere to the surface of said at least one other different type plastic material and cause said at least one other different type plastic material to float; (g) recovering a second cell product containing said second targeted plastic material; and (h) recovering a second float fraction containing said at least one other different type plastic material.

Claim 14

A process for separating by froth flotation first and second targeted particulate synthetic, organic plastic materials having normally hydrophobic surface characteristics from a mixture of said first and second targeted plastic materials and at least one other different type of such particulate plastic material, said process comprising the steps of: (a) conditioning said mixture of plastic materials in an aqueous medium consisting essentially of a heteropolar surfactant having a hydrophile-lipophile balance (HLB) value greater than 5 and water to produce a conditioned pulp, the amount of said heteropolar surfactant being sufficient to depress said first targeted plastic material by making the surfaces thereof hydrophilic without substantially affecting the hydrophobicity of the surfaces of said second targeted plastic material and said at least one other different type plastic material; (b) introducing gas bubbles into the conditioned pulp while in a flotation cell, whereby the gas bubbles selectively adhere to the surfaces of said second targeted plastic material and said at least one other different type plastic material and cause said second targeted and said at least one other different type plastic material to float; (c) recovering a first cell product containing said first targeted plastic material; (d) recovering a first float fraction containing said second targeted and said at least one other different type plastic materials; (e) conditioning said first float fraction with a sufficient amount of said surfactant to depress said second targeted plastic material by making the surfaces thereof hydrophilic without substantially affecting the hydrophobicity of the surfaces of said at least one other different type plastic material; (f) introducing gas bubbles in the conditioned first float fraction while in a flotation cell, whereby the gas bubbles selectively adhere to the surface of said at least one other different type plastic material and cause said at least one other different type plastic material to float; (g) recovering a second cell product containing said second targeted plastic material; and (h) recovering a second float fraction containing said at least one other different type plastic material.

Claim 15

A process for separating by froth flotation a targeted particulate synthetic, organic plastic material having normally hydrophobic surface characteristics and a contact angle of at least 30°, measured at 20° C., from a mixture containing said targeted plastic material and at least two other different types of such particulate plastic material, said process comprising the steps of: (a) comminuting the plastic materials in said mixture to a particle size less than about 0.5 inch; (b) conditioning said mixture of plastic materials in an aqueous medium consisting essentially of a heteropolar, cationic, anionic, nonionic or amphoteric surfactant having a hydrophile-lipophile balance (HLB) value greater than 5 and water to produce a conditioned pulp, the amount of said surfactant being sufficient to depress said targeted plastic material by making the surfaces thereof hydrophilic without substantially affecting the hydrophobicity of the surfaces of said at least two other different type plastic materials; (c) introducing gas bubbles into the conditioned pulp while in a flotation cell, whereby the gas bubbles selectively adhere to the surfaces of said at least two other plastic materials and cause said at least two other different type plastic materials to float; (d) recovering a cell product containing said targeted plastic material; and (e) recovering a float fraction containing said at least two other different type plastic materials.

Claim 16

A process for separating by froth flotation a targeted particulate synthetic, organic plastic material having normally hydrophobic surface characteristics and a contact angle of at least 30°, measured at 20° C., from a mixture containing said targeted plastic material and at least two other different types of such particulate plastic material, said process comprising the steps of: (a) comminuting the plastic materials in said mixture to a particle size less than about 0.5 inch; (b) conditioning said mixture of plastic materials in an aqueous medium consisting essentially of a heteropolar, cationic, anionic, nonionic or amphoteric surfactant having a hydrophile-lipophile balance (HLB) value greater than 5 and water to produce a conditioned pulp, the amount of said surfactant being sufficient to depress said targeted plastic material by making the surfaces thereof hydrophilic without substantially affecting the hydrophobicity of the surfaces of said at least two other different type plastic materials; (c) introducing gas bubbles into the conditioned pulp while in a flotation cell, whereby the gas bubbles selectively adhere to the surfaces of said at least two other plastic materials and cause said at least two other different type plastic materials to float; (d) recovering a cell product containing said targeted plastic material; and (e) recovering a float fraction containing said at least two other different type plastic materials.

Claim 17

A process according to claim 13 wherein the HLB value of said surfactant is at least 10.

Claim 18

A process according to claim 14 wherein said surfactant is an ethoxylated surfactant containing polyoxyethylene in its structure.

Claim 19

A process according to claim 15 wherein the plastic materials in said mixture have a particle size less than about 0.25 inch.

Claim 20

A process according to claim 15 wherein the amount of said surfactant is within the range of about 0.0005 to about 50 grams per liter of water in said aquous medium.

Claim 21

A process according to claim 17 wherein the amount of said surfactant is within the range of about 0.01 to about 2 grams per liter of water in said aquous medium.

Claim 22

A process for separating by froth flotation first and second targeted particulate synthetic, organic plastic materials having normally hydrophobic surface characteristics and a contact angle of at least 30° measured at 20° C. from a mixture containing said first and second targeted plastic materials and at least one other different type of such particulate plastic material, said process comprising the steps of: (a) comminuting the plastic materials in said mixture to a particle size less than about 0.5 inch; (b) conditioning said mixture of plastic materials in an aqueous medium consisting essentially of a heteropolar, cationic, anionic, nonionic or amphoteric surfactant having a hydrophile-lipophile balance (HLB) value greater than 5 and water to produce a conditioned pulp, the amount of said surfactant being sufficient to depress said first targeted plastic material by making the surfaces thereof hydrophilic without substantially affecting the hydrophobicity of the surfaces of said second targeted material plastic material or said at least one other different type plastic material; (c) introducing gas bubbles into the conditioned pulp while in a flotation cell, whereby the gas bubbles selectively adhere to the surfaces of said second targeted plastic material and said at least one other different type plastic material and cause said second targeted and said at least one other different type plastic material to float; (d) recovering a first cell product containing said first targeted plastic material; and (e) recovering a first float fraction containing said second targeted and said at least one other different type plastic material; (f) conditioning said first float fraction with a sufficient amount of a said surfactant to depress said second targeted plastic material by making the surface thereof hydrophilic without substantially affecting the hydrophobicity of the surfaces of said at least one other different type plastic material; (g) introducing gas bubbles into the conditioned first float fraction while in a flotation cell, whereby the gas bubbles selectively adhere to the surfaces of said at least one other different type plastic material and cause said at least one other different type plastic material to float; (h) recovering a second cell product containing said second targeted plastic material in the cell product; and (i) recovering a second float fraction containing said at least one other different type plastic material.

Claim 23

A process for separating by froth flotation first and second targeted particulate synthetic, organic plastic materials having normally hydrophobic surface characteristics and a contact angle of at least 30° measured at 20° C. from a mixture containing said first and second targeted plastic materials and at least one other different type of such particulate plastic material, said process comprising the steps of: (a) comminuting the plastic materials in said mixture to a particle size less than about 0.5 inch; (b) conditioning said mixture of plastic materials in an aqueous medium consisting essentially of a heteropolar, cationic, anionic, nonionic or amphoteric surfactant having a hydrophile-lipophile balance (HLB) value greater than 5 and water to produce a conditioned pulp, the amount of said surfactant being sufficient to depress said first targeted plastic material by making the surfaces thereof hydrophilic without substantially affecting the hydrophobicity of the surfaces of said second targeted material plastic material or said at least one other different type plastic material; (c) introducing gas bubbles into the conditioned pulp while in a flotation cell, whereby the gas bubbles selectively adhere to the surfaces of said second targeted plastic material and said at least one other different type plastic material and cause said second targeted and said at least one other different type plastic material to float; (d) recovering a first cell product containing said first targeted plastic material; and (e) recovering a first float fraction containing said second targeted and said at least one other different type plastic material; (f) conditioning said first float fraction with a sufficient amount of a said surfactant to depress said second targeted plastic material by making the surface thereof hydrophilic without substantially affecting the hydrophobicity of the surfaces of said at least one other different type plastic material; (g) introducing gas bubbles into the conditioned first float fraction while in a flotation cell, whereby the gas bubbles selectively adhere to the surfaces of said at least one other different type plastic material and cause said at least one other different type plastic material to float; (h) recovering a second cell product containing said second targeted plastic material in the cell product; and (i) recovering a second float fraction containing said at least one other different type plastic material.

Claim 24

A process according to claim 19 wherein the HLB value of said surfactant is at least 10.

Claim 25

A process according to claim 20 wherein said surfactant is an ethoxylated surfactant containing polyoxyethylene in its structure.

Claim 26

A process according to claim 21 wherein the plastic materials in said mixture are selected from the group consisting of polyolefins, polyesters, polyamides, celluloses, polyurethanes, polyethers, polysulfides, phenolic resins, fluorocarbon polymers and mixtures thereof.

Claim 27

A process according to claim 22 wherein the plastic materials in said mixture have a particle size less than about 0.25 inch.

Claim 28

A process according to claim 22 wherein the amount of said surfactant is within the range of about 0.0005 to about 50 grams per liter of water in said aquous medium.

Claim 29

A process according to claim 24 wherein the amount of said surfactant is within the range of about 0.01 to about 2 grams per liter of water in said aquous medium.