Abstract: Methods of increasing the rate of separating hydrophobic and hydrophilic particles by flotation have been developed. They are based on using appropriate reagents to enhance the hydrophobicity of the particles to be floated, so that they can be more readily collected by the air bubbles used in flotation. The hydrophobicity-enhancing reagents include low HLB surfactants, naturally occurring lipids, modified lipids, and hydrophobic polymers. These methods can greatly increase the rate of flotation for the particles that are usually difficult to float, such as ultrafine particles, coarse particles, middlings, and the particles that do not readily float in the water containing large amounts of ions derived from the particles. In addition, new collectos for the flotation of phosphate minerals are disclosed.

Abstract: The present invention relates to a method for separating diamond from gangue minerals. In particular, this method relates to the addition of a first reagent or reagents which contact the diamond in diamond ore slurry to at least partially remove hydrophilic coatings from the diamond surfaces. A second reagent or reagents may also be added to the slurry so that the reagent may adsorb on the diamond surfaces and thereby enhance the hydrophobicity of diamonds. The increase in hydrophobicity may improve the flotation of diamonds.

Abstract: The present invention relates to a method for separating diamond from gangue minerals. In particular, this method relates to the addition of a first reagent or reagents which contact the diamond in diamond ore slurry to at least partially remove hydrophilic coatings from the diamond surfaces. A second reagent or reagents may also be added to the slurry so that the reagent may adsorb on the diamond surfaces and thereby enhance the hydrophobicity of diamonds. The increase in hydrophobicity may improve the flotation of diamonds.

Abstract: A new method of improving the process of dewatering fine particulate materials is disclosed. In this method, an aqueous slurry of fine particles is treated with appropriate hydrophobizing reagents so that the particulate material becomes moderately hydrophobic with its water contact angle considerably below 90°. A low hydrophile-lipophile balance (HLB) number surfactant is then added to the slurry, so that the surfactant molecules adsorb on the moderately hydrophobic surface primarily by hydrophobic attraction and, thereby, increase its contact angle close to or above 90°. By virtue of the greatly enhanced hydrophobicity, the water molecules adhering to the surface are destabilized and removed more readily by a mechanical dewatering process. Any nonionic surfactant with its HLB number below about 15 may be used for the hydrophobicity enhancement. The surfactants may be used in conjunction with appropriate solvents such as light hydrocarbon oils and short-chain alcohols.

Abstract: Methods of increasing the rate of separating hydrophobic and hydrophilic particles by flotation have been developed. They are based on using appropriate reagents to enhance the hydrophobicity of the particles to be floated, so that they can be more readily collected by the air bubbles used in flotation. The hydrophobicity-enhancing reagents include low HLB surfactants, naturally occurring lipids, modified lipids, and hydrophobic polymers. These methods can greatly increase the rate of flotation for the particles that are usually difficult to float, such as ultrafine particles, coarse particles, middlings, and the particles that do not readily float in the water containing large amounts of ions derived from the particles. In addition, new collectors for the flotation of phosphate minerals are disclosed.