Classifying – separating – and assorting solids – Fluid suspension – Liquid
Reexamination Certificate
2001-02-09
2004-12-07
Lithgow, Thomas M. (Department: 1724)
Classifying, separating, and assorting solids
Fluid suspension
Liquid
C252S061000
Reexamination Certificate
active
06827220
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to the beneficiating or concentrating of ores. In particular, this invention relates to collectors useful in ore beneficiating.
Flotation is a process for concentrating minerals from their ores. Flotation processes are well known in the art and are probably the most widely used method for recovering and concentrating minerals from ores. In a flotation process, the ore is typically crushed and wet ground to obtain a pulp. Additives such as flotation or collecting agents and frothing agents are added to the pulp to assist in subsequent flotation steps in separating valuable minerals from the undesired, or gangue, portion of the ore. The flotation or collecting agents can comprise liquids such as oil, other organic compounds, or aqueous solutions. Flotation is accomplished by aerating the pulp to produce froth at the surface. Minerals, which adhere to the bubbles or froth, are skimmed or other removed and the mineral-bearing froth is collected and further processed to obtain the desired minerals.
The basic techniques behind froth flotation is to use chemicals to increase the hydrophobicity of the mineral to be beneficiated to form a concentrate. Meanwhile, chemicals are added, as necessary, to decrease the hydrophobicity of unwanted (gangue) minerals, so that these minerals report to the slurry and are discarded as tail. The main alternative technique in froth flotation is “reverse flotation”. This consists of floating the gangue minerals as a concentrate and keeping the mineral of interest on the slurry.
Chemicals that promote hydrophobicity of a mineral are called out that mineral's “promoter” or “collector.” Collectors based on fatty acids have long been used in collecting one or more of the oxide minerals such as fluorspar, iron ore, chromite, scheelite, CaCO
2
, MgCO
2
, apatite, or ilmenite.
Also, early work used alkali metal salts of fatty acids, or soaps derived from natural oils by the process known as saponification. When an oil containing triglycerides is treated with a caustic solution under certain harsh processing conditions, the triglycerides disassociate into the alkali metal salts of the component fatty acids. The dissociation of the triglycerides into neutralized fatty acids is the saponification process. These neutralized fatty acids are soaps that act as non-selective flotation collectors.
Compounds containing sulfur, such as xanthanes, thionocarbamates, dithiophosphates, and mercaptans, will selectively collect one or more sulfide minerals such as chalcocite, chalcopyrite, galena, or sphalerite. Unfortunately, sulfur based collectors are often toxic, have repugnant odors or both. Amine compounds are used to float KCl from NaCl and for silica flotation. Petroleum-based oily compounds such as diesel fuels, decant oils, and light cycle oils, are often used to float molybdenite. Those oils are also used as an “extruderoil” that reduces the dosage of other more expensive collectors in the amine flotation of KCl.
Previous work on sulfide minerals has indicated that molecules containing sulfur are useful compounds for the froth flotation of sulfide minerals. These collectors are usually grouped into two categories: water-soluble and oil (i.e., hydrophobic) collectors. Water-soluble collectors such as xanthates, sodium salts of dithiophosphates, and mercapto benzothiazole have good solubility in water (at least 50 gram per liter) and very little solubility in alkanes. Oily collectors, such as zinc salts of dithiophosphates, thionocarbamates, mercaptans, and ethyl octylsulfide, have negligible solubility in water and generally good solubility in alkane.
Currently used collectors for most sulfide minerals are sulfur-based chemicals such as xanthanes, thionocarbamates, dithiophosphates, or mercaptans. These chemicals have problems with toxicity and or repugnant odors. In addition, these collectors can be very expensive. Therefore, a need exists for new collectors that are effective but not toxic or odiferous.
BRIEF SUMMARY OF THE INVENTION
This invention is directed to a method of beneficiating a mineral sulfide-containing material or a metallic species of gold, silver, copper, palladium, platinum, iridium, osmium, rhodium, or ruthenium by froth flotation in the presence of a collector as well as a collector for beneficiation of sulfide minerals, precipitates, or metallic species. In both aspects, the collector includes at least one oil which is either an essential oil or a natural or synthesized oil comprising triglycerides containing fatty acids of only 20 carbons or less, or an ester made from a fatty acid and an alcohol.
In the method aspect of the invention, the method includes the steps of (1) providing an aqueous slurry of the mineral sulfide-containing or metal-containing material, (2) adding a selective collector to the slurry, the collector comprising at least one oil selected from the group consisting of (a) a natural oil or synthesized oil comprising triglycerides containing fatty acids of only 20 carbons or less, or an ester made of fatty acid and an alcohol; and (b) an essential oil; (3) selectively floating the mineral sulfide; and, then (4) recovering the mineral.
In the collector aspect of the invention, a collector is provided for beneficiation of sulfide minerals or precipitates from ores, concentrates, residues, tailings, slags, or wastes. The collector includes at least one sulfur-containing sulfide mineral flotation promoter; and at least one oil selected from the group consisting of (1) a natural or synthesized oil comprising at least one triglyceride, or at least one ester made from a fatty acid and an alcohol; and (2) an essential oil.
This invention has an advantage that the specified triglyceride, specially, or essential oil will selectively float sulfide minerals by itself or mixed with other collectors. This and other advantages will be apparent from the detailed description of the invention that follows.
DETAILED DISCLOSURE OF THE INVENTION
The subject invention provides materials and methods useful in the recovery of minerals. These materials and methods are specifically applicable to froth flotation procedures; whereby, minerals are removed and recovered from complex mixtures of ores, residues, concentrates, slags, and wastes. The subject invention can be used in remediation processes to remove unwanted materials or may be used in mining processes to recover valuable minerals. Specifically exemplified herein is the use of certain triglycerides, esters of the fatty acids and long chain alcohols, and essential oils of both terpene and aromatic chemistries. Any of these oils may be used alone, in mixtures, or in combination with other collectors.
In the method aspect of the invention, the method includes the steps of (1) providing an aqueous slurry of the mineral sulfide-containing or metal-containing material, (2) adding a selective collector to the slurry, the collector comprising at least one oil selected from the group consisting of (a) a natural oil or synthesized oil comprising triglycerides containing fatty acids of only 20 carbons or less, or an ester made from a fatty acid and an alcohol; and (b) an essential oil; (3) selectively floating the mineral sulfide; and, then (4) recovering the mineral.
In the collector aspect of the invention, a collector is provided for beneficiation of sulfide materials or precipitates from ores, concentrates, residues, tailings, slags, or wastes. The collector includes at least one sulfur-containing sulfide mineral flotation promoter; and at least one oil selected from the group consisting of (1) a natural or synthesized oil comprising at least one triglyceride, or at least one ester made from a fatty acid and an alcohol; and (2) an essential oil.
Preferably the mineral sulfide-containing material selected from the group consisting of chaiconine, chalcopyrine, bornite, galena, sphalerite, pentlandite, molybdenite, and other sulfide minerals containing silver, gold, platinum, palladium, iridium, rhodium, and osmium, either in the crystal structure
Bauer Kathy
Greene Michael G.
Reber Bonnie J.
Reber Norman R.
Young Sharon K.
Brinks Hofer Gilson & Lione
Lithgow Thomas M.
Reber Bonnie J.
Versitech, Inc.
Zayia Gregory H.
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