Classifying – separating – and assorting solids – Fluid suspension – Liquid
Patent
1995-12-18
1998-06-30
Lithgow, Thomas M.
Classifying, separating, and assorting solids
Fluid suspension
Liquid
252 61, B03D 102, B03D 106, B03D 1012
Patent
active
057720428
DESCRIPTION:
BRIEF SUMMARY
This invention relates to the processing of mineral ores. More specifically, it is directed to improvements in the froth flotation separation process, particularly with respect to the collectors used in such a process.
Froth flotation is an important and versatile mineral-processing technique whereby the mining of low-grade and complex ore bodies can be undertaken which otherwise would be regarded as uneconomic. Froth flotation of minerals have been practised for many years and is the main procedure for processing sulphide minerals. Whilst the theory of froth flotation is complex and not yet fully understood, it is well known that the process utilizes the differences in physico-chemical surface properties of the various minerals. After treatment with reagents, such differences in surface properties become apparent. For flotation to take place, an air-bubble must be able to attach itself to a particle, and lift it to the water surface. The process can only be applied to relatively fine particles, because if they are too large the adhesion between the particle and the bubble will not support particle weight and the bubble will therefore drop its load.
The air-bubbles can only stick to the mineral particles if they can displace water from the mineral surface, which can only occur if the mineral is, at least to some extent, hydrophobic. Having reached the surface, the air-bubbles can only continue to support the mineral particles if they can form a stable froth, otherwise they will burst and drop the mineral particles. To achieve these conditions, it is necessary to use various chemical reagents such as frothers, collectors and modifiers as are well known in the art.
As most minerals are not water repellent in their natural state, the most important of these flotation reagents are the collectors. These collectors adsorb onto the mineral surface, rendering it hydrophobic and facilitating bubble attachment. The collectors are organic compounds which render selected minerals water-repellent by adsorption of molecules or ions onto the mineral surface, reducing the stability of the hydrated layer separating the mineral surface from the air-bubble to such a level that attachment of the particle to the bubble can be made on contact.
Collector molecules may be ionizing compounds, which dissociate into ions in water, or non-ionizing compounds, which are practically insoluble, and render the mineral water-repellent by covering its surface with a thin film.
The most widely used collectors are of the sulphydryl type, which contain a polar bivalent sulphur group. These collectors are very powerful and selective in the flotation of sulphide minerals and the most widely used of these collectors are the xanthates, dithiophosphates and dithiocarbamates. Of these, the xanthates are most important for sulphide mineral flotation. See Crozier (Flotation, Theory, Reagents and Ore Testing, Pergamon Press, 1992) which is incorporated herein by reference.
Conventionally, collectors are added to the flotation pulp during or subsequent to grinding or during the flotation procedure itself.
Collectors such as xanthates adsorb from the liquid to the sulphide mineral surface. This forms the hydrophobic identity on the sulphide mineral surface. Once in the flotation cell, this sulphide mineral is then captured by the introduced air bubbles and subsequently recovered.
Xanthates and similar thiol compounds can also oxidize and the obtained dixanthogens and similar products of the oxidation are themselves collectors. Some limited attempts have been made to utilize these oxidation products as the principal collectors and prior art includes the deliberate electrochemical oxidation of xanthates to dixanthogens before their addition to flotation cells or conditioning tanks. However, since the dixanthogens have limited solubility in the flotation pulp they have not found commercial use.
The inventors have found that an improvement in flotation separation and recovery of desired sulphide minerals can be achieved where collector reagents are introduce
REFERENCES:
patent: 1350364 (1920-08-01), Dosenbach
patent: 1354031 (1920-09-01), Dosenbach
patent: 1365281 (1921-01-01), Scott
patent: 1418514 (1922-06-01), Bailey
patent: 1508478 (1924-09-01), Scott
patent: 3033363 (1962-05-01), Weston
patent: 3202281 (1965-08-01), Weston
patent: 3255999 (1966-06-01), Weston
patent: 4410439 (1983-10-01), Crozier
Davies Jonathan James
Manlapig Emmanuel
Nott Mark Cleeton
Lithgow Thomas M.
Ross P.C. Sheridan
Swartz Douglas
University of Queensland
LandOfFree
Method of mineral ore flotation by atomized thiol collector does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of mineral ore flotation by atomized thiol collector, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of mineral ore flotation by atomized thiol collector will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1850474