Froth flotation
The chain is shortest in sodium ethyl xanthate that makes it highly selective to copper, nickel, lead, gold, and zinc ores.
[7] The rougher concentrate is normally subjected to further stages of flotation to reject more of the undesirable minerals that also reported to the froth, in a process known as cleaning.
Classified by the method of air absorption manner, it is fair to state that two distinct groups of flotation equipment have arisen:pneumatic and mechanical machines.
The Jameson cell uses neither impellers nor spargers, instead combining the slurry with air in a downcomer where high shear creates the turbulent conditions required for bubble particle contacting.
These additives include pine oil and various alcohols: methyl isobutyl carbinol (MIBC), polyglycols, xylenol (cresylic acid).
Froth flotation is "poised for increased activity due to their potential usefulness in environmental site cleanup operations" including recycling of plastics and metals, not to mention water treatment.
[15] Initially, naturally occurring chemicals such as fatty acids and oils were used as flotation reagents in large quantities to increase the hydrophobicity of the valuable minerals.
Since then, the process has been adapted and applied to a wide variety of materials to be separated, and additional collector agents, including surfactants and synthetic compounds have been adopted for various applications.
Later writers have pointed to Haynes's as the first "bulk oil flotation" patent, though there is no evidence of its being field tested, or used commercially.
[23] The generally recognized first successful commercial flotation process for mineral sulphides was invented by Frank Elmore who worked on the development with his brother, Stanley.
The Glasdir copper mine at Llanelltyd, near Dolgellau in North Wales was bought in 1896 by the Elmore brothers in conjunction with their father, William.
In 1897, the Elmore brothers installed the world's first industrial-size commercial flotation process for mineral beneficiation at the Glasdir mine.
The process was not froth flotation but used oil to agglomerate (make balls of) pulverised sulphides and buoy them to the surface, and was patented in 1898 (revised 1901).
In 1900, Charles Butters of Berkeley, California, acquired American rights to the Elmore process after seeing a demonstration at Llanelltyd, Wales.
[25] Because of Butters' reputation and the news of his failure, as well as the unsuccessful attempt at the LeRoi gold mine at Rossland, B. C., the Elmore process was all but ignored in North America.
Another flotation process was independently invented in 1901 in Australia by Charles Vincent Potter and by Guillaume Daniel Delprat around the same time.
During the first decade of the twentieth century, Broken Hill became the center of innovation leading to the perfection of the froth flotation process by many technologists there borrowing from each other and building on these first successes.
[30] Useful work was done by Leslie Bradford at Port Pirie and by William Piper, Sir Herbert Gepp and Auguste de Bavay.
[31] Henry Livingston Sulman was later recognized by his peers in his election as President of the (British) Institution of Mining and Metallurgy, which also awarded him its gold medal.
Butters's failures, as well as others, was followed after 1904, with Scotsman Stanley MacQuisten's process (a surface tension based method), which was developed with a modicum of success in Nevada and Idaho, but this would not work when slimes were present, a major fault.
[32] Minerals Separation, Ltd., which had set up an office in San Francisco, sued Hyde for infringement as well as the Butte & Superior company, both cases were eventually won by the firm in the U. S. Supreme Court.
Daniel Cowan Jackling and partners, who controlled Butte & Superior, also refuted the Minerals Separation patent and funded the ensuing legal battles that lasted over a decade.
[citation needed] In 1913, the Minerals Separation paid for a test plant for the Inspiration Copper Company at Miami, Arizona.
[33] John M. Callow, of General Engineering of Salt Lake City, had followed flotation from technical papers and the introduction in both the Butte and Superior Mill, and at Inspiration Copper in Arizona and determined that mechanical agitation was a drawback to the existing technology.
[35] The American Institute of Mining Engineers presented Callow the James Douglas Gold Medal in 1926 for his contributions to the field of flotation.
By that time, flotation technology was changing, especially with the discovery of the use of xanthates and other reagents, which made the Callow cell and his process obsolete.
Recent writers, because of the interest in celebrating women in science, champion Carrie Everson of Denver as mother of the process based on her 1885 patent.
But, as historian Martin Lynch writes, "Mineral Separation would eventually prevail after taking the case to the US Supreme Court [and the House of Lords], and in so doing earned for itself the cordial detestation of many in the mining world.
[40] The attachment of the bubbles to the particles is determined by the interfacial energies of between the solid, liquid, and vapor phases, as modeled by the Young/Dupre Equation.
Some systems combine the functionalities of these components by placing them at key locations where they can take part in multiple froth flotation mechanisms.
