US1338264A - Edwin bryant thornhill - Google Patents

Description

E. B. THORNHILL.

FLOTATION PROCESS.

APPLICATION FILED MAR. 8. 1918.

1,338,264. Patented Apr. 27, 1920.

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UNITED STATES PATENT OFFICE.

EDWIN BRYANT THORNHILL, '01? OTTAVIA, ONTARIO, CANADA, ASSIGNOR TO THE GENERAL ENGINEERING COMPANY, INCORPORATED, 0F SALT LAKE CITY,

UTAH, A CORPORATION OF UTAH.

FLOTATION PROCESS.

Specification of Letters Patent.

Patented Apr. 27, 1920.

Application filed. March 8, 1918. Serial No. 221,266.

To aZZ whom it may concern:

Be it known that I, EDWIN BRYANT TironNrnLL, a citizen of the United States, resident of the city of Ottawa, in the Province of Ontario, Dominion of Canada, have invented certain new and useful Improvements in Flotation Processes, of which the following is a specification.

This invention relates to flotation processes, and the objects of the invention are to adapt such processes to the recovery of the mineral contents of ores (such as molybdenite) in which certain fine mineral particles, when freed from their gangue, tend to flocculate or segregate together in clusters in preference to other mineral particles. It is usual in flotation processes to produce what is termed a flotation concentrate, by passing through, or otherwise introducing finely divided air into a mixture of ground ore, water and oil. With some ores (such as those containing molybdenite) it is found difficult with this procedure alone to make a flotation concentrate of sufficiently high grade, particularly when treating ores of low mineral contents, or those containing other minerals.

I have discovered that certain minerals, when so treated in a water-oil mixture, will flocculate or coagulate together, while other minerals, or the gangue that may be pres out, will not; and this property may be taken advantage of to effect a separation of the desirable mineral from the gangue, or the other undesirable minerals present, by screening, all carried out in the manner hereinafter more fully set forth and described.

The process has been especially worked out in connection with molybdenum ores, and the present specifications have been written with special reference to such ores, but it is no doubt possible to extend its application to other ores having the same physical characteristics.

In practising this invention, the ore is first ground to the necessary degree of fineness, to liberate the minerals, and mixed with an oil or a mixture of different oils, and water in the manner usually practised with flotation processes. The oil used is preferably some petroleum product, such as coal oil, the quantity of which and other technical details being determined by experiment in the manner well known in the art.

The flotation process is then carried on in the usualway to produce ultimately, a flotation concentrate, containing a relatively large percentage of the desirable mineral contents of the ore (molybdenite) in a flocculated form.

To separate this mineral content from the other minerals present, or the gangue, in accordance with the present invention, the flotation concentrate is then subjected to a screening operation, by which the flocculated mineral (molybdenite) is retained on the meshes of the screen, and the unflocculated minerals (such as iron or copper pyrite) and the gangue pass through the meshes.

Any suitable type of screen for this purpose may be used and the-apertures may be varied so as to produce the result desired. On an ore crushed to 100 mesh,I have found that an 80 mesh screen is effective in separating the gcrater part' of the molybdenite, but a finer screen, or even a coarser one, might better suit the requirements in some cases; this being due to the fact that the small particles of the molybdenite flocculate or coagulate together and remain on the screen, while the particles of gangue, or the other unflocculatable minerals, pass through.

The material passing through the screen may be considered as a retreatment product, and be returned back into the original circuit, to be once again acted upon, or in some cases, may be disposed of in other ways.

The drawings illustrate diagrammatically an apparatus for carrying out the process. In the drawings, A represents the container for the flotation re-agents. B represents the roughing cell of the flotation apparatus, and 0 represents the cleaning cell of the flotation apparatus, to each of which cells air is forced under pressure from a blower D through suitable perforated air chambers 10 in the bottom of the cells. The froth formed on the surface of the roughing cell is transferred by the pump E to the cleaning cell. The froth concentrates from the cleaning cell are adapted to pass by gravity to a trough F, and from this trough to the top of the traveling belt screen G, from which the oversize pass into a bin H.

The undersizc from the screen and tailings from the cell 0 being returned by a pump I to the cell B, the tailings from the cell B usually goes to waste. It would be understood that both the flotation cells B and C are formed in the manner Well known in the art and which is practised in the ordinary flotation process.

As many changes could be made in the above process and many apparently widely different embodiments of my invention Within the scope of the claim could be employed without departing from the spirit or scope thereof, it is intended that all mat ter contained in the above specification and accompanying drawings, be interpreted as illustrative and not in a limiting sense.

What I claim as my invention is: The herein described process of coagulating certain minerals in preference to others by flotation, screening the resulting concentrates whereby the coagulated mineral is held on the screen, and the uncoagulated ones pass through, and returning the same back into the original feed for retreatment. In witness whereof I have hereunto set my hand in the presence of a witness.

EDWVIN BRYAN T THORNHILL. lVitness:

RUssEL B. SMART.

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