US1290166A - Flotation process. - Google Patents

Description

BUDOLF GAHL, or mam;

ARIZONA, ASSIGNOR TO THE U-T AH COPPEB GOMPANY, A.

CORPORATION OF NEW JERSEY,

. FLOTATION. rnoonss.

1,290,166. t No Diawingl To all whom it may concern: Be it known that I, Rooonr GAHL, a

citizen of the United States, residing at Miami, in the county of Gila and State of Arizona, have invented certain new and useful Improvements in Flotation Processes, of

' which the following is a specification y This invention relates to so-called flotation processes for the concentration of ores,

and comprises a novel procedure by means of which the efiiciency of these flotation processes may-be very greatly improved, par

ticularly in their application to certain oreswhich are unsuited for treatment by the ordinary methods. The invention will be described-in'its application to the flotation of sulfid' or even carbonate ores containing small percentages of copper, by means of air. bubbles used 1n conjunction .with suitable hydrocarbon substances, such as coal-tar and It is believed, however, that allied products. the present improvement is'applicable to flotation processes in general, and the invention is not therefore limited to the specific conditions recited by Way of example.

It. is a matter of common observation that vcertain ores or ore-batches do not respond well to the flotation treatment; and more or less refractory ores have been discovered wherever concentration by flotation has been attempted. Even in ore bod1es consisting largely of good flotation ores, portions are found which are less suited for this treatment; and in ore mixtures which'res'pond well to flotation, portions can frequently be sorted out which do not" so respond when treated by themselves; For this reason, the

mixing. of different ores has proven beneficial 1n a greatmany cases. In many cases, however, the ores necessary to constitute a properly responsive mixture are not available, and for such cases the process herein described Will prove particularly useful.

I have observed that ores which are refractory to the ordinary flotation treatment can be handled without difiiculty, and with a reasonably high degree of efficiency, provided there are added to the, ore, and thoroughly mixed therewith, certain solid sub stances which are not themselves floated, and which do not apparently enter at all into the flotation reaction. Among such additions I Specification of Letters Patent.

Patented Jan. 2, 1919. p

ticularly effective when introduced in the form of filings or other suitable state of fine subdivision. The iron may either be added in proper proportions to the feed entering the flotation machines, or it may be introduoed at a; previous point in the treatment, for example in the-grinding apparatus.

For example, if an .ore of the above-mentioned, imperfectly responsive type containing a small percentage of copper in the form of sulfid, is mixed with one-half to two per cent, or evenless by weight of iron filings, together with the usual proportion of oil or equivalent material, and the Whole is subjected to flotation in water or the usual flotation media, under otherwise standard con ditions, air in the form of bubbles being injected or stirred into the mass, it will be found that the ore responds well to the treatment, and that excellent flotation eiiiciencies are obtained. The following tabular statement of actual test runs upon a small scale 7 5 .Will serv to illustrate the results which are obtalnable Per Grams Per Test Grams Grams Grams Recovcent. concencent.

copper. copper trate. copper. mpper' 86 F46 4s 25. 60 12. 29 81. 57 F47 Y 27 s. so 2. as 15. 8%

F53 29 6. 16 p 1. 79 11.9% F54., 30 7.96 2.39 15.97 r55 59 21. 0s 12. 44 82. 7 F56 56 25. 80 14. 45 95. 0%

L27 37 28. 42 10. 51 81. 7% L28 34 28. 96 9. 85 78. 3% L29 76 5. 66 4. 30 '33. 4% L30 83 5. 06 4. 20 32. 9%

Referring to the above table,- tests marked F21, F22, F45, F46, F55, F56, were carried out with the addition to the 750 grams of ore of 10 grams of iron filings. In tests F27 and F28, two grams of iron filings were added. Tests F49 and F50 received ten grams of miscellaneous iron filings from the machine shop, and tests F51 and F52 received the same addition, the latter tests being made however by a difierent observer. F48, F53, and F 54; were blanks, only the regular oils and flotation media were used, no iron being added.

Test F 64 was made ;with the samerefractory ore, but instead of grinding it in a mill filled with flint pebbles, it was ground in a mill filled with steel balls, whereby particles.

of iron were introduced.

Tests L27 and L28 are blank tests on a good flotation ore, only the ordinary flotation made under identical Tests L29 and L30 were conditions, except 'for the addition of 10 grams Zinc filings.

It will be observed that with these particular ores, the eliiciency of the process was entirely dependent uponthe addition of iron.

The reasons underlying this observed effect are not as yet certainly known.

It is probable that the surface condition of oils being added.

. the iron exercises an important i fluence.

This is indicated by the fact which I have observed, that the addition of minute quantities of platinic chlorid to the solution materially increases the quantity of foam formed when air'is blown through a porous diaphragm into a suspension or solution of a frothing agent in water, to which finely-difinely-divided iron vided iron has been added. In this case'it is assumed that a small percentage of the iron is-su'perficially replaced by platinum.

Instead of mixing iro'n filings with the ore favorable results are obtained by introducing during the grinding or reduction process. For examplatest F64: in

the foregoing tabular statement illustrates. .theefiect of using steel mill instead 'ofthe flint pebbles usually employed for the final reduction of the ore. In

balls in the grinding this case iron in minute subdivision .is thoroughly incorporated with the ore, owing to the abrasive e'fi'ect balls; and although goes oxidation during and after the grinding by the action of the air and water, it is found that a certain portionof it persists as metal, and tests have shown that the observed faof the latter upon the vorable action upon the flotation is dueto this residual metal and not to the iron oxid or hydroxid which accompanies it. WVhen desired, the proportion of iron thus introduced maybe increased by the use of balls of softer iron or steel, by the addition to .the ore of some more highly abrasive material, bythe introduction of iron from other sources, or by a combination of such methods.

.Not all forms of finely-divided iron are equally effective: for example, when sponge iron was substituted for the iron filings, equally favorable results were not secured.

Furthermore, certain solid materials have been shown to exert a distinctly unfavorable effect upon theflotation process. For example,

Tests F47,

in whichthis iron largely underreferring to the foregoing tabular- 1,2e0,1ce I statement (tests L27 to L30, inclusive), it will be noted that the addition of a small proportion of zinc filings very markedly decreased the flotation efiiciency in the case of a normally good flotation ore.

It is obviously impossible to name all of the substanceswvhich may ultimately prove available for increasin the flotation efliciency, although the avai ability ofa'ny given substance is readily determined by simple ex periment in. the light of the information herein lven. her is it possible at the presout time to define such available substances by a classification based upon other chemical or physical properties Whichthey may pcstageously used for accomplishing a separation of'the kind described. Combinations of machines of various types may.be.employed. For instance, wherefconcentrating tables-are used for re-treating flotation tailings, metallic iron will largely go into the table concentrates, and may by means of magnets and conveyer belts, be transferred again to the flotation machine. 4 i

Although so far as is now known, the substances to be used as additions to theore in accordance with this invention are active only in solid form, it is to'be understood that they may be introduced in solution, chemical reactions 'bein'g' relied upon to precipitate them in the active solid form, as in the example of platinic chlorid above referred to. The present process is quite independentof special apparatus, and may be carried.

out in any of the standard forms of flotation machines now on the market. The ore'is either ground with the flotation agent, or is subsequently agitated therewitl The air bubbles may be introduced'as desired by any of the known methods, such as application of. a vacuum, injection through a porous bottom, or by drawing or blowing air into the pulp and distributing it therethrough in the form of small bubbles by violent'agita-,

tion.

1. A process of concentrating ores by bubble-flotation, which consists in mixing the ore with an extraneous solid capable of increasing the efliciency oi the flotation, concentrating the mixture by flotation, recovering the said extraneous solid from the floore, concentrating the mixture by flotation, tation tailings, and applying the recovered recovering the metallic iron from the flotasolid in the flotation of other bodies of ore. tion tailings, and applying the recovered 2. A process of concentrating ores by iron in the flotation of further bodies of ore. 1O 5 bubble-flotation which consists in mixing In testimony whereof I affix my signature. iron in suitably subdivided form with the RUDOLF GAHL.