US2297689A - Separation of feldspar from quartz - Google Patents

Description

Patented Oct. 6, 1942 SEPARATION OF FELDSPAR FROM QUARTZ Robert Gibson OMeara, Tuscaloosa, Ala., assignor to the Government of the United States of America, as represented by the Secretary of the Interior No Drawing. Application April 5, 1940,

Serial No. 328,083

10 Claims. (Cl. 209-466) (Granted under the act of March 3, 1883 as amended April 30, 1928; 370 O. G. 757) The invention described herein, if patented, may be practiced and used by or for the United States Government for governmental purposes without the payment of any royalty thereon.

This invention relates to the preparation of ores for separation by froth flotation and/or agglomerate table concentration film flotation or similar methods of concentration and particularly to the beneflciation of feldspar ores and their products. The invention is especially applicable to the froth flotation and/or table concentration of feldspar from quartz and the separation of feldspar from other associated minerals. It is a continuation in part of application Serial Number 117,470.

In application of the present invention, great flexibility is achievable, as is particularly desirous in view of the wide variation in ores encountered. Thus by this invention the various feldspars can be floated and/or tabled from the quartz in mixtures of various proportions. In addition, the feldspar can be separated from some of the other commonly associated gangue minerals such as mice. and garnet by modifying the procedure.

The'separation according to this invention is not based upon the same properties as any of the methods of beneflciation commonly used in the feldspar industry. In continuance of experimentation on the flotation of quartz from feldspar set-forth in a previous patent application, Ser. No. 117,470, it was discovered that changing from hydrochloric acid to hydrofluoric acid as a modifying agent reversed the order of flotation.

In this case the feldspar was floated from the quartz. A feed too coarse for flotation, but prepared in the same manner as for flotation also was separated on a concentrating table. The feldspar agglomerated or filmed over the side of the table and the quartz was carried out by the rifiles to the end of the table. In this case the separation was not'based on the specific gravity of the quartz and feldspar but upon the surface preparation. The feldspar was rendered waterrepellant as in flotation, and filmed whereas the quartz remained wetted by water.

In practicing the preparation of the ore according to this invention, it is desirable that the product be reasonably fine grained and that the mineralogical constituents be liberated. The ground ore is mixed with water forming a pulp or slurry tov which is added the necessary reagents. The pulp is conditioned to insure mixing, and the separation is effected on any of the well known types of flotation machines and/r concentrating tables.

The preparation of the feed for separation of the feldspar from the quartz by froth flotation or table concentration is effected in this invention by the use of cationic reagents of the type of trimethyl cetyl-ammonium bromide or lauryl amine hydrochloride in conjunction with hydrofluoric acid, fluosilicic acid, other complex fluorine acids, their salts or their derivatives. In addition, a small'amount of hydrocarbon oils is beneficial in the treatment of the coarser mate rial. Some of the gangue minerals other than quartz are eliminated in this treatment and others can be eliminated by first depressing the quartz and feldspar with a mineral acid and later floating the feldspar in the normal manner by the addition of fluorides and/or fluosilicates, fluoborates, or other fluorine complexes of polyvalent elements like vanadium; zirconium or titanium.

Whereas the original discovery of the unexpected reversal in selectivity in filming minerals took place with chemically pure hydrofluoric acid, it soon was found that impure hydrofluoric acid gave superior results and in attempting to find the cause, fluosilicic acid was tried as the most probable impurity. Other fluorine-metal complexes were then tested and specially good results were obtained with fluoborates and fluotitanates or the complexes formed by dissolving oxides of these polyvalent metals in excess hydrofluoric acid. Whereas chemically pure hydrofluoric acid might give a grade of feldspar concentrate, the addition of these further modifiers would raise the grade of the concentrate to over 98%. The hydrofluoric acids of commerce are much better adapted to the desired separation than are the pure hydyrofluoric acid preparations available.

For the purpose of illustrating this invention, two examples are here given. comprising applications which have been made of these inventions to feldspar bearing products (1) in which the feldspars were prepared and separated from the quartz by froth flotation and (2) in which the feldspars were prepared and separated from the quartz by table concentration.

The feldspar ore consisted of plagioclase fe df spar. albite and oligoclase. potash feldspar, microcline and orthoclase. quartz and minor amounts of mica. The ore was ground through 20 mesh for liberation of the constituents and sized on 48 mesh. The plus 48 mesh size was prepared and separated on a concentrating table. and the minus 48-mesh material was prepared and separated by flotation.

The reagents used in treating the feed were as follows:

Pounds per ton of feed Reagents (2) on (1) On plus 48- minus 48- mesh part mesh part of feed of feed Lauryl amine hydrochloride "m... 0. 24 0. 24 Hydrofiuoric acid 2. 3 2. 3 Fuel oil 5.4

These amounts of reagents gave satisfactory results but they could undoubtedly be reduced and rebalanced without sacrificing results. The or der of addition of the reagents appeared to have little effect on the subsequent separation. The results of the tests follow:

(1) Flotation test on minus 48-mesh part of feed Distri- Assay Products Weight button A110 of Autos Percent Percent Rougher concentrate 58. 5 19.63 97, 9 Rougher tailing 41. 5 .59 2. 1

Composite (minus 48-rnesh part of feed) 100.0 11.73 100.0

(2) Table concentration test on plus 48-1ncsh pant of feed Distri- Assay Products Weight bution of A120;

Percent Percent Table concentrate 44. 9 19. 18 94. 6 Table tailing 55. 1 89 5. 4

Composite (plus 8-1ncsh part of feed) l 100.0 9. 10 W0. 0

The resul s-of the combined flotation (1) and table concentration (2) test were:

ht A Eistri.

Combined )roducts "cig u 10H I of A110;

Percmi Percen! Table and flotation concentrate 49. 7 19. 37 96. 0

Table and flotation tailing 50. 3 .80 0

Composite (feed) 100.0 l0.03 \l00.0

The table and flotation products showed such a marked separation that no attempt was made t clean the concentrates nor to reduce the feldspar content of the tailings. However, this might be a desirable step in the preparation of more In adcessfully used'in these separations might be called cationic reagents, by which is meant organic reagents that ionize to give small anions and large complicated cations. The latter probably tend to be adsorbed on acidic mineral surfaces thus filming them with a greasy substance that repels water and encourages attachment of air bubbles selectively. The selectivity in turn is dependent upon the addition of hydrofluoric, fluosilicic, fluoboric acids or their derivatives.

While I have described above certain preferred examples illustrating various applications of my invention, such examples and application are best illustrative of my invention and are not to be construed as restrictive either in this description or in the appended claims. In face the separation is also adaptable to the separation of other silicate minerals such as kyanite from quartz in which treatment with the hydrofluoric acid the normal flotation or table concentration with a cationic reagent like lauryl amine hydrochloride is reversed. Thus such changes may be made in the practices of my invention as are desirable to adapt my method to special applications, and the invention comprehends all variations reasonably derived from my disclosures and embodying the principles thereof.

The foregoing may be briefly summarized as follows:

acidic mineral feldspar (1) Preparing feldspapquartz ores kyanite concentration froth flotation separation film flotation separation agglomerate separation (2) For suitable filming agents flotation reagents agglomeration agents cationic concentrating reagents (4) Before adding or in the presence of (5) And separating by steps under (2).

Accordingly, as used in the following claims, the term ores of the class described is to be interpreted as including acidic minerals such as feldspar, feldspar-quartz and kyanite; the term flotation is to be interpreted as covering concentration by any of the usual methods such as froth flotation separation, film separation, and agglomerate separation; and the term hydrofluoric acid containing complexes of polyvalent elements to be construed as covering hydrofluoric acid containing such elements as fluosilicic acid, fluoboric acid and fluotitanic acid, or as contemplating hydrofluoric acid entirely combined in the polyvalent form such as fluosilicic acid, or salt or derivatives of the above acidified with mineral acids; and the term concentrating reagents" is to be construed as comprising suitable filming agents, flotation reagents, agglomerate reagents or cationic concentrating reagents.

I claim as my invention: Y

1. The process of separating aluminous silicate minerals of the group consisting of feldspars and kyanite from comminuted mixtures thereof with quartz consisting in forming a slurry of the mixture with water, a cationic flotation reagent yielding long chain cations containing from twelve to nineteen carbon atoms, and a modifying agent consisting of hydrofluoric acid in which may have been dissolved multivalent, metaloxides from traces to almost complete neutralization of the acid, and separating the said aluminous silicate minerals by flotation.

2. In the separation of finely divided feldspar and quartz, the step of floating oil the fine feldspar by lauryl amine hydrochloride and an acid containing fluorine as part of its molecular structure, in an acid circuit, substantially as described.

3. In the separation of finely divided feldspar and quartz, the step of floating off the fine feldspar by trimethyl cetyl ammonium bromide and an acid containing fluorine as a part of its molecular structure, in an acid circuit, substantially as described.

4. In the separation of finely divided feldspar and quartz, the step of floating off the fine feldspar by a cationic reagent, yielding long chain cations containing from twelve to nineteen carbon atoms, and an acid containing fluorine as a part of its molecular structure, in an acid circuit, substantially as described.

5. In the separation of finely divided kyanite and quartz, the step of floating off the fine kyanite by lauryl amine hydrochloride and an acid containing fluorine as a part of its molecular structure, in an acid circuit.

6. In the separation of finely divided kyanlte and quartz, the step of floating off the fine kyanite by trimethyl cetyl ammonium bromide and an acid containing fluorine as a part of its molecular structure, in an acid circuit.

7. In the separation of finely divided kyanite and quartz, the step of floating oil the fine kyanite by a cationic reagent yielding long chain cations containing from twelve to nineteen carbon atoms and an acid containing fluorine as a part of its molecular structure, in an acid circuit.

8. A process of separating quartz-containing ores of the group consisting of feldspar and kyanite ores which consists in forming an acid slurry of the comminuted ore with water, an acid containing fluorine as a part of its molecular structure, and a cationic flotation reagent yielding long chain cations containing from twelve to nineteen carbon atoms, and effecting flotation thereof.

9. In a process of separating feldspar ores by flotation, the step of conditioning a wet pulp of the ore by incorporating therein an acid containing fluorine as a part of its molecular structure and a cationic filming agent yielding long chain cations containing from twelve to nineteen carbon atoms.

10. A process of separating ores of the ,class described, which consists in forming a wet pulp of the ore with at least oneof the acidic selectors from appended group A, and at least one of the agents from appended group B, and thereafter effecting separation by at least one appropriate operation of those of appended group C:

group A (acidic selectors) acids containing fluorine as a part of their molecular composition selected from the group consisting of hydrofluoric acid, impure hydrofluoric acid, fluosilicic acid, fluoboric acid, fluotitanic acid, and salts thereof in combination with mineral acid;

group B (agents) cationic reagents yielding long chain cations containing from twelv to nineteen carbon atoms;

group C (operations) froth flotation, agglomerate and film flotation.

ROBERT GIBSON OMEARA.