US2322789A - Concentration of sylvinite ores - Google Patents

Description

Patented June 29, 1943 CONCENTRATION OF SYLVINITE ORES Allen T. Cole and James B. Duke, Mulberry, and Karl F. Schilling, Lakeland, Fla., assignors, by mesne assignments, to Minerals Separation North American Corporation, New York, N. Y., a corporation of Maryland No Drawing. Application June 2, 1942, Serial N0. 445,450

, 14 Claims. (01. 209166) This invention relates to the concentrating, or separation of the values from soluble ores. More particularly, it relates to the separation of sylvite (potassium chloride-K01) from a saturated solution of the soluble constituents of sylvinite ores such, for example, as those found in the Carlsbad district of New Mexico.

The invention resides in improved methods of effecting the separation of the desired sylvite from such ores by froth flotation, skin flotation, agglomeration tabling and other methods involving wet stratification with the use of appropriate agents which effect the separation of the sylvite from the other ore constituents.

It is already known that sylvite can be recovered from a saturated solution of the soluble constituents of sylvinite ore in accordance with well-established concentration operations by using as a collector an aliphatic amine containing a straight chain hydrocarbon group of at least 7 carbon atoms, or the salts of such amines resulting from their combination with water-soluble acids.

The general objects of the present invention are to produce concentrates of the desired sylvite which are of high commercial grade, with high percentages of recovery, with economy in the use of reagents and with reliable and easily controlled operation of the plant. These objects are attained by the processes embodying the present invention which are hereinafter described.

The methods of the present invention are the result of the discovery that greatly improved results, as to grade and recovery of the desired sylvite and as to control of operations, can be obtained by the use, in conjunction with the aforesaid straight chain alkyl amines used as collectors, of dextrin as an auxiliary agent.

The straight chain alkyl amines useful as 001- lectors for sylvite, the action of which is improved by the concurrent use of dextrin as an auxiliary agent, include the following aliphatic primary amines: n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecyiamine, n-tetradecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, and noctadecenylamine. The lower members of this series may be added to the ore pulp in the form of the free base or as the salts formed by their combination with acids which are themselves relatively devoid of surface active properties, such, for example, as hydrochloric acid, nitric acid, acetic acid, etc. The higher members of the series, being much less soluble, are generally used in the form of their more soluble salts.

These amine collectors may be used individually or as mixtures, The mixtures need not necestheir salts but may also contain varying proportions of aliphatic secondary and tertiary amines or their salts, such as are commonly found in commercial products. For example, the product of Armour and Company sold under the designation Am.Ac.118DC is very suitable and is understood to consist of approximately 73% monooctadecylamine acetate, about 24% mono-hexadecylamine acetate, together with small quantities of secondary and tertiary amine acetates. Another suitable commercial product is that sold by E. I du Pont, de'Nemours & Company, Inc., as D. P. 243" which is a 50% aqueous paste of technical laurylamine hydrochloride understood to contain approximately 18% octylamine hydrochloride, 10% decylamine .hydrochloride, 55% laurylamine hydrochloride, 17% myristylamine hydrochloride, and traces of secondary and tertiary amines.

.The term dextrin is employed herein and in the claims as indicating the partial degradation and/or hydrolytic products of starch. It may be prepared from potato, corn, cassava, tapioca, rice, or wheat starch by heating it alone or in the presence of a catalyst, by heating an aqueous starch suspension with an acid or by conversion with enzymes. Excellent results have been obtained with either the white or yellow dextrins of commerce, made from corn and potato starches respectively. The dextrins are preferably used in the form of aqueous solutions or suspensions.

In practicing the methods of the present invention, desliming of the sylvinite ore is desirable; and it is also sometimes desirable to add a frothing agent, such as pine oil, in addition to the collector and the dextrin, when the desired mineral is to be concentrated by froth flotation, or a petroleum oil such as fuel oil when concentration is effected by tabling.

The following contrasting examples giving the results obtained in concentrating sylvite, without and with the use of dextrin as an auxiliary agent in conjunction with a straight chain alkyl amine collector, illustrate the advantages obtained "by employing the methods of the present invention; but the invention is not to be construed as being limited to the details hereinafter described.

EXAMPLE I.--No ,dextrin.Sylvinite ore from Carlsbad, New Mexico, wascrushed so that it would pass through a IO-mesh screen, and was made into a pulp of about 20% solids with a saturated solution of ore constituents. Reagents, as hereinafter specified, were added to this pulp, the pulp was agitated about 10 seconds to distribute the reagents and flotation was then eflected. The first or rougher froth concentrate was returned to the flotation machine, diluted and refloated. This was repeated on the second froth concentrate. The reject of the first flotation operation was final tailings. Rejects of the second and third flotation operations were middlings to be returned to the flotation circuit and further values recovered therefrom. The reagents used were n-heptylamine acetate (introduced as a aqueous solution) 1.00 lb., and pine oil 0.2 lb., both to the ton of ore treated. Results were as follows:

EXAMPLE II.-With yellow dextrin-This operation was identical with Example 1, except that dextrin was employed as an auxiliary agent. 0.8 lb. per ton of yellow dextrin was added to the pulp in the form of a 5% aqueous solution, in addition to the reagents used in Example I. The results were as follows:

Product Weight K01 ggg Per cent Per cent Feed 100. 0 30. 6 100.0 1 26.8 84.6 74. 3 3. e 21. 9 2. o 10. 3 10. 9 3. 7 56.0 9. 3 ,17. o 3. a 22.1 2. 4

It will be noted that the use of the dextrin in conjunction with the other reagents improved the grade of concentrate by 13.3% (84.6% KCl when dextrin was used, as against 71.3% KCl Without it) and increased the recovery by 31.2% (74.3% as against 43.1%).-

EXAMPLE III.-No dextrin-This test was made on a different sample of ore, also from Carlsbad, and will serve as a basis of comparison for the tests of Examples IV and V. The ore was prepared in the same manner as in Example I and subjected to the same concentrating operations. The reagents used were the Am.Ac.1180-C described above, a commercial amine acetate product, in the amount of 0.6 lb. and pine all 0.3 lb., both per ton of ore. Results were as follows:

K01. Product Weight KCl recovery Per cent Per cent Feed 100. 0 33. 1 100.0 Concentrate 17. 0 92. 4 47. 4 Middling 2. 7. 7 86. 0 20. 1 Middling i 9. 2 54. 3 15. 3

ailing 62. 6 7. 6 1.4. 4 Slime 3. 6 29. 0 2. 8

EXAMPLE IV.-With white dextrin-The ore, procedure and reagents were the same as in Example III, except that there was added to the pulp 1.0 lb. per ton of white dextrin in the form of an aqueous solution or suspension. The results were as follows:

Product Weight KC] gg Per cent Per cent Feed 100. 0 32. 0 100. 0 Concentrate 21. 3 97.0 64. 4 Mlddling 2 5. 1 93. 6 14.9 Middling 1. 5. 4 53. l 8.9 Telling 63.6 4. l 8.4 Slime .Q... 4.6 23.8 3.4

By comparison with Example III it will be seen that the addition of the dextrin increased grade by 4.6% and recovery by 17%.

EXAMPLE V.With yellow. dextrin-The ore, procedure and reagents were the same as in Example III. except that there was added to the pulp 1.0 lb. per ton of yellow dextrin in the form of an aqueous solution. The results were as follows:

KC] Product Weight K01 recovery Percent Percent Feed 100. 0 32. 6 100. 0 Concentrate 27. 5 96. 2 81. 5 Middl ng 2 l. 8 82. 4 4. 4 Middhng 1. 3. 5 30. 3 3. 4 Telling. 62. 8 3. 8 7. 3 Slime 4. 4 23. 9 3. 4

Product recovery EXAMPLE VII.-With yellow dextrin-The ore, procedure and reagent were the same as in Example VI except that 0.8 lb. per ton of ore of yellow dextrin was added as an aqueous solution. Results were as follows:

KCI Product Weight KCl recovery Percent Percent By comparison of Examples VI and VII it will be seen that the addition of the dextrin increased recovery by 27.5% with a very slight drop in grade of 1.9%.

EXAMPLE VIII.--No dextrin-This example and the next illustrate the beneficial effect of using dextrin as an auxiliary agent in the recovery of sylvite by table concentration methods. The ore was from the same source as that used in Examples I and II and was first reduced to particle sizes ranging from about minus 6 to about plus 35-mesh and then partially deslimed. It was then made up to a pulp in which the ratio of brine to ore was 1:1.88 by weight and conditioned with the reagent for about one minute. The sole reagent was "Am.Ac.1180C,' 0.5 lb. per ton of ore. The conditioned pulp was diluted and fed to a shaking table with a saturated aqueous solution of soluble ore constituents. The sylvite concentrate was recovered at the side of the table and the rejected constituents went off at the end of the table. The results were as follows:

Product Weight KC] recovery cent EXAMPLE IX.With yellow dextrin.-The ore, procedure and reagent were the same as in Example VIII except that 0.4 lb. per ton of ore yellow dextrin was added as an aqueous solution. Results were as follows:

x01 Product Weight KCl recovery Percent Percent Feed 100.0 27.3 100.0 Concentrate 25. 9 92. 7 87. 9 fiddling 2.5 326 2.9 Middling l... 5. 3 6. 5 1. 1 Telling A 65. 5 3. 2 7. 7 Slime 0.8 9.0 0.4

pended claims, the invention may be practiced comprises subjecting said pulp to a concentrat- 7 ing process employing a collector selected from the group consisting of aliphatic amines con taining a straight chainhydrocarbon group of at least 7 carbon atoms and their soluble salts formed by their combination with acids which are relatively devoid of surface active properties,

which resides in distributing in said pulp a useful amount of an auxiliary agent; consisting of dextrin, and thereafter subjecting the pulp to a separation treatment to remove the desired sylvite.

2. A method as set forth in claim 1, wherein the pulp is formedfrom sylvinite ore and a substantially saturated aqueous solution ofthe soluble ore constituents.

3. A method as set forth in claim 1, wherein the sylvinite ore is substantially deslimed before the collector and the auxiliary agent are added.

' 4. A method as set forth in claim 1, wherein the separation treatment is a froth-flotation treatment in a froth-flotation machine.

5. A method as set forth in claim 1, wherein the separation treatment is an agglomeration tabling treatment.

6. A method as set forth in claim 1, wherein a frothing agent is used in conjunction with the collector and auxiliary agent and the separation of the sylvite is effected by froth-flotation.

'l. A method as set forth in claim 1, wherein a petroleum oil is used in conjunction with the collector andauxiliary agent, the sylvite ag lomerated and the agglomerates separated.

8. A method as set forth in claim 1, wherein the auxiliary agent is com dextrin.

9. A method as set forthin claim 1, wherein the auxiliary agent is potato dextrin.

10. A method as set forth in claim 1, wherein octadecylamine acetate is used as the collector.

11. A method as set forth in claim 1, wherein n-heptylainlne acetate is used as the collector.

12. A method as set forth in claim 1, wherein laurylamine hydrochloride is used as the collector.

13. A method as set forth in claim 1, wherein octadecylamine acetate is used as the collector in conjunction'with a frothing agent and separation is effected by froth-flotation to remove the sylvite.

14. A method as set forth in claim 1. wherein octadecylamine acetate is used as the collector in conjunction with a petroleum oil and separationds effected by agglomeration tabling treat- .ment to remove the sylvite.