CA1176765A - Branched alkyl ether amines as iron ore flotation aids - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

This invention relates to the use of primary ali-phatic ether amines as silica collectors in the concentra-tion of minerals by the froth flotation process. More specifically, it relates to the use of mixtures of primary methyl branched aliphatic ether amines and the partially neutralized salts thereof as flotation reagents. In fur-ther aspect, it relates to the use of mixtures of 3-iso-octoxypropyl monoamine and 3-isodecoxypropyl monoamine or of 3-isononyloxypropyl monoamine and its ethoxylated and propoxylated derivatives and/or the partially neutralized acetate salts thereof as collectors for silica in the beneficiation of oxidized taconite ores.

Description

.~7~'76~

BRANCHED ALKYL ETHER AMINES AS IRON ORE FLOTATION AIDS
1 The invention relates to the use of primary

2 branched aliphatic ether monoamines as silica collectors

3 in the concentration of minerals by the froth flotation

4 process. More particularly, it relates to the use of partial acid salts of primary branched alkyl ether as 6 cationic silica collectors in froth flotation of iron ore.
7 Froth flotation is a common process applied in 8 the art of separating or concentrating minerals from ore 9 or the like. Briefly, the flotation process usually com-prises grindinq crushed ore, classifying the ground ore in 11 water, treating the classified ore by flotation to concen-12 trate one or more minerals while the remaind~r of the min-13 erals of the ore remain behind in the water pulp, thicken-14 ing and filtering the separated concentrate and thereafter treating the same for ultimate use of the separated min-16 erals. In carrying out the flotation step, a collector is 17 added to the ore dispersed ln the water and air is intro-18 duced into the pulp to form a froth, and the froth, con-19 taining those minerals that are wetted by the col]ector and have an affinity for air bubbles, is withdrawn.
21 A host o selective collecting asents have been 22 developed that are used for forming water-repellent, air-3 avid surfaces on one mineral or a class of minerals. These 4 collectors are anionic or cationic, and while many of them have been used satisfactorily, they often are limited by 26 their solubility and handling characteristics, selectivity, 27 effectiveness, stability, cost, etc.
28 In recent years, the enrichment of non-magnetic 29 taconite iron ore deposits by a selective flocculation/
desliming process, followed by froth flotation, has become 31 an important commercial process. The application o this 32 process to a large ore body located on the Marquette Range 33 in Michigan (the Tilden Mine) is described in a paper:
34 Villar, J.W. and Dawc, G.~ c Tilden Mine- a New Processing Technique for Iron 36 Ore", Mining Congress Journal, October, 1975, 37 Vol. 61, No. l0, pgO 40-48.

'765 1 The process utilizes a cationic flotation system 2 ~ollowing the selective flocculation/desliming step. The 3 purpose of the cationic flotation system is to remove sili-4 ca from the deslimed ore to produce an iron ore concentrate of commercial qrade.
6 The cationic flotation system employs an amine 7 collector. The principal amine collector utilized in the 8 Tilden process has ~een an ether amine of the following 9 general structure:
H H H H
11 Alkyl-O-C-C-C-N

14 where Alkyl-O is derived from a mixture of normal alcohols consisting predominantly of Cg and Clo carbon number alco-16 hols. In use, the amine is typically partially neutralized 17 (~30 percent) with acetic acid to improve water dispersi-18 bility 19 Other mono ether amines offered commercially for iron ore flotation are products where Alkyl-O is deri~ed from 21 normal Clo alcohols, methyl branched Clo alcohols, normal 22 Cl2-Cl4 alcohols, and normal Cl6-Cl8-C22-C26 alcohols-23 Other products which have been mentioned in the patent 24 literature include products derived from normal C6,C7,Cg, C9~Cl0~Cll~Cl2~Cl3~Cl4,Cls, etc. alcohols and various iso 26 Cg alcohols (see U.S. Patent 3,363,758 for other starting 27 alcohols).
28 Other products known for cationic flotation of 29 iron ores include fatty amines, fatty beta-amines, various ether diamines (see U.S. Patents 3,363,758 and 3,404,165) 31 and, more recently, blends of alkyl amines/mono ether 32 amines, and alkyl amines/amino ethers (see U.S. Patent 33 4, 168,227) .
34 The collector used in a cationic flotation ~ro-35 cess Eor iron ore is desired to achieve many, sometimes 36 conflictinq objectives. These requirements are outlined as 37 follows:

~7~7~5 1 l. Produce an Iron Ore Concentrate of Acceptable Quality 2 The final product must contain a sufficiently 3 high iron content (generally 60+ weight percent Fe) and not 4 exceed a given silica content to meet commercial standards.
It is desirable that. silica contents not exceed 5-6 weight 6 percent SiO~. In some cases, high purity (2-3 weight per-7 cent SiO2) iron concentrates are required.
8 2. Recover the Maximum Quantity of Iron Consistent with g Acceptable Quality Iron recovery is of major economic importance to 11 the plant operation. For example, improving iron recovery 12 by l weight percent from a crude ore assaying 35% Fe in-13 creases the return per ton by about 25 cents.
14 3. Achieve Acceptable Results with a Variety of Iron Ore Types 16 Variations occur in the specific type of iron ore 17 encountered in day-to-day minlng operations. A given de-18 posit of ore may vary significantly in the amount of de-19 sired contained iron ore minerals (e.g., martite, hematite, magnetite, geothite, etc.) and in undesired gangue ~quartz, 21 clays, etc.). Commercial iron ore technology does not per-22 mit controlling the precise composition of the crude ore 23 being fed to the concentrator (although attempts are made 24 to minimize gross changes through control of mining and ore blending operations). Thus, a successful collector must 26 give acceptable results with the normal commercial varia-27 tions in ore types fed to the concentrator.
28 4. Be Sufficiently "Persistent" to Yield Acceptable Re-29 sults Through Several Stages of Froth Flotation Sharp separations between the undesired silica 31 mineral particles and the desired iron-containing mineral 32 particles are not obtained in a single stage of froth flo-33 tation. Thus, in commercial practice, to remove enough 34 silica in the Rougher Flotation cells to achieve commer-cial purity iron ore concentrate in the underflow, consid-36 erable amounts of iron ore are also removed in the froth.
37 Loss of this iron would make the process uneconomic. Thus, ~7~:;'7i~iS

1 the froth product from the Rougher Flotation cells is sub-2 jected to several subsequent cleaner froth flotation stages 3 to further separate the desired iron ore ~rom the undesired 4 silica.
In theoLy, collector could be a~ded at each stage 6 of Rougher and Cleaner Eroth flotation. Elowever, in com-7 mercial practice, collector is often added only to the 8 Rougher cells. Even i additional collector is added at g some stage of the cleaning process, this causes compllca-tions in process control.
11 As a practical consequence, a commercial collec-12 tor must "persist" (i.e., continue to cause the silica 13 mineral particles to float) through several stages of 14 cleaner flotation.
It should be noted that this requirement for a 16 successful collector has heretofore not been recognized in 17 iron ore flotation as a specific property of a collector 18 which should be determined.
19 5. Require Minlmum Quantities of Collector to Achieve Acceptable Operations 21 While costs of collector are relatively small 22 versus, for example, the value of improved iron recovery 23 and/or the cost of unsatisfactory operations, these collec-24 tor costs are still an important operating cost. It is general commercial practice to minimize the amount of col-26 lector used. Thus, collectors which achieve satisfactory 27 operations at minimum treating rates are desired. Stated 28 another way, a collector which gives a relatively flat 29 dose-response curve is preferred, i.e., when the response (~ Fe recovered of target quality) is plotted as a result 31 of increasing the dose (pounds of collector per long ton 32 of ore) the slope should be small, optimally zero) over a 33 wide range.
34 6. Continue to Achieve Equal or Improved Response at High Dosages 36 When plant operations become more difficult (for 37 example, from changes in ore quality, lower water tempera-~L~'76'7~S

1 tures, and other factors), it is necessary to increase col-2 lector dosage to attempt to achieve target quality froln 3 the froth flotation operations. With some collectors, an 4 increase of dosage results in a loss in selectivity be-tween silica and iron ore, resulting in a drop in Fe re-6 covery, i.e., the slope of the response - dosage curve 7 referenced in (5) is negative at high dosages.
8 7. Continue to Achieve Good Performance Under Cold Weather 9 Conditions On the North American Continent, major iron ore 11 deposits are located in Michigan, Minnesota, and Canada.
12 It has been found that performance of the cationic flota-13 tion process becomes poorer when water temperatures drop, 14 even though the specific mechanisms which cause this effect are not well understood. It is obviously desirable that a 16 collector suffer the minimum drop in performance under cold 17 water flotation.
18 It is also desirable, though less important, that 19 a collector have good physical handling properties under cold weather conditions in its concentrated form. Obvi-21 ously, lower viscosities and lower freezing points offer 22 advantages in product unloading, pumping, and storage.
23 Energy is saved through minimizing the need for heating the 24 product.
The preparation of aliphatic ether primary amines 26 is not only set forth in said U.S. Patent 3,363,758 but 27 also in numerous earlier publications including U.S.
28 Patent 2,372,624.
29 It is an object of the invention to provide a 3~ cationic collector reagent which performs better than known 31 collectors in meeting the foregoing requirements for the 32 concentration of mineral ores, particularly for iron ores.
33 SUM~lARY OF THE INrVENTION
34 It has been discovered that a partial acetate salt 35 of a mono ether monoamine manufactured from a blend of 50 36 parts by weight of methyl branched octyl alcohol and 50 37 parts by weight of methyl branched decyl alcohol provides ~"

.. . . . .

~t76~7~l5 1 an improved cationic collector reagent for the flotation 2 concentration of finely ground and deslimed iron ore con-3 centrates.
4 Within the preferred concept of this invention, the methyl branched C~ and Clo alkyl ether monoamine and 6 partially neutralized acid salts thereo~ used to form the 7 surprisingly useful cationic collector blends can be repre-8 sented by the general ~ormulae:
9 R-o-cH2-cx2-cH2-N~2 ~ or 11 (R-O-CH -cH2-CH2-NH3) (X) 12 wherein R represents a mixture of methyl-branched aliphatic t3 radicals having predominantly 8 or predominantly lO carbon 14 atoms and X represents a water solubilizing mono or poly-valent anion.
16 Within the broad concept of this invention the 17 mixture of branched C8 and Clo alkyl ether monoamines and 18 the corresponding acid salts Eound to be surprisingly use-19 ful as cationic collector blends can be represented by the general formula: ~
21 [R O R NH2]l _n [ 3 n [X]n 23 where R and X are as previously defined, R' is an alkylene 24 group having from 2 to 5, preferably 3, carbons, and n is zero to l, preferably O.l to 0.5, optimally 0.3.
26 It al50 has been discovered that an cthcr mono-27 amine derived from isononyl alcohol provides an improved 28 cationic collector reagent for the flotation concentration 29 of ~inely ground and deslimed iron ore concentrates. In actual practice, and to facilitate water dispersibility, 31 said isononyl ether monoamine is often partially neutral-32 ized, i.e. up to 80~ with an acid, preferably acetic acid, 33 forminq a partial acid, preferably acetate, salt.
34 These compounds can be represented by the general formulae:

;t7~5 1 Rll-o-C~l2-CH2-CH2-NH2 2 or 3 (R"-0-CH2-CH2-CH2-NH3)~ (X) 4 wherein R" represents anv or all of the isomers of the iso-nonyl radicals and X represents an anion such as acetate.
6 It has also been ~ound that commercially avail-7 able isononyl alcohol can be used. Commercially produced 8 isononyl alcohol consists predominantly of isomeric di-9 methyl heptanols and trimethyl hexanols, together with other isononyl alcohol isomers and also contains some lower 11 boiling (isooctyl and isoheptyl alcohols) and higher boil-12 ing (isodecyl alcohol) components.
13 It is therefore within the concept of this inven-14 tion to use as little as 30~ of the isononyl derivative together with as much as 70~ of isooctyl and/or isodecyl 16 derivatives or to use the isononyl derivative wherein at 17 least 70% oE the alcohol building block is isononyl alcohols, 18 the remaining 30% or less bein~ comprised of isooctyl or 19 isodecyl alcohols.
DETAILED DESCRIPTION OF TRE INVENTION
21 According to an article appearing in Mining Maga-22 zine January lg77, pages 25-31, entitled "Cationic Silica 23 Flotation", mineral separation by froth flotation requires 24 the use of chemical additives which can be categorized by function into three general types. They are: (l) the col-26 lector or flotation reagent which imparts the hydrophobl-27 city to one mineral species, (2) the frother which lowers 28 the aqueous surface tension to produce a semi-stable foam 29 at the air-water interface, and (3) the modifiers or auxi-liary reagents which are used to enhance the selective ad-31 sorption of the collector to a specific mineral surface 32 and include, in the case of the cationic silica flotation, 33 depressants, dispersants, and ph regula~ors.
34 The ether monoamine collectors of the invention are by nature cationic surfactants. The amino groups 36 (-NH2) attach to silica and silica materials, providing the 37 required selectivity for flotation, while the ether link-6'7~;,S

ages (R-O-C) give these materials relatively low melting 2 points and good dispersibility. Although useful irl free 3 amine form, the collectors of the invention may be partial-4 ly to fully neutralized for direct dispersion in water.
The primary methyl-branched ether amines and par-6 tially to fully neutralized salts thereof preferably em-7 ployed to obtain mixtures useful in the practice of this 8 invention can be represented by the general formulae:
(a) R-o-cH2-c~l2-cH2-NH2 AMINE
Where R- is a mixture of methyl-branched aliphatic radicals 11 having predominantly 8 or l0 carbon atoms. The number of 12 methyl radicals in said branched aliphatic radical may be 13 from l to 5, perferably 2 or 3.
14 or (b) (R-O-CH2-CH2-CH2-NH3) ~ (X)~ PARTIP~LL~-NEUR~LIZED

17 Where R- is as described in formula (a). X may be any 18 water solubilizing mono or pol~valent anion such as fluo-19 ride, chloride, iodide,bromi~e,acetate or other organic anion such as oxalate, sulfonate, salicylate and the like, phos-21 phate, borate, nitrate, perchlorate, sulfate, etc.; the preferred 22 anion being acetate.
23 The de3ree to which the aliphatic ether amine may be neu-24 tralized is such that water dispersibility is sufficient to provide adequate dispersion in the flotation 26 mixtures while remaining liquid, said degree of neutrali-27 zation being from 0 to l00 mole percent, preferably in 28 the l0 to 50 percent range.
29 The mixtures of methyl-branched alkyl ether amine acetates which may be used in this invention may be 31 prepared from the corresponding methyl-branched, prefera-32 bly oxo, alcohols or mixtures oE alcohols by the well-33 known cyanoethylation reaction, subsequent catalytic re-34 duction, and neutralization with the conjugate acid of the desired anion.
36 The "oxo" process is well known for the produc-37 tion of alcohols by passage of olefin hydrocabon vapors 7~7~

l over cobalt catalysts in the presence of carbon monoxide 2 and hydrogen.
3 The th~s prepared methyl-branched alkyl ether 4 amine acetates are liquids which may have low pour points, said low pour point being a desirable property because S this eliminates the need for heating storage tanks during 7 cold weather.
8 R- has been defined above as a mixture of methyl 9 branched, predominantly C8 and Clo aliphatic radicals.
As used herein, a mixture means that in a useful system 11 for this invention at least a sufficient amount of the Cg 12 or Clo component is present such that the peculiar bene-13 ficial properties of the minor component are perceptible 14 in the collector activities. The weight ratio of the Cg aliphatic component to the Clo aliphatic component ranges 16 generally from l to 4 to 4 to l, preEerably ~rom l to 3 to 17 3 to l, optimally l to l. Since it is desirable to use an 18 oxo alcohol as the source of the C8 and Clo componen~s, 19 the phrasing, predo~linantly C8 and predominantl~ Clo, is appropriate since each oxo alcohol contains alcohols of 21 chain lengths other than the designated isooctanol or 22 designated isodecanol.
23 The amount of ether monoamine collector blend 24 used in the froth flotation process will vary and be de-pendent upon such factorg as the type of ore being treated, 26 the amount of mineral to be collected, the degree of sub-27 division of such minerals, the deqree of separation de-28 sired, the deqree of neutralization and the particular 29 weight ratio of the C8 and C10 components of the ether monoamine blend when such blend is employed. Functionally 31 expressed, the amount of ether amine acid salt reagent 32 used in such froth flotation process will be that sufficient 33 to achieve a desirable separation. Generally, the amount 34 of ether amine acid salt used will be 0.05 to 2 pounds, preferably O.l to 0.3 pound, per tone of ore.
36 The ether amine acid salt reagent can be employed 37 as a solution or dispersion in water or other solvent ~. .

67~

1 and introduced into the ore pulp as such without prior 2 conditioning or can be conditioned with the ore pulp prior 3 to the actual concentration operation. In addition, the 4 reagents of this invention can be used in conjunction with other conventional treating agents such as activators, 6 frothing agents, depressing a~ent, dispersing agents, etc.
7 In carrying out the practice oE this invention, 8 the generallywell known technique of the froth flotation g process is used. ~riefly, the ore, or a concentrate of the ore, is ground and mixed with water to form a pulp.
11 The pulp is placed in a suitable flotation cell or vessel 12 provided with an agitator. Air is introduced into the 13 pulp by means of a sparger and passes through the pulp.
14 The ~roth that is formed is skimmed off or allowed to overflow. The silica floats away from the froth, leaving 16 the mineral concentrate behind. In this manner, the silica 17 or siliceous material is separated from the desired miner-~8 al. Although this invention is particularly applicable in 19 removing silica from iron ore, such as magnetite, it can be used in concentraking any silica-containing minerals 21 or ores, such as hematite, goethite, phosphate rock, etc.
22 The following examples further illustrate the 23 advanta~es and objects of this invention, but the various 24 reagents, conditions of treatment, and other details re-cited in these examples should not be construed to unduly 26 limit this invention.

28 Illustrative of the preparation of the alkyl 29 ether monoaminesand their respective partially neutralized salts, utilized in the collector evaluations hereafter re-31 ported, is the following:
32 An equal weight mixture of oxoisooctanol and 33 isooxodecanol was reacted with a slight molar excess of 34 acrylonitrile in the presence of sodium methylate over a four hour period at a temperature ranging from 25 C to 36 40 C.
37 The sodium methylate in the reaction mixture was 7~'~6~, 1 neutralized with acetic acid, followed by filtration of 2 the mixture through filter paper while under reduced pres-3 sure.
4 EIydrogenation was carried out under pressure with a mixture of ammonia and hydrogen in the presence of 6 Raney nickel at from 300 to 600 psig at 140 C for f~om 4 7 to 5 hours. The amine was purified by filtration after 8 which 0.3 mole of acetic acid for each mole of ether a-g mine was added with stirrinq while ~eeping the temperature below 43 C.
11 Aside from commercially available ether mono-12 amines (clearly reEerenced hereafter) the various amines 13 reported herein were similarly produced.

Heretofore it was believed that a given collect-16 or composition was either acceptable or unacceptable for 17 a given ore body. Little thought was given to the matter 18 of ore-body variability and how flotation collector struc-19 ture might be optimized for a specific ore-body subtype.
It has been found that variations occur in the 21 specific type oE iron ore encountered in day-to-day mining 22 operations within a given ore body. Two different sub-23 types of Martite Ore from a single commercial iron ore 24 mining site have been isolated and characterized as seen from Table I.
26 TA~3LE I

28 C~IARACTE~IZATION Of TWO SUSTrPES O,f, 29 I~ARTITE O~E ',IITHIN THE SAME GENERAL ORE BOOY

Ore "A" _ Ore "B"
332 General C:onst1tuentsMartit2 and ~uartz Martite. Ouart~, 33 o X Re 35.9 33.6 34 o ~ siO~ 46.3 47.s ~ X Loss on ignition 0.67 2.33 36 o S Goe~hite in ore (based on LOI data) 6.0 2û.0 37 ~ Goethite as a ~ o~ total contained fe lO.O 38.0 -'Y6~

1 While both subtypes of ore can be separated to 2 some extent through the use of a commercially-availa~le 3 linear-based ether amine collector, the folLowing sur~ris-4 ing results were obtained:
(a) As shown in Table II, for Ore Subtype "A", 6 a 50/50 weight percent blend of methyl branched 3 isode~
7 coxypropyl monoamine aceta~e and methyl branched 3 iso-8 octoxypropyl monoamine acetate yielded s~bstantially bet-g ter iron recovery at e~uivalent grade than did a series of amine collectors. These collectors, ranked in order of 11 recovery effectiveness, are as follows:
12 1. Methyl-Branched iso C8/C10 oxypropyl amine 13 ac0tate.
14 2. Methyl-Branched isodecyl oxypropyl amine acetate.
16 3. Linear Cg/Clo oxypropyl amine acetate.
17 4. Methyl-Branched isooctyl oxypropyl amine 18 acetate.
19 5. Commercially-available linear C8/Clo oxypro-pyl amine acetate (sold as MG-98A3 by Sherex 21 Chemical Co. of Dublin, Ohio, a Division 22 of Schering Co.) 23 6. Linear octyl oxypropyl amine acetate.
24 7. Linear decyl oxypropyl amine acetate.

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1 (b) Ho~ever, as shown in Table III, for Ore 2 Subtype "B", the best collector from the recovery stand-3 point proved to be a Methyl-Branched C8 oxypropyl amine 4 acetate. The seven collectors, ranked in order of ef fectiveness, are as follows:
6 1. Methyl-Branched isooctyl oxypropyl amine 7 acetate.
8 2. Linear octyl oxypropyl amine acetate.
9 3. Methyl-Branched C8/C10 oxypropyl amine ace~ate 4- Linear C8/C10 oxypropyl amine acetate.
11 5. Commercially-available linear C8/C10 oxy-12 propyl amine acetate.
13 6. Methyl-Branched isodecyl oxypropyl amine 14 acetate.
7. Linear decyl oxypropyl amine ace,take.

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1 From these data it is suggested that the optimum 2 collector reagent from an iron recovery standpoint varies 3 with the particular ore subtype(s) within an ore body.
4 Thus for effective recovery, it would be useful to vary the character of the collector as the nature of the ore 6 subtype(s) vary during the processing of the ore body.

8 It has been further determined that another 9 property, that of collector persistence, is critical in the actual performance of a collector in a multi-stage 11 flotation process. In Tables II and III, persistence 12 indices are shown for each collector at the appropriate 13 amine dosage when used upon Ores "A" and "B". Laboratory 14 and actual plant studies have shown that a persistence index of at least 6.5 is necessary for a collector to ade-16 ~uately maintain flotation through a four-stage flotation 17 process-18 Persistence index (as used herein and in ~ables 19 II and III) is defined as the ratio of the weight of material floated in the# 4 flotation cleaner sta~e to the 21 weight of material not floated in that sta~e. Therefore, 22 higher persistence indices denote "stronger" flotation 23 properties in the latter flotation stages.
24 It will be noted that in Ta~lë~IIr collectors 4, 5, and 9 do not exhibit acceptable persistence for the 26 Type ~A~ ore 27 Similarly, in Table III, collector 1, while 28 rated best from the Fe recovery standpoint, does not meet 29 the minimum persistence criteria. Therefore, despite the superiority of collector 1 from a recovery standpoint, its 31 performance in a four-stage flotation process would pro-32 bably not be optimum. However, this does not preclude the 33 use of reagent 1 (the Methyl-Branched iso C8 oxypropyl 34 amine acetate) in a multi-point addition flotation circuit treating the Type B ore.

, :~3L7676e~

__ 2 As mentioned previously, in the overall assess-3 ment of ether a~ine collectors, a variety of factors must 4 be weighed. Particularly germane to the primary ether amines discussed herein is the element of cold weather 6 handling properties.
7 In Table IV, the ASTM pour point properties of 8 the linear Cg/Clo derivative is contrasted with that of 9 the Methyl-Branched Cg~Clo derivative. As will be noted the contrast is markedly in favor of the Methyl Branched 11 Cg/Clo material. The relatively high pour point figures 12 (o to -15 F) associated with the linear C8/Clo material 13 portend considerable handling problems with this material 14 at normal winter temp~ratures in the North American iron ore producing regions oE Michigan, Minnesota and Canada.
16T~3~E ~V

19LOW TEMPERATURE HANOLIHG PROP~RTIcS OF
20PRlMARY ThER AMINE F~OTATION COLLECTORS

No. of Dir~erent Pour Point 22 Co1~ector Samoles rested ASTM Test ~D-97-o6 ~ Mbthyl-~ranchet iso Cg~Clo oxypropyl Lower than -8P~
24 amine acetat~ (30~ neutralized) 4 (still liquid) 26 ~ Commercial~y-mar~eted 17near ~rozen solid 27 C8/CIo oxypropyl amine acetate (30S 0 to -15F
neutraliz8d) 3 29 Perhaps even more germane to the commercial suc-cess of this discovery is the cost of the potential ether 31 amines which can be used as the collector reagent. Pre-32 sented in Table V is a comparison of amine reagent costs 33 based on current raw material costs. Table V lists the 34 relative cost indicesfor those reagents tested on Ores 35 "A7' and "B".

` ' - ' ` ' ' ' ~67~5 T~B~E ~/

3 COMPARAT1'IE REAGcNT COST ~N8~C'S:
4 PQr~lARY ~THER AMI,~E F~O~A~ION COL~CTORS

6 Relatlve Cost 7 _ _ _ _ CollectDr ~ _ lndex ~ _ 8 ~ ,~ethtyl;jrad)hed iso Cg/Clo oxypropyl ami~e acetate (3a~l.CO
~ MRthyl-~ranched iso Cg oxypropyl amine acetate (30X 0 98 1 0 neutra1ized).
ethyl-branched fso Clo oxypropyl amine ac~tate (30Z 1 02 neutra1ized).
12 Ccmnercially-marke~ed linear Cg/Clo oxypropyl amine 1 3 acetate ~S; Clo/45 C8 by t; 30X neutralize~) 1.~1 14 ~inear Cg/Clo oxypropyl amine acetate (50/SO Cg/Clc wt.~,; 30~ neutralized).
1 5 Linear C8 oxypropyl amine acetate (30~ neutralizod). 1.32 1 6 9 ~inear Clo oxypropyl a~ine ac~tate (30~ neutral~ed). 1.37 17 2-ethyl hexyl oxypropyl amine acstate (30X ne~traliz~d). o.ga 1 8 ~ Primarlly llnear (sllghtly branched) Cg/Cl1 oxypropyl 1 25 1 9 amine acetato (30~ neutral12ed~.

21 ~N~ ased upon methyl-branched C3/Clo oxyproQyl amin~ acatat~ as l.CO.

2 3 I t i S seen that the methyl branched oxo alcohol 24 desivatives (iso-Cg, iso- Clo and iso Cg/Clo), as well as the 2-ethyl hexyl derivative enjoy a significant cost 26 advantage over the linear (or normal) derivatives. Of 27 the linear derivatives, the 50/50 linear Cg/Clo oxypropyl 28 amine acetate is the most economical, costing 21~ more 2 9 than the similar Cg/Clo methyl-branched derivative.
The following Table VI summarizes key evaluative 31 criteria for the nine flotation reagents considered in 32 these Examples. Rankings are given on a 1-9 basis, best 3 3 to worst, for each criterion:

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l Ta~e V
2 FLCtATlON ~AOENr_CRITE~ S~ARr 3 Flota~10r, ~er~or~nc~
4 01 ~llfle5 R~l t1ve L~ T~sr;~;uro Ptrs1stence TCtJ1 squ ~ r ~ 3~ss, S ~ PAr _~ SCOrC
6 ~ Y~cYl-br~ d 1so 1 yes a 7 . ~1~1C~C10 2 s s.s s ~, 17.5 o C~Clo ltnæ~r 7 ~. 5.5. 5 ~ 21.5 9 L1~r C8 g t â 5 no* 1~i5.
0 ~ ~thyl-brt-~clffd t5~ C8 8 l l.S 1 ~ no* Dis.
11 9 Pr11lu~ llno~r Cg/Cll 4 * 7 5 yes Dis.
12 ~ ~yl-br2nch~150Cl~ 3 * 4 1 yes Dis.
13 L~ Clo s * 9 5 yes Dis.
2-~rl~1 6 ++ L.5 l ~ Dis.

" Slgn1~1cs d1sqv 11f1c~t10n beau~- of ~ pesblo p-rto~n4n~.
t~t~ llat ~dL~.

18 *Dis. means disquali~ied.
l9 ~s will be noted from Table VI, the Methyl-Branched C8/Clo oxy-propyl monoamine acetate is easily the 21 optimum flotation reagent for the treatment of iron ores 22 comprised of ore subtypes "A" and "B". Six of the rea-23 gents tested disqualify because of inadequate flotation of 24 ore subtype "B" (inability to make 63% grade), or because of inadequate persistency.
26 Of the three remaining structures, the Methyl-27 Branched iso C8/Clo oxypropyl monoamine acetate is superi-2a or from the standpoints o~ flotation performance on both 29 ores and cost. Persistence was clearly adequate.
These findings illustrating the clear superiority 31 of the branched chain ether amines are especially interest-32 ing and surprisingly in light of published literature in-33 dicating that the linear -- or normal -- structures should 34 be superior.
For example, in the AIME book Flotation, Volume 36 1, 1976, a paper entitled "The Structural Effects of Amine ... ... , . . .. _ . _ ~L7~;~(65 1 Collectors on the Flotation of Quartz" (A. Bleier, A.D.
2 Goddard, and R. D. Culkarni of Unior Carbide) comprises 3 pages 117-147. On page 137, the following statement is made: "Collectors having a structure of RNH2 will be

5 more effective if the alkyl group R is linear, rather

6 than branched."

7 ~X~PLE 5: Performance o~ Various Concentrations oE the Isononyl Alcohol Derivatives g Commercially produced isononyl alcohol normally contains between 95 and 70~ isononyl alcohols, with the 11 remainder being comprised of isooctyl and/or isodecyl 12 alcohols. Accordingly, for this study, isononyl alcohol, 13 has been evaluated at a series of co~nercial purity levels:
14 9396, 84~, 74g6, and 50~6 isononyl alcohols. Converting each of these Cg solutions into ether monoamines, neutralizing 16 them to the 30~ ace-tate salt, and -testing them as flota-tion 17 collectors Eor Ore Subtype "A'', the following data, shown 18 in Table VII, were obtained:
19 TP~B ~ VII
ORE SUBTYPE "A": ~ Fe RECOVERY AT 65~ Fe GRADE
--- ~
Reaaent Dosaqe,Lbs~Lona_Ton of Ore 21 Reagent _ _ 0.15 0.20 0.25 0 _ 0 _ 0.40 - g3~ pure Cg deriva- 70.2 79.5 82.9 83.6 85.~ 87.6 23 tive 24 _ 84% pure Cg deriva- 67.9 78.6 82.1 83.1 86.2 R6.9 tive 26 _ 74% pure Cg deriva- 56.2 79.8 80.7 82.1 84.0 84.9 27 tive 28 _ 50% pure Cg deriva- * 76.2 82.0 83.0 84.2 8S.0 29 tive * Tests not conducted 32 From Table VII, it is obvious that all of the derivatives 33 containing Cg are extremely effective collectors for the 34 Ore Subtype "A". Most significant is that this family of collectors displays an extremely flat response curve, 36 vlz., the reagents appear to be ef~ective at a wide range 37 of dosages. Finally, one notes that, in general, the ~:~7~ S

1 higher the Cg purity, the better the iron recovery.
2 Utilizing the aforementioned partially neutralized 3 Cg derivatives as flotation collectors for Ore Subtype 4 "B", the followinq results, shown in Table VIII, were ob-tained:
6 Table ~
7 RE_SUE~TYPE "~ Fe_RECOVE}~Y AT 63% Fe GRP~DE

8 Reaqent Dosaqe, Lbs/~onc~ Ton of Ore ~ 0.20 0.2S 0.~0 0.3S 0.40 g _ _ .
- 93% Pure Cg derivative N/A 75.0 78.0 79.5 82.1 11 - 84% Pure Cg derivative 56.5 74.0 81.0 83.6 83.0 12 - 74% Pure Cg derivative 57.3 71.7 73.3 79.3 79.0 13 - 5~Q6 P~re Cg deri~ative * * ~ .*
14 * Tests not conducted Table VIII indicates that the Cg derivatives also appear 16 to be excellent flotation collectors for Ore Subtype "B".
17 As was the case for Ore Subtype "A", the Cg derivatives 18 apparently have a very flat response curve, especially 19 for concentrations at 0.25 lbs/ton and above. Also, in the case of Ore Subtype "B", the 84~ purity material 21 appears to be at least as good as, perhaps better than, the 22 93~ purity Cg derivative.
23 EXAMPLE 6: Performance of the Isononyl Alcohol Derivatives 24 versus the Linear and Branched Chain Ether Amine Collectors . ~ . .

~7~5 1 TABLE IX_ 2 ORE SUBTYPE "A~ Fe RECOVE~Y AT 65% Fe GRADE
3 Rea~ent Dosa~e,Lbs/Lonq Ton or Ore Reagent 0.20 0.25 0.30 0.35 0.40 -- Linear C8 derivative 45.5 73.2 76.6 79.0 79.2 -- Commercial Linear 59.6 7a .5 80.7 80.6 7 C8~C10 derivative 8 __ Linear Cg/Cll derivative 57.6 71.1 75.0 N/A
-- Branched C8/C~0 70.7 76.0 80.S 82.7 84.2 derivative Branched C10 derivative 58.8 77.7 82.~ 83.1 13 Methyl Branched Cg 14 -- 93~ pure C~ deriva- 79.5 82.9 83.6 85.9 87.6 -- 84% pure Cg deriva- 78~6 82.1 83.1 86.2 86.9 16 tlve 17 -- 74~ pure Cg deriva- 79.8 80.7 82.1 84.0 84.9 l8 tive -- 50~ pure C9 derivative 76.2 82.0 83.0 84.2 85.0 The comparative data of Table IX demonstrates the high 21 effectiveness of the methyl-branched Cg derivatives at all 22 concentrations down to 50% by volume. Not only do the Cg 23 derivatives yield higher recoveries at the mid and higher 24 range dosages, but they also offer relatively good re-coveries at the extremely low dosages of 0.20 and 0.15 lbs/
26 ton. The extremely flat response curve of the Cg deriva-27 tives across the entire dosage range is noteworthy.
28 The poor performance of the linear Cg/Cll deriva-29 tive is in contrast to that of the unique branched Cg derivatives at concentrations as low as 50~.

.

7~7~iS

1TABL~ X
2ORE SUBTYPE "B": % ~e RECOVERY AT 6 3 ~ Fe G~ADE
3Reaaent Dosaqe,Lbs/Lonq Ton of Ore ~ 0.25 0.30 0.35 0.40 6 ~~ Linear C~ derivative 68.1 77.1 79.2 80.1 7 -- Commercial linear 54.1 72.5 73 1 74.8 C8/C10 derivative

9 -- Branched CR derivative 71.3 70.6 76.4 80.5

10 __ Branched C8/C10 65.0 70.7 75.7 73.a

11 derivative

12 Methyl-branched Cg derivative - 93~ pure Cg derivative 75.0 78~0 79.5 82.1 14 -- 84~ pure Cg derivative 74.0 81.0 83.6 83.0 15 -- 74% pure Cg derivative 71.7 73.3 79.3 79.0 16 As Table X shows, the methyl-branched Cg 17 derivative at each of the concentrations tested, were 18 highly effective.
19 Although all tests indicate that Ore Subtype "B" is a more difficult ore to treat than Subtype "A" (re-21 covery values, even at a lower 63~ grade, are slightly 22 lower for each reagent), the methyl-branched Cg derivatives 23 continue to demonstrate: (a) the relatively flat response 24 curve property, and (b) the ability to treat well at low dosages.
26 Thus the methyl-branched Cg derivative is an 27 extraordinarily and surprisingly effective flotation col-28 lector for each of the two major ore subtypes which charac-29 terize a large commercial iron ore mining operation in the U.S. Great Lakes area.
31 EXAMPLE 7: Other Si~nificant Properties 32 Table XI is an evaluation of the methyl-branched 33 Cg derivative compared with the linear and branched deriva-34 tives insofar as these criteria are concerned:

'7~7~

~ ~ô
s~
~ ~ ~ (u ~ U U ~ h U
0 3 U~ ~ a~
Q) ~ . O Pq ::
~ ~U~ ~ O ~ O
~ ¢
'8 o.
U ~ C~l ~ ~rl O
S-l ~ ) I
~ rl r . ~ O 1 u ao~ ~ ~o ~,~ O
`:t `D ~ UC

o~l co 0~ ~
1~ , c~ o u C~ ~ U~

a) .~1 o ~ z ~0 ~ ~ ~ ~ ~r~
ul u~ ~ tn I al ~ ~u ~d U
~d a~ ~ ~ F~ u ~
. . ~,lo O
~J ~1 C`l ~ ~ O
r. ~ ~I
~1 ~
~a ~q ~ ,n 0 .D ~ ~ O

~CO O Q) h ~ ~
.1 l . . ~ ~ h ~1 ~:O O J O ~ eJ
h ~,1 P~
~ ~ e ~ ~
J .L~ - _ E~ ~ O
~1 ~ 3 C ,~
Il tOh Oh O O t~
O h O UO ~ 1~ $ o '~ "
~ t~l I I
¢ h 1 It has been found that the addition of one or more 2 moles of ethylene or propylene oxide to the methyl-3 branched isononyl alcohol yields promising flotation col-4 lectors when said ethoxylated or propoxylated alcohols are converted into ether amines and ether amine acetates via 6 the process described in Example l. These new structures 7 are shown in the following.
8 A. thoxylated _truc~ures ~ ~une ~-O-(C-C-O)z- C~C~CN
11 .
12 f ~

14 - > Amine Salt ~ ~C-C-O z- C~C ~ L

17 B. Propoxylated Structures _ ~ ~mine ~ z I ~ 3 22 r ~ H ~ Xl ~ ~mi ~ H H ~ l ~

28 Wherein R" i5 a methyl-branched isononyl radical as defined 29 above, X is an anion as defined above, and z is an integer of from l to l0, preferably 2 to 31 5.
32 As Table XII indicates, when evaluated as flotation 33 collectors upon the previously described Ore Subtype "A", 34 the ethoxylated and propoxylated methyl-branched isononyl derivatives yield promising results quite unlike similar 36 ethoxylated or propoxylated derivatives of methyl-branched 37 isooctyl or isodecyl alcohols.

67~i t TPBLE XII
REI~TIVE Fe RECt:)VERIES OF ETaOXYLATED AND PROPOXY~TED
3 ALCO~IOL_DERIVATIVES UPON ORE SUBTYPE_n~ ~ ~ 6 5~ CIIAD3 vs. Star~
Methyl~ 74% iso 2~yl derivative ~se standard 7 bra~ched Eth~lated (l m~le) 74% iso ncnyl ~ 1.5% rec~y 8 seres ~c~la~d (1 r~le) 74~ l (0-~96)~
der~Ltive ~
~ethyl- ~ B ~ ched ~ C8 derivati~e ~ standard 12 bra~ 9 E~x~ylated (l mole) C8 d~rivative=-Fail ~ **
~ies o P~ylated (1 mole) ~ d ~ vative Fail~re **
Methyl- ~ ~ched ~n ~0 ~2t;ve ~ standard iuxb~yl E~x~ylated (l mD~) ~0 desi~ative (1.5~) ~Kx~ry 16 P ~ lated (l nole) ~0 de~ e**
17 ~ -18 * 0.2~ is essentially equivalent to base standard recover~.
19 ** Failure is no~ed when raagen-t fails to elicit 65~ Fe Grade.
21 As can be noted above, either one mole of ethylene 22 oxide or one mole of propylene oxide is detrimental to the 23 performance of the isooctyl and isodecyl alcohol deriva-24 tives. Surprisingly, the methyl-branched C9 derivative appears to be improved by the addition of one mole of 26 ethylene oxide, and essentially unaffected by the addition 27 of one mole of propylene oxide.
28 Thus the isononyl ether propyl monoamine, derived 29 from isononyl alcohol, may have the general formulas R O (R )z C3H6 NH2 32 ~R"O (R''IO)z-C3H6-NH~ ~l 33 wherein R" is isononyl, R"' is ethyl or propyl, z is an 34 integer of from 0 to l0 and X represents an anion.
The invention in its broader aspect is not limited 36 to the specific details shown and described and departures 37 may be made from such details without departing from the 6'~

1 principles of the invention and without sacrificing i-ts 2 chief advantages.

Claims (14)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR PRIVILEGE
IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A froth flotation process for separating silica from iron ore, which comprises frothing said ore in an aqueous medium in the presence of 0.1 to 2 pounds per ton of said ore of a water dispersible, liquid mixture of aliphatic ether amines having the general formula:

where R- is a mixture of methyl branched aliphatic radicals having predominantly eight and ten carbon atoms, or of a water dispersible, liquid aliphatic ether amine having the general formula:
R"-O-(R'''-O)z-CH2-CH2-CH2-NH2 where R"- is an aliphatic methyl branched radical having 9 carbon atoms, R''' is ethyl or propyl and z is an integer of from 0 to 10.

2. The process according to claim 1 wherein said ether amines are partially or totally neutralized with a solubilizing anion.

3. The process according to claim 2 wherein said anion is acetate.

4. The process according to claim 1 wherein said iron ore is hematite.

5. The process according to claim 1 wherein said iron ore is martite.

6. The process according to claim 1 wherein said iron ore is geothite.

7. The process according to claim 1 wherein z is 1 and R''' is ethyl.

8. The process according to claim 1 wherein said mixture of aliphatic ether amines or salts thereof is an equal weight mixture of the ether amines or salts thereof wherein R- is methyl-branched C8 and C10 alkyl radicals.

9. The process according to claim 8 wherein the methyl branched C8 alkyl radicals are a mixture of dimethyl substituted hexyl alkyl radicals and the methyl branched C10 alkyl radicals are a mixture of trimethyl substituted heptyl alkyl radicals.

10. A froth flotation process according to claim 1 comprising the steps of frothing said ore in an aqueous medium in the presence of a mixture of methyl branched ether amines or the partially-neutralized salts thereof of the formula:

wherein R is a mixture of methyl branched aliphatic radicals having predominantly eight and ten carbon atoms and selecting the ratio of said mixture to give the best recovery for the entire range of mineral content of the feed ore.

11. The process according to claim 10 wherein said ore is martite with from 0 to 30 percent geothite and said mixture of methyl branched ether amine salts is an approximately equal weight mixture of salts wherein R- is dimethylhexyl, dimethyloctyl, or trimethyl heptyl.

12. A froth flotation process for separating silica from iron ore according to claim 2 comprising the step of adjusting the ratio of ether amine or partially-neutralized ether amine components in the dosage in response to the feed ore being processed, said components having the following general formulae:

or (R-O-CH2-CH2-CH2-NH3)+(X)-wherein R- is a mixture of methyl-branched aliphatic radicals having predominantly eight and ten carbon atoms, and X is an anion, whereby optimum iron recovery is realized.

13. The process according to claim 12 wherein said feed ore is primarily martite with only small amounts of geothite and the methyl branched ether amine salts are predominantly those derived from an oxo ten carbon alcohol.

14. The process according to claim 12 wherein said feed ore is martite with large amounts of geothite and the methyl branched ether amine salts are primarily those derived from an oxo eight carbon alcohol.