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(11) | EP 4 389 292 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | COLLECTOR COMPOSITION FOR RARE EARTH ORE BENEFICIATION |
| (57) The invention is related to a collector composition for the beneficiation of rare
earth element containing ores process using an improved collector to upgrade rare
earth element bearing minerals. The collector may be a combination of chemicals, comprising:
(1) at least one of any kind of fatty acid, derivative fatty acid, fatty acid ester
and combinations thereof and (2) hydroxamic acids or hydroxamates. The composition
may also include amines, preferably water-miscible alkanolamines, as well as sulfonates
containing compounds. The composition may also include sodium sulfonate, either natural
petroleum sulfonate or synthetic petroleum sulfonate. The collector may further comprise
frothers. With the invented collector, the separation efficiency from the unwanted
impurities can be significantly improved. The composition may also be devoid of an
effective amount of at least one of: phosphonic acid to function as a collector, a
rare earth depressant and combinations thereof. |
BACKGROUND OF THE INVENTION
Cross Reference.
Field of the Invention.
[0002] This invention relates generally to a collector composition for the beneficiation of rare earth element containing ores.
Description of the Related Art.
[0003] Rare earth elements (REEs), well known as "industrial vitamins", have specialized and vital applications in high-tech industrial, energy, defense, and medical sectors, given their unique chemical and physical properties.
[0004] REEs comprise the fifteen elements of the lanthanide series as well as Yttrium and Scandium, and may be found in over 250 different minerals. Separation techniques such as gravity, magnetic, electrostatic field and flotation have been used to separate REEs from gangue minerals. Flotation is attracting increasing attention as the easily-treated minerals have been depleted and the minerals in the current deposits often require to be heavily ground to achieve the liberations. Flotation is mainly used for two REE minerals: bastnaesite and monazite. However, the associated issues in flotation, mainly including weak selectivity of collectors, low-grade products, and insufficient recoveries of REEs, limit the development of the rare earth industry.
[0005] Bastnaesite is mainly composed of the cerium subgroups or lighter REEs. Two significant deposits of bastnaesite in the world are the Mountain Pass mineral deposit in California of USA and the Boyan Obo mineral deposit in Mongolia of China. In bastnaesite flotation, fatty acids are primary collectors. A previous patented collector is an emulsion consisting of secondary amine-modified sulphonated fatty acid, high rosin containing tall oil fatty acid, anionic petroleum sulfonate and high molecular weight primary amine. Hydroxamate is another important collector for the bastnaesite flotation. Mountain Pass is using a hydroxamate-based collector that can produce a final concentrate assaying 63% REO with 65-70% recovery. Monazite can be the primary rare earth oxide ("REO") mineral in heavy mineral sands. In some deposits, it is also in association with bastnasite. The monazite flotation can employe both fatty acid and hydroxamate collectors, due to the presence of similar surface cations found in bastnasite (Ce, La, etc.). However, it requires a depressant that is specific for the gangue minerals that include ilmenite, rutile, zircon, and quartz.
BRIEF DESCRIPTION
[0006] The below embodiments and other of the present disclosure will become apparent in light of the following disclosure.
[0007] In general, a first embodiment of the invention relates to a collector for beneficiating rare earth element containing ores comprising (a) at least one of a fatty acid, a fatty acid derivative, a fatty acid ester and combinations thereof and (b) at least one hydroxamic acid or hydroxamate.
[0008] Optionally, the first embodiment may be devoid of an effective amount of at least one of: phosphonic acid to function as a collector, a REE depressant and combinations thereof.
[0009] A second embodiment of the invention relates to a collector for beneficiating REE containing ores comprising at least two of the fatty acid, the fatty acid derivative, the fatty acid ester and combinations thereof and at least one hydroxamic acid or hydroxamate and optionally an amine, such as but not limited to a fatty (poly)amine, fatty amido (poly)amine, fatty imidazoline, fatty imidazo (poly)amine, fatty (poly) ester amine, fatty (poly) quaternized ammonium salt, an alkanolamine, preferably an alkanolamine, and/or sodium sulfonate. The composition may further comprise at least one frother. In one particular embodiment, the collector may comprise a majority of fatty acids or fatty acid derivatives such as sulfonated fatty acids, or their salts; approximately 0.5% to 20% by weight fatty acid esters; approximately 0.5% to 20% by weight hydroxamic acids or hydroxamates; optionally up to 5%; preferably up to 3% by weight amines; and optionally up to 15% sodium sulfonate. Another optional component may further comprise frothers.
[0010] The second embodiment may be devoid of an effective amount of at least one of: phosphonic acid to function as a collector, a REE depressant and combinations thereof.
[0011] The fatty acid may include 4-22 carbon atoms in the fatty chain and a terminal carboxyl group. Preferred fatty acids may include straight-chain fatty acids, branched chain fatty acids, cyclical molecules containing fatty acids, saturated, unsaturated, aromatic containing fatty acids, fatty acids containing at least one pendant hydroxyl group, preferably containing from 12 to 22 carbon atoms. Examples of sources of the fatty acid include vegetable or animal fats and oils. Tall oil fatty acid (TOFA) Soya fatty acid and canola fatty acid are preferred. Another example of a suitable fatty acid is a ricinoleic acid.
[0012] Fatty acid esters are esters that result from the esterification of fatty acids with alcohols. Biodiesels produced by the transesterification of vegetable fats and oils are suitable fatty acid esters. A non-limiting example of constituent fatty acids may be saturated or unsaturated fatty acids, branched chain fatty acids, cyclical containing fatty acids, and aromatic containing fatty acids with 6 to 22 carbon atoms. Examples of suitable alcohols for the esterification or transesterification are methanol, ethanol, butanol, and isopropanol, with methanol being preferred for making the fatty acids methyl esters.
[0013] The hydroxamic acids or hydroxamates have the formula (RC(=O)NH-O)nM where R is an alkyl, akenyl, aryl, alkylaryl or alkenylaryl group having 4 to 24 carbon atoms, preferably 6 to 24 carbon atoms, and M represents hydrogen, alkali metal, or alkaline earth metal with n being the valence of M.
[0014] In preferred embodiment R is an alkyl or akenyl group having 4 to 24 carbon atoms, preferably 6 to 24 carbon atoms, and M represents hydrogen, alkali metal, or alkaline earth metal with n being the valence of M.
[0015] It may be further preferred the hydroxamic acids or hydroxamates does not comprise either of benzohydroxamic acid and o-hydroxynaphthalene hydroximic acid.
[0017] The alkanolamines are a class of chemistry containing both hydroxyl and amino functional groups. The suitable alkanolamines are water-soluble or miscible with water, including but not limiting to aminoethylethanolamine, methanolamine, ethanolamine, N-methylethanolamine, dimethylethanolamine, ethylethanolamine, diethylethanolamine, propylethanolamine, dipropylethanolamine, butylethanolamine, dibutylethanolamine, diethanolamine, methyldiethanolamine, ethyldiethanolamine, propyldiethanolamine, butyldiethanolamine, triethanolamine, isobutanol-2-amine, valinol, alaninol, hydroxyethylpiperazine and combinations thereof. Preferred alkanolamines are aminoethylethanolamine, ethanolamine, methyldiethanolamine, diethanol amine, triethanolamine, hydroxyethylpiperazine and combinations thereof. The alkanolamines may be blended at any ratio.
[0018] The fatty (poly)amine, fatty amido (poly)amine, fatty imidazoline, fatty imidazo (poly)amine, fatty (poly) ester amine, fatty (poly) quaternized ammonium salt which may include 4-22 carbon atoms in the fatty chain. Preferred fatty chains may include straight-chains, branched chains, cycles containing chains, saturated, unsaturated, aromatic containing chains, chains with more than 8 carbon atoms containing at least one pendant hydroxyl group, preferably containing from 12 to 22 carbon atoms.
[0019] Sodium sulfonates include natural petroleum sulfonate and alkylbenzene derived synthetic petroleum sulfonate with molecular weight from 400 to 600.
[0020] The collector may further comprise frothers. Suitable frothers include but not limited to pine oil, methylisobutyl carbinol, alcohols, alkoxylated alcohols, alkoxylated methylisobutylcarbinol and polyglycols, alkoxylated meaning one to hundred, preferably one to sixty, more preferably one to forty repeating alkylene-oxy unit(s) wherein alkylene comprises from one to four carbon atoms in linear or branched chain.
[0022] A further embodiment may include a collector for beneficiating rare earth element containing ores comprising (a) at least two of the fatty acid, the fatty acid derivative the fatty acid ester and combinations thereof. Optionally, the embodiment may include the above optional or additional components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figures 1-4 illustrate the results of the Example regarding the collection of REE Ce (Figure 1), La (Figure 2), Nd (Figure 3) and Pr (Figure 4) relative to a control of a fatty acid collector.
DETAILED DESCRIPTION OF THE INVENTION
[0024] The description herein is merely illustrative of specific manners in which to make and use this invention and are not to be interpreted as limiting in scope. In addition, it is understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.
[0025] Unless otherwise defined herein, technical terms used in connection with the present disclosure shall have the meanings that are commonly understood by those of ordinary skill in the art. Further, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular.
[0026] All patents, published patent applications, and non-patent publications mentioned in the specification are indicative of the level of skill of those skilled in the art to which the present disclosure pertains. All patents, published patent applications, and non-patent publications referenced in any portion of this application are herein expressly incorporated by reference in their entirety to the same extent as if each individual patent or publication was specifically and individually indicated to be incorporated by reference.
[0027] All of the articles and/or methods disclosed herein can be made and executed without undue experimentation in light of the present disclosure. While the articles and methods of the present disclosure have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations can be applied to the articles and/or methods and in the steps or in the sequence of steps of the method(s) described herein without departing from the concept, spirit and scope of the present disclosure. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the present disclosure.
[0028] While the collector compositions have been described with a certain degree of particularity, it is to be noted that many modifications may be made in the details of the components without departing from the spirit and scope of this disclosure. It is understood that the compositions are not limited to the embodiments set forth herein for purposes of exemplification.
[0029] The term "at least one" refers to one as well as any quantity more than one, including but not limited to, 1, 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 100, etc. The term "at least one" can extend up to 100 or 1000 or more depending on the term to which it is attached.
[0030] All percentages, parts, proportions, and ratios as used herein are by weight of the total composition, unless otherwise specified. All such weights as they pertain to listed ingredients are based on the active level and therefore do not include solvents or by-products that can be included in commercially available materials, unless otherwise specified.
[0031] All references to singular characteristics or limitations of the present invention shall include the corresponding plural characteristics or limitations, and vice-versa, unless otherwise specified or clearly implied to the contrary by the context in which the reference is made.
[0032] Numerical ranges as used herein are intended to include every number and subset of numbers contained within that range, whether specifically disclosed or not. Further, these numerical ranges should be construed as providing support for a claim directed to any number or subset of numbers in that range.
[0033] As used herein, the words "comprising" (and any form of comprising, such as "comprise" and "comprises"), "having" (and any form of having, such as "have" and "has"), "including" (and any form of including, such as "includes" and "include") or "containing" (and any form of containing, such as "contains" and "contain") are inclusive or open-ended and do not exclude additional, unrecited elements or method steps. The terms "or combinations thereof' and "and/or combinations thereof' as used herein refer to all permutations and combinations of the listed items preceding the term. For example, "A, B, C, or combinations thereof' is intended to include at least one of: A, B, C, AB, AC, BC, or ABC and, if order is important in a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB. Continuing with this example, expressly included are combinations that contain repeats of one or more items or terms, such as BB, AAA, AAB, BBC, AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan will understand that typically there is no limit on the number of items or terms in any combination, unless otherwise apparent from the context.
[0034] For purposes of the following detailed description, other than in any operating examples, or where otherwise indicated, numbers that express, for example, quantities of ingredients used in the specification and claims are to be understood as being modified in all instances by the term "about". The numerical parameters set forth in the specification and attached claims are approximations that can vary depending upon the desired properties to be obtained in carrying out the invention.
[0035] The term "or combinations thereof, "and combinations thereof, and "combinations thereof' as used herein refers to all permutations and combinations of the listed items preceding the term.
[0036] In general, the invention relates to a novel collector for use in a flotation process for the beneficiation of rare earth element ("REE") containing ores. The collector may be a combination of chemicals, including (1) at least one of: one or more fatty acids, one or more fatty acids derivatives, one or more fatty acid esters; and (2) one or more hydroxamic acids or hydroxamates. An example of the fatty acid derivative may include fatty acid salts. An optional additional component may be one or more amines, e.g., fatty (poly)amine, fatty amido (poly)amine, fatty imidazoline, fatty imidazo (poly)amine, fatty (poly) ester amine, fatty (poly) quaternized ammonium salt, alkanolamine, sodium sulfonate and combinations thereof. If so, desired the composition may include one or more frothers. A further optional component may include polyols such as diols and/or triols. One particular example of such polyols includes polypropylene glycol ("PPG"). These components may be mixed together as one product or may be added separately but preferably at the same time. The separate addition may be either simultaneous or sequential, preferably at the conditioning step prior to flotation. The collector may be emulsified by adding water and suitable emulsifiers before applying to froth flotation.
[0037] The composition may be devoid of an effective amount of phosphonic acid to function as a collector. Phosphonic acid may also be referred to as phosphorous acid. Devoid of an effective amount herein includes also less than 1% by wt, as well as trace amounts and less than trace amounts.
[0038] Phosphonic acid as used herein does not include phosphoric acid. However, an optional embodiment includes the composition further devoid of an effective amount of phosphoric acid to function as a collector. With respect to phosphoric acid, devoid of an effective amount includes less than 1% by wt, as well as trace amounts and less than trace amounts.
[0039] The composition may also be devoid of an effective amount of a REE depressant. The devoid of an effective amount also includes less than 1% by wt, as well as trace amounts and less than trace amounts.
[0040] As stated, the composition may include fatty acids, fatty acid derivatives, esters of fatty acids and combinations thereof. Preferable fatty acid chains may include straight chain fatty acids and their derivatives, branched fatty acid chains and their derivatives, cycle containing fatty acid chains and their derivatives, saturated, unsaturated, aromatic containing fatty acid chains and their derivatives containing from 12 to 22 carbon atoms. The fatty acid chains are not limited to a linear compound; it may be nonlinear. Typical sources for the fatty acids may be vegetable or animal fats and oils. Tall oil fatty acid and canola fatty acid are preferred. The fatty acids may be present in salt form. Preferred amounts of fatty acid/ fatty acid salts included in the composition may range from about 51% to 99% by weight, about 55% to 98% by weight, about 60% to 97% by weight, about 65% to 96% by weight, about 70% to 95% by weight and about 80 to 90% by weight.
[0041] Regarding the fatty acid esters, sample constituent fatty acids may be either saturated or unsaturated; preferably they contain 6 to 22 carbon atoms. The hydrocarbon chain of the fatty acids may be linear, branched, cyclic, or aromatic. Suitable alcohols for the esterification or transesterification for making fatty acid esters are methanol, ethanol, butanol, and isopropanol, with methanol being preferred. A concentration of the fatty acid ester in the composition may range from about 1% to 20% by weight, from about 2% to 10% by weight and from more than 2% by weight to less than 10% by weight.
[0042] The composition may include hydroxamic acids, hydroxamates and combinations thereof. Examples of non-polar hydrocarbon chains of the hydroxamic acids or hydroxamates are straight or branched C6 to C22 alkyl, alkenyl, aryl, alkylaryl or alkenylaryl groups. A concentration of the hydroxamic acids or hydroxamates in the composition may range from about 0.5% to 20% by weight, from about 1% to 10% by weight and from more than about 1.5% by weight to less than 10% by weight.
[0043] More preferred embodiments of the hydroxamic acids, hydroxamates and combinations thereof include C8-C18 alkyl or alkenyl hydroxamic acids or hydroxamates. Preferred concentrations of such hydroxamic acids or hydroxamates may comprise less than about 10%, preferably less than about 5%, and even more preferred less than about 4%.
[0044] In one specific embodiment, the hydroxamic acids or hydroxamates comprises an ammonium hydroximic acid. Preferred concentrations of the ammonium hydroximic acid may comprise less than about 10%, more preferred less than about 5% and even more preferred less than about 4%.
[0045] The composition may inlcude sodium sulfonates, natural petroleum sulfonate or alkylbenzene derived synthetic petroleum sulfonate. A concentration of the sodium sulfonate in the composition may range from 0 to 15% by weight, the afore concentrations are also applicable to the petroleum sulfonate compounds listed above.
[0046] One example of suitable fatty acid chains, their derivatives and fatty acid ester chains may include 6 to 14 carbon atoms. Preferably compounds may have 8, 10, 12 carbon atoms or any combination of compounds having such amount of carbon atoms.
[0047] Another example of suitable fatty acid chains, their derivatives and fatty acid ester chains may include 8 to 22 carbon atoms. Particular preferred fatty acid chains, their derivatives and fatty acid ester chains include C16 to C18 carbon chains. Specific examples may include oleic acid, linoleic acid, their derivates and esters thereof.
[0048] The alkanolamines contain both hydroxyl and amino functional groups. Preferably, the alkanolamines may be water soluble or miscible with water with a preference of aminoethylethanolamine, ethanolamine, diethanol amine, methyldiethanolamine, triethanolamine, hydroxyethylpiperazine and combinations thereof. Preferably concentrations of alkanolamines range from more than trace amounts to less than about 5% by weight, preferably less no more than about 3% by weight, even more preferably no more than about 2.5% and even further preferred no more than about 2% by weight.
[0049] The fatty (poly)amine, fatty amido (poly)amine, fatty imidazoline, fatty imidazo (poly)amine, fatty (poly) ester amine, fatty (poly) quaternized ammonium salt may include 4-22 carbon atoms in the fatty chain. Preferred fatty chains may include straight-chains, branched chains, cycles containing chains, saturated, unsaturated, aromatic containing chains, chains with more than 8 carbon atoms containing at least one pendant hydroxyl group, preferably containing from 12 to 22 carbon atoms. Preferably concentrations of fatty (poly)amine, fatty amido (poly)amine, fatty imidazoline, fatty imidazo (poly)amine, fatty (poly) ester amine, fatty (poly) quaternized ammonium salt range from more than trace amounts to less than about 5% by weight, preferably less no more than about 3% by weight, even more preferably no more than about 2.5% and even further preferred no more than about 2% by weight.
[0050] Frothers can be any commonly used frothers like pine oil, methylisobutyl carbinol, alcohols, alkoxylated alcohols, alkoxylated methylisobutyl carbinol, polyglycols to improve the froth properties such as stability and density, ranging from 0.5 to 5% by weight.
[0051] If so desired, the composition may be devoid of an effective amount of silicon to boost separation efficiency.
[0052] If so desired, the composition may be devoid of any more than trace amounts of any of alkyne compounds, alkylbenzene compounds and combinations thereof.
[0053] If so desired, the composition may be devoid of an effective amount of a sulfonated compound that functions as a collector.
[0054] If so desired, the composition may be devoid of an effective amount of a separate rare earth element depressant.
[0055] An advantage of the disclosed collector is that it may be used to routinely concentrate rare earth elements (rare earth oxides or "REO") (such as Neodymium (Nd), Yttrium (Y), Lanthanum (La), Scandium (Sc), Dysprosium (Dy), Terbium (Tb), Europium (Eu), Praseodymium (Pr), Gadolinium (Gd), Cerium (Ce), Samarium (Sm), Ytterbium (Yb), Holmium (Ho), Lutetium (Lu), Thulium (Tm), Erbium (Er) and Promethium (Pm)) from mined ores having at least about 1% REO into a concentration having at least about 4.5% of REO by a single flotation, preferably greater than about 5.0% and have a recovery of at least about 70% of the REO, preferably greater than about 70%, even more preferably at least about 75%.
[0056] A further advantage may include that the disclosed collector can improve REE recovery by more than about 5% over known collectors, preferably about 10% or more.
ASPECTS
[0057] A first aspect of the invention includes a composition (a) at least one of a fatty acid and/or fatty acid derivative and (b) at least one hydroxamic acid or hydroxamate.
[0058] A second aspect of the invention includes a composition comprising: (a) at least one of a fatty acid, a fatty acid salt, a fatty acid ester and combinations thereof and (b) at least one hydroxamic acid or hydroxamate.
[0059] In a third aspect the composition of the first or second aspect further comprises at least one amine, sodium sulfonate or a combination of both. One example of a suitable amine is an alkanolamine.
[0061] In a fifth aspect, applicable to anyone of aspects 1-4 wherein a concentration of the fatty acid, fatty acid derivative or the fatty acid salt comprises a majority of the composition by weight.
[0062] In a sixth aspect, the composition of anyone of aspects 1-5 comprises up to about 20% by weight of the fatty acid ester and/or the hydroxamic acid or the hydroxamates.
[0063] In a seventh aspect, applicable to the composition of anyone of the preceding aspects 1-6 wherein the constituent fatty acid of the fatty acid esters comprises saturated or unsaturated compound with 6 to 22 carbon atoms.
[0064] In an eighth aspect, the composition of anyone of aspects 1-7 wherein the hydroxamic acid has the formula:
(RC(=O)NH-O)nM
wherein R is an alkyl, alkenyl, aryl, alkylaryl or alkenylaryl group having 4 to 24 carbon atoms, preferably 6 to 24 carbon atoms, and M represents a hydrogen, alkali metal, or alkaline earth metal with n being charge of valence of M.
[0065] In a nineth aspect, the composition of anyone of aspects 1-8 wherein the amine comprises both hydroxyl and amino functional groups and is miscible in water or water soluble.
[0066] In a tenth aspect, the composition of anyone of aspects 1-9 wherein the amine comprises at least one selected from the group of aminoethylethanolamine, methanolamine, ethanolamine, diethanolamine, methydiethanolamine, triethanolamine, and aminoethylpiperazine, hydroxyethylpiperazine and combinations thereof.
[0067] An eleventh aspect includes a beneficiation process for separating impurities from REE containing ore. The process includes pulping the ore to produce an ore slurry; reagentizing the ore slurry to produce a reagentized slurry by adding: a collector comprising: (a) at least one fatty acid, fatty acid derivative and combinations thereof, (b) at least one fatty acid ester (c) at least one hydroxamic acid or hydroxamate, (d) at least one amine and optionally a sodium sulfonate. The process may also include separating at least some of the impurities from the REE and collecting the REE in the form of a concentrate.
[0068] Regarding a twelfth aspect, the reagentizing of the eleventh aspect does not include introducing a separate REE depressant.
[0069] In a thirteenth aspect, applicable to either of aspect 11 or 12, the reagentizing the ore slurry further comprises adding a pH modifier.
[0070] In a fourteenth aspect, applicable to anyone of aspects 10-13, the reagentizing further comprises separately adding at least one of (a) the fatty acid or fatty acid derivative (b) the fatty acid ester (c) the hydroxamic acid or hydroxamate or (d) the amine.
[0071] In a fifteenth aspect, applicable to anyone of aspects 10-14 the process further comprises combining at least two of (a) the fatty acid or fatty acid derivative, (b) the fatty acid ester (c) the hydroxamic acid or hydroxamate or (d) the alkanolamine prior to being added to the ore slurry.
[0072] Aspect sixteen is a flotation method for removing gangue from REE containing ores. The method includes producing an ore slurry comprising REE containing ore and a collector. The collector may comprise (a) at least one fatty acid or fatty acid derivative, (b) at least one fatty acid ester (c) at least one hydroxamic acid or hydroxamate and (d) at least one of an alkanolamine or a sodium sulfonate. The method also includes subjecting the ore slurry to flotation.
[0074] In aspect eighteen, applicable to either one of aspects 16 or 17 wherein the subjecting the ore slurry to flotation produces an underflow and an overflow, the method further comprising: separating one of the overflows or the underflow as the gangue; and collecting the other of the underflow or the overflow as REE concentrate.
[0075] In a nineteenth aspect, the composition of any one of aspects 1-15, the composition is used for the beneficiation of a rare earth.
[0076] A twentieth aspect a composition comprising (a) at least one fatty acid and/or fatty acid derivative (b) at least one hydroxamic acid or hydroxamate and (c) an amine.
[0077] In a twenty-first aspect applicable to any one of the preceding aspects, the collector composition may be devoid of an effective amount of at least one of: a phosphonic acid functioning as collector, a REE depressant and combinations thereof.
[0078] In a twenty-second aspect applicable to any one of the preceding aspects, the hydroxamic acid or hydroxamate does not comprise an aryl group.
Examples
[0079] The present invention is further illustrated by the following examples. In order that those skilled in the field may better understand how the present invention can be practiced, the following examples are given by way of illustration only and not necessarily by way of limitation. The examples described below share the same procedure for the direct flotation of REE containing ores. All the tests were carried out at room temperature. The REE ores were scrubbed at alkaline pH at 50% solids and then deslimed using 635-mesh sieve. The deslimed slurry was conditioned at 40% solid in 4-liter Denver float cell at 1200 RPM with collector dosage for 5 minutes. After conditioning, the slurry was subject to rougher flotation. The concentrate slurry from the rougher flotation was subject to a few cleaner flotation stages in 2-liter Denver float cell. The cleaner flotation steps were repeated until a desired level of REE was collected in the concentrate. Before each cleaner flotation, the concentrate slurry from the preceding step was conditioned for 2 minutes at 1000 RPM.
Example I
[0080] REE feed containing mainly monazite was from Australia. Flotation feed was ground to pass P80 = 90 micron. Along with collector addition, 800 g/t sodium silicate was applied in the conditioning at 35% solids for 5 minutes with NaOH controlling pH 10.5. Temperature control was in place. After conditioning, the rougher flotation was conducted with kinetic flotation tests using the site standard procedure. Lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), etc. were measured for collector performance. Higher concentration and higher recovery indicated better performance. Schematic lab flotation flowsheet shown in Figure 1 further illustrates the above.
[0081] Compositions of two collectors, a fatty acid collector ("Control") and the invented collector Samples C and D are shown in Table 1. The flotation performances of two reagents are presented in Table II. It can be found that the invented collector Samples C and D significantly increased the REE recovery.
Table I
| Components | Control | Sample D |
| Fatty acids | 100% | 92.00% |
| Fatty acid ester | 5.50% | |
| Alkyl Hydroxamic Acid | 1.50% | |
| Alkanolamine | 0.20% | |
| 2-ethylhexanol | 0.80% |
1. A rare earth element collector from rare earth element containing ores comprising:
(a) at least one of a fatty acid, a fatty acid derivative, a fatty acid ester and
combinations thereof, and (b) at least one hydroxamic acid or hydroxamate.
2. The rare earth element collector of claim 1 further comprising devoid of an effective
amount of at least one of a phosphonic acid to function as a collector, a rare earth
depressant and combinations thereof.
3. The collector of either of claim 1 or claim 2 further comprising at least one amine.
4. The collector of anyone of the preceding claims further comprising a frother.
5. The collector of anyone of the preceding claims wherein a concentration of the fatty
acid or the fatty acid derivative comprises no more than about 99% by weight and at
least about 48% by weight of the collector.
6. The collector of anyone of claims 2-4 wherein the collector comprises up to about
20% by weight of the fatty acid ester and/or the hydroxamic acid or the hydroxamates.
7. The collector of anyone of claims 1-6 wherein the fatty acid comprises more than one
of the fatty acids, the fatty acid derivatives and the combinations thereof.
8. The collector of anyone of claims 2-7 wherein a constituent fatty acid of the fatty
acid esters comprises saturated or unsaturated compound with 6 to 22 carbon atoms.
9. The collector of anyone of claims 1-8 wherein the hydroxamic acid has the formula:
(RC(=O)NH-O)nM
where R is an alkyl, alkenyl, aryl, alkenylaryl or alkylaryl group having 4 to 24 carbon atoms, preferably 6 to 24 carbon atoms, and M represents a hydrogen, alkali metal, or alkaline earth metal with n being the valence of M.
(RC(=O)NH-O)nM
where R is an alkyl, alkenyl, aryl, alkenylaryl or alkylaryl group having 4 to 24 carbon atoms, preferably 6 to 24 carbon atoms, and M represents a hydrogen, alkali metal, or alkaline earth metal with n being the valence of M.
10. The collector of anyone of claims 3-9 wherein the amine comprises both hydroxyl and
amino functional groups.
11. The collector of anyone of claims 3-10 wherein the amine comprises at least one selected
from the group of a fatty (poly)amine, fatty amido (poly)amine, fatty imidazoline,
fatty imidazo (poly)amine, fatty (poly) ester amine, fatty (poly) quaternized ammonium
salt, aminoethylethanolamine, methanolamine, ethanolamine, N-methylethanolamine, dimethylethanolamine,
ethylethanolamine, diethylethanolamine, propylethanolamine, dipropylethanolamine,
butylethanolamine, dibutylethanolamine, diethanolamine, methyldiethanolamine, ethyldiethanolamine,
propyldiethanolamine, butyldiethanolamine, triethanolamine, isobutanol-2-amine, valinol,
alaninol, hydroxyethylpiperazine and combinations thereof.
12. The collector of anyone of claims 4-11 wherein the frother comprises at least one
selected from the group of pine oil, methylisobutyl carbinol, alcohols, alkoxylated
alcohols, alkoxylated methylisobutyl carbinol, polyglycols and combinations thereof.
13. The collector of anyone of claims 1-12 wherein the fatty acid or salt comprises a
majority of the collector by weight.
14. The collector of anyone of claims 2-13 wherein the fatty acid ester comprises about
0.5% to 20% by weight of the collector.
15. The collector of anyone of claims 1-14 wherein the hydroxamic acid comprises about
0.5% to 20% by weight of the collector.
16. The collector of anyone of claims 1-15 wherein the amine comprises an alkanolamine
and up to about 5%, preferably up to 3%, by weight of the collector.
17. The collector of anyone of claims 1-16 wherein the collector comprises an emulsion.
18. The collector of anyone of claims 1-17, wherein
the fatty acid comprises a majority of the collector by weight;
approximately about 0.5% to 10% by weight the fatty acid esters;
approximately about 0.5% to 10% by weight of the hydroxamic acids or hydroxamates; and
approximately about 0.1% to 3% by weight of the alkanolamine.
19. The collector of anyone of claim 1-18 comprising up to about 15 wt. % of a sulfonate
containing compound.
20. The collector of claim 19 wherein the sulfonate compound comprises at least one selected
from sodium sulfonates, natural petroleum sulfonate, alkylbenzene derived synthetic
petroleum sulfonate and combinations thereof.
21. The collector of any one of the preceding claims wherein the hydroxamic acid or hydroxamate
devoid of an aryl group.
22. The collector of any one of the preceding claims wherein the hydroxamic acid or hydroxamate
comprises at least one of an alkyl hydroxamic acid or hydroxamate compound, an alkenyl
hydroxamic acid or hydroxamate and combinations thereof.