EP2313200B1 - Inorganic particles comprising an organic coating that can be hydrophilically/hydrophobically temperature controlled - Google Patents

Abstract

The invention relates to a method for separating at least one first substance from a mixture containing said at least one first substance and at least one second substance. Said method consists of the following steps: (A) the mixture containing the at least one first substance and at least one second substance is brought into contact with at least one selective hydrophobing agent in the presence of a suspension agent such that an adduct is formed form at least one hydrophobing agent and the at least one first substance, and not from the at least one second substance; (B) the adduct from step (A) is brought into contact with at least one magnetic particle which is functionalised on the surface with at least one polymer compound having a transition temperature LCST (Lower Critical Solution Temperature), at a temperature at which the polymer compound has a hydrophobic character, such that the adduct from step (A) and the at least one functionalised magnetic particle agglomerates; (C) another suspending agent is optionally added to the mixture obtained in step (B); (D) the agglomerate present in the suspension in steps (B) or (C) is separated by applying a magnetic field; (E) the agglomerate separated in step (D) is divided by controlling a temperature at which the polymer compound has a hydrophilic character, in order to obtain at least one first substance.

Description

The present invention relates to a process for the separation of at least one first substance from a mixture containing said first material and at least one second substance, wherein the mixture to be separated is first contacted with at least one selective hydrophobizing agent so that the at least one hydrophobizing agent and forming at least one first material an adduct, then contacting said adduct with at least one magnetic particle functionalized at the surface with at least one polymeric compound having a LCST (Lower Critical Solution Temperature) at a temperature at which the polymeric compound hydrophobic character, so that the adduct and the at least one functionalized magnetic particle agglomerate, this agglomerate is separated by applying a magnetic field, and the agglomerate is finally cleaved by a temperature is set at de the polymeric compound has a hydrophilic character.

"Hydrophobic" in the context of the present invention means that the surface of a corresponding "hydrophobic substance" or a "hydrophobized substance" has a contact angle of> 90 ° with water against air. "Hydrophilic" in the context of the present invention means that the surface of a corresponding "hydrophilic substance" has a contact angle of <90 ° with water against air.

With the method according to the invention, mixtures of substances, for example ores, can be separated by treating the substances to be separated, for example sulphidic compounds, with a selective hydrophobizing agent in order to hydrophobize them on the surface. These hydrophobized substances can then be separated by means of magnetic particles functionalized on the surface with a polymeric compound having an LCST. These polymeric compounds have hydrophobic character above the LCST and hydrophilic character below the LCST, or vice versa. If these polymeric compounds or magnetic particles which are functionalized on the surface with these polymeric compounds are heated, a change in the hydrophilic character of the polymeric compound to hydrophobic character takes place in the LCST or, conversely, a change from a hydrophobic character to a hydrophilic character. Therefore, bringing together the hydrophobized material and the switchably functionalized magnetic particles at a temperature at which the polymeric compound has a hydrophobic character takes place the formation of an agglomerate of functionalized magnetic particles and hydrophobized material. This agglomerate can then be separated by applying a magnetic field. Subsequent cleavage of the agglomerate can take place by bringing it to a temperature at which the polymeric compound has a hydrophilic character so that hydrophobic interactions between functionalized magnetic particle and hydrophobized substance are no longer possible.

In particular, the present invention relates to a method for enriching ores in the presence of gait.

Methods for separating ores from mixtures containing them with the aid of magnetic particles are already known from the prior art.

WO 02/0066168 A1 relates to a process for the separation of ores from mixtures containing them, in which suspensions or slurries of these mixtures are treated with particles which are magnetic and / or buoyant in aqueous solutions. After addition of the magnetic and / or buoyant particles, a magnetic field is applied so that the agglomerates are separated from the mixture. However, the degree of attachment of the magnetic particles to the ore and the strength of the bond is not sufficient to perform the process with sufficiently high yield and effectiveness.

US 4,657,666 discloses a method for enrichment of ores where the ginger ore is reacted with magnetic particles to form agglomerates due to the hydrophobic interactions. The magnetic particles are hydrophobized by treatment with hydrophobic compounds on the surface, so that a connection to the value ore takes place. The agglomerates are then separated from the mixture by a magnetic field. The cited document also discloses that the ores are treated with a surface activating solution of 1% sodium ethylxanthogenate before the magnetic particle is added. Separation of ore and magnetic particles occurs in this process by destroying the surface-activating substance which has been applied to the ore in the form of the surface-activating solution. A disadvantage of this method is that, if necessary, a surface-activating substance is added, the degradation products of which remain in the ore and may possibly interfere with further process steps.

US 4,834,898 discloses a method of separating non-magnetic materials by contacting them with magnetic reagents having two layers are enveloped by surface-active substances. The attachment of the thus modified magnetic reagents to the non-magnetic materials is based on an interaction of the coating of the magnetic particles with the non-magnetic materials. In this method, it is disadvantageous that the magnetic particles must be elaborately provided with two layers of surface-active substances in order to achieve a coupling.

SR Gray, D. Landberg, NB Gray, Extractive Metallurgy Conference, Perth, 2-4 October 1991, pages 223-226 discloses a method of recovering small gold particles by contacting the particles with magnetite. Before contacting, the gold particles are treated with potassium amylxanthogenate. A method for separating the gold particles from at least one hydrophilic substance is not disclosed in this document.

Li et al., International Journal of Pharmacology (2006), 2 (5), 513-519 , disclose thermosensitive polymers that are homogeneously in solution below the Lower Critical Solution Temperature (LCST), while when this temperature is exceeded, a heterogeneous biphasic mixture forms. Furthermore, applications of these targeted drug delivery polymers are disclosed.

Crespy et al., Polymer International (2007), 56 (12), 1461-1468 also disclose polymers which show hydrophilic or hydrophobic behavior depending on the ambient temperature. Furthermore, the use of these polymers in textiles and for the targeted release of pharmaceutically active substances is disclosed.

EP 1 316 599 A discloses a process for the preparation of magnetic particles having on its surface polymers having an UCST (Upper Critical Solution Temperature). These functionalized particles can be used for purification, detection or concentration of nucleic acids or enzymes or as separation reagents. As examples of substances which can be separated by the magnetic particles, there are mentioned avidin, avidinylated enzymes or biotinylated enzymes.

DE 195 16 323 A1 discloses a process for preparing magnetizable dispersions and their use. According to page 4, from line 28 these are iron-containing particles which are functionalized on the surface with various compounds. These compounds are attached, for example via a carboxylic acid functionality to the iron-containing particles. Subsequently, the compounds have 2 to 6 units of ethylene oxide. The other end of the polymeric compound has either a hydroxy or a carboxylic acid group.

None of the cited documents discloses that polymers which have an LCST can be used for substance separation.

The object of the present invention is to provide a method by which at least one first substance can be efficiently separated from mixtures comprising these at least one first substance and at least one second substance. Furthermore, it is an object of the present invention to provide a method in which it is possible to be able to split the agglomerate of magnetic particles and the first material to be separated in the meantime easily and as completely as possible. Furthermore, the bond between the first material to be separated and magnetic particles should be sufficiently stable to ensure a high yield of first material upon separation.

1. (A) Inkontaktbringen der Mischung enthaltend den wenigstens einen ersten Stoff und wenigstens einen zweiten Stoff mit wenigstens einem selektiven Hydrophobierungsmittel in Gegenwart eines Suspendiermittels, so dass sich aus dem wenigstens einen Hydrophobierungsmittels und dem wenigstens einen ersten Stoff, nicht aber mit dem wenigstens einen zweiten Stoff, ein Addukt bildet,
2. (B) Inkontaktbringen des Adduktes aus Schritt (A) mit wenigstens einem Magnetpartikel, der an der Oberfläche mit wenigstens einer polymeren Verbindung funktionalisiert ist, die eine Übergangstemperatur LCST (Lower Critical Solution Temperature) aufweist, bei einer Temperatur, bei der die polymere Verbindung hydrophoben Charakter aufweist, so dass das Addukt aus Schritt (A) und der wenigstens eine funktionalisierte Magnetpartikel agglomerieren,
3. (C) gegebenenfalls Zugabe von weiterem Suspendiermittel zu der in Schritt (B) erhaltenen Mischung,
4. (D) Abtrennen des in der Suspension aus Schritt (B) oder (C) vorliegenden Agglomerates durch Anlegen einen magnetischen Feldes,
5. (E) Spalten des in Schritt (D) abgetrennten Agglomerates durch Einstellen einer Temperatur, bei der die polymere Verbindung hydrophilen Charakter aufweist, um den wenigstens einen ersten Stoff zu erhalten.

The objects are achieved by the inventive method for separating at least one first substance selected from the group consisting of sulfidic ores, oxidic and / or carbonate ores and mixtures thereof, or precious metals and their compounds from a mixture containing this at least a first fabric and at least one second fabric, comprising the following steps:

1. (A) contacting the mixture containing the at least one first substance and at least one second substance with at least one selective hydrophobizing agent in the presence of a suspending agent such that the at least one hydrophobizing agent and the at least one first substance, but not with the at least one second substance , forms an adduct,
2. (B) contacting the adduct of step (A) with at least one magnetic particle functionalized on the surface with at least one polymeric compound having a lower critical solution temperature (LCST) at a temperature at which the polymeric compound is hydrophobic Character, such that the adduct of step (A) and the at least one functionalized magnetic particle agglomerate,
3. (C) optionally adding further suspending agent to the mixture obtained in step (B),
4. (D) separating the agglomerate present in the suspension from step (B) or (C) by applying a magnetic field,
5. (E) cleaving the agglomerate separated in step (D) by adjusting a temperature at which the polymeric compound has hydrophilic character to obtain the at least one first substance.

The at least one first substance and the at least one second substance can be separated from one another by the method according to the invention, since according to the invention at least one between hydrophobic and hydrophilic switchable functionalized magnetic particles is added under conditions to the mixture, among which at least one first hydrophobized material and the at least one functionalized magnetic particle forms an agglomerate which can be separated by applying a magnetic field.

The method according to the invention generally serves to separate at least one first substance from a mixture comprising this at least one first substance and at least one second substance. In addition to these components, the mixture may also contain other substances.

The at least one first material to be separated off is preferably a metal compound selected from the group consisting of sulfide ores, oxidic and / or carbonate ores, for example azurite [Cu ₃ (CO ₃ ) ₂ (OH) ₂ ], or malachite [Cu ₂ [(OH ) ₂ | CO ₃ ]]). Furthermore, the at least one material to be separated off can be selected from the group of the noble metals and their compounds, for example Au, Pt, Pd, Rh, etc., preferably in a solid state.

Examples of sulfidic ores which can be used according to the invention are selected from the group of sulfide non-ferrous metals, for example copper ores such as covellite CuS, chalcopyrite CuFeS ₂ , bornite Cu ₅ FeS ₄ , chalcocite Cu ₂ S or mixtures thereof, molybdenum ores such as molybdenum (IV ) sulfide molybdenum MoS ₂ , iron sulfides such as FeS / FeS ₂ , nickel ores such as NiS, lead ores such as PbS, zinc ores such as ZnS or mixtures thereof:

The at least one second substance is preferably selected from the group consisting of oxidic metal and semimetal compounds, hydroxidic metal and semimetal compounds and mixtures thereof, for example silicon dioxide SiO ₂ , silicates, aluminosilicates, for example feldspars (Ba, Ca, Na, K, NH ₄ ) (Al, B, Si) ₄ O ₈ , for example albite Na (Si ₃ Al) O ₈ or anorthite (CaAl ₂ Si ₂ O ₈ ), olivine (Mg, Fe) ₂ SiO ₄ , mica, for example muscovite KAl ₂ [ (OH, F) ₂ AlSi ₃ O ₁₀ ], garnets (X ₃ Y ₂ (SiO ₄ ) ₃ with X = Mg, Ca, Fe (II), Mn (II) and Y = Al, Fe (III), Cr (III), Ti (III), V (III)), FeO (OH), FeCO _3, and other related minerals and mixtures thereof. Furthermore, oxidic compounds of metals and semimetals, for example borates or other salts of metals and semimetals, for example phosphates, sulfates or oxides / hydroxides / carbonates and further salts, may be present in the ore mixtures to be treated according to the invention, for example azurite [Cu ₃ (CO ₃ ) ₂ (OH) ₂ ], malachite [Cu ₂ [(OH) ₂ (Co ₃ )]]. Barite (BaSO ₄ ), monazite ((Ce, La, Nd) [PO ₄ ]).

In the process according to the invention untreated ore mixtures are preferably used, which are obtained from mine deposits.

In a preferred embodiment of the method according to the invention, the mixture containing at least one first substance and at least one second substance in step (A) is in the form of particles having a size of 100 nm to 100 μm, see for example US 5,051,199 , In a preferred embodiment, this particle size becomes obtained by grinding. Suitable methods and devices are known to the person skilled in the art, for example wet milling in a ball mill.

In a preferred embodiment of the method according to the invention, the mixture containing at least one first substance and at least one second substance before or during step (A) to particles having a size of 100 nm to 500 .mu.m, preferably 100 nm to 100 microns milled.

Preferably usable ore mixtures have the highest possible content of sulfidic minerals. A typically used ore mixture, which can be separated by the method according to the invention, has the following composition: about 30 wt .-% SiO ₂ , about 10 wt .-% Na (Si ₃ Al) O ₈ , about 3 wt. -% Cu ₂ S, about 1 wt .-% MoS ₂ , balance chromium, iron, titanium and magnesium oxides.

The individual steps of the method according to the invention are described in detail below:

Step (A):

Step (A) of the method according to the invention comprises contacting the mixture containing the at least one first substance and at least one second substance with at least one selective hydrophobizing agent in a suitable suspending agent, so that the at least one hydrophobizing agent and the at least one first substance but not forms with the at least one second substance, an adduct.

The first step of the process according to the invention serves to hydrophobize the at least one first substance on the surface so that in the following step (B) it agglomerates with the at least one functionalized magnetic particle.

Methods for hydrophobizing the surface of the at least one first material are known to those skilled in the art.

In the context of the present invention, "hydrophobing agent" means a substance which is capable of hydrophobizing the surface of the at least one first substance in the presence of the other particles which are not to be separated, ie of modifying the surface of the hydrophobized one at least one first substance has a contact angle of> 90 ° with water against air.

"Selective" in the context of the present invention means that the distribution coefficient of the hydrophobing agent between the surface of the at least one first substance and the surface of the at least one second substance, in general> 1, preferably> 100, particularly preferably> 10000, d. h., That the hydrophobizing agent preferably on the surface of the at least one first substance, and not on the surface of the at least one second substance, attached.

A

ausgewählt ist aus linearem oder verzweigtem C₃-C₃₀-Alkyl, C₃-C₃₀-Heteroalkyl, gegebenenfalls substituiertes C₆-C₃₀-Aryl , gegebenenfalls substituiertes C₆-C₃₀-Heteroalkyl, C₆-C₃₀-Aralkyl,

Z

eine Gruppe ist, mit der die Verbindung der allgemeinen Formel (I) an den wenigstens einen ersten Stoff anbindet und

x

1, 2 oder 3 ist.

In the process according to the invention, preference is given to using at least one hydrophobizing agent of the general formula (I)

A- (Z) _x (I)

used, which binds to the at least one first material, wherein

A

is selected from linear or branched C ₃ -C ₃₀ -alkyl, C ₃ -C ₃₀ -Heteroalkyl, optionally substituted C ₆ -C ₃₀ -aryl, optionally substituted C ₆ -C ₃₀ -Heteroalkyl, C ₆ -C ₃₀ -aralkyl,

Z

is a group with which the compound of the general formula (I) binds to the at least one first substance and

x

1, 2 or 3.

In a particularly preferred embodiment, A is a linear or branched C ₆ -C ₁₆ -alkyl, for example 2-propyl-heptyl. Optionally present heteroatoms according to the invention are selected from N, O, P, S and halogens such as F, Cl, Br and I.

In a further particularly preferred embodiment Z is selected from the group consisting of anionic groups - (X) _n -PO 3 ^2- , - (X) _n -PO ₂ S ^2- , - (X) _n -POS ₂ ^2- , - (X) _n -PS ₃ ^2-, Dithiophosphinat [- (X) _{n] 2} P ₂ ^-, - [(X) _{n] 2} POS ^- dithiophosphate [- (X) _{n] 2} PO ₂ ^-, - (X ) _n -CO ₂ ^- , - (X) _n -CS ₂ ^- , - (X) _n -COS ^- , - (X) _n -C (S) NHOH, - (X) _n -S ^- with X selected from the group consisting of O, S, NH, CH ₂ and n = 0, 1 or 2, with optionally cations selected from the group consisting of hydrogen, NR ₄ ⁺ where R is independently hydrogen and / or C ₁ -C ₈ - Alkyl, alkali or alkaline earth metals. The anions mentioned and the corresponding cations form neutral charged compounds of the general formula (I) according to the invention. In the case of Dithiophosphinat [- (X) _{n] 2} P ₂ ^-, - [(X) _{n] 2} POS ^- or dithiophosphate [- (X) _{n] 2} PO ₂ ^- are present at these functional groups attached two radicals A, the, in the context of the above meanings may be the same or different, preferably equal and selected from C ₆ -C ₃₀ , more preferably C ₆ -C ₁₆ alkyl.

In a very particularly preferred embodiment of the method according to the invention Z is [- (X) _{n] 2} P ₂ ^-, - (X) _n -CS ₂ ^-, - [(X) _{n] 2} PO ₂ ^-, or - (X) _n -S ^- where X is O and n is 0 or 1 and a cation selected from hydrogen, sodium or potassium.

For noble metals, for example Au, Pd, Rh etc., particularly preferred hydrophobizing agents are mono-, di- and trithiols or 8-hydroxyquinolines, for example described in US Pat EP 1200408 B1 ,

For metal oxides, for example FeO (OH), Fe ₃ O ₄ , ZnO etc., carbonates, for example azurite [Cu (CO ₃ ) ₂ (OH) ₂ ], malachite [Cu ₂ [(OH) ₂ CO ₃ ]] particularly preferred hydrophobizing agents C ₆ -C ₁₆ -alkylphosphonic acids, for example octylphosphonic acid (OPS), mono- and dialkyl esters of phosphoric acid with a C ₆ -C ₂₀ -alkyl radical, hydroxamates, and long-chain carboxylic acids (fatty acids).

worin R unabhängig von einander Wasserstoff oder C₆-C₃₀-Alkyl und X unabhängig von einander S oder O bedeuten, wobei ein bis drei der vorliegenden X S und die verbleibenden O bedeuten,For metal sulfides, for example Cu ₂ S, MoS ₂ , etc., particularly preferred water repellents are mono-, di- and trithiols, xanthates, dithiophosphinates or mono-, di- or tri-C ₆ -C ₃₀ -alkyl esters of thiophosphoric acids of the general formula (VII)

in which R independently of one another denote hydrogen or C ₆ -C ₃₀ -alkyl and X independently of one another denote S or O, where one to three of the XS present and the remaining O mean

mit den oben genannten Bedeutungen für A.Very particularly preferred surface-active substances are 1-octanethiol, potassium octylxanthate, octylphosphonic acid, phosphoric acid monooctyl ester or a compound of the general formula (IV)

with the meanings given above for A.

The contacting in step (A) of the process according to the invention can be carried out by all methods known to the person skilled in the art. For example, the mixture to be treated, the at least one hydrophobing agent and the suspending agent in the appropriate amounts are added together and mixed. The mixing can be done for example by wet milling. Suitable mixing apparatuses are known to the person skilled in the art, for example mills, such as ball mill.

The suspending agent is generally added in step (A) in an amount such that the suspension obtained has a solids content of from 0.1 to 80% by weight, preferably from 20 to 40% by weight.

In general, all suspending agents known to those skilled in the art can be used in the process according to the invention, i. H. Suspending agents in which the mixture of step (A) is not completely soluble. In a preferred embodiment, the suspending agent is an aqueous mixture, i. H. a mixture containing at least 80% by weight, preferably at least 95% by weight, of water. In a particularly preferred embodiment, the suspending agent in step (A) is water.

The suspending agent may contain, in addition to water, other components, for example selected from the group consisting of water-soluble organic compounds such as alcohols having 1 to 4 carbon atoms, ketones such as acetone and mixtures thereof, soluble salts such as NaCl, KCl, MgCl ₂ , CaCl ₂ , Na ₂ CO ₃ , K ₂ CO ₃ , MgCO ₃ , inorganic acids and bases such as NaOH, KOH, Ca (OH) ₂ , HCl, H ₂ SO ₄ , HNO ₃ , organic acids and bases such as formic acid or acetic acid, etc.

Step (A) of the process according to the invention is generally carried out at a temperature of 1 to 80 ° C, preferably at 40 to 60 ° C.

The at least one water repellent is generally used in an amount sufficient to achieve the desired effect. In a preferred embodiment, the at least one hydrophobizing agent is in an amount from 0.01 to 5 wt .-%, in each case based on the present in the mixture at least one first material.

After step (A) according to the invention is a mixture in suspension before containing an adduct of at least a first material and at least one hydrophobizing agent, and at least one second material.

Step (B):

Step (B) of the process of the invention comprises contacting the adduct of step (A) with at least one magnetic particle functionalized on the surface with at least one polymeric compound having a lower critical solution temperature (LCST) at a temperature, wherein the polymeric compound has hydrophobic character such that the adduct of step (A) and the at least one functionalized magnetic particle agglomerate.

As magnetic particles, it is generally possible to use all magnetic particles known to the person skilled in the art which satisfy the requirements of the process according to the invention, for example suspensibility in the optionally used suspending agent and ability to be functionalized with the at least one polymeric compound.

Furthermore, the magnetic particle should have a sufficiently high saturation magnetizability, for example 25-300 emu / g, and a low remanence, so that the adduct can be separated from the suspension in a sufficient amount in step (D) of the process according to the invention.

M

ausgewählt aus Co, Ni, Mn, Zn und Mischungen davon und

x

≤ 1,

hexagonalen Ferriten, beispielsweise Barium- oder Strontiumferrit MFe₁₂O₁₉ mit M = Ca, Sr, Ba, und Mischungen davon.In a preferred embodiment, the at least one magnetic particle is selected from the group consisting of magnetic metals, for example iron, cobalt, nickel and mixtures thereof, ferromagnetic alloys of magnetic metals, magnetic iron oxides, for example magnetite, maghemite, cubic ferrites of the general formula (II)

M ²⁺ _x Fe ²⁺ _1-x Fe ³⁺ ₂ O ₄ (II)

With

M

selected from Co, Ni, Mn, Zn and mixtures thereof and

x

≤ 1,

hexagonal ferrites, for example barium or strontium ferrite MFe ₁₂ O ₁₉ with M = Ca, Sr, Ba, and mixtures thereof.

In a particularly preferred embodiment of the present application, the at least one magnetic particle is magnetite Fe ₃ O ₄ or cobalt ferrite Co ²⁺ _x Fe ²⁺ _1-x Fe ³⁺ ₂ O ₄ with x ≦ 1, for example CO _{2 .25} Fe _{2, 75} o ₄ .

The size of the magnetic particles used according to the invention is preferably from 10 nm to 1 .mu.m.

The at least one magnetic particle is functionalized on the surface with at least one polymeric compound. The polymeric compounds used according to the invention are characterized in that they have a transition temperature LCST (Lower Critical Solution Temperature). Below this LCST, the polymeric compound has a hydrophilic character since the polymer chain has a hydration shell, for example due to addition of water molecules. Above the LCST, the polymeric compound has a hydrophobic character, since the polymer chain is no longer surrounded by a hydrate shell, for example. Depending on the polymeric compound, the reverse case is also possible, namely that the polymeric compound below the LCST has a hydrophobic character and has a hydrophilic character above the LCST. When such a polymeric compound is heated from below the LCST to a temperature above the LCST, the polymeric compound switches from hydrophilic to hydrophobic in the LCST, or vice versa. Thus, the polymers which can be used according to the invention, depending on the temperature, have a hydrophilic or hydrophobic character.

The change of the polymeric compound from hydrophobic to hydrophilic or vice versa corresponds to a phase transition, which takes place in a closed system generally in a narrow temperature range, for example 0.5 ° C. For example, in an open system, the phase transition may extend over a broader range of, for example, 15 ° C, by changing the concentration of the present components, for example, polymers and / or impurities, varying the pH and / or pressure. The temperature range at which the transition occurs generally increases with increasing chain length. When changing the molecular properties of hydrophilic to hydrophobic, generally remain some water molecules attached to the polymer, which are released suksezziv. This process is generally completely reversible as long as the polymeric compound is not chemically modified, for example by increasing the pH.

The properties described for the polymeric compounds which can be used according to the invention are essentially correspondingly also present in the case of the particles modified with these polymeric compounds, in particular magnetic particles.

In a preferred embodiment of the process according to the invention, the polymeric compound above the LCST is hydrophobic and hydrophilic below the LCST.

According to the invention, it is possible to use all polymeric compounds which have an LCST, ie. H. which have hydrophilic or hydrophobic character at different temperatures. In the context of the present invention, "polymer" means a, preferably organic, compound having a molecular weight of at least 500 g / mol, preferably 500 to 10000 g / mol, particularly preferably 1000 to 7000 g / mol.

In a preferred embodiment of the process according to the invention, the at least one polymeric compound is selected from the group consisting of polyvinyl ethers, for example polyvinylmethylethers, poly-N-alkylacrylamides, for example poly-NC ₁ -C ₆ -alkylacrylamides, in particular polyvinylethers. N-isopropylacrylamide, or N-alkyl-acrylamide-acrylamide copolymers, poly-N-vinyl-caprolactams, copolymers based on alkylene oxides, for example copolymers of ethylene oxide, propylene oxide and / or butylene oxide, preferably polymeric compounds obtainable by alkoxylation of C ₁ C ₁₂ alcohols having 1 to 130 units of ethylene oxide, propylene oxide and / or butylene oxide, and mixtures thereof. Suitable polymeric compounds and processes for their preparation are, for example, in Li et al., International Journal of Pharmacology (2006), 2 (5), 513-519 , and Crespy et al., Polymer International (2007), 56 (12), 1461-1468 , called. These polymeric compounds have hydrophobic character below the LCST and hydrophobic character above the LCST.

und Mischungen davon, besonders bevorzugt ausgewählt aus der Gruppe bestehend aus Thiolgruppe -SH, Carbonsäuregruppe -CO₂H, gegebenenfalls zumindest teilweise veresterte Phosphonsäuregruppe -PO₃R'₂ mit R' gleich Wasserstoff oder C₁-C₆-Alkyl (Va), gegebenenfalls zumindest teilweise veresterte Phosphorsäuregruppe -O-PO₃R"₂ mit R" gleich Wasserstoff oder C₁-C₆-Alkyl (Vb), Hydroxamatgruppe (Vc). Die Xanthogenatgruppe (Vd) ist bevorzugt für die Kupplung an sulfidische Verbindungen geeignet.The abovementioned polymeric compounds which have an LCST are bound by functional groups to the corresponding magnetic particles. These functional groups can be present in said polymeric compounds per se, or the functional groups can be introduced into the polymeric compounds by methods known to those skilled in the art, ie the polymeric compounds are functionalized. Suitable functional groups are those which ensure a sufficiently strong bond between magnetic particle and polymeric compound, for example selected from the group consisting of thiol group -SH, carboxylic acid group -CO ₂ H, optionally at least partially esterified phosphonic acid group -PO ₃ R ' ₂ with R' same Hydrogen or C ₁ -C ₆ -alkyl (Va), optionally at least partially esterified phosphoric acid group -O-PO ₃ R " ₂ with R "equal to hydrogen or C ₁ -C ₆ -alkyl (Vb), hydroxamate group (Vc), xanthate group (Vd)

and mixtures thereof, more preferably selected from the group consisting of thiol group -SH, carboxylic acid group -CO ₂ H, optionally at least partially esterified phosphonic acid group -PO ₃ R ' ₂ with R' equal to hydrogen or C ₁ -C ₆ -alkyl (Va), optionally at least partially esterified phosphoric acid group -O-PO ₃ R " ₂ with R" equal to hydrogen or C ₁ -C ₆ alkyl (Vb), hydroxamate (Vc). The xanthate group (Vd) is preferably suitable for coupling to sulfidic compounds.

F

funktionelle Gruppe, die selektiv an den wenigstens einen Magnetpartikel bindet,

B

Alkylrest mit 1 bis 6 Kohlenstoffatomen,

EO

Ethylenoxid,

PO

Propylenoxid,

BuO

Butylenoxid,

x

ganze oder gebrochene Zahl von 0 bis 130, bevorzugt 0 bis 40

y

ganze oder gebrochene Zahl von 0 bis 130, bevorzugt 1 bis 35 und

z

ganze oder gebrochene Zahl von 0 bis 130, bevorzugt 0 bis 40,

wobei 1 ≤ x+y+z ≤ 130, bevorzugt 10 ≤ x+y+z ≤ 130 gilt, bedeuten.In a preferred embodiment, the at least one polymeric compound is at least one functionalized copolymer of ethylene oxide, propylene oxide and / or butylene oxide, more preferably a compound of general formula (III)

F - [(EO) _x - (PO) _y - (BuO) _z ] -B (III)

wherein

F

functional group that selectively binds to the at least one magnetic particle,

B

Alkyl radical having 1 to 6 carbon atoms,

EO

ethylene oxide,

PO

propylene oxide,

BuO

butylene oxide,

x

integer or fractional number from 0 to 130, preferably 0 to 40

y

whole or fractional number from 0 to 130, preferably 1 to 35 and

z

whole or fractional number from 0 to 130, preferably 0 to 40,

where 1 ≦ x + y + z ≦ 130, preferably 10 ≦ x + y + z ≦ 130.

In the compound of the general formula (III), F represents a functional group which selectively binds to the at least one magnetic particle. The choice of this functional group depends on the at least one magnetic particle to which the functional group is to bind. It is preferable to form a dissociation-stable bond between the at least one magnetic particle and the at least one polymeric compound of general formula (III).

und Mischungen davon, besonders bevorzugt eine gegebenenfalls zumindest teilweise veresterte Phosphonsäuregruppe (Va) oder eine gegebenenfalls zumindest teilweise veresterte Phosphorsäuregruppe (Vb).In a preferred embodiment, F is selected from the group consisting of carboxylic acid group -CO ₂ H, optionally at least partially esterified phosphonic acid group -PO ₃ R ' ₂ with R' equal to hydrogen or C ₁ -C ₆ alkyl (Va), optionally at least partially esterified Phosphoric acid group -O-PO ₃ R " ₂ with R" equal to hydrogen or C ₁ -C ₆ -alkyl (Vb), hydroxamate group (Vc), xanthogenate group (Vd)

and mixtures thereof, particularly preferably an optionally at least partially esterified phosphonic acid group (Va) or an optionally at least partially esterified phosphoric acid group (Vb).

The binding of the functional groups Va to Vd to the polymer preferably takes place via lone-pair electrons.

In the general formula (III), B represents an alkyl group having 1 to 6 carbon atoms, for example, methyl, ethyl, propyl, butyl, for example, n-butyl, pentyl, hexyl.

The polymeric compounds of the general formula (III) have an LCST which is generally in each case dependent on the amount of the individual alkylene oxides, ie. H. Ethylene oxide, propylene oxide and / or butylene oxide, is dependent in the polymer. For example, a polymeric compound composed solely of propylene oxide has an LCST of <-10 ° C. A polymeric compound which is composed exclusively of ethylene oxide, for example, has an LCST of> 120 ° C. By selecting the type and amount of the alkylene oxides, it is thus possible to adjust an LCST of the polymeric compound which is suitable for the process according to the invention.

In a preferred embodiment, the LCST of the polymeric compound used in the process according to the invention is -10 to 100 ° C, more preferably 5 to 45 ° C, most preferably 20 to 40 ° C. In general, the LCST of a polymeric compound is in a temperature range of about 5 to 15 ° C. The width of this area is generally dependent on uniformity, i. H. the monodispersity, the polymeric compound used. The higher the monodispersity, the narrower the range of the LCST.

Processes for the preparation of polymeric compounds of the general formula (III) are known to the person skilled in the art.

The functionalization of the at least one magnetic particle with the at least one polymeric compound can be carried out by all methods known to the person skilled in the art. In a preferred embodiment, the at least one magnetic particle is functionalized with the at least one polymeric compound by first preparing the magnetic particle itself by known methods. Then, this magnetic particle is modified by contacting a solution of the functionalized polymeric compound, in particular compounds of the general formula (III), in water or in an organic solvent, for example low molecular weight alcohols or ketones, and the product obtained is used to remove excess polymeric compound washed with an appropriate solvent.

The contacting of the adduct from step (A) with at least one functionalized magnetic particle in step (B) can be carried out by all methods known to the person skilled in the art. In a preferred embodiment, the at least one functionalized magnetic particle is added to the mixture of step (A). In a preferred embodiment, step (B) is carried out in a mill, more preferably in the same mill in which step (A) has been carried out. Preferably, the heat generated when milling the components in step (B) is used to achieve the temperature necessary for step (A) in the mixture, preferably in the case where the polymeric compound is hydrophobic above its LCST.

Step (B) of the process according to the invention is carried out at a temperature at which the polymeric compound used has a hydrophobic character so that the switchably functionalized magnetic particle and the hydrophobized at least one first material agglomerate. Depending on the polymeric compound, this temperature may be above or below the LCST, preferably the temperature is above the LCST.

Preferably, step (B) is conducted at a temperature greater than the LCST of the polymeric compound and less than the boiling point of the suspending agent used. More preferably, step (B) is carried out at a temperature which is 1 to 20 ° C above the LCST. Thus, in a preferred embodiment, step (B) is carried out at a temperature of 6 to 65 ° C, more preferably 21 to 60 ° C.

In the event that the polymeric compound below the LCST hydrophobic character, step (B) of the inventive method is carried out at a temperature which is above the melting temperature of the suspending agent used and below the LCST of the polymeric compound. Preferably, in this case, step (B) is carried out at a temperature which is 1 to 20 ° C below the LCST. For this case, step (B) is thus preferably carried out at a temperature of from -15 to 44.degree. C., more preferably from 0 to 39.degree.

Step (B) of the process according to the invention is preferably carried out until a sufficient amount of agglomerate of at least one hydrophobized first material and switchable functionalized magnetic particles is formed, for example in a proportion of 80 to 100%, preferably completely (100%).

After step (B) of the process according to the invention, agglomerates of magnetic particles functionalized on the surface with at least one polymeric compound and at least one hydrophobicized first substance are present in addition to at least one second substance and optionally further substances in a suspending agent.

Step (C)

The optional step (C) of the process of the invention comprises (C) the addition of further suspending agent to the mixture obtained in step (B).

Step (C) is preferably carried out when, in step (A), a suspension has been provided whose solids content is too high for the following steps (D) and (E), such that, for example, the mobility of those formed in step (B) Agglomerates in the suspension is not sufficient.

In step (C) of the process according to the invention, all suspending agents which have already been mentioned with regard to step (A) are suitable as suspending agents. In a preferred embodiment, in step (C), an aqueous mixture, i. H. a mixture containing at least 80% by weight, preferably at least 95% by weight, of water. The aqueous mixture may additionally contain the components referred to in step (A). In a particularly preferred embodiment, water is added in step (C) of the process according to the invention.

Step (C) of the process according to the invention is generally carried out at a temperature at which the agglomerate formed in step (B) from at least one hydrophobized substance and the functionalized magnetic particle is not cleaved.

Thus, step (C) is carried out at a temperature greater than the LCST of the polymeric compound and less than the boiling point of the suspending agent used is. More preferably, step (C) is carried out at a temperature which is 1 to 20 ° C above the LCST. Thus, in a preferred embodiment, step (C) is carried out at a temperature of 6 to 65 ° C, more preferably 21 to 60 ° C.

In the event that the polymeric compound below the LCST hydrophobic character, step (C) of the inventive method is carried out at a temperature which is above the melting temperature of the suspending agent used and below the LCST of the polymeric compound. Preferably, in this case, step (C) is carried out at a temperature which is 1 to 20 ° C below the LCST. For this case, step (C) is thus preferably carried out at a temperature of -15 to 44 ° C, more preferably 0 to 39 ° C.

In general, the amount of suspending agent according to the invention can be chosen so that in step (C) a suspension is obtained which is easy to stir and / or convey. In a preferred embodiment, a suitable suspending agent is added so that a solids content of the resulting suspension of 0.1 to 80 wt .-%, particularly preferably 0.1 to 40 wt .-% results.

Step (D)

Step (D) of the process according to the invention comprises separating the agglomerate present in the suspension from step (B) or (C) by applying a magnetic field.

Step (D) may be carried out in a preferred embodiment by introducing a permanent magnet into the reactor in which the suspension from step (B) or (C) is located. In a preferred embodiment is located between the permanent magnet and the mixture to be treated, a partition wall of non-magnetic material, such as the wall of the reactor. In a further preferred embodiment of the method according to the invention, an electrically switchable magnet is used in step (D) which is magnetic only when an electric current flows. Suitable devices are known in the art.

Step (D) of the process according to the invention is generally carried out at a temperature at which the agglomerate formed in step (B) from at least one hydrophobized substance and the functionalized magnetic particle is not cleaved.

Thus, step (D) is preferably carried out at a temperature which is greater than the LCST of the polymeric compound and less than the boiling point of the suspending agent used. Particularly preferably, step (D) is carried out at a temperature which is 1 to 20 ° C above the LCST. Thus, in a preferred embodiment, step (D) is carried out at a temperature of 6 to 65 ° C, more preferably 21 to 60 ° C.

In the event that the polymeric compound below the LCST hydrophobic character, step (D) of the inventive method is carried out at a temperature which is above the melting temperature of the suspending agent used and below the LCST of the polymeric compound. Preferably, in this case, step (D) is carried out at a temperature which is 1 to 20 ° C below the LCST. For this case, step (D) is thus preferably carried out at a temperature of -15 to 44 ° C, particularly preferably 0 to 39 ° C.

The steps (B), (C) and (D) can be carried out at the same temperature, it is according to the invention also possible that the steps at different temperatures, in the specified ranges, are performed.

During step (D), the mixture is mixed, preferably permanently, with a suitable device.

In step (D), the components remaining in the suspension after treatment with a magnet may optionally be separated by any means known to those skilled in the art, for example by draining the portions of the suspension which are not captured by the magnet from the bottom valve of step by step (D) used reactor or pumping the not captured by the at least one magnet portions of the suspension.

After step (D) of the process according to the invention, the agglomerate formed in step (B) of the process according to the invention consists of at least one functionalized magnetic particle and the at least one hydrophobized first substance on the magnet or on a wall which is located between magnet and adduct. For an electrically switchable magnet, the adduct may be removed from the magnet by shutting off the electrical current so that there is no more magnetic field gradient. If there is a wall between the magnet and the suspension, then the adduct can be removed by methods known to those skilled in the art.

Steps)

Step (E) of the process of the present invention comprises cleaving the agglomerate separated in step (D) by adjusting a temperature at which the polymeric compound has a hydrophilic character to obtain the at least one first substance.

Depending on whether a polymeric compound having a hydrophilic character below or above the LCST is used in the process according to the invention, the temperature in step (E) of the process according to the invention is set.

For the preferred case that the polymeric compound has hydrophilic character below the LCST, step (E) of the process of the invention is carried out at a temperature which is above the melting temperature of the suspending agent employed and below the LCST of the polymeric compound. Preferably, in this case, step (E) is carried out at a temperature which is 1 to 20 ° C below the LCST. For this case, step (E) is thus preferably carried out at a temperature of -15 to 44 ° C, particularly preferably 0 to 39 ° C.

In the event that the polymeric compound above the LCST has hydrophilic character, step (E) is carried out at a temperature which is greater than the LCST of the polymeric compound and less than the boiling point of the suspending agent used. Particularly preferably, step (E) is carried out in this case at a temperature which is 1 to 20 ° C above the LCST. Thus, in a preferred embodiment, step (D) is carried out at a temperature of 6 to 65 ° C, more preferably 21 to 60 ° C.

At the temperature prevailing in step (E) of the process of the invention, the polymeric compound has hydrophilic character, i. there can be no hydrophobic interactions between the polymeric compound on the surface of the at least one magnetic particle and the hydrophobized first material, so that the agglomerates are cleaved.

Step (E) of the process according to the invention is carried out until the agglomerates present are cleaved as completely as possible, for example to a proportion of 70 to 99%, preferably 80 to 98%.

After cleavage of the agglomerate, the at least one functionalized magnetic particle and the at least one hydrophobized first substance are suspended Form before. These two substances can be separated from one another and from the suspending agent by all methods known to those skilled in the art.

The at least one magnetic particle is preferably separated from the suspension containing this at least one magnetic particle and the at least one first material by a permanent or switchable magnet. Details of this separation are analogous to step (D) of the method according to the invention. Preferably, after this separation, the at least one first substance is present in suspended form, while the at least one magnetic particle adheres to the magnet.

Preferably, the first material to be separated is separated from the suspending agent by distilling off the suspending agent or filtration. The first substance thus obtained can be purified by further methods known to the person skilled in the art. The suspending agent may, optionally after purification, be recycled back to the process of the invention. Likewise, in a preferred embodiment, the at least one magnetic particle is recycled in step (A) of the process according to the invention.

P

Partikel, enthaltend wenigstens ein Metall oder Halbmetall,

F

funktionelle Gruppe,

B

Alkylrest mit 1 bis 6 Kohlenstoffatomen,

EO

Ethylenoxid,

PO

Propylenoxid,

BuO

Butylenoxid,

x

ganze oder gebrochene Zahl von 0 bis 130, bevorzugt 0 bis 40,

y

ganze oder gebrochene Zahl von 0 bis 130, bevorzugt 1 bis 35,

z

ganze oder gebrochene Zahl von 0 bis 130, bevorzugt 0 bis 40, mit 1 ≤ x+y+z ≤ 130, bevorzugt 10 ≤ x+y+z ≤ 130, und

q

ganze Zahl von 1 bis 1 * 10¹⁵

bedeuten.The present invention also relates to functionalized particles of the general formula (VI)

P- {F - [(EO) _x - (PO) _y - (BuO) _z ] -B} _q (VI),

wherein

P

Particles containing at least one metal or semimetal,

F

functional group,

B

Alkyl radical having 1 to 6 carbon atoms,

EO

ethylene oxide,

PO

propylene oxide,

BuO

butylene oxide,

x

whole or fractional number from 0 to 130, preferably 0 to 40,

y

whole or fractional number from 0 to 130, preferably 1 to 35,

z

integer or fractional number from 0 to 130, preferably 0 to 40, with 1 ≦ x + y + z ≦ 130, preferably 10 ≦ x + y + z ≦ 130, and

q

integer from 1 to 1 * 10 ¹⁵

mean.

In the compound of general formula (VI), P generally denotes a particle containing at least one metal or semimetal, preferably in oxidic or sulfidic form.

Examples of particles which contain at least one metal in oxidic form are, for example, selected from the group consisting of secondary or main group metal oxides, for example CuO, ZnO, Cr ₂ O ₃ , Fe ₂ O ₃ , TiO ₂ , SiO ₂ , CeO ₂ , Titanates, for example BaTiO ₃ , SrTiO ₃ and mixtures thereof.

Examples of particles containing at least one metal in sulfidic form are, for example, selected from the group consisting of subgroup metal sulfides, for example CuS, Zn _1-x Mn _x S with 0 ≤ x ≤ 0.22, chalcopyrite (copper pyrites) CuFeS ₂ , bornite Cu ₅ FeS ₄ , chalcocite Cu ₂ S or mixtures thereof, molybdenum (IV) sulfide molybdenum MoS ₂ , iron sulfides such as FeS / FeS ₂ , nickel sulfide such as NiS, lead sulfide such as PbS, zinc sulfide such as ZnS, CdS, CdSe, CdTe or mixtures thereof.

Examples of metals contained in the particle P are platinum and coin metals such as copper, silver, gold, iron, cobalt, nickel and their alloys.

The particle P may also include semiconducting materials selected from the group consisting of Ge, Si, α-Sn, C, for example, fullerenes, B, Se, Te, Bi, Ca, Sr, Ba, Yb, P, S, GaP, GaAs , InP, InSb, InAs, GaSb, GaN, AIN, InN, Al _x Ga _1-x As with x = 0 to 1, ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, Hg _1-x Cd _x Te where x is 0 to 1, BeSe, BeTe, HgS GaS, GaSe, GaTe, InS, InSe, InTe, CuInSe ₂ , CuInGaSe ₂ , CuInS ₂ , CuIn-GaS ₂ and / or SiC.

M

ausgewählt aus Co, Ni, Mn, Zn und Mischungen davon und

x

≤ 1,

hexagonalen Ferriten, beispielsweise Barium- oder Strontiumferrit MFe₁₂O₁₉ mit M = Ca, Sr, Ba, und Mischungen davon.In a preferred embodiment P is a particle selected from the group of magnetic particles, in particular selected from the group consisting of magnetic metals, for example iron, cobalt, nickel and mixtures thereof, ferromagnetic alloys of magnetic metals, magnetic iron oxides, for example magnetite, maghemite, cubic Ferrites of the general formula (II)

M ²⁺ _x Fe ²⁺ _1-x Fe ³⁺ ₂ O ₄ (II)

With

M

selected from Co, Ni, Mn, Zn and mixtures thereof and

x

≤ 1,

hexagonal ferrites, for example barium or strontium ferrite MFe ₁₂ O ₁₉ with M = Ca, Sr, Ba, and mixtures thereof.

In a particularly preferred embodiment of the present application, P is selected from the group consisting of magnetite Fe ₃ O ₄ , cobalt ferrite Co ²⁺ _x Fe ²⁺ _1-x Fe ³⁺ ₂ O ₄ with x ≤ 1, for example Co _0.25 Fe _2.75 O ₄ , and mixtures thereof.

The size of the particle present in the adduct of the general formula (IV) according to the invention is preferably from 5 nm to 100 μm, more preferably from 10 nm to 50 μm.

und Mischungen davon, besonders bevorzugt eine gegebenenfalls zumindest teilweise veresterte Phosphonsäuregruppe (Va) oder gegebenenfalls zumindest teilweise veresterte Phosphorsäuregruppe (Vb).In the general formula (VI), F is a functional group which, preferably selectively, binds to the particle P. F is for example selected from the group consisting of thiol group -SH, carboxylic acid group -CO ₂ H, optionally at least partially esterified phosphonic acid group -PO ₃ R ' ₂ with R' equal to hydrogen or C ₁ -C ₆ alkyl (Va), optionally at least partially esterified phosphoric acid group -O-PO ₃ R " ₂ with R" equal to hydrogen or C ₁ -C ₆ -alkyl (Vb), hydroxamate group (Vc), xanthate group (Vd)

and mixtures thereof, particularly preferably an optionally at least partially esterified phosphonic acid group (Va) or optionally at least partially esterified phosphoric acid group (Vb).

For oxidic particles P, especially functional groups selected from carboxylic acid group -CO ₂ H, optionally at least partially esterified phosphonic acid group -PO ₃ R ' ₂ with R' is hydrogen or C ₁ -C ₆ alkyl (Va), optionally at least partially esterified phosphoric acid group - O-PO ₃ R " ₂ with R" equal to hydrogen or C ₁ -C ₆ alkyl (Vb) or hydroxamate (Vc) suitable.

For sulfidic particles P, in particular functional groups selected from thiol group -SH and xanthate group (Vd) are suitable.

For platinum and coin metals, in particular the thiol group -SH is suitable.

B in the compound of the general formula (VI) denotes an alkyl radical having 1 to 6 carbon atoms, for example methyl, ethyl, propyl, butyl, for example n-butyl, pentyl or hexyl.

q in the compound of general formula (VI) is an integer of 1 to 1 x 10 ¹⁵ , preferably 1 x 10 ³ to 1 x 10 ¹² . q in the general formula (VI) describes the number of molecules of the polymeric compound bound to a particle P. These values correspond to a maximum occupation density of the particle P of 1.67 × 10 ^-6 mol / m ² , preferably 1 to 100% of the maximum occupation density. The number of polymer molecules attached to a particle P can be controlled by the amount of polymeric compound in the manufacturing process. The number of polymer molecules per particle P can be determined by methods known to the person skilled in the art, for example electron resonance analysis.

Functionalized particles of the general formula (VI) can be prepared by processes known to those skilled in the art, for example by contacting a solution of the polymeric compound of the general formula (III) in water or an organic solvent, preferably water, low molecular weight alcohols or ketones and washing the resulting Product with the appropriate solvent to remove excess polymeric compound.

Functionalized particles according to the general formula (VI) can be used to separate at least one first substance from a substance mixture comprising the at least one first substance and at least one second substance, for example by the process according to the invention. The present invention therefore also relates to the use of a functionalized particle according to the general formula (VI) for the separation of mixtures of substances. With respect to the mixtures and the other parameters of the separation of substances, the above applies.

Examples: Example 1: Preparation of the hydrophilic / hydrophobic switchable modifier

The functionalizing agent is prepared by reacting an alkoxylate of the formula n-Bu- (PO) ₂₂ -OH (Pluriol A1350P, BASF SE) with polyphosphoric acid (ThermPhos) by methods known to the person skilled in the art. The transition range from hydrophilic to hydrophobic is found at 15-26 ° C.

The alkoxylate n-Bu- (PO) ₂₂ -OH used has an OH number (OHN) of 46.3 and a molecular weight of 1213 g / mol.

Alkoxylate and polyphosphonic acid are reacted at 80 ° C. for 31.7 h. After 29 h, a conversion of 72% is determined by means of titration, the acid number is 102 mg KOH / g.

Example 2 Production of the Hydrophilic / Hydrophobic Switchable Magnetic Particle

A suspension of 100 mg of the product obtained in Example 1 in 10 ml of water (about 10 ° C) is prepared. 2 g of magnetite (Magnetic Black 345, BASF, 0 4 μm) are stirred with the suspension for 15 minutes, filtered off, washed with 50 ml of cold water (T <10 ° C.) and dried in vacuo at 80 ° C.

Example 3: Separation experiment

A suspension of 54 g of quartz powder (SiO ₂ , Microsil type S8 from Euroquarz), 2 g of Cu ₂ S, (325 mesh, Aldrich) and 1000 g of process water is placed in a beaker with stirring. 0.13 g of potassium 1-octylxanthate and 0.08 g of Shellsol 40 are added to the suspension. The suspension is stirred for 1 h with a paddle stirrer (35 rpm) and then heated to 45 ° C. with stirring. 2 g of the hydrophilic / hydrophobic switchable magnetite from Example 2 are added with stirring. The suspension is stirred for a further 30 minutes at 45.degree.

Subsequently, the suspension is guided past several permanent magnets behind glass. The magnetic components are held on the magnet, the remainder of the suspension is collected, filtered off, dried and analyzed for Cu content (fraction A1).

After removal of the permanent magnets, the magnetic components are suspended in cold water (10 ° C.) and redirected past the magnet. The effluent is collected, filtered off, dried and analyzed for Cu content (fraction A2).

The fraction held on the magnet is examined in the same way (fraction R). It can be stated that the total amount of copper found (= 100% by weight) is distributed among the fractions as follows: A1 A2 R 15.5% by weight 39.5% by weight 45.0% by weight

On the other hand, 95% of the quartz powder used can be found in fraction A1. This results in a clear accumulation of copper in the fraction A2.

Claims (10)

1. A process for separating at least one first material selected from the group consisting of sulfidic ores, oxidic and/or carbonate-comprising ores and mixtures thereof or noble metals and their compounds, from a mixture comprising this at least one first material and at least one second material, which comprises the following steps:

   (A) contacting of the mixture comprising the at least one first material and at least one second material with at least one selective hydrophobicizing agent in the presence of a suspension medium so that an adduct is formed from the at least one hydrophobicizing agent and the at least one first material but not with the at least one second material,

   (B) contacting of the adduct from step (A) with at least one magnetic particle which is functionalized on the surface with at least one polymeric compound having a transition temperature LCST (lower critical solution temperature) at a temperature at which the polymeric compound has hydrophobic character so that the adduct from step (A) and the at least one functionalized magnetic particle agglomerate,

   (C) optionally addition of further suspension medium to the mixture obtained in step (B),

   (D) separation of the agglomerate present in the suspension from step (B) or (C) from the suspension by application of a magnetic field,

   (E) dissociation of the agglomerate separated off in step (D) by setting of a temperature at which the polymeric compound has hydrophilic character in order to obtain the at least one first material.
2. The process according to claim 1, wherein the at least one polymeric compound is selected from the group consisting of polyvinyl ethers, poly-N-alkylacrylamides, poly-N-vinylcaprolactams, copolymers based on alkylene oxides and mixtures thereof.
3. The process according to claim 1 or 2, wherein the at least one polymeric compound is a compound of the general formula (III)
   
           F-[(EO)_x-(PO)_y-(BuO)_z]-B     (III)
   
   where

   F is a functional group which binds selectively to the at least one magnetic particle,

   B is an alkyl radical having from 1 to 6 carbon atoms,

   EO is ethylene oxide,

   PO is propylene oxide,

   BuO is butylene oxide,

   x is an integer or fraction from 0 to 130,

   y is an integer or fraction from 0 to 130, and

   z is an integer or fraction from 0 to 130,

   where 1 ≤ x+y+z ≤ 130.
4. The process according to any of claims 1 to 3, wherein the at least one second material is selected from the group consisting of oxidic metal compounds, hydroxidic metal compounds and mixtures thereof.
5. The process according to any of claims 1 to 4, wherein the at least one magnetic particle is selected from the group consisting of magnetic metals, ferromagnetic alloys of magnetic metals, magnetic iron oxides, cubic ferrites of the general formula (II)
   
           M²⁺ _xFe²⁺ _1-xFe³⁺ ₂O₄     (II)
   
   where

   M is selected from among Co, Ni, Mn, Zn and mixtures thereof and

   x ≤ 1,

   hexagonal ferrites and mixtures thereof.
6. The process according to any of claims 1 to 5, wherein the LCST of the polymeric compound used is from -10 to 100°C.
7. The process according to any of claims 1 to 6, wherein step (B) is carried out at a temperature which is greater than the LCST of the polymeric compound and lower than the boiling point of the suspension medium used.
8. The process according to any of claims 1 to 7, wherein step (E) is carried out at a temperature which is above the melting point of the suspension medium used and below the LCST of the polymeric compound.
9. A functionalized particle of the general formula (VI)
   
           P-{F-[ (EO)_x-(PO)_y-(BuO)_z]-B}_q     (VI),
   
   where

   P is a particle comprising at least one metal or semimetal,

   F is a functional group,

   B is an alkyl radical having from 1 to 6 carbon atoms,

   EO is ethylene oxide,

   PO is propylene oxide,

   BuO is butylene oxide,

   x is an integer or fraction from 0 to 130,

   y is an integer or fraction from 0 to 130,

   z is an integer or fraction from 0 to 130, where 1 ≤ x+y+z ≤ 130, and

   q is an integer from 1 to 1 * 10¹⁵.
10. The use of a functionalized particle according to claim 9 for the separation of mixtures of materials.