WO2017216130A1

WO2017216130A1 - Use of phosphated and sulfated aromatic resins as grinding aids for ores and minerals

Info

Publication number: WO2017216130A1
Application number: PCT/EP2017/064341
Authority: WO
Inventors: Kristina BRANDT; Joachim Dengler; Dunja Hirsemann; Tatiana MITKINA; Nina Susanne HILLESHEIM; Adrian Mauricio VILLANUEVA BERINDOAGUE
Original assignee: Basf Se
Priority date: 2016-06-14
Filing date: 2017-06-13
Publication date: 2017-12-21

Abstract

The present invention relates to the use of phosphated and sulfated aromatic polycondensates as grinding aid for an ore or mineral, the polycondensate comprising an optionally substituted 5- to 10-membered aromatic or heteroaromatic compound, wherein this compound has, on average, 1 to 300 oxyethylene and/or oxypropylene groups per molecule, which groups are connected to the aromatic or heteroaromatic compound via an oxygen (O) or nitrogen (N) atom; an optionally substituted 5- to 10-membered aromatic or heteroaromatic compound, wherein this compound has, on average, 1 to 300 C₂-C₂₀ oxyalkylene groups per molecule, which groups are connected to the aromatic or heteroaromatic compound via an oxygen (O) or nitrogen (N) atom, and wherein the oxyethylene and/or oxypropylene groups are terminated by -SO₃M_s, -OSO₃M_s, -ΡΟ₃Μ_p, or -ΟΡΟ₃Μ_p, wherein M is selected from the group consisting of hydrogen, alkali metals, alkaline earth metals, ammonium and organic ammonium ions, s may be 0.5, or 1, and p may be 1 or 2; and an aldehyde or aldehyde source; as well as optionally at least (a) an aromatic compound selected from the group consisting of phenols, phenol ethers, naphthols, naphthol ethers, aniline, and furfuryl alcohol, and/or (b) an melamine forming compound selected from the group consisting of melamine or a derivative thereof, urea or a derivative thereof, and carboxamides.

Description

Use of phosphated and sulfated aromatic resins as grinding aids for ores and minerals

Field of the invention

The present invention relates to the use of phosphated and sulfated aromatic polycondensates as grinding aid for an ore or mineral, the polycondensate comprising an optionally substituted 5- to 10-membered aromatic or heteroaromatic compound, wherein this compound has, on average, 1 to 300 C2-C20 oxyalkylene groups per molecule, which groups are connected to the aromatic or heteroaromatic compound via an oxygen (O) or nitrogen (N) atom; an optionally substituted 5- to 10-membered aromatic or heteroaromatic compound, wherein this compound has, on average, 1 to 300 C2-C20 oxyalkylene groups per molecule, which groups are connected to the aromatic or heteroaromatic compound via an oxygen (O) or nitrogen (N) atom, and wherein the oxyalkylene groups are terminated by -SO3MS, -OSO3MS, -ΡΟβΜρ, or -ΟΡΟβΜρ, wherein M is selected from the group consisting of hydrogen, alkali metals, alkaline earth metals, ammonium and organic ammonium ions, s may be 0.5, or 1 , and p may be 1 or 2; and an aldehyde or an aldehyde source; as well as optionally at least (a) an aromatic compound selected from the group consisting of phenols, phenol ethers, naphthols, naphthol ethers, aniline, and furfuryl alcohol, and/or (b) an melamine forming compound selected from the group consisting of melamine or a derivative thereof, urea or a derivative thereof, and carboxamides.

Background of the invention

Bauxite is one of the widely used natural ores for aluminum production and consists primarily of aluminium oxide-hydroxides (minerals gibbsite, boehmite and diaspore) and iron oxide- hydroxide phases (minerals Goethite and Hematite). In the aluminum processing industry the aluminum oxide-hydroxide phases are being digested by caustic solution in a so-called Bayer process and recrystallized as pure aluminum hydroxide. To make the digestion process as effective as possible the bauxite ore is milled before the digestion step in a wet grinding process using ball and/or rod mills. The bauxite grinding process is usually carried out in spent Bayer liquor, which is a returned solution after the precipitation stage of aluminum hydroxide. Spent Bayer liquor is an extremely alkaline and saline solution, which mainly consists of sodium hydroxide, sodium aluminates, other dissolved salts and organic material. Therefore, the suspension of bauxite in the used Bayer liquor (so-called Bayer slurry) has also a very high salinity and pH-value of 13 to 14.

Bauxite grinding is a very energy consuming step of the whole Bayer process, and the throughput of the mill is limited by the pumpability and viscosity of the Bayer slurry. The latter is always very high due to the high solids content used (50 % by wt. and higher of bauxite).

The use of additives to the Bayer slurry at the grinding step of Bayer process is not very widely known. As a rare example of an additive to the Bayer process for bauxite grinding, the bauxite grinding aid "Rheotec GA2" Tecnochem may be mentioned. CYFLOC^® BXD of Cytec may also be mentioned as an example of a grinding additive. However, CYFLOC^® BXD is rather used for absorbing the free moisture content of the bauxite and for agglomerating fine particles, than to directly influence the rheology of the Bayer slurry. The use of non-ionic surfactants, polyglycols, polyglycol ethers, anionic surfactants, and anionic polymers to increase the pumpability of the Bayer slurry is suggested, e.g., in U.S. patent No. 8,628,737 B2.

The general use of polyacrylic or polymethacrylic acid or an anionic derivative thereof as a grinding aid for coal or ores in a liquid medium was suggested by U.S. patent No. 4,162,044.

Finally, also the use of additives in the wet grinding of bauxite to reduce the viscosity of the slurry was suggested, e.g., in WO 2009/093270 A1. Here, an aqueous suspension of ethylene oxide/propylene oxide copolymer, dioctyl sulphosuccinate and butylene glycol is suggested as additive.

Despite these efforts to make the grinding of bauxite more effective, there still exists a need for a grinding aid that allows for a more effective grinding process.

Summary of the invention

It was now surprisingly found that the polycondensates of the present disclosure allow for an increase of the solid content of an ore or mineral, such as bauxite, in an aqueous slurry, e.g. in the Bayer slurry, while maintaining the slurry viscosity, thus allowing for a increased throughput of ore or mineral in the grinding process at the same grinding energy.

The present description relates to the use of a polycondensate as grinding aid for an ore or mineral.

In a first aspect, the present disclosure relates to the use of a polycondensate as grinding aid for ores and minerals, wherein the polycondensate is a monomer-based condensation product comprising at least:

A) an optionally substituted 5- to 10-membered aromatic or heteroaromatic compound, wherein this compound has, on average, 1 to 300 C2-C20 oxyalkylene groups per molecule, which groups are connected to the aromatic or heteroaromatic compound via an oxygen (O) or nitrogen (N) atom;

B) an optionally substituted 5- to 10-membered aromatic or heteroaromatic compound, wherein this compound has, on average, 1 to 300 C2-C20 oxyalkylene groups, which groups are connected to the aromatic or heteroaromatic compound via an oxygen (O) or nitrogen (N) atom, and wherein the oxyalkylene groups are terminated by -S0₃Ms, -OS0₃M_s, -P0₃M_p, or -OP0₃M_p, wherein M is selected from the group consisting of hydrogen, alkali metals, alkaline earth metals, ammonium and organic ammonium ions, s may be 0.5, or 1 , and p may be 1 or 2; and

C) an aldehyde or an aldehyde source; as well as

D) optionally at least (a) an aromatic compound selected from the group consisting of phenols, phenol ethers, naphthols, naphthol ethers, aniline, and furfuryl alcohol, and/or (b) an melamine forming compound selected from the group consisting of melamine or a derivative thereof, urea or a derivative thereof, and carboxamides.

Preferred embodiments of this aspect are disclosed herein below, in particular in connection with the Examples, as well as in the appendant claims and Figures. Figures

The present disclosure also refers to the following Figures, wherein:

Fig. 1 shows the shear stress at increasing shear rate of a Bayer slurry with ABL with and without Additive 1 according to Example 1 a;

Fig. 2 shows the shear stress at increasing shear rate of a Bayer slurry with ABL with and without Additive 3 according to Example 1 a;

Fig. 3 shows the shear stress at increasing shear rate of a Bayer slurry with SBL with and without Additive 1 according to Example 1 b;

Fig. 4 shows the shear stress at increasing shear rate of a Bayer slurry with SBL with and without Additive 1 according to Example 1 b;

Fig. 5 shows the shear stress at increasing shear rate of a Bayer slurry with ABL with and without Additive 2 according to Example 2a;

Fig. 6 shows the shear stress at increasing shear rate of a Bayer slurry with SBL with and without Additive 4 according to Example 2b;

Fig. 7 shows the shear stress at increasing shear rate of a Bayer slurry with SBL with and without Additive 4 according to Example 2b;

Fig. 8 shows the shear stress at increasing shear rate of a Bayer slurry with SBL with and without Additives 5 and 6 according to Example 2b;

Fig. 9 shows the shear stress at increasing shear rate of a Bayer slurry with SBL with and without Additive 1 and different amounts of bauxite according to Example 3;

Fig. 10 shows the shear stress at increasing shear rate of a Bayer slurry with SBL with and without Additive 2 and different amounts of bauxite according to Example 4;

Fig. 1 1 shows the particle size distribution of bauxite ore sample;

Fig. 12 shows mill discharge particle size distributions for the tests 1 -3; and Detailed description of the invention

The present description relates to the use of a polycondensate as grinding aid for an ore or mineral. Without being bound to any theory, it is assumed that the polycondensates of the description when used as grinding aid in a process for grinding an ore or mineral modify the rheology of the grinding suspension or slurry. Accordingly, in the present description, the terms "grinding aid" and "rheology modifier" are used interchangeably.

Furthermore, also the terms "grinding suspension", "grinding slurry", "suspension", and "slurry" are used interchangeably in the present description when referring to a suspension of solid particles used in a grinding process, such as the Bayer process for grinding bauxite.

A) an optionally substituted 5- to 10-membered aromatic or heteroaromatic compound, wherein this compound has, on average, 1 to 300 C2-C20 oxyalkylene groups, which groups are connected to the aromatic or heteroaromatic compound via an oxygen (O) or nitrogen (N) atom;

B) an optionally substituted 5- to 10-membered aromatic or heteroaromatic compound, wherein this compound has, on average, 1 to 300 C2-C20 oxyalkylene groups, which groups are connected to the aromatic or heteroaromatic compound via an oxygen (O) or nitrogen (N) atom, and wherein the oxyalkylene groups are terminated by -S0₃Ms, -OS0₃Ms, -P0₃M_p, or -OP0₃M_p, wherein M is selected from the group consisting of hydrogen, alkali metals, alkaline earth metals, ammonium and organic ammonium ions, s may be 0.5, or 1 , and p may be 1 or 2; and

C) an aldehyde or an aldehyde source; as well as

optionally at least (a) an aromatic compound selected from the group consisting of phenols, phenol ethers, naphthols, naphthol ethers, aniline, and furfuryl alcohol, and/or (b) an melamine forming compound selected from the group consisting of melamine or a derivative thereof, urea or a derivative thereof, and carboxamides.

In other words, the polycondensate of the present disclosure is a monomer-based condensation product composed of at least three (monomeric) components A, B and C, and optionally contains also (monomeric) component D. However, in the broadest sense of the

polycondensate, also other components not explicitly mentioned, and also two or more different components A, B and/or C may be used to prepare the polycondensate.

In a preferred embodiment, the polycondensate consists of components A, B and C, and optionally component D.

In another preferred embodiment, the polycondensate consists of components A, B and C, and optionally D, wherein only a single representative of each component is present. In other words, only one species of compounds A, B, C, and optionally D is present in the

polycondensate in accordance with this embodiment of the present disclosure.

The preferred embodiments of the present disclosure relating to the different components, the amounts thereof, and also additional compounds used in the use are independent of each other, and these embodiments are thus freely combinable as understood by the skilled person. As an example, if one preferred embodiment relates to a specific aromatic compound for component A, and another preferred embodiment relates to a specific component C, a still other preferred embodiment relates to the combination thereof, i.e., the specific aromatic compound for component A in combination with the specific component C.

In a preferred embodiment, component A is an unsubstituted 5- to 10-membered aromatic or heteroaromatic compound, wherein this compound has, on average, 1 to 300 oxyalkylene groups per molecule, which groups are connected to the aromatic or heteroaromatic compound via an oxygen (O) or nitrogen (N) atom.

In another preferred embodiment, component A is a substituted 5- to 10-membered aromatic or heteroaromatic compound, wherein this compound has, on average, 1 to 300 C2-C20 oxyalkylene groups, preferably C2-C5 oxyalkylene units, more preferably C2-C₃ oxyalkylene units per molecule, which groups are connected to the aromatic or heteroaromatic compound via an oxygen (O) or nitrogen (N) atom, wherein the aromatic or heteroaromatic compound of component A comprises at least one substituent selected from the group consisting of OH, OR¹ , NH2, NHR¹ , NR¹2, and C1-C10 alkyl, wherein the C1-C10 alkyl may optionally be substituted by phenyl and/or 4-hydroxy phenyl, and R¹ is a C1-C4 alkyl. In other words, the 5- to 10-membered aromatic or heteroaromatic compound is substituted by, on average, 1 to 300 C2-C20

oxyalkylene groups, preferably C2-C5 oxyalkylene units, more preferably C2-C3 oxyalkylene units per molecule, and additionally by at least one substituent selected from the group consisting of OH, OR¹ , NH₂, NHR¹ , NR¹2, and C1-C10 alkyl, wherein the C1-C10 alkyl may optionally be substituted by phenyl and/or 4-hydroxy phenyl, and R¹ is a C1-C4 alkyl.

In another preferred embodiment, the aromatic or heteroaromatic compound of component A and/or B is, independently, a phenol derivative, a naphthol derivative, an aniline derivative, or a furfuryl alcohol derivative, or is derived from a compound selected from the group consisting of phenol, cresol, resorcinol, nonylphenol, methoxyphenol, naphthol, methylnaphthol,

butylnaphthol, bisphenol A, aniline, methylaniline, hydroxyaniline, methoxyaniline, furfuryl alcohol and salicylic acid. When component A or B is "derived" from a compound or is a

"derivative" thereof, said aromatic or heteroaromatic compound is substituted by the PEG or PPG chain, and in particular optionally substituted by at least one substituent selected from the group consisting of OH, OR¹ , NH2, NHR¹ , NR¹2, and C1-C10 alkyl, wherein the C1-C10 alkyl may optionally be substituted by phenyl and/or 4-hydroxy phenyl, and R¹ is a C1-C4 alkyl.

In one embodiment, the substituted aryl or heteroaryl compound is a phenol derivative, a naphthol derivative, an aniline derivative, or a furfuryl alcohol derivative. In another

embodiment, the substituted aryl or heteroaryl compound is derived from a compound selected from the group consisting of phenol, cresol, resorcinol, nonylphenol, methoxyphenol, naphthol, methylnaphthol, butylnaphthol, bisphenol A, aniline, methylaniline, hydroxyaniline,

methoxyaniline, furfuryl alcohol and salicylic acid.

In a still further preferred embodiment, the aromatic or heteroaromatic compound of

components A and B are derived from identical aromatic or heteroaromatic compounds, but having different substituents, in particular different polyalkyleneglycol substituents, such as PEG or PPG. In a further preferred embodiment, the aromatic or heteroaromatic compound of components A and B are derived from identical aromatic or heteroaromatic compounds both having polyalkyleneglycol substituents, with the exception that compound B additionally holds the terminal group selected form the group consisting of -SO3MS, -OSO3MS, -Ρθ3Μ_ρ,

and -OPOsMp. In these embodiments, the aromatic or heteroaromatic compounds of components A and B are identical, while A and B differ from each other in their terminal groups. While component A has no terminal group, component B holds a terminal group selected form the group consisting of -S0₃M_s, -OS0₃M_s, -P0₃M_p, and -OP0₃M_p.

In accordance with the present disclosure, the aromatic or heteroaromatic compound of component A and/or B has, on average, 1 to 300 oxyalkylene groups per molecule, which groups are connected to the aromatic or heteroaromatic compound via an oxygen (O) or nitrogen (N) atom. In one embodiment, the compound of component A and/or the compound of component B has, on average, 1 to 20 oxyalkylene groups per molecule, preferably 1 to 15 oxyalkylene groups per molecule, further preferably 1 to 10 oxyalkylene groups per molecule, further preferably 1 to 8 oxyalkylene groups per molecule, still further preferably 1 to 5 oxyalkylene groups per molecule, still further preferably 1 to 4 oxyalkylene groups per molecule. In another, independent embodiment, which, however, may be specifically combined with the previous embodiment, the oxyalkylene groups are C2-C10 oxyalkylene units, preferably C2-C5 oxyalkylene units, more preferably C2-C4 oxyalkylene units, and even more preferably C2-C3 oxyalkylene (i.e., oxyethylene and/or oxypropylene groups) units.

The compound of component A and/or the compound of component B may thus, on average, have 1 to 20 oxyalkylene groups per molecule, wherein the oxyalkylene groups are C2-C10 oxyalkylene units, preferably C2-C5 oxyalkylene units, more preferably C2-C4 oxyalkylene units, and even more preferably C2-C3 oxyalkylene (i.e., oxyethylene and/or oxypropylene groups) units. In another embodiment, the compound of component A and/or the compound of component B may thus, on average, have 1 to 15 oxyalkylene groups per molecule, wherein the oxyalkylene groups are C2-C10 oxyalkylene units, preferably C2-C5 oxyalkylene units, more preferably C2-C4 oxyalkylene units, and even more preferably C2-C3 oxyalkylene (i.e., oxyethylene and/or oxypropylene groups) units. In another embodiment, the compound of component A and/or the compound of component B may thus, on average, have 1 to 10 oxyalkylene groups per molecule, wherein the oxyalkylene groups are C2-C10 oxyalkylene units, preferably C2-C5 oxyalkylene units, more preferably C2-C4 oxyalkylene units, and even more preferably C2-C3 oxyalkylene (i.e., oxyethylene and/or oxypropylene groups) units. In another embodiment, the compound of component A and/or the compound of component B may thus, on average, have 1 to 8 oxyalkylene groups per molecule, wherein the oxyalkylene groups are C2-C10 oxyalkylene units, preferably C2-C5 oxyalkylene units, more preferably C2-C4 oxyalkylene units, and even more preferably C2-C3 oxyalkylene (i.e., oxyethylene and/or oxypropylene groups) units. In another embodiment, the compound of component A and/or the compound of component B may thus, on average, have 1 to 5 oxyalkylene groups per molecule, wherein the oxyalkylene groups are C2-C10 oxyalkylene units, preferably C2-C5 oxyalkylene units, more preferably C2-C4 oxyalkylene units, and even more preferably C2-C3 oxyalkylene (i.e., oxyethylene and/or oxypropylene groups) units. In another embodiment, the compound of component A and/or the compound of component B may thus, on average, have 1 to 4 oxyalkylene groups per molecule, wherein the oxyalkylene groups are C2-C10 oxyalkylene units, preferably C2-C5 oxyalkylene units, more preferably C2-C4 oxyalkylene units, and even more preferably C2-C3 oxyalkylene (i.e., oxyethylene and/or oxypropylene groups) units.

In another embodiment, the polyalkyleneglycol is connected to the aromatic or heteroaromatic compound of component A and/or B via an oxygen (O) atom.

In still another embodiment, the aromatic or heteroaromatic compound of component A is terminated by a hydroxy (-OH) group.

Components B as used in the polycondensate of the present disclosure holds a terminal group selected form the group consisting of -S0₃M_s, -OS0₃M_s, -P0₃M_p, and -OP0₃M_p. Based on the terminal group, the polycondensates may also be termed as sulfated (i.e., carrying a -SO3MS, or -OSO3MS group) or phosphated (i.e., carrying a -POsMp, or -ΟΡΟβΜρ group) polycondensate. As detailed herein, the terminal group is attached to the polyalkyleneglycol at component B. In a preferred embodiment, the polyalkyleneglycol is terminated by -ΡΟβΜρ, and -ΟΡΟβΜρ, further preferably terminated by -ΟΡΟβΜρ, wherein M is selected from the group consisting of hydrogen, alkali metals, alkaline earth metals, ammonium and organic ammonium ion and p is 1/x and x is a charge of M cation, still further preferably wherein M is K or Na, preferably Na, and p is 2.

The polycondensate of the present disclosure may optionally contain component D, which may be selected as (a) an aromatic compound selected from the group consisting of phenols, phenol ethers, naphthols, naphthol ethers, aniline, and furfuryl alcohol. In one embodiment, said aromatic compound of component D comprises at least one substituent selected from the group consisting of OH, NH₂, OR², NHR², NR² ₂, COOH, Ci-C₄ alkyl, S0₃H, OS0₃H, P0₃H₂, and OPO3H2, wherein the C1-C4 alkyl may be optionally substituted by phenyl and/or 4-hydroxy phenyl, and R² is a C1-C4 alkyl which may be optionally substituted by a substituent selected from the group consisting of OH, COOH, S0₃H, PO3H2, and OPO3H2. In other words, the aromatic group may optionally be substituted by any of these substituents.

In still another embodiment, the aromatic compound of component D is a compound selected from the group consisting of phenol, phenoxyacetic acid, phenoxyethanol, phenoxyethanol phosphate, phenoxydiglycol, phenoxy(poly)ethyleneglycol phosphate, methoxyphenol, resorcinol, cresol, bisphenol A, nonylphenol, aniline, methylaniline, N-phenlyldiethanolamine, N- phenyl-N,N-dipropanoic acid, N-phenyl-N,N-diacetic acid, N-phenyldiethanolamine diphosphate, phenolsulphonic acid, anthranilic acid, succinic monoamide, furfuryl alcohol, melamine, and urea.

The polycondensate of the present disclosure is prepared using at least one aldehyde or an aldehyde source as component C. In one embodiment, component C is selected from the group consisting of formaldehyde, paraformaldehyde, 1 ,3,5-trioxane, acetaldehyde,

paraldehyde, glyoxylic acid, furfurylaldehyde, benzaldehyde, benzaldehydesulphonic acid and benzaldehydedisulphonic acid. In another embodiment, component C is selected from the group consisting of formaldehyde, paraformaldehyde, 1 ,3,5-trioxane, acetaldehyde, and paraldehyde. In a preferred embodiment, component C is formaldehyde or paraformaldehyde, preferably formaldehyde.

The component C reacts in a polycondensation reaction with components A and B, and optionally component D. In one embodiment, the molar ratio of (component C) : (component A, component B and optionally component D) is 1 : 0.5 to 1 : 2, and preferably 1 : 0.9 to 1 : 1 .1 . Components A and B of the polycondensate essentially differ in that component B is terminated by a S or P containing group as defined herein, and component A is not terminated by such group. Both components A and B may be used in any ratio. In one embodiment, the molar ratio of components A : B is from 10 : 1 to 1 : 10, preferably from 1 :1 to 1 :5.

Optional component D may also be used in any amount in the polycondensate, however, in one embodiment, the molar ratio of components A : D is from 10 : 1 to 1 : 10.

In general, if the molar ratio of two components is given, it refers to the ratio of the two components as present in the reaction mixture.

The polycondensate as used in accordance with the present disclosure may have a molecular weight Mw of up to 50 000 g/mol, preferably up to 30 000 g/mol, and further preferably of 5 000 to 25 000 g/mol.

In accordance with the present disclosure, the polycondensates are used as aid for grinding ores and/or minerals. It is understood that the polycondensates disclosed herein may be used alone or as a mixture of different polycondensates, and even in mixture with other grinding aids.

In one embodiment, the polycondensate is used in combination with at least one poly(ethylene glycol), preferably poly(ethylene glycol) methyl ether. In a still further preferred embodiment, the poly(ethylene glycol) methyl ether has a Mn of about 500 g/mol.

When used in combination with a poly(ethylene glycol), the poly(ethylene glycol) is used in an amount of from 1 to 50 % by wt., preferably 20 to 40 % by wt, based on the total amount of polycondensate as used in the grinding process.

It is preferred according to the present disclosure that the polycondensate is used as grinding aid in an aqueous suspension or aqueous slurry of an ore and/or mineral. The ore or mineral is thus suspended in water as solvent, and the grinding is a wet grinding. The polycondensate is then added to the slurry or suspension, or it may be present in the water prior to the addition of the ore or mineral.

In one embodiment, the polycondensate is used in the aqueous suspension or aqueous slurry in an amount of from 0.001 % to 5 % by wt., preferably of from 0.01 % to 0.5 % by wt., based on the total amount of ore or mineral. The amount of polycondensate added is thus preferably determined based on the amount of ore or mineral, and not based on the amount of solvent, such as water.

The polycondensate of the present disclosure may be used as grinding aid for any ore or mineral. In one embodiment, the ore or mineral is selected from the group of an Al containing ore or mineral, a Fe containing ore or mineral, a Cu containing ore or mineral, a Mo containing ore or mineral, an Au containing ore or mineral, or mixtures thereof. In a preferred embodiment, the ore or mineral is an Al containing ore or mineral, and preferably the polycondensate is used as grinding aid to improve the grinding of a bauxite containing slurry during the grinding stage of an alumina extraction process, preferably in an alumina extraction process using a Bayer process.

For the milling or grinding of the ore or mineral, any conventionally known process may be used. As such, in one embodiment, the ore or mineral may be ground in a wet milling process using milling balls for grinding.

It was now surprisingly found that the polycondensates of the present disclosure allow for an increase of the solid content of an ore or mineral, such as bauxite, in an aqueous slurry, e.g. in the Bayer slurry, while maintaining the slurry viscosity, thus allowing for a increased throughput of ore or mineral in the grinding process at the same grinding energy. This is illustrated in more detail in the Examples below. Definitions

The grinding aids of the present application are used for grinding ores and minerals. As used herein, the term "ores and minerals" refers to any metal containing ore or mineral. In a preferred embodiment, the term "ores and minerals" does not comprise mineral binders, such as clinker, cement, slag and fly ash. In another embodiment, the ores and minerals are selected from the group consisting of Al containing ore or mineral, Fe containing ore or mineral, Cu containing ore or mineral, Mo containing ore or mineral, Au containing ore or mineral and mixtures thereof. In another preferred embodiment, the term "ores and minerals" comprises aluminum and/or iron ores and minerals, in particular aluminum ores and minerals, preferably bauxite. In still another preferred embodiment, the term "ores and minerals" refers to aluminum and/or iron ores and minerals, in particular aluminum ores and minerals, preferably bauxite.

As used herein, the term "optionally substituted 5- to 10-membered aromatic or heteroaromatic compound, wherein this compound has, on average, 1 to 300 oxylakylene groups per molecule, which groups are connected to the aromatic or heteroaromatic compound via an oxygen (O) or nitrogen (N) atom" refers to a (5- to 10-membered)aryl or (5- to 10-membered)heteroaryl which is - on average - substituted by one or more, preferably by one substituent which comprises the 1 to 300 oxylakylene groups. Said substituent being composed of oxyalkylene groups

("substituent of oxylakylene groups") is attached to the aryl or heteroaryl via an oxygen (O) or nitrogen (N) atom. In one embodiment, the substituent of oxyalkylene groups has 1 to 300 oxyalkylene groups, preferably 2 to 280 oxyalkylene groups, further preferably 10 to 200 oxyalkylene groups. In another embodiment, the substituent of oxyalkylene groups has at least 2, at least 3, at least 4, or at least 5 oxyalkylene groups. In still another embodiment, the substituent of oxyalkylene groups has 1 to 21 oxyalkylene groups, preferably 1 to 18, further preferably 2 to 18 oxyalkylene groups, further preferably 2 to 12 oxyalkylene groups, further preferably 3 to 12 oxyalkylene groups, further preferably 3 to 6 oxyalkylene groups. In still another embodiment, the substituent of oxyalkylene groups has 1 to 20 oxyalkylene groups per molecule, preferably 1 to 15 oxyalkylene groups per molecule, further preferably 1 to 10 oxyalkylene groups per molecule, further preferably 1 to 8 oxyalkylene groups per molecule, still further preferably 1 to 5 oxyalkylene groups per molecule.

As used herein, the term "optionally substituted 5- to 10-membered aromatic or heteroaromatic compound" refers to a (further) substitution of the 5- to 10-membered aromatic or

heteroaromatic compound. In other words, in addition to the substitution by oxyalkylene groups, the aryl or heteroaryl may optionally be substituted. The substituent may be selected form the group consisting of -OH, -OR¹, -NH₂, -NHR¹, -NR¹ ₂, C1-C10 alkyl, -SO3H, -COOH, -PO3H2, and -OPO3H2, wherein the C1-C10 alkyl may optionally be substituted by phenyl and/or 4- hydroxy phenyl, and R¹ is a C1-C4 alkyl.

As used herein, the term "which groups are connected to the aromatic or heteroaromatic compound via an oxygen (O) or nitrogen (N) atom" refers to the connection of the oxyalkylene groups to the aryl or heteroaryl group. The oxyalkylene groups may either be directly bound via their oxygen atom to the aryl or heteroaryl, or they may connect to a hydroxy or amine substituent being present at the aryl or heteroaryl. In the first case, the oxyalkylene chain is terminated by a CH3 group (for component A), and in the latter case, the oxyalkylene is terminated by a hydroxy group (for component A). Furthermore, in the latter case where the substituent is an amine, the oxyalkylene chain is connected "via a nitrogen (N) atom" to the aryl or heteroaryl. For components B, the oxyalkylene is terminated by -SO3MS

(sulfonate), -OS0₃M_s (sulfate), -P0₃M_p (phosphonate), or -OP0₃M_p (phosphate) when the oxyalkylene groups are directly bound via their oxygen atom, and by -SO3MS (sulfonate), or -PO3M_P (phosphonate) else since an oxygen atom is already present at the end of the oxyalkylene chain. As used herein, the term "(5- to 10-membered)aryl" or "5- to 10-membered aromatic compound" refers to an aromatic carbocyclic ring containing 5 to 10 carbon atoms, including both mono- and bicyclic ring systems. Representative (5- to 10-membered)aryl groups include phenyl, indenyl, naphthyl, and the like. In a preferred embodiment, the aryl is phenyl or naphthyl, further preferably phenyl. The "(5- to 10-membered)aryl" or "5- to 10-membered aromatic compound" is also referred to as aryl in the present application.

As used herein, the term "(5- to 10-membered)heteroaryl" or "5- to 10-membered

heteroaromatic compound" refers to an aromatic heterocycle ring of 5 to 10 members, including both mono- and bicyclic ring systems, where at least one carbon atom (of one or both of the rings) is replaced with a heteroatom, or at least two carbon atoms of one or both of the rings are replaced with a heteroatom independently selected from nitrogen (N), oxygen (O), sulfur (S) and phosphor (P). In one embodiment, 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, and further preferably 1 or 2 carbon atoms are replaced by a heteroatom. In one embodiment, one of the bicyclic (5- to 10-membered)heteroaryl rings contains at least one carbon atom. In another embodiment, both of the bicyclic (5- to 10-membered)heteroaryl rings contain at least one carbon atom. Representative (5- to 10-membered)heteroaryls include pyridyl, furyl, benzofuranyl, thiophenyl, benzothiophenyl, quinolinyl, isoquinolinyl, pyrrolyl, indolyl, oxazolyl, benzoxazolyl, imidazolyl, benzimidazolyl, thiazolyl, benzothiazolyl, isoxazolyl, oxadiazolinyl, pyrazolyl, isothiazolyl, pyridazinyl, pyrimidyl, pyrimidinyl, pyrazinyl, thiadiazolyl, triazinyl, thienyl, thiadiazolyl, cinnolinyl, phthalazinyl, quinazolinyl, and the like. In a preferred embodiment, the heteroaryl is pyridyl, furyl, benzofuranyl, thiophenyl, benzothiophenyl, quinolinyl, and

isoquinolinyl, preferably pyridyl. The "(5- to 10-membered)heteroaryl" or "5- to 10-membered heteroaromatic compound" is also referred to as heteroaryl in the present application.

As used herein, the term "oxyalkylene" refers to divalent moiety -CHX-CHY-0-, where X and Y may be independently selected from hydrogen and C1-C10 alkyl such that the total number of carbon atoms in the oxyalkylene are realized. In a C₄ oxyalkylene, as an example, X may by hydrogen and Y may be C2 alkyl (ethyl), or X any Y may both be Ci alkyl (methyl), together with the two backbone carbon atoms adding up to a total of four carbon atoms.

As used herein, the term "oxyethylene" or ΈΟ" refers to the divalent moiety -CH2-CH2-O-.

Oxyethylene is a C2 oxyalkylene.

As used herein, the term "oxypropylene" or "PO" refers to the divalent moiety -CH(CH3)-CH2-0-, the divalent moiety -CH2-CH(CH3)-0-, or a combination thereof, i.e., if several oxypropylene moieties are comprised in a substituent, both divalent moieties may be present. Oxypropylene is a C3 oxyalkylene.

As used herein, the term "wherein this compound has, on average, 1 to 300 oxyalkylene groups to the molecule. In the present application, one or more oxyethylene groups are also referred to as polyoxyethylene (POE), as polyethylene oxide (PEO), or as polyethylene glycol (PEG), and one or more oxypropylene groups are also referred to as polypropylene oxide (PPO), or as polypropylene glycol (PPG). As an example, component A may thus be described as

Ar-(0-CH2-CH2)r -X, wherein Ar is the optionally substituted aryl or heteroaryl, the PEG is connected to the aryl or heteroaryl via an oxygen atom, X is hydrogen, and r is 1 to 300. As another example, component A may be described as Ar-(0-CH(CH3)-CH2)_r -X, wherein Ar is the optionally substituted aryl or heteroaryl, the PPG is connected to the aryl or heteroaryl via an oxygen atom, X is hydrogen, and r is 1 to 300.

As used herein, the term "the oxyalkylene groups are terminated by

by -SO3M, -OSO3M, -P0₃Mp, -OP0₃Mp" refers to the terminal group of the polyalkyleneglycol. As an example, component B may thus be described as Ar-(0-CH2-CH2)_r -X, wherein Ar is the aryl or heteroaryl, the PEG is connected to the aryl or heteroaryl via an oxygen atom, X is the terminating or end group being -SO3MS (sulfonate), -OSO3MS (sulfate), -ΡΟβΜρ (phosphonate), or -ΟΡΟβΜρ (phosphate), and r is 1 to 300. It is understood that if the polyalkyleneglycol binds to the aryl or heteroaryl via an optional hydroxy or amine substituent, the terminal group may not be -OSO3M, or -OP0₃M_p, but only -SO3M, or -P0₃M_p, as the polyalkyleneglycol is then

"terminated" by an oxygen atom, however, resulting in a group corresponding to -OSO3M_S (sulfate), or -OP0₃M_p (phosphate).

As used herein, the term "C1-C10 alkyl" refers to a straight-chained or branched saturated hydrocarbon group having 1 to 10 carbon atoms, e.g. methyl, ethyl, propyl, 1 -methylethyl, butyl, 1 - methylpropyl, 2-methylpropyl, 1 ,1 -dimethylethyl, pentyl, 1 -methylbutyl, 2-methylbutyl, 3- methylbutyl, 2,2-dimethylpropyl, 1 -ethylpropyl, 1 ,1-dimethylpropyl, 1 ,2-dimethylpropyl, hexyl, 1 - methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1 ,1 -dimethylbutyl, 1 ,2- dimethylbutyl, 1 ,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1 - ethylbutyl, 2-ethylbutyl, 1 ,1 ,2-trimethylpropyl, 1 ,2,2-trimethylpropyl, 1 -ethyl-1 -methylpropyl and 1 -ethyl-2-methylpropyl. In one embodiment, the C1-C10 alkyl is a Ci-C6-alkyl or a Ci-C4-alkyl. A preferred embodiment of a C1-C10 alkyl is a Ci-C4-alkyl. It is understood that the term "C1-C6- alkyl" refers to a straight-chained or branched alkyl group having 1 to 6 carbon atoms. Likewise, the term "Ci-C4-alkyl" refers to a straight-chained or branched alkyl group having 1 to 4 carbon atoms, such as methyl, ethyl, propyl (n-propyl), 1 -methylethyl (iso-propyl), butyl, 1 -methylpropyl (sec. -butyl), 2-methylpropyl (iso-butyl), 1 ,1 -dimethylethyl (tert. -butyl).

As used herein, the term "alkali metal" refers to the alkali metals selected from the group consisting of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and caesium (Cs). In one embodiment, the alkali metal is selected from sodium and potassium.

As used herein, the term "alkaline earth metal" refers to the alkali metals selected from the group consisting of beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba). In one embodiment, the alkali metal is selected from magnesium and calcium.

As used herein, the term "ammonium" refers to the ammonium ion, i.e., Nh .

As used herein, the term "organic ammonium ions" refers to ammonium ions having at least one organic substituent. In one embodiment, the organic ammonium ions have the formula

NH_bR ^a(4-b)⁺, wherein b is an integer selected from 0, 1 , 2, and 3, and R^a is, independently for each occurrence in the ammonium ion, a Ci-Cio-alkyl, (5- to 10-membered)aryl, which aryl may optionally be substituted by 1 to 3 Ci-Cio-alkyl, or C2-C3-hydroxyalkyl (preferably 2-hydroxyethyl or 2-hydroxypropyl). The organic ammonium ion has a single, positive charge.

It is understood that s is selected as 0.5 or 1 , and p is selected as 1 or 2, depending on the charge of the acid group and the metal M, to result in a neutral molecule. Thus, for monovalent cations M, s is 1 and p is 2, respectively, and for divalent cations M, s is 0.5 and p is 1 , respectively. As used herein, the term "naphthol" refers to 1 -hydroxynaphthalene, or 2-hydroxynaphthalene, or a mixture thereof.

As used herein, the term "polyalkyleneglycol" or "poly(alkylene glycol)" refers to poly(Ci-C4-alkyl glycol), poly(Ci-C4-alkyl glycol) mono-alkyl ether, or poly(Ci-C4-alkyl glycol) di-alkyl ether, wherein alkyl is Ci-C6-alkyl, preferably Ci-C4-alkyl. A particularly preferred embodiment of a polyalkyleneglycol is poly(ethylene glycol).

As used herein, the term "poly(ethylene glycol)" refers to poly(ethylene glycol), poly(ethylene glycol) mono-alkyl ether, or poly(ethylene glycol) di-alkyl ether, wherein alkyl is Ci-C6-alkyl, preferably Ci-C4-alkyl. Accordingly, poly(ethylene glycol) has a general formula of

H-(OCH2CH2)x-OH, wherein x is preferably in the range of 1 to 25, more preferably wherein x is in the range of 3 to 22, further preferably wherein x is in the range of 5 to 20; poly(ethylene glycol) mono-alkyl ether has a general formula of (alkyl)-(OCH2CH2)x-OH, wherein x is preferably in the range of 1 to 25, more preferably wherein x is in the range of 3 to 22, further preferably wherein x is in the range of 5 to 20; poly(ethylene glycol) di-alkyl ether has a general formula of (alkyl)-(OCH2CH2)x-0(alkyl), wherein x is preferably in the range of 1 to 25, more preferably wherein x is in the range of 3 to 22, further preferably wherein x is in the range of 5 to 20. A preferred embodiment of a poly(ethylene glycol) mono-alkyl ether is methoxy

poly(ethylene glycol).

As used herein, the term "methoxy poly(ethylene glycol)" refers to poly(ethylene glycol) methyl oxide or poly(ethylene glycol) methyl ether, also termed as "MPEG" or "mPEG", having a general formula of H3C-(OCH2CH2)x-OH, wherein x is preferably in the range of 1 to 25, more preferably wherein x is in the range of 3 to 22, further preferably wherein x is in the range of 5 to 20. In one embodiment, the methoxy poly(ethylene glycol) is MPEG 500 having a number average molecular weight M_n of about 500 g/mol.

As used herein, the term "phenols" refers to benzene being substituted by one or more, such as one, two or three, hydroxy groups, preferably by one hydroxy group.

As used herein, the term "phenol ethers" refers to phenols wherein one or more of the hydroxy groups forms an ether with a Ci-C6-alkyl, preferably Ci-C4-alkyl.

As used herein, the term "naphthols" refers to naphthalene being substituted by one or more, such as one, two or three, hydroxy groups, preferably by one hydroxy group.

As used herein, the term "naphthol ethers" refers to naphthols wherein one or more of the hydroxy groups forms an ether with a Ci-C6-alkyl, preferably Ci-C4-alkyl.

Molecular weight averages (Mz, Mw and Mn), Molecular weight distribution (MWD) and its broadness, described by polydispersity index, PDI= Mw/Mn (wherein Mn is the number average molecular weight and Mw is the weight average molecular weight) may be determined by Size Exclusion Chromatography (SEC) (PEG/PEO calibration, Rl detection, column combination OH- Pak SB-G, OH-20 Pak SB 804 HQ und OH-Pak SB 802.5 HQ from Shodex, Japan; eluent 80 Vol.-% aqueous ammonium formiate solution (0,05 mol/l) und 20 Vol.-% acetonitrile; injection volume 100 μΙ; flow rate 0,5 ml/min). Experimental Part

Examples and Additives not falling under the appendant claims, in particular Examples using such Additives not falling under the appendant claims, not falling under the appendant claims are reference examples and reference Additives. Characterization of raw material bauxite ore

Bauxite grinding experiments of the present application were made with raw bauxite ore.

XRD Analysis

The composition of the bauxite used for the present experiments as determined by XRD (Bruker, D4, Cu Ka) and Rietveld analysis is given in Table 1 .

Table 1 Phase composition of bauxite ore.

Particle size distribution (PDS) of the raw material

The particle size distribution of the bauxite ore as received (the raw ore) was analyzed by dry sieving the raw material over a sieve tower with sieves of different mesh size (Table 2).

Table 2 Particle size distribution of bauxite ore as received.

Bayer liquor

Bauxite slurries for grinding and rheology experiments were performed with (1 ) an artificial Bayer Liquor (ABL) and (2) with spent Bayer liquor (SBL) from an industrial process. The ABL was prepared as a highly alkaline and saline solution of sodium hydroxide and sodium aluminate as follows: 124 g NaOH and 131 g NaAI02 were dissolved in the solvent (H2O) to yield in 1 liter of solution, i.e., per liter of solution.

The composition of the SBL was analyzed with optical emission spectroscopy combined with inductive coupled plasma (ICP-OES), the total organic carbon (TOC) content was measured, and also the dry residue was analyzed with elemental analysis. The results are given in Table 3.

Table 3 Composition of spent Bayer liquor

Slurry preparation and Bauxite grinding

Reference system: ore grinding in planetary ball mill; Particle size investigation

Grinding of bauxite at a concentration of 65 wt.% solid in ABL without additive and with Additive 1 with a dosage of 0.5 wt.%, based on the amount of bauxite, was performed in a planetary ball mill at 400 rpm for 6 minutes with stainless steel balls with a diameter of 2 cm in steel beakers. The particle size distribution was measured in water via static light scattering with a Mastersizer by Malvern. Results are given in Table 4. No significant differences in particle size distribution are found for slurries ground with or without additive for these small particle sizes.

Table 4 Particle size distribution of bauxite ground with and without Additive 1

Rheology measurements of bauxite slurries

Rheology measurements of the ground bauxite slurries were carried out using a plate-plate geometry of 2.5 cm diameter with a slit height of 1 mm and by applying a shear rate ramp of from 0.01 up to 500 1/s (Anton Paar MCR 301 Rheometer). The dosages of additives are given in wt.-% with respect to bauxite solid content. To account for addition of water by aqueous polymer solution addition, reference samples were prepared, adding the same amount of water which would be introduced by polymer solutions to estimate the influence of water addition. These are called "Blank". In SBL-based slurries, if no water was added to account for the water added by dosing the additive, but only SBL (to reach the same bauxite weight content level), the sample is called "Reference". The Blank or Reference gives the reference value in relation to the respective sample, stemming from one milling batch split into 50 g aliquots, if not stated otherwise, since samples from one batch can be compared more reliably.

With respect to the Blank and Reference values given in the tables below, it may be added that Blanks and References were prepared from different batches, and there are always some minor differences in solid content, such as due to non-grindable coarse particles. A comparison should thus be based on the values within one table (stemming from the same milling batch), and not between different tables. The results are given as the mean value of aliquots from different milling batches each for the comparison (number of batches indicated in the table), or as a single measurement value.

Example 1a: Rheology of different additives with ABL - Additive addition after grinding

Artificial Bayer liquor and bauxite were ground in a planetary ball mill for 6 minutes at 400 rpm. Afterwards, from one milling batch, the slurry was split into 50 g aliquots since samples from one batch can be compared more reliably. To these aliquots of the slurry, 0.5 wt.-%, based on the amount of bauxite, of Additive 1 (added as a 25 wt.-% aqueous solution), or the respective amount of deionized water (called "Blank"), were added (yielding a 65 wt.-% solid bauxite content) and mixed for 5 minutes before rheological properties were measured. Results at a shear rate of 500 1/s are given in Table 5, rheological curves are given in Figure 1 .

Table 5 Rheological measurements with Additive 1 and ABL, added after grinding

The same process was repeated for another batch using Additive 3 instead of Additive 1 (Figure 2 and Table 6), however, only with one aliquot. Table 6 Rheological measurements with Additive 3 and ABL, added after grinding

Example 1b: Rheology of Additive 1 with SBL - Additive addition after grinding

Spent Bayer liquor and bauxite were ground in a planetary ball mill for 6 minutes at 400 rpm. Afterwards, from one milling batch, the slurry was split into 50 g aliquots since samples from one batch can be compared more reliably. To these aliquots of the slurry, 0.5 wt.-%, based on the amount of bauxite, of Additive 1 (added as a 25 wt.-% aqueous solution), the respective amount of deionized water (called "Blank") or the respective amount of SBL (called

"Reference"), were added (yielding a 65 wt.-% solid bauxite content) and mixed for 5 minutes before rheological properties were measured. Results at a shear rate of 500 1/s are given in Table 7, rheological curves are given in Figure 3 and Figure 4. It is understood that a comparison should only be made between experiments based on the same batch of slurry, i.e., between the first two lines and the last two lines of Table 7.

Table 7 Rheological measurements with Additive 1 and SBL, added after grinding

Example 2a: Rheology of Additive 2 with ABL - Additive addition after grinding

Artificial Bayer liquor and bauxite were ground in a planetary ball mill for 6 minutes at 400 rpm. Afterwards, from one milling batch, the slurry was split into 50 g aliquots since samples from one batch can be compared more reliably. To these aliquots of the slurry, 0.5 wt.-%, based on the amount of bauxite, of Additive 2 (added as a 25 wt.-% aqueous solution), or the respective amount of deionized water (called "Blank"), were added (yielding a 65 wt.-% solid bauxite content) and mixed for 5 minutes before rheological properties were measured. Results at a shear rate of 500 1/s are given in Table 8, rheological curves are given in Figure 5. Table 8 Rheological measurements with Additive 2 and ABL, added after grinding

Example 2b: Rheology of different additives with SBL - Additive addition after grinding

Spent Bayer liquor and bauxite were ground in a planetary ball mill for 6 minutes at 400 rpm. Afterwards, from one milling batch, the slurry was split into 50 g aliquots since samples from one batch can be compared more reliably. To these aliquots of the slurry, 0.5 wt.-%, based on the amount of bauxite, of Additive 4, 5 or 6, respectively, (added as a 25 wt.-% aqueous solution), the respective amount of deionized water (called "Blank") or the respective amount of SBL (called "Reference"), were added (yielding a 65 wt.-% solid bauxite content) and mixed for 5 minutes before rheological properties were measured. Results are given at a shear rate of 500 1/s.

This process was performed for different batches of slurries using Additive 4 (Figure 6 and Table 9; Figure 7 and Table 10), Additive 5, or Additive 6 (Figure 8 and Table 1 1 ), respectively.

Table 9 Rheological measurements with Additive 4 and SBL, added after grinding

Sample Additive Liquid Shear stress Shear stress reduction

dosage at 500 1/s [Pa] mean at 500 1/s as

[wt%] compared to the

reference [%]

Blank 2 water SBL 903±44 - (mean of 6)

Additive 4 0.5 SBL 691 ±27 23

(mean of 4)

Table 10 Rheological measurements with Additive 4 and SBL, added after grinding

Sample Additive Liquid Shear stress Shear stress reduction

dosage at 500 1/s [Pa] mean at 500 1/s as

[wt%] compared to the

reference [%]

Reference 1 SBL SBL 890 -

Additive 4 0.5 SBL 666 25 Table 1 1 Rheological measurements with Additives 5 and 6 and SBL, added after grinding

Example 3: Rheology at different solid contents using Additive 1

"Reference"), were added (yielding solid bauxite contents between 55 and 70 wt.-%) and mixed for 5 minutes before rheological properties were measured. Results at a shear rate of 53 and 500 1/s are given in Table 12.

With Additive 1 the shear stress at 53 1/s can be reduced by (60±7) % as compared to the reference at different solid contents. Thus, with Additive 1 at 0.5 wt.-% dosage with respect to bauxite, the solid content can be increased by about 5 wt.-% without increasing shear stress (see also Figure 9).

Example 4: Rheology at different solid contents using Additive 2

Spent Bayer liquor and bauxite were ground in a planetary ball mill for 6 minutes at 400 rpm. Afterwards, from one milling batch, the slurry was split into 50 g aliquots since samples from one batch can be compared more reliably. To these aliquots of the slurry, 0.5 wt.-%, based on the amount of bauxite, of Additive 2 (added as a 25 wt.-% aqueous solution), the respective amount of deionized water (called "Blank") or the respective amount of SBL (called

"Reference"), were added (yielding solid bauxite contents between 55 and 70 wt.-%) and mixed for 5 minutes before rheological properties were measured. Results at a shear rate of 53 and 500 1/s are given in 0.

With Additive 2 the shear stress at 53 1/s can be reduced by (33±10) % as compared to the reference at different solid contents. Thus, with Additive 2 at 0.5 wt.-% dosage with respect to bauxite, the solid content can be increased by about 2.5 wt.-% without increasing shear stress (see also Figure 10). Table 12 Rheological properties of Bayer slurry as a function of solid content and shear stress reduction with Additive 1

Table 13 Rheological properties of Bayer slurry as a function of solid content and shear stress reduction with Additive 2

Example 5: Rheology at different temperatures with Additive 1 and SBL

"Reference"), were added (yielding a 65 wt.-% solid bauxite content) and mixed for 5 minutes before rheological properties were measured. Slurries were measured in plate-plate geometry in a humidity chamber to avoid evaporation of water during heating and equilibration.

Measurements were performed at a shear rate of 200 1/s for 20 sec. Results are given in Table 14.

Table 14 Rheological properties with Additive 1 and SBL as a function of temperature

Example 6: Dose efficiency of Additive 1 in SBL

Spent Bayer liquor and bauxite were ground in a planetary ball mill for 6 minutes at 400 rpm. Afterwards, from one milling batch, the slurry was split into 50 g aliquots since samples from one batch can be compared more reliably. To these aliquots of the slurry, different amounts (0.015, 0.05, 0.5 wt.-%, based on the amount of bauxite) of Additive 1 (added as a 25 wt.-% aqueous solution), the respective amount of deionized water (called "Blank") or the respective amount of SBL (called "Reference"), were added (yielding a 65 wt.-% solid bauxite content) and mixed for 5 minutes before rheological properties were measured. Slurries were measured in plate-plate geometry. Results at a shear rate of 500 1/s are given in Table 15. Table 15 Dose efficiency of Additive 1 with SBL

Example 7: Dose efficiency of Additive 3 in ABL

Artificial Bayer liquor and bauxite were ground in a planetary ball mill for 6 minutes at 400 rpm. Afterwards, from one milling batch, the slurry was split into 50 g aliquots since samples from one batch can be compared more reliably. To these aliquots of the slurry, different amounts (wt.-% as indicated in Table 16 below, based on the amount of bauxite) of Additive 3 (added as a 25 wt.-% aqueous solution) were added (yielding a 65 wt.-% solid bauxite content) and mixed for 5 minutes before rheological properties were measured. Slurries were measured in plate- plate geometry. Results at a shear rate of 500 1/s are given in Table 16.

Table 16 Dose efficiency of Additive 3 with ABL

Additive Viscosity Viscosity reduction at

Sample Additive dosage Liquid at 500 1/s 500 1/s as compared

[wt.-%] [mPas] to Reference 1 [%]

Blank 1 water ABL 616 -

Additive 3

Additive 3 0.15 ABL 529 14

and water

Additive 3

Additive 3 0.37 ABL 465 25

and water

Additive 3

Additive 3 0.74 ABL 365 41

and water

Additive 3

Additive 3 1 .48 ABL 314 49

and water

Additive 3

Additive 3 2.22 ABL 298 52

and water

Additive 3 Additive 3 2.96 ABL 299 51 Example 8: Dose efficiency of Additives 4 and 5 in SBL

Spent Bayer liquor and bauxite were ground in a planetary ball mill for 6 minutes at 400 rpm. Afterwards, from one milling batch, the slurry was split into 50 g aliquots since samples from one batch can be compared more reliably. To these aliquots of the slurry, different amounts (0.015, 0.05, 0.5 wt.%, based on the amount of bauxite) of the indicated Additive (added as a 25 wt.-% aqueous solution), the respective amount of deionized water (called "Blank") or the respective amount of SBL (called "Reference"), were added (yielding a 65 wt.-% solid bauxite content) and mixed for 5 minutes before rheological properties were measured. Slurries were measured in plate-plate geometry. Results at a shear rate of 500 1/s are given in Table 17. Table 17 Dose efficiency of additives in Bayer slurry with spent Bayer liquor.

Example 9: Formulations with MPEG 500 and Additives 1 and 3 in ABL

Artificial Bayer liquor and bauxite were ground in a planetary ball mill for 6 minutes at 400 rpm. Afterwards, from one milling batch, the slurry was split into 50 g aliquots since samples from one batch can be compared more reliably. To these aliquots of the slurry, 0.5 wt.-%, based on the amount of bauxite, of Additive 1 or 3 (added as a 25 wt.-% aqueous solution), or the respective amount of deionized water (called "Blank"), were added (yielding a 65 wt.-% solid bauxite content) and mixed for 5 minutes before rheological properties were measured. When MPEG was added, an additive formulation was prepared containing the additive and the given amount of MPEG (in wt.-%, based on the amount of additive). A 25 wt.-% aqueous solution was prepared from the additive formulation, which solution was then added. Results at a shear rate of 500 1/s are given in Table 18. Table 18 Rheological properties with formulations of Additives 1 and 3 with MPEG 500

Energy Efficiency and Rheology experiments with bauxite ground in a big ball mill at the conditions close to industrial

These experiments aim to determine the effect of each chemical additive in the performance of the grinding process. The ore samples were ground at different dosages of each additive, and the resulting viscosity and particle size distribution are measured in every step. For grinding the samples, a 2 L stainless-steel laboratory scale ball mill was used, filled with a suitable ball string calculated to produce the maximum efficiency given the particle size distribution of the feed sample. This method is scalable to real plant conditions, since the main controlling variable of the mill's grinding energy efficiency is the Specific Surface Area a (m² of ball surface/m³ balls) exposed by the ball charge for impact and abrasion of the ore particles, regardless of the actual combination of sizes that make up the 'string' of balls in the charge (Sepulveda, J.E. (2007). SPEC - a pseudo-empirical correlation for the assessment of the ideal ball size for conventional and sag milling applications. Proceedings Workshop SAG2007 Conference. Vina del Mar, Chile). The main variables during grinding were: mill volume, V = 2 L; load volume, J = 33 %; speed, N=75 % of critical (91 rpm); interstitial powder filling, U = 0.6; sample size, W = 150 g; solids content in Bayer slurry = 65% w/w; grinding time, t = 8 min, equivalent to specific energy consumption, E = 5 kWh/t for all cases. In all experiments, the liquid phase is spent Bayer liquor (SBL). The liquid part of all the polymer solutions is double- distilled water.

With the bauxite ore samples, product size distributions were determined after batch grinding tests. Since the characteristic values of the feed and product sizes (F80 and P80) and the specific energy consumption (E = 5 kWh/t) are known in each case, the energy required to perform the comminution task of converting a given mass of ore from a particular F80 to P80, is defined as (F.C. Bond, "Testing and Calculations" Ch.5, Section 3A, SME Mineral Processing Handbook, N.L. Weiss editor, (1985), p 3A-18):

_E_

Op. Work Index (OWi) = 10

(I/VPSO - I/VFSO)

Figure 1 1 represents the particle size distribution of Bayer slurry before milling.

Figure 12 represents the particle size distributions of Bayer slurry after milling using the batch mill for the cases without and with 500 g/Ton of Additive 1 in spent Bayer Liquor in identical milling conditions. Tests 2 and 3 are identical test made to show reproducibility.

Table 19 summarizes the calculation and comparison of resulting operational work indexes values (OWi) obtained using the batch mill for both without and with 500 g/Ton of Additive 1 .

Table 19 Summary of batch grinding test results with Additive 1 at the dosage 500 g/ton

Synthesis of additives

Synthesis of Additive 1

Phenoxyethanol (124.31 g) was placed into 1 L double wall heatable glass reactor equipped with reflux condenser and mechanical stirrer, followed by slow addition of polyphosphoric acid (1 15 % based on H3PO4, 67.50 g) through a drop funnel (about 10-15 Min, the temperature was controlled not to exceed 40 °C). The resulting mixture was heated to 100 °C and kept at this temperature over 1 h. Then 100 % methanesulfonic acid (Lutropur^® MSA of BASF, 31 .79 g) was added to the reaction mixture, followed by the addition of 30 % aqueous formaldehyde solution (85.8 g) via syringe pump over about 80 min, keeping the reaction temperature above 97 °C. The resulting polymer solution was further heated for 24 min, and then MPEG 500 (49.95 g) was added to stop the polycondensation, followed by addition of cold water (559.16 g) and 50 % aqueous NaOH solution for the neutralization to pH of 6.5.

The molecular weight of the resulting polymer was analyzed by SEC (PEG/PEO calibration, Rl detection, column combination OH-Pak SB-G, OH-20 Pak SB 804 HQ und OH-Pak SB 802.5 HQ from Shodex, Japan; eluent 80 Vol.-% aqueous ammonium formiate solution (0,05 mol/l) und 20 Vol.-% acetonitrile; injection volume 100 μΙ; flow rate 0,5 ml/min).

SEC-data: Mw = 9,8 kDa, Mn = 6,4 kDa, PDI = 1 ,52. (MPEG 500 peak is well separated from the polymer peak).

Synthesis of Additive 3

Phenoxyethanol (75.99 g) was placed into a 1 L heatable glass reactor equipped with reflux condenser and mechanical stirrer, followed by slow addition of polyphosphoric acid (1 15 % based on H3PO4, 54.96 g) through a drop funnel over 100 min (the temperature was maintained below 40 °C). The resulting mixture was heated to 95 °C and kept at this temperature for 1 h. Then, polyethyleneglycol phenyl ether ("Pluriol A 750 PH", Mw = 750 g/mol, 1 12.50 g) and paraformaldehyde (24.89 g) were added to the reaction mixture, followed by the addition of 70 % methanesulfonic acid (Lutropur^® MSA of BASF, 28.83 g) over 30 min via syringe pump, and keeping the reaction temperature above 97 °C. The resulting polymer solution was further heated for 3 h at about 100 °C Then, water (300 g) was added, followed by reflux over 30 min. After cooling to 60 °C, the polymer solution was neutralized by 50 % aqueous NaOH solution to a pH of 6.5.

The molecular weight of the polymer was analyzed with SEC (details see above at Additive 1 ). SEC-data: Mw = 14,4 kDa, Mn = 7,7 kDa, PDI = 1 ,77. Synthesis of Additive 2

Water (40 g) was placed into a heatable double wall reaction vessel equipped with reflux condenser, thermometer and pH-meter. 30 wt-% aqueous formaldehyde solution (1 .28 mol) was mixed with sodium sulfite (0.27 mol) and cyclohexanone (0.61 mol) and added to the water. The pH was adjusted with 50 wt-% aqueous sodium hydroxide (NaOH) solution to a pH of 13.5. The viscous mixture was heated to reflux for 3 hours. After cooling to room temperature, formic acid was used to adjust the pH to 10. The molecular weight of the polymer was analyzed with SEC (the method details see in the synthetic procedure for Additive 1 ) and viscosimetry.

SEC-data: Mw = 28.6 kDa, Mn = 20.8, PDI = 1.38. Synthesis of Additive 4

In the same manner as for Additive 2 above, Additive 4 was prepared by using 0.56 mol cyclohexanone instead of 0.61 mol, and KOH for pH adjustment instead of NaOH.

SEC-data: Mw = 32.7 kDa; Mn = 19.7 kDa; PDI = 1.66. Synthesis of Additive 5

Calcium salt of naphthalene sulfonate-formaldehyde condensate was prepared according to well-known conventional synthetic procedures described for example in BASF patent DE292531 (1913) and in Yan et al., "Synthesis, Separation and adsorption of naphthalene sulphonate formaldehyde condensates", Tenside Surf. Det. 42 (2005), 102-105. As a base for

neutralization, calcium hydroxide was used. The molecular weight of the polymer was analyzed with SEC (the method details see in the synthetic procedure for Additive 1 ):

several polymer and oligomer peaks:

1 ) Mw = 12,6 kDa, Mn = 9,4 kDa, PDI = 1 ,33;

2) Mw = 2,2 kDa, Mn = 2,0 kDa, PDI = 1 ,08;

3) Mw = 0,87 kDa, Mn = 0,82 kDa, PDI = 1 ,06.

Synthesis of Additive 6

Sodium salt of naphthalene sulfonate-formaldehyde condensate was prepared according to well-known conventional synthetic procedures described for example in BASF patent DE292531 (1913) and in Yan et al., "Synthesis, Separation and adsorption of naphthalene sulphonate formaldehyde condensates", Tenside Surf. Det. 42 (2005), 102-105. The molecular weight of the polymer was analyzed with SEC (the method details see in the synthetic procedure for Additive 1 ): several polymer and oligomer peaks

1 ) Mw = 9,8 kDa, Mn = 8,5 kDa, PDI = 1 ,15;

2) Mw = 2,2 kDa, Mn = 2,1 kDa, PDI = 1 ,06;

3) Mw = 0,95 kDa, Mn = 0,91 kDa, PDI = 1 ,04.

Claims

C L A I M S

1 . Use of a polycondensate as grinding aid for ores and minerals,

wherein the polycondensate is a monomer-based condensation product comprising at least:

B) an optionally substituted 5- to 10-membered aromatic or heteroaromatic compound, wherein this compound has, on average, 1 to 300 C2-C20 oxyalkylene groups, which groups are connected to the aromatic or heteroaromatic compound via an oxygen (O) or nitrogen (N) atom, and wherein the oxyethylene and/or oxypropylene groups are terminated by -S0₃M_s, -OS0₃M_s, -P0₃M_p, or -OP0₃M_p, wherein M is selected from the group consisting of hydrogen, alkali metals, alkaline earth metals, ammonium and organic ammonium ions, s may be 0.5, or 1 , and p may be 1 or 2; and

C) an aldehyde or an aldehyde source; as well as

2. The use of claim 1 , wherein the aromatic or heteroaromatic compound of component A comprises at least one substituent selected from the group consisting of OH, OR¹, NH2, NHR¹, NR¹2, and C1-C10 alkyl, wherein the C1-C10 alkyl may optionally be substituted by phenyl and/or 4-hydroxy phenyl, and R¹ is a C1-C4 alkyl.

3. The use of any one of claims 1 to 2, wherein the aromatic or heteroaromatic compound of component A and/or B is, independently, a phenol derivative, a naphthol derivative, an aniline derivative, or a furfuryl alcohol derivative, or is derived from a compound selected from the group consisting of phenol, cresol, resorcinol, nonylphenol, methoxyphenol, naphthol, methylnaphthol, butylnaphthol, bisphenol A, aniline, methylaniline,

hydroxyaniline, methoxyaniline, furfuryl alcohol and salicylic acid, and preferably wherein the aromatic or heteroaromatic compound of components A and B are identical.

4. The use of any one of claims 1 to 3, wherein the compound of component A and/or the compound of component B has, on average, 1 to 20 oxyalkylene groups per molecule, preferably 1 to 15 oxyalkylene groups per molecule, and/or

wherein the oxyalkylene groups are C2-C10 oxyalkylene units, preferably C2-C5 oxyalkylene units, more preferably C2-C4 oxyalkylene units, and even more preferably C2-C₃ oxyalkylene units.

5. The use of any one of claims 1 to 4, wherein the aromatic compound of component D comprises at least one substituent selected from the group consisting of OH, NH2, OR², NHR2, NR²2, COOH, C1-C4 alkyl, S0₃H, OSO3H, PO3H2, and OPO3H2, wherein the C1-C4 alkyl may be optionally substituted by phenyl and/or 4-hydroxy phenyl, and R² is a C1-C4 alkyl which may be optionally substituted by a substituent selected from the group consisting of OH, COOH, OSO3H, S0₃H, PO3H2, and OPO3H2.

6. The use of any one of claims 1 to 5, wherein the aromatic compound of component D is a compound selected from the group consisting of phenol, phenoxyacetic acid, phenoxyethanol, phenoxyethanol phosphate, phenoxydiglycol, phenoxy(poly)ethylene glycol phosphate, methoxyphenol, resorcinol, cresol, bisphenol A, nonylphenol, aniline, methylaniline, N-phenyldiethanolamine, N-phenyl-N,N-dipropanoic acid, N-phenyl-N,N- diacetic acid, N-phenyldiethanolamine diphosphate, phenolsulphonic acid, anthranilic acid, succinic monoamide, furfuryl alcohol, melamine, and urea.

7. The use of any one of claims 1 to 6, wherein the aldehyde of component C is selected from the group consisting of formaldehyde, paraformaldehyde, acetaldehyde, paraldehyde, 1 ,3,5-trioxane, glyoxylic acid, furfurylaldehyde, benzaldehyde,

benzaldehydesulphonic acid and benzaldehydedisulphonic acid, preferably wherein component C is formaldehyde or paraformaldehyde, further preferably formaldehyde.

8. The use of any one of claims 1 to 7, wherein the molar ratio of (component C) :

(component A, component B and optionally component D) is 1 : 0.5 to 1 : 2, and preferably 1 : 0.9 to 1 : 1.1 .

9. The use of any one of claims 1 to 8, wherein the molar ratio of components A : B is from 10 : 1 to 1 : 10, preferably from 1 :1 to 1 :5.

10. The use of any one of claims 1 to 8, wherein component D is present, and the molar ratio of components A : D is from 10 : 1 to 1 : 10.

1 1 . The use of any one of claims 1 to 10, wherein the polycondensate is used in

combination with at least one poly(ethylene glycol), preferably poly(ethylene glycol) methyl ether, further preferably wherein the poly(ethylene glycol) methyl ether has a Mn of about 500 g/mol.

12. The use of claim 12, wherein the poly(ethylene glycol) is used in an amount of from 10 to 50 % by wt., preferably 20 to 40 % by wt., based on the total amount of polycondensate.

13. The use of any one of claims 1 to 12, wherein the polycondensate is used as grinding aid in an aqueous suspension or aqueous slurry of an ore and/or mineral.

14. The use of claim 13, wherein the polycondensate is used in the aqueous suspension or aqueous slurry in an amount of from 0.001 % to 5 % by wt., preferably of from 0.01 % to 0.5 % by wt., based on the total amount of ore or mineral.

15. The use of any one of claims 1 to 14, wherein the ore or mineral is selected from the group of an Al containing ore or mineral, a Fe containing ore or mineral, a Cu containing ore or mineral, a Mo containing ore or mineral, an Au containing ore or mineral, or mixtures thereof, and preferably wherein the ore or mineral is an Al containing ore or mineral, preferably wherein the polycondensate is used as grinding aid to improve the grinding of a bauxite containing slurry during the grinding stage of an alumina extraction process, preferably wherein said alumina extraction process is a Bayer process.