CA2083818A1 - Process for the recovery of minerals from non-sulfidic ores by flotation - Google Patents

Abstract

Abstract A process for the recovery of minerals from non-sulfidic ores by flotation Esters of dicarboxylic acids with fatty acid mono-alkanolamides, optionally in admixture with other anionic or nonionic surfactants, are suitable as collectors for the flotation of non-sulfidic ores, more particularly apatite.

Description

HENKEL KGaA ~ 8 Dr. Fb/28 22nd May, 1990 Patent Application Proce~ for the recovery o~ mineral~ from non-qulfidic ores bY flotation This invention relates to a process for the recovery of minerals from non-sulfidic ores by flotation, in which esters of dicarboxylic acids with fatty acid monoal~anol-amides, optionally in admixture with other anionic or nonionic surfactants, are used as collectors.
Flotation is a separation technique commonly used in the dressing of mineral ores for separating valuable minerals from the gangue. For flotation, the ore is sub-jected to preliminary size-reduction, dry-ground, but pref-- 10 erably wet-ground and suspended in water. A collector is then added, often in conjunction with other reagents, in cluding frothers, regulators, depressors, (deactivators) and/or activators, in order to facilitate separation of the valuable minerals from the unwanted gangue constituents of the ore in the subsequent flotation process. These re-agents are normally allowed to act on the finely ground ore for a certain time (conditioning) before air is blown into the suspension to produce a foam at its surface and to start the flotation process. The collector acts as a hydrophobicizing agent on the surface of the minerals, causing the minerals to adhere to the gas bubbles formed durinq the aeration step. The mineral constituents are selectively hydrophobicized so that the unwanted constitu-ents of the ore do not adhere to the gas bubbles and remain behind while the mineral-containing foam is stripped off and further processed. The object of flotation is to D 9130 2 2~
recover the valuable mineral of the ores in as high a yield as possible while at the same time obtaining high enrich-ment of the valuable mineral.
Anionic or cationic surfactants are mainly used as collectors in the flotation of non-sulfidic ores. Their function is to adsorb selectively on the surface of the valuable minerals to ensure high enrichment in the flota-tion concentrate. In addition, the collectors are intended to develop a stable, but not excessively stable flotation lo foam.
In many cases, however, the collectors frequently used in the flotation of non-sulfidic ores, such as for example fatty acids or alkyl sulfosuccinates tAufbere~tungstec~ni~, 26, 632 ~1985)~, lead to unsatisfactory recovery of the valuable minerals when used in economically reasonable quantities.
Accordingly, the problem addressed by the present invention was to provide collectors having improved proper-ties to make the flotation process more economical.
The present invention relates to a process for the recovery of minerals from non-sulfidic ores by flotation, in which ground ore is mixed with water to form a suspen-sion, air is introduced into the suspension in the presence oS a collector system and the foam formed is stripped off together with the floated solids present therein and in which esters of dicarboxylic acids with fatty acid mono-alXanolamides corresponding to one of formulae ($) to (VI) below Rl-CO-NH-C~2-C~R2-O-CO-~CH2),-COOX tI) Rl-CO-NH-CH2-C~R2-O-CO-CH=CH-COOX ~II) D 913 0 3 ~,~ 8 Rl-C0~ CH2-CaR2-0-CO-C~_.C-COOX ~III) Rl-CO-NX-CHz-CHR2-O-CO-7=CH-COOX ~ IV) c~3 Rl--CO-N~-ClIz-CH~2-O-CO-C}12-C-COOX ~V) Rl--CO~ C~I2-CNR2-O-CO-C-CH2-COOX ~VI ) Il in which Rl-Co is an acyl radical containing 6 to 22 carbon atoms and 0, 1, 2 or 3 double bonds, R2 is hydrogen or a methyl group, m is a number of 1 to 10 and X is hydrogen, an alkali metal or an ammonium ion, are used as collectors.
In the context of the invention, non-sulfidic ores are understood to be salt-type minerals, for example fluorite, scheelite, baryta, apatite, iron oxides and other metal oxides, for example the oxides of titanium and zirconium, and also certain silicates and alumosilicates.
The esters of dicarboxylic acids with fatty acid mono-alkanolamides are known substances which may be produced by the relevant methods of organic synthesis. One suitable method for their production comprises, for example, react-ing dicarboxylic acids, dicarboxylic acid monoesters or di-carboxylic anhydrides with fatty acid monoalkanolamides.
The production of the esters t S also described in GB
61S,66S, CH 2~8 209, C~ 256 76~ and D~-A-3S 06 838.
Malonic acid, fumaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid or dodecanedioic acid are suitable dicarboxylic acid compo-nents for the production of the esters used in the process D 9130 4 ~ ~ 5~ 8 according to the invention. Esters distinguished by par-ticularly advantageous properties in the process according to the invention are obtained on the basis of maleic acid, succinic acid, glutaric acid, adipic acid, citraconic acid or itaconic acid and mixtures of these acids with one another.
The amide component may be selected from fatty acid monoalkanolamides corresponding to formula (VII) Rl--CO-NH-CR2-CH22-OH ~VII) in which R1-CO and R2 are as defined above. The acyl group R1-CO may be derived, for example, from caproic acid, capry-lic acid, capric acid, lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, elaidic acid, petroselic acid, linoleic acid, linolenic acid, gado-leic acid, arachidonic acid, behenic acid or erucic acid.
As usual in oleochemistry, the fatty acids on which the fatty acid alkanolamides are based may also be present in the form of technical mixtures of the type obtained, for example, in the pressure hydrogenation of natural fats and oils, for example coconut oil, palm oil, palm kernel oil, rapeseed oil, sunflower oil or beef tallow. By contrast, the alkanolamine group is derived from monoethanol-1,2-amine or monopropanol-1,2-amine. Esters distinguished by particularly advantageous properties in the process accord-ing to the invention are obtained on the basis of fatty acid moncalXanolamides in which Rl-CO represents acyl radi-cals containing 12 to 18 carbon atoms or 0 or l double bond and RZ is hydrogen.
The process according to the invention enables the esters of dicarboxylic acids with fatty acid monoalkanol-amides to be used as collectors for the recovery of miner-als from non-sulfidic ores by flotation either on their own or in the presence of other anionic or nonionic surfac-D 9130 5 2~
tants.
In the context of the invention, anionic surfactants are fatty acids, alkyl sulfates, alkyl ether sulfates, al-kyl sulfosuccinates, alkyl sulfosuccinamates, alkyl benzene sulfonates, alkyl sulfonates, petrol sulfonates, acyl lact-ylates, sarcosides, alkyl phosphates and alkyl ether phos-phates. All these anionic surfactants are known compounds of which the production - unless otherwise stated - is de-scribed, for example, in J. Falb-, ~. Ha~serodt ted.), "~atalysatoren, ~onside un~ Mi~er~lol~d~itive", Thiems Verlag, 8tuttgart, 197~ or J. Falb- (ed.) "8urfactant~ in Con~umer Pro~ucts~, 8pringer Verl~g, Berlin, 1986.
Suitable fatty acids are, above all, the linear fatty acids corresponding to formula (VIII) R3-Cooy (VIII) in which R3 is an aliphatic hydrocarbon radical containing 12 to 18 carbon atoms and 0, 1, 2 or 3 double bonds and Y
is an alkali metal, alkaline earth metal or ammonium ion, which are obtained from vegetable or animal fats and oils, for example by lipolysis and optionally fractionation and/
or separation by the rolling-up process. Particular signi-ficance is attributed in this regard to the sodium and potassium salts of oleic acid and tall oil fatty acid.
Suitable alkYl sulfates are the water-soluble salts of sulfuric acid semiesters of fatty alcohols corresponding to formula ~
R~-O-8O3Z (IZ) in which R~ is a linear or branched alkyl radical containing 8 to 22 and preferably 12 to 18 carbon atoms and Z is an alkali metal or ammonium ion.
Suitable alkYl ether sulfate~ are the water-soluble D 9130 6 Z~ 18 salts of sulfuric acid semiesters of fatty alcohol polygly-col ethers corresponding to formula ~) R -~OC~2CH~O~O3Z ~X) R~

in which R5 is a linear or branched alkyl radical containing 8 to 22 and preferably 12 to 18 carbon atoms, R5 is hydrogen or a methyl group, n is a number of 1 to 30 and preferably 2 to 15 and Z is as defined above.
Suitable 31~Yl sulfosuccinates are sulfosuccinic acid monoesters of fatty alcohols corresponding to formula ~XI) R7-ooC-C~2-CR-Cooz ~XI) in which R7 is a linear or branched alkyl radical contain-ing 8 to 22 and preferably 12 to 18 carbon atoms and Z is as defined above.
Suitable alkyl sulfosuccinamates are sulfosuccinic acid monoamides of fatty amines corresponding to formula R8-NH-OC-CR2-CR-COOZ ~XII) ~o3~

in which R8 is a linear or branched alXyl radical contain-ing 8 to 22 and preferably 12 to 18 carbon atoms and Z is as defined above.
Suitable alkyl benzene sulfonates are compounds corre-sponding to formula ~XITT) R~-Cd~-8O3~ (XIII) in which R9 is a linear or branched alkyl radical containing 4 to 16 and preferably 8 to 12 carbon atoms and Z is as defined above.
Suitable alkvl sulfonates are compounds corresponding to ~XIV) R1-80~Z ~XIV) in which R10 is a linear or branchad alkyl radical contain-ing 12 to 18 carbon atoms and Z is as defined above.
Suitable Detrol sulfonates are compounds obtained by reaction of lubricating oil fractions with sulfur trioxide or oleum and subsequent neutralization with sodium hydrox-ide. Particularly suitable petrol sulfonates are products in which the hydrocarbon radicals predominantly have chain lengths of 8 to 22 carbon atoms.
Suitable acvl lactvlates are compounds corresponding to formula ~V) Rll-CO-O-C~-COOZ ~gV) I

in which R~1 is an aliphatic, cycloaliphatic or alicyclic, optionally hydroxyl-substituted hydrocarbon radical con-taining 7 to 23 carbon atoms and 0, 1, 2 or 3 double bonds and Z is as defined above. The production and use of acyl lactylates in flotation is described in DE-A-32 38 060.
Suitable sarcosides are substances corresponding to formula ~XVI) Rl2-CO-N-C~2-COOH ~ XYI: ) ~ 3~

in which R~2 i9 an aliphatic hydrocarbon radical containing 12 to 22 carbon atoms and 0, 1, 2 or 3 double bonds.
Suitable alkyl ~hosphates and alkyl ether phosphates are compounds corresponding to formulae ~XVII) and ~XVIII), Rl3- ~OCH2CH2) pO O
p ~YVII) 10 R~ OClI2CH2) qO 02 and Rl3-~ocH2cH2~po O ~XVIII) \
/ \
ZO OZ

in which R~3 and Rl~ independently of one another represent an alkyl or alkenyl radical containing 8 to 22 carbon atoms and p and q are 0 in the case of the alkyl phosphates and a number of 1 to 15 in the case of the alkyl ether phos-phates and Z is as defined above.
If the dicarboxylic acid N-alkyl monoamides are used in admixture with alkyl phosphates or alkyl ether phos-phates, the phosphates may be present in the form of mono-or diphosphates. In this case, mixtures of mono- and di-alkyl phosphates of the type obtained in the industrial production of such compounds are preferably used.
In the context of the invention, nonionic surfactants are understood to be fatty alcohol polyglycol ethers, alkyl phenol polyglycol ethers, fatty acid polyglycol esters, ; fatty acid amide polyglycol ethers, fatty amine polyglycol ethers, mixed ethers, hydroxy mixed ethers and alkyl glyco-sides. All these nonionic surfactants are known compounds of which the production - unless otherwise stated - is described in J. Falbe, U. Hasserodt (ed.), "Katalysatoren, i :., s~

Tenside und Mineraloladditive", Thieme Verlag, Stuttgart, 1978 or J. Falbe ~ed.) "Surfactants in Consumer Products", Springer Verlag, Berlin, 1986.
Suitable fatty alcohol ~olvqlycol ethers are adducts of on average n mol ethylene and/or propylene oxide with fatty alcohols corresponding to formula ~XIX) R~5~oc~2lCH~ DO~ (~IX~
1 0 }~,6 in which Rl5 is a linear or branched alkyl radical contain-ing 8 to 22 and preferably 12 to 18 carbon atoms, R6 is hydrogen or a methyl group and n i5 a number of 1 to 30 and preferably a number of 2 to 15.
Suitable alkvl Dhenol ~olvalvcol ethers are adducts of on average n mol ethylene and/or propylene glycol with alkyl phenols corresponding to formula (XX) Rl6-C6H~-(OC~2C~)DOH (XX) a6 in which R16 is an alkyl radical containing 4 to 15 and preferably 8 to 10 carbon atoms and R6 and n are as defined above.
Suitable fattv 3~ polyqlvcol esters are adducts of on average n mol ethylene and/or propylene oxide with fatty alcohols corresponding to formula (XXI) R17-Co ( OC~2CII ) DO~I (XXI) ~,6 in which Rl7 is an aliphatic hydrocarbon radical containing 5 to 21 carbon atoms and 0, 1, 2 or 3 double bonds and R6 and n are as defined above.

~3 ~

Suitable f~y acid amide ~olYalvcol ethers are adducts of on average n mol ethylene and/or propylene oxide with fatty acid amides corresponding to formula ~XXII) Rl8-CO-NH~OCH2CH)nO~
R~

in which R~8 is an aliphatic hydrocarbon radical containing 5 to 21 carbon atoms and 0, l, 2 or 3 double bonds and R6 and n are as defined above.
Suitable fatty amine Dolyalvcol ethers are adducts of on average n mol ethylene and/or propylene oxide with fatty amines corresponding to formula ~XII$) R18~ OCH2CH ) DOll (X~

in which R19 is an alkyl radical containing 6 to 22 carbon atoms and R6 and n are as defined above.
Suitable mixed ethers are reaction products of fatty alcohol polyglycol ethers with alkyl chlorides correspond-ing to formula ~XXIV) R2o-~oc~2cH)n-o-Rzo ~XXIV) R~

in which R20 is an aliphatic hydrocarbon radical containing 6 to 22 càrbon atoms and 0, 1, 2 or 3 double bonds, RZ i~
an alkyl radical containing 1 to 4 carbon atoms and R6 and n are as de~ined above.
Suitable hvdroxy mixed ethers are compounds corre-sponding to ~or~ula ~X~V) R2l-C~~C~ OC~2C~I) n--O-R22 ~V) OH R~

a in which RZl is an alkyl radical containing 6 to 16 carbon atoms, R22 is an alkyl radical containing 1 to 4 carbon atoms and R6 and n are as defined above. The production of the hydroxy mixed ethers is described in German patent application DE-A-37 23 323.
Suitable alk~l alvcosides are compounds corresponding to formula ~rvI) R23-o-~G)~ ~XXVI) in which G is a symbol for a glycose unit derived from a sugar containing 5 or 6 carbon atoms, x is a number of 1 to 10 and R23 is an aliphatic hydrocarbon radical containing 6 to 22 carbon atoms and 0, 1, 2 or 3 double bonds. G is preferably a glucose unit and x is a number of 1.1 to 1.6.
The production of the alkyl glycosides is described, for example, in German patent application DE-A-37 23 826.
If the esters of dicarboxylic acids with fatty acid monoalkanolamides are used in admixture with other anionic or nonionic surfactants rather than on their own, these mixtures advantageously contain 5 to 95S by weight and preferably 10 to 60% by weight of the ester.
To obtain economically useful results in the flotation of non-sulfidic ores, the surfactant mixture has to be used in a certain minimum quantity. At the same time, however, a maximum quantity of the surfactant mixture must not be exceeded either because otherwise foaming would become excessive and selectivity with respect to the valuable minerals would diminish.
The quantities in which the esters or their mixtures with other anionic or nonionic sur~actants in the context of the invention are used are determined by the type of ores to the floated and by their content of valuable minerals. Accordingly, the particular quantities required may vary within wide limits. In general, the esters to be used in accordance with the invention or mixtures thereof with anionic or nonionic surfactants are used in quantities of 50 to 2,000 g and preferably in quantities of 100 to 1,500 g per tonne crude ore.
The process according to the invention also includes the use of typical flotation reagents such as, for example, frothers, regulators, activators, deactivators, etc. The flotation process is carried out under the same conditions as state-of-the-art processes. In this connection, the following literature references are cited as technological background in the processing of ores: H. 8chubert, "Aùf-bereitung fester mineraliscber 8toffe", Lo~pzig, 1967: D.B.
Pu¢haJ tEd.)~8olid/Liguid 8epar~tion ~quipment 8cale-up~, Croydon, 1977t ~.8. Perry, C.J. VanOss, ~. Grush~a (~
"8eparation and Purification Mstho~s", New Yor~, 1973 -1978.
The process according to the invention is preferably used for the flotation of salt-type minerals, more particu-larly apatite ores.
The following Examples are intended to illustrate the invention:

- Ex~mples I. Collectors and oo-collectors used A) Collectors Al) maleic acid/oleic acid monoethanol-amide ester, Na salt A2) itaconic acid/oleic acid monoethan-olamide ester, Na salt A3) C,~ dicarboxylic acid/oleic acid monoethanolamide ester, Na salt A4) maleic acid/stearic acid monoethan-olamide ester, Na salt B) Co-collectors 81) alkylsulfosuccinate-Na/NH,salt based on maleic acid mona-oleyl/cetyl 1) ester B2) technical oleic acid iodine value 95, Edenor A-Tio5 (crude), Henkel KGaA

C) Depressor Cl) phenol-formaldehyde condensate Suspendol~PPK, Henkel KGaA
II. Preparation of the collo¢tors accordinq to the ~nven-tion , Prepar~tion of maleic acid/ol-ic aci~ mono-thanolam~e ~t-r, N~ 8~1t ~A1) 200 g (0.6 mol) oleic acid monoethanolamide are intro-duced into and heated to 90-C in a 500 ml three-necked flask equipped with a stirrer, internal thermometer and reflux condenser. 62 g (0.63 mol) maleic anhydride were introduced into the melt in portions and the reaction mix-ture was stirred for 90 minutes at 95-C. Thereafter, potentiometric determination with sodium hydroxide revealed a residual content of unreacted anhydride of approximately 2.5% by weight. 120 g of the acidic ester obtained were then dissolved with 11.5 g sodium hydroxide in a mixture of 100 ml water and 60 ml ethanol, followed by stirring for 60 minutes at 80-C. Finally, the solvent was distilled off at 80-C/20 mbar. 129 g of the sodium salt of the ester were obtained in the form of a yellow solid.
Preparatlon of ltaconio acld/oleic acid mo~oethanolamide ~ter, Na s~lt ~a2 ) Al was repeated using 70 g (0.63 mol) itaconic an-hydride. The Na salt was obtained in the form of a brown solid.

zr~3~8 D 91~0 14 Pr-paration o~ C~icarboYylic acid/ol-ic aci~ nono-thanol-aoi~- est-r, Na ~alt ~A3) 28.1 g (0.08 mol) oleic acid monoethanolamide, 14.6 g (0.1 mol) of a technical C,~ dicarboxylic acid monomethyl ester mixture (succinic acid/glutaric acid/adipic acid ester = 1 : 1 : l, Rhone-Poulenc) and 0.25 g methanolic sodium methylate solution (30% by weight) were introduced into a 250 ml distillation apparatus and reacted at 96-C/2S
mbar, methanol being continuously distilled off. 0.25 g sodium methylate solution was added after S h and after 7 h. After a total of 13 h, the reaction was terminated.
The crude esterification product was then saponified with sodium hydroxide solution for 2 h at 96 C.

lS Preparation of mal-ic aci~/~tearic acid monoethanolamido est-r, Na salt ~a~) Al was repeated using 200 g (0.6 mol) stearic acid monoethanolamide. The reaction was carried out at 10S-C.
The crude reaction product had a residual anhydride content of 4% by weight. Neutralization was carried out in the same way as described in Al).

III. Plotation te~ts in a Denver cell Examples l to 5: ComDarison Example l:

~lotation of apatit- or-The flotation batch was a low-grade apatite ore con-taining a high percentage of siliceous gangue and having the following composition (based on the principal constitu-ents):

P20, : 4% by weight sio2 : 38% by weight CaO : 10% by weight MgO : 16% by weight ' D 9130 15 ~J~ A8 The flotation batch had the following particle size distribution:

- 40 ~m : 20.8% by weight 40 - loo ~m : ls.o~ by weight loo - 200 ~m : 29.1% by weight 200 - 500 ~m : 26.5% by weight > 500 ~m : 4.6~ by weight The collectors according to the invention were used on their own or in combination with an alkyl sulfosuccinate Na/NH4 salt (B1) or a technical oleic acid (B2) as co-collectors, the collector and co-collector being mixed in a ratio of 50 : 50 to 70 : 30 parts by weight. A technical oleic acid dissolved with sodium hydroxide solution was used for comparison.
In the rougher flotation step, the ore was floated in a Denver type Dl 2 liter laboratory flotation cell, the cleaning stages (2 to 4 scavengings) being carried out in a corresponding l liter cell. Water having a hardness of 3~d (d = German hardness) was used as the flotation water;
the pulp density during rougher flotation was approx. 500 g/l. A phenol-formaldehyde condensate (Cl) was used as depressor in a quantity of 200 g/t. The pH value of the pulp was ad~usted to pH 10 with sodium hydroxide.
The reagents were conditioned with stirring at a speed of 1,000 r.p.m., the conditioning time being 5 minutes both for depressor and for collector. Flotation was carried out at a speed o~ l,lO0 r.p.m. (2 liter cell) or l,000 r.p.m.
(1 liter cell). The flotation time was approximately 4 minutes during which the flotation froth was stripped by hand.
In the cleaning flotation stages, the rougher concen-trate was introduced into the 1 liter cell in the absence of reagents and floated for approx. 4 minutes at l,OOo D 9130 16 ~33~8 r.p.m. Example 1 and Comparison Example 1 were carried out with four cleaning stages while Examples 2 to 5 were carried out with two cleaning stages. The results are summarized in Table 1.
Examples 1 to 5 show that, where the esters are used as collectors in the context of the invention, a higher recovery of P20s can be obtained than with the standard collector, oleic acid, for the same dosage. Where the esters are combined with standard collectors, an increase in selectivity with respect to the valuable minerals is observed, so that less cleaning stages are required to obtain marketable mineral concentrates.

Table 1:
- Flotation of low-grade apatite ore in a Denver cell;
percentages as % by weight Ex- Collector OU FS B C1 ~ NC
ample g/t % % % %
, 1 Al 150 rt73.7 0.18 4 4 ct12.3 0.86 3 conc 14.024.44 93 2 Al (50% by weight) 120rt 81.5 0.30 6 2 B2 (50% by weight) ct 10.9 5.74 16 conc 7.635.51 68 . :

Table 1: (continued) Flotation of low-grade apatite ore in a Denver cell:
percentages as % by weight Ex-Collector OU FS R Cl ~B NC
ample g/t % ~ % %

3A2 (50% by weight)120 rt80.3 0.19 4 2 B2 (50% by weight) sc4.4 2.42 3 ct7.6 5.61 12 for sc: S0 conc7.736.39 81 lS 4A3 (50% by weight)120 rt81.10.26 6 2 B2 (50% by weight~ sc2.9 4.13 4 ct7.9 3.87 9 for sc: 30 sc8.134.38 81 5A4 (70% by weight)213 rt83.60.34 8 2 81 (30% by weight) ct6.3 2.02 3 conc10.131.9289 Cl B2 142 rt72.80.37 8 4 ct14.61.31 5 conc12.624.2187 Legend: QU s quantity of collector used, based on the ore FS ~ flotation stage R = recovery C1 = P20, content PR = P205 recovery NC - number o~ cleanings rt = rougher flotation tailings D 9130 18 ~ 8 ct = tailings of the cleaning stage sc = scavenger flotation scavenging of the rougher flotation tailings in a scavenging cell conc = concentrate IV. Flotation test~ in a modified Hallimon~ tube ExamDles 6 to 8, Comparison Example C2 Flotation o~ 8wedi~h apatite ore The flotation batch was a Swedish apatite ore having the following composition, based on the principal constitu-ents:
P2O5 : 20.1% by weight SiO2 : 32.3% by weight Fe2O3 : 6.3% by weight - CaO : 34.2% by weight The ore was present in already ground form in the pulp. After wet screening, a particle size fraction of 50 to 100 ~m was used as the batch. The flotation cell used was a modified Hallimond tube with a volume of 165 ml and a stirrer speed of 400 r.p.m. Quantities of 2 g ore (dry content) were conditioned and floated at pH 10 (adjusted with sodium hydroxide) in water having a hardness of 20-d (calcium ions only). The conditioning time was 5 minutes for the hard water and 10 minutes for the collector.
Flotation was carried out over a period of 2 minutes.
The collectors according to the invention were used either on their own or in admixture with co-collectors.
The alkyl sulfosuccinate (Bl, Comparison Example C2) was used for comparison. The results of the flotation tests are summarized in Table 2.

D 9130 19 ~r~
By comparison with standard collectors, Examples 6 to 8 show that the use of the esters of dicarboxylic acids with fatty acid monoalkanolamides, either on their own or in admixture with standard collectors, as collectors in accordance with the invention improves both the phosphate content of the concentrate and also the bulk recovery and hence the phosphate recovery.

Table 2:
Flotation of Swedish apatite ore in a modified Hallimond tube;
percentages as % by weight Ex- Collector QU B PR PC EC SC
ample g/t % % % %

6 A2 200 33 64 40 1.4 1.3 7 A3 (50% by weight) 200 36 71 40 1.2 1.9 B1 (50% by weight~

8 A1 (50% by weight) 100 30 57 38 1.0 1.9 B2 ~50% by weight) C2 B1 200 27 51 38 1.7 3.8 .

Legend: QU = quantity of collector used, based on the ore FS = flotation stage R = recovery PR ~ P2O, recovery PC 2 P2O, concentrate content EC = Fe2O3 concentrate content SC = SiO2 concentrate content

Claims (9)

D 9130 20

1. A process for the recovery of minerals from non-sulfidic ores by flotation, in which ground ore is mixed with water to form a suspension, air is introduced into the suspension in the presence of a collector system and the foam formed is stripped together with the floated solids present therein, characterized in that esters of dicar-boxylic acids with fatty acid monoalkanolamides correspond-ing to one of formulae (I) to (VI) below R1-CO-NH-CH2-CHR2-O-CO-(CH2)m-COOX (I) R1-CO-NH-CH2-CHR2-O-CO-CH=CH-COOX (II) (III) (IV) (V) (VI) in which R1-CO is an acyl radical containing 6 to 22 carbon atoms and 0, 1, 2 or 3 double bonds, R2 is hydrogen or a methyl group, m is a number of 1 to 10 and X is hydrogen, an alkali metal or an ammonium ion, are used as collectors.

2. A process as claimed in claim 1, characterized in that esters derived from maleic acid, succinic acid, glutaric acid, adipic acid, citraconic acid or itaconic acid and mixtures of these acids with one another are used as collectors.

3. A process as claimed in at least one of claims 1 and 2, characterized in that esters in which R1-CO in formulae (I) to (VI) is an acyl radical containing 12 to 18 carbon atoms and 0 or 1 double bond are used as collectors.

4. A process as claimed in at least one of claims 1 to 3, characterized in that R2 in formulae (I) to (VI) is hydro-gen.

5. A process as claimed in at least one of claims 1 to 4, characterized in that mixtures of esters corresponding to formulae (I) to (VI) and anionic surfactants selected from the group consisting of fatty acids, alkyl sulfates, alkyl ether sulfates, alkyl sulfosuccinates, alkyl sulfosuccin-amates, alkyl benzene sulfonates, alkyl sulfonates, petrol sulfonates, acyl lactatec, sarcosides, alkyl phosphates and alkyl ether phosphates are used as collectors.

6. A process as claimed in at least one of claims 1 to 4, characterized in that mixtures of esters corresponding to formulae (I) to (VI) and nonionic surfactants selected from the group consisting of fatty alcohol polyglycol ethers, alkyl phenol polyglycol ethers, fatty acid polyglycol esters, fatty acid amide polyglycol ethers, fatty amine polyglycol ethers, mixed ethers, hydroxy mixed ethers and alkyl glycosides are used as collectors.

7. A process as claimed in at least one of claims 5 and 6, characterized in that mixtures in which the content of esters corresponding to formulae (I) to (VI) is 5 to 95% by weight are used.

8. A process as claimed in at least one of claims 1 to 7, characterized in that the collectors are used in quantities of 50 to 2,000 g/t crude ore.

9. A process as claimed in at least one of claims 1 to 8, characterized in that salt-type mineral are used as the crude ores.