CA2092440A1 - 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 Salts of esterification products of maleic acid with oligoglycerol partial esters corresponding to formula (I) (I) in which R1, R2, R3 and R4 independently of one another represent hydrogen, a saturated aliphatic acyl radical contain-ing 8 to 18 carbon atoms or a CO-CH=CH-COOX- group, X is an alkali metal or ammonium and n is 0 or a number of 1 to 18, with the proviso that at least one of the substituents R1 to R4 is an acyl radical and at least one is a CO-CH=CH-COOX
group, optionally in admixture with other anionic or nonionic surfactants, are suitable as collectors for the flotation of non-sulfidic ores, more particularly apatite.

Description

2~244~
- HENKE~ KGaA
Dr. Fb/46 20th September, 1990 Patent Application A proce~s for the r~covery of mi~or~ls from no~-~ulfi~ic ores by ~lotatio~

This invention relates to a process for the recovery of minerals from non-sulfidic ores by flotation, in which salts of esterification products of maleic acid with oligo-glycerol partial esters, 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 normally subjected to preliminary size-reduction, dry-ground, but preferably wet-ground and suspended in water.
A collector is then added, often in conjunction with other reagents, including 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 reagents 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 during the aeration step. The mineral constituents are selectively hydrophobicized so that the unwanted constituent~ 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 flota-- 2~3~4~0 ,~

tion is to recover t~e valuable miner~l of the ores in a~
high a yield as possible while at the same timQ obtaining high enrichment 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 - 10 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 tAufbereitungstec~ni~, 26, 632 (198S)], 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 of a reagent system and the foam formed is stripped off together with the floated solids present therein and in which salts of esterification products of maleic acid with oligoglycerol partial esters corresponding to formula ~I) R1-o-c~l2-cH-cH2-o- tCH2-CH-CH2] n R ( I ) o_R3 O-R

in which R1, R2, R3 and R4 independently of one another represent hydrogen, a saturated aliphatic acyl radical contain-ing 8 to 18 carbon atoms or a CO-CH=CH-COOX- group, :;

2~24~
.

X i~ an alkali metal or ammonium and n is 0 or a number oS 1 to 18, with the proviso that at least one of the substituents R1 to R~ is an acyl radical and at least one is a CO-CH-CH-COOX
group, are used as collectors.
It is of particular advantage to use salts correspond-ing to formula ~I), in which n is a number of 2 to 5 and Rl is a saturated acyl radical containing 12 to 18 carbon atoms.
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, ind also certain silicates and alumosilicates.
The salts of the esterification products of maleic acid with oligoglycerol partial esters are known compounds and may be obtained by the relevant methods of preparative o~ganic chemistry. For example, oligoglycerols, i.e. self-condensation products of glycerol having average degrees ofcondensation o~ 2 to 20, may be reacted wit~ fatty acids to oligoglycerol partial esters still containing free hydroxyl groups, one or two of these OH functions may be esteri~ied with maleic acid and the unesterified acid func-tions o~ the dicarboxylic acid component may be subsequent-ly neutralized with aqueous alkali hydroxide. Correspond-ing processes are described in 8eifen-Ole-Fette-Wachs~ 10~,

3 ~19781 and Parfum. Kosm. 60, 37 (1979).
Typical fatty acids which may be present as components in the salts corresponding to formula (I) are caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid and stearic acid. As usual in oleochemistry, the fatty acids may also be present in the form of tech-nical mixtures, for example of the type formed after the lipolysis of natural fats and oils (for example coconut 2a~2ll~o oil, palm oil, pal~ kernel oil, rapeseed oil, sunflower oil or beef tallow) under pressure and subsequent hydroqen-at~on.
The reaetion of the fatty acid with the oligoglycerol S lead~ to a statlstical mixture of ester~ differing in their substitution pattorn. To prepare oligoglyeerol partial esters, oligoglyeerol and fatty aeid are used in a molar ratio of 1:1 to 1:2. Under these conditions, the resulting esterifieation products corresponding to formula (I) eontain at least one primary fatty acid ester group.
Commensurate with the number of free hydroxyl groups in the oligoglyeerol partial esters formed, their subsequent esterifieation with maleie aeid or malei~ anhydride also ~ollows statistieal laws. If primary hydroxyl groups are still present, it may be assumed that they are esterified first. The reaetion of oligoglyeerol partial ester and maleic acid takes plaee in a molar ratio of 1:1 to 1:2.
$he formation of oligoglyeerol esters bridged by a maleie acid group is also possible, albeit to a limited extent.
Accordingly, the salts of these esterification products to be used in aeeordanee with the invention are complex mixtures.
The proeess according to the invention enables the salts of esterifieation products of maleic acid with oligoglycerol partial esters to be used as collectors for the reeovery of minerals from non-sulfidic ores by flota-tion either on their own or in the presence of other anionie or nonionie surfactants.
In the eontext of the invention, anionic surfactants are fatty aeids, alXyl sulfates, alkyl ether sulfates, al-kyl sulfosueeinates, alkyl sulfosuccinamates, alkyl benzene sul~onates, alkyl sulfonates, petrol sulfonates, acyl lact-ylates, sareosides, alkyl phosphates and alXyl ether phos-phates. All these anionic surfactants are known compounds of whieh the production - unless otherwise stated - is de-

4 ~ ~

scribed, for example, in J. Falb~, U. Raasorodt ~ed.), ~ataly~toren, Tons~de und Mineraloladditivo~, $hl-me Ve~lag, 8tuttgart, 1978 or J. Falb- ~ed.) ~8urf~ct~ts in Consumor Produot~, 8p~in~er Verl~g, ~orlin, 1986.
Suitable fattY a~id~ are, above all, the linear fatty acids corresponding to formula (II) R5-Cooy (~I) in which R~ 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 talI oil fatty acid.
Suitable alkvl sulfates are the water-soluble salts of sulfuric acid semiesters of fatty alcohois corresponding to formula (III) R6-0-803Z (III) in which R6 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 alkvl ether sulfates are the water-soluble salts of sulfuric acid semiesters of fatty alcohol polygly-col ethers corresponding to formula (IV) R7--(OCII2CH) nO803Z ~ IV) Rt in which R7 is a linear or branched alkyl radical contain-ing 8 to 22 and preferably 12 to 18 carbon atoms, R~ is 2~32~0 . .

hydrogen or a methyl group, n is a number of 1 to 30 and preferably 2 to 15 and Z is a~ defined above.
Suitable alkvl sulfosuccinates are sulrosuccinic acid monoesters of ~atty alcohols corresponding to formula ~V
R~-OOC-C~-C~-C002 ~V) 8035~

in which R9 is a linear or branched alkyl radical contain-` ing 8 to 22 and preferably 12 to 18 carbon atoms and Z is as de~ined above.
Suitable alkYl sulfosuccinamates are sulfosuccinic acid monoamides of fatty amines corresponding to formula (V~) al--N~-OC-C~2--C~-COOZ(VI) 8o3~
in which Rl is a linear or branched alkyl radical contain-ing 8 to 22 and preferably 12 to 18 carbon atoms and Z is as de~ined above.
Suitable alkyl benzene sulfonates are compounds corre-sponding to formula (VII) R -CJH~-803Z (VII) in which R1l is a linear or branched alkyl radical contain-ing 4 to 16 and preferably 8 to 12 carbon atoms and Z is as defined above.
Suitable al~yl sulfonates are compounds corresponding to ~VIII) R~-803Z (VIII) ~24~

in which R~ is a linear or branched alkyl radical contain-ing 12 to 18 carbon atom~ and Z is as defined above.
Suitable ~etrol ~1~9~9S~ are compound~ obtained by reaction of lubricating oil ~ractions with sul~ur trioxid~
or oleum and subsequent neutralization with sodiu~ hydrox-ide. Particularly suitable petrol sul~onates are products in which the hydrocarbon radicals predominantly have chain lengths of 8 to 22 carbon atoms.
Suitable acYl lactYlates are compounds corresponding to formula (IX) ~l3-co-o-C~-coo8 (IX) I

C~
in which Rl3 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 D~-A-32 38 060.
Suitable sarcosides are substances corresponding to formula (X) c~3 Rl~-CO-~-CH2-COO~ ~X) in which R" is an aliphatic hydrocarbon radical containing 12 to 22 carbon atoms and 0, 1, 2 or 3 double bonds.
Suitable alkYl phosphates and alkYi ether ~hosphates are compounds corresponding to formulae ~XI) and ~XII), Rl5- ~OC82CH2) pO O
P/ ~X~) Rl6- ~OCI~2C82) qO OZ

2092~40 and R~-lOC~C~21~O O ~XII) \p//
/ \
~0 o~

in which Rl5 and R~ 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.
I~ the salts to be used in accordance with the inven-tion are used in admixture with alkyl phosphates or alkyl ether phosphates, the phosphates may.be present in the form o~ mono-or diphosphates. In this case, mixtures of mono-and dialkyl phosphates of the type obtained in the indus-trial 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 polygl~col esters, fatty acid amide polyglycol ethers, fatty amine polyglycol ether~, mixed ethers, hydrsxy mixed ethers and alkyl qlyco-sides. All these nonionic surfactants are known compounds of which the production - unless otherwise stated - is described in J. Falbo, U. Hasserodt (ed.), "Xatalysatoren, T-n~ld- und Mlneraloladditive", Thieme Verlaq, ~tuttgart, ; 30 1978 or J. Falbe led.) "Surfactants in Consumer Products~, Spr~nger Verlag, Berlln, 1986.

Suitable ~attv alcohol Polvalycol ethers are adducts of on average n mol ethylene and/or propylene oxide with ~atty alcohols corresponding to formula (XIII) R lOC~2 1 ~) nlI lXIII ) RS

-- .

2092~4~

in which Rl7 is a linear or branched alkyl radical contain-ing 8 to 22 and preferably 12 to 18 carbon atoms, R~ is hydrogen or a methyl group and n is a number o~ 1 to 30 and pre~erably a number of 2 to 15.
S Suitable alkYl ~henol polyalvcol ether.s are adducts o~
on average n mol ethylene and/or propylene glycol with alkyl phenols corresponding to formula ~XIV) R~--c~a~-~oc~2c~) DO~ (XIV) R

in which R~ is an alkyl radical containing 4 to 15 and preferably 8 to 10 carbon atoms and R~ and n are as defined apove.
Suitable fattY aci1 DolYqlycol esters are adducts of on average n mol ethylene and/or propylene oxide with fatty alcohols corresponding to formula (XV) Rl9-Co(oc~2l )DO~ ~XV) in which R~9 is an aliphatic hydrocarbon radical containing

5 to 21 carbon atoms and 0, 1, 2 or 3 double bonds and R8 and n are as defined above.
Suitable fattY acid amide polyalycol ethers are adducts of on average n mol ethylene and/or propylene oxide with fatty acid amides corresponding to formula ~XVI) R20-CO-NJI(OCH2C8)DOH (XVl) in which R20 is an aliphatic hydrocarbon radical containing 5 to 21 carbon atoms and 0, 1, 2 or 3 double bonds and R3 and n are as defined above.

2~2 ~

Suitable ~attY a~ine pol,Yalvcol ~h~L~ are adducts Or on average n mol ethylene and/or propylene oxide with fatty amines corresponding to formula ~YVII) S R21~ oc~) no~
.' 1~
in which R21 is an alkyl radical containing 6 to 22 carbon atoms and R~ and n are as defined above.
Suitable mixed ethers are reaction products of fatty alcohol polyglycol ethers with alkyl chlorides correspond-ing to formula ~XVIII) ~ -(oCH2CH)n-o-R23 (XVIII) R~

in which R22 is an aliphatic hydrocarbon radical containing

6 to 22 carbon.atoms and 0, 1, 2 or 3 doublQ bonds, R23 is an alkyl radical containing 1 to 4 carbon atoms and R8 and n are as de~ined above.
Suitable hYdroxv mixed ethers are compounds corre-sponding to ~ormula (XIX) R~-C~-CH2-(OCH2CH)n-o-a25 ~XIX) 0~ R~

in which R24 is an alkyl radical containing 6 to 16 carbon atoms, R2s is an alkyl radical containing 1 to 4 carbon atoms and R8 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 alkYl alYcosides are compounds corresponding to ~ormula ~XX) 2o~2lll~o R~-o-~G)~ ~X~

in which G is a symbol for a glycose unit derived from a sugar containing 5 or 6 carbon atoms, x is a nu~ber of 1 to lo and R26 is an aliphatic hydrocarbon radical containing 6 to 22 carbon atoms and 0, 1, 2 or 3 double bond~. G is preferably a glucose unit and x is a number o~ 1.1 to 1.6.
The production of the alkyl glyco~ides is described, for example, in German patent application D~-A-37 23 826.
If the salts of esterification products of maleic acid with oligoglycerol partial esters are used in admixture with other anionic or nonionic surfactants rather than on their own, these mixtures advantageously contain S to 95%
by weight and preferably 10 to 60% by weight of the salts of esterification products of maleic acid with oligoglycer-ol partial esters.
To obtain economically useful results in the 10tation o~ 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 salts of esterification products of maleic acid with oligoglycerol partial esters to be used in accordance with the invention or mixtures thereof with other anionic or nonionic surfactants are used are determined by the type of ores to be floated and by their content of valuable minerals. Accordingly, the particular quantities required may vary within wide limits.
In general, the salts of esterification products of maleic acid with oligoglycerol partial 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 l,S00 -` 2 ~ ~ 2 ~ 0 g per tonne crude ore.
The process accordinq to the invention also includes the use of typical ~lotation reagents such as, for example, frothera, 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, "Aur-b-r-itung fester mi~er~ ch-r 8toff-", ~-ipzig, 1967; D.B.
Pucha~ .), "801id/Liguid 8epar~tion Eqyipmont 8c~1e-up~', Croydon, 1977s B.8. Perry, C.J. V~DO~8, E. Grushk~ (Bd.), ~8eparation an~ Pur~fication Methods", Ne~ York, 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. Collector~ and co-collector~ use~

A. Collector corresponding to general formula (I) The composition of the collectors of general formula ~I) R -0~CH2~lCH~CH2~0-tc~2-lc~-c~2]n-o-R ~I) 30 o-a 0-R

used i~ shown in Table 1.

~ 2~2~

Table 1: Composition o~ the collectors used R1 RZ R3 R4 n Al C16/l~ CO H H CO-CH-CH-COONa 0 A2 C12~-C H CO-CH=CH-COONa CO-CH-CH-COONa 0 A3 C1V~-CO H H CO-CH=CH-COONa 0 A4 ClVl~ CO Cl2/l4-CO CO-CH=CH-COONa CO-CH~CH-COONa O
A5 ClVl~ CO H CO-CH=CH-COONa CO-CH=CH-COONa 3 A6 C~/lo~CO H H CO-CH=CH-COONa 3 A7 ClVl~ CO H H CO-CH=CH-COONa 3 A8 C~/~0-CO H H CO-CH=CH-COONa O

B) Co-collectors Bl) Alkyl sulfosuccinate-Na/NH~ salt based on maleic acid mono-oleyl/cetyl (1:1) ester B2) Oleic acid sodium salt, iodine value 95, Edenor- ATiOs (crude), ~enkel KGaA

B3) Oleic acid sodium salt, iodine value 98, basis rapeseed oil (new culture ,containing approx. 90% by weight oleic acid) C) De~ressor C1) Phenol-formaldehyde condensate Suspendol~PPK, Henkel XGaA

--- 20~2~

I~. Pr-p~r~tion o~ th- salts o~ est-rirlG-tlon pr~uot~
of m~l-lc acld ~itb ollaoqlyc-rol ost-r-N~ s~lt o~ ~l-lo old s~i-ster of d~glyc-rol ~onolaurat-s ~a3).
498 g (3 mol) technical diglycerol were introduced into a 1 liter three-nec~ed flask equippQd with a stirrer, reflux condenser, water separator and internal thermometer, followed by the addition of 625 g (3 mol) of a technical lauric acid (C chain distribution: 2% by weight C10, 72% by weight Cl2, 26% by weight C~). The reaction mixture was heated for a period t of 4 h to a temperature T of 180 to 200-C while nitrogen was passed through, the water of condensation distilling off and being removed th~ough the ~ater separator. The crude esterification product was then heated for another 2 h at 180 to 200-C under a reduced pressure of 15 mbar. The diglycerol monolaurate obtained had the following characteristic data:
.

Hydroxyl value : 420 Saponification value : 167 Acid value : 0.8 54.9 g (0.56 mol) maleic anhydride were added in portions at 60 to 70-C to 200 g (0.56 mol) of the diglycer-ol monolaurate obtained, followed by stirring for 3 h at lOO-C. The acidic maleic acid semiester of the diglycerol monolaurate thus formed was then neutralized with aqueous sodium hydroxide solution and adjusted to pH 7.
N~ s~lt o~ the maleic acid semiester of pentaglycerol mono-C0~lO-fatty ~ci~ ester ~A6) In the same way as for the production of A3, 776 g (2 mol) technical pentaglycerol were reacted with 309 g (2 mol) of a CO/,o fatty acid mixture ~C chain distribution: 2~

2032~
, by weight C~, 60% by weight C8, 35% by weight Cl0, 3% by weight C12) firat for 7 h at 180 to 200-C and normal pressure and then for l h at 180 to 200-C under a reduced pressure of 15 mbar. The pentaglycerol fatty acid partial ester had the following characteristic data:

Hydroxyl value : 612 Saponification value : 108 Acid value : 0.3 207 g (0.4 mol) of the pentaglycerol partial ester obtained were reacted for 3 h at 100-C with 39.2 g (0.4 mol) maleic anhydride and then neutralized.
.

lSI. Flotation tosts in a modified Hallimon~ tube Examles l to 10, Compariso~ Examples C2 - C4 Flotation of 8~-dish apatit- or-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 Al2O3 : 5.1% 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 2~2~l10 (calcium ions only). The conditioning time was 5 minutes for the hard water and 10 minutes for the collector.
Flotation was carr$ed out over a period of 2 minutes.
The collectors according to the invention were used either on their own or in admixture with th~ co-collectors (alkyl sulfosuccinate sodium salt, Bl, and olelc acid sodium salt, B 2); B1 and B2 were also used individually ~or comparison. The results of the flotation tests are summarized in Table 2.
Examples 1 to lO show that salts of esterification products of maleic acid with oligoglycerol partial esters may be used with advantage both as collectors, but espec-ially as co-collectors in admixture with other anionic or nonionic surfactant~ in the flotation of non-sulfidic ores.

Table 2:
Flotation of Swedish apatite ore in a modified Hallimond tube;
percentages as % by weight Ex- Collector ~ B Gl G2 G3 ample g/t % % % %

1 Al 200 24 39 1.9 2.8 47 2 A2 200 20 41 1.0 2.6 40 3 A3 ~50% by weight) 200 33 40 1.0 1.9 64 Bl ~50% by weight) 4 A4 ~50% by weight) 200 43 37 1.3 2.4 79 Bl ~50% by weight) -~ 2092440 Table 2: (continued) Flotation of Swedish apatite ore in a modified Hallimond tube:
percentages a-~ % by weight Ex- Collector Q~ ~ 1 G2 G3 EB
ample g/t % ~ % %
.. ..

A5 (50% by weight) 200 34 39 0.8 1.5 65 Bl (50% by weight) 6 A6 (50% by weight 200 31 40 1.0 1.9 62 B1 (50% by weight)

7 A3 (50S by weight) lO0 22 38 1.2 1.7 41 82 (50% by weight)

8 A4 (50% by weight) 100 29 38 1.1 1.9 55 B2 (50% by weight)

9 A5 (50% by weight) 100 25 39 0.8 l.9 48 B2 (50% by weight) A7 (50% by weight) 100 32 39 1.0 2.1 60 B2 (50% by weight) C2 Bl 200 17 39 1.7 4.1 32 C2 B2 200 27 38 1.7 3.8 51 C3 Bl 100 13 40 1.3 2.8 25 C4 B2 lO0 20 40 1.1 2.6 40 2as2~o Leaend: QU = quantity of collector used, based on the ore GR = Gross recovery G1 = P2O5 content G2 = Fe2O3 content G3 = SiO2 content PA = P2O5 recovery ( SC = sio2 concentrate content ) IV. Flotation tests in a De~ver ce~La Examples 11 to 18: Comparison Example C5:

Fiotation of apatite ore lS ; 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):

P2Os : 4% by weight SiO2 : 38% by weight CaO : 10% by weight MgO : 16% by weight The flotation batch had the following particle size distribution:

- 40 ~m : 20.8% by weight 40 - 100 ~m : 19.0% by weight 100 - 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 ~~'2 a ~

~a/NH~ salt ~B1) or a technical oleic acid (~3) as co-collectors, the collector and co-collector being mixed in a ratio of 33 : 67 to 67 : 33 parts by weight. A technical oleic acid dissolved with sodium hydroxide solution was used for comparison (B3).
In the rougher flotation step, the OrQ was floated in a Denver type D1 2 liter laboratory flotation cell, the cleaning stages (2 to 4 scavenging-~) being carried out in a corresponding 1 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 gJt. The pH value of the pulp was adjusted to pH 10 with sodium hydroxide.
: The re~gents were conditioned with stirring at a speed of l,000 r.p.m., the conditioning time being 5 minutes both for depressor and for collector. Flotation was carried out at a speed of 1,100 r.p.m. (2 liter cell) or 1,000 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 1,000 : 25 r.p.m. Examples 11, 14, 16 and 18 and Comparison Example C5 were carried out with four cleaning stages while Ex-amples 12 and 15 were carried out with three and Examples 13 and 17 with two cleaning stages. The results are summarized in Table 3.

Table 3:
Flotation of low-grade apatite ore in a Denver cell;
percentages as % by weight Ex- Collector Q~ FS ~ Gl ~B
ample q/t ~ % % %

lo 11 A4 266 rt 83.1 0.54 13 4 ct 5.3 5.42 8 conc 11.6 24.2479 12 A7 267 rt 83.1 1.55 36 3 ct 10.4 6.34 19 conc 6.5 24.8345 13 Al (40% by weight) 140 rt83.90.49 12 2 B3 (60% by weight) ct 8.65.03 12 . conc 7.5 35.7476 14 A6 (33% by weight) 120 rt86.82.22 55 2 B3 (67% by weight) ct 8.66.31 16 conc 4.6 22.3229 A3 (40% by weight) 88 rt80.20.28 7 3 B3 (60% by weight) ct 11.64.41 14 conc 8.2 34.5679 16 A3 (67% by weight) 153 rt79.10.20 4 4 Bl (33% by weight) ct 6.91.50 3 conc 14.0 24.00 93 17 A6 (33% by weight) 120 rt 86.8 2.22 55 2 B3(67% by weight) ct 8.66.31 16 conc 4.6 22.32 29 20~2~0 Table 3. (continued) Flotation o~ low-grade apatite ore in a Denver cell;
percentages as % by weight Ex- Collector ~ FS ~B ~ NC
ample g/t % % % %

18 A8 (67% by weight) 132 rt 78.8 0.16 4 4 Bl (33% by weight) ct 8.4 1.15 3 conc 12.8 24.82 93 C5 B3 142 rt 72.80.37 8 4 ct 14.61.31 5 conc 12.6 24.21 87 Legend: QU - quantity of collector used, based on the ore FS ~ flotation stage BR = bulk recovery Gl = P2Os content PR = P2O5 recovery NC = number of cleanings - rt = rougher flotation tailings ct = tailings of the cleaning stage conc = concentrate , ~' `

Claims (8)

D 9359 22

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 salts of esterifica-tion products of maleic acid with oligoglycerol partial esters corresponding to formula (I) (I) in which R1, R2, R3 and R4 independently of one another represent hydrogen, a saturated aliphatic acyl radical contain-ing 8 to 18 carbon atoms or a CO-CH-CH-COOX- group, X is an alkali metal or ammonium and n is 0 or a number of 1 to 18, with the proviso that at least one of the substituents R1 to R4 is an acyl radical and at least one is a CO-CH=CH-COOX
group, are used as collectors.

2. A process as claimed in claim 1, characterized in that salts of esterification products of maleic acid with oligoglycerol partial esters esters, in which n in formula (I) is a number of 2 to 5, are used as collectors.

3. A process as claimed in claim 1 or 2, characterized in that salts of esterification products of maleic acid with oligoglycerol partial esters esters, in which R1 in formula (I) is a saturated C12-18 acyl radical, are used as collectors.

4. A process as claimed in at least one of claims 1 to 3, characterized in that mixtures of a) salts of esterification products of maleic acid with oligoglycerol partial esters esters and b) anionic surfactants selected from the group consisting of fatty acids, alkyl sulfates, alkyl ether sulfates, alkyl sulfosuccinates, alkyl sulfosuccinamates, alkyl benzene sulfonates, alkyl sulfonates, petrol sulfo-nates, acyl lactylates, sarcosides, alkyl phosphates and alkyl ether phosphates are used as collectors.

5. A process as claimed in at least one of claims 1 to 3, characterized in that mixtures of a) salts of esterification products of maleic acid with oligoglycerol partial esters esters and b) nonionic surfactants selected from the group consist-ing 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.

6. A process as claimed in at least one of claims 4 and 5, characterized in that mixtures in which the content of salts of esterification products of maleic acid with oligo-glycerol partial esters is 5 to 95% by weight are used.

7. A process as claimed in at least one of claims 1 to 6, characterized in that the collectors are used in quantities of 50 to 2,000 g/t crude ore.

8. A process as claimed in at least one of claims 1 to 7, characterized in that salt-type minerals are used as the crude ores.