CA1273927A

CA1273927A - Amphoteric compound and use thereof

Info

Publication number: CA1273927A
Application number: CA000539242A
Authority: CA
Inventors: Martin Hellsten; Anders Klingberg; Eva Andreasson
Original assignee: Berol Kemi AB
Current assignee: Nouryon Surface Chemistry AB
Priority date: 1986-06-23
Filing date: 1987-06-09
Publication date: 1990-09-11
Anticipated expiration: 2007-09-11
Also published as: SE454275B; FI872674A0; FI83878C; FI83878B; FI872674A; BR8703141A; SE8602772L; SE8602772D0

Abstract

ABSTRACT

Novel amphoteric compounds suitable to be used as collector in a froth flotation process are described. The amphoteric compounds have the general formula in which R1 is a hydrocarbon group having 5-24 carbon atoms, R2 and R3 independently of each other are hydrogen, a hydro-carbon group having 1-12 carbon atoms or the group R1-Xm-X'n-Yt-Y's or as an alternative the whole group designates the ring X is -?- , X' is -?-Y is an alkyleneoxy group derived from an alkylene oxide having 2-4 carbon atoms Y' is

Description

~Z~

AMPHOTERIC COMPOUND AND USE THEREOF .

The present invention relates to a novel amphoteric compound and its use as a collector in a froth flotation pro cess.
The US Patent 4358 368 and the Swedish Patent Appli-cation 8401859-7 and the South African patent application 83/3023 describe the use of amphoteric compounds having a tertiary amino group and a carboxylic group. These collectors have a good selectority for oxide and salt type minerals, such as phosphate minerals, which are enriched in high yields and concentrations.
According to the invention it has been found that a new type of amphoteric compounds in comparison with the prior art exhibits improved selectivity as a collection in a froth 1O-tation process of oxide or salt type minerals, such as mine-rals containing phosphate fluoride, copper, tungsten, niobium or cobalt. The compounds according to the inventio~ exhibit especially good properties when phospate minerals are to be separated from iron ore. By using the amphoteric compound, if desired in combination with a cationic amine collector for silicate, it has proved possible to reduce the content of phosphor in the iron concentrate to 0,03 % or lower, and at the same time to keep the assay of iron on a very high level.
The low content of phosphor facilitates the subsequent metal-lurgical working up of the iron concentrate. The new types of amphoteric compounds according to the invention can be summer~zed with the general formula l2 13 1 m Xn Yt Ys-~N-cpH2p)q-N-c2H4opo3M2 in which Rl is a hydrocarbon group having 5-24 carbon atoms, R2 and R3 independently of each other are hydrogen, a hydro-carbon group having 1-12 carbon atoms or the group Rl-Xm-X n~Yt-Y s or as an alternative the whole group . . .

~ 3~7 2 12 ~3 CH- CH
-N-¦CpH2p)q~N~ designates the ring -N N-is --Il- , X ' is -O--o Y is an alkyleneoxy group derived from an alkylene oxide having 2-4 carbon atoms, ' is -CH2-1H C~2 OH
M is a monovalent cation or hydrogen m, n, and s are 0 or 1, p and q are 1-3 and t is a number from 0 to 5, under the condition that n is 0 when t and s are 0. Preferably, p is 2 or 3.

The compounds according to the invention may easily be manufactured from commercially available starting products by applying well-known process steps.
The group Rl may be derived from an alfa-olefin with 8-20 carbon atoms or a carboxylic acid or a hydroxyl compound. Suitable hydroxyl compounds and carboxyl compounds are Ziegler, Oxo and fatty alcohols, such as butanol/
iso-butanol sec. n-butanol, n-hexanol, sec. hexanols, iso-hexanols, 2-etyl hexanol, n-octanol, lauryl alcohol, myristyl alcohol, cetylalcohol and oleylalcohol and their corresponding carboxylic acids.
Besides aliphatic alcohols and carboxylic acids also cycloaliphatic alcohols and aromatic hydroxyl or carboxyl compounds may be used as starting material. Suitable cycloali-phatic alcohols are cyclohexanol and alkyl substituted cyclo-alcohols. Among suitable aromatic hydroxyl or carboxyl com-pounds, synthetically produced mono-, di- or trialkyl ~ubsti-tuted phenols, such as octyl phenol, nonyl phenol, dodeyl phenol, dibutyl phenol and tributyl phenol ought above all to be emphasized.
The group Y and Y' can by conventional methods be in-troduced by reacting a suitable ~tarting compound with alky-~ 3 lene oxide and epichlorohydrin. The group N-CpH2p can be introduced by using ethylene diamine, diethylene triamine, triethylene tetramine and the corresponding propylene amines as well as alkylsubstituted derivates thereof as reactants.
As an alternative it is possible to use acrylonitrile as a reactant and then hydrogenate.
Compounds according to the invention generally show good properties in flotation of oxide or salt type minerals, such as apatite may well be used when enriching iron minerals from phosphor containing ores in combination with a primary amine as a silicate collector.
Figure 1 shows a flow sheet of such a floth flotation process.
In Stage I the iron ore, together with water, sodium~
hydroxide and sodium silicate, are ground to a particle size, suitable for froth flotation. The ground ore slurry then passes to Stage II, where the ore is pretreated with starch and the pH-value is adjusted with sodium hydroxide, resulting in slime formation. The slime rises to the surface of the slurry, and is removed. The ore is then conditioned for several minutes in Stage III, with addition of more sodium hydroxide to adjust pH, and starch, and then in Stage IV a primary amine and an amphoteric collector are added with more sodium hydroxide to adjust pH, and conditioned for several more minutes. The slurry is subjected to a rougher flotation in Stage IV. The gangue at the surface is removed as Froth Product I, and the bottom iron mineral concentrate passed to the Stage VI conditioning, after addition of more primary amine 9 and sodium hydroxide to adjust pH. After conditioning for se~eral minutes, there follows a second froth flotation seprating a Froth Product 2, and recovering the iron mineral concentrate product~
One class of compounds which is encompassed of the in-vention and which is easy to produce may be summerized with the general formula 3~7 4 o R R
1 ~ 13 l~ N(CpH2p)~ N C2H~OPO3M2 II
in which Rl, R2, R3, and M have the same meaing as in formula I, p is 2 or 3 and q is l to 3.

Compounds having good flotation properties can easily be produced from alfa olefines as starting compounds. These compounds can be summarized with the formula ~2 ~3 RlCH21CHCH2(NCpH2p)q N C2H40PO3M2 III
OH

in which Rl, R2, R3, and M have the same meaning as~ in formula I, p i5 a number 2 or 3 and q is a number from l-3..

Other preferred compounds are those which can be obtained by using among other things a hydroxyl compound and epichlorohydrin. These compounds may be summerized with the formula ~ 2 ~3 RlO~Yt~CH2CHCH2(NCpH2p)q N C2 4 3 2 IV
OH
in which Rl, Y, R2, R3, t and M have the same meaning as in formula I, p is a number 2 or 3 and q is from l to 3.

Another ~roup of compounds according to the invention is the one having the formula IR2 ~3 Rl (NCpH2p)q C2H40P03M2 V

in which Rl, R2, R3, and M have the same meaning as in formula I, and p is a number 2 or 3, and q is 1-3.

~27~27 Still another class of compounds having good flotation properties and being easy to produce are those compounds having the general formula / 2 2~
Rl Xm Xn Yt Y3 N~ ~ N C2H40PO3M2 VI
CH2_CH2 in which R1, X, X , Y, Y , M, m, n, t, and s have the same meaning as in formula I.

Examples of specific compounds suitable to be used in a froth flotation process according to the invention are the following:

O H H
15H31 C NCH2CH2NC~2cH2opo3 2Na+

H H
C9H19-CH2CHCH2NCH2CH2NCH2CH2opo3 2Na OH

etylhexyl-o-cH2clHcH2)2 N CH2CH2NCH2C 2 3 OH

9 l9~o-c2H4o-cH2cHcH2 N CH2CH2 N CH2CH20P3 2Na OH

H H
C16H33--CH21CHCH2(NCH2CH2)2 N CH2 2 3 2Na OH

~ CH -CH

C12H25 ~ OH CH2 CH2 ~ ~.Z73~7 6 C17H33-C-N N CH CH opo 2- 2N +

The flotating properties of the amphoteric compound could be further improved by the presence of a hydrophobic secondary collector, preferably in the form of a polar, water insoluble, hydrophobic substance with affinity to the mineral particles coated with the amphoteric compound. The amphoteric compound is usually added in an amount of from 10 to 1000, pre~erably from 50 to 500 grams per metric ton of ore and the polar, water insolu~le, hydrophobic substance in an amount from 0 to 1000, preferably from 5 to 750 grams per metric ton of oreO In the case the amphoteric compound is used in com-bination with the hydrophobic substance the ration between them may be varied within wide limits but normally it is within the interval from 1:20 to 20:1, preferably from 1:5 to 5:1. The water insoluble hydrophobic substance, which according to the invention may be characterized as a secondary collector consists preferably of a polar substance.
If desired, a conventional emulsifier dissol~ed in a hydro-carbon could also be added in order to obtain a stable emulsion in water and a good distribution. The emulsifier may be a nonionic surface active compound, which in the case it is water insoluble is to be included in the polar substance.
Suitable polar components are water insoluble soaps such as calcium soaps; water insoluble surface active alkylene oxide adducts; organic phosphate compounds, such as tributyl phos-phate, tri- (2-ethylhexyl~phosphate; and esters of carboxylic acids, such as tributyl ester and tri(2-ethyl hexyl~ester of NTA as well as dioctylphthalate.
In the froth flotation process o~ the invention the amphoteric collector could also with preference be utilized in combination with depressing agents. Suitable depressants are hydrophilic polysaccharides substituted with anionic ~ ~7~ 7 groups. The polysaccharides having a relativetly low visco-sity are preferred. The molecular substitution may vary within wide llmits but it is normally within the range from one anionic substituent per polysaccharide molecule to one substituen~ per hydroglucose unit. Example of suitable poly-saccharides are carboxymethylcellulose, sulphomethylcellu-lose, gum arabic, gum karaya, tragacanth, gum ghatti, alginate and starch, such as corn starch and anionic starch derivatives such as carboxymethyl starch and starch phos-phate.
In flotation using the present process pH-regulators may be added as well as depressants and activators in known manners. In most flotation processes the pH-value is of importance in obtaining a good separation. The flotation process of the invention is also dependent of the pH-value and this gives improved possibilities to optimize the separa-tion of different minerals by th~ selection of a suitable pH-value. Thus, the character of the amphoteric compound varies considerably with the pH-value. At a pH-value below 6 it is mainly cationic, while it is chiefly anionic at pH-values above 10, and zwitterionic at a ph-value between 6 and 10. In the separation of ore containing apatite and silicate or apatite and calcite an excellent, selective enrichment is obtained, if the flotation process is carried out at a pH-value from about 8 to about 11. If considered convenient, conventional frothers, and activators could also be added.
General rules are impossible to give in more detail, since each ore finally has to be treated in accordance with its own chemical and physical composition.
The compound and the process of the invention is further illustrated by the following Example.

Example A
O H H
The amide Cl5a31C-N-cH2cH2NcH2cH20H was prepared by reacting 272 grams tl mole) of ~2~73~'7 8 with 104 grams ~1 mole) of aminoethyl ethanolamine H2NCH2CH2NHCH2CH2OH. The released methanol was evaporated at the end of reaction. After the reaction the reaction mixture was titzated and the amount of basic nitrogen was determined.
The yield of the amide compouna was about 93 %.
The amide in an amount of 72 grams (0.2 mole) was then reacted with 35 grams of polyphosphoric acid at 85C for twho hours.
Titrations of the anionic group containing surface active compound confirmed the formation of 15H31C N CH2CH2NCH2CH2OP(OH)2.
The total yield was about 69 ~ and the reaction product ob-tained was a highly visous mass which was soluble in water after neutralization.

Example B
The epoxide 2-etylhexyl-OCH2CHCH2 in an amount of 104 grams (0.48 moles) was reacted with amino-ethyl ethanolamine in an amount of 25 grams (0.24 molesJ for two hours at 70C with formation of the teriary amine:

(2-ethylhexyl-OCH2CIHCH2)2NCH2CH2NCH2CH20H
OH
The amination degree was determined by titration of tertiary nitrogen and was found to be about 91 %.
50 grams (0.093 moles) of the tertiary amine was then reacted with 26 grams of polyphosphoric acid at 70C for two hours.
Titrimetric determination of the anionic group con-taining surface active compound confirmed the formation of the compound:

:~273~3~7 9

2-ethylhexyl-OCH2~HCH2)2NCH2CH2NCH2CH2OP(OH)2 OH O
The product obtained was a highly viscous mass, soluble in water after neutralization.

Example C
Froth flotations were carried out in accordance with the flow sheet shown in Figure 1.
An iron ore containing Fe 3~ %, Si 23.9 % and P 0.044 %, mainly present as hematite 49 ~, silicate ~quartz) 51 ~, and apatite 0.24 ~, was crushed to particles less than 1.7 mm in diameter and homogenized. From the homogenized material por-tions of 6C0 grams each were taken out. The portions were further ground in a laboratory rod mill for 30 minutes to-gether with 400 ml of water, 0.40 g sodium hydroxide and 0.27 g water glass (38 ~ sodium silicate by weight, weight ratio SiO2NaO2 = 3.22, 41.0 Be).
The particle distribution was such that 37 % by weight passed through a 32 /u mesh sieve.
An aqueous mineral pulp 8 liters in volume was prepared from each portion of the ground material. Temperature and pH
were adjusted to about 20C and 10.5, respectively. 0.0675 g of prehydrolyzed corn strach was added, and the whole was conditioned in a paddle mixer for 2 minutes.
The conditioned pulp was allowed to settel for 3 minutes, and then the slime was siphoned off. The deslimed pulp was divided into four fractions and each fraction trans-ferred to a flotation cell and diluted with water to a volume of 0.5 liter. The pH was adjusted to 10.5 with sodium hyd-roxide, followed by the addition of 0.0675 g of the prehydro-lyzed corn starch. After condtioning for 2 minutes, and a final pH adjustment to 11.0, the anionic collector and pri-mary amine collectors were added. The amount of the primary amine was 0.0067 g, and the amount of the anionic collector is given in Table I. After an additional conditioning for 2 minutes, a rougher flotation was carried out, giving a Froth Product 1 and a bottom iron mineral concentrate. The pH was again adjusted to 11 wich sodium hydroxide 0.0067 g of pri-mary amine was added to the bottom concentrate, and the whole conditioned for 2 minutes, followed by another froth flota-tion, giving a Froth Product 2 r and iron mineral concentrate.
The primary amines and anionic group-containing compounds used and the results obtained are shown in Table I.

Pure minerals consisting of fluorapatite, calcite, scheelite, magnesite, quarts, olivine, and fluorite respectively were subjected to froth flotation. Firskly, the minerals were ground and wet screened, and the fractions ~250-400 /um were selected to be used in the froth flotation trials. These fràctions were added in an amount of 0.2 ml to test tubes having a diameter of 15 mm and a length of 120 mm.
10 ml of an aqueous fluid containing 0.01 g/l of a collector according to Table 2 and having a pH of 8 or 11 were added~
whereafter the minerals were conditioned for 5 minutes during stirring.
After the conditioning the water phase was sucked off and water under a pressure of 7 at and saturated with air was injected via a lance. When the pressure of the water is reduced, the air liberated and a froth flotation process was taken place. The amount of floated material was determined visually. The obtained results are shown in Table 3 and 4 below~

a ~,l 0 ~ l`
_I Q, tn ~ ~ ~
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u~ ~ ~ ~ ~ ~ 3 dP~ Q~
~ ~ P ~0 ~
~ ~ O O O ~ dP _I CO O
N N N
Z
h N ~I N

~1 ~ _ m :r: o ~ o .
Z E~

N N ~:1 æ
s~ ~ ~ o ~ ~ o 1~ 1~

O O ~o~ ~ ~ ~; ~ r~

~1 Z ¦ c~ ~ ; Z ~I N

~3~

rd Z
o~
o ~r ~
uN æ
Z o ~ ~r ~ ., Z; ~C ~ ~ o ~ u z z m z o Z ~
r~ ~ O
o _ o o :q o U-Z U
~C ~ o o ~ U
U
I U-O ~~ ~ ~
Z ~ U~CcoU ~U Z U-Z
U Z U-Z Z
~r ~ O ~r ~ o m m I m ~ ::c u x ~ ~ ~ ~ m u ~ u ~. ~ X ~ ~o v ~o ~ Zl~ Z Z m~ u~
oo~ ~ o~u ~ U U
E~ I ~ 0~ 0 ~: ~ l_ r~ ~1 ~ ~ m ~ 5:
~t~
U U -- '' ~ o s~
E~
. . . ~ . o E~,~

~l.?~Z7 n.oooLn~ oo m ~ 0~ a~ u~oOOu -nooo u~u~ooolnoou~ ~ u~o~ noooo r-~ ~`I O N --I ~1 ~
~:
V V

oOO I I I I U~ I I . OU~ I I I I O I I
IJ') ~1 ~, ~ ~1 ~C O O O O U~ U~
I-`) Lt~ I I I ~ O I ~ ~ O C~
P.,~r ~1 Q,~r ~1 ~i o ~ u~ o u7 U7 o O o a) ~ u~ n o ~ o o O ~ ~ O ~ 1` 0 0 . GO CO ~ O ~ ~O ~
~ ~ '7 ~1 o o ~ o u~ o u~ o u~ O U~
~ ~ o In ~D O ~ / CO ~ ~ O
O O

u~ u~ ~ o u~ In O In u~ O o o a~ O -~ N ~ ~I t~l .
d~ _l ~1 OP ~I

a) ~ ~ ~ 1 Q) ~r ~ a) ~ ~ ,~
1-1 ~ h E~ ~1 0 ~ ~

~ 0 ~ o E~ E~ C~. V ~~ o' æ o

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. Amphoteric compound characterized in that it has the general formula I

in which R1 is a hydrocarbon group having 5-24 carbon atoms, R2 and R3 independently of each other are hydrogen, a hydro-carbon group having 1-12 carbon atoms or the group R1-Xm-X'n-Yt-Y's or as an alternative the whole group designates the ring X is -?- , X' is -0-Y is an alkyleneoxy group derived from an alkylene oxide having 2-4 carbon atoms Y' is M is a monovalent cation or hydrogen m, n, and s are 0 or 1, p and q are 1-3 and t is a number from 0 to 5, under the condition that n is 0 when t and s are 0.

2. Amphoteric compound according to claim 1, characterized in that p is 2 or 3.

3. Amphoteric compound according to claim 2, characterized in that it has the general formula II

in which R1, and M have the same meaning as in formula I, R2 and R3 is hydrogen or an alkyl group having 1-4 carbon atoms and q is 1 to 3.

4. Amphoteric compound according to any of the claims 1 or 2 characterized in that it has the general formula III

in which R1, R2, R3, and M have the same meaning as in formula I, p is a number 2 or 3 and q is a number from 1-3.

5. Amphoteric compound according to claim 1, characterized in that it has the general formula IV

in which R1, Y, R2, R3, and M have the same meaning as in formula I, p is a number 2 or 3 and q is from 1 to 3.

6. Amphoteric compound characterized in that it has the general formula VI

in which R1, X, X' Y, Y' m, n, t, s, and M have the same meaning as in formula I of claim 1.

7. Use of an amphoteric compound according to any of the claims 1. 2. 3, 5 or 6 as a collector in a froth flotation process.