ALKYLETHER FROTHING AGENT FOR ORE FLOTATION

AGENT MOUSSANT A BASE D'ALKYLETHER POUR LA FLOTTATION DE MINERAI

English Abstract

A process for concentrating ores by froth flotation in the
presence of a collector and a frothing agent wherein the frothing
agent has the general formula
H?OC3H6)nOCH(CH3)-CH2-CH(CH3)2, in which n is an integer of
from 1.0 to 3Ø

Claims

The embodiments of the invention in which an exclusive
property or privilege is claimed are defined as
follows:
1. A process for concentrating ores by froth
flotation in the presence of a collector and a
frothing agent wherein the frothing agent has the
general formula:

H?OC3H6?nOCH(CH3)-CH2-CH(CH3)2,

in which n is a value of from 1.0 to 3Ø

2. A process as claimed in claim 1, in which
the ore is a copper ore.

3. A process as claimed in claim 1 or 2,
wherein said frothing agent is derived from 2-hydroxy-
4-methyl pentane and mono- or di-propylene glycol.

4. A process as claimed in claim 1 or 2,
wherein said frothing agent is derived from 2-hydroxy-
4-methyl pentane and propylene oxide.

5. A process as claimed in claim 3, wherein
said glycol is mono-propylene glycol.

6. A process as claimed in claim 3, wherein
said glycol is di-propylene glycol.

7. A process as claimed in claim 3, wherein
said frothing agent is in an impure form and comprises
unreacted 2-hydroxy-4-methyl pentane.

8. A process as claimed in claim 4, wherein
said frothing agent is in an impure form and comprises
unreacted 2-hydroxy-4-methyl-pentane.


9. A process as claimed in claim 7 or 8,
wherein said impure form comprises at least 50%w, of
said unreacted 2-hydroxy-4-methylpentane based on the
weight of impure form.

10. A process as claimed in claim 1, 2, 5, 6, 7
or 8, in which n is 1.5.

11. A process as claimed in claim 3, in which n
is 1.5.

12. A process as claimed in claim 4, in which n
is 1.5.

13. A process as claimed in claim 9, in which n
is 1.5.

Description

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133652o

-- 1 --

This invention relates to a process for the
concentration of ores by flotation in the presence of
a collector and a frothing agent.
The use of alkyl mono-ethers of di- and
polypropylene glycol has been suggested before, USP
2,611,485 refers to methyl-, ethyl-, propyl- and butyl
ethers of di-, tri- and tetra-propylene glycol, in
particular the methyl-ether shows on average a good
performance and has been sold on the market for many
years under the trade name Dowfroth~250. However,
presently mined ores have a much lower content of
valuable metals than in the past, this sets ever
increasing demands on the efficiency of the ore-
dressing process and therefore likewise on the
performance of the frothing agent.
We have now found that the mono-alkyl ether
derived from 2-hydroxy-4-methylpentane and mono- or
di-propylene glycol has a very good frothing
performance, particularly for the concentration of
copper ores, molybdenite ores and potash ores.
Accordingly, this invention comprises a process
for concentrating ores by froth flotation in the
presence of a collector and a frothing agent wherein
the frothing agent has the general formula
H~OC3H6~nOCH(CH3)-CH2-CH(CH3)2 in which n is a value
of from 1.0 to 3.0 The present alkyl mono-ethers can
be prepared by any suitable method disclosed in the
prior art; e.g. the process referred to in USP
2,611,485. The frothing agent can be used in an
impure form, i.e. comprising a certain amount of
unreacted 2-hydroxy-4-methylpentane. Preferably the
latter amount is at least 50%w, based on the weight of
the impure frothing agent.


~~

.. . . .

- 1336520
-- 2 --
Likewise, suitable collectors are those which have been
proposed before, many of such agents now being available as
commercial products. Concentrations of collector and frothing
agent to be employed in the process of this invention are also not
different from those applied in prior art methods.
EXAMPLE 1
20 g propylene oxide were reacted with 80 g 2-hydroxy,-
4-methylpentane in the presence of a catalytic amount (1 g) of
sodium hydroxide under a nitrogen atmosphere until a mixture with
a constant boiling point (138.5 C) was obtained. This took 5.6
hours heating under reflux. After cooling and filtration to remove
a small amount of solid, 92.9 g of an amber coloured liquid were
obtained. This liquid was composed of 70 % 2-hydroxy,4-methyl-
pentane and 30 % of a compound with the formula
H~OC3H6~nOCH(CH3)-CH2-CH(CH3)2, n being 1.5.
Chalcopyrite ore having an assay of 0.34 %wt Cu was crushed
to pass 8 mesh. The crushed material was ground in a rod mill
during 35 minutes, at 60 %wt solids in water until 88 % passed 100
mesh. The ground material was diluted with water to 33 % solids
and by the addition of CaO the pH was adjusted to 10. Flotation
experiments were run in a WEMCO ~ laboratory flotation machine
using a 3 1 cell and an impeller speed of 1200 rpm. To the
material in the cell a frothing agent and potassium amyl xanthate
collector were added, the mixture was conditioned and frothed, and
a concentrate collected. This cycle was repeated several times.
The total amount of frother added was 0.042 ml and of collector
13.5 ml of 0.1% solution, and the total time for the several
cycles 10 minutes. The performance of the product of this
invention (frother A), i.e. the amber liquid obtained as described
hereinabove, was compared with that of Dowfroth ~250 (frother
B), a mixture of 20% vol. Dowfroth ~ 50 and 80% vol.
2-hydroxy,4-methylpentane (this mixture is referred to as frother
C) and a mixture of 50% vol. 2-hydroxy,4-methylpentane and 50%

1~36520
-- 3 --
vol. of 2,4-dihydroxy,4-methylpentane (this mixture is referred to
as frother D), and 2-hydroxy,4-methylpentane(frother E).
The results of the flotation runs are included in Table I.

TABLE I

Frother Concentrate assay Copper Recovery
(Cu, %w) (%w)
A 1.04 84.8
B 1.60 79.1
C 1.21 82.2
D 1.64 81.2
E 2.15 77.4

for comparison

From the above data it is seen that the frother of the
invention has a better recovery performance than any of the
comparative frothing agents. It is of particular interest to note
that the high recovery rate shown is achieved when dressing an ore
with a very low Cu-assay, i.e. 0.34 %w Cu only.