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Патент USA US2403481

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Patented July 9, 1946
2,493,481
.METHOD OF CONGENTRA'E‘ENG
Julius Bruce Clemmer and Carl Rampaceh: ‘in
caloosa, Ala., assignors to the United States at
America, as represented by the Secretary of the
Interior
‘ No Drawing. Application February 9, 19%,
Serial No. 576,996
7 Claims.
(Granted under the act oft March 3, 1883, as
amended April 30, 1928; 370 Q. G. 75'?)
' 2
l
with the lignin sulphonates. The metaphos
The invention described herein may be manu
phates and pclyphosphates may be used as sup
factured and used by or for the Government of
plementary reagents in conjunction with various
the United States for governmental purposes
crude or puri?ed liin sulphonates, if desired,
without the payment to us of any royalty there
but are not obligatory in the practice of this in»
on in accordance with the provisions of the act
vention.
of April so, 1928 (Ch. 460, 45 Stat. L. 467).
The lignin sulphonates which we prefer to uti
This invention relates to an improved process
lize as iron oxide depressants in this invention
for concentrating iron ores whereby froth ?ota
are present in and may be derived from the
tion of the siliceous gangue constituents yields
an iron enriched product; more particularly it re Ill?) by-product of the sul?te process of paper making
commonly known as “sul?te liquor.” These
lates to a froth ?otation process employing
anionic collecting agents to effect ?otation of . liquors separated asv waste from the cellulose
' pulp contain soluble salts of the lignin sulphonic
activated siliceous gangue constituents from
acids and other non-ligneous organic substances,
caustic alkaline iron ore pulps while retarding
?otation of the iron oxides with lignin sul 15 such as hydrolyzed carbohydrates, resulting from
phonates.
'
'
An object of this invention is to provide a
froth ?otation process for concentrating iron
oxides in pulps containing them in the presence
of siliceous gangue. A further object is to pro
vide a ?otation process for separating silica from .
iron. oxides employing anion-active collecting
agents A still further object is to provide a ?ota
decomposition of the wood by the acid solutions
used in the pulping process. In the sul?te proc
ess, the lignin in the wood is dissolved by digest
the wood chips with an acid calcium, mag
nesium, or sodium sul?te solution at an elevated
temperature whereby the lignin forms soluble cal
cium, magnesium, or sodium lignin sulphonates
depending on the base‘ employed.
The sul?te
liquors containing the lignin sulphonates and non=
tion process for concentrating iron ores or prod
ucts from the milling of iron ores containing both 25 ligneous materials may be used as the iron oxide
depressants in the practice of our invention or
calcareous and siliceous gangue materials. Still
' the crude sul?te liquors may be puri?ed by known
other objects include the development of a ?o
methods to reject the non-ligneous substances
tation process which will have greater selectivity
and recover a substantially puri?ed lignin sul»
in separating siliceous materials from oxide iron
ore pulps and thereby effect greater operating 30 phonate which may be employed to retard ‘the
economies. Other objects, purposes, and advan
tages of the invention will hereinafter more fully
appear or will be understood from the detailed
description of its practice.
iron oxides in our method of silica ?otation.
The crude or whole sul?te'liquor recovered
from the sul?te pulping process and ‘containing
the lignin sulphonates and non-ligneous organic
In a co-pending application, assigned to the 35 substances, such as hemi-cellulose. and various
sugars, may be evaporated to yield a concentrated
same assignee as the present application, Serial
No. 473,162, ?led January 22, 1943, by Julius - liquid or dehydrated residue for marketing. The
liquid forms as marketed contain about 50 per
Bruce Clemmer and Ballard H. Clemmons, is de
cent water, whereas the powdered forms are sub
scribed a process for bene?ciating iron ores by
froth ?otation wherein anionic collecting agents 40 stantially dehydrated. The liquid and powdered
are employed to ?oat activated siliceous gangue
constituents from caustic alkaline iron .ore pulps
forms have been used interchangeably in our
I method of ?otationand, based on their respec- '
tive content of lignin sulphonate, are equally ef
fective for retardation of iron oxides. Compara
45 tive tests using the calcium, magnesium, and so
phosphates.
'
dium base sul?te liquors, or the respective dehy
As a result of further extended research and
with a pH of at least 10, while, retarding ?otation
of the iron oxides with metaphosphates or poly
dration residues thereof, gave substantially equiv
experimentation, we have discovered an improved
alent results. The non-lignéous materials-pres
method of concentrating iron ores by froth ?ota
ent in the liquid or dehydrated residues appear
tion of activated siliceous gangue constituents
employing anionic collecting agents, such as the 60 to be inactive diluents and exert little or no del
eterious e?ect in the froth ?otation of activated
higher fatty acids, resin acids, mixtures of fatty
siliceous gangue from iron oxides. The evap
and resin acids, and soaps thereof, to ?oat the
activated siliceous materials from caustic alkaline
iron ore pulps with a pH of at least as high as
orated crude sulflte liquors or dehydration resi
dues were slightly less effective pound per pound
10,‘ while retarding ?otation of the iron oxides 55 than the corresponding puri?ed lignin sulpho
2,408,481
nates relatively free of non-ligneous material, but
were particularly attractive as iron oxide de
pressants in our method of flotation due to their
lower cost.
The crude or evaporated sul?te liquors may be
processed by numerous methods to reject the non
ligneous material and recover substantially puri
4
anionic. ?otation and establishing the desired
caustic alkalinity for ?otation by formation of
caustic soda within the pulp. The optimum pH
for anionic ?otation of the activated silica and
retardation of the iron oxides varies slightly for
dl?'erent ores but generally falls within the range
of 10 to 12, and the proper pH for any particular
case is best determined by experimentation. Poor
?otation of the silica and incomplete retardation
mineral acids, lime water, basic lead acetate, or 10 of the iron oxides invariably results if the pI-l of
» organic bases may be employed to recover the
the pulp is much less than 10; a pulp pH greater
?ed lignin sulphonates. Fractional precipitation
methods using sodium chloride, calcium chloride,
lignin sulphonate and reject the non-ligneous
materials. The precipitated lignin sulphonate
than 12 is not particularly objectionable, but the
froth is inclined to be voluminous and ?otation of
may be further puri?ed by dissolution and re
the silica is sluggish. We therefore prefer to keep
precipitation, by dialysis, or other methods. The 15 the pH in the range 10 to 12 in our ?otation
puri?ed sulphonates are ordinarily marketed as
method.
a
the powdered forms but solutions containing from
It is essential in the practice of this invention
15 to 50 percent of the lignin sulphonate are also
that the siliceous gangue constituents in the iron
available. Various of the commercially'available
ore be activated and made ?oatable by the anionic
puri?ed lignin sulphonates containing the cal 20 collecting
agents. The siliceous gangue materials
cium, magnesium, sodium, barium, aluminum,
in certain iron ores, such as the calcareous red '
zinc, and copper salts have been tested and found
ores of the Birmingham district, Alabama, are
satisfactory as iron oxide retardants in the prac
naturally activated to soap ?otation presumedly
tice of our invention. The calcium, magnesium,
due to the presence of lime and/or magnesia salts
and sodium sulphonates are less expensive than 25 in
the ores. siliceous iron ores, as exemplied by
the heavy metal salts and were preferred. The
the weathered red ores of the Birmingham dis
liquid or powdered forms of either the crude or
puri?ed sul?te liquor materials may be used in
our method of ?otation, and the ultimate choice
of the particular lignin sulphonate employed will 30
A variety of liquid and powdered forms of both
largely depend upon economic factors.
‘ crude and puri?ed sul?te liquor products are com
trict and most siliceous ores of the Lake Superior
district, seldom contain naturally activated sili
ceous materials, and the successful operation of
our process requires that the silica in such ores
be activated for anionic ?otation.
Extended re- .
search on a variety of siliceous iron ores demon
strated that our method of ?otation lends itself
mercially available and have been found satisfac
readily to the use of silica activating agents.
tory for retarding iron oxides in our ?otation 35 Many alkaline earth and heavy metal salts'ex
method. Examples of the sul?te liquor materials
hibit the property of activating quartz andvar
which we have used successfully include those
ious silicate minerals to soap ?otation if a proper
sold under the trade names "Bindarene Liquid,”
quantity is employed at an optimum pH. We
“Bindarene Flour,” “Goulac,” “T. D. A.,” “Mara
have found that conditioning of the caustic alka
thon Extracts M, T, NS, TanC, SL, DT-31, DT-32, 40 line iron ore pulp with amoderate quantity of an
DPT-33, DT-34, and DT-35,” and the “Daxads ll,
activator selected from the group consisting of
21 and 23.” Other sul?te liquor products which
soluble calcium, magnesium, barium, strontium,
we have found acceptable include the crude and
and lead salts su?lces to activate the siliceous
puri?ed magnesium lignin sulphonates, the acid,
constituents to anionic ?otation by the higher
neutral, and basic calcium lignin sulphonates, 45 fatty
acids, resin acids, or their derived soaps
and sodium, copper, zinc, aluminum, and barium
without adversely affecting retardation of the
lignin sulphonates. For convenience, we shall
iron oxides by the crude or puri?ed lignin sul
hereinafter use the‘ term “lignin sulphonate” to
phonates. The commercial lignin sulphonates'
include the crude and puri?ed metal salts of
are generally marketed as calcium or magnesium
lignin sulphonic acids, the crude and puri?ed 50 salts
of the lignin sulfom'c acids and as such may
paper mill sul?te liquors, and dehydrated residues
contain su?icient lime or magnesia to activate
thereof.
'
part of the silica in iron ores to ?otation. ,In
While we have achieved satisfactory ?otation '
general, however, the metal salts in the lignin sul
of activated silica from iron ore pulps containing
are insui?cient for complete activation
substantial quantities of slime by the practice 55 phonates
of the silica and supplementary metal Salt acti
of our invention, we prefer that the pulps be de- '
vating agents may be needed for an improved sep
slimed. Desliming of the iron ore pulp should ‘
I be practiced whenever permissible as subsequent
?otation of the activated silica is more rapid and
aration.
'
,
~
In the practice of this invention, We prefer to
employ hydrated lime for activation of the silica.
complete, and less reagents are required.
60 Grinding or blunging the iron ore with sufficient
A caustic alkaline pulp with a pH at least as
hydrated lime to establish a pulp pH of about 11
high as 10, and preferably in the range of 10 to
12, is preferable in our method of ?otation to
facilitate e?ective retardation of the iron oxides
will generally su?lce on most ores for complete ac
tivation of the siliceous gangue. The quantity of
hydrated lime required’to activate the silica in
by lignin sulphonates. We prefer to employ caus 65 iron ores varies from 1 to 4 pounds per ton of ore,
tic alkalies, such. as sodium or potassium hy
but some ores containing acidic salts may require
droxide, or their equivalents, to establish the de
8 pounds or more of hydrated lime per ton. Our
sired pH for ?otation. Moderate quantities of
experiments on a variety of calcareous and silice
other alkaline reagents, such as sodium sul?de,
ous iron ores have revealed that only part of the
sodium carbonate, and sodium silicate, may be 70 hydrated lime added to the ?otation pulp is con
’ used in conjunction with the caustic alkalies if
sumed in activating‘the siliceous constituents to
desired. A combination of hydrated lime and
~ anionic ?otation; part of the added lime may re
soda- ash has been successfully employed in the
act with salts in the pulp and is precipitated as
?otation ‘of many iron ores and served the dual
carbonate, another part is adsorbed by the iron
purpose of activating the siliceous materials to 76 oxides,v still another part remains in solution to
dresser
,
5
_
and ?nally any excess hydrated lime added to the
tannin materials such as quebracho extract, can
extract, and Borneo cutch. These auxiliary ad»
pulp remains undissolved. The lime consuming
capacity differs for different iron ores, and the
proper quantity for activation of the silicais best
in that they enable more e?ective retardation of
the iron oxides with minimal quantities of the
satisfy the solubility requirements of the water,
determined by experimentation. Excessive quan=
titles of dissolved lime in the conditioned pulp
dition agents are advantageous on some iron ores
lignin' suiphonates during anionic ?otation of the
activated siliceous materials.
The proportions of the various reagents em
ployed in the practice of this invention are sub
Ject to considerable variation, and the ‘optimum
achieved by the practice of this invention gem
quantities are best determined by experimenta
?otation of silica from iron ore pulps containing '
dissolved lime equivalent to 1% parts per million I v tion for any particular case. Purity of the sen‘
arated products is a. reliable guide for reagent
of hydrated lime-For about lit pound of hydrated
adjustment. An excess of collecting agent pro
lime per ton of solids in our tests, we prefer that
the ?otation pulp be substantially free 0;? dis- 15 motes ?otation of a portion of the'iron oxides
with the siliceous gangue, whereas a de?ciency
solved lime. The dissolved lime may be removm
of collector results in incomplete ?otation of the
either by washing the conditioned pulp with fresh
siliceous gangue. Conversely, an crew of lignin
water, ‘or by addition of su?lcient soda, ash to pre
sulphonate results in retardation of a portion of,
cipitate the lime as insoluble calcium carbonate.
should be removed before ?otation as they in»
crease collector requirements; Although we have
Brief conditioning of the iron ore with sumcient 20 the siliceous materials, whereas a de?ciency per
mits ?otation of some of the iron oxides with the
hydrated lime to give a pulp with a. pH of about
silica. Control of the collector and lignin sul
11 generally su?lces for complete activation of
the silica. Subsequent addition of soda ash to
the pulp; the requirements for most ores being
1 to 2 pounds per ton of solids, precipitates the
lime in solution and gives a pulp of the desired
caustic alkalinity for ?otation. Should an excess
of hydrated lime be inadvertently added to the
pulp to activate the ‘silica, as evidencedby a pH of
about 12.8, the excess is best removed by settling .30
and washing the pulp one or more times with
phonate is not critical, however, and reasonable
variation in the quantities employed is permis=
sible without adversely a?ecting the separation.
‘To avoid possible confusion in describing the
results of our ?otation test, we shall hereinafter
designate the iron enriched pulps from the rough
ing and cleaning steps as “iron concentrates,
rougher” and “iron concentrates, cleaner,” re
spectively.
The ?oated silica products from the . '
roughing and cleaning steps will be designated
fresh water to reduce the pH to ll, whereupon
as “rougher froth” and “silica rejects,” respec
soda ash may be added to precipitate the remain=
tively. In describing the results of our test we
ing lime in solution before proceeding with flo
consider and report the iron enriched pulps
tation. If desired, however, the washing may be 35 shall
from the cleaning steps (middlings) as ?nished
carried further to give a. ?nal pulpfor ?otation
concentrates. It will be readily apparent to those
practically free of dissolved lime and having a
skilled in the art that the middlings may be re-_
pH of 9 to 10. Subsequent addition of a caustic
, treated by conventional methods in continuous
, alkali to the lime conditioned and washed pulp to
establish the desired pH for ?otation together 40 ?otation operations to yield an even higher grade
concentrate without departing from the spirit of
with a lignin sulphonate and a fatty acid or soap
the invention.
'
collector enables ?otation of the calcium-ac
The invention will be further illustrated, but is
tivated silica and retardation of the iron oxides.
not intended to be limited by the following ex
‘It will be apparent to those skilled in the art»
' amples of ' practice:
that soft water free of lime or magnesia salts is
not obligatory in the practice of this invention.
Emamnle Z
Some lime or magnesia salts ‘in the ?otation pulp
A sample of calcareous red iron ore was ob
are permissible, and, in fact, are advantageous
tained from an operating mine in the Birming»
in that they insure complete activation of the
50? ham district, Alabama. The ore was typical of
siliceous constituents to ?otation.
.
~ The anion-active collecting agents which we
, havefound suitable for ?otation of the activated
siliceous gangue materials from iron oxides in
clude the higher fatty acids such as oleic' acid or
the district and ‘contained hematite associated
with a gangue composed predominately of quartz
and calcite together with minor quantities of
accessory calcareous and siliceous materials in
cluding shale and ferruginous clay. A head an
. red oil, the puri?ed or crude sodium oleates, fish 55 alysis gave 86.2 percent Fe, 10.6- percent 09.0,
oil fatty acids, ?sh oil soam, and various crude
and puri?ed talloels and sulfate soaps derived
from sulfate paper mill black liquors. The tall
oels, which are mixtures of fatty and resin acids,
are relatively inexpensive and are the preferred
collectors in the practice of our invention.
We have discovered that various addition
agents may be advantageously employed to sup- j
plement the crude or puri?ed lignin sulphonates
and 24.6 percent hydrochloric acid insoluble
(hereinafter referred to as “insol."). The sample
was a. typical calcareousv iron ore containing
siliceous gangue naturally activated to soap ?o
tation. Pulps of the ground ore were alkaline
(pH-8.6), and qualitative tests on the water
showed presence of lime salts.
_
V In carrying out the ?otation process according
to this invention, the iron ore or product to be
treated is ?rst ground to proper size for ?ota
tion, if not already of such size, by conventional
addition agents which we have‘ employed and
methods.
The ?neness of grind may vary from
found useful include the metaphosphates; the
35 mesh to 200 mesh or ?ner depending on the
polyphosphates; sodium silicate; sodium ?uoride;
starches of different botanical origin such as po 70 degree of interlocking of the iron oxides and
in the practice of our invention to enable an
improved separation to be obtained. . The various
gangue constituents in the particular ore; sub
stantially complete liberation of the-iron oxides
and siliceous gangue is essential for a satisfac
yield starch solutions or gels of the ruptured
tory separation by ?otation, and the ?neness of
' granules; hydrolyzed starch products, such'as
British gum or dextrins; and various vegetable 75 grind for a particular ore should be selected ac
tato, vwheat; corn, rice, arrow-root, or tapioca
solubilized byheat and/or chemical treatment to
'
2,403,481
'
8
. cordingly. A limiting size of 100 mesh was chosen
for this ore.
A 250-gram portion of the ore rolls-crushed
to 20 mesh was wet ground to pass 100 mesh using
25 pounds of one-half inch steel rods as the 5
grinding 'media with 250 ml. of tap water in a lab
oratory rod mill.‘ The ground charge was diluted
to a volume of 2.5 liters with additional tap
water to give a pulp containing about 10 percent
solids. The pulp which was ?occulated was then m
dispersed using caustic soda and soda ash equiva»
lent to 2.0 and 1.0 pounds per ton of ore, respec
tively.
,
The dispersed charge was fractionated
percent of the weight of the feed and contained
46.0 percent of the insoluble and only 3.3 percent
or the iron. The untreated slime and cleaner
middlings were su?iciently low. in insoluble to be
considered as iron concentrates. The composite
iron concentrates from the test represent a recov
cry of 96.7 percent of the iron in the feed and
assayed 45.9 percent iron, 6.1 percent lime, and
16.9 percent insoluble.
The results of the recorded test were about
average of those obtained on deslimed charges of
the calcareous red iron ore ground in alpebble
mill, iron ball mill, or iron rod mill to pass v65,
by sedimentation and decantation to remove the
100, or 200 mesh, respectively. Good ?otation
bulk of the slime ?ner than 20 microns. The 15 of the activated quartz and granular silicates was
granular portion, substantially free of slime and
achieved in the tests by using from i. to 2 pounds
coarser than 20 microns, was repulped with ad
per ton of an anionic collecting agent, such as
ditional tap water and transferred to a small
oleic acid, sodium oleate, ?sh oil fatty acid, ?sh
mechanical ?otation cell of standard design.
oil soap, or a crude or puri?ed talloel or sulfate
Su?lcient tap water was added to give a pulp for 20 soap from sulfate paper mill black liquors, to=
?otation containing ‘about 20 percent solids.
gether with sufficient caustic alkali to give a pulp
Flotation of the naturally activated silica was
pH of about 11 and from 1 to 4 pounds per ton
effected from a caustic alkaline pulp using talloel
of a crude or puri?ed lignon sulphonate to retard
as the collector, and Goulac, a commercial dehy
the iron oxides. Sodium hydroxide, potassium
drated sul?te liquid product marketed by Amer 25 hydroxide, caustic soda (commercial lye), and
combinations of hydrated lime and soda ash to
depressant. The reagent charge expressed in
form caustic soda in the pulp proved equally suit
conventional pounds per ton of ore was as fol
ican Gum Products Company, as the iron oxide
lows:
able for establishing the desired caustic alka=
linity for ?otation.
30
Example II
A 250-gram charge of‘ the calcareous iron ore
'
Conditioner
P
Cleaner
‘
Rougher
\
No. 1
No. 2
was ground to pass 100 mesh as in Example I.
r The ground charge, including slime, was trans
No. 1
No. 2
0. 4
0.5
0.1
2.5
0L 4
0.5
0.1
2.5
0. 4
0.5
0.1
2.5
10.5
10.5
10.5
Caustic soda.
o u]
No. 3
35 ferred to a small mechanical ?otation cell of
- standard design and sui?cient tap water was
added to give a pulp for ?otation containing
about 22 percent solids. Flotation of the silica
from the slime-bearing pulp was e?'ected by the
The substantiallydeslimed pulp was ?rst con 40 following
reagents expressed in conventional
ditioned with the caustic soda (commercial lye)
terms of pounds per ton of ?otation feed:
and Goulac to establish the alkalinity desired
for ?otation and to retard the iron oxides. Talloel
Condi
was chosen for the collector in the test. The pulp
“on”
Cleaner
was conditioned with the talloel as indicated. 45
Air was then allowed to enter the cell and re
sulted in immediate formation of a compact,
heavily mineralized froth of the siliceous mate
rials. The froth was collected for 2.5 minutes,
whereupon ?otation was complete. The rougher
froth was cleaned by re-?cating in the same
cell using tap water with additional caustic soda
Reagent
Rougher
No. No.
1
No. No. No. No. No.
2
'
1
2
3
4
5
Caustic soda
(1011180.....‘.
60
Talloel .... ._
_.
Time, min ..... .Q
Pulp pH _______ _.
to maintain alkalinity, Goulac to retard the re- ~
maining iron oxides, and talloel to insure ?ota~
‘The slime-bearing pulp was conditioned with
tion of the siliceous gangue, in each cleaning 65' caustic soda (commercial lye) and Goulac. Tall
Q6]. was then added and the pulp again brie?y Y
step. ‘The ?nal silica rejects, the combined iron
conditioned
as indicated. The rougher froth was
concentrates from the cleaning steps, the rougher
cleaned by re-?oating in the same cell using tap
iron concentrates, and the untreated slime were
water for dilution together with additional caus
dried, weighed, and assayed.
'
‘
tic soda and Goulac.- The rougher and compos
The results of the test follow:
60w ited cleaner iron concentrates and ?nal silica re
d t
Pro uc
Weight,
Assay'per cent‘
Jects were dried, weighed, and analyzed.
Distribution
mm‘ .
The results of the test are as follows: A
perwut
Fe
CaO Insoi. Fe
CaO Insol.
65
mean
Iron concentrates:
Rougher ..... ..
Cleaner ______ _.
Slime
29.1
21.7
(un-
53.0
37.7
1.3
9.7
13.0
19.8
41.6
21.7
4.4
23.7
Amy
16.2
17.3
rm,
‘p8
Fe 0110 Insol.
Distribution,
P" “1"
Fe
CaO Insoi.
\
treated) .... _.
28.6
44.0
8.3
17.8
33.4 26.8
20.5
Oomposite_---_
79.4
45.9
6.1
16.9
96.7
54.9
54.0 70
Siiicarejeots _____ ._
2L6
6.0
10.4
55.0
3.3
45.1
46.0
100.0
37.7
24.9 100.0 100.0
100.0
Composite
feed ....... “h.
Weight£
percen
Q
Rougher .... _.
Cleaner _____ -_
Composite. '
.
8.9
Ironconcentrates:
Elilicareiects .... ..
The ?otation silica rejects accounted for 20.6 75
.
33.151.8
30.04a0
3.3
0.7
\
16.1 41.5
20.1 44.0
10.1
22.8
21.4
29.8‘
'70.047.7
5.1
18.1 02.4
32.0
51.2
30.0 0.1
24.3
40.5
01.1
48.8
100.0aa1
10.0
24.91000 100.0
100.0
7.0
Com osite
iee ..... --
accuser _
..
Flotation oi the silica from the slime-bearing -
pulp rejected 48.8 percent of the silica (insolJ
with a loss oi. only 7.6 percentoi the iron. It is
from the iron oxides.
,
-
vention include the metaphosphates, the poly.
phosphates, sodlum silicate, sodium fluoride, and
various vegetable tannin materials such as que~
bracho extract, oak extract, and Borneo cutch.
The grade of the 'composited iron concentrates
10 recovered from ?otation tests On typical calcare
Example III
In the previously described examples of prac
tice, a lignin sulphonate (Goulac) was employed
to retard the iron oxides during anionic ?otation
oi the naturally activated silica from either de 1.5
slimed or total charges or the ground calcareous
red ore. ‘We shall now consider the results of ?o
tation tests wherein auxiliary addition agents are
employed to supplement the liin'sulphonates
in the practice of our invention.
_
so
ous red ores using several of these auxiliary
agents to supplement commercial lignin sulpha
notes are given below. The red ores were ground
to pass 100 mesh and ?oated by the procedure des
scribed in Example 11.
in the test to supplement the lignin sulphonate
'
Product
Inso].
0.212 46-9
9-1
11-8
0H3} 48-6
8-6
no
at
0.113 49-0
6-8
11-6
a:
3:2} 43-2 12-3 42-5
gtiitt?t‘ixlhusnntnuL 5:2 49-7 so as
91.8
a1
832mm:::::::::::::::
.
Rougher .... .Cleaner ..... ._
45. 4 52. 8
28. 2 37. 0
Com ' ltd"
73.6 46.8
7.6
26.4 6. 7
20. 7
100.0 36. 2
11.0
Silica r9160 :
percent '
4. 2
l3. 0
Fe
0130 111501.
13. 0 60. 3
18. 3 28. 8
17. 3
33. 2
15. 0 95. 1
50. 5
44. 8
51.7
49.5
55.2
24.7 100.0 100 0
100.0
4.9
23. 9
20. 9
Composite
d ..... ._
Fe
m
i8 41-8
5-1
or
as
t3
11
13-9
as
t8 4“ W 12-7
95-0
M
Example IV
The ?otation tests heretofore reported were
made on a typical calcareous iron ore containing
siliceous gangue constituents naturally activated
Fe 080 Insol.
_ Iron concentrates:
Distribution
Recov
Big-nil?!
GaO
spectively, in each step to retard the remaining
iron oxides and yield the ?nal silica reject.
‘
‘
Fe
pounds per ton of feed, respectively. The rough
Assay’per eem
Assay, percent
53:13)‘:
and aid retardation of the iron oxides. The quan 30
titles of caustic soda, causticized potato starch,
S0°iiii‘.‘ttta;iu:::::::::::::
' lignin sulphonate (Goulac), and talloel employed
in the roughing step were 2.8, 2.0, 3.0, and 0.8
5221;551:1311}: """" "
er froth was cleaned 4 times using 0.5 and 0.1 $5
pound per vton of caustic soda and Goulac, re
,
.
Depressant employed
The results of a typical ?otation test on a 250
Efttlfisssasnasna:
gram charge of the calcareous red iron ore
ground to pass 100 mesh in a laboratory r mill
go‘tt?'enséantssnui
‘ and the total charge ?oated by the procedure
described in Example 11 are given below. Potato 25 gé’ii?taaseanztstnai
starch solubilized with caustic soda to rupture
the granules at room temperature and form a
Eititifttitt‘éiannsnu:
starch solution was used as. an auxiliary reagent
Weight
per con
'
the lignin sulphonates in the practice of this in
is applicable to both total and deslimed iron ore
pulps. While we prefer to employ deslimed pulm
in the practice of our invention, desllming is not
.
which have been employed in conjunction with
therefore apparent that our method of ?otation
obligatory for a satisfactory separation of silica
it
In addition to the starches and hydrolyzed
starch products, other useful auxiliary agents
A combination of the lignin sulphonate and
causticized potato starch facilitated retardation
' ofboth the slime and granular iron oxides dur
to soap ?otation. We shall now consider the ap
plication of our method of ?otation to siliceous
iron ores which contain unactivated siliceous ma
terials; the silica in such ores is usually non
?oatable by anionic collectors, but can be ren
dered ?oatable in the practice of our invention
by the use of hydrated lime or metal-salt activat
ing agents.
,
‘A sample of rejects was obtained from an iron
ore washer in the Mesabi range, Minnesota. ,.The
sample as received was substantially‘ ?ner than
48 mesh, and was a" composite of classi?er alldq
ing anionic ?otation of the activated silica. 55 dewatering device over?ows impractical to treat‘
Other cereal and tuber starches, such as corn,
by methods of ?otation heretofore available. The
sample contained hematite as the predominate
iron oxide together with specular hematite and
magnetite. The gangue was mainly quartz with
tions or gels of the ruptured starch granules were
. employed in other tests on the ore to supplement 60 some iron silicate minerals and clayey‘ material.
A head analysis gave 40.9 percent Fe and 33.8
the lignin sulphonates. An optimum quantity of'
’
percent insoluble.
the starches and lignin sulphonate gave results
A 250-gram portion of the washer rejects was
substantially identical to those recorded. The
wet ground to pass 100mesh and deslimed at/20
utility of the starches and hydrolyzed starch prod
microns by sedimentation and decantation using
ucts for retarding iron oxides during anionic ?o
the procedure described in Example I. The gran
tation of activated silica from caustic alkaline
ular portion was transferred to a laboratory me
iron ore pulps is described in a co-pending appli
chanical ?otation cell of standard design and
cation, Serial No. 567,763, ?led December 11, 1944,
diluted with tap water to give a. pulp containing
by Julius Bruce Clemmer and Milton Friel Wil
about 20 percent solids for ?otation. The pulp
liams, Jr. Although the starches and hydrolyzed,
was ?rst conditioned with hydrated lime to estab
starch products are not obligatory in the prac
lish a pulp pH of about 11 and activate the quartz
tice of this invention, they are advantageous ad
and silicate minerals to soap ?otation. The
dition agents and enable an improved retardation
lime-conditioned pulp was subsequently condi
of the iron oxides with reduced quantities of the
75 tioned with soda ash to precipitate the hydrated
lignin sulphonates.
wheat, rice, arrow-root, and tapioca, solubilized
by heat and/or chemical treatment to yield solu
2,403,481
'11
lime remaining in solution as insoluble calcium
purpose of activating the silica to anionic ?ota
tion while retarding ?otation of the iron oxides.
A 250-gram charge of the rejects was ground and
deslimed using the procedure described in Exam
ple I. The granular portion was ?oated in a
mechanical ?otation cell of standard design using
the following reagents, expressed in conventional
pounds per ton of ?otation feed:
carbonate and simultaneously form caustic soda
in the pulp. The resulting pulp, substantially
free of dissolved lime, was then conditioned with
Marathon M, a commercial magnesium lignin
sulphonate marketed by the Marathon Chemical
Company, and talloel, and then subjected to ?ota
tion. The rougher froth was double-cleaned by
re-flotating in the same cell using tap water for
dilution together with additional caustic soda, 10'
l
Marathon M, and talloel in each step to retard
Reagent
the remaining iron oxides and yield a ?nal silica
reject of low iron content. The quantities of
reagents, expressed in conventional terms of
Caustic soda ________ _.
pounds per ton of ?otation feed, employed in the 15 Basie~calcium lignin
test were as follows:
sulphonate . .
.._.__
Talloel ...... __
Conditioner
Reagent-
Rougher
No.
1
No.
2
No.
3
No. ‘
4
No.
1
No
2
20
Hydrated lime...
Soda ash
Caustic soda_-___
Marathon M _
_
4.
_ . _ _ -_
0. 8
_-
1.1
0.3
0. 1
Time, min..
___
2. 5
2. 5
2. 5
2. 5
4.0
4.0
3.0
_ __
11.2
11. 1
11.0
11.0
10.8
10.8
10.8
__ _ _
_ _ _ _ _ _
1.1
0. 3
_ _ _
pp
. _ . . _ _
0.
Talloel _ . . _ _ .
1
Cleaner
Rougher
No. 1
No. 2
No 1
No. 2
4. 4
................ __
0. s l
6. 0
________________ -.
0. 4
0. 4
0. 1
0. 1
___ ______ __
Time, min._.___
Pulp pH ............ _.
Cle aner
Conditioner
. 2.5
11. 05
0.6
________ ._
2.5
ll. 0
2.5
' l0. 9
2.5
10. 75
o. a
2.5
10. 8
The composited iron v concentrates recovered
from the roughing and cleaning steps in the test
assayed 58.4 percent Fe and 8.8 percent insol.,
and represented a recovery of 93.6 percent of the
iron in the ?otation iced. The silica rejects as
25 sayed 9.3 percent Fe and 84.8 percent insoluble
and contained 80.6 percent of the silica in the
feed. The calcium salts contained in the com
mercial basic calcium lignin sulphonate employed
The grade and ‘distribution of iron and in
in the test was "sufficient to activate the silica to
soluble in'the test products were as follows:
30 anionic ?otation and the lignin portion retard
the iron oxides. In the practice of our invention,
Product
we prefer, however, to employ supplementary
Assay, per cent Distributiton,
per Gen
Weight
per mm’;
'metal salt activating agents to insure more com
plete activation and ?otation of the siliceous
Fe
Insol.
Fe
Iron concentrates:
35 gangue constituents.
Insol.
,
Example VI
1' 7
Rougber ________ --
49. 7
57. 2
7. 8
67. 7
11. 9
Cleaner _________ -_ »
l7. 7
51. 7
l8. 1
21. 7
9. 8
67. 4
32. 6
55. 8
13. 6
10.5
78. 3
89.4
10. 6
21. 7
78. 3
A 250-gram portion of the Mesabi washer re
jects was ground to pass 100 mesh and deslimed
40 at 20 microns by the procedure. described in Ex
Composite ?ota
ample‘ I. The granular portion was froth ?oated
tion feed ____ .100. 0
42.0
32. 6
100.0
100. 0
in a mechanical cell to reject the silica and recover
an iron enriched product using hydrated lime to
Activation and ?otation of the silica from the
activate the silica, Marathon NS, a commercial
ground and deslimed sample rejected 78.3 per 45 sodium lignin sulphonate marketed by the Mara
cent of the insoluble and enabled recovery of 89.4
thon Chemical Company, to retard the iron ox
percent‘of the iron in concentrates which as
ides, and talloel-as the collector for the activated
sayed 55.8 percent Fe and 10.5 percent insoluble.
silica. The reagent charge, expressed in pounds
Similar results were obtained on the washer _ per ton of ?otation feed, employed in the test
Composite ____ _.
Silica rejects _________ __
rejects using other commercial lignin sulpho 50
was as follows:
nates to retard the iron oxides during anionic
?otation’ of the calcium activated silica from
caustic alkaline pulps. The grade and yield of
iron concentrates from comparative tests with
Conditioner
Reagent
.
several lignin sulphonates using the previously 55
described ?otation procedure are as follows:
Hydrated lime
Caustic soda
Marathon N S-
Iron concentrates
‘
Assay, per cent
Weight,
Rougher
No. 1
122.03%’
Fe
No. 2
No. 3
5. 5
.
1. 5
.
3. 0
Talloel. _ _
Time,
Lignin sulphonate
,
--
‘
0. 8
_-
........ -_- ________ _ _
2. 5
2. 5
a5
a0
Pulp pH ..................... __
.10. 6
11. 0
11. 0
10. 85
60
A roughing treatment sufdced for an adequate
separation of the activated silica from the re
tarded iron oxides. The rougher iron concen
Acid calcium lignin sulpho
trates assayed 57.6 percent Fe and 8.1 percent
at
54. 9
565
Neutral calcium lignin sul
insol., and represented a. recovery of 85.7 percent
phonate __________________ -_
55. 6
Basic calcium lignin sul
of the iron in the feed. The silica rejects rougher
phonate __________________ __
53. 0
froth assayed 16.0 percent Fe and 85.2 percent
Sodium lignin sulphonate___
54. 4
insol., and contained 62.2 percent of the insoluble
in, the ?otation feed.
Example V
70
In the recorded test, it will be noted that good
?otation of the silica was achieved from the iron
A portion of the washer rejects containing un
oxides in the presence of hydrated lime. Supple
activated silica was next ?oated using a solution
mentary
experiments indicated that the ?otation
of a commercial basic-calcium lignin sulphonate
contained about 0.8 pound of dissolved hy
that contained 12.0 percent of 08.0 for the dual 75 pulp
drated lime .per ton of solids in the test. While
per cent
n
e ...................... __
Fe
Insol.
-
i3
we prefer that the ?otation pulp-be substantially
free of dissolved hydrated lime in the practice
of our invention, it is not obligatory that the ?o
tation pulps be completely free 01' hydrated lime
or calcium salts. Some calcium salts in the 110
tatlon pulp a_'e permissible, and, in fact, are ad
vantage'ous in that they insure more complete
_ notation of the silica. in carrying on our inven
id
many variations and modi?cations may be made .
therein without. departing from the spirit of the
invention.
‘What is claimed:
\
'
'
l. A process for beneficiating calcareous iron '
ores containing siliceous gangue materials which
comprises addition to an aqueous pulp of the
conuted ore a quantity of caustic alkali to
establish a pulp pH at least as alkaline as pHlG
tion we prefer that the ?otation pulp contain not
more than 100 parts per 'million of dissolved hy= "lid and a lignin sulphonate,‘ together with an anion
active collecting agent selected from the class
drated lime or calcium salts.
.
consisting of higher fatty acids, resin acids, and
Example VI!
mixtures of fatty and resin acids, and soaps
A 250=gram portion of the washer rejects was
ground and desllmed as previously described. The
granular portion was conditioned with the equiv
slant of 1? pounds per ton of hydrated lime. The
lime-conditioned pulp which had a pH of 12.3
was then washed three times with tap water to
thereof, and then subjecting said pulp to agitaw
tion and aeration whereby siliceous gangue is
heated and bene?ciated iron ore is depressed and
recovered.
2. A process for heneilciating calcareous iron
ores containing siliceous gangue materials which
comprises addition to an aqueous pulp of the
remove the hydrated lime remaining in solution. Y 20 comminuted ore a quantity of caustic alkali to
a The resulting pulp which had a pH of 9.8 was sub
establish a pulp pH at least as alkaline as pH 10
sequently transferred to a laboratory mechanical
an iron oxide depressant selected from the‘ class
?otation cell and diluted with tap water to give
consisting of crude and puri?ed metal salts of
a pulp for ?otation containing about 20 percent
lignin sulphonic acid, crude and puri?ed paper
25
solids. The pulp was conditioned with caustic
mill sul?te liquors. and dehydrated residues
soda, Goulac, and talloel, and then subjected to
thereof, together with an anion active collecting
?otation to ?oat the lime-activated silica from
agent selected from the class consisting of higher
the retarded iron oxides. ,The rougher froth was
fatty acids. resin acids,
ures of fatty acids
triple-cleaned by re-?oating in the same cell us
and resin acids, and soaps thereof, and then
ing tap water for dilution together with caustic 30 subjecting said pulp to agitation and aeration
soda, Goulac, and talloel. The quantities of re
whereby siliceous gangue is ?oated and bene?
agents, expressed in terms of pounds per ton of’
ciated iron ore is depressed and recovered.
?otation feed, employed or the test were as fol
v '3. A process for bene?ciating iron ores con
lows:
’
35 taining siliceous gangue materials which com
prises addition to an aqueous pulp of the com
Conditioner
Reagent
Cleaner
Bougher
No. 1 No. 2
Genetic is..-
2.8
Gnnlnn
4. 3
Tnlloel . _ _
Time,
___________ __
No. 1 No. 2 No. 3
1.1
1. 1
1.1
0. 6-
0. 6
0. 6
0. 1
4.0
0. 1
3.5
0. 1
2.5
l0. 8 10. 75
10. 85
________ __
2.5
0. 9
2.5
Pulp pH ............. _- ll. 1
11. 1
.
5.5
10. 7
minuted ore a quantity of caustic alkali to es
itablish a. pulp at least as alkaline‘ as pH 19
adding thereto a basic-calcium lignin sulphonate
40 together with an anion active collecting agent
selected from the class consisting of higher fatty
acids, resin acids, mixtures of fatty and resin
acids, and soaps thereof. and then subjecting said
pulp to agitation and aeration whereby siliceous
The grade and distribution of iron and insoluble 45 gangue is ?oated and fbene?ciated iron ore is
depressed and recovered.
>
1i. A process for bene?ciating iron ores con
taining siliceous gangue materials which com
prises conditioning an aqueous pulp of the com
Product
Weight, May’ New
' percent '
50 minuted ore in the presence of su?icient hydrated
per cent
lime to yield a pulp with a pH of at least 19 and
'
Fe
Insol.
Fe
Insol. .
containingnot more than 100 parts per million
of dissolved hydrated lime, adding thereto a
Iron concentrates:
Rougher ........ __
38. 8
55. 6
9. 9
51. 5
ll.
li
sulphonate and subjecting said pulp to
Cleaner ......... . _
33. 4
54. 0
l4. 6
‘l3. 0
15.
55 agitation and aeration in the presence of an
Composite .... .72. 2
54. 8
l2. 3
94. 5
27.
in the test products were as follows:
-
Silica rejects ........ .-
27. 8
-
8. 2
Distribution
85. 4
5. 5
72.
anion active collecting agent selected from the
class consisting of higher fatty acids, resin acids,
Composite iiote
mixtures of fatty and resin acids, and soaps
thereof, whereby siliceous gangue is ?oated and
:bene?ciated iron ore is depressed and recovered.
Activation and ?otation of the silica from the 60 5. A process for bene?ciating iron ores con
ground and deslimed sample rejected 72.8 per‘
taining siliceous gangue materials which com
cent of the silica and enabled recovery of 94.5
prises conditioning an aqueous pulp of the
percent of the iron in concentrates which assayed
comminuted ore, in the presence of su?lcient
.
tion iced .... --
100. 0
41. 8
3?. B
100. 0
00.0
54.8 percent Fe and 12.3 percent insoluble.
’
hydrated lime to ‘yield a pulp with a pH of at Y
The results of the previously described ?ota 65 lease 11, thereafter washing the conditioned pulp
tion tests are typical of those we obtained on a
with fresh water to yield a pulp containing not
variety of ‘calcareous and siliceous iron ores us
more than .100 parts per million of hydrated lime
ing various crude and puri?ed lignin sulphonates
remaining in solution, adding thereto su?lcient I
as the iron oxide depressants while ?oating acti
caustic alkali to establish a pulp at least as alka
vated siliceous. gangue constituents from caustic 70 line
as pHlO, and a lignin sulphonate, thereafter
alkaline iron ore pulps Owith oleic acid, sodium
oleate, talloel, sulfate soap, or similar anionic col
lecting agents. While we have disclosed the pre
subjecting said pulp to agitation and aeration in
the presence of an anion active collecting agent
selected from the class consisting of higher fatty
ferred embodiments of our invention, it will be
readily apparent to those skilled in the art that 75 acids, resin acids, mixtures‘ of fatty and resin
2,403,481. v I
.
16
acids, and soaps thereof, whereb'y siliceous
7. A process for bene?ciating iron ores con
gangue is ?oated and bene?ciated iron ore is
depressed and recovered.
,
taining siliceous gangue materials which com
prises addition to an aqueous pulp of the com
minuted ore a quantity of caustic alkali to es
tablish a pulp at least as alkaline as pH 10, and
a soluble compound of an inorganic anion com
.
6. A process of bene?ciating iron ores con
taining siliceous gangue materials which com?’
prises conditioning an aqueous pulp of the com
minuted ore in the presence of su?icient hy
bined with a. polyvalent metal selected from the
drated lime to yield a pulp with a pH of at least
class consisting of calcium, magnesium, stron
11, adding thereto soda ash to precipitate the
dissolved hydrated'lime and yield a pulp con 10 tium, barium, and lead, together with a lignin
sulphonate and thereafter subject said pulp to
taining not more than 100 parts per million of
agitation and aeration in the presence of an
hydrated lime remaining in solution, and adding
‘thereto a lignin sulphonate and thereafter sub
jecting said pulp toiagitation and aeration in the
' anion active collecting agent selected from the
class consisting of higher fatty acids, resin acids,
_ presence of‘ an anion active collecting agent 15 mixtures of fatty and resin acids, and soaps
thereof, whereby siliceous gangue is ?oated and
selected‘ from the class consisting of higher fatty
acids, resin acids, mixtures of fatty and resin
acids, resin acids, mixtures of fatty and resin ac
ids. and soaps thereof, whereby siliceous gamma
is ?oated and bene?ciated iron ore is depressed 2o
and recovered.
1
bene?clated iron ore is depressed and recovered.
JULIUS BRUCE CLEMMER.
CARL RAMIPACEK.
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