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Patented Sept. 17, 1946
2,401,651
UNITED s'rArEs PATENT OFFICE‘
2,407,651
CONCENTRATING FLUORSPAR BY FROTH
'
FLOTATION
Julius‘ Bruce Clemmer and Ballard H. Clemmons,
Tuscaloosa, Ala., assignors to the United States
of America, as represented by the Secretary of
Interior
No Drawing. Application November 1, 1944,
Serial No. 561,458
18 Claims. (Cl. 209-166)
(Granted under the act of March 3, i883,
as amended April so, 1928; 370 o. G. 757)
2
The invention described herein may be manu
factured and used by or for the Government of
Fluorspar deposits occur in both igneous and sedi
the United States for governmental purposes
or shear zones; as horizontal or bedding replace
ment deposits in sedimentary rocks; or as in
without the payment to us of any royalty thereon .
in accordance with the provisions of the act of
April 30, 1928 (Ch. 460, 45 Stat. L. 467).
mentary rocks as veins following faults, ?ssures,
crustations in vugs and caves. Sizeable deposits
of ?uorspar are known in our Western States
This invention relates to an improved process
including California, Arizona, New Mexico, Ne
for the concentration of ?uorspar ores by froth
vada, Texas, and Colorado. The vein and bedded
?otation; more particularly it relates to the froth
deposits of the Il1inois~Kentucky district are re
?otation of ?uorspar of a high degree of pur 10 puted to be the largest in the world. It is to ores
ity from pulps containing calcite or barite.
from these deposits that particular attention was
An object of the invention is to provide a froth
given in developing the improved process of froth
?otation process for the concentration of natural
?otation hereinafter described, although ores
?uorspar ores and products for recovery of ?uor
from other localities can successfully be bene
spar. A further object is to provide an improved 15 ?ciated by our invention.
?otation process for separating ?uorspar from
The gangue minerals commonly found asso
calcareous gangue materials such as calcite or
ciated with ?uorspar in commercial deposits are
limestone. A still further object is to provide a
quartz, calcite, and barite. Other accessory min
?otation process for recovering ?uorspar of a
erals may include various sul?des such as galena,
high degree of purity from ores containing barite. 20 sphalerite, pyrite, or chalcopyrite, or oxidized lead
Still other objects include the development of an
and zinc minerals such as cerussite and smith
improved ?otation process which will have greater
sonite. Common gangue constituents of ?uor
selectivity in separating ?uorspar from associ
ated sul?de or non-sul?de gangue materials and
spar ores are limestone and clay and many ores
also contain shale and sandstone. Ores from dif
thereby effect greater operating economies. 25 ferent deposits, or from different portions of the
‘ ,Other objects, purposes, and advantages of the
‘invention will hereinafter more fully appear or
same deposit, may show considerable variation
both as regard mineral association and relative
will be understood from the detailed description
proportions of ?uorspar and other minerals. In
of its practice.
the Illinois-Kentucky ?uorspar district, for ex
Fluorspar has wide and varied application in 30 ample, the ore from a particular deposit may be
the chemical, ceramic, and metallurgical indus
devoid of barite whereas that from an adjacent
tries. Its uses range from a source of ?uorine and
hydro?uoric acid in chemical. processes to that of
a ?uxing material in steel making. Commercial
deposit may contain 10 percent or more of barite.
Similarly, the galena or sphalerite contents‘may
also show considerable variation. Ore from a
?uorspar, commonly referred to as "Spar," is
35 particular mine location may contain minute
furnished to meet a number of varying speci?ca
quantities of galena or sphalerite whereas ore
tions as to size and analysis. The ?uorspar con
from another part of the mine often contains
tent of the commercial products ranges from
sufficient galena or sphalerite to justify their re
a minimum of 85 percent in the case of “gravel
covery as valuable by-products in ?uorspar mill
spar” for steel making to a minimum of 97 per 40 ing. The lime and silica contents of ?uorspar
cent ?uorspar in “acid grade” material for chem
ores may likewise show considerable variation.
ical processing. The speci?cations as to allow
Uniform deposits of ?uorspar are an exception
able impurities vary with the industry, but all
rather than the rule, and milling methods must
demand a ?uorspar product relatively free of
be sufficiently ?exible to permit treatment of a
silica, calcium carbonate, barite, and sul?des such 45 variety of ores of different grades and mineral
as galena, sphalerite, or pyrite. Flourspar ores as
association. An important object of this inven
mined seldom meet market speci?cations, either
tion is to provide for the?rst time a ?otation
as regard ?uorspar content or freedom from im
purities, and suitable methods of concentration,
method applicable to a variety of ores of different
grades and mineral association for recovery of
such as froth ?otation, must therefore be em 50 the ?uorspar from associated gangue materials.
ployed to recover commercial products from the
As a result of extended research and experi
low grade or contaminated ores.
mentation, we have discovered that the lignin
Geographically, ?uorspar is widely distributed
sulphonates used in conjunction with an addition
in minute quantities, but deposits of commercial
agent, such as sodium ?uoride, are effective for
value in the United States are not numerous. 65 the retardation of barite and siliceous or cal
2,407,651
- 3
4
careous gangue materials in the froth ?otation of
ligneous materials. The precipitated lignin sul
phonate may be further puri?ed by dissolution
?uorspar by-fatty acid or soap collecting agents.
The combination of these reagents also enables
retardation of sul?de minerals such as galena.
sphalerite, or pyrite when ?oating ?uorspar from
pulps containing the minerals as gangue. Oxi
dized ore minerals and iron oxides, or other non
sul?de gangue minerals such as celestite, may also
be retarded in ?uorspar ?otation by these de
pressants. Fluorspar concentrates of high purity
have been recovered from a wide variety of
?uorspar ores and products even when containing
sul?de and non-sul?de gangue materials, by using
lignin sulphonates and addition agents to selec
tively retard the gangue materials while floating
the ?uorspar with fatty acid collecting agents.
The lignin sulphonates which we prefer to
and re-precipitation, by dialysis, or other
methods. The puri?ed sulphonates are ordinarily
marketed as the powdered forms but solutions
containing from 15 to 50 percent of the lignin
sulphonate are also available. Various of the
commercially available puri?ed lignin sulphonates
including the calcium, magnesium, sodium,
barium, aluminum, zinc and copper salts have
been tested and found satisfactory as gangue
depressants in our method of ?uorspar ?otation
when used in conjunction with an addition agent
such as sodium ?uoride. The calcium, magne
sium, and sodium sulphonate are less expensive
than the heavy metal salts and are preferred. '
The purified sulphonates are somewhat more
effective than the crude or unpuri?ed compounds
utilize as gangue depressants ‘in this invention
but all of the liquid or powdered forms of either
are present in and may be derived from the by
product of the sul?te process of paper making 20 the crude or puri?ed sul?te liquor materials may
be used in our method of ?uorspar ?otation and
commonly known as “sul?te liquor.” These
the ultimate choice of the particular material
liquors separated as waste from the cellulose pulp
employed will largely depend upon economic
contain soluble salts of the lignin sulphonic acids
factors.
and other non-ligneous organic substances, such
The lignin sulphonates are recognized as being
as hydrolyzed carbohydrates. resulting from de 25
multi-basic in character and contain acidic groups
composition of the wood by the acid solutions used
of varying strength ranging from the strong sul
in the pulping process. In the sul?te process, the
phonic to the weak phenolic group, and some may
lignin in the wood is dissolved by digesting the
wood chips with an acid solution of calcium,
magnesium, or sodium sul?te at an elevated tem
also contain minor amounts of carboxyl groups.
30 The sulphonic is the dominant acidic group and
the amount depends on the degree of sulphoniza
tion employed in the pulping process to solubilize
the lignin and allow its separation from the cel
ing on the base employed. The sul?te liquors con
lulose. Lignin sulphonates of either higher or
taining the lignin sulphonates and non-ligneous
materials may be used as the gangue depressants 35 lower degree of sulphonation may be made by re
treatment of the sul?te liquors to meet speci?c
in our method of ?uorspar ?otation or the crude
requirements. The lignin sulphonic acids readily
sul?te liquors may be puri?ed by known methods
react with metal salts to form the corresponding
to reject the non-ligneous substances and recover
sulphonates. These salts may be made from the
a substantially puri?ed lignin sulphonate which
may be employed to retard the gangue.
40 calcium salt by double decomposition reactions
or from a solution of the free sulphonic acid.
The crude or whole sul?te liquor recovered
The type of salt formed depends on the conditions
from the sul?te pulping process and containing
perature wherebythe lignin forms soluble calcium,
magnesium, or sodium lignin sulphonates depend
the lignin sulphonates and non-ligneous organic
established for the reaction.
In the normal or
so-called acid salt at pH of about 5 in aqueous
solution only the strong sulphonic groups are in
their salt form; in the so-called neutral salts at
about pH 7.0, the sulphonic and some of the
phenolic groups are in salt form; and in the so
stantially dehydrated. The liquid and powdered
called basic salts at pH 11 and above all the acidic
forms have been used interchangeably in our 50 groups may be regarded as present in their salt
form. The basic calcium salts are insoluble in
?otation and, based on their respective content of
aqueous solutions at high pH but disperse or dis
lignin sulphonate, are equally effective for re
tardation of gangue constituents. Comparative
solve under neutral or acid conditions. Other
wise all lignin sulphonates of normal degree of
?otation tests using the calcium, magnesium, and‘
sodium base sul?te liquors or dehydration resi 55 sulphonation are soluble inv water under all pH
dues gave substantially equivalent results. The
conditions to give colloidal solutions or dispersions
non-ligneous materials present in the liquid or
which we may use as gangue depressants in con
dehydrated residues appear to be an inactive
junction with addition agents such as sodium
diluent and exerts little or no deleterious effect in
?uoride in our method of ?uorspar ?otation.
the froth ?otation of ?uorspar when using sodium 60 A variety of liquid and powdered forms of
substances, such as hemi-cellulose and various
sugars, may be evaporated to yield a concentrated
liquid or dehydrated residue for marketing. The
liquid forms as marketed contain about 50 per
cent water whereas the powdered forms are sub
?uoride as an addition agent. Pound per pound,
both crude and puri?ed sul?de liquid products
the evaporated crude sul?te liquors or dehydra
are commercially available and have been found
satisfactory gangue depressants in the practice
of this invention. Examples of the sul?te liquor
tion residues are slightly less effective than the
corresponding puri?ed lignin sulphonates rela
tively free of non-ligneous material, but are par
ticularly attractive as gangue depressants in our
method of ?uotation 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
?ed lignin sulphonates. Fractional precipitation
methods using sodium chloride, calcium chloride,
65 materials which we have used successfully in
clude
those
sold
under
the
trade
names
“Bindarene liquid,” “Binderene ?our,” “Goulac,”
“T. D. A.,” "Marathon extracts M, T, NS, TanC,
I SL, DT-31, DT-32, DT-33, DT-34, and DT-35,"
70' and the “Daxads 11, 21, and 23.” Other sul?te
liquor products which have been found accept
able include the crude and puri?ed magnesium
lignin sulphonates, the acid, neutral, and basic
mineral acids, lime water, basic lead acetate, or
calcium lignin sulphonates, and sodium, copper,
organic bases may be employed to recover the
lignin, sulphonate and reject the bulk of the non 75 zinc, aluminum, and barium lignin sulphonates.
5
9,407,651
As far as we are aware the lignin sulphonates
singly or together with addition agents such as
sodium ?uoride have not heretofore been em
ployed for the retardation of gangue constitu
ents in the ?otation of ?uorspar ores. In our
method of froth ?otation of ?uorspar, retarda
tion of the calcite and barite or other gangue
constituents is sought and the quantities of lignin
sulphonate employed must be su?icient to re
.
6
. _
tively freeof soluble salts or slime gangue con
stituents. We prefer to use addition agents such
as sodium ?uoride in conjunction with the lignin
sulphonates for the ?otation of ?uorspar from
all ?uorspar ores. Less collector is required and
?otation of the ?uorspar is more rapid and com
plete.
Sodium ?uoride was the preferred addition'
agent used in conjunction with the crude or
tard these constituents. The quantity of lignin 10 puri?ed lignin sulphonates. Ammonium and
potassium ?uoride were found equally effective
sulphonate required varies with di?erent ores
and may be as little as 0.25 to as much as 5
pounds or more per ton of ore; the optimum
but was less attractive due to their higher cost.
must be determined by trial.
The mechanism of the retarding action of the
lignin sulphonates on gangue minerals in our 15
method of ?uorspar ?otation has not been de?
nitely determined and this invention is not lim
were also satisfactory but had no particular ad
Aluminum ?uoride and sodium silico~?uoride
vantage over sodium ?uoride and were some
what less soluble. Hydro?uoric and hydro?uo
silico acids may also be used if desired. Our
tests indicate that any inorganic ?uorine-bear
lIlg compound which ionizes in aqueous solution
ited to any theory of action. It seems probable
however, that an important effect of the sul
to yield the ?uoride ion may be used as addition
phonates is to coat the surfaces of the gangue 20 agents in our method of ?otation.
particles so that they present water-avid sur
"Addition agents, other than the ?uorides,
faces which prevents their attachment to the
which we have used in conjunction with the.
bubbles in froth ?otation. The lignin sulphonate
lignin sulphonates to obtain more effective re
coating on the gangue may be induced as a re
tardation of the gangue in ?uorspar ?otation in
sult of either chemical reaction or adsorption to 25 clude sodium sul?de, sodium sul?te and hydro
satiate the surfaces, and this coating prevents
sul?te, sodium cyanide, potassium dichromate.
or greatly inhibits formation of collector coat
ammonium acetate, potassium ferro and ferri
ings which normally would, have formed to
cyanides, sodium citrate, sodium meta and per
render the particles ?oatable. It may be fur
borates,
borax, soda ash, caustic soda, and so
30
ther assumed that ?uorspar particles in the pulp
dium silicate. These reagents are less effective
exhibit ‘much less tendency than the gangue
than the ?uorides but may be advantageously
particles to become coated by the lignin sul
employed on ?uorspar ores to yield an improved
phonates, and, as a consequence, the unsatiated
separation. These reagents serve a multi-fold
?uorspar surfaces become collector-coated and
purpose and assist in ?otation by complexing or
35
are thus rendered ?oatable. J-udicious use of
precipitating soluble salts in the pulp, establish
the lignin sulphonates thus enables selective
the optimum pH for ?otation, or aid in proper
retardation of the gangue in ?uorspar ?otation.
dispersion of slime gangue constituents. Soda
The bene?cial effect of addition agents such
ash, caustic soda, sodium cyanide, and sodium
as sodium ?uoride in the ?otation of ?uorspar
silicate are particularly advantageous as auxil
when using the lignin sulphonates as gangue 40
iary
pH modi?ers, pulp conditioners, and slime
depressants was apparent in the testing of a
dispersants in conjunction with an inorganic
variety of ores containing barite or calcareous
?uoride in our method of ?otation.
gangue materials. Use of the ?uorides enabled
our method of ?otation we have found that
more rapid and complete ?otation of the ?uor 45 theInpulp
should be dispersed. The lignin sul
spar and more e?ective retardation of the gangue
phonates and the ?uoride addition agents which
constituents. The mechanism by which the
we employ in our method of ?otation serve the
?uorides accomplish these bene?cial effects is
two-fold
purpose of dispersing the pulp and
not de?nitely known and no limitation to any
retarding the gangue materials. Supplemen
particular theory of action is intended in this
tary dispersing agents are seldom required as
patent. It seems likely however that one of the
suf?cient lignin sulphonate and soluble ?uoride
important functions of the ?uoride is to com
to depress the gangue constituents in ?uorspar
plex or precipitate soluble salts in the pulp
?otation adequately disperses the ore pulp.
which would otherwise impair selectivity of the
Supplementary slime dispersing agents, such as
separation. The ?uorides are effective slime
silicate, may be advantageously used on
dispersants and may aid ?otation by assisting 55 sodium
?uorspar ores containing large amounts of clay.
in the proper dispersion of the pulp. The com
Various organic dispersants including the tannin
bined effect of complexing soluble salts and dis
extracts, such as quebracho, chestnut, oak, or
persion of the slime may possibly serve to clean
Borneo
cutch, and the dextrins, starches, and
the surfaces of the ?uorspar particles to make
gums may also be used to supplement the lignin
them more readily ?oatable by the fatty acid 60 sulphonates and enable reduced quantities to
collectors. Similar cleaning of the gangue
be employed. The tannin extracts are particu
particles renders them more susceptible to
larly helpful on those ores containing large quan
retardation by the lignin sulphonates. These
titles of calcite as they assist in the retardation
factors may be effective in varying degree on
of this contaminant. The quantity of tannin
different ores depending upon the soluble salts 65 used in conjunction with the lignin sulphonate
present and the relative proportions and surface
must be carefully controlled as an excess tends
purity of the ?uorspar and gangue minerals. We
to retard the ?uorspar.
have discovered that the ?uorides are particu
We have achieved good ?otation of ?uorspar
larly advantageous and their bene?cial effect is
more marked when treating ores containing sol 70 from both neutral and moderately alkaline pulps
by the practice of this invention. Precise con
uble salts or large amounts of calcite or barite.
trol
of the pH of the pulp is not essential for
The need for the ?uorides is less apparent and
an effective separation but we‘ prefer that the
they may be omitted if desired, in the ?otation
of ?uorspar from the highly siliceous ores rela 75 pH be maintained in the range 8 to 10.0. The
frothing proclivities of the fatty acid and soap
2,407,651
7
sulting from the cleaning operations may be re
jected as waste or returned to the preceding ?o
tation step of other convenient points in the
pulps of pH 11 or more should be avoided as the
?otation or grinding circuit for retreatment.
voluminous froths are di?icult to control. A pulp
The practice of this invention is not limited to
pH'of 8 to 10 gave compact, heavily mineralized 5
any particular order of addition of the separate
?uorspar froths on a variety of ?uorspar ores
reagents. We prefer however to properly condi
containing barite and siliceous or calcareous
tion the ore pulp with the lignin sulphonate and
gangue materials. We have found in many cases
sodium ?uoride, or other addition agents, before
that the combination of sodium ?uoride and a
lignin sulphonate' gave a pulp of suitable pH 10 adding the ?uorspar collecting agent. ,The de
pressants and pH modifying agents, singly or to
without the addition of any other pH modifying
gether, may be added to the grinding step if de
agent. A pulp of too high pH may be corrected
sired. Our tests indicate that moderate condi
by judicious addition of an inorganic acid to
tioning of the pulp with the depressants ensures
lower the pH within the optimum range and,
conversely, a pulp of too low pH may be corrected 15 maximum retardation of the gangue constitu
collecting agents increase progressively with in
crease in pH of the pulp and strongly alkaline
by addition of a proper amount of an alkaline
reagent such as soda ash, caustic soda, or sodium
ents. Likewise, moderate conditioning with the
silicate. The pH modifying agent may be added
to the pulp at any time before completion of
the ?uorspar.
simultaneously with the lignin sulphonate and
tion, and the proper quantities are best deter
sodium ?uoride.
The fatty acid and soap collecting agents have
been found suitable for ?otation of the ?uorspar
in the practice of this invention. The collectors 25
case. We have found the invention applicable
to a wide variety of ?uorspar ores containing
collecting agent ensures maximum collection of
'
The proportions of the several reagents used in
the ?otation, but we prefer to add it prior to or 20 this invention are subject to considerable varia
mined by experimentation for any particular
barite and siliceous or calcareous gangue ma
a variety of ?uorspar ores containing barite and
terials. Extensive ?otation experiments on ?uor
spar ores from domestic and foreign deposits
calcareous or siliceous gangue constituents in- ~
have demonstrated that the invention is par
which have been used in the ?otation testing of
ticularly advantageous in that it enables recovery
?sh oil soap, ?sh liver oil fatty acids, and tallv 30 of high-grade ?uorspar concentrates from ores
clude crude and puri?ed oleic acid, sodium oleate,
oil. Saponi?ed tall oil and sulfate soap or skim
mings derived from sulfate paper mill black liq
ors may also be used provided the quantities are
which heretofore had been difficult or impossible
to treat by known methods. A proper balance of
the lignin sulphonate and sodium or other soluble
?uoride effectively retards the gangue and en
carefully controlled. The crude tall oil and sul
fate soap products are violent frothers and an 35 ables rapid and complete ?otation of the ?uor
spar with moderate quantities of fatty acid' col
excess should be avoided.
lecting agents. Excess of collecting agent or de
In carrying out the ?otation process according
?ciency of the depressants results in an inferior
to this invention, the ?uorspar ore or product
separation and the proper quantities must be de
to be treated is ground to proper size for ?otation,
if not already of such size, by conventional meth 40 termined by trial. Moderate variation of the col
lector and depressant reagents is permissible on
ods. The ?neness of the grind may vary from
20 to 200 mesh or ?ner depending on the locking
many ores however.
The wider latitude in re
characteristics of the particular material; sub
stantially complete liberation of the ?uorspar
agent control and more effective retardation of
gangue constituents accomplished by this inven
selected accordingly.
heretofore difficult to treat.
from the gangue is essential for a satisfactory 45 tion thereby effect greater operating economies
vand facilitate recovery of ?uorspar from ores
separation, and the ?neness of grind should be
The ground material in
_
~
This invention is applicable to ?uorspar ores
the form of a pulp is then subjected to froth
and products containing associated sul?de min
?otation to recover the ?uorspar and reject the
gangue materials in the following manner: The 50 erals such as galena or sphalerite. Those ores
containing sufficient sul?de minerals to warrant
pulped material is conditioned with a sul?te
their economic recovery may best be treated by
liquor material containing lignin sulphonate; an
customary sul?de ?otation methods to ?rst re
addition agent such as sodium ?uoride; and a
cover the sul?des and the resulting tailings may
fatty acid collector agent such as oleic acid. Also
if desired a pH modifying agent and slime dis 55 then be retreated by this invention to recover
the ?uorspar and reject the gangue. We have
persant agent may be used. The conditioned
found that the reagents customarily used for
the ?otation of sul?de minerals do not interfere
with the subsequent ?otation of ?uorspar by our
?uorspar froth and a tailings product essentially
free of ?uorspar and containing the gangue ma 60 method. The lignin sulphonates adequately re
tard the remaining sul?des as well as barite,
terials. The froth product may contain some
calcite, or other gangue materials and permits
quartz calcite, barite, or other gangue materials
recovery of high-grade ?uorspar concentrates
collected with the ?uorspar in the initial froth
essentially free of these impurities. Met'al salts
lng operation. The froth is repulped with addi
tional water and re?oated to recover the ?uorspar 65 in the ?uorspar feed carried through from the
sul?de ?otation step, wherein salts such as cop
and reject the remaining gangue materials. One
per or zinc sulfate were employed as activators
or more such cleaning steps suffices to yield ?nal
or depressants, may if desired, be overcome by
?uorspar concentrates of the desired commercial
conditioning the sul?de tailings with sodium cy
grade. Additional reagents, such as a small
quantity of the lignin sulphonate, may be used 70 anide prior to ?otation of the ?uorspar by this
invention. The cyanide complexes or precipi
in the cleaning operations to facilitate rejection
tates the metal salts and thus overcomes any
of the gangue impurities. Also if desired, a froth
deleterious effect these salts may exert in ?uor—
agent such as pine oil or an alcohol may be
spar ?otation. Sodium or other soluble ?uoride
used to promote complete and more rapid ?ota
tion of the ?uorspar. The tailings material re 75 is also effective for overcoming the deleterious
pulp is then froth ?oated by customary mechani
cal or pneumatic methods to yield an enriched
2,407,051
effect of metal salts and complements the action
of sodium cyanide.
Our methodis also effective for recovering acid
grade ?uorspar directly from ore pulps contain
ing substantial quantities of galena, sphalerite.
sentially free of gangue material. The froth was
collected for 2.5 minutes when ?otation was
completed. The rougher froth was triple cleaned
by re?oating in the same cell using tap water ~
or pyrite as gangue constituents. Recovery of 5 and 0.08 pound per ton of lignin sulphonate in
each step to further retard the gangue collected
acid grade- ?uorspar can thus be effected by our
with the ?uorspar in the roughing operation.
method not only when the pulp treated is sub
stantially free of metallic sul?des but also when
The ?nal ?uorspar concentrates represented a
the sul?des are present in material amounts and 10 weight recovery of 55.6 percent, assayed 98.2 per
cent CaFz, 0.1 percent CaCOa, 0.8 percent SiOz,
it is also substantially immaterial whether a
large or small amount of barite or calcite is pres
ent.
Our method is therefore particularly ad
and 0.7 percent'Rzoa, and accounted for a recov
. ery of 98.8 percent of the ?uorspar in the ore.
The high recovery of acid-grade ?uorspar'in'
type found in the Illinois-Kentucky ?uorspar area 15 the test demonstrated the‘utility of the magne
sium lignin sulphonates for ‘retarding siliceous
containing galena and sphalerlte associated with
gangue materials in ?uorspar ?otation. Calcium
the ?uorspar together with extremely variable
or sodium lignin sulphonates gave substantially
amounts of barite calcite, or siliceous gangue con
vantageous for ‘the concentration of ores of the
stituents.
‘
As a result of the practice of this invention,
rapid and essentially complete ?otation of ?uor 20
spar may be effected from ore pulps containing
sul?de and non-sul?de gangue constituents with
the same results. Combinations of sodium ?uo
ride and crude or puri?ed lignin sulphonate were
even more effective and gave a higher recovery
of ?uorspar in concentrates of lower silica con
tent. A duplicate of the recorded test using 1.0
pound of sodium ?uoride per ton in addition to
out the necessity of desliming Desliming of the
?otation feed is not obligatory in our method of 25 the magnesium lignin sulphonate yielded a ?nal
?uorspar concentrate which assayed 98.6 percent
?otation but maybe desirable when treating sur
CaFz, 0.1 percent CaCOa, 0.6 percent S102, and
face ores containing large amounts of clay or
0.5 percent R203, and represented a recovery of
top-soil as contaminants. Less collector is re
97.6 percent of the ?uorspar.
quired and the quantities of the lignin sulpho~
The results of the above mentioned tests were
nates and sodium ?uoride may be materially re
duced when ?oating ?uorspar from deslimed 30 representative of those obtained on other sili
ceous ?uorspar ores from deposits in Arizona,
pulps.
New
Mexico, and Montana. Quartz, feldspar
Anderson et al., in U. S. Patent 2,263,552 pro
and other silicate minerals including clay, and
posed the use of “soft" water, i. e. one having not
associated iron oxides were readily retarded by
to exceed 5 grains of hardness, to obviate neces-V 35 the
lignin sulphonates alone or preferably in
sity of desliming in the ?otation of ?uorspar
‘combination with sodium ?uoride and enabled a
from calcareous gangue materials. We have now
good recovery of the ?uorspar in acid-grade con
discovered that neither desliming nor a soft Wa
centrates by fatty acid or soap collectors.
ter is obligatory in our method of ?uorspar ?ota
tion. Although we prefer to use a soft or only 40
Example II
moderately hard water in ?otation, we have suc
A
tailing
pond
material
from a gravity con
cessfully used water containing as high as 20
grains of hardness without seriously impairing
centration plant operating in the Southern llli
nois ?uorspar district was next examined. The
material consisted of ?uorspar associate-d with
crease with increase in hardness of water em 45 both siliceous and calcareous gangue constitu
ents and assayed 43.1 percent CaFz, 35.4 percent
ployed and operating economy suggests that hard
CaCOz, and 18.2 percent SiO2. Grinding to 48
water be pro-treated by either lime soda or zeo
mesh was su?icient to liberate the ?uorspar for
‘ lite processes prior to use,
The invention will be further illustrated but is 50 recovery of acid grade ?uorspar concentrates.
Numerous ?otation tests were made on this
not intended to be limited by the following exam
sample using various of the commercially avail
ples in which parts and percentage compositions
able liquid and dehydrated residues of crude and
are by weight unless otherwise designated:
puri?ed sul?te waste liquors containing lignin
Example I
sulphonates, with and without sodium ?uoride
A ?uorspar ore consisting essentially of ?uor 55 to retard the gangue while ?oating the ?uorspar
with fatty acid collectors. The lignin sulpho
spar associated with a siliceous gangue composed
nates
while satisfactory, were less effective than
predominately of quartz and clay was obtained
the combination of depressants for retarding cal
from a Colorado deposit. A head analysis gave
cite and limestone and close control of the col
57.8 per cent CaFz, 0.7 percent CaCOz, 29.2 per
cent S102, and 6.2 percent R203. A representa 60 lector was essential for a satisfactory separation.
A typical test using the equivalent of 1.0 pound
tive portion of the ore was wet-ground to 48
per ton of substantially pure magnesium lignin
mesh in a laboratory ball mill and the pulp, in
sulphonate as the depressant and 0.64 pound of
cluding slime, was transferred to a, laboratory
commercial oleic acid per ton as the collecting
mechanical ?otation cell of standard design.
Su?icient tap water was added to give a slurry ()5 agent yielded a froth product in the roughing
operation which assayed 76 percent CaFz, 20
containing about 20 percent solids for ?otation.
percent CaCOz, and 2 percent S102, and con
The pulp was conditioned for 5 minutes with the
tained about 75 percent of the ?uorspar in the
equivalent of 1.0 pound per ton of a magnesium
?otation feed. Triple-cleaning of the rougher
base lignin sulphonic acid and 0.8 pound per
7o
froth
gave a ?nal ‘?uorspar concentrate of acid
ton of red oil (commercial oleic acid) was then
grade assaying 98.0 per cent CaFz, 1.1 percent
added and the pulp conditioned for an additional
CaCOe, and 0.2 percent SiOz, and represented a
2.5 minutes. Air was then allowed to enter the
recovery of 59.3 percent of the ?uorspar. Sub
cell and resulted in an immediate formation of a
stantially equivalent results were obtained with
compact, heavily mineralized ?uorspar froth es
75 calcium and sodium salts of the lignin sulphonic
selectivity of the separation on many ?uorspar
ores. Collector requirements for ?otation in
12'
acids. The crude'lignin products from ‘partial or
complete dehydration of the whole‘ sul?te liquors
while entirely-operativalwere less e?ective than
the puri?ed sulphonates for retarding calcareous
' gangue and closer control of the collector was es
sential 'for separation of ?uorspar in concen
‘V
-
'
Flakes." The pH of the pulp was 11.0 which .
exceeds the optimum desired for ?uorspar ?ota,
tion. Sulfuric acid equivalent to 0.6 pounds per
ton of feed, was then added to reduce the pH
of the pulp to 8.6, a more desirable value. Mas
nesium lignin sulphonate and oleic acid, equiv
alent to 1.0 and 0.32 pounds per ton, were added‘
and the pulp conditioned an additional 5 min
The combination of. a lignin sulphonate and
utes. Air was then admitted to the cell and re
sodium ?uoride was found particularly advan
tageous on the tailing pond material. Less 10 sulted in the immediate formation ‘of a heavily
mineralized ?uorspar froth. The froth was col
collector was required and ?otation of’ the ?uor
lected for‘ 3_minutes when ?otation was com
spar was more rapid" and complete. Uniformly
pleted. The froth assayed 77.1 percent CaFz, and
good results were ‘obtained with either the crude
accounted for 91.5 percent of the ?uorspar-in the
. or puri?ed lignin sulphonates used in conjunc
tion with chemically. .pure or insecticide-grade 15 feed. Triple-cleaning of the rougher froth with
an additional 0.08 pound per ton of ‘magnesium
sodium ?uoride. A proper balance of the collec
lignin sulphonate in each cleaner ‘yielded a ?nal
tor and depressants had to be determined by trial,
?uorspar concentrate of the grade and recove
but moderate variation of the quantities of col
indicated above.
~
lector, sodium ?uoride, or lignin sulphonate was
Soda ash, caustic soda, and sodium silicate
20
were used in conjunction with the combination
‘ A typical test on the tailing ‘pond material
of ?uoride and lignin sulphonate in other tests
ground to 48 mesh in a laboratory ball mill and
?oated by the procedure described in Example I ' on the tailing pond material to establish the
optimum pH for ?otation and to assist in dis~ using 1.0 pound per ton of insecticide-grade so-.
dium ?uoride and sodium lignin sulphonate, re 25 persion of the ore pulp. These reagents were
also helpful as a water conditioner ‘and their
spectively, in conjunction with 0.32 pound per
ton’ of crude oleic acid as the ?uorspar collector a use enabled hard water to be employed in ?ota
tion without impairing selectivity of the sepa
yielded a rougher froth containing 92 percent of
the ?uorspar in the feed and assayed about 75
percent CaF-z, 20 percent CaCOa, and 3 percent 30 Tap water of moderate hardness was used in
all of the ?otation tests previously described. A
SiOa. Triple cleaning of the rougher froth with
number. of tests were also made on the tailing
0.08 pounds per ton of additional lignin sulpho
pond material using a synthetic hard water con
' nate in each step gave a ?nal concentrate which
taining the equivalent of 13 grains of lime and 7
assayed 98.5 percent CaFz, 1.1 percent CaCOs,
and 0.3 percent S102, and represented a recovery 35 grains of magnesia per gallon. A typical test
using the hard water in the grinding, roughing,
of 83.4 percent of the total ?uorspar. .
' and cleaning operations gave a 79.4 percent re
A duplicate of the preceding test using a mag
covery of the ?uorspar in concentrates which
nesium lignin sulphonate gave an 84.2 percent
assayed 98.3 percent CaFz, 0.5 percent CaCOa,
recovery of acid grade spar concentrates. An
other test using calcium lignin sulphonate gave 40 and 0.07 percent SiOs. The ground pulp was
conditioned 5 minutes with 2.0 pounds per ton
77.1 percent recovery of ?uorspar in concen
tratespf acid grade.' Considerable latitude was - of soda ash and 1.0 pound per ton, respectively,
of sodium ?uoride and magnesium lignin sul
apparent in the ?otation testing of the tailing
phonate. Oleic acid equivalent to 0.64 pound per
pond material both in the choice} of the lignin
sulphonate ‘for retardation of the gangue, and 45 ton was added as the ?uorspar collector and the
trates of acid grade.‘
permissible.
-
~
-
.
"
ration.
- in the relative proportions of collector, sodium
?uoride, and lignin sulphonate employed.
'
'
>
pulp conditioned for an additional 5 minutes.
Flotation of the ?uorspar in the roughing opera
tion proceeded in a normal fashion and was com
Comparative ?otation tests using sodium or
plete in 3 minutes. The rougher froth was re
ammonium ?uoride as the addition agents in
conjunction with the various lignin sulphonates 50 pulped with additional hard water and re?oated
twice using 0.5 and 0.2 pounds per ton of the _
gave substantially identical results. Aluminum
magnesium lignin sulphonate in the ?rst and
?uoride and sodium silico-?uoride were also
second cleaner. A third and ?nal ‘cleaning oper
satisfactory vbut were less effective than the
ation using hard water but without ~additional
sodium or ammonium ' salts because of their
lower ‘solubility. Various other addition agents 55 lignin sulphonate yielded acid grade ?uorspar
concentrates of the grade and recovery given
including sodium sul?de, sodium sul?te, sodium
above. Combinations of soda'ash and caustic
meta- and per-borate, ammonium and‘ sodium
soda or soda ash and sodium silicate were used
acetate, potassium'ferro and ferri cyanide, so
in other. tests to pre-condition the hard water
dium ortho, pyro, and metaphosphate, soda ash,
sodium silicate, and caustic soda were used in 60 pulp before ?otation of the ?uorspar by the prac
tice previously described. Good ?otation of the
conjunction with the lignin sulphonates in other
?uorspar was achieved by the various modi?ca
?otation tests on the tailing pond material.
tions provided the pH of the pulp did not exceed
These reagents were somewhat less eifective than
11, and preferably was less than 10.
the ?uorides but enabled an improved separation
of the ?uorspar.
65
Example 111 I
Sodium sul?de was particularly advantageous
The
examples
of
practice described heretofore
and a typical test using this reagent in conjunc
demonstrate the applicability of this invention
tion with magnesium lignin sulphonate gave an
81.0 per cent recovery of ?uorspar in concen
to the recovery of ?uorspar from ores contain-.'
dure employed in the test was as follows: The
ground charge was conditioned 15 minutes with
2.0 pounds per ton of a crude sodium sul?de
practice on an ore ‘containing a substantial
trates which assayed 98.4 percent CaF2, 0.9 per 70 ing siliceous or calcareous gangue constituents.
We shall now describe the results obtained by its
cent CaCOa, and 0.1 percent $102. The proce
amount of barite together with calcite and
quartz. The sample was from a Canadian deposit
product commonly known as “GO-percent Fused 75 and assayed 53.5 percent CaFh, 7.0 percent 1
13
2,407,661
08.003, 0.6 percent S102, and‘ 37.1 percent BaSOu.
Grinding to 65 mesh gave adequate liberation of
the ?uorspar for the production of acid grade
concentrates by this invention.
A representative portion of the Canadian sam
ple was ground to 65 mesh and froth ?oated by
14
and 0.64 pound oi.’ oleic acid as the collector gave
a 67.9 percent recovery of the ?uorspar in concen
trates which assayed 98.4 percent CaFz, 0.6 per;
cent CaCOa, 0.10 percent B84304, and 0.14 per
cent SiOz.
These results are about average of
the procedure described in Example I using 2.0
pounds per ton of sodium ?uoride, 5.0 pounds per
those obtained with various lignin sulphonates
without sodium ?uoride or other addition agents.
0.13 percent SiO2, and 0.05 percent BaSO4, and.
to?uorspar ores containing variable quantities
Numerous ?otation tests have been made on a
ton of an evaporated crude sul?te waste liquor
of ?uorspar ores containing from :none to
containing about 50 percent of magnesium base 10 variety
as much as 70 percent barite using the combina
llignin sulphonic acids, and 0.32 pound per ton
tion of sodium ?uoride and lignin sulphonates to
of crude oleic acid as the collecting agent.
retard the barite. All of the ores responded‘r
Roughing and triple-cleaning of the froth prod
readily to our method of ?otation and yielded
uct yielded a ?nal ?uorspar concentrate which
acid grade ?uorspar concentrates essentially free
assayed 99.2 percent CaFa, 0.4 percent CaCOa, 15 of barite. Our method of ?otation is applicable
represented a recovery of 87.1 percent of the ?uor
of barite for the recovery of- high grade ?uor
spar in the ?otation feed. About 90 percent of
spar
concentrates; conversely, the method may be
the silica and 99 percent of the barite and calcite
used for the puri?cation of barite ores contain
were rejected in the roughing and cleaning treat 20 ing ?uorspar as a contaminant.
ment.
Various of the commercially available liquid
Example IV
and dehydrated residues from crude and puri?ed
sul?te liquors were used in conjunction with
sodium ?uoride in other tests on the Canadian 25
material for retardation of the gangue while
?oating the ?uorspar with fatty acid or soap col
lectors. The relative proportion of the lignin
sulphonates, sodium ?uoride, and collector was
subject to considerable variation and the proper
quantities had to be determined by trial. Mod
erate variation in the quantities of the lignin
sulphonate and sodium ?uoride was permissible
and did not seriously impair selectivity of the
separation. The crude and puri?ed lignin sul 35
phonates were used interchangeably in ?otation
with uniformly good results. The crude products
were slightly less effective than the puri?ed sul
phonates for retarding barite but were particu
larly attractive due to their lower cost.
40
Another test on the Canadian sample using
2.0 pounds per ton sodium ?uoride and 1.0 pound
per ton of substantially pure magnesium lignin
sulphonate residue gave an 86.7 percent recovery
of ?uorspar in acid grade concentrates contain 45
ing 0.15 percent BaSO4. Similar tests using 2.0
A ?uorspar ore from a, Kentucky deposit con
and 5.0 pounds per ton of the magnesium sul
phonate yielded recoveries of 89.4 and 95.3 per
cent of the ?uorspar in concentrates containing
less than 0.1 percent barite. ‘Another series of 50
tests using 0.5, 1.0, 2.0, and 5.0 pounds per ton
of sodium ?uoride, respectively, in conjunction
taining barite, celestite, calcite, and quartz to
gether with minor amounts of galena and sphal
erite as the gangue materials was next exam
ined. A head analysis gave 34.5 percent CaFz,
5.9 percent CaCos, 46.7 percent BaSOr, 7.5 per
cent SrSO4, 3.6 percent SiOz, 0.2 percent Pb, and
0.5 percent Zn. The ?ourspar was intimately as
sociated with the gangue and grinding ‘to 150
mesh was required for liberation.
A representative portion of the ore was ground
to 150 mesh and froth ?oated by the procedure
described in Example I using 2.0 pounds per ton
of sodium ?uoride and magnesium lignin sul
phonate as the depressants and 0.32 pound per
ton of commercial oleic acid as the ?uorspar col
lector. The rougher froth was triple-cleaned with
0.08 pound per ton of the lignin sulphonate in
each step and yielded a ?nal ?uorspar concen
trate which assayed 98.8 percent CaFz, 0.8 per
cent 02.003, 0.07 percent BaSO‘i, 0.10 percent
SrSO4, 0.2 percent SiOz, and only a trace of lead
or zinc. The ?uorspar recovery in the test was
78.3 percent. An excellent rejection of barite,
celestite, calcite, silica, and metallic sul?des was
eiTected by the combination of sodium ?uoride
and the lignin sulphonate.
Example V‘
A ?uorspar ore containing substantial amounts
with 2.0 pounds per ton of the lignin sulphonate
of galena (PbS) and sphalerite (ZnS) in addition
and 0.32 pound per ton of oleic acid as the col
to calcite and silicawas obtained from the Cave
lector gave recoveries of 47.9, 89.2, 89.4, and 79.6 55 in Rock area of the Southern Illinois ?uorspar
percent of the ?uorspar in acid grade concen
district. A head analysis gave 51.4 percent CaFz,
trates containing less than 0.1 percent barite.
10.9 percent CaCOz, 15.5 percent S102, 3.5 per
Calcium and sodium lignin sulphonates in con
cent Pb, and 10.5 percent Zn.
junction with sodium ?uoride gave results en
A portion of the ore was ground to 100 mesh
tirely similar to those obtained by the magnesium
60 and froth ?oated by customary sul?de ?otation
compound. These tests demonstrate that the
methods to recover the galena and sphalerite.
combination of sodium ?uoride and a lignin sul
The sul?de tailing containing 0.2 percent Pb,
phonate is very effective for the retardation of
0.7 percent Zn, and 68.1 percent CaFz was re
barite in ?uorspar ?otation. The separation is
treated by this invention to recover the ?uorspar
highly speci?c and considerable latitude is ap 65 in acid grade concentrates. The tailing from’
parent both in the choice of the lignin sulphonate
sul?de ?otationwas conditioned 5 minutes with
and in the relative proportions of sulphonate and
2.0 pounds per ton of sodium ?uoride and magne
?uoride employed.
sium lignin sulphonate, respectively, and 0.32
Although the combination of sodium ?uoride
pound per ton of oleic acid was then added and
and lignin sulphonate is particularly effective for 70 the pulp conditioned an additional 5 minutes.
retarding barite in ?uorspar ?otation, the lignin
Air was admitted to the cell and the rougher froth
sulphonates may be used alone with good results.
A typical test on the Canadian sample employing
the procedure described in Example I using 2.0
collected for 3 minutes when ?otation of the
?uorspar was completed. The froth product
assayed 86.1 percent CaFz and contained 97.0
pounds per ton of magnesium lignin sulphonate 75 percent
of the ?uorspar in the original sample.
2,407,651
15
The tailings assayed 5.8 percent CaFz and ac
counted for a loss of 1.9 percent of the total
?uorspar.
The ?uorspar rougher froth was re
sample.
16
Triple-cleaning of the rougher froth
using 0.08 pound per ton’ of additional calcium
lignin sulphonate in each vstep yielded a ?nal
?uorspar concentrate which assayed 97.7 percent .
pulped with tap water and re?oated using 0.08
CaFz, 1.5 percent CaCOa, and 0.5 percent SiOz,
pound per ton of the lignin sulphonate to retard
and represented a recovery of 89.1 percent of the
the gangue. Three such cleaning steps yielded
total ?uorspar. A cumulative sizing analysis of
a ?nal ?uorspar concentrate which assayed 98.2
the ?uorspar concentrates showed that 22.8 per
percent CaF2, 0.6 percent CaCOz, 0.3 percent SiOz.
cent of the ?uorspar was coarser than 28 mesh.
0.05 percent Pb, and 0.06 percent Zn, and repre
sented a recovery of 95.0 percent of the total 10. 45.0 percent was coarser than 35 mesh, and 60.1
percent was coarser than 48 mesh.
‘
?uorspar in the original material.
While we have disclosed the presently preferred
The reagent used in the test for ?otation of
embodiment of our invention, it will be readily
the galena and sphalerite included copper sulfate,
apparent to those skilled in the art that many
potassium ethyl and amyl xanthates, phospho
variations and modi?cations may be made therein
cresylic acid, and pine oil. These reagents ex
without departing from the spirit and scope of
hibited no deleterious effect in the subsequent
the invention as de?ned in the appended claims.
?otation of ?uorspar by this invention. The
What is claimed is:
combination of sodium ?uoride and lignin sul
1. The process of concentrating ?uorspar by
phonate adequately retarded the metallic sul?des
remaining in the ?uorspar feed as well as the cal 20 froth ?otation of pulps containing ?uorspar
values, comprising adding to such a pulp sodium
careous and siliceous gangue materials.
Sodium cyanide was used in other tests on the
Cave in Rock sample to complex or precipitate
?uoride, a lignin sulphonate, and a ?uorspar col
lecting agent selected from the class consisting
of fatty acids and soaps, and subjecting said pulp
sul?de tailings prior to ?otation of the ?uorspar 25 to froth ?otation to recover the ?uorspar.
2. The-process of concentrating ?uorspar by
by our method. The combination of sodium cy
froth ?otation of pulps containing ?uorspar
anide and ?uoride was particularly advantageous
values, comprising adding to such a pulp a soluble
for overcoming the deleterious effect of metal
inorganic ?uoride, a lignin sulphonate, and a
salts in ?uorspar/?otation. Cyanide and ?uoride
complement each other and the proper propor 30 ?uorspar collecting agent selected from‘ the class
consisting of fatty acids and soaps, and subject
tions for optimum retardation of the gangue by
ing said pulp to froth ?otation to recover the
the lignin sulphonates may best be determined
the metal salts (i. e.‘ copper and zinc sulfate) in
?uorspar.
3. The process of concentrating ?uorspar by
Various of the commercially available liquid
and dehydrated residues of sul?te liquors have 35 froth ?otation of pulps containing ?uorspar val
by experimentation.
been successfully used in conjunction with sodium
?uoride and sodium cyanide, singly or together,
for the retardation of metallic sul?des and cal
ues, comprising adding to such a pulp a pH mod
ifying agent to establish a pH not to exceed 11,
a soluble inorganic ?uoride, a lignin sulphonate,
and a ?uorspar collecting agent selected from the
careous and siliceous gangue materials in ?uor
spar ?otation of sul?de tailings. No difficulty has 40 class consisting of fatty acids and soaps, and
subjecting said pulp to froth ?otation to recover
been experienced in obtaining'a satisfactory re
the ?uorspar.
covery of acid grade ?uorspar concentrates essen
4. The process of concentrating ?uorspar by
tially free of metallic sul?des.
froth ?otation of pulps containing ?uorspar val
Example VI
ues, comprising adding to the pulp sodium sul
?de, a pH modifying agent to establish a pH not
‘We have discovered that our method of ?ota
to exceed 11, a lignin sulphonate, and a ?uorspar
tion enables the recovery of coarser ?uorspar than
collecting agent selected from the class consist~
was formerly believed, possible by older methods
ing of fatty acids and soaps, and subjecting said
of ?otation. Fluorspar as coarse as 20 mesh has
been satisfactorily separated from calcareous and 50 pulp to froth ?otation to recover the ?uorspar.
5. The process of concentrating ?uorspar by
siliceous gangue constituents by the practice of
froth ?otation of pulps containing ?uorspar val
this invention and it seems likely that even coarser
ues, comprising adding to the pulp a lignin sul
material may be made to yield to our method
phonate, sodium cyanide and an inorganic sol
of ?otation. An illustrative example of the prac
tice of this invention for the recovery of coarse 55 uble ?uoride, and a ?uorspar collecting agent
comprising oleic acid, and subjecting said pulp to
?uorspar will not be given.
'
froth ?otation to recover the ?uorspar.
A jig tailing from an operating plant in the
6. The process of concentrating ?uorspar by
Southern Illinois ?uorspar district was obtained
froth ?otation of pulps containing ?uorspar val
for testing. The material as received was essen
tially ?ner than 6 mesh and assayed 44.6 percent 60 ues, comprising adding to the pulp a metal salt
of lignin sulphonic acid, an inorganic soluble
CaFz, 42.1 percent CaCOa, and 12.1 percent S102.
?uoride,‘ and a ?uorspar collecting agent selected
A representative portion of the sample was care
from the class consisting of fatty acids and soaps,
fully ground to pass 20 mesh and froth ?oated
and subjecting said pulp to froth ?otation to re
to recover the ?uorspar by the procedure described
in Example I. Sodium ?uoride, calcium lignin 65 cover the ?uorspar.
'7. The process of concentrating ?uorspar by
sulphonate, and oleic acid were used in the rough
froth ?otation of pulps containing ?uorspar val—
ing operation in amount equivalent to 2.0, 2.0. and
ues, comprising adding to the pulp a substantially
0.64 pounds per ton respectively. The rougher
dehydrated residue of paper mill'sul?te liquors,
froth, collected for 2.5 minutes, assayed 84.6 per
cent CaFz, 13.3 percent CaCOa, and 1.6 percent 70 an inorganic soluble ?uoride, and a ?uorspar
collecting agent selected from the class consist
‘SiOz, and represented a recovery of 94.2 percent
ing of fatty acids and soaps, and subjecting said
of the ?uorspar. The ?otation tailings assayed
pulp to froth ?otation to recover the ?uorspar.
5.1 percent CaFz, 70.5 percent 021003, and 22.4
8. The process of concentrating ?uorspar by
percent Si02, and contained 84.3 percent of the
calcite and 93.4 percent of the silica in the original 75 froth ?otation of pulps containing ?uorspar val
17
2,407,651
ues, comprising adding to the pulpa paper mill
sul?te liquor, an inorganic soluble ?uoride, and
a ?uorspar collecting agent selected from the class
consisting of fatty acids and soaps, and subjecting
’ said pulp to froth ?otation to recover the ?uor
spar.
9. The process .of concentrating ?uorspar by
froth ‘?otation of pulps containing ?uorspar val
ues, comprising adding to the pulp a lignin sul
18
froth ?otation of deslimed pulps containing ?uor
spar values, comprising adding to the substan
tially deslimed pulp a paper mill ligneous sub
stance selected from the class consisting of sul
?te liquor and dehydrated residues thereof, an
inorganic soluble ?uoride, and a ?uorspar collec
tor selected from the class consisting of fatty
acids and soaps, and subjecting said pulp to froth
?otation to recover the ?uorspar. _
phonate, a tannin extract and a ?uorspar collect 10
13. In a process for the bene?ciation of a
ing agent selected from the class‘ consisting of
?uorspar ore involving the froth ?otation of an
fatty acids and soaps, and subjecting said pulp
aqueous pulp of such an ore in the presence of a
to froth ?otation in the presence of a soluble
fatty acid collector and the recovery in the froth
substance yielding ?uoride ions in solution, to
of a ?uorspar concentrate, the step which, com
recover the ?uorspar.
15 prises carrying out the ?otation in the presence of
10. The process of concentrating ?uorspar by
a soluble substance yielding ?uoride ions in solu
froth ?otation of pulps containing ?uorspar val
tion,
a substance adapted to depress barite in the
ues, comprising adding to the pulp a tannin ex
presence of a soluble ?uoride comprising a lignin
tract, a paper mill ligneous substance selected
from the class consisting of sul?te liquor and de 20 sulphonate. and a substance adapted to depress
calcite comprising a tannin extract, whereby the
hydrated residues thereof, an inorganic soluble
normal
propensity of a tannin extract to ?oat
?uoride, and a ?uorspar collecting agent selected
barite is inhibited by said ?uoride.
from the class consisting of fatty acids and soaps,
14. The process of claim 13, wherein tall oil
and subjecting said pulp to froth ?otation to
is employed as the collector.
recover the ?uorspar.
25
15.
The
process
of
claim
13,
wherein
sodium
11. The process of concentrating ?uorspar by
?uoride is employed as the soluble ?uoride.
froth ?otation of deslimed pulps containing ?uor
16. The process of claim 13, wherein a lignin
spar values, comprising adding to the substan
sulphonate
derived from paper mill sul?te liquor
tially deslimed pulp a paper mill ligneous sub
is employed.
stance selected from the class consisting of sul
The process of claim 13, wherein quebracho
?te liquor and dehydrated residues thereof, a 30 is 17.
employed as the tamiin extract.
?uorspar collecting agent selected from the class
18. The process of claim 13, accompanied by
consisting of fatty acids and soaps, and sub
i an additional treatment to diminish the pulp con
jecting said pulp to froth ?otation in the pres
centration of soluble polyvalent cations.
- ence of a soluble substance yielding ?uoride ions 35
in solution, to recover the ?uorspar.
12. The process of concentrating ?uorspar by
JULIUS BRUCE CLEMMER.
BALLARD H. CLEM'MOI-NS.
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