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Патент USA US3069264

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Dec. 18, 1962
Filed Aug. 23. 1960
2 Sheets-Sheet 1
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C. (am
Dec. 18, 1962
P. E. Qur-:Nl-:Au ETAL
Filed Aug. 23, 1960
2 Sheets-Sheet 2
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L.' coPPERRlcH
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suLFlDE @7_4
FIG. 3
United States Patent Óilice _
Patented Dec;` 1,8,r 1962
preliminary preparation, if necessary, be successfully
converted autogenously and directly to metallic nickel by
the use of an oxygen-rich stream directed' onto' these
materials, at least -a portion of which are; in the molten
state" while providing efficient and effective ¿gas-liquid
solid contact throughout the bath, Le., by induced turbu
P'ái'il Etienne Queneau, Fairfield, Conn., and Louis Se
condo Ranzani, Copper CliiLOntarÍQ‘Canadá, ás'sig'ií
to The International Nickel Company, Inc., New
Filed' Ang.1 2s, 1960, ser. No. 51,438
1-2V Claims.` (014752-282)
lence and controlling oxygen supply and temperature.
Furthermore, another critical deficiency in the prior'art
which prevented continuous liquid phase production ‘of
York; N.~Y_.`,- a corporation of Delaware _
metallic nickel wasî the inability to‘ remove the copper
which is normally »associated with the sullide oresof
nickel; We have also discovered that such’ copper may
The pre-sent invention relates' to an" improved process
for' the smelting` `and reii'ning of nickel- `and copper-con
be continuously separated from nickel by a' major imi
taining sulfide materials for the> direct recovery .of metal
lic nickel or nickel-copper y'alloys therefrom.
Attempts have been made yin the past to produce
provement in the obsolete and' abandoned Orford process.
metallic nickel directly from nickel-‘containing matte.
Thermodynamically and kinetically the react-ions between
process for the autogenous pyrometallurgica'l production
nickel suIlide, oxygen and nickel oxide in- a converter
allow full conversion of nickel mattei to metallic nickel.
It i‘s an object of .the present invention’ to provide a
of nickel or nickel-copper alloys from' nickel-copper
, Another object of thetinvention is to‘ provide a method
Although entirely feasible theoretically, an operable
fo'r producing metallic nickel directly >from nickelfrich
process based on-thesefreactions‘has not heretofore been
sulñde materials such .as mattes by inducing turbulence
Borchers was perhaps the ñrst to attempt to blow
nickel matte' to metal employing «an oxygen blast, but
of the liquid material’ and by impinging processt «gases
ont-he physically and~ cher?iicallyV active surface thereof.
The invention also contemplates providing á novel
because' of` lack of- temperature control- and> improper gas
process for the direct reduction of substantially iron-free
liquid-solid contact he was unsuccessful. We are familiar
with the pioneer work- of Lel'lep on the desulfurizing of
nickel vmatte and' nickel-copper matte` to metallic nickel
nickel matte's _to nickel- metal fanodes.
lThe invention further contemplates providing` novel
methods for separating’copper and cobalt from low iron'
nickel‘ mattes and Áfor reducing `the nickel suh‘ide directly
and nickel-copper alloys, respectively, by blowing in a
converter.-_ Lellep considered surface blowing in «an elîo'r't 30 to metallic nickel.v .
to solve .the insuperable problems which he encountered
It is a further object of the .inventionA to provide' an
when employing submerged tuyere's at the high tempera
autogenous _method *for* eliminating» rock, ironî and sulfur
from nickel'?rich `sullide concentrates such as pe?tlandite
tures he was attempting-to use. Lellep- did not appreci
concentrates »and obtaining nickel metalV low iii copper,
ate, however, the absolute necessity for ellicient gas-solid
cobalt and» precious metals and- .a sulfur dioxide-rich'gas
liquid- contact essential for bath' uniformity »and achieve'
ment of equilibrium» «between- the- several reactants' and
suitable for economic sulfur fixation;Í
the overriding> advantages of using oxygenor cxygenated
air. yInstead he neglected the Vadvantages which are de
Other objects and advantages will‘ ‘become apparent
yfrom 'the following description' taken' in' conjunction with
the; accompanying' drawing in' which :'
rived fromV mechanically' induced bath turbulence andï he
FIGUREV l .shows4 a. longitudinali section through' a".
resorted .to preheatedV air or to extraneous‘heat fromA~ oil, 40
rotary kiln-type- furnace viny which the" auto’g'en-onsV smelt'-`
coalor electric energy, andiinally reliedV upon the' stand
ingf and desulfuriz'ing of` nickel=rich sulfide materials tö
metallic nickel according to the“ hereindes'crïifb‘ed' process
may be: carried out;`
ard `Bes-semer` steel converter for .attempted application
of his process. l Following the-` failu-re- of Lellep, Shott
stall e-tl al. did further work on- improving the bessein’e'r
izing of ínickel-containing mattes to desulfuriz'e` such
AVFIG., 2;,depicts a cross-section' of the saine"> furnace
through line 2_2 of' FIG. l; and'
mattes. They attempted to` accomplish -this"byv forcing
super-heated steam through .the~ molten' matteI employing
submerged tuyerefs but _their process was impractical.
_FIG._‘3 shows'a'diagrammatic!cross-section through a
liquid-liquid extraction column ili'which‘ copper maybe
separated from-nickelV sulfides by the special solventy ex
Shoiïstall` et¿ al. valso fai-led to recognize the necessity- of
proper gas-liquid-fsolid contact and of' the »advantages of
using‘a gasirich in oxygen relative to air.
The Bessemer converter isiernployedinithe'copper` in#
dustry. to convert copper sul?ide- to metallic“copper.n In'
traction` process described hereinafter.'
yAccording to the presentir'ivention,"nickel-containing
to low iron-nickel sullide, the- art- alsoï depends on the’
use' of` the Bessemer concept'_involving`- anV a‘ir-> blast‘be-v
sulfide 'materials such> as* nickelA matte‘ andv cru‘dë nickel
sulfide precipitates‘such as "those‘ obtained by ore'wleachiíig
techniques are smelted autogenously in a‘rota‘rykilriltypë
furnace to a matte, This is'follow‘ed'by’top-blowi g‘thë
matte so obtained'in the same"autogènous,"rotaryfkiln;
low themolten matte level through» tuyeres.V However,
it~«is impossible toA ‘blown nickel sulñde to metallic nickel
riched air directed' down onto the surface‘of‘the'nliolt‘e’n
in this manner. For- this purpose thekairV must be-'highly
bath butI not throughgthe metal from‘below' theliquid
converting nickel-bearing'iron sulfide `in the m'oltenstate
type' furnace using» commercial oxygen' or óxygeii-‘eh-`
preheated or oxygena-ted or fuel must'be Iaçlçledto* main 60 leveh» By-'proper control of Voxygen supply’and'bath’temá
peratnre and by< strong-mechanically-induced“ agitation
tain the» required reactiomtemrïeratures. However, such
modification of the-Bessemer principle _isimpra‘ctical be
cause of resulting. excessive localized-~ temperature rise
and4 refractory attackQ. inadequate> gas-.solid-liquid con
«t'act' with resulting non-uniformity of the bath, fmassive,
of-»the bathwthe molten nickel sulñde is reduced ,to sub-V
stîa‘ritdially" sulfur-free nickel metal. The blowing' and
localized ‘nickeloxide _accumulations and ¿inadequate con~
trol of> op'eratingvariables.
of turbulence is such las _to maintain satisfactory' bath
iluid‘ityï land uniformityA lto permit> rapidj 4nickel> sulfide
Althoughl Lel’lep', Shoffstall ' and' others madel attemptsl
nickel oxide“ reaction and high efficiency of oxygen utiliza.
t-o overcome these"an'd other di'iiicul'ties, they were'un'
able to Ldevelop ’ acomm‘erci’ally operable” process.
We have now’discovered'th-at sulfide' materials rich in
nickel, suclriasßores, concentrates “and lmatter», may, after
mechanical agitation of the bath are controlled'each in-`
dependent of Athe other. ì _Control `of oxygen ,supplyf and
tionl while maintaining the' temperature below,- that at
which’undueirefractory attack isI experienced. „_ Whenßthe
sulfur con't’eiit has ’been decreased Ato" less ¿thanabout 4%'
and'at'which tiinësutlicient oxygen'is normally present
in the bath to oxidize this sulfur, the blast is replaced by
oxygen-impoverished gases, i.e., gases having an oxygen
pletion of the blow, molten metallic nickel is tapped by
tilting the furnace into the position shown by 23 in FIG.
content insufficient to cause visible formation of inter
1 or is optionally withdrawn through taphole 19.
The reduction operation need not be conducted in the
apparatus as specifically shown in FIG. 1 and described
hereinbefore providing the apparatus meets the opera
tional requirements as outlined herein, e.g., it may be
fering amounts of nickel oxide dross on the surface of the
agitated bath. It is critically important that such gases
be at such a high temperature as to permit bath tempera
ture regulation in the 3000° F. to 3200° F. range. A-t
the same time, strong mechanically-induced agitation is
carried out in a top blown converter such as the Kaldo
continued or increased in intensity to maintain e?’icient
and effective gas-solid-liquid contact throughout the bath. 10
Based on tonnage tests, which we have conducted, we
estimate that a single furnace of the above-described
The turbulence in the bath is mandatory to insure bath
uniformity, both physical and chemical, so as to give
quick reaction towards equilibrium, e.g., the nickel oxide
design, with effective inside diameter of about 17 feet,
can produce commercial nickel at the rate of about 500
nickel sulfide reaction. By this «technique sulfur in the
tons per day.
molten bath may be eliminated to less than about 0.05% 15
Nickel matte which is substantially iron-free may be
sulfur, e.g., 0.01% sulfur. It will be understood of course,
blown directly to metallic nickel after copper removal, if
that alternatively standard desulfurization techniques can
necessary, from the molten material as described herein
be employed for final sulfur removal.
after. Precious metals may be removed as described
Agitation of the bath to insure adequate gas-liquid
hereinafter before blowing directly to metallic nickel.
solid contact is obtained by rotating the furnace and by
The sulfide material which has been charged into the
blowing the oxygen-rich gas stream onto the turbulent
furnace is treated by bringing oxygen or oxygen-enriched
molten bath from above the liquid level. It has been
air into direct contact with its surface. This gas, which
found that the blowing operation may be conducted ini
advantageously is initially commercial oxygen, is blown
tially at temperatures not greatly above the melting point
into the furnace above the surface of the molten material.
of the nickel sulfide-containing material and at this stage 25 Necessary bath turbulence is maintained by continuous
advantage is taken of the exothermic heat of reaction
rotation of the furnace at a substantial speed.
to smelt solid feed if desired. However, it is preferred
In the first stage of the blow the temperature of the
to heat the nickel sulfide to a temperature of at least
bath is kept high enough to keep the reacting materials
about 2400° F., avoiding formation of surface oxide,
in a sufficiently fluid state to permit rapid reaction and
under weakly or non-oxidizing conditions prior to blow 30 yet below the temperature at which undue refractory
ing with commercial oxygen. If no melting is to take
penetration or erosion is experienced. For relatively pure
place and molten matte at elevated temperature is avail
nickel matte which melts at about l450° F., the furnace
able, proper rate and degree of heating can be achieved
blow may be started at a temperature of as low as 1550°
by control of oxygen addition. The temperature is raised
F. However, in most circumstances it is preferred to
as desulfurization proceeds until, at a sulfur content of 35 initiate the blow with commercial oxygen at much higher
»the bath of less than 4%, advantageously between about
temperatures than 1550" F., e.g., 2500° F., in order to
1% and about 3%, a temperature between about 3000°
avoid formation of nickel oxide slag and accretions. For
F., and 3200o F., is attained and maintained until final
sullides containing substantial amounts of iron as well as
sulphur elimination is achieved. It will be understood
nickel, such as pentlandite concentrate, and which re
that if the nickel contains a substantial proportion of cop 40 quire considerable slagging off of iron, the temperature
per, final ytemperatures will be significantly lower.
must be high enough to keep the slag in a fluid state.
In carrying one embodiment of the invention into prac
It is important that substantially all iron is eliminated
tice, nickel matte, which may contain less than about 1%
and any slag is removed from the furnace before blowing
iron, the amount of copper remaining after conventional
for sulfur removal to form metallic nickel is commenced.
separation of copper by ore dressing means, e.g., one part
It has been found that any formation of slag during re
of copper to ten parts of nickel, and some cobalt and
duction of the nickel matte to metallic nickel results in
precious metals, e.g., one part of cobalt to 25 parts of
serious decrease in gas-liquid contact and lowers oxygen
nickel and 2 ounces of precious metals per ton of nickel,
efficiency. Thus, only by keeping the surface of the
is treated, if desired, for the removal of the copper, co
molten bath reasonably clear of slag is economic desulfur
balt and precious metals as hereinafter described. The
ization in the autogenous reduction furnace possible.
matte is then transferred to the autogenous reduction fur 50
As sulfur elimination of the bath by the top blowing
nace wherein it is top blown with oxygen to nickel metal.
with oxygen or oxygen-enriched air proceeds, the tem
The autogenous reduction operation may be carried
perature of the bath is rapidly raised until the sulfur
out in the furnace depicted in FIG. l and FIG. 2 of the
content of the bath has been lowered to preferably be
accompanying drawing which show a longitudinel section
tween about 1% and about 3% and a bath temperature
of the furnace and a cross-section of the furnace through
of more than about 2800“ F. has been attained. It has
line 2-2 of FIG. 1, respectively. Referring to FIGS. 1
been found that the temperature of the reduction opera
and 2, the molten, nickel sulfide- containing material 10
tion and, in fact, the operation in general is controlled
by varying the oxygen supply, by observing exhaust gas
with high-grade refractory brick 12. The furnace may be
analysis and temperature and by varying turbulence.
tilted as desired for tapping by using tilting mechanism 60 During this first stage of sulfur elimination down to
20. The furnace has tires or drive rims 13 añixed cir
between about 1% and about 3% sulfur, it is preferable
is treated in a rotary kiln-type furnace 11 which is lined
cumferentíally around it and these tires rest on supporting
or drive wheels 14. Oxygen or oxygen-enriched air is
supplied by a water-cooled tube or pipe 15 which projects
to inject as much oxygen as is practicable without caus
ing undue nickel oxide slag formation or too much splash
formation at the mouth of the furnace. Use of
through seal 21 and opening 16 into the furnace. Ex 65 commercial oxygen allows more rapid nickel reduction
haust gases pass out of opening 17 at the other end of the
and production of gas rich in sulfur dioxide, e.g., 75%
furnace into the flue 18 which may be water-cooled and
sulfur dioxide, but excess heat is also thereby generated.
which may be swung away from the kiln opening to allow
Part of this heat is utilized for heating the charge to the
charging of fresh sulfide, flux or other materials through 70 temperature desired for final sulfur elimination, i.e., be
opening 17. Solids may be alternatively charged through
tween about 3000° F. and 3200° F. It may be desirable
opening 16 upon removal of pipe 15 and seal 21. Seal
to cool by injecting air into the furnace. The addition of
22 provides a gas-tight contact between the kiln and ñue
air may be, of course, undesirable in lowering the sulfur
18. Slag may be withdrawn by tilting the furnace and
dioxide content in the exhaust gas and increasing the gas
tapping from the top of the molten bath. At the com 75 quantity required per unit volume of injected oxygen.,
Cooling may be otherwise accomplished or may be sup
plemented by adding water to the gas stream rather than
air or by adding solid charge to 4the furnace or by a
combination of these techniques.
When desulfurization has proceeded to preferably -be
tween about 1% and about 3% sulfur, eg., 2% sulfur,
the. oxidizing. gases. should be. replaced, as. aforestated, by
substantially sulfur-free oxygen-impoverished gases, e.g.,
of' nickel -sulñde to metallic nickel by" our novel techñ
niques the final desulfur'izationvr from below 4% sulfur
is` carried out in a separate furnace inï the same manner'
as described hereinbefore.y This modified procedure may
be advantageous over doing` the complete operation in
one furnace. Thus, lfinal refining' may' be carried out in
a furnace the walls of which are'> not impregnated with
sulfide which has the: effect of> delaying the lowering of
neutral or somewhat reducing gases while heating or
maintaining the molten. bath to a temperature of‘ between
, re-absorption, ifi deoxidation is carried» out inside the
`about 3000° F. andV about 3,200o F. To maintain this
temperature in the bath, the neutral or reducing gases
furnace before tapping.V There is a further advantage
in using a second- furnace. iÍn that brick’ which ‘is not
must be at; a high temperature and this is best accom
impregnated with sulfide' will ‘allow increased refrac
tory strengthl `at the; high temperature necessary during
plished by adding aV highly combustible.` fuel such as
natural gas on propane together with the oxygen. The
fuel consumes any excess oxygen- and generates a high
temperature flame so that undue formation of nickel oxide
isthereby` prevented.. Theimpinging gases may thus ad
-sulîfur content in the bath and also presents a risk= of
final desulfurization. Furthermore, the two furnaceI tech
nique will allow steady' operation in one? furnace which
is utilizing oxygen only and so ‘attain an even. produc'
tion of gas with a. high sulfur dioxide content produced
vantageouslyI and. gradually be decreased> in. oxygen con
while usingf the second' furnace which isi utilizing oxygen
tent from that of comercial. oxygen,> to: oxygen-enriched 201 impoverished gases with. generally’ more rapid furnace
f air., to air; to oxygen-impoverishment, to non-oxidizing or
rotation. Also;-` any oxide formedr in theV first furnace
inert. and finally: to somewhat reducing. It will be under
could be- easily retained- therein' for subsequent reaction
stood that, once. adequate oxygen> supply is present in the
with green charge, with the` final blow in’ the second
bath,_ the functionof the impinging gases. is> heat supply
furnace. being carried out withoutÀ risk of slag. formation,`
and; insurance` of a low sulfur dioxide partial pressure
atmosphere. The. exact oxygenI content of> the. gas is` á;
It is to be noted that the herein described novel
reduction of. nickelY -sulñde to metallic nickel can be
attained with very smalll nickel- losses due either to
slagging as oxide; or. to'dustin‘g- in exhaust gases, i.e.,»` `a
nickely yield' in excess of 99%. We have produced
30 nickel by our process on‘» a tonnage basis containingv
variable determined. by and` within the. control: of the
furnace operator.; It has been: found that during this
final desulfurization period- best resultsV are obtained by.
increasingbathturbulence; especially if for any reason the
bath: hasV become over-oxidized:
By the above: novel- technique', desulfurization of the
lmolten' nickel' proceeds. to` less than 0:05.%Á sulfur, eigz,
0.01%y sulfur. Blowing'of molten nickeli sullidefmaterial
0.009%» sulfur, 0.02%- silicon, 0.00~l7%Í lead, 0.000l‘%
zinc„ 0\.0`004%l bismuth andl 0.00‘14.% antimony.
The extremeimportance
induced turbulence> and:
of.r the
bath„ as de
down to these. lowgsulfur contents on at tonnage basis has> 35 scribed hereinbefore, is demonstrated. by’ the failure to
been'foundíto'be` attainable in less than 81hours.
‘FinaL desulfùrization, which` isv carried. outî. under al
neutral'` or.V somewhat reducing atmosphere, is essentially
achieved; by“ reaction. between residual> sulfur.` and oxygen
in the molten metal. Asurprisingly high. absorption'off
oxygen takes placei in our-metal bath before any'visibl‘eA
obtain the desired results by blowing in `a stationary'
furnace as shown in Example VII described hereinafter
in which the nickel reduction reaction ceased" at a sulfur
content of 2% in the bath due Ito excessive locali oxida
tionand resultant formation of' a floating impenetrable,
hard, nickel. oxide blanket. A similar resultis obtained
oxide ñlm on its. Vsurface appears. Thus, inione case, arr
apparent dissolved oxygen content of 9.5% was obtained
while the metal was at a temperature of 3100o F., which
if attempts are made to. reduce the sulfur content of
tremely ñnely-divided', uniformlyY dispersed, solid’ nickeli
oxygen content insufficient to>cause` visibleà fò’rmation‘o‘f
interfering amountsí of nickel» oxide' dross on» the l surface
50' ofV the f agitated bath“, e'.g=, with» ai free oxygen= content' of’
the bath to below about 1% sulfur before replacing
is a much higher content-than-expected from study of the 45 the oxygen with high temperature,~weakly oxidizing, non
oxidizing, neutral and7or reducing gases which we have
nickel-oxygen equilibrium diagram. We believe a sub
termed oxygenLii-npover-ished' gases and which“ have an
stantial ' proportion of f this i oxygen wasy present‘ as anA ex
oxide. phase. Highoxygen. content in the sulfur-bearing
bathy is aikeyt featurelof’our turbulent metal desulfurizing
process in4 that. itâ permits' elimination. of the: oxidizing:
furnace.- atmosphere at amuclr` higher sulfur; contentiof'
themetalbath than in'the prior art.. Theo_xygenlcontentî
of the bath required for effective final desulfurization, of>
course, neednot` be as~high asthe above. Sulfur isyprefl
less» than about 3%». In ca‘se‘s whereA iron-containingv
nickel n‘latte»i-s~ii1'st'v blown in tliev autogenous reduction‘
furnace'for‘ironremoval, the‘slag formedV is treatedfon
on the surface, `i.e.,_ temperature and oxygen additionzis'
is low in
its nickel
so controlled as to maintain a shiny surface on the metal
erably, eliminatedlwithout formingwisible oxide floating;
of" its nickelE content. Ádvantageously, slagj
during the first stage of iron elimination‘wliicli
nickel i-s removed and treated for recovery of
content, if desired)A and the slag produced dur~
bath. Speed of reñning increases the higher the oxygen
for. recovery of itsinicke'l content upon further addition
content of the bath without surface oxide formation, e.g., 60 of'l concentrate-»tori matte.M AfterÍ af complete charge of
without substantial clouding of the bath surface.
molten matte rhas-'been built up in the autogenous furnace,
A‘sastatedhereinbefore, the surface `of the molten bath
slag produced from final iron elimination is removed
shouldâbekept free of slag or scum. For this purpose the
and> Imay be. treatedV in parallel' autogenous reduction>
oxidizing gases~ in~ the furnaceA preferably~ should' be» re-~
furnac'effor treatment with;v fresh sulfide.
placed î by, nonfoxidi'zing- gases before ß sulfur.. elimination;
In the `instances where nickel sulfide-materials’to b'eAL
has proceeded tofbelòw»about-l%~sulfur; e‘.g.^, 2% sulfur:
Deoxidation- ofsthe’- molten“ bath- after‘sulfur" removal ‘may’
be readily carried out .by carbon addition to the furnace.
Graphite has been found‘to be an excellent deoxidizing
agentcalthoughother: deoxidantsf such'asisilicon‘ or'alumi
num .mayl be utilized. A high residualIoxygen‘contentfin-
theibathl should; of course, be `avoided since'large quanti*
ties oficostly deoxidizing` agents ,are requiredand` possiblyy
violent; reactions may foccur; .
In a modiiìed procedure for carrying out the reduction'
treated lby, this process contain `amounts offcopp’er or
cobalt which may not be acceptable in the nickel metal,
eag.,.. more than. a'boutî.0."10!%iîA copper fand/.or more’A than
aboutl0.75§%Á cobalt in thezimetal, the -sulf‘rdetmaterial
must ¿be .processed for"y their îremoval.
The copper advantageously should:;be removed before`
desulfurizing. treatmentv in the top> blowna: reduction
furnace.l` Coppersremoval..byfmeans ofs‘a novelsolvent
extraction process, ie., high temperature liquid-:liquid
extraction, has been found particularly advantageous.
Table II
By this technique we have found that nickel sulfide with
a substantial copper content, e.g., a ratio of nickel:copper
of, for instance, 10:1 can be treated for copper .re
moval to produce a nickel sulûde having a residual cop~
As a general
rule nickel sulfide ores containing copper can be con
Sodium-Rich Frac
centrated by flotation so that the bulk of the nickel is
46. 4
in a concentrate containing nickel and copper in a ratio
of at least about 10:1 which can be readily decopperized
by our novel procedure. Much higher copper contents
can be extracted by this method if simpler prior sepa
ration, eg., of the natural minerals by flotation, is im
Ni: Cu
Percent Percent
per content of less than 0.10%, e.g., with a ratio of
nickelzcopper of at least about l000:1.
53. 6
4. 9
6. 2
64. 4
93. 8
In this novel liquid-liquid solvent extraction technique
about one-half to double by weight of a mixture of
15 sodium chloride and sodium sulfide may be melted with
This novel molten salt solvent extraction technique is
the copper-containing nickel sulfide material. The sodium
based on the use of sodium sulfide as the selective agent,
chloride-sodium sulfide mixture advantageously may con
probably a complexing agent, for copper sulfide. This
tain between about 25% and about 75% sodium chloride.
agent is dissolved in molten sodium chloride in which
It will be understood that although we prefer sodium
solution nickel has only a slight solubility and copper 20 chloride, other chloride modifiers such as the chlorides
a high solubility. An essential feature of this salt corn
of potassium, calcium and aluminum may be employed.
bination is its relatively low melting point of below
The nickel sulfide material and sodium salts are ad
vantageously melted at not below about 1350° F. and not
about 1300“ F. This permits the solvent extraction to
above about 1550° F., carefully mixed to insure ex
proceed at a temperature as low as about 1350° F. Thus,
the extraction is carried out close to the melting point 25 cellent countercurrent liquid-liquid contact and then
separated by gravity into copper-rich and nickel-rich
of the metal sulfides which is the optimum temperature
fractions. A preferred apparatus for this purpose is a
for liquid copper-nickel separation. This low operating
liquid-liquid extraction column as shown in FIGURE
temperature and the high water solubility of the ex
3. The substantially copper-free nickel sulfide product
tractant have the additional important advantages of
economy in reagent, fuel and refractories consumption. 30 may be air blown for slagging of residual sodium salts
and then transferred directly to the autogenous reduction
This novel separation technique is outstanding in that
furnace to be blown to metallic nickel as described here
sequestration of copper by the solvent and isolation of
inbefore. The copper-sodium rich product may be
nickel are both highly effective while the cost of labor,
treated by water leaching to recover copper and the
supplies and equipment is relatively low. Our procedure
sodium salts and residual nickel. Alternatively, the ex
permits economical removal of co-pper sulfide, entirely
traction may be carried out in other apparatus, e.g., in
beyond the capability of the existing art, from sulfides
an appropriately designed, countercurrently operated ro~
having a broad range of nickel to copper ratios to yield
tating kiln or by simple ladle mixing, settling and bottom
nickel sulfide having a nickel to copper ratio of greater
pouring in a countercurrent multi-stage operation. The
than l000:1.
40 advantageous results obtained by our novel solvent ex
The highly beneficial effect of using a solvent, such
traction technique rfor extracting copper from nickel
as sodium chloride for sodium sulfide is clearly demon
sulñde are shown in Examples II and III.
strated by the following example:
150 grams of matte, containing 68.2% nickel and 3.25%
. A nickel matte containing 3.25% copper with the bal
copper, was mixed with 150 grams of sodium sulñde
and the mixture was melted at 1550“ F. The upper
sodi-um-rich and the lower nickel-rich fractions were
tapped from the bottom of the crucible into separate
containers although there was found to be no sharp
physical definition between them. Analyses of these
upper and lower layers gave the results as shown in
Table I.
ance mainly nickel and sulfur, was treated for copper
extraction by a multi-stage countercurrent liquid-liquid
extraction at 1550° F. The solvent, 50% by weight of
sodium sulfide and 50% by weight of sodium chloride,
was added to an equal weight of nickel matte in a cruci
ble, mixed thoroughly and the nickel sulfide was tapped
from the bottom at each of four extraction stages. Salt
55 fraction was mixed with the appropriate nickel sulfide
bottoms in each of these stages. The final products from
the four-stage treatment analyzed as follows:
Table I
Ni: Qu
Ratio Total
Percent Percent
Upper Sodium-Rich Frac
tion ................... _-
49. 4
1. 7
30. 0
43. 5
50. 6
1. 4
56. 5
Lower Nickel-Rich Frac
tion ................... _-
65 Final Copper-Rich Solvent--..
4. 2U
1. 2
Final Nickel Sulfìde _________ _-
63. 3
The test was then repeated except that 75 grams of
sodium chloride and 75 grams of sodium sulfide were
A nickel matte containing 4.8% copper with the bal
used instead of 150 grams of sodium sulfide. Two dis
ance mainly nickel and sulfur was treated for copper ex
tinct liquid fractions were obtained by this test which
traction in the same way as in Example II except that
were cleanly separated by bottom tapping. The two
the countercurrent extraction was conducted at 1400° F.
fractions were then analyzed to give the results as shown
The final products from the four-stage treatment analyzed
in Table II.
75 as follows:
sodium salts, have been removed by ra brief, relatively low
Final Copper-Rich Solvent_l____,_~- _________ -_
Final Nickel sulfide .....................
temperature, air- blow in> a separate vessel and decantedr for
reuse. However, in cases where there. are precious` metal
valuesv associated with the. nickel suliide material the
precious metals may be removed by known meansA such
0.06 i
63,3 l 105ml
as by b‘lowingpto create a sulfur deficiency, cooling, solidi
fying, grinding and removing the, precious»` metals, con
centratedÍ in the metallics. The.` nickel sulfide, may then
It has been found highly advantageous to use a con
tinuous countercurrent solvent extraction technique to
attain copper removal down to- less than about 0.1%
copper in the nickel sulñde material. The countercur
rent liquid-liquid extraction may take- place in a standardç
type of apparatus such as that> shown in FIGURE 3
which depicts. the diagrammatic cross-section of‘ a baille
plate» column in which theV copper-containing nickel sul
be, water leached- to. remove sodium salts, dried land then
fed directly- tov the autogenousl reduction kiln.
In speciall circumstances, cobalt elimination may be
accomplished during 4conversion of the; sulfide, material
to metal by blowing the molten material with an oxygen
rich gas at a sulfur content off; more than about 3% to
selectively oxidize- the cobalt in the presence of a ilux
such as silica. The cobaltr is then skimmed' off.' as slag’.
The sulfur content of‘ the molten charge is maintained
tide is treated with the~ molten salt mixture for elimina
at above about 3% sulfur by continuously »ad‘ding fresh
tion of copper. Referring` to FIGURE 3, solid baffle
sulfide material' to the autogenous reduction furnace while
plates. 30, which extend- partially across the colunm- cross
top-blowing at between about 2300~o F; and about2800“
section, are placed at suitable intervals in the column.
F24 for sulfur :and cobalt removal'. When the furnace
Molten copper-containing nickel sulfide from storage tank
has receivedV ia full charge and' adequate cobalt removal
31~` is introduced through line 32' and variable orifice 33
has been achieved, the top-blowing of" the molten charge
into the top of~ the column at 3‘4‘. Molten sodium salt
is ‘then completed as described hereinbefore to form
solvent from storage tank 35 is introduced through line
metallic nickel; The cobalt-rich slag can be conveniently
36 and: variable oriñce 3l'7` into` the bottom ofthe column
treated for cobalt recovery by known means. It will3 be
at 3S. Nickelï sulfide from whichl copper has been elimi
understood', however,vthat formation ofthisslag can inter
nated. is drawn olf the. bottom of the `column throughv
fere with our process, as hereinbefore described, so that
line 39s and. variable oriû’ce 40. Copper-rich solvent- is
cobalt removalY in this manner is notv always practicable.
drawn» off-` the top ofthe column-through line 41. HeatY
The following example illustrates the, satisfactory re;
is. supplied tothe column and` to the tanks-31 and» 35' tov 3.0
sults that may be obtained by our technique for eliminat
maintain> the sulñde and sodium salts in a molten condi
ing> cobalty from nickel’ sulfide:
tion and at the» separation temperature desired such as by
way of electric immersion heaters 42 and external electric
heaters 43;
217% cobalt and the
The heavier nickel sulfide flows along each- baille,
balance substantially nickel and1 sulfur-was partially re
which is. supplied with` a short lip 44 so that each is sub
duced to 10% sulfur at 2500"" F. byA top blowing with
stantially a tray, overiiows» over the lip and then flows
Siliceous ilux` was then, added and the- oxygen
downward tothe next tray; The lighter sodium-> salt
blow was continued for-15’ minutes» to selectivelyfoxidize
solvent flows upwardV around» each baille and through- the
cobalt and remove it-îas slag.r The final low-sulfurA matte
free area between the tray and the inside wallsV of the
contained* 0.6%' cobalt, 90.3% nickel and the balance
»column Thus, as» the sodium salt- solvent rises through
mainly sulfur: The ratio- of nickel to cobalt was in
the-_ falling nickel sulñ’de and- removes copper sulfide it
creasedby this treatment; from` 25: 1- to- 150: 1l.
becomes progressivelyl richer in copper-sullide, while the
For the purpose of- giving those skilledl in the ar-t
nì'ckelî sulfide has more and more copper- sulfide extractedvv
a better- understanding; of ‘the` invention, the following
as it flows- downward.
‘ illustrative examples-are given:`
A; mini-plant multi-tray column of the above gen
eralv design, 3 inchesLD. by 4S` inches- high was operated
at’y a feed rat-e of up to. one-half' ton per> day- of copper
nickel; copper, cobalt; iron
bearing‘nickel4 suliideemploying as a- solvent a salt4 mix
and-gangueminerals was treatedï by conventional methods
ture consisting. of sodiuml sulfide» and sodium chloride ~ to produce a concentrate containing-12.0% nickel, 1.6%
and containing between 25%A and 75 %- sodium chloride.
copper,4 0.4% cobalt, 40.0% iron, 311.0% sulfur and 7%
ln. this-_ simple device we were able to continuously-lower
silica. This- concentrate was autogenously smeltedï with
the copper content of the nickel matte in a ratio of about
oxygen to a matte containing 48.2%' nickel, 8.6% copper,
110:1, producing: a> nickel‘l sulñ‘de- with a Ni:CuA ratio ex
1.6% cobalt, 28% sulfur- and’ the balance mainly iron.
ceedingV 1000:»1Íwhen treating'mattes in the 0.75% Cu l rFheslag from this operation-containing 115% nickel' was.
to. 3.5% copper range. The test results-vindicatedv that
removedlfor separate treatment“ to recover its-metallvalues.
nickel' sulñde- having a` substantially-higher copper con
rlibe-marte was then` blown with oxygen to produce a sub-V
tent, e.g., 10% copper, could also be successfully treated.
stantially` iron-free» matte which was tapped: to leave» a
Basedr on»` equilibrium data- established -for our novel,`
high nickel slag» in--the-` furnace-for subsequent reduction
liquidi-liquid- extractionA system in the laboratory and fur,
with- fresh- charge. This- matte was treated for copper
therv substantiated by the above mini-plant experiments,
removal 'at-> 1400“- F. by our `solvent extraction technique
copper reductions by weighty of 100:1 or more` can be
as `describedlhereinbefore» in Example III. The- resulting
realized from cupriferous nickel' sulfide when using our .
substantially iron- andcopper-free matte» was- treated toy
process` in commercial extraction equipment such» as tray4
remove cobalt by the- process described in Example IV;
6.5" The thus-treatedf matte wasV top blown- with oxygen atI
I-t- is to b_e observed that our- novel: technique for» re
a temperature--rising-to 2850°` F. 'to> a sulfur content of
moving copper- from nickel »rn-attesi before blowing to
32%'. The¿ thus blown matte can then b_e treated, as hasà
metalliçâ- nickel permits»> a> much higher degree of“ copper.`
been described above, for- final sulfur elimination.
columns,- Packed` columns-.or mixer-settlers.
elimination therefrom than can; be obtained; by controlled
coolingt andullotation, of -the- matte, ire., less- than 0.05%Cu- as comparedïto morethan:y 0.50%
As. stated. hereinbefore` the. molten- nickel matteY from.i
which thecopper has advantageously-been ext-racteddown-_t
to below about 0.310% coppermay-betransferredto theV
autogenpus reduction; furnace, preferably after residuale
4:4` tons- of ` a` molten nickel matte containing. 70.9%v
nickel, 4.8% copper, 1.0% iron and 23.3% sulfur were
topblown with-,oxygen in a furnace, similar to that-shown
in FIGURE l2,’ rotating at 20'r.p.m. at a temperature
rising to 3000° F.
Cooling was accomplished4 by iti-_
jecting air with the oxygen. The molten material was
blown down to 1.4% sulfur at which point propane gas
was injected with the oxygen and rotation of the furnace
Furthermore, it is to be observed that our novel copper
removal technique, by high temperature liquid-liquid
separation is a major advance over the now long obsolete
was increased to 30 r.p.m. Enough propane was injected
Orford process which was abandoned because of its high
to produce a somewhat reducing atmosphere in the
cost and the low separation efficiency of its batch-type
furnace. The temperature of the bath rose to and was
held at about 3l00° F. and the molten bath was blown
to a sulfur content of 0.02%. The bath at the end of
the blow had an oxygen content of 1.9% which was re
moved by adding graphite to the bath in the furnace.
Total blowing time to ñnal desulfurization was seven
hours and fifty minutes.
To illustrate the extreme importance of strong mechani
cally induced agitation of the molten bath during blow
ing, 4.3 tons of the same nickel matte as treated in Ex
ample VI were blown with oxygen in a manner similar to
t-hat used in these examples except that the furnace re
mained stationary. After eight hours and forty minutes
of blowing the sulfur content of the metal had been de
creased to only 2%, further reaction ceased and blow
ing had to be discontinued because of nickel oxide ac
cumulation with formation of a heavy impenetrable layer
of slag floating on the metal.
,_ It -is to be observed that by the above described in
vention, metallic nickel can be produced directly from
nickel concentrates obtained by flotation of nickel sulfide
This application is a continuation-in-part of our co
pending U.S. application Serial No. 839,431, filed Sep
tember l1, 1959, now abandoned.
Although the »present invention has been described in
conjunction with preferred embodiments, it is to be un
derstood that modifications and variations may be re
sorted to without departing from the spirit and scope
of the invention, as those skilled in the art will readily
understand. Thus, our process may be employed for
the treatment of copper-rich materials, eg., copper flota
tion concentrates and mattes to yield directly fire-refined
or anode copper.
Such modifications and variations are
considered to be within the purview and scope of «the
invention and appended clams.
We claim:
1. An improved process for autogenously converting
a nickel sulfide material to produce nickel of low sulfur
content which comprises directing oxidizing gases from
the group consisting of commercial oxygen and oxygen
-enriched air into the exposed surface of a molten bath
of said sulfide material, while avoiding sidewall and bot
tom blowing of said gases through the bath, and main
taining the bath during the converting in a state of
ores after copper removal by our novel techniques as
described hereinbefore. It is known that pentlandite con 30 turbulence with non-pneumatic, mechanically induced
agitation, said agitation being maintained during the di
centrate may be oxygen-flash smelted to a nickel matte,
recting of said oxidizing gases, to promote intimate and
as disclosed by one of the present inventors in U.S. Patent
efficient gas-liquid-solid contact and uniform distribution
No. 2,668,107. Our new process is an improvement over
of oxygen throughout the bath and its rapid reaction with
that described in this patent in that our product is metallic
sulfur therein; raising the bath temperature as desul
nickel instead of nickel matte with a high impurities con
furization proceeds to more than about 2800° F.; chang
tent. Summarizing our technique for treating nickel con
ing said gases being introduced into the bath surface
centrates by our novel process to obtain metallic nickel
to hot, substantially sulfur-free gases from the group
directly, we charge dry nickel concentrate, eg., pentlandite
consisting of neutral and reducing gases having an Oxy
concentrate, into molten material in an autogenous re
duction furnace, such as described hereinbefore, and 40 gen content insufficient to cause visible formation of
interfering amounts of nickel oxide dross on the surface
blow for removal of iron which may be slagged off by
of the bath when the sulfur content of the bath is still
addition of siliceous flux. The slag produced during
substantial but is less than about 4% and the oxygen
the first stage of iron elimination, low in nickel, is re
content of ‘the bath is at least sufiicient to oxidize the
moved from the furnace and the slag produced during
sulfur content, the bath being at a temperature of at
the final stage of iron elimination is left in the furnace for
least about 3000o F. and maintained in a turbulent state
extraction of its nickel content upon further addition
by non-pneumatic, induced agitation upon changing
of concentrate. After iron removal is completed, the
from oxygen-rich gases; and maintaining a bath tem
molten material may be treated for copper removal and
perature of at least about 3000° F. in the presence of
Iit is then blown directly to metallic nickel both of which
50 said hot gases to continue the reaction between sulfur
operations are above described in detail.
and oxygen in -the turbulent bath and to produce nickel
It is further to be observed that the hereindescribed
with a sulfur content low enough below 0.5% for re
process is highly suitable for lthe treatment of crude
moval by desulfurization.
mattes obtained from lateritic nickel-containing ores as
2. A process as described in claim 1 in which me
for instance, by the process described by one of the
present inventors in the copending U.S. patent applica 55 chanically induced agitation of the molten Ibath is at
tained by rotation of the furnace and the metallic nickel
tion Serial No. 51,418, filed August 23, 1960, now U.S.
obtained contains not more than about 0.02% sulfur.
Patent 3,004,846. These mattes which contain substan
3. An improved process for autogenously converting
tial amounts of iron and some cobalt can be blown in
a nickel sulfide material to produce refined nickel. of
the autogenous reduction furnace for iron, sulfur and
cobalt removal and direct production of metallic nickel. 60 low sulfur content which comprises blowing commer
cial oxygen onto the exposed surface of a molten bath
Since these lateritic ores normally contain substantially
of said sulfide material While avoiding sidewall and bot
no copper Or precious metals, the molten material need
tom blowing of said oxygen through the bath, and main
not be treated for their removal but in the case of ores
taining the bath substantially slag free during the blow
with a substantial cobalt content, the matte may be
treated for cobalt removal as described herein.
65 ing with oxygen and in »a state of turbulence with me
It is to be observed also that prior art techniques for
directly reducing nickel-rich matte to commercial metal
lic nickel or nickel-copper alloys failed utterly because
chanically induced agitation, said agitation being main
tained during the blowing, to promote intimate and effi
cient gas-liquid-solid contact and uniform distribution
of oxygen throughout the bath and its rapid reaction
of formation of metal oxides rather than metal with re
sultant massive accumulations of accretions and of float 70 with sulfur therein and to produce off-gas rich in sulfur
dioxide; raising the bath temperature as desulfurization
ing dross which smothered the reaction long before it
was complete and also because of destruction of refrac
proceeds to more than about 2800“ F. whileV continuing
tories due to subsurface blowing of the bath and/or
said blowing with oxygen; transferring the bath to a
substantially sulfide-free furnace environment when the
lack of proper bath turbulence with consequent exces
sive local temperature rise.
75 sulfur content of said bath is still substantial but is less
thanl .about 4% and its oxygen content isr at least, suvfli‘-,A
amounts et nickel. @aide dross on the. surface.. of the bath,
cient to oxidize. theY sulfur content; blowing onto said
transferred bath, maintained` in e, state 0f turbulence by
when itsY sulfur content is. between about, 1% and. ebent
3% and` its oxygen. cententiset least snñicient te QXidize
tbe snlfnr centent, the bathr beingÍ at temperature. of;
et` leest nbent 300.0” 1?- a_nd maintained in e, turbulent
mechanically induced agitation, het gases- fiern. the grens
consisting ef neutral and reducing gases substantially
free 0f sulfur dicnide and having en Oxygen content in-V
sntiicient tc. canse visible iennationA of. interfering
einennts ci nickel Oxide dress en the surface 0f tbe betln
tbe transferred. beth beine at n temneretnre. cf, at leest
ebbnt 3Q0O° lî-s, maintaining a batn temperature ef at
least about 3000° F; in the presence of said hot gases to
state by yrnecli.en_icnlr induced aaitatien nnen changing
frein Oxygen; and, maintaining, n bntb temperaturev 0f at.
least> about'` 3000° E. in the presence of said hot gases to
cçmtinue- the reaction between sulfur- and oxygen in the
turbulent bath and to produce refined, pig nickel with a
low sulfur con-tent of- not more than of the order o_f‘
continue the reaction between sulfur and oxygen in the
turbulent beth end te Obtain rnetnllic. nickel; and, dc
about 0.05%.
6`~ A process as `described in claim 5A in which the
oxidizing the molten bath to produce refined, nickel' with
nickel-rich sulfide material contains cobaltl and wherein,
after iron is_ oxidized, slagged and drawn off, the sulfur
content ofthe metal bat-h >is maintained at greater than
a low sulfur content of not more than of; the order of
about 0.05%.l
about 3% by adding fresh sulfide material while blow
4. In a process for producing refined, metallic nickel
fromv nickel-richÑ sulfide materials containing iron in’
ing with oxygen at between about- 2_300-°- F. andl about
2800" F.` «to oxidize the cobalt and remove it» as_ slag.
which the sulfide materialV is smelted, to produce a nickel
iron matte andthe nickel-iron matte is` blown to remove 2.0, 7i. An improved process for- -au-togenously converting a
nickel-copper sulfide material to produce nickelecopper
iron therefrom and form a nickel matte, the improve
mentW which> comprises autogenously smelting the nickel
alloy of "low sulfur content which comprises directing
matte by blowing commercial oxygen onto the exposed
oxygen-rich gases from the group consisting of com
mercial` oxygen and oxygen-enriched- air into the. ex
surface of» a molten ba-th4 of said nickel matte at a‘tem
perature ofV at lea’st‘- about 2400“ F., while avoiding~ side 2,51 posed sur-face tof-V a moltenf bath of said sulfide material,
while avoiding sidewall and` bottom blowing of‘said gasesA
wall and bottom blowing of said oxygen through the
through the bath, and maintaining the. bath during the
bath, and maintaining- the'bathv 4substantially free of slag
converting. in a state of turbulence. with> non-pneumatic,
during the blowing with oxygen and in a state of turbu
mechanically induced4 agitation, said agitation being main
lence with mechanically induced agitation, said agitationJ
being maintained during the blowing, to promote inti 30. tained during the, directing of said oxygen-.nich gases, to,
mate and efficientl gas-liquid-solid> contact and uniform
promote intimate and efficient gas-.liquid-sc_>lidl contact
distribution of- oxygen throughout the bath and its rapid‘and> uniform distribution of'A oxygen throughout therba‘th,
reaction with sulfur therein; raising. the bath- temperaturel
4and its rapid reactions with sulfur therein; raising the,
as desulfurization proceeds» tomorethan about 2800“ F;
bath temperature as desulfurization proceeds while` main-V.
while continuing. said blowing with oxygen; changing
taining its surface substantially> -free of- oxide dross;
said oxygen being directed onto the molten bath to hot ' changing. said; gases. berng mtroduced; into the. bath, sur
face to4 hot, substantially gases` from the».
gases from the group consisting of neutral and reducing
group consisting off neutral and. reducing gases having
gases substantially free of sulfur dioxiden and having. an>
oxygen content insufficient to cause visible formation of
an- oxygen content-insuliicientf to cause visible formation,
interfering amounts of nickel-z oxideA dross on the surfaceof; interfering amounts1 of nickel; oxide dross> on the` sur-_.
of the bath when its sulfur content` is between about
faceA of the bath> whenl its, sulfur; content ist still ‘sub-_
1% and -about 3%. `and its oxygen contentr is at least`
stantial but is less; than` about,V 4%> andI itsf oxygen con-l
sufficient to oxidize the sulfur content, the bath. being at.
tent is. at.- least sufficient. to oxidize the, sulfur cen-tent,
a temperature of'between about 3.0009 F; and' 3200"v F.
the bath being.` maintained ina tnrbnlentzstate by nen-`
and> maintainedl in a turbulent- state by, mechanically ín 45 nnenrnatie. induced: asitatien'nndf at a bien temeer-attire
duced- agit-ation upon changing from oxygen; andi main-_
sntiicient, te; minimize. tbe- terrnatien et. oxide dress en
taining -a bath, temperature of» between about 3000? F`
tbe surface-,i nf: the; nieleelnepree alley. beth. nnen, c_bensfL
‘ and 3200?
in the presence of'said hot gasesA to con-_
ing frein Oxygen-cicli; gases; and; maintaining the bien
tinue the reaction between sulfur and oxygen in theÁ
temperature in tbe, beth. in tbe. presence. ciy saidÑ bet arises~
turbulent bathV and to, produce refined, pig nickel: with, a 5.o te. centinne tbe reaction between sulfur; and. Oxygen. in.
low sulfur content of; not more- than of»v the order of`
the- tnrbnlent; beth and te, Produce nickel-copper».- aller
about 0.05%.
with, al sulfur.. content loWl éuQllgh below 0».ì5,%_ for re-A
5. Ant autogenous process for producing refined metal
lic nickel directly from nickel-rich sulfide materials con
moval; b_y. desulfurizatiorn.
flux and drawing off the slag so formed; raising the tem
perature of the molten bath after slagging of said iron
pbase; serénratina seid liquid nbasesz. trentina said' Unger
8, An Aimproved process, for eliminating` copper. from`
taining iron which comprises directing commercial, oxy 55 andÍ autogenously, smelting, a n_iclçel> sulfide. material con
tainingcóbpertovnr-ednce refined, nignickel ci lewfsnlinr
genA onto the surface of'a molten bat-hof said nickel-rich
content which comprises` melting and mixing between
sulfide material while avoiding sidewall and bottom blow
ing of» said oxygen through the bath, said bath being
abcnt ene-half tedenble-by weishtei a; mixture ct sedinrn»
maintained in a state of~ turbulence by mechanically in_
chloride, and, sodiumv sulfide. salt-s with; said nickel sulfide
duced agitation, said- agitation being maintained during 60 materiel-in the ineltenI state;> allowing said melten innss`
seperate ntog en upper center-rich- and`- sodium salt-`
the directing of" said oxygen, to oxidize iron`> and. de
containing liquidî phase. and a lower nickel` sulfide liquidsulfurize the bath; slagging the `oxidized iron with silica
and as desulfurization proceeds to attain a bath tempera
liquid‘phase for‘recovery of the sodium salts contained
65 therein; oxidizing and removing sodium salts from the
lower, nickel sulfide liquid phase; directing 4oxygen onto
ture of at least about 2800° F., While continuing the
the exposed surface of la molten bath of said nickel sul
directing of oxygen onto the molten bath maintained in
fide phase, while avoiding sidewall and bottom blowing
a state of induced turbulence to promote intimate and
of said oxygen through the bath, and maintaining the
efficient gas-liquid-solid contact and uniform distribu
tion of oxygen throughout the bath and its rapid reac 70 bath `during the smelting in a state of turbulence with
mechanically induced agitation, said agitation being main
tion with sulfur therein; changing said oxygen being di
tained during the directing of 4said oxygen, to promote
rected onto the molten bath to hot gases from the group
consisting of neutral and reducing gases substantially
intimate and eiiicient gas-liquid-solid contact and uniform
free of sulfur dioxide and having an oxygen content in
distribution of oxygen throughout the bath and its rapid
sufficient to cause visible formation of interfering 75 reaction with sulfur therein; raising the bath temperature
as desulfurization proceeds to more than about 2800° F.
fide material with a copper content of at least about
0.50% for elimination of the copper and cobalt and re
while continuing the directing of oxygen onto the bath;
changing said oxygen being directed onto the molten bath
covery of the nickel contained therein as refined, pig
nickel of low sulfur content, the improvement which com
to hot gases from the group consisting of neutral and
reducing gases substantially free of sulfur dioxide and hav CW prises melting and mixing between about one-half to
double by weight of a salt mixture of sodium sulfide and
ing an oxygen content insufficient to cause visible forma
a metal chloride from the group consisting of the chlo
tion of interfering amounts of nickel oxide dross on the
rides of sodium, potassium, calcium and aluminum with
surface of the bath when its sulfur content is between
said nickel sulfide material in the molten state; allowing
about 1% and about 3% and its oxygen content is at
least sufiicient to oxidize the sulfur content, the bath being 10 said molten mass to separate into an upper copper sulfide
salt mixture liquid phase and a lower nickel sulfide liquid
at a temperature of at least about 3000u F. and main
phase; repeating the foregoing operations in a counter
tained in a turbulent state by mechanically induced agita
tion upon said changing from oxygen; and _maintaining
current manner; separating the final liquid phases; treat
ing the upper liquid phase for recovery of the copper and
a bath temperature of at least about 3000° F. in the
the salt mixture contained therein; oxidizing and removing
presence of said hot gases to continue the reaction between
salt mixture from the final, lower, nickel sulfide liquid
sulfur and oxygen in the turbulent bath and to produce
phase; directing commercial oxygen onto the exposed
refined, pig nickel with a low sulfur content of not more
surface of a molten bath of said nickel sulfide from which
than of the order of about 0.05%.
copper has been eliminated, While avoiding sidewall and
9. In the treatment of a nickel sulfide material with a
copper content of at least about 0.50% for elimination 20 bottom blowing of said oxygen through the bath, and
maintaining the bath in a state of turbulence by mechani
of the copper and recovery of the nickel contained therein,
the improvement which comprises melting and mixing
cally induced agitation, said agitation being maintained
during the directing of said oxygen, to promote intimate
and efficient gas-liquid-solid contact and uniform distribu
consisting of sodium chloride, potassium chloride, calcium 25 tion of oxygen throughout the bath and its rapid reaction
with sulfur therein; maintaining the _sulfur content of
chloride and aluminum chloride with said nickel sul
the molten bath at more than about 3% by adding sub
fide material inthe molten state; allowing said molten mass
stantially copper-free fresh nickel sulfide material, while
to separate into an upper copper sulfide-salt mixture liquid
blowing with oxygen at between about 2300° F. and
phase and a lower nickel sulfide liquid phase; separating
between about one-half to double by weight of a salt mix
ture of sodium sulfide and a metal chloride from the group
said liquid phases; treating said upper liquid phase for 30 about 2800° F. to oxidize the cobalt and remove it as slag;
raising the temperature of the molten bath when cobalt
has been eliminated and slagged off and as desulfurization
proceeds to more than about 2800° F. while continuing
liquid phase; and treating said nickel sulfide liquid phase
the directing of oxygen onto the bath; changing said
for recovery of the nickel contained therein.
10. A process as described in claim 9 in which the 35 oxygen being directed onto the molten bath to hot gases
from the group consisting of neutral and reducing gases
salt mixture is sodium chloride and sodium sulfide and
substantially free of sulphur dioxide and having an oxygen
contains between about 25% and about 75% sodium chlo
recovery of the salt mixture contained therein; oxidizing
and removing salt mixture from the lower, nickel sulfide
ride, the separation of the copper sulfide-salt mixture phase
content insufi’icient to cause visible formation of interfer
ing amounts of nickel oxide dross on the surface of the
bath when its sulfur content is still substantial but is less
liquid extraction column and the nickel sulfide phase sepa
than about 4% and its oxygen content is at least suffi
rated out contains less than 0.10% copper.
cient to oxidize the sulfur content, the bath being at a
ll. In the treatment of a nickel sulfide material with
temperature of between about 3000° F. and 3200° F. and
a copper content of at least about 0.50% for elimination
of the copper and recovery of the nickel contained therein, 45 maintained in a turbulent state by mechanically induced
agitation upon said changing from oxygen; and main
the improvement which comprises melting and mixing
taining a bath temperature of between about 3000" F. and
between about one-half to double by weight of a mixture
3200° F. in the presence of said hot gases to continue the
of sodium chloride and sodium sulfide salts containing
reaction between sulfur and oxygen in the turbulent bath
between about 25 % and about 75% sodium chloride with
and to produce refined, pig nickel with a low sulfur con
said nickel sulfide material in the molten state at a tem
tent of not more than of the order of about 0.05%.
perature of not below about 1350" F. and not above about
1550° F.; allowing said molten mass to separate into an
and the nickel sulfide phase is carried out in a liquid
upper copper sulfide and sodium salt-containing liquid
phase and a lower nickel sulfide liquid phase with a cop
References Cited in the file of this patent
per content of less than about 0.10%; separating said
upper and lower phases by pouring one from the other in
the liquid state; treating said upper liquid phase for re
covery of the sodium salts contained therein; reverting
said sodium salts for further copper elimination; oxidizing
and removing any sodium salts from the lower, nickel 60 2,396,792
sulfide liquid phase; and treating the nickel sulfide remain
ing for recovery of the nickel contained therein.
12. In the treatment of cobalt-containing nickel sul
Lellep _______________ __ Sept. 14, 1926
Lellep ________________ __ Apr. 5, 1927
Wilenchik ____________ __ Feb. 26, 1929
McGregor ____________ __ Sept. 20, 1932
Kroll ________________ __ Mar. 19, 1946
Kalling et al ___________ __ May 27, 1952
Lichty ...... __ _______ __ Sept. 29, 1953
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