Improvements in or relating to Obtaining and Separating Sulphide of Nickel for use in Metallurgical Operations in the Treatment of Mattes of Copper, Nickel, Iron, and other Metals.
Year: 1893

page_text: Date of Application, 10th Jan., 1893-Accepted, 25th Mar., 1893
COMPLETE SPECIFICATION.
Improvements in or relating to Obtaining and Separating Sulphide
of Nickel for use in Metallurgical Operations in the Treatment
of Mattes of Copper, Nickel, Iron, and other Metals.
A communication by ROBERT M. THOMPSON, of 45, West Forty-fifth Street,
New York, in the County and State of New York, United States of America,
Copper Manufacturer.
I, WILLIAM PHILLIPS THOMPSON F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 6 Lord Street, Liverpool and 6, Bank Street, Manchester, both
in the County of Lancaster and 323 High Holborn in the County of Middlesex
Civil Engineer do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:-
The invention relates to an improvement in method or process for obtaining and
separating commercially pure sulphide of nickel for use in metallurgical operations,
in the treatment of mattes of copper, nickel, iron and other metals, as the same
result from the various operations of ore smelting, and more particularly to a
method or process in which the separation is effected by the addition of certain
chemical reagents, which not alone change the chemical composition of the smelted
mass, but also tend to produce, after smelting, great fluidity in the mass, whereby
the various metals or salts of metal contained therein assume upon cooling, by
reason of their varying specific gravity, such relative positions with reference to
each other, that they may be readily separated by mechanical means, or by hand.
Now my correspondent has discovered that when nickel is combined with other
metals, as for instance, iron and copper, or either of them, in an ordinary matte,
produced from or by the primary treatment of the ores of these metals, in the ordinary
operation of smelting in any convenient form of furnace, they exist probably as a
combined molecule, and the affinity of the various metals for the sulphur is different,
and when the mattes or other substances containing nickel are treated with a certain
class of alkalies or salts of the alkaline bases, rich in oxygen, such as carbonates of
the various alkaline metals or ammonia or caustic alkalies, such as potash or soda
or either of them, or any of them mixed together, the combined molecule is split
up, and the nickel is desulphurized and changed either into a crude metallic form,
or into a sulphide differing in chemical composition from that in which it existed in
the matte or ore, and containing more or less sulphur, according to conditions, and
the product of the smelting operation, so far as it consists of this crude nickel or
nickel sulphide, will be of greater specific gravity than the other metals and may
be readily separated therefrom.
When any of the substances above mentioned are added to a charge of matte, in
a cupola, or blast furnace, in suitable quantities, the caustic alkali, or carbonate,
tends to absorb a portion of the sulphur from the matte, and to form a sulphide of
the particular alkaline base, which is employed. In so doing it breaks up the
combined molecule in which the metals exist, and takes from part of the metals
the greater part of the sulphur combined in them. As under these conditions
the sulphur has a less affinity for the nickel than for the other metals, a propor-
tionately larger amount of nickel than of the other metals is reduced to a metallic
state, and when the smelted mass is tapped after smelting from the furnace, and
allowed to cool in an ordinary cooling bed, or in any mould or slag pot, two distinct
compounds will be found to have been produced, which will assume with reference
to each other the relative position of layers or strata, and which are called "tops
and "bottoms" according to their position. The "tops" so-called consist of sulphide
"

page_text: .
of the alkaline base, sulphide of copper and some sulphide of iron and nickel, while the
"bottoms" consist of a small amount of alkali and copper, iron and nickel in crude
metallic state and perhaps a little sulphide of these metals, the proportion of the
nickel being largely in excess of the proportion of the iron and copper.
The separation of the "tops" from the " bottoms" may be effected if desired while
they are still liquid, by allowing the mass to settle, and then siphoning or pouring
off the former in any convenient manner, for the reason that in practice the
"bottoms" solidify rapidly while the "tops" remain liquid, or the mass may be
allowed to cool and harden, and the portions separated by mechanical means or by
hand.
If, now, the so-called "bottoms" resultant from this operation or step in the
separation, are subjected to further treatment by again smelting or melting in any
shaft or other suitable furnace, with a sulphide of any one of alkaline base such as
sulphide of soda, sulphide of potash, or sulphide of ammonia, containing preferably
an excess of free sulphuric acid, the metals by reabsorbing sulphur from the
sulphide of the alkaline base will be reconverted into sulphides and the alkali
converted into caustic alkali. The tendency of the sulphide thus formed is not to
form a compound molecule such as existed in the original ore or matte, but separate
molecules of sulphides of the various metals present.
The copper and iron associated with the metallic nickel in the "bottoms
resultant from the first treatment with caustic alkalies or carbonates of the alkaline
bases, exist either as a different sulphide from that in which it existed before or in
a lower sulphide, and when any sulphide of an alkaline base such as sulphide of
soda is added, first the copper, then the iron and finally the nickel take up sulphur
from it, and the lower sulphides existing in the "bottoms with the crude nickel
are converted into full sulphides. These higher sulphides coalesce with the soda
and form a mass which is very light. The lower sulphides of the metal do not so
coalesce and are precipitated to the bottom, and by repeating the operation all the
lower sulphides of iron and copper are converted into higher sulphides and are thus
separated from the lower sulphide of nickel.
If, now, the nickel sulphide settling in the bottom be separated by mechanical
means, or by hand and subjected to repeated treatment by smelting with sulphide
of soda, any number of times, the iron and copper may be still further separated,
and eventually a sulphide of nickel produced which is commercially pure.
A further part of this invention relates to the utilization of the by-products
produced in the above described operation of separating, as reagents or fluxes in
subsequent operations, of similar character for the purpose of effecting a cheaper
and equally efficient separation.
The tops resultant from the second step of the separation above referred to in
the aforesaid process or from the treatment of the "bottoms" from the first step
with sulphides of any of the alkaline bases, either as such or as produced by
smelting with nitre or salt cake with an excess of carbon as hereinafter described,
contain a large amount of caustic alkali.
By substituting these "tops" for the caustic alkalies or carbonates of any of the
alkaline bases referred to as the reagent used in the first step of the above described
process, it is possible to effect the separation equally efficiently and much more
cheaply, as an economical source of supply for the caustic alkali necessary to effect
such first step is thus provided.
In order to procure "tops
"suitable for use in this manner, it is sometimes
necessary to eliminate a considerable proportion of the iron by the ordinary
smelting process, for the reason that although this is in no wise essential for the
separation, nevertheless the resultant "tops" will, if the alkali is associated with
an excess of iron, not act as a proper reagent.
If desired, the "tops" containing the caustic alkali, can be allowed to weather,
i.e. to become exposed to the action of heat and rain, and thus the alkali will be
dissolved out of the "tops" by the water, leaving behind the sulphides of copper,
iron and nickel. By evaporating the alkali to such consistency as may be found

page_text: 56
convenient, and then charging it with the ore or mattes into the furnace, the “ tops '
may be used as before.
6:
19
In case sufficient caustic alkali cannot be obtained from the " tops " above
described, a portion of the mattes or ores to be treated in the first step of the
initial process may be smelted directly with a sulphide of any alkaline base, with
the difference that the "bottoms" will remain in the form of sulphides and the
tops so formed will then be found to contain sufficient caustic alkali to enable
them to be thereafter used, as a reagent in the first step of subsequent treatments
of other nickeliferous bodies. In each case the object sought to be obtained is to
effect the first step of the initial treatment of the mattes, as far as possible by
smelting the ores and mattes with caustic alkali, supplied from "tops" "resultant
from the second step of the previous treatment.
A further part of my invention relates to a method of supplying sulphide of soda
for use as a reagent in the second step of the above described initial process, as
sulphide of soda, being a substance which is not very often used except upon a small
scale, is difficult and expensive to procure.
When ordinary nitre cake or salt cake of commerce or other salt of soda and
sulphuric acid, as may be found most convenient, is charged into the furnace with
the crude nickel of the ."bottoms" resultant from the treatment with caustic
alkalies or carbonates of the alkaline bases, and preferably salt cake or nitre cake,
which contains an excess of free sulphuric acid, the sulphate of soda of the nitre or
salt cake, according to whichever be used, is, when treated in a cupola or blast
furnace in the presence of carbon, at once converted into sulphide of soda, which
unites with the crude metals, in the "bottoms," and the reactions above described
take place precisely in the same manner as before.
Salt cake or nitre cake can be readily procured at reasonable prices in many
localities, and the carbon is readily supplied by the fuel of the furnace.
When it is desired to repeat the separation by sulphide of soda, after described,
the "bottoms" resulting from the initial process, are again smelted with salt or
nitre cake in a shaft furnace, in the presence of carbon and the smelted mass
allowed to settle and is then separated as before.
A further part of the invention relates to a method of utilizing the by-products
of the final steps of the operation of separating above described, as reagents of
fluxes in subsequent operations of similar character for the purpose of effecting a
cheaper and equally efficient separation.
The "tops "resultant from the second step of the initial separation above referred
to, that is from the treatment of the “bottoms” from the first step of the initial
process with sulphide of soda, either as such, or as produced by smelting with nitre
or salt cake, with an excess of carbon, contain at first a large amount of caustic
soda, but as the second step, namely, the treatment with sulphide of any alkaline
base is repeated the " tops will be found to contain less caustic soda, and will
gradually become richer in sulphide of soda.
2"
Now, my correspondent has discovered that by substituting these "tops."
resultant from the final separations of the nickel sulphide in previous operations,
for the sulphide of the alkaline base, referred to as the reagent or flux used in the
second step of the above described process, it is possible to effect the separation
equally efficiently and much more cheaply, as an economical source of supply for
the sulphide of the alkaline base necessary to effect such second step is thus at once
provided.
In order to procure << tops" suitable for use in this manner, it is sometimes
necessary to eliminate a considerable proportion of the iron contained in the
nickeliferous body, by the ordinary smelting process, for the reason that although,
when such bodies containing considerable iron are treated with soda, the desired
separation is effected, nevertheless, the resultant " tops will, if the soda is
associated with an excess of iron, not act as a proper reagent in the subsequent
treatment of the other mattes.
"
The various smelting operations above described may be carried out in any

page_text: convenient form of furnace. The sulphide of nickel thus separated may be
subjected to further metallurgical treatment, and may be reduced to metallic nickel
and sold as such or it may be converted into oxide of nickel and sold, or sold
directly as sulphide, according to the purpose for which the nickel is required.
In practice, the amount of chemical re-agents added will vary from time to time,
in accordance with the nature and condition of the matte; but in practice it is
found that from thirty to fifty per cent. of the above described re-agents may be
mixed with the ores or other nickeliferous substances charged into the furnace.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
1. The hereinbefore described method of producing and separating nickel
sulphide, consisting in smelting the ores or mattes containing nickel, with caustic
alkalies, carbonates of the alkaline bases or a mixture thereof, or other similar
reagents rich in oxygen, substantially as set forth, whereby the nickel is converted
into crude metallic nickel, in allowing the crude nickel to settle and separate
by gravity, in separating the crude nickel after settling, and in resmelting the same
with an alkaline sulphide substantially as set forth, whereby nickel sulphide and
caustic alkali are produced, and in allowing the nickel sulphide to settle and
separate by gravity and separating the same after settling.
2. The hereinbefore described method of producing and separating nickel
sulphide, consisting in smelting the ores or mattes containing nickel, with caustic
alkalies or carbonates of the alkaline bases or a mixture thereof or other similar
reagents rich in oxygen, substantially as described, whereby the nickel is
converted into crude metallic nickel, in allowing the crude nickel to settle and
separate by gravity, in separating the crude nickel after settling; and in resmelting
the same, with a sulphide of an alkaline base whereby nickel sulphide and caustic
alkali are produced, in allowing the nickel sulphide to settle and separate by
gravity, in separating the same after settling and subjecting it to repeated smelting
with the sulphide of an alkaline base and separation by gravity, until the impurities
are eliminated and a residue of commercially pure sulphide of nickel is produced.
3. The method of producing sulphide of nickel from "bottoms resultant from
the initial treatment of nickel ores or mattes, with alkaline reagents substantially
as described, consisting in smelting the same with a sulphide of any alkaline base
of a mixture of any two or more of such sulphides, substantially as described,
whereby nickel sulphide and caustic alkali are formed, and in allowing the former
to settle and separate by gravity and removing the same after settling.
"
4. The herein before described method of producing crude nickel for use in the
production of nickel sulphide consisting in smelting ores, mattes or other bodies
containing nickel with the "tops" rich in caustic alkalies, produced from smelting
crude nickel with sulphides of any alkaline base of a mixture of any two or more
of the same or other reagents producing alkaline sulphides in previous operations.
5. The herein before described method of producing and separating crude nickel
for use in the production of sulphide of nickel consisting in smelting the ores, or
mattes, containing nickel with a concentrated alkali, produced by allowing the
tops resultant from the smelting of crude nickel with sulphides of any alkaline
base or any two or more of the same in previous operations to decompose by
exposure to the air, and then separating the insoluble portions, and in allowing the
nickel sulphide so formed to settle and separating the same after settling.
66
"
6. The herein before described method of producing and separating sulphide of
nickel, consisting in smelting the ore, mattes or other bodies containing nickel with
a suitable reagent of flux, substantially as set forth, whereby the nickel is converted
into crude metallic nickel in allowing the crude nickel to settle and separate by
gravity in separating the same after settling, and resmelting with nitre or salt cake
substantially as set forth, with an excess of carbon, whereby the nitre or salt
cake is decomposed and sulphide of soda formed, which unites with the crude

page_text: nickel to form nickel sulphide and in allowing the nickel sulphide to settle and
separate by specific gravity and in separating the same after settling.
7. The hereinbefore described method of producing sulphide of soda for use in
producing nickel sulphide from crude nickel, consisting in smelting the crude
nickel with commercial salt cake or nitre cake with an excess of carbon,
whereby the cake is decomposed, and sulphide of soda formed, which unites with
nickel to form nickel sulphide.
8. The hereinbefore described method of producing and separating sulphide
of nickel from crude nickel by smelting the same with commercial nitre cake
or salt cake or other similar soda salt in a furnace with an excess of carbon,
whereby the soda salt is decomposed and sulphide of soda formed, which unites
with the nickel to form nickel sulphide, and in allowing the latter to settle and
separate by specific gravity and in separating the same after settling.
9. The hereinbefore described method of producing sulphide of any of the
alkaline bases for use in processes for producing and separating sulphide of nickel
from crude nickel consisting in smelting the crude nickel in a suitable furnace with
"tops" rich in sulphides of any of the alkaline bases resultant from the final
separations of the sulphide of nickel in other similar operations.
10. The hereinbefore described method of producing and separating sulphide of
nickel consisting in smelting the ores, or mattes, containing nickel with suitable
reagents substantially as described, and in allowing the crude nickel so formed to
settle, in separating the same after settling in any convenient manner and in
smelting the same in a suitable furnace with "tops" rich in sulphides of any of
the alkaline bases resultant from the final separations of the sulphide of nickel in
previous similar operations, and in allowing the sulphide of nickel so formed to
settle and in separating the same after cooling.
Dated this 9th day of January 1893.
WM. P. THOMPSON & Co.,
Agents for the Applicant.