and its Separation from other Sulphates.
Year: 1887

page_text: Date of Application, 22nd June, 1887
Complete Left, 21st Mar., 1888
Complete Accepted, 20th Apr., 1888
and its Separation from other Sulphates.
We, WALTER NOEL HARTLEY, of 2, Tobernea Terrace, Monkstown, County
Dublin, Fellow of the Royal Society, Professor of Chemistry in the Royal College of
Science, Dublin, and WILLIAM EDMUND BRANDFORD BLENKINSOP, of Garden Wharf,
Church Road, Battersea, in the county of Surrey, Manufacturing Chemist, do hereby
declare the nature of this invention to be as follows:-
This invention relates to improvements in the manufacture or preparation of cobalt
sulphate and its separation from other sulphates which may be mixed therewith such
as the sulphates of copper, iron or zinc.
In carrying out this invention we mix together proper proportions of the artificial
or natural cobalt oxides and sulphur or "spent oxide" from gas-works or one of the
metallic sulphides such as pyrites, marcasite, galena, zinc blende or factitious pyrites ;
or polysulphides, thiosulphates and other compounds or mixtures of sulphur compounds
found in oxidised "tank waste" resulting from the manufacture of alkali by Le Blanc's
process and obtained from the waste by lixiviation.
The ores of cobalt most suitable for the purpose are such as contain considerable
proportions of cobalt oxide and which are free from arsenic.
In practice we take a suitable cobalt ore or a crude oxide of cobalt such as may be
obtained by suitable treatment of a cobalt ore and containing say forty per cent. of
cobalt oxide and for every ten parts of this material we take about five and a half parts
of sulphur or not less than twenty eight parts of pyrites containing forty five per cent.
of sulphur or an equivalent quantity of poorer pyrites. Both materials are finely
ground and thoroughly mixed. The mixture is then placed in a covered crucible or
upon the hearth of a reverberatory furnace and heated without free access of air to a
bright red heat as rapidly as possible until the particles just begin to agglutinate. The
temperature may then be allowed to fall to a dull red heat and air is admitted freely
which then causes the mass to burn with a bright glow. When the combustion
slackens the temperature of the furnace may be advantageously raised and maintained
LP 21

page_text: as long as it is possible that the materials will absorb oxygen. The mass is withdrawn
when oxidation no longer continues and is quenched by throwing it into water which
dissolves out the cobalt sulphate but leaves other oxides such as copper oxide, nickel
oxide, ferric oxide and basic nickel sulphate in an insoluble form.
The cobalt sulphate may be crystallised from the solution in water.
Instead of proceeding precisely in the manner described the cobalt oxide or a
suitable cobalt ore may be intimately mixed with powdered pyrites and calcined at
once at a bright red heat with a plentiful supply of air. In this way when all com-
bustion has ceased the cobalt sulphate may be extracted with water. We have also by
experiment found the following modifications of the process to give good results. We
take about twenty eight parts of quicklime or its equivalent in slaked lime and mix it
with about one hundred and forty parts of pyrites containing about forty five per cent.
of sulphur. The mixture is heated to bright redness without access of air in a covered
crucible whereby calcium sulphide is produced along with other sulphuretted com-
pounds. The material is easily powdered and mixed with about forty parts of cobalt
oxide. It is then heated to bright red heat with free access of air by which means
the sulphides of iron, cobalt and calcium are converted into ferric oxide, cobalt
sulphate, and calcium sulphate respectively. The cobalt sulphate is separated from the
ferric oxide and the bulk of the calcium sulphate by treatment with hot water. Or
the cobalt oxide is mixed directly with pyrites and lime in the proportions already
mentioned and the whole is heated to bright redness in a closed cruciole and afterwards
calcined.
"
Instead of using a previously heated mixture of lime and pyrites we may make use
of "tank waste **
or gas lime" mixed with pyrites and add the cobalt oxide thereto.
The presence of lime appears to act advantageously upon certain ores or forms of
cobalt oxide. They become sulphuretted more readily and are oxidised with facility
by calcination into sulphates. The use of "tank waste" which consists largely of
calcium sulphide effects a saving in the sulphur of the pyrites.
In
Or we take strontia or baryta instead of lime, or we reduce the sulphate of lime,
strontia or baryta to the state of sulphide by any well known process and we use this
when more convenient to do so in the place of lime or of "alkali waste."
substituting these different materials for lime it is advisable to make an increase in
the proportions used in accordance with the increase in the chemical equivalents of
the substances.
Furthermore we have found that when about 200 parts of zinc blende in fine powder
are mixed with 75 parts of cobalt oxide and the mixture is calcined at a bright red
beat but not too strongly there is an abundant yield of cobalt sulphate. It is separated
by treatment with water. If the mass turns green then the teinperature is too high.
When 470 parts of galena in powder are mixed with 75 parts of cobalt oxide and
calcined in like manner practically pure cobalt sulphate can be extracted from the
mass with water.
We have also found that when zinc sulphate is heated strongly with cobalt oxide it
becomes converted into cobalt sulphate and zinc oxide. We make use of this reaction
to purify the cobalt sulphate made by calcining zinc blende from any zinc sulphate
which it may contain by adding thereto some cobalt oxide and heating until the dried
mass intermixes and becomes purple. The mass is then treated with water and the
zinc oxide is separated.
G. F. REDFERN,
4, South Street, Finsbury, London,
Agent for the Applicants.

page_text: and its Separation from other Sulphates.
We, WALTER NOEL HARTLEY, of 2 Tobernea Terrace, Monkstown, County Dublin,
Fellow of the Royal Society, Professor of Chemistry in the Royal College of Science,
Dublin, and WILLIAM EDMUND BRANDFORD BLENKINSOP, of Garden Wharf, Church
Road, Battersea, in the County of Surroy, Manufacturing Chemist, 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 :-
--
This invention relates to improvements in the manufacture or preparation of cobalt
sulphate and its separation from certain other sulphates which may be mixed therewith
such as the sulphates of lime, iron, copper or zinc.
In carrying out this invention we mix together materials containing the artificial
or natural cobalt oxides or sulphides with proper proportions of sulphur, "spent
oxide" from gas works or one of the metallic sulphides such as pyrites, marcasite,
galena, zinc blende or factitious pyrites or polysulphides, thiosulphates and other
compounds or mixtures of sulphur compounds found in oxidised "tank waste
resulting from the manufacture of alkali by Le Blanc's process and obtained from the
waste by lixiviation.
"
The ores of cobalt most suitable for the purpose are such as do not contain much
arsenic but do contain oxide or sulphide of cobalt or of cobalt and nickel in large or
small quantities.
The artificial products most suitable are cobalt oxide or sulphide, mixed oxides
and mixed sulphides containing cobalt or a mixture of oxides and sulphides.
We have performed the operation upon Spanish cobalt ores containing oxide of
cobalt upon manganiferous cobalt ores and nickeliferous pyrites containing cobalt.
In practice we take a suitable cobalt ore or crude oxide of cobalt such as may be
obtained by a suitable treatment of a cobalt ore and, for every ten parts of the metallic
oxides it contains, we take about five and a half parts of sulphur or not less than
twenty eight parts of pyrites containing forty-five per cent. of sulphur or an equivalent
quantity of poorer pyrites. Both materials are finely ground and thoroughly mixed.
The mixture is then placed in a covered crucible or upon the hearth of a reverberatory
furnace and heated with as little access of air as possible to a temperature at or about
the melting point of zinc but below that of antimony. If the mass begins to agglutinate
the temperature may be allowed to fall to a barely perceptible red heat and air be
admitted freely.
The admission of air causes the mass to burn. When the combustion becomes so
slack that the mass no longer burns when stirred the temperature of the furnace may
be advantageously raised and maintained as long as it is possible that the materials
will absorb oxygen. The mass is withdrawn when oxidation no longer continues and
allowed to cool. If the ore contains gangue, lime, iron or alumina, the temperature
of the furnace prevents the formation of the sulphates of iron and alumina. On
treating the mass with water the cobalt sulphate gradually dissolves leaving the

page_text: sulphate of lime for the most part insoluble. The solution may be evaporated and the
cobalt sulphate crystallised.
Instead of proceeding precisely in the manner described the cobalt oxide or a
suitable ore of cobalt is intimately mixed with powdered pyrites and calcined
at once with a plentiful supply of air. The temperature may rise to the melting point
of zinc.
We have also found the following modifications of the process to give good results.
We take about twenty eight parts of quicklime or its equivalent in slaked lime and
mix it with about one hundred and forty parts of pyrites containing about forty five
per cent. of sulphur. The mixture is heated to bright redness without access of air
in a covered crucible whereby calcium sulphide is produced along with other
sulphuretted compounds. The material is easily powdered and mixed with about
forty parts of cobalt oxide. It is then heated to a red heat with free access of air by
which means the sulphides of iron, cobalt and calcium are converted into ferric oxide,
cobalt sulphate, and calcium sulphate respectively. The cobalt sulphate is separated
from the ferric oxide and the bulk of the calcium sulphate by treatment with hot water.
Or the cobalt oxide is mixed directly with pyrites and lime in the proportions already
mentioned and the whole is heated to redness or about the melting point of zinc in a
closed crucible and afterwards calcined.
Instead of using a previously heated mixture of lime and pyrites we may make use
of "tank waste" (6
or gas lime" mixed with pyrites and add the cobalt oxide thereto.
The presence of lime appears to act advantageously upon certain ores or forms of
cobalt oxide. They become sulphuretted more readily and, by calcination, are
oxidised with facility into sulphates. The use of "tank waste" which consists largely
of calcium sulphide effects a saving in the sulphur of tho pyrites.
In
Or we take strontia or baryta instead of lime, or we reduce the sulphate of lime,
strontia or baryta to the state of sulphide by any well known process and we use
this when more convenient to do so in the place of lime or of alkali waste."
substituting these different materials for lime it is advisable to make an increase in the
proportions used in accordance with the increase in the chemical equivalents of the
substances.
Furthermore we have found that when about two hundred parts of zinc blende in
fine powder are calcined at about the melting point of zinc but below that of antimony
there is an abundant yield of cobalt sulphate. If the mass turns green the temperature
is too high. The cobalt sulphate is separated by treatment with water. We have
also found that when zinc sulphate which may be obtained by calcining blonde is
heated strongly with cobalt oxide it converts it into cobalt sulphate and becomes zinc
oxide.
We have made use of this reaction to purify the cobalt sulphate from zinc sulphate
which it may contain by moistening with water and adding thereto some cobalt oxide.
Heat is applied until the mass dries and subsequently at a red heat intermixes and
becomes purple. The mass is then heated with water which separates the cobalt
sulphate from the zinc oxide.
We find also that both cobalt hydrate and cobalt carbonate when precipitated from
a solution of a cobalt salt have the property of precipitating zine hydrate and zinc
carbonate from solutions of zinc sulphate. We make use of this reaction to separate
zinc from cobalt sulphate. We add a quantity of either cobalt hydrate or carbonate
to the solution of cobalt sulphate sufficient to precipitate all the zinc as hydrate or
carbonate and boil until it is found on filtering the liquid that no more zinc remains
in solution, or that no more cobalt bydrate will enter into solution. The purified
cobalt sulphate is then filtered from the insoluble zinc compound and crystallised by
evaporation.
Or instead of adding cobalt hydrate or carbonate to the solution we add a quantity
of sodium carbonate sufficient to precipitate all the zinc, that is to say, for every
80 parts by weight of zinc oxide to be removed we add 106 parts of anhydrous sodium
carbonate. The solution is then boiled until the precipitate easily settles down in the
solution on standing.

page_text: If an ore containing much iron and manganese in the form chiefly of peroxides
contains only a small proportion of cobalt or mixed cobalt and nickel as oxides or
sulphides we disregard the iron and add the quantity of pyrites necessary to convert
the manganese and cobalt oxides into sulphates, and proceed as if the oro was pure
cobalt oxide. The solution obtained is boiled with the sulphide or oxysulphide of
manganese in the manner described in our Complete Specification, No. 6029 of 1887
and the cobalt and nickel are precipitated as sulphides. The sulphides are separated
and calcined with pyrites to obtain sulphates free from manganese.
When about 470 parts of galena in powder are mixed with about 75 parts of cobalt
oxide and calcined at a temperature about that of melting zinc practically pure cobalt
sulphate is obtained by treating the mass with water.
In the treatment of ores of cobalt containing copper as well as manganese, the copper
is first precipitated from the solution of the sulphates by metallic iron and cobalt,
sulphide is then thrown down by the addition of manganese sulphide or oxysulphide
to the solution. The cobalt sulphide, which may have more or less ferrous sulphide
precipitated with it, is roasted at a temperature below redness say at about the melting
point of lead until the black cobalt sulphide becomes, to a great extent, converted into
a purple or pink anhydrous sulphate. The cobalt sulphate is extracted by boiling with
water. Any residue containing cobalt is then fired with pyrites in the manner already
described. Or having ascertained the usual amount of residue left after roasting the
cobalt sulphide, the requisite quantity of pyrites to convert this residue into sulphato
is added at once to the cobalt sulphide and the mixture is then fired.
We do not restrict ourselves to employing the proportions of pyrites and cobalt
oxide hereinbefore stated because the nature of the ores is subject to such variations
that a smaller proportion of pyrites would in some cases be sufficient especially if the
ore itself contained pyrites.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what we
claim is :-
1. In the manufacture or preparation of cobalt sulphate, the use of a mixture
containing for the one part an ore or other material containing oxide of cobalt or
sulphide of cobalt, mixed or not with other metallic oxides or sulphides, and for the
other part of a metallic sulphide such as iron pyrites or any sulphide or sulphurised
material capable of yielding sulphurous acid gas when heated in air or of yielding
sulphur when heated in a closed vessel, substantially as described.
2. The process described for the separation of cobalt sulphate from other sulphates.
Dated the 21st day of March 1888
G. F. REDFERN & Co.,
4, South Street, Finsbury, London,
Agents for the Applicants.