IMPROVEMENTS IN TREATING CERTAIN ORES AND ALLOYS, AND IN OBTAINING PRODUCTS THEREFROM, AND IN RECOVERING OR REPRODUCING ALL OR PART OF THE MATERIALS USED
Year: 1857

page_text: LETTERS PATENT to William Henderson, of Bristol, Chemist, for the
Invention of "IMPROVEMENTS IN TREATING CERTAIN ORES AND ALLOYS, AND
IN OBTAINING PRODUCTS THEREFROM, AND IN RECOVERING OR REPRODUCING ALL
OR PART OF THE MATERIALS USED."
Sealed the 20th March 1858, and dated the 30th September 1857.
PROVISIONAL SPECIFICATION left by the said William Henderson at
the Office of the Commissioners of Patents, with his Petition, on the
30th September 1857.
1, WILLIAM HENDERSON, of Bristol, Chemist, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN TREATING CERTAIN ORES AND
ALLOYS, AND IN OBTAINING PRODUCTS THEREFROM, AND IN RECOVERING OR REPRO-
DUCING ALL OR PART OF THE MATERIALS USED," to be as follows:-
These improvements relate, first, to the treatment of copper and some other
metals when they occur in the state of carbonates or oxides in ores con
taining much silica.
Secondly, to the treatment of ores of copper and several other metals when
they occur in the state of sulphurets combined with iron.
Thirdly, to the treatment of certain alloys of copper and tin called "white
inetal."
The first class of ores 1 treat in the following manner:-The ore is crushed
and introduced into tanks or vats made of wood, stone, or other suitable
material. Muriatic acid sufficient to cover the ore is also introduced.
[Price 8d.]
If

page_text: the ore is poor and consists of a loose friable rock, the acid may be very
weak, and at ordinary temperature be used cold. For a 24 per cent. copper
ore, acid of from 1.025 to 1.050 answers very well. The richer the ore the
acid will generally be required stronger. The exceptions I will explain
hereafter. To economize acid and obtain a solution of uniform strength,
the vats are worked in a similar manner to the black ash vats commonly
in use in alkali works.
Having obtained a clear solution of the metals which if they existed in the
ore, may be copper, iron, lead, and several other metals of more rare occurrence.
To separate the iron and lead, I first ascertain if the iron is in the state of
peroxide, if not, it is brought to that condition by passing a stream of chlorine
through the solution boiling, or any other means most convenient. Carbonate
of lime in powder is then added to the cold solution, and the whole well
agitated; the carbonate of lime must be slightly in excess. This will precipitate
all the iron and lead. The mixture is allowed to settle, and the clear green
solution of copper,after being drawn off into another vessel, is then treated with
caustic lime very slightly in excess. This precipitation is most economically
and expeditiously effected at a boiling heat. Finely powdered carbonate of
lime at a boiling heat will also precipitate copper from the above solution,and
so will carbonate of barytes, or sulphuret of barytes, prepared by heating
common heavy spar to bright redness in powder with carbonaceous matter,
as also carbonate or sulphuret of strontian prepared in the same manner,
carbonate of magnesia or lime made from magnesian limestone, or lastly,
the sulphuret of lime waste from the manufacture of alkali. But when the only
object in view is the obtaining the copper precipitate as rich as possible, and
where the prices are equal, I prefer caustic lime or ground limestone. When
convenient I also use scrap iron for precipitating the copper. The result
of the use of any of the above precipitants is the production of a hydrate
of oxide of copper, carbonate of copper, sulphuret of copper, or metallic
copper precipitate, as the case may be, and a solution of chloride of the
metal or alkaline earth that has been used as a precipitant.
The precipitate, after washing and drying, is sinelted for copper in the
usual manner. The solution of chloride of calcium, magnesium, barium, or
strontian, or a mixture of either, I concentrate by evaporation. If it is only
desired to recover the muriatic acid contained in these salts, it is most com-
pletely and expeditiously done in the following manner:-In a common rever-
beratory furnace with the bottom made concave towards the middle, and two
exit flues, one communicating with the stack and the other with a stone
tower or condenser of the same description as those in common use for con-

page_text: densing muriatic acid, the damper leading to the condenser being closed,
about 2 tons of sand; or the insoluble matter from the ore is brought tobright
redness, and then the damper leading to the stack closed and the other
opened. A small stream or shower of the boiling and highly concentrated
chloride solution is then allowed to play upon the red hot sand, the work-
man all the while thoroughly mixing and incorporating them together. The
heat must never be allowed to fall below dull redness. By this means the
chlorides of the alkaline earths are completely decomposed, and nearly all
the muriatic acid reproduced and reobtained fit for use.
If it is also desired to obtain the bases as well as the acid, I proceed as
follows: The solution of the chloride or chlorides is evaporated to complete
dryness, then transferred to the reverberatory furnace and melted, the damper
leading to the stack is then closed and the other opened, and a jet of steam
(superheated steam by preference) is blown down into and through the molten
mass, and is continued until no more muriatic acid gas is given off. To
complete the entire decomposition of the chlorides, and especially chloride
of calcium, the addition of a little red-hot sand or siliceous matter towards
the close of the operation is desirable. If iron has been used as a pre-
cipitant, the decomposition of the chlorides cannot be effected in the same
way, owing to the exceeding volatility of the perchloride. To obtain the
muriatic acid from the chlorides of iron, the solution must be gently
evaporated to dryness, and slowly calcined in a close calcining furnace
similar to the one described in my Specification, dated 14th July 1853, with
a current of low-pressure steam passing over it, and constant stirring. By
this means the chlorides of iron may be entirely decomposed.
To produce Epsom salts, I proceed as follows:-The solution of chloride
of magnesium having been obtained in the manner described, I evaporate to
dryness, and introduce the dry salt into a cast-iron pan heated below, domed
over with brickwork, and commonly known under the name of "a balloon."
and used in alkali works for the decomposition of common salt. The dry
chloride of magnesium having been introduced into this apparatus, is treated
with sufficient strong sulphuric acid to exactly effect its decomposition. This
is performed in exactly the same manner as in the case of common salt. The
result of this operation is the production of anhydrous sulphate of magnesia.
This salt is dissolved in water, and the saturated solution run off to crystallize
into to the commercial Epsom salts. When for precipitating the copper and
other metals, a salt, or compound of barytes has been used, and consequently
a chloride of barium been produced, I prepare on the one hand a very pure
enamel white or sulphate of barytes, and on the other recover the muriatic

page_text: acid fit for further use by the following process:-To the solution of chloride
of barium previously concentrated, strong sulphuric acid is added, which
precipitates all the barytes as a pure white sulphate, and leaves the muriatic
acid as the supernatant liquor. This may be run off to redissolve fresh ore,
and the precipitant of sulphate of barytes when well washed and pressed is
fit for the market. When ores of this class contain, besides iron, copper,
and lead, oxides of cobalt and nickel, this is accomplished by either of the
two following processes :-
1. When the copper exists in the state of carbonate or oxide, and the
cobalt or nickel in the state of oxide in the ore, I first crush the ore into
coarse powder, and treat with cold muriatic acid of from 1:025 to 1.075 sp. gr.
according to the richness of the ore in copper, as has already been de-
scribed. The clear green solution which will only contain iron and copper,
is treated with carbonate of lime, first to separate iron and then afterwards
with caustic lime or any of the other precipitants previously mentioned, to
obtain copper
in the state and manner previously described. The insoluble
matter left in the vats, after treatment with the weak muriatic acid, contains
all the nickel or cobalt, and some iron. To obtain these metals in solution,
I boil the insoluble matter in strong muriatic acid, run the solution off, and
allow it to cool. The cold solution is then treated with carbonate of lime to
separate iron, and afterwards by caustic line, which precipitates all the cobalt
or nickel as hydrated oxides. The precipitate after being well washed is
heated to bright redness, and is then pure oxide of nickel or cobalt, or a
mixture of both.
2ndly When the ores containing cobalt or nickel contain sulphur, I
submit them, after crushing, to complete calcination, and dissolve at once to
strong muriatic acid and heat. After peroxidizing the iron, if necessary, I
allow the solution to cool, and then treat with carbonate of lime to separate
iron, lead, &c.
I then draw off the clear supernatant liquor into another
vessel, and apply heat and carbonate of lime: by this means the whole of the
copper will be precipitated as carbonate, and the nickel and cobalt, or both
will be left in solution, and after drawing off the liquor into another vessel
may be precipitated by caustic lime. I may here mention that I do not con-
fine myself to the use of carbonate of lime and caustic lime, but wherever
carbonate of lime is mentioned carbonate of any of the other alkaline earths
may be used instead, and wherever caustic lime is mentioned, any of the other
alkaline earths, either in the caustic state or as soluble sulphurets, may be
used, or the insoluble sulphuret of lime, called alkali waste, will answer the
same nurnose.

page_text: The ores of the second class, namely those containing besides the metals
a proportion of sulphur, I proceed with as follows:-The ores are first roughly
crushed and thoroughly calcined, and then reduced to coarse powder. If much
lead exists in the ore, it is first necessary to boil the ore with sufficient weak
sulphuric acid to convert the lead into sulphate, the ore is then heated to dull
redness and treated with muriatic acid of about 1-075 sp. gr. assisted by
steam heat. All the lead and greater portion of the iron will remain undis-
solved, and the copper and other metals obtained in solution as chlorides.
This solution is treated exactly as that obtained from the first class of ores.
The alloys of copper and tin, I treat in the following manner :-I take
the alloy called "white metal," and sometimes obtained as a bye-product in
the smelting of copper, and I reduce it to fine powder. The unrefined metal
I prefer, as it is easier to crush. The powder so obtained, I place on the top
bed of a double calcining furnace, and gradually raise to bright red heat,
stirring well all the while. Great care must be taken at the beginning of the
operation to prevent the alloy melting, after a short time, however, the oxides
formed prevent this, and with care in 6 hours it may be raised to a full red
heat without danger. When the alloy has been throughly oxidized, it is
withdrawn from the furnace and gradually introduced with constant stirring
into a vessel containing dilute sulphuric acid. By this means the whole of the
copper is dissolved, and may be crystallized as sulphate, whilst the tin will be
found at the bottom of the vessel as oxides, and is then easily reduced to
the metallic state in the ordinary manner.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Henderson in the Great Seal Patent Office on
the 30th March, 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HENDERSON, of Bristol, Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirtieth day of September in the year of our Lord
One thousand eight hundred and fifty-seven, in the twenty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said William Henderson, Her special licence that I, the said William
Henderson, my executors, administrators, and assigns, or such others, as
I, the said William Henderson, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and at all

page_text: times thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention
for IMPROVEMENTS IN TREATING CERTAIN ORES AND ALLOYS, AND IN OBTAINING
PRODUCTS THEREFROM, AND IN RECOVERING OR REPRODUCING ALL OR PART OF THE
MATERIALS USED," upon the condition (amongst others) that I, the said
William Henderson, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and scals, should par-
ticularly describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Henderson, do hereby
déclare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and by
the following statement thereof, that is to say:-
My Invention relates, first, to the treatment of copper and some other
metals, when they occur in the state of oxides, carbonates, arseniates, phos-
phates, or other insoluble salts or mixtures of these oxides and salts, in ores
containing a large proportion of silica, say, upwards of forty per cent.
Second, to the treatment of ores of copper and several other metals,
when they occur in the state of sulphurets combined with iron, and a large
proportion of silica, say, upwards of thirty per cent.
2
"
Third, to the treatment of certain alloys of copper and tin, called "white
metal."
Fourth, to the utilization of the waste chloride solutions produced during,
or resulting from, the above-named operations. The first class of ores I
treat in the following manner:-
The ore is crushed and introduced into tanks or vats, made of stone, wood,
or other suitable material. When carbonates are being worked, the depth of
ore in the vats may exceed three feet; but when oxides, arseniates, and phos-
phates are the ores operated upon, the above depth of ore should not be
exceeded. The vats should all have loose perforated false bottoms, resting on
cross bearers. To prevent the ore passing through the false bottom, a layer
of brush wood and coarse straw, or other suitable material should be placed
over it. The crushed ore is then introduced, and should be made to fill the
vat to within a few inches of the top. Muriatic acid sufficient to cover the
ore is poured on the surface, and allowed to work downwards through the
mass. A pump or other like mechanical agent, made of suitable materials, is

page_text: fixed in the vat, and reaches below the false bottom. As the liquor filters
downward it is frequently pumped up again to the surface, and a constant
circulation is thus maintained until the acid is saturated. To economize the
acid, and obtain a uniform strength of liquor, the vats should be worked in
sets of four or more. When the acid hias taken up as much metal as possible
the ore is washod perfectly clean, and the insoluble matter removed. When
the ore is poor, and consists of a loose friable rock, such as sandstone, the
acid may, , if convenient, be used very weak, and in ordinary weather cold.
Generally, a temperature of 100° Fahrenheit, and the acid as strong as
possible, answers best for muriatic acid solutions.
Having obtained a clear saturated solution of the metals which, if they
existed in the ore may be copper, iron, lead, and several other metals of more
rare occurrence, I proceed as follows:-I first ascertain if iron exists in the
solution in the state of peroxide, if not, it is brought to that state by chlorine
or by any other means. Carbonate of lime, in fine powder, is then added to
the cold solution, and the whole is well agitated. The carbonate of lime
should be slightly in excess; iron, lead, and several other oxides are pre-
cipitated. The mixture is allowed to settle, and the clear green solution, after
being drawn off into another vessel, is treated with caustic lime, very slightly
in excess, which will precipitate all the copper. This precipitation is most
economically and expeditiously effected at a boiling heat. Firely powdered
carbonate of lime, at a boiling heat, will also precipitate copper, aud so will
carbonate of barytes, or sulphuret of barium, carbonate and sulphuret of stron-
tian, carbonate of magnesia, or lime made from magnesian limestone, or lastly,
the sulpheret of lime waste from the manufacture of alkali. But when the
only object in view is the tof obtaining the copper precipitate as rich as possible,
and where the prices are equal, I prefer caustic lime. When the ores contain
a large proportion of oxide of iron, and especially when it exists as protoxide,
and no lead exists in the solution, it will be more economical to use scrap
iron to precipitate the copper at once from the original solution.
The result of the use of any of the above precipitants is, the production of
a hydrate of oxide of copper or other metal, carbonate, sulphuret, or metallic
precipitate, as the case may be, and a solution of chloride of the metal or
alkaline earth which has been used as a precipitant.
The precipitate, after washing and drying, is smelted for the métal in
the usual way.
When the ore under treatment is a phosphate or arseniate of copper, the
above process must be slightly varied. The vats should be worked as hot as
is possible without loss of muriatic acid. The solution after being run off is

page_text: allowed to cool, and then neutralized by carbonate of lime or other alkaline
earth; chloride of calcium or other alkaline earth is then added, as long as a
precipitate falls. Phosphoric and arsenic acids are thus completely separated
as insoluble phosphates or arseniates of the alkaline earths. The supernatant
copper solution then be run off and precipitated by any of the methods
already described.
may
When only phosphates of copper, iron, and some other metals, and no free
oxides exist in the ore, I take the raw muriatic acid solution as it comes from
the vats, and evaporate to complete dryness in connection with a condenser,
and I thus volatilize all the muriatic acid, and leave as a residue the phosphates
of copper, iron, &c. These I decompose, either by boiling or fusing with caustic
or carbonate alkali, and after dissolving the fused mass I obtain as a residue
the oxide or oxides of the metal or metals, and a soluble phosphate of the
alkali used. Sulphuric acid may also in some cases be employed for dissolving
the phosphates of copper, &c. in the vats, but in that case the liquor must only
be evaporated until a pellicle forms on the surface, and then be run off to
crystallize. I find, however, that the sulphates of copper and phosphates of
copperdo not readily separate, and for this and other reasons I prefer muriatic
acid.
.
I concentrate the solutions of chloride of calcium, magnesium, barium, or
strontian, or a mixture of either, by evaporation. If it is only desired to
recover the muriatic acid contained in these salts, and it is most completelyand
expeditiously effected by one or other ofthe following methods:-In a common
reverberatory furnace, with the bottom made concave towards the middle, and
two exit flues, che communicating with the chimney and the other with a
stone tower or condenser, of a similar description to those in common use for
condensing muriatic acid. The damper leading to the condenser being closed,
and the other opened, about two tons of sand, or the insoluble matter from
the ore is brought to a bright red heat, and then the damper leading to the
chimney closed and the other opened. A small stream or shower of the boiling
and highly concentrated chloride solution is then allowed to play on the red-
hot sand, the workmen all the while thoroughlymixing and incorporating them
together. The heat must never be allowed to fall below dull redness, nor must
too large a stream of liquor be introduced on the sand. By attention to these
precautions it will be found that a silicate of lime or other alkaline earth has
been produced in the furnace, and muriatic acid gas evolved, which passing
into the tower is condensed in the usual inanner, and is then fit for further use
in treating fresh ore. If it is also desired to obtain the bases as well as the
acid, I proceed as follows;-The solution of the chloride or chlorides is evapo

page_text: rated to dryness, and introduced into the reverberatory furnace and fused
;
the damper leading to the chimney is then closed and the other opened, a jet
of steam (superheated by preference) is blown down into and through the
molten mass, and is continued until no more muriatic acid gas is given off.
If iron has been used as a precipitant the decomposition of the chlorides
cannot be effected in the same manner, owing to the exceeding volatility of
the perchloride. To obtain the muriatic acid from the chlorides of iron, the
solution must be gently evaporated to dryness, and slowly calcined in a close
calcining furnace, similar to that described in the Specification of a
Patent granted to me, and dated Fourteenth July, One thousand eight
hundred and fifty-three, with a current of damp steam passing over it, the
salt being constantly stirred. By this means the chlorides of iron may be
entirely decomposed.
To produce Epsom salts I proceed as follows:-The solution of chloride
of magnesium having been obtained in the manner described, I evaporate
to dryness, and introduce the dry salt into a cast-iron pan, heated below and
domed over with brick, and commonly known under the name of a balloon,
and used in alkali works for the decomposition of common salt. The dry
chloride of magnesium having been introduced into this apparatus, is treated
with sufficient strong hot sulphuric acid as will effect its decomposition; this
is performed in the same manuer as in the case of common salt, and the
muriatic acid is obtained and condensed also in the same manner. The
anhydrous sulphate of magnesia thus produced is dissolved in water, and the
saturated hot solution run off to crystallize into the commercial Epsom salts.
When a salt or compound of barytes has been employed as the precipitant,
and consequently chloride of barium has been produced in solution, I conceu-
trate the solution to near saturation, and then treat the solution with sufficient
strong sulphuric acid to precipitate all the barytes as sulphate. I thus obtain
the muriatic acid in solution and enamel white as the precipitate, which when
washed and pressed is fit for the market.
When ores of this class contain, besides copper, iron and lead, oxides of
cobalt, nickel, and uranium, the separation of these metals is accomplished
by either of the two following processes :-
1st, when no sulphur exists in the ore, I crush it to a coarse powder, and
treat with cold muriatic acid of from 1.025 to 1-075 sp. gr., according to the
richness of the ore in copper and iron, as has already been described. The
clear green solution, which will only contain copper and iron and sometimes
lead and uranium, is treated with carbonate of lime. If uranium exists in the
ore, the agitation ought to be continued for a long time, and the precipitate
:

page_text: be allowed to settle for forty-eight hours; any iron peroxide and lead and
uranium will be found all precipitated. To separate the uranium I digest the
precipitate in bicarbonate of soda, or potash or carbonate of ammonia, and
then from the filtered solution obtain the uranium by boiling and neutralizing.
After precipitating the iron, &c. the copper may be separated by caustic lime,
or any of the other precipitants, as has been already described.
The cobalt or nickel or both left in the ore are dissolved by boiling the
residual ore with strong muriatic acid. The solutions of chloride of cobalt
or nickle thus obtained are treated in the usual manner.
"
2nd, if the ores of the above class contain sulphur, they are first calcined
and treated in a similar manner. I may here mention that I do not confine
myself to the use of carbonate and caustic lime, but whenever carbonate of
lime is mentioned, carbonate of any of the other alkaline earths may generally
be used, and in place of caustic lime, either of the alkaline earths in the
caustic state, or as soluble sulphurets may be used, or the insoluble sulphuret
of lime, called alkali waste, may be employed in some cases.
The ores of the second class, viz. those containing sulphur are first roughly
crushed and thoroughly calcined and then reduced to coarse powder., When
the ores contain much lead it is first necessary to treat them with sufficient
weak sulphuric acid to convert the lead into sulphate, the mass is then
evaporated to dryness and heated to dull redness, then withdrawn from the
furnace and treated in a vat with muriatic acid of about 1.075 specific
gravity. The vat being kept hot by steam, all the lead and the greater
portion of the iron will remain insoluble, the copper and other metals will
be obtained in solution as chlorides; these chlorides may be treated as
has been already described.
I treat the alloys of copper and tin in the following manuer :-I take the
alloy called white metal, and sometimes obtained as a bye-product in the
smelting of some kinds of copper ores, and I reduce, it to fine powder, I
prefer the unrefined metal as it is easier to crush. I place the powder so
obtained on the top bed of a double calcining furnace, and gradually raise to
a bright red heat, stirring well all the while. Great care must be taken at
the beginning of the operation to prevent the alloy melting. After a short
time, however, the oxides formed prevent this, and with care in six hours it
may be raised to a full red heat without danger. When the alloy has been
thoroughly oxidized it is withdrawn from the furnace, and gradually introduced
with constant stirring into a suitable vessel containing dilute sulphuric acid,
and heated by steam. When the solution has been thoroughly saturated, it is
boiled and covered up, and allowed to settle down clear; the solution is then

page_text: run off to crystallize into sulphate of copper, or may be precipitated as metallic
copper with formation of sulphate of iron, as is well understood. The white
or cream-colored sediment in the bottom of the dissolving vessel after being
washed will be found to be the pure oxides of tin, which may be reduced to
metallic tin inthe usual manner. If the sediment of oxides of tin is not at,
least of a pale yellow colour, it
must be calcined again, and the other
operations also repeated until it is entirely free from copper.
And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that I claim,-
First, the extraction of copper, lead, tin, zinc, and some other metals of
more rare occurrence, when they exist alone or mixed as oxides, carbonates,
phosphates, arseniates, and all other varieties of these salts or oxides,
insoluble in water or only partially so, by the means and in manner herein-
before particularly described.
Secondly, the several methods herein-before described of treating the
crude solutions of the metals, herein-before particularly mentioned, in
order to obtain products therefrom.
Thirdly, the reproduction of the muriatic acid employed in the extraction
of metals, by decomposing the chlorides by the several methods described.
Fourthly, the utilization of the bases by the means and methods described.
Fifthly, the production of the several commercial salts and products in
connection with the extraction of copper from the ores mentioned.
Sixthly, the method described for separating the copper and tin contained
in alloys of these metals, and the manufacture of sulphate of copper,
stannic acid, and oxide of tin from the bye-product called white metal.
And lastly, the extraction of copper from the phosphates, arseniates,
oxides and carbonates of that metal when they occur in sandstone or other
silecious rocks by means of muriatic acid.
In witness whereof, I, the said William Henderson, have hereunto set
my hand and seal, this Thirtieth day of March, One thousand eight
hundred and fifty-eight.
W. HENDERSON (L.B.)