IMPROVED PROCESSES FOR PURIFYING LEAD AND EXTRACTING AND SEPARATING SILVER THEREFROM AND IN MACHINERY FOR THOSE PURPOSES
Year: 1862

page_text: LETTERS PATENT to Arthur Wall, of Canton Street, East India Road,
Poplar, in the County of Middlesex, for the Invention of "IMPROVED
PROCESSES FOR PURIFYING LEAD AND EXTRACTING AND SEPARATING SILVER
THEREFROM AND IN MACHINERY FOR THOSE PURPOSES"
Sealed the 28th April 1863, and dated the 4th November 1862.
PROVISIONAL SPECIFICATION left by the said Arthur Wall at the
Office of the Commissioners of Patents, with his Petition, on the 4th
November 1862.
I, ARTHUR WALL, of Canton Street, East India Road, Poplar, in the
County of Middlesex, do hereby declare the nature of the said Invention for
"IMPROVED PROCESSES FOR PURIFYING LEAD AND EXTRACTING AND SEPARATING
SILVER THEREFROM, AND IN MACHINERY FOR THOSE PURPOSES," to be as follows:-
This Invention consists in the application of electricity or electric currents
as hereinafter described to the purification of lead and separation of silver
therefrom. Thus, for example, I take crude lead, or lead containing silver,
or other metals or impurities, such as arsenic, phosphorous, or other ingredients
and melt them in a pan or iron cylindrical vessel suitable for the purpose, and
when in a fit state of fusion I convey it through a pipe having a stop-cock
to another cylindrical iron vessel placed at a lower level, where it undergoes
the first process of separation and purification, and from thence I convey it.
through another pipe having a stop-cock, to a third or more similar cylindrical
vessels, where the process is completed, after which the lead is allowed to run.
through out of another pipe having a stop-cock to form ingots of purified lead
while the silver with the scoria or alloys are either previously skimmed off or
allowed to remain in the pans, when the latter is the case the fire is raised and

page_text: all the lead fusible in the scoria or alloys is separated from them and set apart
as silver lead. The apparatus or machinery I use for this purpose consists
of three or more cylindrical vessels made of copper, iron, or other metal or
material suitable for the purpose of melting lead. The first I use is a melting
cylinder whose capacity may be of any convenient size, and capable of holding
more or less from a few pounds weight to one or more tons of fused metal
the other two pans or cylinders which are placed each in a level lower to the
other by some inches or even feet are considerably smaller, and these I use
for purifying and extricating the silver from the lead. These latter have
placed over them and on each side of them, and sunk into the earth strong
posts for the purpose of supporting a cross beam and framework of wood or
iron with a hole in the cross beam made for the purpose of admitting an
insulated guide rod, also by preference of iron, on the end of which is fixed an
iron circular plate with holes therein of a diameter such that four or more
go to the square superficial inch; this circular plate fits easy, but as exactly as
possible into the cylinder aforesaid. To this plate is also attached sweeps,
blades, or rods of iron which depend from it at convenient distances downwards
so that when the guide rod, which is made strong enough is made to rotate
either by hand or machinery, the metal in the pans or cylinders is stirred and
the silver alloys and other impurities are allowed to ascend, which being of
lighter specific gravity than lead, separate themselves from the lead and rise
to its surface, and this is effected by the application of suitable menstruums,
and by exciting their molecules by electric currents however generated, with
or without the use of tension coils made to pass through the lead. In addition
to the pierced plate above mentioned I employ another circular plate not
pierced, arranged to slide up and down the guide rod, in order to close at
pleasure the holes in the pierced plate.
The following is one example of my mode of operating :-Having ascertained
the capacity of the pans or purifying cylinders I dissolve, by preference, in
the proportions of two parts more or less muriate of soda, with one part more
or less of muriate of ammonia in water, and combine this solution with dry
sawdust or other carbonaceous matters; when this compound is dry or nearly
so, I place the mixture at the bottom of the purifying pans underneath the
plate attached to the guide rod aforesaid, or I mix them. dry with sawdust, or
other carbonaceous matters, and first raising the moveable circular plate,
turn the stop-cock of the melting pan or cylinder into it, and on sufficient
metal being admitted into the pan, the aforesaid plate is then lowered, I keep
turning the guide rod aforesaid, either by means of an insulated handle, or by
a pair of small spur wheels placed above the aforesaid guide rod arranged so

page_text: of
as to be turned by machinery, and which may be made to slide in and out
of gear at pleasure; or instead of the foregoing process I propose to extract
and separate silver from lead, and clear it from impurities by the use of
electricity combined with the action of gases, such as chlorine or ammonia,
the chlorine or ammonia being forced into the fused lead, through a tube or
tubes placed in or near the bottom of the cylinder containing the lead from a
chamber communicating with it, capable of holding a certain amount of
chlorine or ammonia, this chamber is connected with a pipe passing through
the bottom of the pan, and when lead to the depth of an inch has been allowed
to run into the pan, the chlorine or ammonia is admitted under pressure, and
electricity being simultaneously applied to the above revolving rod and stirrer,
and to the metal pan and the lead contained in it, the silver, together with
the impurities in the lead, are separated from it. I would here remark the
blades attached to the round pierced plate of the guide rod before mentioned,
may be formed hollow and pierced with holes, and made to contain any
the above chemicals, or a hollow perforated reciprocating or horizontal rotating
piston or arms, or a rotating wheel with perforated vessels about its periphery
containing the aforesaid chemicals, working in a trough through which the
lead flows may be employed in lieu of the hollow blades, pistons, or arms
before-mentioned. Electricity being simultaneously applied by attaching an
insulated wire from one pole of a battery to the guide rod aforesaid, or other
apparatus in motion containing the chemicals and another insulated wire
from the other pole of the battery to the metal pan, containing the lead, or
to the lead itself in fusion, it is obvious that the above processes can be
applied direct to lead as it runs from ordinary lead smelting furnaces, or in
lieu of remelting pig lead, also in lieu of or in addition to the above chemicals,
I further use the compounds of chlorine, ammonia, bromine, iodine, and
sulphur, and after either dissolving them in alcohol, or other spirits, or in
water, or pounding them up with alcohol or other spirits or water, I
saturate them with sawdust or other carbonaceous matters to dryness, or
nearly so, use them in the manner above mentioned under the perforated
plate as before-mentioned, or in the hollow arms projecting therefrom, or in
hollow pistons or other vessels as before stated, the electric current being
imultaneously applied; and further 1 infuse the free gases, as, for example;
hose of chlorine and ammonia, in water, and saturate them as above with
carbonaceous matters for use as above stated in the manner described. .I
urther in some cases use a small proportion of nitre not sufficient to cause
xidation, in combination with the above chemicals for the purpose of exciting
heir action.

page_text: Amongst other modifications the following arrangement might be adopted :-
The lead may be poured into a heated vessel containing perforated tubes
placed near each other, filled with chemicals and electricity being applied, the
.lead would as it passed along in a subdivided state part with its silver and
impurities so that by having several of these vessels, the lead could be further
purified by passing through them, and while one vessel or set of vessels was
being emptied and cleaned out, and having fresh chemicals filled in, the stream
of lead could be turned into others ready prepared.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Arther Wall in the Great Seal Patent Office on the
1st May 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ARTHUR
WALL, of Canton Street, East India Road, Poplar, in the County of Middlesex,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the First day of November, in the year of our
Lord One thousand eight hundred and sixty-two, in the twenty-sixth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Arthur Wall, Her special licence that I, the said Arthur
Wall, my executors, administrators, and assigns, or such others as I,
the said Arthur Wall, my executors, administrators, and assigns, should
at any time agree with, and no others, from time to time and at all 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
"IMPROVED PROCESSES FOR PURIFYING LEAD AND EXTRACTING AND SEPARATING
SILVER THEREFROM, AND IN MACHINERY FOR THOSE PURPOSES," upon the condition
(amongst others) that I, the said Arthur Wall, my executors or administrators,
by an instrument in writing under or their, or one of their hands and
seals, should particularly 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.
,
1 Anthur all do hereby declare

page_text: the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement, that is to say:-
This Invention consists in the application of electricity or electric currents
as herein-after described to the purification of lead, and separation of silver
therefrom. Thus, for example, I take crude lead or lead containing silver or
other metals or impurities, such as arsenic, phosphorous, or other ingredients,
and melt them in a pan or iron cylindrical vessel, suitable for the purpose,
and when in a fit state of fusion, I convey it through a pipe having a stop-cock
to another cylindrical iron vessel placed at a lower level, where it undergoes
the first process of separation and purification, and from thence I convey it
through another pipe baving a stop-cock, to a third or more similar cylindrical
vessels, where the process is completed, after which the lead is allowed to run.
through out of another pipe having a stop-cock, to form ingots of purified lead,
while the silver with the scoriæ or allows are either previously skimmed off or
allowed to remain in the pans; when the latter is the case the fire is raised;
and all the lead fusible in the scoriæ or alloys is separated from them, and set
apart as silver lead. The apparatus or machinery I use for this purpose
consists of three or more cylindrical vessels made of copper, iron, or other
metal or material suitable for the purpose of melting lead. The first I use is
a melting cylinder, whose capacity may be of any convenient size, and capable
of holding more or less from a few pounds weight to one or more tons of fused
metal, the other two pans or cylinders, which are placed each in a level lower
to the other by some inches, or even feet, are considerably smaller,' and those
I use for purifying and extracting the silver from the lead. These latter have
placed over them and on each side of them, and sunk into the earth, strong
posts for the purpose of supporting a cross beam and framework of wood or
iron, with a hole in the cross beam, made for the purpose of admitting an
insulated guide rod; also by preference of iron, on the end of which is fixed
an iron circular plate, with holes therein of a diameter such that four or more
go to the square superficial inch. This circular plate fits easy, but as exactly
as possible into the cylinder aforesaid. To this plate is also attached sweeps,
blades, or rods of iron, which depend from it at convenient distances down-
wards, so that when the guide rods, which is made strong enough, is made to
rotate either by hand or machinery, the metal in the pans or cylinders is
stirred, and the silver alloys and other impurities are allowed to ascend, which
being of lighter specific gravity than lead, separate themselves from the lead,
and rise to the surface; and this is effected by the application of suitable
menstruums, and by exciting their molecules by electric currents, however

page_text: generated, with or without the use of tension coils made to pass through the
lead. In addition to the pierced plate above mentioned, I employ another
circular plate, not pierced, arranged to slide up and down the guide rod, in
order to close at pleasure the holes in the pierced plate.
The following is one example of my mode of operating-Having ascertained
the capacity of the pans or purifying cylinders, I dissolve, by preference in the
proportion of two parts, more or less, muriate of soda with one part, more or
less, of muriate of ammonia, water and combine this solution with dry sawdust
or other carbonaceous matters. When this compound is dry, or nearly so,
I place the mixture at the bottom of the purifying pans, underneath the plate
attached to the guide rod aforesaid; or I mix them dry with sawdust or
other carbonaceous matters, and first raising the moveable circular plate, turn
the stop-cock of the melting pan or cylinder into it, and on sufficient metal
being admitted into the pan, the aforesaid plate is then lowered. I keep
turning the guide rod aforesaid either by means of an insulated handle, or by
a pair of small spur wheels, placed above the aforesaid guide rod, arranged so
as to be turned by machinery, and which may be made to slide in and out of
gear at pleasure. Or instead of the foregoing process, I propose to extract
and separate silver from lead, and clear it from impurities by the use of
electricity combined with the action of gases, such as chlorine or ammonia,
being forced into the fused lead through a tube or tubes placed in or near
the bottom of the cylinder containing the lead from a chamber communicating
with it, capable of holding a certain amount of chlorine or ammonia. This
chamber is connected with a pipe passing through the bottom of the pan, and
when lead to the depth of an inch has been allowed to run into the pan, the
chlorine or ammonia is admitted under pressure, and electricity being simul-
taneously applied to the above revolving rod and stirrer, and to the metal pan,
and the lead contained in it, the silver, together with the impurities in the
lead, are separated from it. I would here remark the blades attached to the
round pierced plate of the guide rod before mentioned, may be formed hollow,
and pierced with holes, and made to contain any of the above chemicals; or a
hollow perforated or reciprocating or horizontal rotating piston or arms, or a
rotating wheel with perforated vessels about its periphery containing the
aforesaid chemicals, working in a trough through which the lead flows, may
be employed in lieu of the hollow blades, pistons, or arms before mentioned,
electricity being simultaneously applied by attaching an insulated wire from
one pole of a battery to the guide rod aforesaid or other apparatus in motion,
containing the chemicals, and another insulated wire from the other pole of
the battery to the metal pan containing the lead, or to the lead itself in fusion.

page_text: It is obvious that the above processes can be applied direct to lead as it runs
from ordinary lead smelting furnaces, or in lieu of remelting pig lead, also in
lieu of or in addition to the above chemicals, I further use the compounds of
chlorine, ammonia, bromine, iodine, and sulphur, and after either dissolving
them in alcohol or other spirits or in water, or pounding them up with alcohol
or other spirits or water, I saturate them with sawdust or other carbonaceous
matters to dryness, or nearly so, use them in the manner above mentioned
under the perforated plate, as before mentioned, or in the hollow arms
projecting therefrom, or in hollow pistons or other vessels, as before stated, the
electric current being simultaneously applied. And furthur I infuse the free
gases, as for example, those of chlorine and ammonia, in water, and saturate
them as above with carbonaceous matters for use, as above stated, in the
manner described. I further in some cases use a small proportion of nitre,
not sufficient to cause oxidation, in, combination with the above chemicals, for
the purpose of exciting their action. Amongst other modifications the.
following arrangement might be adopted :-The lead may be poured into a
heated vessel containing perforated tubes, placed near each othér, filled with
chemicals, and electricity being applied, the lead would, as it passed along in
a subdivided state, part with its silver and impurities, so that by having
several of these vessels the lead could be further purified by passing through
them, and while one vessel or set of vessels was being emptied and cleaned
out, and having fresh chemicals filled in, the stream of lead could be turned
into others ready prepared.
In order to explain my said Invention as completely as possible, I now
proceed to describe the best means I am acquainted with for carrying the
same into practical effect, reference being had to the illustrative: Sheet of
Drawings accompanying these Presents, and to the numeral figures and
letters of reference marked thereon respectively as follows:-
e
DESCRIPTION OF THE DRAWING.
Figure 1 shews a section of the machinery above referred to; Figure 2 is a
top plan of the upper cylindrical pan or vessel; Figure 3 a top plan of the
pan or vessel for applying various chemicals to the purification of lead, separa-
ting the silver therefrom; Figure 4 is a section of a pan with blades or beaters,
and Figure 5 details herein-after described; Figure 6 is a top plan view of
another form of pan; Figure 7, a transverse, a vertical section of same thro'
the line A, B, at Figure 6. At each of the foregoing Figurés similar letters
of reference are employed to denote corresponding parts in the Drawing.

page_text: At Figure 1, A represents the melting and purifying pan or cylinder of iron,
copper, or other metal. It is placed over a furnace or surrounded by flues
in the ordinary manner, crude lead or lead containing silver or other metals
or impurities, such as arsenic, phosphorous, or other ingredients, is placed in the
pan, and when in a state of fusion it is conveyed through the tube B at the
bottom of the pan or vessel A, furnished with a plug or stop-cock C to another
pan or cylindrical vessel D, placed on a lower level, and termed the refining
and.desilvering pan containing tubes D¹, pierced with holes, and in which the
electrolyte or chemical menstruum is placed; E, the cover, bolted to the pan.
In this vessel, D, the lead thus purified passes through the tube B to one or
more similar vessels F, also furnished with a tube B, and screw plug C, and
from the latter vessel the lead runs to be formed into ingots. Each of these
pans is fitted with a trough G, in which is placed a fire (as shewn at Figure 5)
to keep the lead melted as it passes through the tubes B, B, the hole H in
the tubes B, B, may be closed by the screw plug C when necessary; in the
upper or melting and purifying pan are placed the metallic beaters I, I, a
suitable number of these are fixed by rivetting or otherwise to the iron
arms J, J, placed at right angles to each other, and attached to a ring K; a
series of these beaters are fixed to the vertical shaft spindle L which works in
a socket M at the bottom of the cylinder A, the upper part is formed with a
square socket N, in which is placed the square end of the vertical rod O and is
made tight by the set screw P; this rod passes through the cross guide Q,
bolted to the wall or other support R, and its upper end enters and revolves
in a guide rod S, bolted by the flange T, to the support R. The latter rod also
passes through a cross guide U, and is insulated by gutta percha or other
suitable material where required, when electricity is employed motion is given
to the beaters I, I, by the shaft, and driving pulley V. The construction of
the pan exhibited at Figures 6 and 7, is as follows:-A¹ is a casting formed
with flanges B' and C¹, the flange B' rests on the brickwork setting of the
furnace, and the flange C¹ serves to form the top of the flues surrounding the
pan; D¹ is a jacket formed of pieces of cast-iron lined at a¹ with fire-brick ;
E, a plug for drawing off the molten metal; G', a furnace; H¹ is a damper.
DESCRIPTION OF THE PROCESSES.
I take pig lead, usually called "brut," or lead with alloys of several metals
mixed, and melt them in a pan made of iron or other suitable metal, or of
earthernware, and as soon as the metal is fused or melted I place in said pan
a menstruum of acids, or their bases, or both together, mixed up with carbonaceous

page_text: matter in the proportions hereafter stated to take up any superfluity of
moisture they may contain. This mixture of carbonaceous matter with its
acid or base, or both, I term a menstruum or electrolyte, and I employ-it
for purifying lead either with or without the aid of a voltaic pile or battery in
the process of purifying and desilvering lead as hereafter described. The.
process of purifying I effect by the aid of excitants placed in the pan (which
said pan for desilvering or purifying lead must be of a peculiar make and set)
hereafter described. Being now fitted with the heterogeneous mixture of
metals, and semi-metals contained in unpurified pig lead, these metals are.
made to act on each other at high temperatures, and having their molecules
excited, and also their different electricities by the menstruums or electrolotes-
I use, become separated from the lead and from each other, and according to
the order and laws of their several electricities they will tend to the poles, that
is to say, the semi-metals will get oxidized at the oxygen pole and ascend to
the surface whilst the negative metals silver, gold, copper, and iron, will
pass to the bottom of the pan where they may be removed with a portion of
lead. By the above means and allowing the metal to cool down all the silver,
gold, and copper will be found at the bottom of the pan; whilst this electrical
action. is going on in the pan by the several metals and the menstruum before-
mentioned, it will be desirable to stimulate or excite and direct the static and
irregular electricities by a current or currents of electricity from a voltaic
pile or battery of any or either of those known or in use, this facilitates the
operation and clears the lead quickly of its alloys and makes the several metals
arrange themselves at the poles with greater precision. Having charged the
vessel A, Figure 1, with lead, and placed the guide rod O, stirrer I, and
drum a, as low in the lead as I consider proper, and the electricity in its
place and imparted motion to the stirrer, I raise the heat until the whole
molten mass becomes a clear bright red color, I keep it at this heat, still
stirring the mass whilst the metal boils or simmers from the evolution of gases
or the agency, or power of electricity or both. When the evolution of gas
or gases, and the ebullition of the metal ceases, I skim off the oxides that
have gathered on the surface of the molten metal and place them aside,
I now change my battery poles making the pan that was previously the
hydrogen pole the oxygen pole, and vice versâ, I still keep up the fire some three
or four hours longer and replacing fresh menstruums in the pan; this process
I repeat twice or thrice, after which the stirrer I is withdrawn from the pan
or pans (and another bar or rod of iron without stirrers put in its place) to
conduct the electricity to any part of the pan I think proper to direct it
and as soon as the scoriæ and oxides are cleared from. the surface the poles

page_text: of the battery are again. reversed; I prefer using a pan of the construction
exhibited at. Figures 6 and 7, in which case I proceed to throw back the
jacket D thereof, and the damper H¹ in the flue that allowed the heat or
flame to circulate previously around; the upper part of the pan is now shut off;
another damper, fitted to flues leading in a different direction, which was shut
whilst the metal was undergoing the process is now, opened, and the heat from
a small fire sufficient to keep the metal in the bottom or boot of the pan from
consolidating is allowed to pass under and around this part of the pan; the
metal at the surface soon consolidates from the sides to the centre, and as
soon as this consolidation approaches the rod to which the electricity is
attached or not attached, as the case may be, the lead for about three or four
inches around the rod should be removed, and the lead so removed be thrown
to the sides of the pan; when this alternate consolidation and removal
round the rod progresses as low down as to reach the end of the rod,
or as far as the operator chooses, or near the top of the instep of the boot
part of the pan, the metal below should be drawn off by a tap or plug fixed in
the toe of the boot; the products will be found to be silver lead; there must be
a stirrer and replacing rod to each pan, and the pans may be worked either
separately or in order of succession; but I prefer working them in succession,
as by doing so more silver can be concentrated and less lead sent to the cupel;
as soon as all the fluid metal in the boot or pan is drawn off the jacket is
replaced and the damper to the pan withdrawn, the fire raised as quick as
possible, and the same process repeated until all the silver in the lead is
extracted, which will be done in two or more processes, or heatings and
coolings. In cases where there is no outlet .at the bottom of the pan for
running off the silver, and merely for purifying the lead from its alloys, the
electrolytes or menstruums, above mentioned, are: used, but in greater quantity,
as hereafter described, in order to oxidize the metals or semi-metals that
may be mixed with the lead as much as possible, or to act upon it so as to
break their affinities for lead, which, when effected, causes them to rise to the
top of the pan mixed with the menstruum or electrolyte in the state of oxides;
these are removed by skimming, whilst on the stirrer and replacing rod will
be found, if electricity be used, copper, lead, zinc, and iron, or if not there,
on the sides of the pan itself, according as the poles of the battery are placed.
In the latter process I prefer making the pan, the oxygen pole, and the
stirrer, and replacing rod the hydrogen pole of the battery alternately, and
after removing the scoriæ, or exhausted menstruum, or electrolyte by skim-
ming, I take off the melted metal to the depth of two or more inches, either
by means of a shallow ladle or by means of a tube and tap placed some inches

page_text: below the level of the lead in the pan; this process is also applicable to the
purification and desilvering of lead as it is being melted and run from a blast
furnace. The semi-metals, such as zinc, antimony, arsenic, sulphur, phos-
phorous and other semi-metals are effectually driven off and evolved as gaseous
compounds or become oxidized, and to effect these purposes I use the same
means when desilvering when lead is the object as for those processes already
described, excepting that the receptacle for the lead and the pans are larger.
To purify lead from its numerous debasing alloys the rods destined for the
poles of the battery (if a slagging furnace be used), I place in the sole or
hearth of the furnace at the extreme ends of the dish or bed where the fluid
metals rest, and when sufficient metal is collected or before, then, as the case
may be, the wires attached to the poles of a powerful battery are attached to
these two rods when the currents of electricity passing between the two points
will be found to evolve the above metals at the oxygen pole, whilst the pure
or real metals will be found to settle on and around the hydrogen pole. In
the blast furnace, where the purification may be more efficiently performed,
the poles are differently placed, as follows:-I employ two rods so arranged
that one rod enters the sole or hearth of the furnace, so as to allow an inch
or two only of said rod to appear above its surface; this rod should be sur
rounded by some efficient non-conducting substance (so as to prevent contact
with the earth) throughout its entire length, except that part where it enters
the hearth or sole of the furnace, the other rod or pole may be made to touch
the inside of the furnace under or about the tuyeres, or it may be a strong
cast-iron plate suspended by a chain from a cross beam placed above, and
this plate may be allowed to rest upon the slag as thrown into the furnace,
but care must be taken not to exclude it from the external air; this being
done, and the furnace in blast the wires from a battery are attached to the
pole rods aforesaid, and kept so as long as the furnace is in work or in blast.
It is advisable, but it is optional with the operator or director of the battery,
to attach the wire from either pole of the battery to the rod in the hearth,
whilst the other wire may be placed any where, either as herein stated or any
where about the circle of the tuyeres.
'
I now proceed to describe the proportions of the ingredients I have found
answer well in practice for conducting my processes. The menstruums or
electrolytes I prefer using may be prepared as follows:-To one part of
muriate or nitrate of ammonia, either separately or combined, I add two or
more parts of chloride of sodium or muriate of soda; I intimately mix these
by pounding or grinding them together, and I either use them in this state or

page_text: dissolve them in water, noting the weight of the salifiable bases or bases in
solution; after careful evaporation of the superfluous water at a low heat I
either pass into it chlorine gas in combination with oxygen gas, by which
means it becomes an oxychlorate, or I add to the solution instead the same
number of pounds of chloride of hydrogen (muriatic acid), oxychloric, sul-
phuric, bromic, or any of the compounds of these acids; after carefully mixing
them singly, or in combination, I saturate to dryness or nearly so, with finely
pulverized rosin, pitch, tar, sawdust, powdered charcoal, pit coal, or coke in
fine powder, separately or together, in about equal quantities, this I place in a
wooden box or chest with a false bottom in which holes are pierced for the
purpose of percolation; the liquor that runs off is again saturated with the
same like carbonaceous matters and is ready for use. The carbonaceous
matter should also be carefully weighed before saturation, so that the weight
of the menstruum before being put into the hot lead will give the amount of
salifiable bases in the mass about 24 to 30 pounds, more or less, of this men-
struum with a current of electricity from a series of pairs of a voltaic pile or
battery of about 2,000 superficial inches, more or less, desilvers and purifies
from 5 to 10 tons of lead from its alloys of semi-metals in a short time; or,
instead of the above, I saturate the acids, with the carbonaceous matters above
mentioned, either separately or in combination, and place them under the
salifiable base in the melting pan. In this case I use sulpho-cyanogen and
cyanides, and sulphuric or hyposulphurous acids; I use with these either a
nitrate or bichlorate of potass in small quantities or nitrate of potassium;
when I use salifiable bases in their normal state, as before mentioned, when
using gases, such as chlorine, oxygen, nitrogen, or hydrogen I press them into
the hot metal through a hole or holes made in the drum a, at Figure 1, of
about one-fourth of an inch or more in diameter for the insertion of a pipe,
through which oxychloric or ammoniacal gas may be made to pass into the
salifiable base under the drum a of the guide rod now in its place in the hot
metal. In such cases I prefer evolving and forcing them into the salifiable
base (oxygen), by which means the chlorine evolved from the bases takes
up a large amount of oxygen, and thus becomes by a new process intensified
oxychlorine gas; I generate the aforesaid gases by any of the known means,
and force them into the molten metal either by a force pump or other suitable
means.
66
Having now fully described the nature and object of my said Invention,
Improved Processes for Purifying Lead, and Extracting and Separating
Silver therefrom, and in Machinery for those Purposes," together with the

page_text: best means I am acquainted with for carrying the same into practical effect,
I hereby declare my Invention to consist in and I claim the
processes above
described and set forth for purifying lead, and extracting and separating there-
from the silver contained therein by the use of chemicals and carbonaceous
matters, either separately or in combination with electricity however generated,
and the machinery herein described and represented for those purposes.
In witness whereof, I, the said Arthur Wall, have hereunto set my
hand and seal, this First day of May, in the year of our Lord One
thousand eight hundred and sixty-three.
ARTHUR WALL. (L.S.)