IMPROVEMENTS IN MAKING OXIDES OF METALS, IN SEPA- RATING SILVER AND OTHER METALS PROM THEIR COMPOUNDS WITH OTHER METALS, AND IN MAKING WHITE LEAD, SUGAR OF LEAD, AND OTHER SALTS OF LEAD AND SALTS OF OTHER METALS
Year: 1842

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, the
said JonN MULLINS, of Battersea, in the County of Surrey, Surgeon, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent under the Great Seal of Great Britain, bearing date at Westminster, the
Twenty-seventh day of October, in the sixth year of Her reign, did give and
grant unto me, the said John Mullins, my executors, administrators, and assigns,
Her especial licence, full power, sole privilege and authority, that I, the said
John Mullins, my executors, administrators, and assigns, and such others as I,
the said John Mullins, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times hereafter
during the term of years therein mentioned, should and lawfully might make,
use, exercise, and vend, within England, Wales, and the Town of Berwick-upon-
Tweed, my Invention of "IMPROVEMENTS IN MAKING OXIDES OF METALS, IN SEPA-
RATING SILVER AND OTHER METALS PROM THEIR COMPOUNDS WITH OTHER METALS, AND
IN MAKING WHITE LEAD, SUGAR OF LEAD, AND OTHER SALTS OF LEAD AND SALTS OF
OTHER METALS;" in which said Letters Patent there is contained a proviso
that I, the said John Mullins, shall cause a particular description of the
nature of my said Invention, and in what manner the same is to be per-
formed, by an instrument in writing under my hand and seal, to be enrolled
in Her said Majesty's High Court of Chancery within six calendar months next
and immediately after the date of the said in part recited Letters Patent,
reference being thereunto had, will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
John Mullins, do hereby declare the nature of my said Invention to
consist,―
First, in causing oxides to form on the surface of or in melted metals
heated to the temperature of their respective points of oxydation, by forcing
gas or air, or allowing gas or air to pass through the body of the melted mass,
either by a forcing or exhausting apparatus, and then skimming off or other-
wise removing from the said surface of the said melted metals the said oxides,
whereby I am enabled, in the event of their being any admixture of metal, as
in lead for instance, which contains a portion of silver, so to surcharge the
melted mass with the foreign metal or matter as to make a subsequent
process of separation easy and valuable.
Secondly, in the manufactory of white lead, by exposing oxide of lead so
obtained as aforesaid to the vapour of vinegar and of carbonic acid gas, as
herein-after described.
Thirdly, in the manufactory of white lead, by exposing a solution of
acetate of lead, or other suitable salt of lead made from oxide of lead
obtained as aforesaid, to an atmosphere of carbonic acid gas, as herein-after
described.
Fourthly, in the use of common soot as a deoxidating agent in the reducing
of the said oxides so obtained as aforesaid, and of other metals and ores or
their oxides. And
Fifthly, in the application of magnets for separating iron from other metals,
as herein-after described.
And in further compliance with the said proviso, I, the said John Mullins,
do hereby describe the manner in which my said Invention is to be performed,
by the following statement thereof, reference being had to the Drawing
annexed, and to the figures and letters marked thereon, that is to say :-
DESCRIPTION OF DRAWING.
A, A, A, A, Figure 1, the brickwork of the furnace for heating the metal,
which in this case is supposed to be lead, in the pan B, B, with the elongated
lip C, C, the flame from the fire in the furnace grate passing along and under
the lip C, C, and carried off by the flue D. Into the pan B, B, is immersed
a tube of iron, porcelain, or other suitable material, A, Figure 2, which is in
connection with the iron vessel B. Into this vessel is condensed by means
of the pump C, air or gas, or a mixture of air and gas, the which, when
the stopcock I is opened, passes through the tube A, Figure 2, into the metal,
and rises to the surface, oxidizing the metal through which it passes; the

page_text: which oxide being of less specific gravity than the metal from which it is
formed, floats on the surface of the metal, and is continually in the course
of removal by means of the skimming plates C, C, C, C, Figure 1, which
are attached to the endless flexible chain E, E, which works round the
toothed wheels F, F; these skimming plates being kept in constant but slow
motion remove the oxide as it is made, thereby preventing the admixture of
unoxidized metal with the oxide; this is further effected by means of the
inclined plane G, G, up which it is drawn; this inclined plane is formed
of round bars which are placed a short distance apart, as shewn in the
Plan Figure 3, G, G, these bars being kept hot by reason of the body
of heated metal below them if any unoxidized metal remain in that portion
of the oxide which is removed by the skimming plates, it runs through
into the lips C, C, of the pan B, B, Figure 1. When the oxide reaches the
summit of the inclined plane, it is delivered by means of the spout H into the
receiver I. The flexible tube F, Figure 2, is for the purpose of enabling the
operator to raise or lower or otherwise shift the air tube as may seem most
convenient. G, G, safety valves. D, a mercury guage to ascertain the pres-
sure of the air or gas in the vessel B. This is necessary to enable the operator
to know when there is sufficient pressure to overcome the resistance offered
by the column of metal through which it has to pass, and to keep up a con-
stant current. The pipe H, Figure 2, is for the purpose of forming a con-
nection between the pump C, Fig. 2, with a gasometer or other reservoir of
When atmospheric
gas, when gas is employed instead of atmospheric air.
air is used this pipe may be unconnected at the union joint K.
of the pump C is marked by the vibrating stirrup rod C 1. At Figure 9 is
shewn an apparatus for the more effectual prevention of the admixture of
unoxidized metal with the oxide. The plate A, A, made of iron or other
material, is attached to the air pipe B a little above the diffuser C; when the
current of air leaves the aperture at D it strikes against this plate at E, and
passes onwards to the edge, as shewn at F. By this means any agitation
on the surface of the metal where the oxide is collected is prevented, the air
having a tendency to blow away the oxide from the place where it makes its
exit. When this plate is used the skimming apparatus must be accommo-
dated to it.
The piston
At Figure 10 is shewn another method of oxidizing metals according to my
said Invention, in which method the oxygen is generated below the surface
of the metal. Into the pan or pot A, Figure 10, is put black oxide of man-
ganese, or other material from which oxygen may be obtained, as shewn at B;
holes are drilled in the bottom of the iron pot A, for the purpose of allowing

page_text: the heated metal, supposed in this case also to be lead, to enter. The top E
is removeable, the screw at the end of the long handle C, fastening it down
when in use by passing through the cross bar D, and tightening upon the
top E, which has some fine holes drilled in it. When this is immersed in the
metal, the metal enters the pot at the bottom holes, shewn at F, and fills up
the unoccupied space. When the manganese or other material becomes
sufficiently heated, it gives off gas which will combine with the metal and
form an oxide, which, as in the former case, will rise to the surface ready for
the skimmer. The oxides thus formed, if desirable, may then be treated by
grinding, sifting, washing, or heating, to produce the various oxides of com-
merce, as the yellow pigment, massicot, red lead, and litharge, or for the
manufacture of salts of the respective metals as the operator may desire.
The metal or metals when so oxidizing as aforesaid should all be melted and
heated to the temperature of their respective points of oxidation. By the
mode of oxydation herein described, if the metal used be lead or other metal,
and should contain any silver or other metal, the latter being less oxidizable
than the former will remain unoxidized in the pan B, B, and will be con-
tinually accumulating therein; and, when the operator judges necessary, such
silver or other metal can be drawn off through the pipe M, Figure 4, by
withdrawing the valve plug N, and it will then pass away into any vessel placed
for its reception below the outlet O, to be further purified or separated. The
pipe M can be heated if necessary by the small furnace R underneath.
The oxide of lead formed by the herein-described process, attention being paid
to the heat of the metal in the pan B, B, is not vitrified or semivitrified as
is the litharge and some of the oxides of lead of commerce, and for this
reason is far more readily acted upon by chemical agents, and consequently
is preferable for the manufacture of the acetate, carbonate, nitrate, and other
salts of lead, because of its more quickly combining with the several acids;
and the same will be found of all oxides of metals made on this plan, when
treated for the manufacture of the salts of those metals.
In manufacturing white lead or ceruse I use the oxide so formed, having
first carefully washed and elutriated in the usual manner. Into chambers
made of any suitable material, as wood, lined or not with sheet lead, and of
any suitable size or shape, and having moveable air-tight lids or covers, are
placed horizontally several trays, supported one above the other, with spaces
between, which may be made of wood and lined with sheet lead, or made of
slate or other suitable material. On these trays the oxide of lead, made and
prepared in the manner herein described (the litharge and vitrified massicot of
commerce not answering), slightly moistened with distilled water, is placed

page_text: about one inch deep. These trays are introduced into the chamber, and the lid
or cover secured down; and then the vapour of vinegar, together with carbonic
acid gas, is made to enter the said chambers through suitable pipes. The vine-
gar, or the acetic acid of commerce, is put into a vessel in effect similar to the
common distilling apparatus, and heat applied in the usual way, and the vapour
thereof is directed through a pipe or pipes into the said chambers. And at the
same time, by means of another pipe, communication is made with a gas
holder or reservoir containing carbonic acid gas, made after any of the usual
methods, and the said gas is made to enter freely into the said chambers.
The room where the said chambers are placed is kept at a temperature of
about one hundred or one hundred and twenty degrees Fahrenheit. The
vapour generators and the gas holders are erected in an adjoining apartment.
When the lids or covers of the said chambers are about to be taken off, the
vapour of vinegar and the gas must be turned off by means of stopcocks
in the pipes, or by other means. By this arrangement, which is exemplified
at Figure 5, the said oxide of lead becomes in due season converted into ceruse
or white lead.
I also manufacture ceruse or white lead in a manner different to the above,
and as shewn at Figure 6, that is to say:-Into chambers or large jars of
earthenware, or other material, is suspended several large sponges or other
like substances. These sponges are supported or hung up in the jars by strings
of worsted or other like substance, or by other means, so that they do not
touch the sides of the jars, or one another. Having made a saturated, filtered,
and neutral solution of acetate of lead, or of other suitable salt of lead; from
the oxide obtained as aforesaid, and placed this vessel in a solution, above the
top of the bars, as on an adjoining shelf, and having moistened slightly the
said sponges with the solution, and also the worsted strings suspending them,
the said strings are then made to dip into the solution contained in the vessel
above the jars, and by the power of capillary action the sponges are kept con-
stantly moist by a supply of the solution descending down the worsted strings,
and the supply can be regulated at pleasure by the size of the strings and
otherwise. Evaporation is continually going on, and crops of salts of lead are
formed on the surface of the sponges. Now the jars are made to communi-
cate with a gas holder or other reservoir containing carbonic acid gas, placed
above the said jars, which gas is made to fill the said jars, and the sponges are
thus surrounded with an atmosphere of carbonic acid gas, and, by its action on
the salt of lead, converts it readily into ceruse, assisted probably by the decom-
position of the acid of the original solution. When it has been ascertained

page_text: that a sufficient quantity of the ceruse has been formed, the sponges or other
materials are removed and washed in a vessel of pure water; and if the
sponges contain any undecomposed soluble salt of lead, which is generally
the case, the water dissolves it, but the ceruse falls to the bottom on the water
remaining at rest. The water is to be re-used for forming the solution when
decanted from the precipitated ceruse; the sponges or other materials are then
replaced as before, and the process continues. The gas is easily turned into
the jars from the gas holder, through a flexible tube with stopcocks, its specific
gravity assisting its flow, and it can easily be ascertained when the jars are full
of carbonic acid gas in many ways, a ready one will be with a lighted piece of
paper or a match. The jars are slightly covered with a lid, and the worsted
strings can be made to pass through a hole on the top of the lids. The
temperature of the room where the jars are should be regulated accord-
ing to the season of the year. Instead of sponges, a frame of wood,
with cloth or other matter of like nature, strained across and suspended
vertically or otherwise, in a proper vessel, in an atmosphere of carbonic acid
gas, may be used, and supplied with the solution of the salt of lead as before,
by capillary attraction, or by a dropping apparatus, which will permit only a
certain quantity to drop on the top of the frame of cloth or other substance
as occasion may require.
In reducing the oxide of metals so obtained as aforesaid to the metallic
state, and in extracting metal from metal or (as commonly called) ore gene-
rally, I have found that the process is much facilitated, and in certain localities
much more cheaply effected, by the use of common soot, mixed up in about the
proportion of half the weight of the oxide metal or ore to be acted on at one
operation. If any oxide of metal should be found to contain iron, and it is desir-
able to remove it, I effect such removal in manner following, that is to say:-A
tray or trays of wood, or other non-conducting material, is to be formed with a
series of magnets, with their poles projecting through openings made in the
bottom of such tray to fit them. The tray may be worked by machinery, and
fixed at an angle of about thirty degrees, as shewn at Figures 7 and 8, having
a slow latteral seive-like motion; and the oxide, made as aforesaid, being sup-
plied through a hopper to the higher end, in its passage coming in contact
with the poles of the magnets, will leave any iron that may be therein contained
attached thereto.
Now whereas, it is evident, that though I have herein only described a mode
of forcing air or gasses through the mass of melted metal, yet an exhausting
apparatus that would allow the gas to rise through the metal into a vaccuum,

page_text: or partial vaccuum, would answer the same purpose. And whereas many other
modifications of apparatus or machinery may be found to effect the objects of
those parts of my said Invention which require apparatus or machinery to carry
them out, yet I have described such as will answer the purpose in the best
manner I now am acquainted with. And whereas, though I have described
my Invention, in this my Specification, principally with reference to lead, yet
other metals are susceptible of being treated on the same principle.
And I hereby claim as my said Invention,-
First, the manufacturing of oxides of lead and of other metals, by passing
currents of atmospheric air, or oxigen gas, or other suitable aeriform matter,
below the surface of or through the metal when in a melted state, at the tem-
perature of their respective points of oxidation, whereby, in the case of lead,
silver is accumulated, and rendered more easy of separation, as aforesaid.
Second, the acting on oxide of lead, so formed as aforesaid by the vapour of
vinegar and carbonic acid gas, as herein-before described, for the purpose of
manufacturing what is commonly called white lead.
Third, in the manufacture of white lead, by exposing a solution of acetate
of lead, or other suitable salt of lead made from oxide of lead, so formed as
aforesaid, to an atmosphere of carbonic acid gas, as herein-before described.
Fourth, the application of common soot to deoxidize the oxide of lead
produced as aforesaid; and generally in the reduction of metals from their
ores or oxides.
Fifth, the application of magnets to separate the iron from the oxide of lead
produced as aforesaid.
And such my Invention being, to the best of my knowledge and belief,
entirely new and never before used in that part of Her said Majesty's
United Kingdom of Great Britain and Ireland called England, Her Dominion
of Wales, nor Town of Berwick-upon-Tweed, I do hereby declare this to
be my Specification of the same, and that I do verily believe this my said
Specification doth comply, in all respects, fully and without reserve or disguise,
with the proviso in the said in part recited Letters Patent contained; where-
fore I do hereby claim to maintain exclusive right and privilege to my said
Invention.
In witness whereof, I, the said John Mullins, have hereunto set my
hand and seal, this Twenty-seventh day of April, in the year of our
Lord One thousand eight hundred and forty-three.
JOHN MULLINS. (L.S.)

page_text: AND BE IT REMEMBERED, that on the same Twenty-seventh day of
April, in the year above mentioned, the aforesaid John Mullins came before
our Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained, in form above written.
And also the Specification aforesaid was stamped according to the tenor of the
Statute in that case made and provided.
Inrolled the same Twenty-seventh day of April, in the year above
written.