CERTAIN IMPROVEMENTS IN THE MANUFACTURE OF METALS FROM THEIR ORES
Year: 1847

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSEPII
CLINTON ROBERTSON, of 166, Fleet Street, in the City of London, Civil
Engineer, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Ninth day of September,
One thousand eight hundred and forty-seven, in the eleventh year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Joseph Clinton Robertson, my exors, admors, and assigns, Her especial licence,
full power, sole privilege and authority, that I, the said Joseph Clinton
Robertson, my exors, admors, and assigns, or such others as I, the said
Joseph Clinton Robertson, my exors, adñiors, or assigns, should at any time
agree with, and no others, from time to time and at all times during the term
of years therein expressed, should and lawfully might make, use, exercise, and
vend, within England, Wales, and the Town of Berwick-upon-Tweed, and in
the Islands of Jersey, Guernsey, Alderney, Sark, and Man, and also in all Her
said Majesty's Colonies and Plantations abroad, the Invention of "CERTAIN
IMPROVEMENTS IN THE MANUFACTURE OF METALS FROM THEIR ORES," being a com-
munication from abroad; in which said Letters Patent is contained a proviso,
that I, the said Joseph Clinton Robertson, shall cause a particular description
of the nature of the said Invention, and in what manner the same is to be
performed, by an instrument in writing, under my hand and seal, to be inrolled
in Her said Majesty's High Court of Chancery within six calendar months

page_text: next and immediately after the date of the said in part recited Letters Patent,
as in and by the same, reference being thereunto had, will more fully and at
large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Joseph Clinton Robertson, hereby declare that the nature of the said Inven-
tion, and in what manner the same is to be performed, are fully described
and ascertained in and by the following description thereof, that is to say:-
Whereas it is well known that the ores of iron, lead, zinc, copper, tin,
silver, antimony, bismuth, cobalt, and of most other metals exist naturally as
ores in a state of combination with more or less of sulphur, phosphorous,
arsenic, and other volatilizable matters, from which it is important that they
should be freed before being subjected to the smelting or reducing process.
For this purpose they are usually roasted in heaps in the open air or on the
hearth of a reverberatory or other furnace, with exposure to the atmosphere,
it being requisite, in order to the volatilization of the matters which it is sought
to get rid of, that the air should have access to the burning mass; but this
roasting process is always tedious, and often so defective that the ore being
but very partially freed from the sulphur, phosphorous, and other volatilizable
matters aforesaid, yields, when smelted, only a crude metal, possessed of
neither the due malleability nor the proper lustre.
Now, the Invention communicated to me as aforesaid consists in the sub-
jection of the said ores to the joint action of heat and electricity in manner
following: I have ascertained that when sulphurets, phosphurets, and
arseniurets are under the influence of a high temperature, and have currents
of electricity then transmitted through them, the sulphur, phosphorous, and
arsenic being naturally electro-negative, are therefore powerfully attracted to
the electro-positive pole of a voltaic battery, and have also their usual chemical
affinities for metallic bases thereby impaired or subverted so as to yield more
readily to the volatilizing influence of the heat and pass off in a state of fumes
or vapour. The mode of carrying this Invention into practical operation may
be varied according to local circumstances, but the following description and
directions will enable any practical metallurgist to execute and apply it readily
on any working scale.
A furnace or kiln may be employed of the form and construction of the
ordinary lime kiln, and with a surmounting dome. It is made somewhat of a pear
conical, or egg shape, and lined with well-burnt bricks, made of fire-clay, and
as free as may be from ferruginous matter, or with semi-vitrified bricks, mad
by a due admixture of lime with clay and silica, in order that the lining ma
consist of materials which are to a great degree non-conductors of voltai

page_text: electricity, or at least bad conductors thereof. The grate bars may rest loosely
on cross bearings of iron, so that they may be easily shifted or replaced as
required. There may be an iron or fire-tile door at one side, a little above the
level of the grate, for withdrawing the calcined ores., From the top or side
of the dome a wide chimney proceeds, through which the vapours arising from
the furnace either pass off into the open air or into some approved condensing
apparatus.
The mode of operating with the furnace is as follows:-The grate bars are
first covered with a layer of fuel (preferring good coke or anthracite, when it
can be procured, to bituminous raw coal), over which a layer of the ore
(previously broken into small pieces, and sorted as usual) is laid; a second
layer of fuel is then laid above the layer of ore, and over that second layer of
fuel a second layer of ore, and so the operation of filling proceeds, the ore and
fuel being piled up in alternate layers till the cavity of the furnace is filled.
On the middle of the topmost layer an iron ring or cross should be laid. The
undermost layer of fuel being kindled it sets fire progressively to all the super-
jacent layers, and the roasting process begins. As soon as any considerable
portion of the mass has become moderately ignited a communication is to be
established between the iron ring or cross and a voltaic battery or other
equivalent electrical apparatus, by attaching to either of them a wire carried
from the negative or positive pole of the said battery, while from the iron
bearer of the grate bars a wire is carried to the opposite pole of the battery,
so as to establish the electrical circle and current through the mass of calcining
materials. The electrical power should be proportional to the mass of mate-
rials operated on, and the action kept up until it is seen that the sulphurets, or
phosphurets, or arseniurets, as the case may be, have been discharged, as
evinced by the ceasing of the fumes. The battery should be one of the
sustaining kind, or such that the current of electricity thus established through
the mass should be steadily and well kept up. From the ring or cross of iron
on the surface of the roasting materials, one, two, or more iron rods may be
carried downwards, either vertically or obliquely, into the contents of the kiln,
through a greater or less extent for favoring the conveyance and distribution
of the electricity.
The degree of strength with which the electric current acts will be evidenced
5 from the escape from the top of the furnace, in more or less abundance in the
form of fumes, of the sulphurous or other matters desired to be got rid of.
The activity and power of the electrical current should be tested from time to
time by transmitting it through a little acid and water in the test glass tube

page_text: apparatus well known to electricians, and described in most of the modern
treatises on voltaic electricity.
The lowest and best calcined portions of the mass are to be drawn off from
time to time, either by the side doors of the furnace or from the grate itself, by
removing two or three of the moveable bars, after the manner commonly
adopted in the draw lime kiln.
In proportion as the furnace is emptied at bottom it must be replenished
from the top with alternate layers of fuel and ore as aforesaid, in order to
maintain the mass always at the same level as nearly as may be, on which
occasions the iron ring or cross may be removed during the time of feeding,
and immediately afterwards replaced. The voltaic circuit should be also
meanwhile interrupted.
The ore after it has gone through this roasting and electrizing process is
then to be washed and reduced, either in retorts by concentration, or in a blast
furnace according to the modes in ordinary use.
And having now described the nature of the said Invention, and in what
manner the same is to be performed, I declare that what I claim is the
subjecting of the ores of metals containing sulphur, phosphorous, arsenic, and
other volatilizable matters, previous to the smelting or reducing of the same, to
the joint action of heat and electricity, as before described.
In witness whereof, I, the said Joseph Clinton Robertson, have hereunto
set my hand and seal, this Ninth day of March, in the year of our
Lord One thousand eight hundred and forty-eight.