IMPROVEMENTS IN SMELTING COPPER, GOLD, AND OTHER ORES
Year: 1861

page_text: LETTERS PATENT to Hugh Macmeikan, of Stratford, in the County of
Essex, for the Invention of "IMPROVEMENTS IN SMELTING COPPER, GOLD, AND
OTHER ORES." A communication from abroad by Rowland Vounder
Rodda, of Alberton, near Adelaide, South Australia.
Sealed 4th April 1862, and dated the 18th October 1861.
PROVISIONAL SPECIFICATION left by the said Hugh Macmeikan at the
Office of the Commissioners of Patents, with his Petition, on the 18th
October, 1861.
I, HUGH MACMEIKAN, of Stratford, in the County of Essex, do hereby
declare the nature of the Invention for "IMPROVEMENTS IN SMELTING COPPER
GOLD; AND OTHER ORES," to be as follows:-
This Invention has for its object improvements in smelting copper, gold,
and other ores. For this purpose the ore, either in a raw state or previously
roasted, is mixed with charcoal or carbonaceous material, with which it is
heated to reduce the metal contained in the ore to a metallic state (unless, as
is the case with gold ore, it is in this state already); afterwards the heat is
raised until it becomes sufficient to melt the metal, but not the earthy matters
with which it is associated. Whilst the heat is thus maintained the particles
of metal agglomerate and form globules, and when this has taken place to
a sufficient extent, the ore is removed from the furnace and the metal sepa-
rated by washing.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Hugh Macmeikan in the Great Seal Patent Office on the.
17th April 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HUGH
MACMEIKAN, of Stratford, in the County of Essex, send greeting.
.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighteenth day of October, in the year of our Lord
One thousand eight hundred and sixty-one, in the twenty-fifth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Hugh Macmeikan, Her special licence that I, the said Hugh Macmeikan,
my executors, administrators, and assigns, or such others as I, the said Hugh
Macineikan, 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 "IMPROVEMENTS IN SMELTING COPPER,
GOLD, AND OTHER ORES," a communication to me from abroad by Rowland
Vounder Rodda, of Alberton, near Adelaide, South Australia, upon the con-
dition (amongst others) that I, the said Hugh Macmeikan, my executors or
administrators, by an instrument in writing under my, 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.
NOW KNOW YE, that I, the said Hugh Macmeikan, do hereby declare
the nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-:
The ores to be operated upon are, if necessary, first freed from sulphur,
arsenic, antimony, or other substance of a like kind by calcination. The
ores, then broken to a convenient size, an inch gauge would in most cases
be suitable, are mixed with about an equal bulk of charcoal or other car-
bonaceous substance, and are subjected to moderate heat in a close vessel.
In the arrangement of furnace herein-after described, the heat, which in
ordinary smelting processes is wasted up the chimneystack, is economised, and
suffices for the above purpose. The heated charcoal or other substance having
a strong affinity for oxygen acts upon the oxides or carbonates or other ores
having oxygen or carbonicacid intheircomposition, and by expellingor partially
expelling these gases from the ores in which they are combined, metallizes or
partially metallizes the ores. The metallized or partially metallized ores still
mixed with the charcoal, as previously described, are then passed into a second
receptacle,and subjected to a higher degree of heat, such as that of an ordinary
reverberatory furnace. Here the heat has to be so regulated as to cause the
fusion of the metal within the gangue or stony portion of the ore without the

page_text: fusion of the gangue or stony portion itself; hence the formation of slag is
avoided. By the influence of molecular attraction the fused metal runs
together within the pores or substance of the stone or gangue, and is found
imbedded within the same. A sufficient degree of heat to accomplish this
having been obtained, the charge is withdrawn and thrown into water to
separate the unexpended portion of the charcoal by floatation. The ores
are then crushed to powder by hand or suitable machinery, and the granulated
metal separated by washing. Though, in the foregoing description, and in a
description of my furnace which follows, I have assumed the employment of
carbonaceous substances to be mixed with the ore, this is not necessary.
Another method is, by forcing a stream of hydrogen or other gas having
an affinity for oxygen through the heated ore, and this gas may either be
generated within the vessel containing the ore, or made at a distance
therefrom, and passed into the vessel containing the ore by aid of pipes or
gasometers or other convenient apparatus.
In carrying out the above-described process, I claim no particularly construc-
ted furnace, but the one of which the following is a description is preferred for
working on a large scale where carbonaceous substances are to be used.
A furnace with three soles or bottoms, one over the other.-The heat is made
to pass under the second or middle sole, and over the roof of the second and
under the first sole. The raw ores with charcoal or other fuel containing a
large portion of carbon are first placed on the first sole, which may be either
closed at the top, leaving only holes in different places, or left quite open. The
heat from the flues passing under this sole (which may be made of iron tiles or
other suitable substances) deprives the ore of its water and very volatile gases;
they are then let down through the roof into the middle furnace, which is
hotter than the first; this chamber or furnace has no flues running through it,
but under it, over it, and by the sides, having one or more openings near a
door or doors at one end for the escape of the gases. In this chamber or
furnace the metallization of the ores is nearly completed. The contents are
then raked through holes in the roof of the third sole, which, having had the
whole heat passing through it, is hot enough to fuse the metal, but not to fuse
any stony matter associated with the ores. This third sole may be formed into
three distinct furnaces running the whole length from the bridge to the
opposite end. As soon as the heat is raised to a sufficient intensity, the ash-
pit and fire-doors are closed and all atmospheric air is kept from entering..
Previous to closing the fire-door, a few shovelfuls of charcoal or anthracite
coals may be thrown on the fire. A gas arises from those substances after all
hydrogen and sulphur have been allowed to escape, which I call the gas of

page_text: carbon, because it has no oxygen in its combination, as is the case with
carbonic acid gas. This gas of carbon assists the operation and prevents
the ores from oxidization. Sufficient heat may be kept in a furnace by the
means I have described for several hours to melt copper without adding
one particle of fuel.
While the ores are undergoing the last part of the process in the bottom
sole, a second charge is being operated upon in the middle, and another in the
upper sole, so that three different charges of ores are undergoing certain parts
of the process at the same moment and by the heat from the same fire-place.
When it is found that the charge in the lower furnace is sufficiently operated
upon it is drawn through holes at each doorway connected with cubs or vaults
underneath the furnace, and when sufficiently cool, taken to the washing place
deprived of the charcoal, and then crushed and washed. The charcoal which
by each operation loses about twenty per cent. only in weight may be used
again when dry. When ores of very rich quality, say from twenty-five per
cent. and upwards, are to be subjected to my process, I use a furnace which
has a sole made similar to common reverberating flowing furnaces with a well,
either at one end or at the side for either lading or tapping the metal out of
the furnace. When rich ores are operated on by my plans a large portion of
the metal percolates through the hollows formed by the lumps of ore and
charcoal, and falls to the bottom of the furnace. The other portion is raked
off in the usual way. The charcoal ought to be about the same size as the
The great object in metallizing is to keep each lump of ore separate by
means of some carbonaceous fuel, so that the volatile gases from the ores may
the more easily escape, and the gas of carbon take the place of those gases and
mix with any remaining portions of oxygen forming carbonic oxide. Ores
which contain sulphur, arsenic, antimony, or bismuth are first roasted in a
furnace of a peculiar construction; this furnace may be made of any length,
breadth, or height, and consists of three permanent walls made of bricks, stone
or clay, with air holes passing through these walls, having sliding dampers or
any other contrivance connected with those holes for the regulating the
admission of atmospheric air. There are also gratings of iron, or tiles, or
bricks, in the bottom of this furnace connected with draught holes on each side
at the bottom or surface of the ground. The front part of this furnace may
have a temporary and moveable front of iron, with holes perforated in it; or
when the furnace is charged, it may be built up of loose bricks, or with bricks
and mortar, leaving openings in various places; this furnace may be connected
with flues for collecting and condensing the sulphurous vapors. The ores are
placed with wood or any other fuel in alternate layers, and when the furnace
ore.

page_text: is charged it is to be lighted from underneath. Care is to be taken that too
much air is not admitted at the commencement of the process. The width
of such a furnace must be very small, compared with its length, because the
object is to submit as much of the ore as possible to the action of the atmo-
spheric air while red hot. One thousand tons of ore can be as easily
roasted by this process as one, if proper care be taken. The whole of the
sulphur will not be expelled by this method. The ores are afterwards
re-calcined in a common calcining furnace.
By my process the chlorides, which under ordinary processes of smelting
are evaporated and escape into the atmosphere, are saved. The means by
which I collect such metallic vapors are as follows:-I cause the said
metallic vapours either to pass through pipes or flues leading from the
furnace into water, or through a flue, chamber, or chimney filled with
coarsely ground charcoal, coke, or other substance, on which the chlorides or
vapours of metals may be precipitated, and by throwing a stream of water
from the top of such flue, chamber, or chimney, I dissolve such chlorides,
the metal from such solutions being precipitated by the usual means.
Having thus explained the nature of the Invention, and the manner in
which it is to be performed, I would state that the Invention is not confined
to the precise method herein described;. but what I claim as the Invention is
the reduction of ores by fusion of the metallic portions within the substance
of the gangue or stony portion of the ores, and without the fusion of the
gangue or stony portions themselves, together with the subsequent separation
of the metallic and stony portions by crushing and washing; the carbonaceous
material employed may consist of gases having an affinity for oxygen to
serve the purpose of metallizing the metallic portions of the ores within
their gangue on bringing such gases or other substances and the ores into
contact within closed and heated vessels.
In witness whereof, I, the said Hugh Macmeikan, have hereunto set my
hand and seal, this Sixteenth day of April, in the year of our Lord
One thousand eight hundred and sixty-two.
HUGH MACMEIKAN. (L.S.)