IMPROVEMENTS IN THE MANUFACTURE OF ZINC OXIDE
Year: 1862

page_text: LETTERS PATENT to George Darlington, of Minera, in the County of
Denbigh, Zinc Smelter, for the Invention of "IMPROVEMENTS IN THE
MANUFACTURE OF ZINC OXIDE."
Sealed the 17th April 1863, and dated the 29th October 1862.
PROVISIONAL SPECIFICATION left by the said George Darlington at
the Office of the Commissioners of Patents, with his Petition, on the
29th October 1862.
I, GEORGE DARLINGTON, of Minera, in the County of Denbigb, Zinc
Smelter, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN THE MANUFACTURE OF ZINC OXIDE," to be as follows:-
My Invention consists in mixing zinc ores, with or without flux, with any
description of smokeless carbonaceous material, for the purpose of reducing
such ores, especially with anthracite coal; and I expose the said mixture to
the action of heat resulting from the combustion of a further quantity of such
smokeless fuel, especially anthracite, by placing it either in a "blast" furnace,
or in any furnace with a bar or perforated plate grate, the ash-pit to which
is closed, and which forms the air chamber for the reception of air furnished
for the combustion of the contents of my furnace, either by a fan or other
blast apparatus. It should be distinctly understood that my furnace is to be
" open" furnace, and that the contents of the said furnace, that is to say,
the zinc ore mixed with a proper proportion of smokeless fuel, is either mixed
with the smokeless fuel which beats the furnace, or the said mixture of zinc

page_text: ore and smokeless fuel lies in a separate chamber, which is heated by smokeless
fuel, anthracite being preferred, and through which the products of the com-
bustion of the heating fuel pass, such furnace having the air necessary to the
combustion of the fuel supplied by the closed ash-pit arrangement before
mentioned. And I collect the oxide of zinc which will be produced by the
process herein-before described.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Darlington in the Great Seal Patent Office on the
18th April 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
DARLINGTON, of Minera, in the County of Denbigh, Zinc Smelter, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of October, 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 George Darlington, Her special licence that I, the said George
Darlington, my executors, administrators, and assigns, or such others as I, the
said George Darlington, my executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times there-
after 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 "IMPROVE-
MENTS IN THE MANUFACTURE OF ZINC OXIDE," upon the condition (amongst
others) that I, the said George Darlington, 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 Inven-
tion, 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 George Darlington, do hereby declare
the nature of my 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, reference being had to the accompanying Drawings, and to the
letters and figures marked thereon, that is to say:-
My improvements consist in the production of zinc oxide by the use of a

page_text: smokeless carbonaceous fuel acting upon a zinc ore in an open furnace, so as
to form oxide of zinc, which passing out of the furnace is conducted to the
collecting apparatus, where it is deposited. A coarsely ground mixture of the
ores of carbonate or silicate of zinc (with or without flux) and anthracite coal,
or other smokeless fuel, is placed in a furnace opening into passages leading to a
collecting apparatus, and subjected to heat produced by the combustion of similar
smokeless coal or fuel. The mixture may be placed in a separate chamber of
a furnace, and adequate heat derived from anthracite or other smokeless fuel
made to pervade the entire mass; or it may be mixed with such heating
material, and in either case the zinc oxide is extracted or separated from the
ore and deposited in the collecting apparatus.
In order to show more clearly the nature of my said improvements, and
the manner in which they may be performed, I will describe furnaces and
apparatus which may be used in carrying my Invention into effect.
The annexed Sheet of Drawings represents in Figure 1 a longitudinal
section of a furnace, in which the whole of the fuel used for the purpose of
producing heat comes into immediate contact with the mixture of zinc ore and
smokeless carbonaceous material, from which it is proposed to extract the
zinc oxide.
Upon a grate A, consisting of perforated fire-bars, and which occupies the
entire area of the chamber in which it is placed, is deposited an uniform layer of
anthracite coal, or other smokeless fuel, and then ignited. When this fuel has
been made thorougly incandescent, a coarsely ground mixture of anthracite coal.
or other smokeless carbonaceous matter, and a carbonate or silicate of zinc, in the
proportion of about one hundred of ore to forty of coal, is spread on the surface
of the aforesaid fuel, and the gases at first evolved therefrom are allowed to
escape into the air through an aperture at B. As soon as these gases assume
a green tint, which marks the commencement of the formation of oxide of
zinc, the aperture B is closed, and a passage at C (previously shut) is at the
same time opened, in order that the gases may enter the passage D, leading to
the collecting apparatus where the oxide of zinc is deposited. The ash-pit E
is closed, and the contents of the furnace are maintained at a proper degree of
heat for effecting the formation of the oxide of zinc by means of a fan or
other suitable blast apparatus communicating with the chamber F, from
whence the air passes through the opening G into the ash-pit E, E. The
contents of the furnace are from time to time broken up and stirred, to
facilitate the evolution of the fumes of zinc. When the charge ceases to give
off oxide of zinc the exhausted mass is removed, and another operation
commenced.

page_text: Figure 2 represents the longitudinal interior of a reverberatory furnace in
which the zinc.ore and the heating fuel are deposited in separate chambers.
.A broken up mixture of anthracite coal and of earthy carbonate or silicate of
zinc, in the proportion of about one hundred of ore to twenty of coal is placed
in the receptacle or reservoir H. This mixture is exposed to a proper degree of
heat, produced by anthracite coal or other smokeless fuel ignited in an ordinary
shaped fire-grate J. The combustion of the fuel is maintained and regulated
by means of a blast entering a closed ash-pit at K. The heating material is
shown, in the present instance, placed at the side of the chamber containing
the ore to be operated upon; but there are other positions in which it might
be placed. The operation then proceeds as already described in the former
illustration; the gases, together with the fumes of the zinc, passing through
the orifice C and the passage D, leading to the collecting apparatus. I prefer
to use anthracite coal in consequence of its cheapness and free action, but
any carbonaceous fuel which is smokeless, or, in other words, will not evolve
smoke during the performance of the process, so as to spoil or deteriorate the
quality of the oxide of zinc by causing it to be mixed with soot or carbon, may
be used in lieu of anthracite coal. Although I have described furnaces and
apparatus which I deem to be convenient, I do not make any separate claim
to such furnaces or apparatus.
Having thus described the nature of my Invention, and the manner in
which it may be carried into effect, I conclude by claiming the extraction of
zinc oxide from earthy carbonate of zinc (with or without flux), by heating it
in an open furnace with anthracite coal or other carbonaceous fuel, as herein-
before described.
In witness whereof, I, the said George Darlington, have hereunto set my
hand and seal, this Fourteenth day of April, in the year of our Lord
One thousand eight hundred and sixty-three.
GEORGE DARLINGTON. (L.S.)