IMPROVEMENTS IN THE REDUCTION AND TREATMENT OR ZINC ORES IN THE MANUFACTURE OF SPELTER, AND IN THE UTILIZATION OF THE PRODUCTS RESULTING THEREPROM, AND ALSO IN THE CON- STRUCTION OF THE FURNACES AND APPARATUS EMPLOYED FOR SUCH PURPOSES
Year: 1866

page_text: LETTERS PATENT to Charles Crockford, of Holywell, in the County of
Flint, Gentleman, for the Invention of "IMPROVEMENTS IN THE REDUCTION
AND TREATMENT OR ZINC ORES IN THE MANUFACTURE OF SPELTER, AND IN THE
UTILIZATION OF THE PRODUCTS RESULTING THEREPROM, AND ALSO IN THE CON-
STRUCTION OF THE FURNACES AND APPARATUS EMPLOYED FOR SUCH PURPOSES."
Sealed the 24th May 1867, and dated the 27th November 1866.
PROVISIONAL SPECIFICATION left by the said Charles Crockford at
the Office of the Commissioners of Patents, with his Petition, on the
27th November 1866.
I, CHARLES CROCKFORD, of Holywell, in the County of Flint, Gentleman,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
THE REDUCTION AND TREATMENT OF ZINC ORES IN THE MANUFACTURE 7 SPELTER,
AND IN THE UTILIZATION OF THE PRODUCTS RESULTING THEREFROM, AND ALSO IN THE
CONSTRUCTION OF THE FURNACES AND APPARATUS EMPLOYED FOR SUCH PURPOSES,"
to be as follows:-
The first part of my Invention consists in utilizing the sulphur contained
in the sulphuret of zine which is now wasted, and I propose to effect this in the
following manner :-
Having crushed the ore to a sufficient degree of fineness I charge it into
a close furnace or series of retorts or chambers which are heated externally,

page_text: and I keep the ore almost continually stirred by means of rakes which are kept
in motion by machinery, thus presenting fresh surfaces of the mineral to the
action of the atmospheric air, which is permitted to enter at the mouth of
the said retorts or chambers through openings by which the handles of the
rakes pass; sulphurous acid gas is thus generated which is carried off by
means of a flue at the other end of the said retorts or chambers, under
regulation by a damper, and the vapour is utilized in the following manner :----
From the fact of the sulphuret of zinc requiring a large excess of atmospheric
air for its perfect calcination the sulphurous acid gas generated by the process
of calcination is not economically available for being condensed in the leaden
chambers in which sulphuric acid is manufactured. I therefore propose to
conduct the sulphurous acid gas generated in the retorts or chambers above
described into kilns containing iron or copper pyrites, or into a chamber
containing sulphur, and the diluted gas is thus charged with the necessary
additional sulphur, and is then conducted into the ordinary sulphuric. acid
chamber, and by these means, viz., calcining the sulphuret of zinc in a close
roaster or retort, keeping the ore continually stirred and impregnating the
diluted gas with additional sulphur vapour, I am enabled to utilize the
sulphur contained in the sulphuret of zinc.
The next part of my Invention relates to the construction of furnaces for
the reduction of zinc ores. Instead of constructing zinc furnaces in the
ordinary manner by heating a chamber containing a limited number of retorts
by a single fire I place in a horizontal chamber any convenient number
of retorts in blocks or sets, with a fire placed between each block or set so
that the heat abstracted from the products of combustion in the first fire-place
is supplied or made good by the combustion of the fire in the second fire-place,
and so on, and by this means considerable economy in the consumption of
fuel is effected; moreover, by placing the fire-places in advance of instead of
immediately under the retorts the injury or destruction which occurs to the
lower row of retorts immediately over the fire is avoided, and the flame and
heat from the fuel on the grate is caused to act more uniformly.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Crockford in the Great Seal Patent Office on
the 27th May 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME I, CHARLES 3
CROCKFORD, of Holywell, in the County of Flint, Gentleman, send greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-seventh day of November, in the year of our
Lord One thousand eight hundred and sixty-six, in the thirtieth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Charles Crockford, Her special licence that I, the said Charles
Crockford, my executors, adininistrators, and assigns, or such others as I,
the said Charles Crockford, ny 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 THE REDUCTION AND TREATMENT OF ZINC ORES IN THE MANU-
FACTURE OF SPELTER, AND IN THE UTILIZATION OF THE PRODUCTS RESULTING THERE-
FROM, AND ALSO IN THE CONSTRUCTION OF THE FURNACES AND APPARATUS EMPLOYED
FOR SUCH PURPOSES," upon the condition (amongst others) that I, the said Charles
Crockford, 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 manuer 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 Charles Crockford, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement, and the accompanying Sheet of Drawings:-
The first part of my Invention consists in utilizing the sulphur contained in
the sulphuret of zinc which is now wasted, and I propose to effect this in the
following manner :-
Having crushed the ore to a sufficient degree of fineness I charge it into a
close furnace or series of retorts or chambers which are heated externally, and
I keep the ore almost coutinually stirred by means of rakes, which are kept in
motion by machinery, thus presenting fresh surfaces of the mineral to the
action of the atmospheric air, which is permitted to enter at the mouth of the
said retorts or chambers through openings by which the handles of the rakes
pass. The sulphurous acid gas thus generated the process of calcination is
not economically available for being condensed in the leaden chambers in
which sulphuric acid is manufactured; I therefore propose to conduct the
sulphurous acid gas generated in the retorts or chambers above described into
kilus containing iron or copper pyrites, or any ore containing sulphur, or into

page_text: a chamber containing sulphur; the aforesaid iron or copper pyrites or sulphur
thereby becoming ignited gives off sulphur vapour, and the diluted gas is thus
charged with the necessary additional sulphur, and is then conducted into the
ordinary leaden chamber, and converted into sulphuric acid, and by these
means, viz., calcining the sulphuret of zinc in a close roaster or retort, keeping
the ore continually stirred, and impregnating the diluted gas with additional
sulphur vapour, I am enabled to utilize the sulphur contained in the sulphuret
of zinc. Sometimes I conduct the sulphurous acid gas into a close chamber,
heated if necessary, containing sulphuret of zinc, which is kept stirred if
required, and thereby becomes partially calcined, and by parting with a portion
of its sulphur enriches the diluted gas, the completion of the calcination being
effected afterwards in the manner first described.
I do not confine myself to the close roaster as above described, as the same
process may be applied to the ordinary reverberatory furnace, in which the
sulphuret of zinc is calcined.
The next part of my Invention relates to the construction of furnaces for
the reduction of zinc ores. Instead of constructing zinc furnaces in the
ordinary manner, and heating a chamber containing a limited number of
retorts by a single fire, I place in a horizontal chamber any convenient number
of retorts in blocks or sets, with a fire-place, the bars of which are parallel
with the retorts) between each block or set, so that the heat abstracted from
the products of combustion in the first fire-place is supplied or made good by
the combustion of the fuel in the second fire-place, and so on, and by this
means considerable economy in the consumption of fuel is effected. By this
construction of furnace I am enabled to heat a double set of retorts placed
back to back, the length of the fire being parallel with the retorts instead of
transverse thereto, as in furnaces hitherto used; moreover, by placing the
fire-places in advance of instead of immediately under the retorts, the injury
or destruction which occurs to the lowest row of retorts immediately over the
fire is avoided, and the flame and heat from the fuel on the grate is caused to
act more uniformly.
Having stated the nature of my Invention, I will now proceed, with the aid
of the accompanying Drawings, to describe that part of my Invention which
relates more specially to the peculiar construction of retort furnaces.
DESCRIPTION OF THE DRAWINGS.
A, A, A, A, are the double blocks of retorts, heated by the fires B, B, B, B,
placed parallel to the retort, as shewn in plan, Fig. 2, and transverse section,
Fig. 3. The products of combustion of the four fires, after heating the four

page_text: double blocks of retorts are carried away by the chimney C, the draught of
which is regulated by the two dampers D, D; E, E, are the walls dividing
the retort chambers, and supporting the ends of the retorts; F, F, ash-pits at
each end of the fire-place are provided for cleaning the furnace, and clearing
the bars.
Having now described the nature of my said Invention, and illustrated the
same by the accompanying Sheet of Drawings, I wish it to be understood
that I claim and desire to be secured to me by the herein in part recited
Letters Patent,―
Firstly, the addition of a sufficient quantity of sulphur vapour to the
sulphurous acid gas generated by the calcination of sulphuret of zinc to render
it economically available for the manufacture of sulphuric acid, either by
causing it to pass through chambers or kilns heated or not heated containing
sulphur or any metallic sulphuret.
Secondly, the mode of charging the sulphurous acid gas with additional
sulphur vapour by causing it to pass through a chamber containing sulphuret
of zinc, which is kept stirred or agitated without the admission of atmo-
spheric air.
Thirdly, the peculiar construction of retort furnaces for the reduction of
zinc ores, having a succession of fire-places in advance of a succession of blocks
of retorts.
And, lastly, the construction of the fire-place with its length parallel to the
retorts, as shewn in the accompanying Sheet of Drawings.
In witness whereof, I, the said Charles Crockford, have hereunto set
my hand and seal, this Twenty-seventh day of May, in the year of
our Lord One thousand eight hundred and sixty-seven.
Witness,
FREDERIC ROGERS,
19, Salisbury Street,
Strand.
CHARLES CROCKFORD. (L.S.)