IMPROVEMENTS IN UTILIZING THE AMMONIACAL SKIMMINGS OBTAINED IN GALVANIZING IRON
Year: 1869

page_text: LETTERS PATENT to John Pattinson, of Newcastle-on-Tyne, in the
County of Northumberland, Analytical Chemist, for the Invention
of "IMPROVEMENTS IN UTILIZING THE AMMONIACAL SKIMMINGS OBTAINED IN
GALVANIZING IRON."
Scaled the 2nd October 1869, and dated the 8th April 1869.
CIFICATION felt by the said Jolm Lattinson at the
Office of the Commissioners of Patents, with his l'etition, ou the
8th April 1869.
I, JOHN PATTINSON, of Newcastle-on-Tyne, in the County of
Northumberland, Analytical Chemist, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN UTILIZING THE AMMONIACAL
SKIMMINGS OBTAINED IN GALVANIZING IRON," to be as follows:-
I, JOHN PATTINSON, of Newcastle-on-Tyne, in the County of
Northumberland, Analytical Chemist, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN UTILIZING THE AMMONIACAL
SKIMMINGS OBTAINED IN GALVANIZING IRON," to be as follows:-

page_text: bye-product of the manufacture of galvanized iron, consisting principally
of a mixture of chloride of zinc, oxychloride of zinc, oxide of zinc,
metallic zine, and chloride of ammonium.
Hitherto it has been customary to convert this material into zinc
oxide by calcination, which mode of treatment occasions the loss of the
zinc existing as chloride, and part of the zinc existing as oxychloride,
and also of the chloride of ammonium.
My Invention is designed to avoid this loss of the zine existing in the
skimmings as chloride and oxychloride, in which state it is liable to be
volatilized in the process of calcining hitherto commonly practised; and
my Invention also enables me to recover the ammonia from the chloride
of ammonium existing in the skimmings. To attain these ends I reduce
the skimming to powder, and mix with it sufficient powdered lime or
other suitable alkaline earth to decompose the chloride of zinc, oxy-
chloride of zinc, and chloride of ammonium existing in the skimming.
I put a suitable charge of this mixture into a retort or into a furnace,
and apply heat thereto, so as to decompose the chloride of zinc, oxy-
chloride of zinc, and chloride of ammoniumi before mentioned. By this
operation the ammonia contained in the skimmings is volatilized as
ammoniacal gas; and if it be intended to utilize this the aperture of the
retort must communicate by means of pipes with suitable vessels for
condensing the ammonia in water, so as to form liquid ammonia, or the
ammonia may be made to combine with sulphuric or other acid, so as to
form sulphate of ammonia or other ammoniacal salt. After this treat-
ment the charge is withdrawn from the retort or furnace, and is
lixiviated with water so as to dissolve out the chloride of calcium or
other alkaline earth chloride formed during the subjection of the
mixture to heat. The washed residue, which contains all the zinc of
the sal-ammoniac skimmings under treatment in the state of oxide, may
then be dried and the zinc extracted from it by smelting in the usual
manner.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Pattinson in the Great Seal Patent Office
on the 8th October 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, 1, JOHN
PATTINSON, of Newcastle-on-Tyne, in the County of Northumberland,
Analytical Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighth day of April, in the year
of our Lord One thousand eight hundred and sixty-nine, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Pattinson, Her special licence that I,
the said John Pattinson, my executors, administrators, and assigns, or
such others as I, the said John Pattinson, 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,
UTILIZING THE
and Isle of Man, an Invention for "IMPROVEMENTS IN
AMMONIACAL SKIMMINGS OBTAINED IN GALVANIZING IRON,"
the condition
(amongst others) that I, the said John Pattinson, 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.
upon
NOW KNOW YE, that I, the said John Pattinson, 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 (that is to say):-
My Invention relates to an improved mode of treating the material
known as "ammoniacal skimmings" or "sal-ammoniac skimmings,"
which is a bye-product of the manufacture of galvanised iron, consisting
principally of a mixture of chloride of zinc, oxychloride of zinc, oxide of
zine, metallic zinc, and chloride of ammonium.
Hitherto it has been customary to convert this material into zinc
oxide by calcination, which mode of treatment occasions the loss of the

page_text: zinc existing as chloride, and part of the zinc existing as oxychloride,
and also of the chloride of ammonium.
My Invention is designed to avoid this loss of the zinc existing in the
skimmings as chloride and oxychloride, in which states it is liable to be
volatilized in the process of calcining hitherto commonly practised; and
my Invention also enables me to recover the ammonia from the chloride
of ammonium existing in the skimmings. To attain these ends I reduce
the "skimmings" to powder and mix with it sufficient powdered lime or
other suitable alkaline earth to decompose the chloride of zinc, oxy-
chloride of zinc, and chloride of ammonium existing in the "skimming."
As the skimmings are of variable composition it is necessary first to
ascertain the amount of chlorine contained in that to be brought under
treatment in order to determine what proportion of lime or other alkaline
earth is required for the decomposition of the chlorides and oxychloride.
For every thirty-five parts of chlorine contained therein about twenty-
eight parts of unslaked lime, or about thirty-seven parts of slaked lime,
or an equivalent quantity of other alkaline earth, should be provided
and mixed with the "skimming." A suitable charge of this mixture I put
into a retort or into a furnace and apply heat thereto so as to decompose
the chloride of zinc, oxychloride of zinc, and chloride of ammonium
before mentioned. By this operation the ammonia contained in the
skimmings" is volatilized as ammoniacal gas. If it be intended to utilize
this gas the aperture of the retort must communicate by means of pipes
with suitable vessels for condensing the ammonia in water so as to form
liquid ammonia; or the ammonia may be made to combine with
sulphuric or other acid so as to form sulphate of ammonia or other
ammoniacal salt. When treating the skimmings "with the view to
collecting the ammonia the mixture of " skimmings "and lime or other
alkaline earth is placed in a retort (which may be similar to a gas retort)
and heated until the evolution of ammonia has ceased. I find that a
temperature somewhat below a dull red heat is generally sufficient to
effect the necessary decomposition. After this treatment the charge is
withdrawn from the retort or furnace and is lixiviated with water, so as
to dissolve out the chloride of calcium or other alkaline earth chloride
formed during the subjection of the mixture to heat. The washed
residue, which contains all the zinc of the sal-ammoniac skimmings
under treatment in the state of oxide, may then be dried and the ziuc
extracted from it by smelting in the usual manner.
"

page_text: Having now set forth the nature of my Invention of "Improvements
in Utilizing the Ammoniacal Skimmings obtained in Galvanizing Iron,"
and explained the manner of carrying the same into effect, I wish it to
be understood that under the above in part recited Letters Patent I
claim, heating galvanizer's ammoniacal skimmings in the presence of
lime or other equivalent alkaline earth and subsequently washing the
heated residue, as and for the purpose above described.
In witness whereof, I, the said John Pattinson, have hereunto set
my hand and seal, the Twenty-ninth day of September, in the
year of our Lord One thousand eight hundred and sixty-nine.
JOHN PATTINSON. (L.S.)