IMPROVEMENTS IN UTILIZING CERTAIN COMPOUNDS PRODUCED IN THE PROCESS OF GALVANIZING IRON, AND IN THE APPLICATION OF THE SAME AND SIMILAR COMPOUNDS TO CERTAIN USEFUL PURPOSES
Year: 1854

page_text: LETTERS PATENT to William Hunt, of Tipton, in the County of Stafford,
Manufacturing Chemist, for the Invention of "IMPROVEMENTS IN UTILIZING
CERTAIN COMPOUNDS PRODUCED IN THE PROCESS OF GALVANIZING IRON, AND IN
THE APPLICATION OF THE SAME AND SIMILAR COMPOUNDS TO CERTAIN USEFUL
PURPOSES."
Sealed the 7th November 1854, and dated the 15th July 1854.
PROVISIONAL SPECIFICATION left by the said William Hunt at the
Office of the Commissioners of Patents, with his Petition, on the 15th
July 1854.
I, WILLIAM HUNT, of Tipton, in the County of Stafford, Manufacturing
Chemist, do hereby declare the nature of the Invention for "IMPROVEMENTS IN
UTILIZING CERTAIN COMPOUNDS PRODUCED IN THE PROCESS OF GALVANIZING IRON, AND
IN THE APPLICATION OF THE SAME AND SIMILAR COMPOUNDS TO CERTAIN USEFUL
PURPOSES," to be as follows:-
That my improvements may be well understood, I shall first describe the
ordinary mode of coating iron with zinc. An iron pot being set in brickwork,

page_text: with a fire-place under it, and flues, the pot is filled with the metal zine; a
fire is put under the pot to melt the metal, which being melted and heated to
the proper temperature, salammoniac is thrown over the surface of the metal,
which operates as a flux, covering the surface of the metal, to prevent oxidation
as much as possible, and also to facilitate the coating or galvanizing of the
iron, which is dipped into the melted metal. The iron, previous to being
dipped in the melted metal, is prepared for the dipping by first steeping it in.
dilute sulphuric or muriatic acid, and sometimes both; sometimes the iron is
washed in water after being thus steeped and dried in an oven; the iron is
then ready for dipping. The salammoniac is added to the metal from time to
time, on account of its volatilizing by the heat of the melted metal, but a con-
siderablo portion of the salammoniac is decomposed by the metallic zine,
making chloride of zinc. This effects a considerable loss of zinc. The chloride
of zinc is skimmed off from time to time as refuse, with some oxide of zinc,
which forms on the surface of the metal.
Having described the ordinary mode of and articles used in coating
iron with zinc, I wish it understood that I propose to employ chloride of
zine as a flux instead of using salammoniac; or chloride of zinc with a
little salammoniac may be used; my object being to substitute chloride of
zinc for salammoniac, to avoid the loss of zinc which now occurs by the
use of salammoniac; and further, because chloride of zinc can be obtained
much cheaper. This chloride of zinc being skimmed off occasionally, will
be a proper substance to be used as a flux again (after it has been dissolved
from the oxide of zinc), but it must be first boiled until all or nearly all
When the chloride of zinc has been
the water is evaporated from it.
washed from the oxide, the oxide may be used for making métallic zinc in
the usual way, or it may be used for other purposes. In the event of the oxide
being contaminated with chloride of zinc, I add caustic lime to decompose it,
and wash out the muriate of lime.
propose to steep the iron (to be
then dry it before dipping into
coated is steeped in dilute sul-
a considerable extent; but the
useless, even when it contains a
I recover the uncombined acid,
I also wish it to be understood that I
coated) in a solution of chloride of zinc,
the melted metal. When the iron to be
phuric acid, sulphate of iron is formed to
solution containing this is thrown away as
considerable quantity of free sulphuric acid.
and the sulphuric acid combined with the iron. In doing this, I boil the
liquor to a concentrated state in a lead pan or other suitable apparatus; then
I transfer it to a close furnace, where the temperature is sufficient to distill

page_text: over the free sulphuric acid, and ultimately the sulphuric acid is roasted off
from the iron; in this latter case a little air is admitted into the furnace. I
collect the sulphuric acid by sending the acid fumes into a condenser filled
with pebbles, and a little water is added from time to time to assist the con-
densation. The sulphuric acid thus obtained may be used again for cleansing
iron. The essence of my Invention consists in using chloride of zinc in place
of salammoniac in coating iron with zinc or other metals, and recovering the
sulphuric acid which has been used in cleaning the iron. Also, the use of a
solution of chloride of zinc for washing the iron in after cleaning and previous
to coating.