IMPROVEMENTS IN TREATING PRODUCTS OBTAINED WHEN COATING IRON WITH ZING
Year: 1865

page_text: LETTERS PATENT to James Graham, of Manchester Road, Warrington,
in the County of, Lancaster, for the Invention of "IMPROVEMENTS IN
TREATING PRODUCTS OBTAINED WHEN COATING IRON WITH ZING."
Sealed the 25th July 1865, and dated the 18th February 1865.
of the Commissioners of Patents, with his Petition, on the 18th February
1865.
I, JAMES GRAHAM, of Manchester Road, Warrington, in the County of
Lancaster, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN TREATING PRODUCTS OBTAINED WHEN COATING IRON WITH ZINC," to be as
follows:-
This Invention has for its object improvements in treating products obtained
when coating iron with zinc.
The products to which my Invention relates are flux skimmings or dross
removed from the surface of the melted zinc. The other product is that
known as "dross spelter" or "spelter dross" which subsides to the bottom of
the bath of melted zinc when coating iron with zinc.. In treating the flux dross
or skimmings-they are first crushed by edge runners or otherwise, and the

page_text: product is placed with water into an open vessel of wood having a false bottom,
which by preference is of wicker work. Free steam is blown into this vessel
so as to cause the water to boil, and in this manner the soluble parts of the
flux dross or skimmings are dissolved; after allowing time for a subsidence the
solution is drawn off and is run into a suitable vat. The chloride and oxide of
zine are precipitated by an alkali, using by preference for that purpose soda
ash or lime if it be desired to obtain liquor ammonia. The liquor when
precipitated by soda ash is drawn off from the vat into a vessel lined with
lead and capable of being closed. From this vessel or its cover a leaden pipe
proceeds into another vessel also lined with lead. The vessel containing the
liquor is heated by steam externally in a jacket or by a steam coil internally,
by which the ammonia is distilled over into the second vessel where there is
water acidulated with muriatic acid. The product thus obtained is heated in
order to evaporate and concentrate the muriate of ammonia which crystallizes.
When liquor ammonia is desired and the solution obtained has been precipi-
tated by lime as above mentioned, the liquor ammonia is distilled over into a
glass or other suitable vessel and is afterwards redistilled. In treating "dross
spelter" or "spelter dross" the same is broken or cut in pieces when
necessary, and then the spelter is distilled off in a spelter furnace, using pots
or muffles similar in form to what are known as Silesian muffles used in the
reduction of zinc ores into spelter; but in place of the muffles or pots having
flat bottoms they are made with bottoms highest at the back and inclining
towards the front. The dimensions of such muffles may be varied, but I
prefer that they should be about two feet six inches long, seven inches wide on
the inside, and fifteen inches high with an incline of about four inches from
back to front, by which the liquid dross is retained in the muffle till the spelter
is distilled over.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Grabam, in the Great Seal Patent Office on the 18th
August 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, 1, JAMES
GRAHAM, of Manchester Road, Warrington, in the County of Lancaster,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighteenth day of February, in the year of our Lord
One thousand eight hundred and sixty-five, in the twenty-eighth year of Her

page_text: reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said James Graham, Her special licence that I, the said James Graham,
my executors, administrators, and assigns, or such others as I, the said James
Graham, 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 TREAT-
ING PRODUCTS OBTAINED WHEN COATING IRON WITH ZINC," upon the condition
(amongst others) that I, the said James Graham, my executors or adminis-
trators, 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 James Graham, 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 :-
This Invention has for its object improvements in treating products
obtained when coating iron with zinc. One of the products to which my
Invention relates is chloride of flux skimmings or dross removed from the
surface of the melted zinc. In treating the flux dross or skimmings they
are first crushed by edge runners or otherwise, and the product is placed with
water into an open vessel of wood having a false bottom, which by preference
is of wickerwork. This vessel may be made about eight feet deep and of any
convenient diameter, and the wickerwork is placed about a foot from the
bottom. On the false bottom a layer of crushed flux skimmings about four
feet thick is laid, and the vessel is filled up with water to about one foot over
the top of the flu skimmings, and so it is allowed to stand for a day or two.
This first water is then run off clear by a cock placed under the false bottom,
and another similar quantity of water is run on to the charge; free steam is
then blown into the vessel under the false bottom so as to cause the water
to boil, and in this manner the remaining soluble parts of the flux dross or
skimmings are dissolved. After allowing time for a subsidence the solution
is drawn off and the vessel is a third time charged with water to wash the
residue; this water after some hours is in turn run off. The three decoctions
thus obtained are mixed in a suitable vat, and here the zinc is precipitated.
as oxide by an alkali, using by preference for that purpose soda ash. This

page_text: vat is furnished with a cover to prevent the escape of ammoniaca fumes, and
a shaft with stirring arms upon it passes down through the centre of the
cover into the vat, and the stirrer is employed thoroughly to mix the alkali with
the liquid. Enough alkali is used to set free all the ammonia contained in the
liquid. The liquor when precipitated by soda ash is drawn off from the vat
into a still or close boiler, from which a pipe leads to a receiver containing
water acidulated with muriatic acid, the pipe which conveys the ammonia
from the still terminates at the surface of the weak acid. Two or more acid
vessels may conveniently be employed. The strength of the acid water is
conveniently such that the solution of chloride of ammonium obtained by its
saturation may be tolerably concentrated, but yet not so much as to be likely
to solidify in the vessel and so prevent the precipitation of the zinc. When
the liquid in the absorption vessels becomes saturated, or nearly so, it is drawn
off and concentrated by evaporation, and the muriate of ammonia is crystallized
out. The distillation is stopped as soon as ammonia ceases to come over.
When liquor ammonia only is desired the solution may be precipated by lime;
the liquor ammonia is distilled over in vessels suitably cooled exteriorly.
I claim as respects this part of my Invention the treating a solution obtained
from flux skimmings with an alkali or alkaline earth, and afterwards distilling
off the ammonia as described.
I also, according to my Invention, treat "dross spelter" or "spelter dross," the
material which subsides to the bottom of the bath from melted zinc when it is
used to coat iron with zinc.
In treating "dross spelter" or "spelter dross" to recover spelter from it,
the same is broken or cut in pieces when necessary, and then the spelter is
distilled off in a spelter furnace, using pots or muffles similar in form to
what are known as Silesian muffles used in the reduction of zinc ores into
spelter.
The muffle I employ is about two feet six inches long, seven inches wide,
and fifteen inches high; it is closed at one end and open at the other, but at the
open end is an incline rising four or five inches in height from the bottom, so that
the spelter dross when melted may not run out of the muffle. The muffle
is built up in a furnace so that it can be heated to a white heat. The open
end of the muffle is, after the charge is introduced, closed by a slab made of
dried clay, and luted on. At the other or closed end of the muffle a receiver
is luted in, a hole being made for it at the top of the closed end of the muffle.
This receiver, which is exterior of the furnace, is a tube or vessel of burnt clay;
it may be similar in sectional form to the muffle and about two feet four
inches long, five inches wide, and six inches high. In the centre portion of

page_text: this receiver, in the flat bottom thereof is a hollow about eighteen inches long
and a few inches deep, sufficient to contain about 40lbs. of spelter. A charge
of about 40 or 45 lbs. of spelter dross is put into the muffle and the open
end is then closed and luted up as already described, and a stopper is put into
the open end of the receiver; it is luted in, a small hole only being left for
the escape of the gases, and this hole must be continually kept open by
passing a wire through the said hole into the muffle. The muffle is then
heated nearly to a white heat and the spelter distils over and accumulates
in a liquid state in the hollow from whence from time to time it is raked out
into a ladle and it is then cast into moulds.
I claim as respects this part of my Invention the recovery of spelter
from spelter dross by distilling the spelter therefrom as herein-before
described.
In witness whereof, I, the said James Graham, have hereunto set my hand
and seal, this Sixteenth day of August, in the year of our Lord One
thousand eight hundred and sixty-five.
JAMES GRAHAM.
(L.S.)