IMPROVEMENTS IN THE TREATMENT AND UTILIZATION OF THE WASTE SOLUTION OF SULPHATE OF IRON RESULTING PROVISIONAL RESULTING FROM THE CLEANSING OF IRON SURFACES IN THE PROCESS OF GALVANISING
Year: 1869

page_text: LETTERS PATENT to Frederick Braby, of Camberwell, in the County
of Surrey, for the Invention of "IMPROVEMENTS IN THE TREATMENT
AND UTILIZATION OF THE WASTE SOLUTION OF SULPHATE OF IRON RESULTING
PROVISIONAL SPECIFICATION left by the said Frederick Braby at the
Office of the Commissioners of Patents, with his Petition, on the
5th February 1869.
I, FREDERICK BRABY, of Camberwell, in the County of Surrey, do
hereby declare the nature of the said Invention for "IMPROVEMENTS
IN THE TREATMENT AND UTILIZATION OF THE WASTE SOLUTION OF SULPHATE OF
IRON RESULTING FROM THE CLEANSING OF IRON SURFACES IN THE PROCESS OF
GALVANISING," to be as follows:-
In the well-known process of galvanizing iron the sheets or surfaces
to be coated with zinc are cleansed by means of diluted sulphuric acid,

page_text: a crude solution of sulphate of iron being thus produced, which is
commonly thrown away as being useless. The present Invention con-
sists in improvements in the treatment of this solution by such methods
as to obtain certain useful products.
Ammoniacal vapour, which may be obtained by distillation from any
solution or liquid containing the same, is passed through an intermediate
washer or purifier of lime or baryta water into a vessel containing the
crude solution of sulphate of iron. By means of this treatment the
sulphate of iron and ammonia are brought into contact and a decompo-
sition ensues, the resulting oxide of iron being precipitated, and the
sulphate of ammonia remaining in solution. The latter is filtered and,
when necessary, purified by means of charcoal, and then run into large
evaporating pans for crystallization. The oxide of iron is washed and
calcined, and may be employed for the purification of illuminating gas
as a pigment, or may be reduced by the application of heat, as well
understood to a state of "crocus martis," "colcothar," or jewellers'
rouge.
Another mode of treating the crude solution of sulphate of iron is by
adding thereto scrap iron or finely powdered oxide of iron, and boiling
or digesting the same at a low temperature. The solution is then
mixed with a soluble salt of baryta or lead, whereby useful results are
obtained, the sulphate of baryta or lead being precipitated, and the salt
or salts of iron, as the chloride, acetate, or other compound, remaining
in solution.
SPECIFICATION in pursuance of the conditions of the Letters Patent, 2
filed by the said Frederick Braby in the Great Seal Patent Office on
the 31st July 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK
BRABY, of Camberwell, in the County of Surrey, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her 3
Letters Patent, bearing date the Fifth day of February, 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 suc-
cessors, give and grant unto me, the said Frederick Braby, Her special
licence that I, the said Frederick Braby, my exccutors, administrators, 3

page_text: and assigns, or such others as I, the said Frederick Braby, 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 THE
TREATMENT AND UTILIZATION OF THE WASTE SOLUTION OF SULPHATE OF IRON
RESULTING FROM THE CLEANSING OF IRON SURFACES IN THE PROCESS OF
GALVANIZING," upon the condition (amongst others) that I, the said
Frederick Braby, 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
date of the said Letters
months next and immediately after the
Patent.
NOW KNOW YE, that I, the said Frederick Braby, 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:-
In the well-known process of galvanizing iron the sheets or surfaces
to be coated with zinc are sometimes cleansed by means of diluted sul-
phuric acid, a crude solution of sulphate of iron being thus produced,
which is commonly thrown away as being useless, or else allowed to
crystallize into copperas.
My said Invention consists in improvements in the treatment of this
solution by such methods as to obtain cortain useful results. These
results are obtained by bringing ammoniacal liquor or vapour, which
may be obtained by distillation from any solution or liquid containing
ammonia, such as the waste liquor from gasworks, into contact with the
crude solution of sulphate of iron before mentioned.
In this Specifi-
cation gas liquor will be spoken of as the source of the ammonia.
One method by which this can be effected is as follows:-The gas
liquor is contained in a reservoir formed of metal or wood, or in a
receptacle prepared by excavating the ground and lining the sides and
bottom of such excavation with bricks faced with flat tiles, a bed of con-
crete being rammed in on the outside of the bricks. The reservoir
should have a low arched roof. The crude solution of sulphate of iron

page_text: is contained in a large wooden vat or tank, into which the ammoniacal
liquor is pumped, the same having been previously purified by lime or
baryta, as will be well understood by persons conversant with such opera-
tions. By this treatment the sulphate of iron and ammonia are brought
into contact and decomposition ensues, the sulphuric acid leaving the iron
and combining with the ammonia, producing sulphate of ammonia.
Sufficient time having been allowed for settlement, the sulphate of
ammonia is run out into filtering vessels, which may be advantageously
constructed of wood, and should be shallow, with perforated false
bottoms placed about two inches above the fixed bottoms and supported
by suitable means. On the false bottoms should be placed huckaback or
other strong draining cloth. The liquid sulphate of ammonia, after
draining through the cloth, is then allowed to run down by means of
pipes connected with each filter into large iron evaporating vessels, and
having been boiled down to the requisite consistency, is run into pans
(by preference lined with lead) and crystallized. If considered requisite
the liquid may, before being run into the evaporating vessels, be purified
by means of charcoal. The oxide of iron which remains on the filtering
cloths is well washed by means of water, and is then thrown on a flat
kiln which is suitably heated, whereby moisture and any sulphur and
carbonic acid which may have been held in combination are expelled.
The oxide of iron thus obtained may be employed for the purification of
illuminating gas as a pigment, or may be reduced by the application of
heat to a state of "crocus martis," "colcothar," or jewellers' rouge.
Another mode of procedure is to pump the ammoniacal liquor up
from the reservoir into a large iron still or boiler, which should be set in
brickwork. A quantity of lime is placed in the still in order to neu-
tralise the sulphuretted hydrogen, carbonic acid, or other impurities of
the gas liquor. Upon the application of heat (which may be advan-
tageously assisted by means of an agitator furnished with fans, and
caused to revolve within the still or boiler) the ammonia is liberated
in a gascous form, and passes through a pipe into a wooden or iron
vessel, which may be termed a washer or purifier, and which contains
lime and water at the bottom. A bent pipe conveys the ammonia to
nearly the bottom of the liquid, the lime contained in which is intended
to deprive it of any remaining sulphuretted hydrogen or other impurity.
The washer or purifier is a close vessel, and soon becomes full of the
gas,
which
passes thence through pipes into a vat or vats containing the

page_text: sulphate of iron. The washer is fitted with a false bottom perforated
with holes, which are larger and more numerous as they radiate from
the centre. A stirrer or agitator is placed underneath the false bottom,
the same being actuated by gearing from the top. Some aqueous vapour
may be admitted from the still or boiler with the ammoniacal gas or
vapour, but the same will be condensed in the washer. The washer is
provided with a safety pipe, and with a pipe which leads back into the
boiler, and also with a tap or taps to ascertain the height of liquid. The
decomposing vats are by preference made of fir, and should be strongly
hooped, and should be provided with perforated false bottoms placed at
about six inches distance from the bottoms of the vats, with the per-
forations increasing in size as they radiate from the inlet. The ammonia
enters through a tube, which conducts it under the false bottom, where
the decomposition commences. It then passes through the perforations
and spreads itself over the whole surface of the liquor. The vats may
be also furnished with stirrers. When perfect decomposition has taken
place the whole contents of the vats are, after a short time, run on to
the filters, as before described, and the ammoniacal solution run into
evaporating pans. When these are filled the surplus fluid can be
retained in a reservoir or tank. The process is then completed in the
manner herein-before described. When the lime in the washer becomes
impure, or ceases to have any power of causing chemical action, a plug
which is provided for that purpose is taken out and the mud run into
the still or boiler to be further used in decomposing the gas liquor. A
much larger quantity of gas liquor will generally be required than of
the iron solution, but this will depend upon the relative strength of the
ammoniacal liquor and the sulphate of iron under treatment. In the
above processes heat may be applied by means of hot air or steam pipes
to assist decomposition and evaporation.
In combination with either of the before-mentioned processes the
extraction of the ammonia from the gas liquor may be assisted by
blowing air through it, the ammonia and air being then driven into the
decomposing vats direct, or else passing on their way thither through
the washer or purifier, in accordance with the plan described in the
Specification of an Invention for which Letters Patent, bearing date the
Twenty-seventh day of June 1868, No. 2067, were granted to Isham
Baggs and myself. This mode of treatment, however, I do not claim
as being part of my present Invention.

page_text: Another mode of treating the crude solution of sulphate of iron is,
by adding thereto scrap iron or finely powdered oxide of iron, and
boiling or digesting the same at a low temperature. The solution is then
mixed with a soluble salt of baryta or lead, whereby useful results are
obtained, the sulphate of baryta or lead being precipitated, and the
salt or salts of iron, as the chloride, acetate, or other compound,
remaining in solution.
Having thus declared and ascertained the nature of my said Invention,
and the manner in which it is to be performed, I would observe in con-
clusion that what I consider novel and original, and therefore claim as
constituting the Invention secured to me by the said herein-before in
part recited Letters Patent are, the treatment and utilization of the
waste solution of sulphate of iron resulting from the cleansing of iron
surfaces in the process of galvanizing by means of the chemical reactions
herein mentioned, substantially as herein-before set forth and described.
In witness whereof, I, the said Frederick Braby, have hereunto set
my hand and scal, this Twenty-eighth day of July, in the year of
our Lord One thousand eight hundred and sixty-nine.