IMPROVEMENTS IN THE MANUFACTURE OF SALTPETRE
Year: 1858

page_text: LETTERS PATENT to William Edward Newton, of the Office of Patents,
66, Chancery Lane, in the County of Middlesex, Civil Engineer, for
the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF SALTPETRE."—
A communication.
Sealed the 6th July 1858, and dated the 6th May 1858.
PROVISIONAL SPECIFICATION left by the said William Edward Newton
at the Office of the Commissioners of Patents, with his Petition, on the
6th May 1858.
I, WILLIAM EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane,
in the County of Middlesex, Civil Engineer, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF SALTPETRE,'
to be as follows:-
This Invention of improvements in the manufacture of saltpetre is
based upon the greater affinity possessed by nitric acid for potash than for
soda, and the deliquescence of hydrate of soda, which allows of this hydrate
being separated from nitrate of potash (saltpetre) by simple washing.
In carrying out this Invention, potash is first rendered caustic by treating it
with about its own weight of newly slacked lime of good quality, and at least
ten times its weight of water, and keeping it boiling quickly in a closed vessel
until a small quantity, well precipitated or filtered, is no longer acted upon by
lime water. The potash lye thus obtained is to be allowed to settle and kept

page_text: from contact with the air, and decanted into a second closed vessel or boiler
containing a solution of nitrate of soda, which has been well clarified by being
allowed to settle in the vessel in which it was dissolved. The quantities of
potash and of nitrate of soda to be employed will depend upon the quality of
the primary matters procured in commerce, but they must be used in equi-
valent or atomic proportions. The contents of this second vessel, after the
desired chemical change has taken place, must be evaporated, so as to obtain
the greater portion of the saltpetre which is crystallized out of the solution by
cooling in a closed crystallizing vessel to which the boiling liquid is supplied
by means of a cock or valve adapted to the second boiler.
The mother liquor which still contains saltpetre is to be evaporated to a
high degree of concentration and again crystallized, and the solid matter thus
obtained must be well drained (free from contact with the atmosphere), and
may be a second time crystallized. The liquid portion remaining will be
found to consist of a strong solution of caustic soda, containing scarcely any
traces of saltpetre; this may, if required, be evaporated and run off, in order
to render it more portable.
Instead of washing out the alkali, it may be neutralized by the addition of
a few drops of very dilute nitric or hydrochloric acid, leaving traces of nitrate
of soda or chloride of sodium, the greater portion of which will run off in the
state of solution before the saltpetre is carried to the drying apparatus.
By the above process saltpetre may be at once obtained in a state of great
purity, the refining process being dispensed with, and as an accessory product
caustic soda will be found as a residuum after the process is complete.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Edward Newton in the Great Seal Patent Office on
the 6th November 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane, in the County
of Middlesex, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixth day of May, in the year of our Lord One
thousand eight hundred and fifty-eight, in the twenty-first year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the
said William Edward Newton, Her special license that I, the said William
Edward Newton, my executors, administrators, and assigns, or such others as

page_text: I, the said William Edward Newton, my executors, administrators, or 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 MANUFACTURE OF SALTPETRE," being a communication
from abroad, upon the condition (amongst others) that I, the said William
Edward Newton, by an instrument in writing under my hand and seal, 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 William Edward Newton, do hereby
declare the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement, reference being had to the Drawing hereunto annexed,
and to the letters and figures marked thereon (that is to say):-
This Invention of "Improvements in the Manufacture of Saltpetre" is
based upon the greater affinity possessed by nitric acid for potash than for
soda, and the deliquescence of hydrate of soda which allows of this hydrate
being separated from nitrate of potash (saltpetre) by simple washing.
In carrying out this Invention, potash is first rendered caustic by treating it
with about its own weight of newly slacked lime, of good quality, and at least
ten times its weight of water, and keeping it boiling quickly in a closed vessel
until a small quantity well precipitated or filtered is no longer acted upon by
lime water. The potash lye thus obtained is to be allowed to settle, and kept
from contact with the air, and decanted into a second closed vessel or boiler
containing a solution of nitrate of soda which has been well clarified by being
allowed to settle in the vessel in which it was dissolved. The quantities of
potash and of nitrate of soda to be employed will depend upon the quality of
the primary matters procured in commerce, but they must be used in equi-
valent or atomic proportions. The contents of this second vessel, after the
desired chemical change has taken place, must be evaporated so as to obtain
the greater portion of the saltpetre which is crystallized out of the solution, by
cooling in a closed crystallizing vessel to which the boiling liquid is supplied
by means of a cock or valve adapted to the second boiler.
The mother liquor, which still contains saltpetre, is to be evaporated to a
high degree of concentration, and again crystallized, and the solid matter thus
obtained must be well drained (free from contact with the atmosphere), and

page_text: may be a second time crystallized. The liquid portion remaining will be found
to consist of a strong solution of caustic soda, containing scarcely any traces of
saltpetre; this may, if required, be evaporated and run off in order to render
it more portable.
Instead of washing out the alkali, it may be neutralized by the addition of
a few drops of very dilute nitric or hydrochloric acid, leaving traces of nitrate
of soda or chloride of sodium, the greater portion of which will run off in the
state of solution before the saltpetre is carried to the drying apparatus.
By the above process, saltpetre may be at once obtained in a state of great
purity, the refining process being dispensed with, and, as an accessory product,
caustic soda will be found as a residuum after the process is complete.
The several Figures in the accompanying Drawing represent the arrange-
ment of apparatus which the Inventor prefers to employ for carrying this
Invention into effect. Fig. 1 being a side elevation of the apparatus; and
Fig. 2 a plan view of the same. The other Figures shew some of the parts
detached.
A is a vessel for slacking and decanting off the lime; it is provided with
a valve at a, Fig 1, and also with a pipe leading to the vessel D. B, Fig. 2,
is a vessel in which the nitrate of soda is dissolved and allowed to settle; it is
provided with a pipe leading to the evaporating boiler or vessel E. C, Fig. 2,
is a vessel in which potash (of commerce) is placed, together with such a
quantity of water as will not be sufficient to dissolve any considerable quantity
of the neutral salts contained therein; a pipe similar to those above-mentioned
leads from this vessel C to the boiler D. The vessel C is not necessary when
it is not required to obtain either saltpetre or caustic soda of great purity, and
when this vessel is dispensed with the potash is introduced directly into the
caustifying boiler D, through the man-hole b, Fig. 1, which is suitably pro-
vided with a trap or cover for that purpose. The boiler D is set over a furnace,
but is also partially heated by a steam jacket leading from the boiler E. The
pipe c conducts the water of condensation from this steam jacket into the
washing apparatus S, Fig. 1, and shewn detached in transverse section at Fig. 3.
The waste steam escapes by the steam pipe d, (Fig. 1) into the atmosphere.
The boiler D is provided with a cock or valve e of peculiar construction
(shewn detached and on an enlarged scale, at Fig. 4), for the purpose of
drawing off the clear lye into the vessel E, when a sufficient quantity of
carbonate of lime has been deposited. This cock differs from ordinary cocks,
inasmuch, as its hinder part projects some distance into the interior of the
boiler, and to the projecting part f, a bent pipe is attached as shewn at Fig. 4,
in such a manner as to be capable of being set at any inclination, and thus

page_text: present its open end g at any required distance from the surface of the con-
tents of the vessel D, so that the open end of the pipe may be gradually
lowered as the quantity of fluid contained in the vessel D diminishes. The
open end g of this tube is provided with a stopper h, having a rod projecting
above the surface of the liquid to prevent the entrance of any solid matters or
sediment inside the tube.
The boiler D is also provided with a valve i, Fig. 1 for emptying the pasty
contents therefrom into the washing apparatus S.
E is a boiler, also provided with a man-hole, and in which the clarified
nitrate of soda and the clear potash lye are evaporated to the degree required
for obtaining by crystallization about five-sixths of the saltpetre produced by
the reaction which takes place. This boiler communicates, by means of the
cock j, with a rectangular vessel F, surrounded by masonry or brickwork,
and having a double air valve at top. In this vessel the solution is allowed to
remain until perfectly settled. A screw valve k fixed at a little distance above
the bottom of this vessel F, serves to draw off the liquor into the shallow
crystallizing vessel H. The vessel F is provided at its lower part with another
vessel G, which is separated from it by means of a false bottom, and serves to
receive the sediment through the cock when its level approaches near to the
cock or valve k above mentioned. This may be ascertained by drawing off
every day a few drops of the liquid through the small cock m placed for that
purpose a little lower than the cock k, leading to the crystallizing vessel. The
chamber G is provided with a cock n for drawing off its contents.
The crystallizing vessel H consists of a large shallow vessel with a flat
bottom and is provided with a removeable cover, and is mounted upon trunnions
h, the one set a little lower than the other, so that the cock or valve situate
at o shall always be at the lowest point when the vessel is tilted. This
arrangement will prevent the mother liquor from remaining in the part o, p,
when the crystallizing vessel is inclined, the mother liquor being allowed to
escape through the cock and funnel q, Fig. 1, into the receptacle I,
underneath.
The saltpetre on being removed from the crystallizing vessel H is left to
drain in closed vessels J, having perforated bottoms, (shewn detached at
Figures 5) which are placed upon or over the openings or holes r, r, (Fig. 2).
The saltpetre is to be treated several times with water, which will wash out
the caustic soda lye from it. Beneath the openings r, r, is a waste pipe leading
to the receptacle I. All the above named vessels and parts are to be made
of iron.
K (Figures 6) is a copper pan for washing the saltpetre in the quantity of

page_text: acidulated water necessary for neutralizing any free alkali contained in it; L
is an apparatus for raising the saltpetre to the drying apparatus; M is a
second evaporating vessel (of iron) for the concentration of the mother liquors
which are raised for that purpose from the receptacle I, by the pump N. This
evaporating vessel is provided at s with a cover and steam pipe, and also with
a pipet for the escape of the water of condensation. When the liquor is
sufficiently concentrated, it is allowed to escape through the cock u, into the
crystallizing vessel O, which is mounted in the same way as the first large one
H. The lye passes from the crystallizing vessel O, through the cock v, and
funnel w, into the receptacle P; Q (Fig. 2) is a small iron pan or boiler,
for the evaporation of the lye; it is provided also with a steam escape pipe
and a pipe for the escape of the water of condensation.
R (Fig. 1) is a drying apparatus composed of a large iron tray or trough
with raised sides, under which circulates the steam from the boilers D and E,
and which is conducted thereto by the pipe x, adapted for that purpose to the
main steam pipe y. By means of the valves 1, 2, 3, the steam may be
directed either round the boiler D, or under the drying trough R, or out into
the atmosphere through the opening y.
The washing apparatus S (represented in longitudinal section at Fig. 1, and
detached in transverse section at Fig. 3), is composed of a vessel rounded at
bottom, and in which is mounted a shaft a', worked by means of a handle 6'; upon
this shaft are set a number of T-shaped beaters c¹, c¹, c', which serve to agitate
the carbonate of lime in the washing water conducted thereto by means of the
pipe d', the carbonate of lime escaping through the waste cock e¹ below.
T are the reservoirs for the washing water, to which it is supplied by means
of bent or forked pipes f¹, which are provided inside the washing apparatus
with decanting cocks similar to that above described. There are two of these
reservoirs, one only of them being shewn in the Drawing, the other one being
situate behind it. They are intended to receive the water alternately before
it is supplied by the pump U, to either one of the vessels A, B, or C. The
suction pipe g of the pump is forked, each branch being provided with a cock
in order to supply one or other of the reservoirs as required. The supply
pipe is also furnished with cocks in order to supply water to any of the vessels
above where it may be required. In Fig. 1, V is an iron tube or funnel for
conducting the saltpetre as it comes from the drying apparatus R, into barrels
or other suitable receptacles placed below for the purpose.
Having now described the nature of this Invention, and the manner of
carrying the same into effect, as communicated to me by my foreign cor-
respondent, I desire it to be understood, that I do not claim under the above

page_text: in part in recited Letters Patent, the employment for the production of salt-
petre, either of potash or nitrate of soda, those substances having been before
used for that purpose, but what I claim is,-
Firstly, the manner above described of employing those substances, that is
to say, the perfect caustification of the potash, which is brought into the
presence of nitrate of soda, in equivalent or atomic proportions in a closed
vessel; the new or improved process being based upon the greater affinity
possessed by nitric acid for potash than for soda, and upon the deliquescence of
hydrate of soda, which allows of the perfect separation of this hydrate from the
nitrate of potash by simple washing.
Secondly, I claim the arrangement of apparatus above described and repre-
sented in the Drawing, or any mere modification thereof, by which the above
operations are conducted in closed vessels instead of in open vessels as hereto-
fore, by which means the carbonic acid contained in the atmosphere, is
prevented from decaustifying the product, and whereby the refining process
usually required is dispensed with.
In witness whereof, I, the said William Edward Newton, have hereunto
set my hand and seal, the Sixth day of November, in the year of our
Lord One thousand eight hundred and fifty-eight.
Witness,
J. W. MOFFATT,
66, Chancery Lane.
W. E. NEWTON. (L.S.)