IMPROVE- MENTS IN THE MANUFACTURE OF SULPHATE, OF MURIATE, AND OTHER SALTS OF AMMONIA
Year: 1844

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
WATSON, Junior, of Leeds, in the County of York, Manufacturing Chemist,
send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Sixteenth day of January, in the seventh year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
William Watson, Her especial licence, full power, sole privilege and autho-
rity, that I, the said William Watson, my executors, administrators, and
assigns, and such others as I, the said William Watson, my executors,
administrators, or assigns, should at any time agree with, and no others,
from time to time and at all times during the term of years therein mentioned,
should and lawfully might make, use, exercise, and vend, within England,
Wales, and the Town of Berwick-upon-Tweed, my Invention of "IMPROVE-
MENTS IN THE MANUFACTURE OF SULPHATE, OF MURIATE, AND OTHER SALTS OF
AMMONIA;" in which said Letters Patent is contained a proviso obliging me,
the said William Watson, by an instrument in writing under my hand and
seal, particularly to describe and ascertain the nature of my said Invention,
and in what manner the same is to be performed, and to cause the same
to be enrolled in Her Majesty's High Court of Chancery within six calendar
months next and immediately after the date of the said in part recited Letters
Patent, as in and by the same, reference being thereunto had, will more fully
and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
William Watson, do hereby declare that the nature of my said Invention,
and the manner in which the same is to be performed, are particularly described
and ascertained in and by the following description thereof, reference being
had to the Drawings hereunto annexed, and to the letters and figures marked
thereon, that is to say :-
It is well known to all persons conversant with the manufacture of the salts
of ammonia, that the nuisance attending such manufacture is a very great
annoyance to the surrounding neighbourhood; one of the principal objects,
therefore, of my Invention, is to obviate, or, at any rate, to lessen this incon-
venience. Various other advantages, which will be hereafter mentioned, will
result from the use of my improvements, which consist, in the first place, in
evaporating ammoniacal liquor in close vessels, and passing the vapour or
steam of such liquor through an acid solution for the purpose of producing a
salt, instead of adopting the usual method of mixing the ammoniacal liquor
and the acid together, and then evaporating it in open vessels to obtain the
salt in crystals.
And, secondly, in evaporating in close vessels the ordinary mixture of
ammoniacal liquor and acid, whereby the obnoxious gases are or may be
collected and prevented from dispersing in the surrounding atmosphere.
These are the principles upon which my Invention or discovery is founded;
it will, however, be obvious to any person conversant with the manufacture,
that the mode of operating will be somewhat different, according to the parti-
cular salt that is required to be produced; but still it will remain so essentially
similar in principle as will obviate the necessity of entering upon a minute
description of the process in connection with every salt. It may be here
observed that the various parts of the apparatus must be constructed of such
materials as will resist the action of the acids to be employed. In the accom-
panying sheet of Drawing I have shewn various views of certain arrangements
of apparatus which I have found to answer the purpose of manufacturing
sulphate of ammonia exceedingly well.
Fig. 1 represents a section of the simplest form of apparatus which I should
recommend if economy is a principal object, and if it is not particularly
necessary to produce a very pure salt or to avoid all nuisance. By means of
this apparatus, however, a finer salt can be produced, and the nuisance
attending the operation when the common method is adopted, is nearly
altogether obviated. In this figure A is an iron boiler partly filled with gas
water, or, as it is sometimes called, gas liquor or ammoniacal liquor. About
260 gallons of the liquor are supplied to the boiler, and a quantity of slacked

page_text: lime may or may not be added, at the discretion of the operator. It may,
however, be observed that the operation is hastened by its addition, and the
salt is much purer. A bent pipe or tube B connects the boiler with a leaden
vessel C, which is open at top. This vessel C is partly filled with sulphuric
acid (if sulphate of ammonia is required) in the proportion of about one
pound's weight of sulphuric acid of the specific gravity of 1,700 to every gallon
of liquor. This acid must be diluted with from three to four times its weight
of water. When the apparatus is ready charged with ammoniacal liquor and
dilute acid, as above mentioned, heat is applied to the boiler A, and at first
volatile and apparently incondensable gases pass through the pipe B into the
acid solution in the vessel C. The heat being continued, ammonia and steam
proceed from the boiler into the vessel C through small perforations made in
the inverted funnel at the end of the pipe B, and the ammonia coming into
contact with the acid immediately combines with it, and its further progress is
arrested; but the steam which comes over with the ammonia soon raises the
temperature of the acid solution in the vessel C, and will then escape there-
from uncondensed, so that the bulk of the liquor in the vessel is not materially
increased. When all the acid in the vessel C is completely neutralized, or, in
other words, when the liquor is well saturated with ammonia, the contents of
the vessel C may be allowed to settle for a short time, and then drawn off by
the syphon D into another vessel E, which is made of lead, or lined with lead,
and there it is left to crystallize. Supposing this to have been one day's opera-
tion, the crystals will form during the night, and the mother liquor may be
drawn back again into the vessel C, and supplied with more acid for a second
operation, before commencing which the boiler A must be emptied by means
of the aperture F, and replenished with fresh ammoniacal liquor.
A more
complete form or arrangement of apparatus is shewn at Fig. 2, which repre-
sents a longitudinal section of the apparatus in which the escape of noxious or
disagreeable vapours is, to a great extent, if not entirely prevented. The
boiler containing the ammoniacal liquor is seen at A, and B is the pipe for
conducting the vapours from the boiler to the leaden vessel C, which in this
instance is close at top. I put from 250 to 280 gallons of gas liquor into the
boiler and into the leaden vessel C, as many pounds of sulphuric acid of the
specific gravity above mentioned as gallons of gas water in the boiler. This
acid is diluted with about 3 or 4 times its volume of water; and if it is thought
desirable to add slacked lime to the ammoniacal liquor in the boiler A, I
supply about one hundredweight of lime for every 220 gallons of liquor.
The leaden vessel C is charged by means of the funnel G, and the uncondensed
steam and gases are carried off therefrom by the pipe II, and are made to

page_text: traverse a bent pipe I in the flat vessel J, which is shewn detached and in plan
at Fig. 3. The end of the pipe I is connected to another pipe, which descends
into a small vessel K, which, having a stream of cold water continually passing
through it, causes the steam and obnoxious vapours to be entirely condensed
instead of being diffused or allowed to escape into the surrounding atmosphere.
When the acid in the vessel C is neutralized, it is drawn off into the vessel L;
and after it has been allowed to settle, it is drawn off into another vessel or
reservoir M, where it is allowed to remain until other impurities have subsided.
It is then pumped up as it is found convenient, and at the discretion of the
operator, into the flat vessel J, where it is partially evaporated by the beat of
the steam, which is passed from the acid vessel C through the bent pipe I.
The concentrated solution is then let off into the crystallizing vessel N, and a
crop of fine, clean, and beautiful crystals may be obtained, which should be
placed on the inclined drainer O to dry.
I shall now describe the second part of my Invention, the object of which
is merely to obviate or considerably diminish the nuisance which arises from
the manufacture of salts of ammonia when they are made from gas water. In
the manufacture of sulphate of ammonia it is common to neutralize the gas
water with sulphuric acid, and in the manufacture of muriate of ammonia,
to use muriatic acid or muriate of lime. In any of these cases an impure
solution of an ammoniacal salt is obtained, which furnishes crystals by evapora-
tion. Now it is the evaporation and dispersion of the obnoxious vapours
in the air which causes the nuisance to the surrounding neighbourhood, and
to obviate this I employ a close vessel or boiler; and the steam and obnoxious
vapours which are driven off by evaporation, instead of being allowed to escape
into the open air, are confined and conducted through pipes or vessels, which
are kept at a low temperature by an external application of cold water, or other
means, and are thereby condensed in a manner similar to the common methods
of distillation, as shewn at Fig. 4, and, being thus brought into a liquid form,
may be more conveniently disposed of. The solution of ammoniacal salts,
which is formed by mixing the gas liquor with any acid, is put into the boiler
A, and, heat being applied thereto, the steam or vapors arising therefrom will
be driven off through the pipe B into the worm or bent tube in the vessel Q
below, which is kept constantly supplied with a stream of cold water, by which
means the vapors are condensed and prevented from dispersing; or, instead of
passing the steam and vapors through a bent pipe or worm, in the manner
just described, I conduct them from the boiler into a vessel similar to that
shewn at K in Fig. 2, which, being supplied with a stream of cold water that
is constantly flowing through it, accomplishes the same object, namely, the

page_text: condensation of the steam and vapors arising from the boiler. If thought
preferable, the boiler may be first charged with the proper quantity of ammo-
niacal liquor, and the acid solution poured into it in small quantities through
the funnel P. This, however, is left entirely to the discretion of the operator.
When the liquor in the boiler is sufficiently concentrated by the evaporation
of a portion of its aqueous particles, it is drawn off through the aperture T
into any convenient vessel, where it is crystallized.
The principal advantages resulting from the employment of the first part
of my improved process and apparatus are,-
First, a considerable saving in fuel, as by the improved process it is not
necessary to evaporate more than about one half of the ammoniacal liquor
from which the salts are obtained, as the ammonia, being more volatile than
the other ingredients, consequently escapes first.
Second, the operation being carried on in closed vessels instead of open ones,
as is generally the case, I consequently effect a saving in the product, as, when
open vessels are employed, some of the salt is volatilized and lost.
Third, instead of an impure and discolored salt, as is produced by the old
process, I am enabled to obtain a clean salt of considerable purity.
Fourth (and this advantage belongs also to the second part of my Inven-
tion), the preventing of the nuisance arising from the escape of noxious gases,
as is the case in the ordinary mode of manufacturing ammoniacal salts.
When salts of a more volatile nature than sulphates, such as muriates, are
required, care must be taken to keep the acid vessel C cool by surrounding it
with a
jacket of cold water, or by other means. The arrangement of
some of the other parts of the apparatus will also require to be somewhat
altered to meet the peculiar circumstances of the case as will be well
understood.
Having now described my Invention or improvements, and the manner of
carrying the same into effect, I wish it to be understood that I lay no claim
to any of the parts herein described, which may have been in use before the
date of my Patent; nor do I intend to confine myself to the precise arrange-
ment of parts herein shewn and described, as various alterations may be made
to suit circumstances, without departing from the nature of my Invention.
But what I claim as the Invention secured to me by the herein-before in part
recited Letters Patent is,-
First, evaporating ammoniacal liquor or gas water in close vessels, and
passing the vapours of such liquor through an acid solution so as to produce
the required salt.
And, secondly, in evaporating in close vessels the ordinary mixture of

page_text: ammoniacal liquor and acid, and condensing the vapours arising from such
evaporation by passing them through pipes or vessels kept cold by an external
application of cold water, as shewn and described in reference to Fig. 4, or by
any other convenient means, or by passing such vapours through a stream or
body of cold water, as above described.
In witness whereof, I, the said William Watson, have hereunto set my
hand and seal, this Thirteenth day of July, in the year of our Lord
One thousand eight hundred and forty-four.