CERTAIN IMPROVED MODES OR MEANS OP PRODUCING OR OBTAINING AMMONIACAL SALTS
Year: 1852

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
11UNT, of Stoke Prior, in the County of Worcester, 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 Thirtieth day of September, in the sixteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said William Hunt, Her especial license, full power, sole privilege and
authority, that I, the said William Hunt, my exors, adññiors, and assigns,
and such others as I, the said William Hunt,. my exors, adiñors, 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 "CERTAIN IMPROVED MODES OR MEANS
OP PRODUCING OR OBTAINING AMMONIACAL SALTS;" in which said Letters Patent
is contained a proviso, obliging me, the said William Hunt, 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 inrolled in Her Majesty's High Court of
Chancery within six caleudar 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 Hunt, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, is 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):-
The first part of my Invention of improvements in the means of producing
or obtaining ammoniacal salts relates to an improved method of obtaining
sulphate of ammonia from the ammoniacal liquors produced during the manu-
facture of coal gas. This object is effected by bringing these alkaline or
ammoniacal liquors into contact with sulphurous acid gas by causing them to
percolate through a bed of pebbles, coke, or other hard substances, upon which
such liquors would have no action, and during the operation which takes place
in an apparatus herein-after described, a stream of sulphurous acid gas is
made to pass through the bed of pebbles or coke, and when the sulphurous
acid gas comes in contact with the ammonia, it combines therewith, and
produces the chemical compound known as sulphite of ammonia, which, by
exposure to the atmosphere in the course of slow evaporation, or otherwise, is
made to absorb oxygen, and thereby become converted into a sulphate of
ammonia. I find it convenient to obtain the sulphurous acid gas by burning
off the sulphur from common coaly or other pyrites, and the gas'so obtained
is to be partially cooled (by passing under a pan' containing water or other
fluid) before it enters the condenser or apparatus in which it is to be brought
into contact with the ammonia. In cases where the ammoniacal liquors can
be obtained near to' vitriol works, I prefer using the spare gases which are
usually allowed to escape from the vitriol chamber, instead of generating gas
on purpose. The gases obtained from vitriol chambers consist of sulphuric
acid, sulphurous acid, and nitrous acid, and 'they may be applied in the same
way as that already described for sulphurous acid, for fixing the ammonia and
making salts of ammonia. In carrying on the combining operation, it will be
advisable to employ an excess of sulphurous acid in the condenser or combining
apparatus, so as to cause the ammoniacal liquor to be 'charged with an excess
of acid, which excess may be afterwards neutralized by the addition of unsul-
phated liquor. The presence of the excess of acid or ammoniacal liquor may
be detected by a slip of litmus paper, which will be reddened by acid; or of
turmeric paper, which will be made' brown by the 'unsaturated ammoniacal
liquor or uncombined alkali.
I
In order that tlic nature and object of this part of my improvements may
be more clearly understood, I have in the accompanying Drawings shown at

page_text: Fig. 1 a vertical section of an apparatus for bringing the sulphurous acid into
contact with the ammonia contained in ammoniacal gas liquor, and causing
the two chemical agents to combine and form neutral salts. a, a, is a tower
which I denominate the condenser, and which may be constructed of stone or
brickwork, but which in this instance is shewn as constructed of timber and
lined with lead. This tower is to be about one-third filled with pebbles or
broken stone, and the remaining portion with coke. The height and dimen-
sions of the tower or condenser must of course depend upon the quantity of
work intended or required to be done. Upon the top of this tower is placed a
reservoir or cistern b, b, to contain the ammoniacal liquors or whatever liquid
may be required to percolate through the mass of coke and broken stone in
the tower beneath. Immediately below the reservoir or cistern b, b, is placed
a small vessel or chamber c, which is furnished with a tumbling box d, into
which the liquor from the cistern is allowed to run from a pipe e. The
tumbling box d being mounted on centres will (when it has received a certain
quantity of liquid) turn over and discharge the same into the vessel c, from
whence it will run on to and be distributed over the coke and pebbles in the
tower. The sulphurous acid gas is generated by burning pyrites or other
substances containing sulphur in the grate e, e; the gas evolved passes off
by the flue f, and is conducted to the tower or condenser. In order to cool the
gases before they enter the tower they are made to pass under a pan or
chamber g, containing cold water; or, instead of this water chamber g,
evaporating pans containing a saturated solution of the neutral salts may be
placed on the flue, and, by abstracting the heat from the gases, will cool the
same, and the solutions will be slowly evaporated. The gases being thus
cooled, are then conducted to the upper part of the tower, where they are
brought into contact with the ammoniacal liquor which is trickling down
through the coke, and which will in its passage take up a dose of the acid gas,
If
and will ultimately fall into a lead or other pan or receiver h at bottom.
preferred, the sulphurous acid gas may be admitted at the bottom of the tower,
and drawn upwards by a flue or chimney with a strong draught, which will
draw or carry off all the uncondensed or uncombined vapours; these, if
thought desirable, may be again passed through the same or a similar
apparatus, in order that all the acid gas or other valuable products may be
taken up.
Fig. 2 is a vertical section of a modification of the apparatus just described,
the principal difference in construction being that the acid gases are admitted
to the apparatus at the bottom, and the uncondensed and uncombined gases
are drawn off from the top or upper part.

page_text: The sulphited ammoniacal liquor prepared by the above process must be
afterwards transferred to lead or iron pans, in order to evaporate therefrom
the aqueous particles. For evaporating these solutions I prefer to use iron
pans, and the process should be carried on at a low temperature, not higher
than two hundred degrees of Fahrenheit. This slow evaporation promotes the
oxydation of the sulphite, and its conversion into sulphate will be found to
proceed rapidly during the evaporating operation. The spare heat from the
gas retorts, or from the heating chamber or flues in which the sulphurous gas
is generated, may be advantageously employed for the evaporating process, as
an economy of fuel is thereby effected. It will also be found that the tem-
perature is more regular than would be obtained by placing an evaporating
pan directly over a naked fire. The evaporation of the salts may be carried
on in several pans simultaneously; the size or number of these pans must of
course depend upon the quantity of liquor to be evaporated; but I would here
remark, that the evaporation in some of the pans should be carried on until the
liquor is concentrated or begins to crystallize at the bottom of the pan, it
should then be removed to a pan where it may be dried and reduced to a salt.
This latter pan I call the salting pan, the others I call evaporating pans.
A portable cover is placed over the evaporating pans, and may be connected
with a flue or pipo leading to a small condenser filled with coke; and, upon
causing this condenser to communicate with a chimney draft, the steam and
any sulphite of ammonia in a gaseous state, and that may have escaped oxyda-
tion when driving off the last portions of water, will be drawn off, and the
sulphite will be condensed in the condenser, and may be run back to the
evaporating pans, where it will be re-exposed and evaporated with fresh
liquors. The salts, when drying in the drying pan, should be constantly
stirred, to prevent them from adhering to the pan, and when dry they may be
taken out and packed in casks, or laid aside as an article suitable for
manure or for other purposes to which sulphate of ammonia is or may be
applicable.
Having now described my improvements, and the best means with which I
am at present acquainted for carrying the same into effect, I would' observe in
conclusion, that I do not mean or intend to confine myself rigidly to the precise
arrangement or construction of apparatus whereby the combination of the
chemical products is effected, as they may doubtless be varied without
departing from the nature and object of my said improvements. But that
which I consider to be new, and therefore wish to claim as the Invention
secured to me by Letters Patent, is the apparatus above described, or any
mere modification thereof, in which sulphurous acid gas is made to combine

page_text: with ammonia, cither in a gaseous state, or when contained in the ammoniacal
liquors obtained from gas works, by causing the acid gas and the ammonia or
ammoniacal liquors to percolate through a condenser or chamber containing a
mass of broken material such as coke, pebbles, stones, or other substances
which are not liable to be acted on by the chemical agents, and whereby the
acid gas and ammonia are brought into intimate contact.
I also claim the use and application, as above described, of the waste
gases obtained from the vitriol chambers during the manufacture of sulphuric
acid.
In witness whereof, I, the said William Hunt, have hereunto set my
hand and seal, this Thirtieth day of March, in the year of our Lord
One thousand eight hundred and fifty-three.
Enrolled the Thirtieth day of March, in the year of our Lord One
thousand eight hundred and fifty-three.