Improvements in the Manufacture of Nitrate of Ammonium and of Resulting Bye-products.
Year: 1890

page_text: Date of Application, 10th Apr., 1890
Complete Specification Left, 10th Jan., 1891-Accepted, 21st Feb., 1891
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Nitrate of Ammonium and of
Resulting Bye-products.
I CHARLES ANTHONY BURGHARDT of 35 Fountain Street in the City of
Manchester Analytical Chemist do hereby declare the nature of this invention to
be as follows:-
My invention relates to the manufacture of ammonium nitrate and has for its
object to facilitate the production of such salt and to obtain useful bye-products
whereby the cost of production will be lessened. In a former invention for which
I made application for Letters Patent number 8841 of the year 1889 I produced
the said salt by means of a reaction between lead nitrate and ammonium sulphate,
lead sulphate being obtained as a bye-product.
My present invention consists of an improvement in such former invention.
In place of the ammonium sulphate 1 employ one of the carbonate salts of
ammonium. To avoid repetition I will herein mention only the ammonium car-
bonate salt. By the use of ammonium bi-carbonate I obtain lead carbonate as
a bye-product this salt being more valuable in its crude state and more readily
convertible into valuable lead compounds than the lead sulphate. I proceed in
the manner set forth in the Specification of my former invention substituting a
solution of ammonium bi-carbonate for the solution of ammonium sulphate. The
resulting lead carbonate precipitate is more insoluble in water than the lead
sulphate precipitate so that there is not the necessity for the exercise of the
same amount of care in the washing and treatment of the precipitate and also
the supernatant solution is left more free from lead so that if the operation be
properly effected with the use of a suitable proportion of the ammonium
bi-carbonate the resultant solution of ammonium nitrate will be quite or almost
entirely free from lead. In a variation of the process I treat the lead nitrate
When
solution with liquor ammonia or with dry ammonia or ammonia gas.
using liquor ammonia I add the liquor in equivalent proportion to the lead
nitrate solution. A white precipitate of hydrated lead oxide is thrown out and
ammonium nitrate remains in solution. When using dry ammonia I pass it into
the lead nitrate solution until all the lead is thrown out as hydrated lead oxide.
The reaction is complete when the smell of ammonia in the solution is perceptible
or when the solution has an alkaline reaction upon red litmus paper. The
ammonia will then be slightly in excess and all or nearly all of the lead will
have been thrown out in the precipitate. I run off the clear solution and heat
it until all the free ammonia has been driven off. I then add to the solution
ammonium bi-carbonate in quantity sufficient to precipitate any remaining traces
of lead. The lead carbonate which may be thrown out is allowed to subside
and the supernatant liquor should be a pure ammonium nitrate solution. The
solution obtained in accordance with my present invention may be concentrated
and treated in any suitable manner or as indicated in the Specification of my
said former invention. The lead oxide precipitate can be readily converted into
a valuable product suitable for use in the manufacture of paints or for other
purposes.
Date th
CA
DUTTON & FULTON,
1, St. James Square, Manchester, Agents

page_text: COMPLETE SPECIFICATION.
Improvements in the Manufacture of Nitrate of Ammonium and of
Resulting Bye-products.
I, CHARLES ANTHONY BURGHARDT, of 35, Fountain Street, in the City of
Manchester, County of Lancaster, Analytical Chemist, do hereby declare the nature
of this 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 :-
My invention relates to the manufacture of ammonium nitrate and has for its
object to facilitate the production of such salt and to obtain useful bye-products
whereby the cost of production will be lessened. In a former invention for which
I made application for Letters Patent number 8841 of the year 1889, I produced
the said salt by means of a re-action between lead nitrate and ammonium sulphate
lead sulphate being obtained as a bye-product.
My present invention consists of improvements in such former invention. In
place of the ammonium sulphate I employ one of the carbonate salts of ammonium.
By the use of ammonium bi-carbonate I obtain lead carbonate as a bye-product
this salt being more valuable in its crude state and more readily convertible into
valuable lead compounds than the lead sulphate. I proceed in the manner set
forth in the Specification of my former invention substituting a solution of ammonium
bi-carbonate for the solution of ammonium sulphate-that is to say-I dissolve in
separate vessels ammonium carbonate and lead nitrate avoiding the use of an excess.
of water. I then mix the two solutions and agitate until the re-action between the
two salts is complete the nitric acid leaving the lead and displacing the carbonic.
acid which was associated with the ammonium the carbonic acid uniting with the
lead and forming lead carbonate which is precipitated. For the production of
200 tons of ammonium nitrate about 405 tons of lead nitrate and 200 tons of
ammonium bi-carbonate would be required but in practice I prefer to test the
solutions so as to obtain the correct equivalent proportions as set forth in the
Specification of my said former invention. The resulting lead carbonate precipitate
is more insoluble in water than the lead sulphate precipitate so that there is not
the necessity for the exercise of the same amount of care in the washing and
treatment of the precipitate and also the supernatant solution is left more free from
lead so that if the operation be properly conducted with the use of a suitable
proportion of the ammonium bi-carbonate the resultant solution of ammonium
nitrate will be quite or almost entirely free from lead.
If preferred for any reason other carbonate salt of ammonium might be used
such for example as ammonium carbonate or ammonium sesqui-carbonate using the
proper equivalent proportions in each case. In a variation of the process I
treat the lead nitrate solution with liquor ammonia or with dry ammonia
or ammonia gas. When using liquor ammonia I add the liquor in equivalent
proportion to the lead nitrate solution. A white precipitate of hydrated lead
oxide is thrown out and ammonia nitrate remains in solution. When using
dry ammonia I pass it into the lead nitrate solution until all the lead is thrown out
as hydrated lead oxide. The reaction is complete when the smell of ammonia in
the solution is perceptible or when the solution has an alkaline reaction upon red
litmus paper. The ammonia will then be slightly in excess and all or nearly all of
the lead will have been thrown out in the precipitate. In practice I have obtained
the ammonia from ammonium sulphate using slaked lime to effect the
decomposition. I use a still heated by steam to effect the decomposition. I
dissolve the ammonium. sulphate in one tank and prepare the milk of lime in
another tank both tanks being in communication with the still so that the contents_
can be run off directly into the still.
The ammonia given off is passed first through a condenser to condense the
steam and then through a washer in order to intercept any lime or other
impurities which might be carried over from the still. The gas from the washer

page_text: is passed into water so as to produce ammonia solution or liquor. I dissolve lead
nitrate in a suitable quantity of water in a tank which can be run off into re-action
tanks on a lower level. When the solution is complete I run it off into one of the
said re-action tanks and ammonia solution is run in or supplied in sufficient
quantity to throw out all the lead from the lead nitrate solution. The lead is
precipitated as an oxide in the condition of a fine powder which is very suitable for
conversion into chrome yellows. It is advisable or necessary that the solution
shall be cold in order to avoid the formation of crystalline precipitate.
The contents of the tank are thoroughly agitated and run off on to a cloth filter
through which the clear liquid runs into a first filter tank the lead oxide remaining
on the filter. The oxide is washed with cold water several times until free from
salt or ammonia the, washings running into the tank below. The oxide is then
ready for conversion into chrome yellow or to be otherwise used as may be desired.
The liquor in the filter tank will contain a small proportion of lead oxide in
solution. To recover this I add a solution of ammonium carbonate until the
formation of a precipitate ceases. The liquid is then agitated and run off on to a
second filter the clear liquid passing into a second filter tank.
This liquid should be a pure solution of ammonium nitrate. I run off the solution
into evaporating pans and concentrate it to the crystallising point-that is to say
to about 67 degrees Twaddell. The solution is then transferred to crystallising
pans or cisterns and allowed to crystallise.
The crystals are placed in a hydro-extractor to free them from mother liquor and
are dried on drying plates or suitably treated to finish them for the market.
The operation can be varied by passing the ammonia gas from the washer
directly into the solution of lead nitrate until the re-action would be completed
but I prefer to use the ammonia as a water solution in the manner hereinbefore
described partly for the reason that I have obtained the lead oxide as a finer
powder and also for the reason that in the event of the liquor rushing back into
the still from any cause nothing but ammonia solution would pass into the still
whereas in the alternative procedure lead nitrate solution would pass into the still
and thus there would be loss of material. The proportions of materials required
I have found to be as follows namely:
-
Lead nitrate
Ammonium sulphate
Lime -
24 cwt.
11 cwt.
-
6 cwt.
Water about 50 gallons to each cwt. of lead nitrate.
I do not however confine myself to these proportions. I prefer to have two sets
of re-action and first filter tanks each set being supplied alternatively from the
tank in which the solution is prepared and delivering into the second filter tank so
that the two sets can be worked alternately but it will be evident that the plant
would be made to suit the quantity of the products which would be required to be
produced in each day. I do not confine myself to the obtainment of the ammonia
by re-action between ammonium sulphate and calcium oxide, as the ammonia might
be obtained directly from ordinary ammoniacal liquor or be otherwise obtained as
considered to be most convenient and economical. It is important that the nitrate
solution should not come into contact with iron therefore I use wood tanks and
earthenware taps the iron evaporating pans being enamelled but the still may be of
cast iron.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is :-
1. The production of ammonium nitrate by a re-action between lead nitrate and
one of the ammonium carbonates and the recovery as a bye-product of lead
carbonate.
2. The production of ammonium nitrate by the treatment of a solution of lead

page_text: nitrate with ammonia either in aqueous solution or in the form of ammoniacal gas
and the recovery of the resulting lead oxide.
3. The treatment of a solution of lead nitrate with ammonia as a vapour or
in solution until the lead is thrown out as oxide the treatment of the remaining
solution with ammonium carbonate to remove remaining traces of lead the concen-
tration and crystallisation of the clear solution of ammonium nitrate after removal
of the lead and the washing and recovery of the lead oxide for use in the preparation
of chrome yellows or for other uses substantially as set forth.
4. The process for the production of ammonium nitrate and of lead oxide
substantially as set forth.
Dated this 9th day of January 1801
>
DUTTON & FULTON,
1, St. James Square, Manchester, Agents.