AN IMPROVED MODE OF TREATING GUANO FOR THE PURPOSE OF OBTAINING CHEMICAL COMPOUNDS THEREFROM
Year: 1845

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILTON
GEORGE TURNER, of Gateshead, in the County of Durham, Doctor in
Philosophy, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Twenty-fourth day of December, in the ninth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Wilton George Turner, my exors, adiñors, and assigns, Her especial
license, full power, sole privilege and authority, that I, the said Wilton George
Turner, my exors, admors, and assigns, or such others as I, the said Wilton
George Turner, my exors, adññors, or assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during the term of
years therein expressed, should and lawfully might make, use, exercise, and
vend, within England and Wales and the Town of Berwick-upon-Tweed,
my Invention of "AN IMPROVED MODE OF TREATING GUANO FOR THE PURPOSE
OF OBTAINING CHEMICAL COMPOUNDS THEREFROM;" in which said Letters Patent
is contained a proviso obliging me, the said Wilton George Turner, 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 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
Wilton George Turner, do hereby declare that the nature of my said Inven-
tion consists in the improved mode of treating guano herein-after described, so as
to produce oxalic acid therefrom, without rendering it less applicable for the
production of certain other chemical compounds, for the manufacture of which
it has heretofore been used.
Now, the purposes to which guano has hitherto been applied in the manu-
facture of chemical compounds have been confined to the production of
ammonia and certain compounds of cyanogen. The principal, if not the only,
source of these substances in the guano is the uric, and which it contains, and
they have been derived from the uric acid either by the destructive distillation
of the guano, or by its combustion in fused potash. The object of my improved
mode of treating the guano is to obtain oxalic acid from it previously to its
being applied to the production of ammonia and compounds of cyanogen.
This I effect by acting on the uric acid of the guano with peroxide of lead or
manganese suspended in water at a boiling temperature, by which means it is
well known that it will be decomposed into oxalic acid, allantoin, and urea. The
former of these forms an insoluble compound with the lead or manganese, and
is thus separated from the allantoin and urea, and as the two last contain all
the nitrogen originally existing in the uric acid, this production of oxalic acid
is not attended with any loss of the nitrogen compounds; and in further com-
pliance with the said proviso, I, the said Wilton George Turner, now proceed
to describe my said improved mode of treating guano, or, in other words, the
manner in which my said Invention is to be performed.
In the first place, I must remark that the guano imported into this country may
be divided into two classes, the one containing the products of the urine of birds
in a perfect condition, the other (and this is by far the most common) charac-
terized by the presence of various products not originally existing in the urine,
but arising from after chemical changes. These classes of guano may readily be
distinguished by the action of cold water; if the guano belong to the first class
the solution thus formed, like all fresh urine, will have an acid reaction on test
paper, whereas it will have an alkaline reaction on test paper if it be of the
second class; and I would remark that this distinction of guano is essential, as
the methods of treating each must be slightly modified. Guano of the first
class, which has hitherto been imported only from Bolivia, should first be
reduced to powder by grinding or powdering, and steeped and well washed in
cold water. This will remove the soluble urine salts, consisting of sulphates
and muriates of soda and potash, and the superphosphates of lime. These
may be recovered by boiling to dryness, and will form valuable manures. The

page_text: insoluble residue remaining after the washing should now be digested in a
strong but cold solution of carbonate of soda or potash. This is to free the
guano as much as possible from coloring matter. [Note, the alkali, of
course, may be afterwards purified by exposure to a red heat, for the purpose
of being used again.] The insoluble residue now consists of urate of ammonia
and bone earth, and may be at once treated with dilute sulphuric acid, which
will liberate the uric acid, and bring it into a fit condition to be acted on by
peroxide of lead. The only guide required for the quantity of the acid is
that it should remain to the last a little in excess beyond what is required to
neutralize the ammonia. I prefer, however, although adding slightly to the
expence, the following process, that is to say, to boil the residue in a dilute
solution of soda or its carbonate, by which I obtain a solution of urate of soda;
care should be taken that a large excess of soda be not used in this process,
although it is equally important to have enough to decompose the whole of the
urate of ammonia of the guano. As a guide, one hundred and sixty-eight
pounds of uric acid will require thirty-one pounds of soda; the operation like-
wise would be more economically conducted in a still, as it would enable the
operator to collect the ammonia that passes off; the still should be large, as the
evolution of ammonia occasions a great deal of frothing. The urate of soda is
only sparingly soluble in cold water; the solution must, therefore, be separated
from the earthy residue as hot as possible, and the latter carefully washed with
boiling water till freed of utrate of soda. The weak solutions may be kept to
use in the next operation. The strong solutions, however, which on cooling
would deposit urate of soda, are to be treated with a second quantity of
carbonate of soda, equal in amount to the first, and then evaporated till a
deposit is observed. On cooling, the whole forms a confused crystalline mass,
from which the liquor must be drained and pressed, and the solid residuum
washed with cold water. In this way I have succeeded in obtaining urate of
soda of a pale straw colour, even from guano of the second class of a very dark
colour, and this is a point of great importance, as influencing the color of the
oxalic acid produced. As some guanos, however, are much more colored
than others, it may sometimes be found that the uric acid is still of too
dark a colour. In this case it is advisable to boil the urate of soda again
in a strong solution of carbonate of soda. This process will dissolve the
coloring matter without taking up much of the urate, and this little is not
lost, as the carbonate of soda used for purifying one batch should be used for
dissolving the uric acid out of the guano of the next batch. The urate of
soda is now added to a boiling solution of sulphuric or muriatic acid, in such
excess as to insure a perfect separation of the soda, and the ebullition should

page_text: .
be maintained for a quarter of an hour. The uric acid thus obtained, after
being carefully washed with cold water to free it from all adhering acid, is
next to be boiled with pure peroxide of lead. This is more expensive than
peroxide of manganese, but it effects the changes on the uric acid with
facility, while the peroxide of manganese is slow and tedious in its action,
though either will do for the purpose. The process of boiling with peroxide.
of lead, supposing that to be the substance selected, should be conducted in
the following manner:-A known weight of the uric acid should be placed in
an open cylindrical iron vessel capable of holding two gallons of water for
every pound of the acid and fitted to boil by steam; the water is then added,
but I prefer to use a clear saturated solution of lime water, and as soon as it
is heated and in brisk ebullition the peroxide of lead, which is of a dark puce
color, should be added in successive portions as long as it is observed to be
whitened by the boiling liquid. If the materials be quite pure one hundred
and sixty-eight pounds of uric acid will whiten two hundred and forty pounds
of peroxide of lead, and in practice the above number will serve as a close
guide. It is essential here to be extremely careful not to use an excess of the
peroxide of lead for reasons hereafter to be explained; when therefore the
quantity of peroxide of lead approaches near the maximum that can be
whitened, which, as above stated, is two hundred and forty pounds to one
hundred and sixty-eight of uric acid, it should be added with great caution
so as to make the excess as small as possible, and this slight excess should
then be removed by the addition of a small quantity of uric acid, just sufficient
for that purpose. The whitish powder thus obtained is oxalate of lead. The
supernatent liquor should then be drawn off, and residuum washed with clean
water. When the residuum is thus clean it should be put into a leaden vessel
and boiled with muriatic acid diluted with about its own weight of water.;
two hundred pounds of acid of sp. gr. 1-179 should be used for every two
hundred and forty pounds of peroxide of lead which has been converted into
oxalate of lead. The last mentioned liquid now contains oxalic acid, which
is readily obtained in its solid form by evaporation and crystallization, but it
should be first treated with dilute sulphuric acid, added in small quantities as
long as a precipitate is formed. The insoluble part is now muriate of lead,
and should be collected, after carefully washing it, to be reconverted into
peroxide of lead by processes explained hereafter. I have already stated that
the water in which the uric acid has been boiled with peroxide of lead
holds two substances, known by the names of allantoin and urea, in solution.
By heating and thus evaporating until a pellicle is observed to form on the
surface of this water, the greater portion of the allantoin is deposited in

page_text: crystals as the liquor cools; the rest is obtained by the further evaporation of
the mother liquor, which at length forms a thick syrup consisting of urea.
The allantoin should be introduced into a still with a solution of any caustic
alkali or alkaline earth, such as lime suspended in water or a solution of baryta.
By boiling, the allantoin is decomposed by the action of the caustic alkali into
oxalic acid and ammonia; the former unites with the alkali used, while the
ammonia passes over and may be collected as liquor ammonice. The oxalic
acid thus generated may be obtained as oxalate of potash if potash had been
the alkali used, or as oxalic acid if baryta had been employed by decomposing
the latter oxalate by means of sulphuric acid. Fifty pounds of oil of vitriol are
required to decompose one hundred and twenty-two pounds of oxalate of
baryta, and the process conducted as before described for oxalate of lead.
[Note, as a general guide for the treatment of the allantoine, I should say that
seventy-nine pounds of allantoine will require one hundred pounds of caustic
potash for its decomposition, or the chemical equivalent of the other alkalies which
have been named.] The urea, which has been brought to the consistence of a
syrup, may be used either for the manufacture of ammonia or of compounds
of cyanogen, or partly applied to both purposes. Ammonia is obtained by
boiling it with milk of lime in a still, when it is decomposed into carbonic
acid which unites with the lime, and into ammonia which passes into the
receiver. If required for the purpose of compounds of cyanogen, it should be
brought to perfect dryness on a water bath, and mixed with coal tar or other
carbonatious bodies, being treated as guano in processes now well known, or the
dry urca may be exposed to a heat of two hundred and fifty in a retort. At this
heat it fuses, boils, and is decomposed into ammonia, which passes off, and
may be condensed by a suitable apparatus and into cyanuric acid, which remains
as a solid in the retort. This latter may readily be converted into cyanide of
potassium, being added to fused carbonate of potash charged with carbonaceous
matter, and thus be converted into ferrocyanide of potassium by processes
well known. To ensure the success of the processes for converting uric acid
into allontoine, oxalic acid, and urea, extreme attention must be paid to three
points; first, that the uric acid be perfectly free from any adhering sulphuric or
muriatic acid; secondly, that the peroxide of lead be also perfectly free either from
acid or chlorine, and be used in the state of an impalpable powder; and, thirdly,
that no excess of the peroxide be used. The failure which results from the neglect
of any of these precautions arises from the same chemical cause, namely, the
facility with which free oxalic acid and peroxide of lead react on each other,
producing carbonic acid and carbonate of lead; hence if any sulphuric or

page_text: muriatic acid be adhering to either the uric acid or the peroxide of lead, they set
free the oxalic acid, which is instantly destroyed; this change is at once indicated
by the rapid evolution of carbonic acid. If an excess of peroxide of lead had
been used, the saine thing occurs; when the oxalate of lead is decomposed,
or if the peroxide of lead be not used in the finest powder, the exterior only
of any small fragments are acted on by the uric acid. This may readily be seen
by boiling a few fragments of peroxide of lead in uric acid; they become
coated with oxalate of lead, which protects the interior; for, however long the
process is continued, the heart of each fragment, when broken, will show the
dark pure colour. To insure the necessary freedom from acid in the case of
uric acid, I prefer to decompose the urate of soda by muriatic acid, and then
expose the uric acid to a steam heat till perfectly dry. It is advisable,
however, that the manufacturer should prepare a certain portion of pure
uric acid and peroxide of lead as standards, by which to test cach batch
of uric acid and peroxide of lead before he uses them in the large scale, as
any carelessness might otherwise occasion most serious losses.
I prefer
the use of the first class guano, but when that cannot be obtained I take
the best samples of the second class I can obtain, selecting of course those
which are richest in uric acid; they are obtained abundantly from Chiucha,
containing from 16 to 20 % of uric acid, and these may be very advantageously
employed. I have before stated that this second class guano contains several
substances resulting from after chemical changes; the principal of these are
carbonate of ammonia and oxalic acid, which have evidently been' produced by
the slow oxidation of the uric acid; they also contain a large quantity of
humus, and are of a much darker color than the perfect guano.
Modifications of the before described process have been adopted to obtain
this ready formed oxalic acid. The latter exists in the guano, partly in com-
bination with ammonia, and partly in combination with lime. The oxalate
of ammonia is of course taken up by the cold water, in which the guano
is first digested, and may be precipitated from the urine salts by any salt of
lime or baryta, the cheapest of which is the sulphuret of barium; and from
the oxalate of baryta the oxalic acid may be obtained by decomposing with
sulphuric acid. I have found, however, that the oxalic acid thus produced
is of a very dark color. I therefore prefer to digest the guano in a cold
and weak solution of chloride of calcium, by which the whole of the
oxalic acid is left with the insoluble portion of the guano as oxalate of lime.
This insoluble portion is now boiled as before described in a dilute solution
of carbonate of soda; this not only forms urate of soda, but also oxalate of

page_text: soda. I now allow the whole to cool before drawing off the liquor, by which
the most of the urate of soda is deposited. The solution is now evaporated,
when first urate of soda, and then oxalate of soda, which is also a sparingly
soluble salt, is deposited, and the oxalate of soda thus obtained rendered
colorless by washing with a cold solution of carbonate of soda and subsequent
crystallization. Pure oxalic acid may then be obtained from it by precipitating
the oxalic acid by means of sulphuret of barium, and then decomposing by
sulphuric acid as before described. The urate of soda must of course be treated.
as before described; and I may here remark, that the principle I have adopted
to obtain oxalic acid in a pure state from guano depends on the solubility of
the coloring matter of the guano in the carbonate of soda.
I have now to describe the process by which I convert the muriate or sulphate.
of lead back into peroxide, so as to bring it back into a fit condition to be again
used for the conversion of uric acid into oxalic acid. I will suppose that I
have muriate of lead containing a little sulphate, having used first muriate acid
and then a little sulphuric acid to complete the decomposition of the oxalate of
lead. The apparatus required will be an ordinary chlorine still, attached to a
Woulfe's apparatus, consisting of at least two vessels, cach capable of holding
20 lbs. of water to every pound of muriate of lead, to be operated on and fitted
with what is called a rouser or stirring apparatus. Each vessel is now charged
with a carefully prepared milk of lime, containing one part of lime to forty of
water; and with the muriate of lead to be acted on, we shall thus have one.
part of lime to two of muriate of lead; and though this is more lime than is
necessary, the excess is advantageous without occasioning any loss of material.
The apparatus being thus arranged, the chlorine still is charged, and the chlorine
gas generated, passing into the Woulffe's vessel, is readily absorbed by the
milk of lime and muriate of lead, which, however, should be kept from settling.
to the bottom of the vessel by the rouser. The generation of chlorine should
be continued until it is found to pass through the first Woulfe's vessel without
further absorption. This indicates that the changes are complete in that vessel;
the whole contents should therefore be removed, and be replaced by a new
charge of muriate of lead and milk of lime. The chlorine may now be again
generated, but the stream of gas should be made to pass first into the second
Woulffe's vessel, and thus the two are worked off alternately. In this way the
muriate of lead is converted into peroxide, while the milk of lime is now a
solution of chloride of calcium, of chloride of lime (or bleaching powder), and
of chlorine. This solution of bleaching liquor is withdrawn from the peroxide
of lead and treated with muriate of lead till it loses its smell of chlorine; it

page_text: acts like the chlorine gas itself in converting muriate of lead into peroxide,
and therefore assists the change which is afterwards to be completed in the
Woulffe's apparatus. The peroxide of lead which is there produced should be
washed repeatedly with boiling water till it becomes tasteless; it should then
be boiled in a very dilute solution of soda, and again washed until tasteless.
It is now in a fit condition for use, and should be kept covered with water to
preserve its impalpable state. To obtain a supply of peroxide in the first
instance, any of the known methods may be adopted. I believe, however, it
will be most economical to use the brown acetate of lead, treating it first with
chlorine in Woulffe's apparatus, by which the acetic acid is liberated and
the lead converted into a mixture of peroxide and chloride of lead, and the
change completed by milk of lime and chlorine.
Now, whereas it is evident that various modifications of the various processes
herein-before described may be adopted, and also that many of the processes
have been introduced and described merely to enable the manufacturer by
economising his materials to avail himself to the fullest extent of the benefit of
my said Invention, and form no part of my claim to invention; but what I
claim as my Invention is, the improved mode of treating guano by boiling
the uric acid obtained from it with peroxide of lead or peroxide of manganese
in water or lime water, and thus producing oxalate of lead, allantoine, and urea;
whereby I have been enabled, by the after processes herein-before described,
to manufacture oxalic acid from guano without losing the nitrogen compounds
hitherto obtained from it; and such my Invention being to the best of my
knowledge and belief entirely new, and never before used in that part of Her
Majesty's United Kingdom of Great Britain and Ireland called England, Her
Dominion of Wales, and Town of Berwick-upon-Tweed, I do hereby declare
this to be my Specification of the said Invention.
In witness whereof, I, the said Wilton George Turner, have hereunto set
my hand and seal, this Fourth day of June, One thousand eight
hundred and forty-six.

page_text: AND BE IT REMEMBERED, that on the Fourth day of June, in the
year of our Lord 1846, the aforesaid Wilton George Turner came before our
said Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according to
the tenor of the Statute made for that purpose.
Enrolled the Fourth day of June, in the year of our Lord One thousand
eight hundred and forty-six.