IMPROVEMENTS IN THE MANUFACTURE OF ALKALINE SALTS
Year: 1857

page_text: LETTERS PATENT to Thomas Bell, of Plaistow, in the County. of Ess
for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF ALKALINE
SALTS."
Scaled the 8th January 1858, and dated the 13th October 1857.
PROVISIONAL SPECIFICATION left by the said Thomas Bell at the Office
of the Commissioners of Patents, with his Petition, on the 13th October
1857.
1,
I, THOMAS BELL, of Plaistow, in the County of Essex, do hereby declare
the nature of the Invention for "IMPROVEMENTS IN THE MANUFACTURE OF
ALKALINE SALTS," to be as follows:-
This Invention has for its object improvements in the manufacture of
alkaline salts. For this purpose I place old or refuse leather in a retort, and
submit it to destructive distillation, and receive the volatile products in vessels
containing sulphuric or hydrochloric acid until the acid is saturated; afterwards
the liquid is removed from the vessels and evaporated, so as to cause the sul-
phate or muriate of ammonia to crystallize.
The volatile products resulting from the destructive distillation of bones
may be applied in the same way for the manufacture of salts of ammonia.
In place of receiving the volatile product resulting from the destructive dis-
tillation of leather and bones in acid, as above described, the products of such
distillation of these or other animal matters may be caused to pass directly
into a solution of sulphate or muriate of soda or potash, and then a sulphate
or muriate of ammonia is obtained as in the former case, and also a carbonate
of soda or potash.

page_text: Salts of ammonia may also be obtained from a material which is used in
the purification of coal gas. This material consists of oxide of iron mixed
with other substances, and it is used over and over again at the gasworks
until it becomes so saturated with sulphur and ammonia as to be unfit for
further use. In order to obtain the ammonia from this refuse material, I
distil it, and receive the volatile products in vessels containing sulphuric or
muriatic acid. By this process also the sulphur is separated, and comes over
with the ammonia; after a time it settles to the bottom of the. solution of the
salt, and when it has been dried it is suitable for use in, the manufacture of
sulphuric acid.
In concentrating solutions of salts of ammonia, in order to economize fuel,
and to avoid loss of ammonia. I employ a pan having a series of tubular flues
passing through it, and furnished with a close cover, and in connection with
the pan are air pumps or other apparatus to maintain a vacuum in the pan.
during the process of evaporation..
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Bell in the Great Seal Patent Office on the 13th
April 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
BELL, of Plaistow, in the County of Essex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of October, in the year of our Lord
One thousand eight hundred and fifty-seven, in the twenty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Thomas Bell, Her special licence, that I, the said Thomas Bell, my
executors, administrators, and assigns, or such others as I, the said Thomas
Bell, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during the
terin 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 MANU-
FACTURE OF ALKALINE SALTS," upon the condition (amongst others) that I, the
said Thomas Bell, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, 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

page_text: said Letters Patent.
NOW KNOW YE, that I, the said Thomas Bell, 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
thereof, that is to say:-
This Invention has for its object improvements in the manufacture of
alkaline salts. For this purpose I place old or refuse leather in a retort, and.
submit it to destructive distillation, and receive the volatile products in vessels
containing sulphuric or hydrochloric acid until the acid is saturated; afterwards
the liquid is removed from the vessels and evaporated, so as to cause the sul-
phate or muriate of ammonia to crystallize.
The volatile products resulting from the destructive distillation of bones
may be applied in the same way for the manufacture of salts of ammonia.
In carrying out this portion of my Invention, I place old or refuse leather or
bones in an iron retort, such as that usually employed in gas making, which
is heated by a furnace in the usual way to a low red heat, and the gases and
vapors from the retort pass into a coil of pipes. This coil is constructed of
a series of four-inch pipes about eight feet long each, and connected together
at the top and bottom by semicircular bends; in this coil the gases and vapors
cool, and the tar condenses and is drawn off at the lower part of each of the
convolutions of the coil. The gases and vapors are conducted from the coil
into a vessel containing sulphuric or hydrochloric acid of commercial strength
mixed with an equal volume of water, and the pipe which leads the gases and
vapours into the vessel dips below the surface of the acid, so that the gases
and vapors are compelled to bubble through it in escaping. The vessel con-
taining the acid is closed at the top, and a pipe passes from it to a second
similar vessel also containing acid, through which the gases and vapours pass
as before, and from this vessel to a third, and so on.
vessels which I prefer ordinarily to employ is five or six.
The number of acid
When the acid in
and fresh acid is
the first of these vessels becomes saturated, it is run out
introduced, and then the vessels are coupled up, so that the vessel containing
the fresh acid becomes the last of the series. The saturated acid run out
of the vessels is concentrated to the "salting" point, and crystallized as is
usual when treating solutions of sulphate and muriate of ammonia, and the
incondensible gas which escapes from the last acid vessel is led away to a
furnace, where it is set free under the fire bars, so that it may be consumed
and the creation of a nuisance avoided.
In place of receiving the volatile products resulting from the destructive dis-

page_text: tillation of leather and bones in acid, as above described, the products of such
distillation of these or other animal. matters may be caused to pass directly
into a solution of sulphate or muriate of soda or potashi, and then a sulphate
or muriate of ammonia is obtained as in the former case, and also a carbonate
of soda or potash.
In manufacturing carbonate of soda or potash in this manner, I employ
apparatus similar to that already described, only in the place of the acid I
substitute a solution of sulphate or muriate of soda.or potash containing one
part, by weight, of the salt to three parts water, by which I obtain a pre-
cipitate of bicarbonate of soda or potash, and when no further decomposition
of the sulphate or muriate takes place, I run out the liquid into a settling
vessel where the bicarbonate deposits; I then separate the deposit and put
it into bags of thick fabric and press it dry, afterwards it may be roasted
to convert it into the neutral carbonate. The clear liquid drawn off from the
precipitate is evaporated to the proper strength for crystallizing out the
sulphate or muriate of ammonia, and the mother liquor separated from these
crystals, and which contains principally sulphate or muriate of potash or soda,
is returned to the decompositing vessel; in this manner the mother liquors
are worked back and back until they become too foul to be any longer
profitably employed; they are then evaporated to dryness, and the residue is
sold as a manure or treated to separate the salt from the impurities.
bones are distilled in the manner above described, the residue left in the
retorts at the termination of the process is animal charcoal, suitable for the
use of sugar refiners.
་
When
Salts of ammonia may also be obtained from a material which is used in
the purification of coal gas. This material consists of oxide of iron mixed
with other substances, and it is used over and over again at the gasworks
until it becomes so saturated with sulphur and ammonia as to be unfit for
further use. In order to obtain the ammonia from this refuse material, I
distil it, and receive the volatile products in vessels containing sulphuric or
muriatic acid. By this process also the sulphur is separated, and comes over
with the ammonia; after a time it settles to the bottom of the solution of the
salt, and when it has been dried it is suitable for use in the manufacture of
sulphuric acid. In carrying out this part of my Invention, I place the oxide
of iron as it is obtained from the gasworks into a retort similar to that used
in gas making, and heated in a similar manner. The vapours pass away
directly to a vessel containing commercial sulphuric or muriatic acid, but the
pipe introducing the vapors to this vessel does not dip into the acid, otherwise
it might become choked with the condensed sulphur, and the vessel is so
:

page_text: constructed as to expose a large surface of acid, so that all the sulphur may
be condensed in this vessel: The vapors afterwards pass to other vessels
similar to. those used in the process, already described, when leather or bones
are distilled, and the process is worked in a similar manner. The deposited
sulphur is removed from the first vessel from time to time, and the acid in
this vessel is changed as soon as it becomes saturated.
In concentrating solutions of salts of ammonia, in order to economize fuel,
and to avoid loss of ammonia, I employ a pan having a series of tubular fines
passing through it, and furnished with a close cover, and in connection with
the pan are air pumps or other apparatus to maintain a vacuum in the pan
during the process of evaporation. The pan which I prefer to employ is of
sheet iron and rectangular in foran; it is about 20 feet long, 5 or 6 feet wide,
and 2 feet deep, except at one end over the furnace, where it is only one foot
deep. The furnace extends from side to side of the pan and is 3 feet in
length; its fire bars are on a level with the bottom of the pan, and over it a
flat fire brick arch is turned to protect the pan where the flames would other-
wise play directly on it. From the end of the furnace six 6-inch tubular flues
proceed horizontally to the further end of the pan, and afterwards the flues
(formed in setting the pan) return under the bottom of the pan and then
enter the chimney. The pan is covered with an arched cover of sheet iron
fixed to it by screw bolts, so that it may be occasionally removed if necessary,
and a vacuum is maintained in the pan when at work by air pumps worked by
a steam engine, as is commonly practised when evaporating solutions of sugar.
The solution is run out of the pan where it is concentrated to the crystallizing
or salting point, care being taken to avoid carrying the evaporation beyond
this point, otherwise an injurious deposit might take place in the pan. When
economy of first cost is of primary importance, the pan may be worked without
vacuum and the cover and air pumps dispensed with.
In witness whereof, I, the said Thomas Bell, have hereunto set my hand
and seal, this Twelfth day of April, in the year of our Lord One
thousand eight hundred and fifty-eight.
Witness,
S. CARPMAEL.
THOMAS BELL. (L.S.)