IMPROVEMENTS IN THE MANUFACTURE OF SODA AND POTASH
Year: 1846

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANCOIS
STANISLAS MELDON DE SUSSEX, of Millwall, in the County of Middlesex,
Manufacturing Chemist, send giceting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent under the Great Seal of the United Kingdom of Great Britain and
Ireland, bearing date at Westminster, the Twenty-ninth day of June, in the
tenth year of Her reign, did give and grant unto me, the said Francois
Stanislas Meldon de Sussex, my cãors, admors, and assigns, Her special
licence, full power, sole privilege and authority, that I, the said Francois
Stanislas Meldon de Sussex, my exors, adiñors, and assigns, and such others
as I, the said Francois Stanislas Meldon de Sussex, my exors, adñors, 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 mentioned, should
and lawfully might make, use, exercise, and vend, within that part of the
United Kingdom of Great Britain and Ireland called England, Her Dominion
of Wales, and Town of Berwick-upon-Tweed, and also in the Islands of Jersey,
Guernsey, Alderney, Sark, and Man, and in all Her Colonios and Plantations
abroad, my Invention of "IMPROVEMENTS IN THE MANUFACTURE OF SODA AND
POTASH," in which said Letters Patent there is contained a proviso requiring
that I, the said Francois Stanislas Meldon de Sussex shall particularly
describe and ascertain the nature of my said Invention, and in what manner
the same is to be performed, by an instrument in writing under my hand and
seal, and cause the same to be inrolled in Her said Majesty's High Court of
Chancery within six calendar months next and immediately after the date

page_text: of the said in part recited Letters Patent, as, reference being thereunto had,
will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Francois Stanislas Meldon de Sussex, do hereby declare that the nature of
my Invention, and the manner in which the same is to be performed, are t
particularly described and ascertained in and by this present Instrument in
writing, as follows, that is to say.
My said Invention consists of a new mode or modes of obtaining soda and
And in order to
potash from the several salts which contain those alkalies
make the description of my said Invention more easily understood, I must first
state, that I have found that the aflinities of these alkalies respectively for
other substances vary according to the temperaturo at which those alkalies
respectively (or the salts containing them) are brought into contact with such
other substances.
My said Invention consists,-
Firstly, of a mode of obtaining nitrade of soda or potash (to be afterwards
decomposed, as herein-after mentioned) from the ordinary chlorides of sodium
or potassium, called also muriate of soda and potash, by subjecting those salts
to the action of hydrated nitric acid, at a heat of about 212° of Fahrenheat,
as herein-after described; and
Secondly, of a mode of obtaining soda or potash from a nitrate or muriate
of those alkalies respectively, by subjecting such nitrate or muriate to the
chemical action of one or more of the substances commonly called earth, at a
red heat, so as to decompose it, as herein-after also described.
And firstly, for the purpose of performing the first part of my said Inven-
tion, I employ a pan or vessel of any convenient size or shape, and made of
earthenware (or any other material which is not liable to be chemically acted
upon by the substances to be placed in it), and having a cover of a similar
material fitted air-tight, but with two apertures therein; one for the insertion
of a funnel, by means of which acid may be introduced into the pan or vessel,
and the other aperture for the insertion therein of a pipe or tube, which is to
be connected with any convenient chamber or receiver in which the gaseous
products evolved from the pan or vessel may be condensed. The funnel or
pipe must also be made of such materials as are not liable to be chemically
acted upon by the substances which will come in contact with them. The
pan or vessel which is used for the purpose of performing this part of ny
Invention must be heated by means of steam, an oil or tallow bath, or any
other convenient means by which the pan or vessel may be heated to the
degree of about 212° of Fahrenheat. In the pan or vessel such as I have

page_text: described I place sixty parts of chlonde of sodium, and then add to it such a
quantity of nitric acid as, according to the strength of the acid used, will be
equivalent to fifty-four parts of pure nitric acil The pan being covered and
made air-tight, and, by means of the pipe or tube before mentioned, being
made to communicate with such a chamber or receiver as aforesaid, heat is to
be immediately applied to the vessel, and the application of heat mast be con-
tinued, so that the contents of it may be kept at the heat before mentioned
until the process is complete. In the course of about twelve hours the whole
or nearly the whole of the chloride of sodium will be decomposed, and the
hydrochloric acid, which will be evolved, may be condensed in such cham-
ber or receiver as aforesaid in any of the modes known or usually adopted
for that purpose
This part of the process will be known to be completed
when the action of the heat upon the contents of the pan or vessel ceases to
produce any further gascous products I have generally found that the pro-
cess already described is sufficient for the decomposition of the chloride of
sodium and the production of the nitrate of soda, but if it should be found
that, in consequence of any imperfection in the mode of performing the pro-
cess or otherwise, than the whole of the chloride of sodium has not been
decomposed, and that a portion of the nitric acid has been distilled or driven
over into the condensing receiver, it will be found advantageous to return the
liquid produce of the distillation back into the pan or vessel before mentioned,
so that the portion of nitric acid which it contains may be united with the
base of the undecomposed chloride of sodium, and the bydrochloric acid must
then again be distilled or diven off, as before, and if, in consequence of any
such imperfection as aforesaid or other wise, it should be found that the whole
of the chloude of sodium has not been decomposed, and the nitric acid (if
any) which has been distilled over, as before mentioned, has not, after such
second distillation as aforesaid, been sufficient to complete such decomposition,
the decomposition of the whole of the salt must be completed by the addition
of a further portion of nitric acid to the contents of the pan or vessel, and
in order to ascertain whether the whole of the chloride of sodium has been
decomposed, a small additional portion of nitric acid may (by means of the
funnel before mentioned) be added to the contents of the pan or vessel; and
if the decomposition has been complete the additional quantity of the acıl
will not cause any more hydrochloric acid to be evolved, but, if incomplete,
further portions of nituc acid must be added from time to time until a com-
plete decomposition has been produced. The first distillation will, however, I
believe (if carefully performed) be found sufficient to produce the desued
result, and if it should happen to be imperfectly performed, it will arely bo

page_text: necessary to add more than five or six additional parts of nitric acid, in order
to complete the process so as to obtain nitrate of soda free from any admix-
ture with chloride of sodium. When this process has been thus far com-
pleted by the distillation of all the free acid from the contents of the pan or
vessel, the residue remaining in the pan or vessel will be a liquid nitrate of
soda, which I then transfer to another vessel, and supply such a degree
of heat as necessary, for the purpose of driving off the water of solution, so
as to produce the nitrate of soda in a dry state, and thus render it fit for
undergoing the process or processes herein-after described to which it is to be
subjected for the purpose of producing soda, as herein-after described. The
mode in which chloride of potassium is to be decomposed, according to this
part of my said Invention, so as to obtain nitrate of potash, is precisely the
same as herein-before described with reference to the decomposition of
chloride of sodium, so as to obtain nitrate of soda; but the proportions of
the materials to be used are to be varied. for it will be found that seventy-six
parts of chlonde of potassium may generally be decomposed by such a quan-
tity of nitric acid as will be equal to fifty-four or fifty-five parts of pure
nitric acid.
The second part of my said Invention (as I have already stated) consists of
a mode of obtaining soda or potash from a nitrate or muriate of those alkalies
respectively (such nitrates and munates being well-known salts), by subjecting
such nitrate ori munate to the chemical action of one or more of the substances,
by chemists called caiths, at a red heat, so as to decompose it as herein-after
described. This part of my said Invention is, in fact, applicable to the obtain-
ing of soda or potash from a muriate of such alkali, but I have found that in
performing this part of my said Invention upon a muriate of either of those
alkalies, in order to obtain the alkah which forms its base, the loss of material
and the cost of the process is so much greater than when I operate upon a
nitiate of either of the alkalies. I have named for a similar purpose that it
is much better and more economical either to select a nitrate of soda or potash
as the salt from which to obtain the alkalı, or to convert the munate of the alkali
into a nitrate (according to the process herein-before described as the first part
of my Invention), and then to subject such nitiate to the part of my said Inven-
tion now to be described, for the purpose of obtaining its alkalı freed from the
acid with which it is united The earths which I use for the purpose of effecting
this part of my Invention may be either alkaline earths, or any other descp-
tion of earths, all of such earths being now by chemists usually called oxides, or
metallic oxides. The oxide of iron, and the other metallic oxides, are also
applicable for a similar purpose, but will not produce results equally beneficial.

page_text: The materials which I use in performing this part of my Invention are to be
placed in a cylinder or other vessel, of a convenient form and size (according
to the quantity of material to be operated upon, and made of iron, fire clay, or
any other substance that will bear icd heat. The vessel must have an orifice
for the introduction of the materials, and such orifice must be constructed so as
to be capable of being made air-tight after the introduction of the materials.
The vessel must also have another orifice, into which may be inserted one end
of a pipe or tube, which communicates with a chamber of receiver, into which
the gaseous products of the process may be distilled and condensed. The
vessel must also be constructed or placed so that the contents of it may be
heated to a red heat and upwards, by any of the modes well known, and
applicable to such a purpose. Into a vessel, such as I have described, I
introduce the nitrate of soda or potash to be operated upon in a powdered
state, and intimately mixed with the earth (also in powder), by means of which
I intend to decompose the salt. I generally employ equal parts (by weight)
of the salt and of the carth, for the purpose of effecting the intended decom-
position, and from the experience I have had I am led to believe that these are
the best proportions of the materials which can be adopted for the purpose of
producing the desired effect The proportions of the materials may, however,
be varied, and the same decomposition be ultimately produced, but I believe
that if these proportions are much altered the desired decomposition will not
be effected either so speedily or so economically, if so effectually. The
materials having been introduced into the vessel, and the aperture closed and
made air-tight, the pipe or tube communicating with the condensing chamber
or receiver being also inserted, heat is to be applied, so as to make the mate-
11als in the vessel of a red heat or upwards, and this degree of heat must be
kept up until this part of the process has been completed. The effect of
applying heat in the way I have mentioned will be to drive off the acid of the
nitiate of soda or potash, and I believe that that is effected by the earth, and
the base of the salt with which it is mixed, having a stronger chemical or
elective affinity for each other at that high temperature than either the earth
or the alkali and the acid have for each other. But whatever may be the
play of affinities or chemical principles which produce the effect, the result
will be (if the process be properly conducted) that the whole of the nitric acid
will be distilled or driven off in a state of gas into the chamber or receivei,
where it may be condensed and collected by any of the means usually employed
for that purpose. When I employ lime for the decomposition of nitrate of soda
I generally find the exposure of the materials to a red heat for about twelve
hours sufficient to drive off the whole of the acid. The completion of the

page_text: process will be known to the operator by the pipe or tube before mentioned
ceasing to give out any more acid gas; but, if desued, a further test may be
adopted, which consists of withdrawing a small portion of the material from
the vessel, and throwing it into a fire, when, if no deflagration be thereby
produced, it will be known that the whole of the nitric acid has been diven off
In performing this part of my process I prefer to employ lime for the decom-
position of the nitrate of soda or potash, because that earth can generally be
obtained more cheaply and with greater facility than any of the other earths
And it is not at all neces-
which would produce an equally beneficial result
sary that the limo used in performing this part of my Invention should be
perfectly pure, for a magnesian lime will answer the purpose quite as well
The alkaline earths, respectively called lime, barytis, strontia, and magnesia, or
any mixture of any two or more of them, will all equally well (so far as I have
been able to ascertain) produce the same result in this process of decomposing a
nitrate of soda or potash, as before described. When I decompose a nitrate of
soda or potash by means of a carbonate of either of the four earths I have just
named, or a combination of any two or more of such carbonates, the dry resi-
duum which will remain in the vessel after the completion of the distillation or
process just described will be a combination of a carbonate of the alkalı and
When this residuum has
the earth or earths in a caustic state, or nearly so.
become cool the alkali is to be separated from the earthy matter by washing,
the alkali being soluble and the earthy matters insoluble. The solution of
the alkali, being separated from the earthy matter in any mode usually adopted
for that purpose, may then either be evaporated to dryness or christalized, as
may be desued. When I decompose a nitrate of soda or potash by means of
either of the four earths I have named, or a combination of any two or more
of them in a caustic state, the diy residuum which will be left in the vessel
after the completion of the distillation or process just described will be a
combination of the alkalı and earth or earths, both or all in a caustic state.
In order to separate the alkali from the carthy matter in this case I dissolve
the alkali in as small a quantity as possible of warm water, and then carefully
drain the clear solution from the undissolved carthy matter. The earths I
have named are very slightly soluble in water, and the water in which the
alkalı is dissolved being saturated with the alkali, there will scarcely be any
portion of carthy matter dissolved and carried off in the alkaline solution if
the process is performed correctly. The alkaline solution may then be evapo-
rated to dryness, or otherwise disposed of, as may be desued The caustic
alkaline solution or alkali, produced in the manner just described, is applicable
in the manufacture of soap, and may be used for many other purposes.

page_text: Either of the earths respectively called alumina and silica alone, or a combina-
tion of both on either of them with all or any of the alkaline earths before
mentioned, may be applied in the decomposition of a nitrate of soda or potash,
by the distillation or process before described But when the earth or caiths,
or any portion of the earth on earths used for the decomposition of a nitrate of
soda or potash is composed of alumina or silica, the alumina or silica will be
chemically united to the alkali contained in the residuum in the vessel after
the completion of the distillation, unless some portion of the earth or earths
used in the process were in the state of a carbonate, so as to yield carbonic
acid to form the alkali into a carbonate, and unless the whole of the alkali in
such a case is formed into a carbonate; in this way that portion of it which is
in a caustic state will be chemically united with any alumina or silica which
may have been used in the process. When the alkaline product of this
distillation or process is thus combined with any portion of alumina or silica,
the two latter, or one of them, being in excess, the compound must be rendered
soluble by the addition of a sufficient quantity of the respective alkali fused
together with the product of the distillation, and those earths, or either of
them, may now be got rid of by combining the alkali with a sufficient quantity
of carbonic acid by any convenient means, when the alkali may be dissolved in
water, and the earth or earths being now insoluble, the alkaline solution may
be separated and treated as before mentioned. In consequence, however, of
the tendency of these alkalies to react chemically with alumina and silica, as
before mentioned, I believe that it will seldom be found beneficial to use those
earths in the decomposing of nitrate of soda or potash, unless, indeed, in cases
where the mixture of the alkalı with either of those earths would not unfit the
alkalı for the purposes to which it is intended to be applied. Thus, if the alkali
be intended to be used in the manufacture of glass, it would not be rendered
unfit for that purpose by being united to or mixed with a portion of silica.
The earth or carths which may have been used for the decomposition of a
muriate or nitrate of soda or potash, as before described, may, after the alkali
has been washed or separated therefrom, be again used for the like purpose.
Although I have described or mentioned apparatus which I use for the
purposes of my Invention in manner aforesaid, yet it must be understood that
I do not claim such apparatus, or any part thereof, as of my said Invention;
nor do I claim as of my Invention the mode of collecting or condensing
aiuriatic or hydrochloric acid gas, or nitric acid gas, as herein-before mentioned
or described in connection with my said Invention. And I hereby declare
that I claim as of my Invention,
Firstly, the mode of decomposing muriate of soda or potash by hydrated

page_text: nitric acid, at the temperature and in manner herein-before described, so as to
form a nitrate of soda or potash, from which soda or potash may with greater
facility be manufactured or obtained by the second part of my Invention, as
herein-before mentioned; and,
Secondly, the mode of decomposing alkaline salts by means of earths, for
the purpose of manufacturing soda and potash, in the manner herein-before
described.
In witness whereof, I, the said Francois Stanislas Meldon de Sussex,
hath hereunto set my hand and seal, this Twenty-ninth day of
December, in the year of our Lord One thousand eight hundred and
forty-six.
F. S. MELDON (L.s.) DE SUSSEX.
AND BE IT REMEMBERED, that on the Twenty-ninth day of Decem-
ber, in the year of our Lord 1846, the aforesaid Francois Stanislas Meldon
de Sussex 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 witten. And also the Specification
aforesaid was stamped according to the tenor of the Statute made for that
purpose.
Enrolled the Twenty-ninth day of December, in the year of our Lord One
ht hundred and forty-sIX.