IMPROVEMENTS IN THE MANUFACTURE OF CAUSTIC ALKALIES AND THEIR CARBONATES, AND CHLORINE AND VARIOUS SUB-PRODUCTS
Year: 1877

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lakė,
& Co., Patent Agents, Southampton Buildings, London, for the Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF CAUSTIC ALKALIES AND THEIR
CARBONATES, AND CHLORINE AND VARIOUS SUB-PRODUCTS." A communication
from abroad by David Clovis Knab, of Paris, France.
Sealed the 1st February 1878, and dated the 13th August 1877.
PROVISIONAL SPECIFICATION left by the said William Robert Lake at.
the Office of the Commissioners of Patents on the 13th August 1877:
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents;
Southampton Buildings, London. "IMPROVEMENTS IN THE MANUFACTURE OF
CAUSTIC ALKALIES AND THEIR CARBONATES, AND CHLORINE AND VARIOUS SUB-
PRODUCTS." [A. communication from abroad by David Clovis Knab, of Paris,
France.]
This Invention relates to an improved method of obtaining, by the use of oxide
of lead or acetate of lead, caustic alkalies, such as potash and soda or their
carbonates, and chlorine from alkaline chlorides, with regeneration of the raw
materials excepting the alkaline chlorides, thereby causing the latter to yield
(without other cost than is involved in such regeneration) a caustic alkali or its
carbonate and chlorine. Various sub-products may also be produced, such as
carbonate of lead, acetate of soda, or of potash, acetone and the like; but as the
demand for these sub-products is not sufficiently large I do not propose to manu
facture them at present for sale.
The principles upon which the chief feature of this Invention is based are alieady
known, but have not hitherto been carried into practical use.
In carrying the said Invention into practise I employ oxide of lead or litharge
for effecting the re-actions, and under conditions very different from those with
which attempts have hitherto been made, and I produce under these conditions a

page_text: complete course of manufacture. I take, for example, sea salt or chloride of sodium,
which I mix with its equivalent of litharge, that is to say, according to the purity
of the salt, about from 74 to 76 parts of salt for 130 parts of litharge; or if chloride
of potassium has to be treated 100 parts of this chloride to 130 parts of litharge.
In either case I add water from 4 to 5 times the weight of the chloride. I place
the whole in a closed mechanical crushing or pounding apparatus, which is heated
by steam to from 80 to 90° centigrade. The said apparatus is then caused to
operate, and in one hour and a half at most the re-action will be completed; that
is to say, the salts and litharge will have entirely disappeared, and be replaced by a
white paste in which no trace of litharge will be found.
I desire to point out that with means described in books on chemistry for
producing, for example, what is known as "Turner yellow," from 5 to 6 times more
litharge than salt is used, and the re-action instead of taking one hour and a half
at the most required several days.
In continuing the process according to this Invention after having extracted the
paste from the pounding or crushing apparatus I allow it to cool and to drain, then
I wrap it in cloths and submit it to hydraulic pressure. The said pressure has the
effect of extracting at once 95 per cent. of the caustic liquor, and there remains a
very hard cake of chloride of lead perfectly white. The said chloride of lead is
again pounded with the same quantity of water as before, and filtered and pressed,
and the wash liquor serves as a vehicle for a succeeding operation instead of pure
water. The caustic lye is evaporated, and a little chloride of lead from the unde-
composed marine salt is deposited by concentration. For safety I precipitate the
last traces of lead by carbonate of soda or of potash; then I complete the operation
by well-known means. This re-action may be effected perfectly under the conditions
above described, but this is not all; the chloride of lead has to be regenerated
either again as oxide to serve thus indefinitely, or as a product for commercial
purposes; and I operate as follows, that is to say, I add to the chloride of lead the
equivalent of the lead in common carbonate of ammonia; I place the mixture in
another closed pounding or crushing apparatus, but do not heat it, and with a
sufficient quantity of water to form a liquid paste. At the end of twenty minutes
at the most the re-action is finished, and the process has produced hydrochlorate of
ammonia in solution in the water, and carbonate of lead or white lead of a beautiful
white color, which may be used at once for manufacturing purposes. By means
of pressure and washing I completely extract the solution of hydrochlorate of
ammonia.
In the event of the demand not being sufficiently large I decompose, excluding
the air, this carbonate of lead by heat, and obtain again oxide of lead, which is
again used in the manufacture, also carbonic acid, which is collected and serves to
carbonate the ammonia. As to the hydrochlorate of ammonia I regenerate the
ammonia with lime by means already known.
It will be seen that by the process carried into practise according to this Invention
the circle of production is unbroken excepting the insignificant losses of oxide of
lead and those of ammonia, which are of small importance. I employ as the raw
material absolutely nothing but the chlorine.
If the said process should come into general use hydrochloric acid and conse-
quently chlorine would disappear, and it would become necessary to regenerate the
chlorine of the hydrochlorate of ammonia. I effect this perfectly by treating the
hydrochlorate of ammonia, not with lime for disengaging from it the ammonia, but
with protoxide of manganese, which effects the same object, and leaves as a residuum
chloride of manganese, which latter I dry and calcine to a dark red in closed retorts,
causing a current of air to pass through by any of the methods already in use.
Naturally sesqui-oxide of manganese is formed, which remains as a residuum; it
becomes liberated from the chlorine mixed with the azote of the air, and I utilize it
by any of the well-known means. The sesqui-oxide of manganese does not decompose
the hydrochlorate of ammonia, and it is necessary to transform it into protoxide.
This is readily done by removing the excess of oxygen by means of heated sulphur.

page_text: Sulphurous acid is formed which is used in sulphuric acid chambers, and there
remains protoxide of manganese of a greenish color, which may be used over again
constantly. This re-action is very clear, and may be stated as follows, that is
to say,
2 (Mn² 0³) × S
.
= So2 x 4 Mn O.
It will be seen that the quantity of sulphur to be employed is a very small matter,
since to produce theoretically nearly 1,800 kilogrammes of protoxide of manganese
only 200 kilogrammes of sulphur are required, giving, theoretically, nearly 1,800
kilogrammes of chlorine.
It will be seen that from the commencement to the end of the said process the
circle of production is quite unbroken, taking the said process as a whole, employing
only marine salt or chloride of potassium with a small quantity of sulphur (which
itself is used in the form of sulphurous acid), and from these chlorides are obtained.
soda and potash and chlorine.
I obtain the same results indirectly and as distinctly by treating the same.
alkaline chlorides with acetate or pyrolignite of lead. Chloride of lead and alkaline
acetate are also produced. I regenerate the oxide of lead by the processes above:
described.
As regards the acetates they may in part be delivered directly for use; or they
may be decomposed by heat, producing acetone, which may in future be useful in
manufacture. There remains as a residuum the carbonated base. In treating the
acetate of soda or of potash with bicarbonate of ammonia I produce bicarbonate.
from the base and acetate of ammonia, which, treated with heat by regenerated
oxide of lead, liberates ammonia and reproduces acetate of lead.
This modification of the said process might, under certain circumstances, be found
to be of considerable importance.
:

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Robert Lake in the Great Seal Patent Office on the
12th February 1878.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. 'IMPROVEMENTS IN THE MANUFACTURE OF
CAUSTIC ALKALIES AND THEIR CARBONATES, AND CHLORINE AND VARIOUS SUB-
PRODUCTS." A communication from abroad by David Clovis Knab, of Paris,
France.
This Invention relates to an improved method of obtaining by the use of oxide of
lead or acetate of lead caustic alkalies, such as potash and soda, or their carbonates,
and chlorine from alkaline chlorides, with regeneration of the raw materials,
excepting the alkaline chlorides, thereby causing the latter to yield (without other
cost than is involved in such regeneration) a caustic alkali or its carbonate and
chlorine. Various sub-products may also be produced, such as carbonate of lead,
acetate of soda or of potash; acetone, and the like; but as the demand for these.
sub-products is not sufficiently large, I do not propose to manufacture them at
present for sale.
The theory or principle upon which the chief feature of this Invention is based
has been known for many years, but as the same has never been applied to the pro-
duction of soda or potash it has obviously not hitherto been made practically or
_ commercially useful.
In carrying the said Invention into practice I employ oxide of lead or litharge
for effecting the reactions under conditions very different from those under which
attempts have hitherto been made, and I produce under these conditions a complete
course of manufacture. I take, for example, sea salt or chloride of sodium, which
I mix with its equivalent of litharge, that is to say, according to the purity of the
salt, about from 74 to 76 parts of salt for 130 parts of litharge, or if chloride of
potassium is to be treated I use 100 parts of this chloride to 130 parts of litharge.
In either case I add a quantity of water equal to from four to five times the weight
of the chloride. I place the whole in a closed crushing or pounding apparatus,
which is heated by steam to from 80 to 90 degrees centigrade. The said apparatus
is set in motion, and in one hour and a half at most the reaction will be completed,
that is to say, the salts and litharge will have entirely disappeared, and will be
replaced by a brilliantly white paste, in which no trace of litharge will be found.
There have been already great changes with regard to the means described in
books on chemistry for producing for example what is known as "Turner yellow;"
from five to six times more litharge than salt were used, and the reaction instead of
taking at the most one hour and a half, required several days.
Returning to the description of this. Invention, after having extracted the paste
from the pounding or crushing apparatus, I allow it to cool and to drain, then I
wrap it in cloths and subject it to hydraulic pressure; this pressure has the effect of
extracting at once 95 per cent. of the caustic liquor, and there remains a very hard
cake of chloride of lead perfectly white. This chloride of lead is again pounded
with the same quantity of water as before, and filtered and pressed, and the wash-
liquor serves instead of pure water as a vehicle for a succeeding operation. The
caustic lye is evaporated, and a small quantity of chloride of lead from the unde-
composed sea salt is deposited by concentration. For safety I precipitate the last
traces of lead by carbonate of soda or of potash, then I complete the operation by
well known means. This reaction may be effected perfectly under the conditions
above described, but this is not all; the chloride of lead has to be regenerated either
again as oxide to serve thus' indefinitely, or as a product for commercial purposes; I
therefore proceed as follows, that is to say, I add to the chloride of lead the equiva-
lent of the lead in common carbonate of ammonia, I place the mixture in another
closed pounding or crushing apparatus, but in this case without heating it, and with

page_text: that I claim, the employment of oxide of lead or acetate of lead for obtaining
directly in the one case and indirectly in the other case caustic alkalies such as
potash or soda, or their carbonates, or for obtaining chlorine from alkaline chlorides
with regeneration of the raw materials, except the alkaline chlorides; the latter
yielding, without other cost than that of regeneration, caustic alkali or its car-
bonate, and chlorine, it being understood that the manufacture of sub-products such
as carbonate of lead; acetaté of soda; or of potasli; acetone, or the like, may be
according to circumstances, as above set forth.
In witness whereof, I, the said William Robert Lake, have hereunto set iny
hand and seal, this Twelfth day of February, in the year of our Lord
One thousand eight hundred and seventy-eight:
M
PAR
WM. ROBT. LAKE. (L.S.)