IMPROVEMENTS IN THE MANUFACTURE OF CAUSTIC POTASH AND SODA
Year: 1882

page_text: LETTERS PATENT to William Lloyd Wise of 7 Whitehall Place in the City
"
of Westminster for an Invention of IMPROVEMENTS IN THE MANUFACTURE
OF CAUSTIC POTASH AND SODA Communicated to him from abroad by
La Société anonyme Lorraine Industrielle of Paris in the Republic of
Trance
PROVISIONAL SPECIFICATION left by the said William Lloyd Wise at the
Office of the Commissioners of Patents on the 30th August 1882.
WILLIAM LLOYD WISE of 7 Whitehall Place in the City of Westminster,
"IMPROVEMENTS IN THE MANUFACTURE OF CAUSTIC POTASH AND SODA" (a com-
munication to me from abroad by La société anonyme Lorraine Industrielle of
Paris in the Republic of France)
•
This invention has for object improvements in the manufacture of caustic potash
& soda and is based on the following operations.
1.) The decomposition of chloride of potassium or chloride of sodium (according
as the product desired is caustic potash or caustic soda) by oxide of lead in presence
of an equivalent of water to produce the hydrates KO, HO, or Na O, HO, the
reaction producing chloride of lead insoluble in alcohol, and caustic potash or soda
as the case may be, very soluble in alcohol.
2 The extraction by alcohol of the caustic potash or soda from the pasty
mixture which results from the above reaction, the alcoholic solution of caustic
alkalies being easily separated by reason of the great density of the chloride
of lead.
3.) The evaporation of the alcoholic solution to recover the greater portion of the
alcohol; the addition of water to the alkaline residue to separate by distillation the
last traces of alcohol; and final concentration to the solidifying point, as by the
ordinary processes.
4.) The conversion of the chloride of lead into metallic lead (and afterwards into
oxide of lead or litharge) either by the wet process by precipitation by white cast

page_text: iron (yielding chloride of iron as a residue) or by metallurgical processes, so as t
make the litharge serve indefinitely with the exception only of such losses as an
inherent in every manufacture.
These operations constitute a complete series and give definitely and directly,
1.) From Chloride of Potassium, pure caustic potash.
2.) From Chloride of Sodium, pure caustic soda.
3.) And for residue chloride of iron, which is valuable as a disinfectant.
"
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Lloyd Wise in the Great Seal Patent Office on the
27th February 1883.
WILLIAM LLOYD WISE late of 7 Whitehall Place in the City of Westminster
now of 46 Lincolns Inn Fields in the County of Middlesex IMPROVEMENTS IN
THE MANUFACTURE OF CAUSTIC POTASH AND SODA (a communication to me from
abroad by La Société anonyme Lorraine Industrielle of Paris in the Republic of
France)
This invention has for its object improvements in the manufacture of Caustic
Potash and Soda.
According to this invention Caustic Potash and Caustic Soda are obtained
direct from their Alkaline Chlorides by taking advantage of the well known
re-action of Litharge on the Chlorides and the insolubility of the resulting Chloride
of Lead in Alcohol. The process has hitherto failed in consequence of the difficulty
of removing and recovering the Lead.
In carrying out the invention chloride of potassium or Chloride of Sodium
(according as the product desired is caustic Potash or caustic Soda) is added to
Litharge or oxide of Lead with the addition of an equivalent of water necessary
to produce KO. HO or Na O. HO. The reaction is completed in a short time by
simply mixing, or very rapidly by grinding them together. A very white very
thick paste is produced consisting of a mixture of nearly insoluble Chloride of Lead
and caustic Potash or Soda (according to the alkaline chloride employed).
To extract the Caustic Alkali the above paste is washed methodically with
Alcohol which need not be stronger than 50 per cent or specific gravity 0·9335 at
60° F. which readily dissolves caustic Alkalies but in which Chloride of Lead is
completely insoluble. In consequence of the great density of Chloride Lead it
settles rapidly and compactly, therefore the alcohol employed need not be more
than one quarter of the weight of Alkali present.
The solution of the caustic Alkali now free from Lead is distilled to remove and
recover the alcohol, a small quantity of water being added towards the end of the
process to drive off the last traces of Alcohol.
The required Caustic Potash or Soda will be found left behind in the retort.
The lead can be recovered by dissolving the Chloride of Lead, after the removal

page_text: of the Alkali, in hot water and precipitating it with iron such as white cast iron,
which throws down the Lead in a metallic state. The lead can be oxydized by
ordinary processes reproducing Litharge. The liquid contains Chloride of Iron
which can be employed as a disinfectant. It is superior to sulphate of iron and
can by the above process be obtained in large quantities.
The lead can also be recovered by any of the ordinary metallurgical processes.
Having thus described the nature of the said invention and the manner in which
it is to be performed or carried into effect as communicated to me as aforesaid I
would have it understood that what is considered to be novel and original and is
therefore claimed as secured to me by the hereinbefore in part recited Letters
Patent is
1. The manufacture of Caustic Potash or Caustic Soda by causing Litharge to
react on chlorides of potash or soda in the presence of water and subsequently
extracting the resulting alkalies with alcohol, substantially as described.
2. The hereinabove described complete process of manufacturing caustic potash
and caustic soda recovering the Litharge and obtaining Chloride of Iron.
In Witness whereof I the said William Lloyd Wise have hereunto set my
hand and seal this twenty seventh day of February in the year of our Lord
one thousand eight hundred and eighty three.
1
TTATS
HIAG