IMPROVEMENTS IN OXIDIZING ALKALI-MAKERS' VAT-LIQUORS
Year: 1879

page_text: LETTERS PATENT to Walter Weldon, of Rede Hall, Burstow, in the County of
Surrey, for the Invention of "IMPROVEMENTS IN OXIDIZING ALKALI-MAKERS'
VAT-LIQUORS." A commuication from abroad by Dr. Pauli, of the Rheinau
Chemical Works, Mannheim, Germany.
PROVISIONAL SPECIFICATION left by the said Walter Weldon at the Office
of the Commissioners of Patents on the 8th August 1879.
WALTER WELDON, of Rede Hall, Burstow, in the County of Surrey. "IMPROVE.
MENTS IN OXIDIZING ALKALI-MAKERS' VAT-LIQUORS." A communication from
abroad by Dr. Pauli, of the Rheinau Chemical Works, Mannheim, Germany."
#
The solutions or (vat-liquors" obtained by lixiviating crude soda or crude
potash manufactured by the Leblanc process usually contain sulphide of sodium
or sulphide of potassium, as the case may be, and these sulphides cause the
liquors to hold in solution sulphide of iron also. It is extremely important to free
the said liquors from these impurities, and one way of doing this is by oxidation.
The present Invention consists in effecting such oxidation by the aid of an oxide
of manganese continually regenerated, and acting only as a carrier of oxygen from
the air to the impurities in the vat-liquor. The Invention is performed by adding
to the vat-liquor a small quantity of any oxide of manganese in a fine state of division,
but preferably an artificial oxide, and then treating the liquor either by air alone or
preferably by air and steam. Under these conditions the oxide of manganese
continually gives up a portion of its oxygen to the sulphides in the vat-liquor, but
continually takes up more oxygen from the air. A very small proportion of oxide
of manganese will thus carry oxygen from the air to any quantity of sulphides in
the liquor treated. When the oxidation of the liquor has been carried sufficiently
far the liquor is allowed to settle, and the clear part is then drawn off from the
oxide of manganese and impurities which have deposited. More vat-liquor is then
added and the operation recommenced. The same quantity of oxide of manganese
will thus serve an indefinite number of times. Indeed, the oxide of manganese
would serve perpetually but for the impurities with which it gradually becomes.
charged. It is only when these have accumulated to an inconvenient extent that
the oxide need be removed and replaced by a fresh quantity. The oxide used may
conveniently be in the state of what is known to chlorine manufacturers as
"Weldon mud," which however should preferably be first washed free from chloride
of calcium. The treatment with air may be inade by any method, but that of
injection is preferable. The liquors should preferably be heated during the injection
of air into them. The experiments on which this Patent is based have been made
with a Korting's injector, which has the advantage of injecting enough steam with
the air to keep the liquors at a convenient temperature. When the air is injected
by means of a blowing-engine special means of heating the liquors by injection of
steam or otherwise should be provided.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Walter Weldon in the Great Seal Patent Office on the 7th
February 1880.
WALTER WELDON, of Rede Hall, Burstow, in the County of Surrey. "IMPROVE-
MENTS IN OXIDIZING ALKALI-MAKERS' VAT-LIQUORS." A communication from
abroad from Dr. Pauli, of the Rheinau Chemical Works, Mannheim, Germany.
"
The solutions or "vat-liquors obtained by lixiviating crude soda or crude
potash manufactured by the Leblanc process usually contain sulphide of sodium or
sulphide of potassium, as the case may be, and these sulphides cause the liquors to
hold in solution sulphide of iron also. It is extremely important to free the said
liquors from these impurities, and one way of doing this is by oxidation. The
present Invention consists in effecting such oxidation by the aid of an oxide of
manganese continually regenerated, and acting only as a carrier of oxygen from the
air to the impurities in the vat-liquor. The Invention is performed by adding to
the vat-liquor a small quantity of any oxide of manganese in a fine state of
division, but preferably an artificial oxide, and then treating the liquor either by
Under these conditions the oxide of man-
air alone, or preferably by air and steam.
ganese continually gives up a portion of its oxygen to the sulphides in the vat-liqour,
but continually takes up more oxygen from the air. A very small proportion of oxide
of manganese will thus carry oxygen from the air to any quantity of sulphides in the
liquor treated. When the oxidation of the liquor has been carried sufficiently far the
liquor is allowed to settle, and the clear part is then drawn off from the oxide of
manganese and impurities which have deposited. More vat-liquor is then added and
the operation recommenced. The same quantity of oxide of manganese will thus
serve an indefinite number of times. Indeed, the oxide of manganese would serve
perpetually but for the impurities with which it gradually becomes charged. It
is only when these have accumulated to an inconvenient extent that the oxide
need be reinoved and replaced by a fresh quantity. The oxide used may con-
"Weldon
veniently be in the state of what is known to chlorine manufacturers as
mud," which however should preferably be first washed free from chloride of
calcium. The treatment with air may be made by any method, but that of
injection is preferable. The liquors should preferably be heated during the
injection of air into them. The experiments on which this Patent is based have
been made with a Korting's injector, which has the advantage of injecting enough
steam with the air to keep the liquors at a convenient temperature. When the air
is injected by means of a blowing-engine special means of heating the liquors by
injection of steam or otherwise should be provided,
Having now described and particularly ascertained the nature of the said Inven-
tion, and in what manner the same is to be performed, I claim as the Invention to
be secured to me by the hereinbefore in part recited Letters Patent, the use and
re-use of a small quantity of oxide of manganese as a carrier of oxygen to the
sulphides in alkali-makers' vat-liquors, substantially as is set forth above.
In witness whereof, I, the said Walter Weldon, have hereunto set my hand
and seal, this Seventh day of February, in the year of our Lord One thousand
eight hundred and eighty.
WALTER WELDON. (L.S.)