Improvements in the Manufacture of Caustic Soda, Carbonate of Soda, and Sulphide of Sodium.
Year: 1896

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 18 of the Patents, &c., Act, 1883), as allowed>
by the decision of the Comptroller General of the 17th day of May 1897.
Date of Application, 6th Jan., 1896
Complete Specification Left, 9th Sept., 1896-Accepted, 21st Nov., 1896
Improvements in the Manufacture of Caustic Soda, Carbonate of
Soda, and Sulphide of Sodium.
HENRY ROBERT ANGEL 7 St. Helen's Place London E.C. Ship Owner do-
hereby declare the nature of this invention to be as follows:-
I produce caustic soda and carbonate of soda, by mixing roasted zinc blend
sulphide ores with sulphate of soda iron oxide and coal or coke. This blend is put
into a cupola or other furnace and smelted.
During the process of smelting, the iron and zinc oxides turns the sulphate of
soda into caustic and at the same time carbonate of soda is produced, both of which
can be recovered in solution by running the slag into water.
Sulphide of sodium is produced by mixing unroasted sulphide ores with sulphate
of soda, iron oxide and coal or coke. This blend is put into a cupola or other
furnace and during the process of smelting the sulphate of soda is turned into
sulphide which is recovered by running the slag into water.
Improvements in the Manufacture of Caustic Soda, Carbonate of
Soda, and Sulphide of Sodium.
HENRY ROBERT ANGEL 7 St. Helen's Place Loudon E.C. Ship Owner do
hereby declare the nature of this invention and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:
With sulphate of soda, or bi sulphate of soda (nitre cake) mix iron oxide or
metallic iron or ferrite of soda with coal or coke, and with roasted or unroasted
zinc blend or other ores.
Place this mixture into a cupola blast furnace or into a V shaped furnace heated
by a commingling of steam with petroleum or other inflammable matter.

page_text: During the process of smelting the ores if a V shaped furnace be used the
sulphate of soda is changed by the carbon into sulphide of sodium, and the
oxide of iron in combination with the oxides of lead and zinc converts the sulphide
of sodium into an oxide of soda and this is recovered as caustic soda by running
the molten slag from the furnace into cold water after the lead and precious
metals have been extracted.
A portion of the charge is converted into carbonate of soda by the carbonic
acid gas thrown off by the coke, and a portion remains as sulphide of sodium
if unroasted ores are used, but if the ores are well roasted before treatment,
or if a large quantity of iron is used this entirely disappears, and it leaves the
solution about caustic and carbonate of soda.
If a cupola blast furnace is used in the process the sulphate of soda must be
converted into sulphide by burning out the oxygen with small coal as a preparatory
process and in every case the results will be improved by this. Carbonate of soda
can also be used in this manner.
Sulphide of sodium can be used direct in place of sulphate, in the treatment
of these ores, and the results obtained will be the same, and to every ton of
ore smelted ton of sulphide of sodium and ton of iron oxide must be employed,
and double this quantity, if sulphate of soda is used, and the greater the quantity
employed, the greater will be the return of caustic soda recovered.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
The production and recovery of caustic soda carbonate of soda and sulphide of
sodium as "bye products" from the reduction of refractory and other ores.
Dated this 9th day of September 1896.
H. R. ANGEL.