Using a Combination of Sulphuric Acid and Hydrochloric Acid for the Decomposition of Chlorides, Sulphides, Sulphates, and of Sulphuretted Hydrogen.
Year: 1891

page_text: Date of Application, 17th Mar., 1891
Complete Specification Left, 11th Dec., 1891-Accepted, 12th Mar., 1892
PROVISIONAL SPECIFICATION.
Using a Combination of Sulphuric Acid and Hydrochloric Acid for
the Decomposition of Chlorides, Sulphides, Sulphates, and of
Sulphuretted Hydrogen.
Wal
1 JAMES PLDDER of 1 D STA App
Apparatus Manufacturer do hereby declare the nature of this invention to be
as follows:-
In the application of my invention to the treatment of mined rock salt I use as
an essential apparatus a Weldon chlorine still.
In the still I place a given quantity of mined salt, to which I add sufficient
sulphuric acid, combined or mixed with one-third of its bulk of hydrochloric
acid (HCl), but I do not wish to be confined to the exact quantity named as the
precise proportion will be determined by experience.
I apply steam to the salt until the latter is decomposed, and then run the liquor
into vat to crystallize.
I use remaining or residual liquor to combine with sulphuric acid for the next
operation. roast the crystals to drive off or evaporate remaining hydrochloric
acid and connect roaster and still with condensers to collect acid.
In the application of my invention to ordinary hand furnaces, these may be
worked as at present with ground rock salt by adding to the acid used, a certain
proportion of HCl worked at a lower heat.
In the application of my invention to the cylinder process, I acidulate the steam
used for decomposition (by sulphate of soda) with hydrochloric acid by forcing it
through a vessel containing this agent, or evaporating hydrochloric acid by heat
from pyrites burners and causing it to mix with sulphurous acid from said burners
before passing into cylinders.
In the application of my invention to the decomposition of sulphate of soda, I
add sufficient hydrochloric acid in a cold state as to decompose a given quantity
of calcium sulphide and adequate to decompose the acid in the sulphate of soda
into sulphurous acid, on completion I force carbonic acid through the solution to
carbonate the soda.
I may also apply my invention to the treatment of black ash waste (calcium,
sulphide and calcium carbonate) using the mixed hydrochloric and sulphuric acid
in equal proportions in Weldon still; the gases evolved I pass through a previously
neutralised solution to carbonate the soda by the action of the gaseous CO, I pass
the sulphurous acid over a heated surface, and thence into cylinders to produce
sodic sulphate.
In the application of my invention to metallic sulphides I proceed as follows:-
In a given volume of mixed acids (HCl and SH,O) 1 digest a given weight of
ore, sufficient sulphide of the metal being present to decompose the constituent
sulphuric acid. I apply the heat of combustion to assist the dissolution and to
evaporate the sulphurous acid. I admit and use air for the oxidation of the metals
after desulphuration, and pass gases (sulphurous acid) through cylinders to produce
sulphate of soda.
I
In the treatment of the sulphuretted hydrogen evolved in the Chance's process,
pass the gas through a bath of nixed acids (HCl and SH₂O) or the gas may
be passed through a coke tower, the mixed acids falling through the tower and
intercepting the sulphuretted hydrogen and decomposing it. I lead the resultant
gases to the cylinders to produce sulphate of soda.
In the application of my invention to the treatment of the salt in the Hargreaves'
cylinders, I add sulphate of soda in dust or liquid form to the salt before it is

page_text: cooked or roasted in the oven or cylinders, in order to prevent the salt from being
too closely packed in the cylinders and permit the gas to surround it. I provide
sufficient addition of sulphate of soda to ensure that each cake in the cylinder
contains on its surface a definite proportion of the added sulphate of soda, the latter
decomposes the steam acidulated with ICI that passes with sulphurous acid or
sulphuretted hydrogen into the cylinders.
Dated this 13th day of March 1891
JAMES PEDDER.
COMPLETE SPECIFICATION.
Using a Combination of Sulphuric Acid and Hydrochloric Acid for
the Decomposition of Chlorides, Sulphides, Sulphates, and of
Sulphuretted Hydrogen.
JAMES PEDDER 16 Doward Street Appleton in Widnes Lancashire Chemical
Plant Manufacturer 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:
In the application of my invention to the treatment of mined rock salt I use as
an essential apparatus a Weldon chlorine still.
In the still place a given quantity of mined salt, to which I add sufficient
sulphuric acid, combined or mixed with one-third of its bulk of hydrochloric
acid (HCI), but I do not wish to be confined to the exact quantity named as the
precise proportion will be determined by experience.
I apply steam to the salt until the latter is decomposed, and then run the liquor
into vat to crystallize.
use remaining or residual liquor to combine with sulphuric acid for the next
operation. I roast the crystals to drive off or evaporate remaining hydrochloric
acid and connect roaster and still with condensers to collect acid.
In the application of my invention to ordinary hand furnaces, these may be
worked as at present with ground rock salt by adding to the acid used, a certain
proportion of HCI worked at a lower heat to prevent the formation of free acid or
sodic bisulphate.
In the application of my invention to metallic sulphides I proceed as follows:-
In a given volume of mixed acids (HCI and SHO) I digest a given weight of
ore, sufficient sulphide of the metal being present to decompose the constituent
sulphuric acid. apply the heat of combustion to assist the dissolution and to
evaporate the sulphurous acid. I admit and use air for the oxidation of the metals
after desulphuration, and pass gases (sulphurous acid) through cylinders to produce
sulphate of soda.
In the application of my invention to the treatment of the salt in the Hargreaves
cylinders, add sulphate of sola-in dust or liquid form to the salt before it is
cooked or roasted in the oven or cylinders, in order to prevent the salt from being
too closely packed in the cylinders and permit the hydrochloric and sulphuric
acid gases to surround it.
I provide sufficient addition of sulphate of soda to ensure that each salt cake in
the cylinder contains on its surface a definite proportion of the added sulphate
of soda, the latter decomposes the steam (which has been acidulated with hydro-
chloric acid and sulphuric acid), that passes with sulphurous acid or sulphuretted
hydrogen into the cylinders of the Hargreaves type.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same may be performed I declare that what I claim
is included in the following paragraphs—
First The application of combined hydrochloric and sulphuric acids to the
treatment of mined alt (solic chloride) in a Weldon still in the manner
substantially as herein described.

page_text: Second-The application of hydrochloric acid to sulphuric acid for the treat-
ment of ground salt in ordinary hand furnaces substantially as herein described.
Third The acidulation of steam used for the decomposition of caked salt in the
Hargreaves cylinders with hydrochloric acid, substantially as herein described.
Fourth-The decomposition of metallic sulphides with mixed acids-as herein
described.
Fifth The preaddition, when treating salts in the manner described, and in
cylinders of the Hargreaves type, of sulphate of soda-in dust or liquid form-
to the salt cake to be treated to aid in the decomposition of the steam that has
been acidulated with hydrochloric acid substantially as herein described.
Dated this Fourth day of December 1891.
JAMES PEDDER.