Improvements in Treating Sulphate of Lime and other Oxidized Sulphur Compounds of Calcium to Obtain Sulphuretted Hydrogen and in Apparatus Employed therein.
Year: 1888

page_text: Improvements in Treating Sulphate of Lime and other Oxidized
Sulphur Compounds of Calcium to Obtain Sulphuretted Hydrogen
and in Apparatus Employed therein.
We ALEXANDER MACOMB CHANCE and JAMES FREDERICK CHANCE of Oldbury in
the County of Worcester Alkali Manufacturers do hereby declare the nature of this
invention to be as follows:-
Sulphate of lime and other oxidized sulphur compounds of calcium may be reduced
with formation of sulphide of calcium by heating them in a suitable furnace with a
sufficient quantity of carbonaceous matter; and the sulphide of calcium so obtained
may be mixed with water and treated in a series of vessels with gases containing
carbonic acid for the production of sulphuretted hydrogen suitable for the manufacture
or sulphurous and sulphuric acids or of sulphur, or for other purposes, precisely as is
set forth for the like treatment of alkali waste in our complete specification No. 8666
of the year 1887. Such substances as gypsum, old alkali waste, and others, may thus
be rendered available for the production of sulphuretted hydrogen suitable for the
purposes above mentioned.
Th: 10th Jan of 1000
J. T. KING,
Agent for the Applicants.

page_text: Improvements in Treating Sulphate of Lime and other Oxidised
Sulphur Compounds of Calcium to Obtain Sulphuretted Hydrogen
and in Apparatus Employed therein.
We ALEXANDER MACOMB CHANCE and JAMES FREDERICK CHANCE of Oldbury in
the county of Worcester Alkali Manufacturers, 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 :-
Sulphate of Lime and other oxidised sulphur compounds of calcium may be
reduced with formation of sulphide of calcium by heating them in a suitable furnace
with a sufficient quantity of carbonaceous matter; and the sulphide of calcium so
obtained may be mixed with water and treated in a series of vessels with gases
containing carbonic acid for the production of sulphuretted hydrogen suitable for the
manufacture of sulphurous and sulphuric acids or of sulphur, or for other purposes,
precisely in the manner setforth for the like treatment of alkali waste in our complete
specification No. 8666 of the year 1887. Such substances as gypsum, old alkali
waste, and the like, may thus be rendered available for the production of sulphuretted
hydrogen suitable for the purposes above mentioned.
With the object of obtaining sulphuretted hydrogen from sulphide of calcium
reduced from oxidized sulphur compounds of calcium as above setforth we introduce
a mixture of the said sulphide of calcium and water; preferably as a thin cream, into
a series of vessels connected by pipes and furnished with inlet and outlet ways and
we pump or pass through some or all of such vessels gases containing carbonic acid.
We prefer to use the gases evolved from a closed limekiln consisting almost entirely
of carbonic acid and nitrogen-The first action of the carbonic acid is to decompose
the sulphide of calcium with evolution in the presence of water of sulphuretted
hydrogen, and this sulphuretted hydrogen is driven forward and meeting with further
quantities of sulphide of calcium is absorbed with production of sulphydrate of
calcium; so that at first the gases issuing from the last vessel contain little or no
sulphuretted hydrogen and may be delivered into the atmosphere, either directly
or through purifiers to free them from any sulphuretted hydrogen they may
contain.
When, after a time the issuing gases begin to contain sulphuretted hydrogen in
appreciable quantity, we close the outlet from the last vessel and open that from
some one of the intermediate vessels where we find that the issuing gases contain a
large proportion of sulphuretted hydrogen in consequence of the fact that the carbonic
acid is now acting upon the sulphydrate of calcium formed as aforesaid; and that for
each equivalent of carbonic acid absorbed two equivalents of sulphuretted hydrogen
are being evolved. We therefore conduct away separately these gases so long as they
contain sulphuretted hydrogen in sufficient quantity, preferably into a gas holder, and
apply them to any of the above mentioned purposes. When the quantity of
sulphuretted hydrogen becomes too small we close this outlet, and having emptied the

page_text: first vessel or vessels in which the decomposition of the sulphide of calcium has been
completed, and filled another or others later in the series with a fresh mixture of
sulphide of calcium and water, we resume our operations as at first and so proceed
continuously. If the sulphide of calcium contain coarse matters such as cinders we
prefer before treating it as above described to separate such coarser portions by
passing the mixture of sulphide and water through a sieve or grating or by any other
convenient means, and we may crush these coarser portions if desired and treat them
similarly to the rest. Or the whole of the sulphide may be treated so as to crush the
coarser portions of it before it is treated with the gases containing carbonic acid in the
series of vessels.
The process herein described for obtaining sulphuretted hydrogen from Sulphide of
Calcium is carried on in the manner and in the apparatus particularly described and
illustrated in our Complete Specification No. 8666 of the year 1887 or other approved
apparatus may be used.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed we declare that what
we claim is.
First. Reducing oxidised sulphur compounds of calcium to sulphide of calcium
and obtaining sulphuretted hydrogen therefrom substantially as setforth.
Second: Apparatus for furnacing oxidized sulphur compounds of calcium to obtain
sulphide of calcium and for treating such sulphide of calcium in a series of vessels to
obtain or yield sulphuretted hydrogen all substantially as herein before setforth.
Dated this 20th day of October 1888