IMPROVEMENTS IN OBTAINING FROM ALKALI WASTE SULPHURETTED HYDROGEN AND CALCIUM CARBONATE
Year: 1884

page_text: I, FREDERICK WILLIAM RENAUT, of The Cottage, Burstow (by Crawley), in
the County of Surrey, Secretary, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN OBTAINING FROM ALKALI WASTE SULPHURETTED
HYDROGEN AND CALCIUM CARBONATE" and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
This Invention relates to the previous Invention for which the Patent
numbered 2334 and dated the 29th. of January 1884 has been granted.
By the said previous Invention the sulphur of alkali-waste is recovered as
sulphuretted hydrogen, and its calcium as calcium hydrate, by mixing the
alkali-waste with water, treating the mixture with sulphuretted hydrogen, and
then evaporating the resulting solution of calcium sulphydrate. By evaporating
that solution of calcium sulphydrate, the calcium sulphydrate is caused to react
on water, in such wise that its calcium becomes precipitated as calcium hydrate
and its sulphur disengaged as sulphuretted hydrogen.
By the present Invention, the solution of calcium sulphydrate, obtained by
treating by sulphuretted hydrogen a mixture of alkali-waste with water, is
decomposed, instead of by evaporation, as in the said former Invention, by means
of carbonic acid gas, mixed or not with other gases. Its sulphur is thus disengaged
as sulphuretted hydrogen, and its calcium precipitated, instead of as hydrate, as by
the said previous Invention, as calcium carbonate.
The treatment by carbonic acid gas, or by a mixture of carbonic acid gas and
other gases, of the solution of calcium sulphydrate obtained by treating by
sulphuretted hydrogen a mixture of alkali-waste with water, may be performed in
any convenient way, and I do not confine myself to any particular method of
performing it; but it may be conveniently performed in tall cylindrical vessels,
similar to what are known in alkali works as Weldon oxidizers, except that they
should be closed at the top, but communicate by pipes or conduits with the
apparatus in which the sulphuretted hydrogen generated in them is to be utilized,
.
527

page_text: and the injection of carbonic acid gas, or of a mixture of carbonic acid gas and other
gases, into the solution of calcium sulphydrate charged into such vessels may be
performed in a manner similar to that by which air is injected into the contents of
Weldon oxidizers.
When it is desired to obtain the resulting sulphuretted hydrogen, mixed or not
with other gases, nearly or quite free from carbonic acid, the arrangements should
be such that the mixture of sulphuretted hydrogen gas and carbonic acid gas, or of
these gases with other gases, which passes off from one vessel in which solution of
calcium sulphydrate is treated by carbonic acid gas, should be passed through a
further quantity or further quantities of the said solution contained in another
vessel or vessels. This method of working will be well understood by practical
men.
.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I' claim is:
The obtainment of the calcium of alkali-waste as calcium carbonate and its
sulphur as sulphuretted hydrogen, by treating by carbonic acid gas, mixed or not
with other gases, the solution of calcium sulphydrate which is obtained by treating
by sulphuretted hydrogen a mixture of alkali-waste and water.