Improvements in and connected with the Obtainment of Chlorine and Sulphate of Lime.
Year: 1889

page_text: Date of Application, 26th Feb., 1889
Complete Specification Left, 23rd Nov., 1889-Accepted, 4th Jan., 1890
PROVISIONAL SPECIFICATION.
Improvements in and connected with the Obtainment of Chlorine
and Sulphate of Lime.
We, ARCHIBALD CAMPBELL, of 42 Whittaker Road, Upton Park, in the County of
Essex, Chemist, and WILLIAM BOYD, of 90 Regent Terrace, Stirling Road, Glasgow,
in the County of Lanark, Chemist, do hereby declare the nature of this Invention to
to be as follows, that is to say :-
Our said Invention has for its object the more complete aud economical utilisation
of the materials employed in obtaining chlorine; and a bye product of our processes
is sulphate of lime in a very pure condition and applicable for various useful
purposes.
The materials which we employ in carrying out our Invention are,-hydrochloric
acid, obtained in any suitable known way, as the source of the chlorine, -sulphuric
acid-lime, peroxide of manganese,and atmospheric oxygen.
We treat lime in the form of chloride of calcium obtained as a bye or waste
product in either the manganese-reconversion process known as Dunlop's or that
known as Weldon's; or we may use chloride of calcium obtained in any other
suitable known way.
To the solution of chloride of calcium we add a nearly
equivalent quantity of a solution of sulphate of manganese preferably keeping the
mixture neutral or slightly acid so that the sulphate of lime precipitated may be as
pure as possible. The sulphate of lime is settled, filtered, washed, dried, and other-
wise treated in known ways according to the use to which it is to be put or for
which it is to be sold.
A portion of the chloride of manganese formed in the reaction may be used for
absorbing hydrochloric acid, another portion being mixed with the liquor from the
ordinary chlorine stills together with a suitable quantity of chloride of calcium to
make a mixture fit for treatment by the Weldon manganese-reoxidising process.
Instead of using simple milk of lime in the Weldon reoxidising process, we mix
the lime in the solution of chloride of calcium, in which it dissolves to some extent,
thereby obtaining a thinner liquor or one with less water for a given quantity of
lime. Or the chloride of manganese may be concentrated by heat to the density
suitable for treatment by the Dunlop process.
The excess of chloride of manganese is concentrated to a suitable density such as
60 to 70 degrees, Twaddell, and is run into a mixing vessel in which it is mixed with
Weldon mud or with peroxide of manganese obtained by Dunlop's process. The
mixture is run into a still along with a further quantity of chloride of manganese and
a quantity of sulphuric acid equivalent to the chlorine present; and on applying
heat all or nearly all the chlorine is freed and driven off, leaving sulphate of
manganese. The sulphate of manganese, which is nearly pure is nentralised with the
mixed chloride and peroxide of manganese mud; and after settling the clear liquor
is separated and used for mixing with chloride of calcium as hereinbefore described.
For the operation in which chlorine is freed and driven off it is necessary to have
the manganese mud and chloride of manganese as free as possible from calcium; and
to this end the mud is run in excess into a chlorine still along with hydrochloric acid
sufficient for the mud together with as much more as will dissolve all the calcium
present. When the free chlorine has been driven off, the remaining contents of the
still are allowed to settle; and the clear liquor is drawn off, and may be used in the
manganese-reoxidation part of the processes, or for being mixed with sulphate of
manganese to form sulphate of lime. In this last described way of working only a
part of the chlorine of the hydrochloric acid will be freed; but the remaining part
will be obtained from the chlorides of calcium and of manganese in the manner
hereinbefore described,

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When the clear liquor has been drawn off the remaining mud is filtered, pressed,
and washed to render it practically free from calcium chloride. The weak washings
from the precipitated sulphate of lime and containing chloride of manganese can be
used for this purpose as they are free from calcium salts; with the advantage of
reducing considerably the volume of water entering the operations. The cakes
obtained are,
in a suitable vessel, mixed with solution of chloride of manganese
already freed from calcium chloride and the mixture is run into a still along with
sulphuric acid as hereinbefore described. In the still we prefer to have the peroxide
of manganese in excess rather than the sulphuric acid, so that the residual liquid
will be practically neutral. Any remaining excess of peroxide of manganese
can be separated by settling or be added to the fresh materials for a subsequent
operation.
Impurities from the chemicals used and which will tend to accumulate in the
liquors and precipitates are by preference removed or prevented from reaching an
injurious or objectionable quantity, by periodically separating a suitable proportion of
the residual liquor of the stills in which the first portion of the chlorine is evolved,
precipitating impurities from that proportion and returning the liquor to the
remainder.
Dated this Twenty-fifth day of February 1889
EDMUND HUNT,
Applicants' Agent.
COMPLETE SPECIFICATION.
Improvements in and connected with the Obtainment of Chlorine
and Sulphate of Lime.
We, ARCHIBALD CAMPBELL of 42 Whittaker Road, Upton Park, in the County of
Essex, Chemist, and WILLIAM BOYD, lately of 90 Regent Terrace but now of
6 Broompark Terrace, Glasgow, in the County of Lanark, Scotland, Chemist, 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—
Our said Invention has for its object the more complete and economical utilisation
of the materials employed in obtaining chlorine; and a bye product of our processes
is sulphate of lime in a very pure condition and applicable for various useful
purposes.
The materials which we employ in carrying out our Invention are,--hydrochloric
acid, obtained in any suitable known way, as the source of the chlorine,-sulphuric
acid-lime-peroxide of manganese-and atmospheric oxygen.
We separate a portion of the chlorine of the hydrochloric acid in the ordinary
way by heating a mixture of the acid, peroxide of manganese, and water; and we
obtain a large additional quantity of chlorine from chloride of manganese formed in
the ordinary process and from treating chloride of calcium with sulphate of
manganese. And we arrange and combine the various processes in such a manner
as to economically obtain a large aggregate production of chlorine whilst repeatedly
reconverting and reusing the inanganese and making sulphate of lime as a useful
bye product.
We treat lime in the form of chloride of calcium obtained as a bye or waste
product in either the manganese-reconversion process known as Dunlop's; or that
known as Weldon's; or we may treat chloride of calcium obtained in any other
suitable known way. To the solution of chloride of calcium we add a nearly
equivalent quantity of sulphate of manganese, preferably keeping the mixture neutral
er slightly acid so that the sulphate of lime which is precipitated may be as pure as
possible. The sulphate of lime is settled, filtered, washed, dried, and otherwise
tested in known ways according to the use to which it is to be put or for which it is
to be sold

page_text: Of
A portion of the chloride of manganese formed in the reaction, but by preference
not exceeding 40 per cent. of the whole may be used, either alone or mixed with
washings from another part of the processes, for absorbing hydrochloric acid.
the remaining chloride of manganese or of the whole, from 60 to 70 per cent. is
mixed with the neutralised residuary liquor from ordinary chlorine stills together
with a suitable quantity of chloride of calcium to make a mixture fit for treatment
by the Weldon manganese-reoxidising process. Instead of using simple milk of
lime in the Weldon reoxidising process, we prefer to mix the lime after slaking in
the solution of chlorine of calcium, in which it dissolves to some extent, thereby
obtaining a thinner liquor or one with less water for a given quantity of lime and
diminishing the quantity of fuel required for concentrating solutions. Or we may
use milk of lime formed with washings from other parts of the processes. Or the
chloride of manganese may be treated by the Dunlop manganese recovery process
after having been sufficiently concentrated by heat.
The chloride of manganese not disposed of as herein before described, namely the
remaining 30 to 40 per cent is
1
70 degrees Twaddell or 1.300 to 1.350rated to a suitable density such as 60 to
specific gravity, and is run into a mixing
vessel in which it is mixed in equivalent proportions with washed mud which has
been deprived of its calcium compounds and has been obtained by the Weldon or
Dunlop recovery processes. The mixture is run into a still along with a quantity of
sulphuric acid equivalent to the chlorine present; and on applying heat all, or nearly
all the chlorine is freed and driven off, leaving sulphate of manganese in solution.
The sulphate of manganese which is nearly pure is neutralised with the washed
peroxide of manganese mud; and after settling, the clear liquor is separated and
used for mixing with chloride of calcium as herein before described.
For the operation in which chlorine is freed by suiphuric acid and driven off as
herein before described, it is necessary to have the manganese mud and chloride of
manganese as free as possible from calcium compounds and to this end the mud froi
the Weldon or Dunlop processes, is run in excess into a chlorine still along with
hydrochloric acid sufficient for the mud, together with as much more as will dissolve
all the calcium present. When the free chlorine has been driven off as in the
ordinary process the remaining contents of the still are run off and allowed to
settle; and the clear liquor is drawn off, and may be used in the manganese-reoxida-
tion part of the processes, or for being mixed with sulphate of manganese to form
sulphate of lime. In this last described way of working only a part of the chlorine
of the hydrochloric acid will be freed but the remaining part will be obtained from
the chlorides of calcium and of manganese in the manner herein before described.
By a modification of the last described way of working, and instead of running the
mud containing calcium into the chlorine still, it may be treated in or after leaving
the oxidiser with chloride of manganese liquor sufficient to convert most of the
lime into chloride of calcium. The mud after settling is run into the neutralising
well into which the residuary liquor from the stills is also run and so that the free
acid remaining in such Fquor may convert any remaining lime into chloride of
calcium.
When the clear liquor has been drawn off, the remaining mud is filtered, pressed,
and washed to render it practically free from calcium chloride. The weak washings
from the precipitated sulphate of lime and containing chloride of manganese can be
used for this purpose as they are practically free from calcium salts, with the
advantage of reducing considerably the volume of water entering the operations.
The manganese cakes obtained are, in a suitable vessel, mixed with solution of
chloride of manganese already freed from calcium chloride, and the mixture is run
into a still along with sulphuric acid as herein before described. In the still we prefer
to have the peroxide of manganese in excess rather than the sulphuric acid, so that
the residual liquid will be practically neutral. Any remaining excess of peroxide of
manganese can be separated by settling or filtering and be added to the fresh
materials for a subsequent operation.

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Impurities from the chemicals used and which will tend to accumulate in the
liquors and precipitates, are by preference removed or prevented from reaching an
injurious or objectionable quantity by periodically separating a suitable proportion of
the residual liquor of the stills in which the first portion of the chlorine is evolved,
precipitating impurities from that proportion and returning the liquor to the
remainder.
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed we declare that what
we claim is.
1. Combining chemical processes or operations for the obtainment of chlorine
and sulphate of lime substantially in the improved manner hereinbefore described.
2. In obtaining chlorine from hydrochloric acid, separating a part and forming
chloride of manganese in the ordinary way, and separating another part from chloride
of manganese by means of sulphuric acid and peroxide of manganese, the various
processes being combined substantially in the improved manner hereinbefore
described.
3. In reoxidising manganese by the Weldon process, for the obtainment of
chlorine, adding the necessary lime as dissolved or mixed in solution of chloride of
calcium substantially as herein before described.
4. In the combined series of processes for obtaining chlorine subjecting one part
of the chloride of manganese to the Weldon reoxidation process or to the Dunlop
process, and subjecting another part to distillation after, adding peroxide of
manganese and sulphuric acid substantially as herein before le-cribed.
5. In the combined series of processes for obtaining chlorine separating calcium
compounds from the manganese peroxide reconverted by the Weldon or Dunlop
processes before employing the same with sulphuric acid for obtaining chlorine
from chloride of manganese substantially as hereinbefore described.
Dated this Twenty second day of November 1889.
EDMUND HUNT,
'Applicants' Agent.