Year: 1888

page_text: I, GEORGE JAMES GEARY of 2 Cumberland Street, Deansgate Manchester, in the
County of Lancaster, Merchant, do hereby declare the nature of this invention to be
as follows
-
This invention relates to the manufacture of sulphide of zinc mainly for use as a
pigment
In place of precipitating sulphide of zinc by means of sulphide of barium or other
soluble sulphide, by which (if sulphate of zinc is used) a double precipitate takes
place, or by means of sulphuretted hydrogen in a simple solution of a soluble salt of
zinc, whereby a precipitate of little body takes place, I effect the precipitation from a
solution, preferably saturated, of sulphate or chloride of zinc, and of a salt having no
chemical action on the soluble zinc salt or on sulphide of zinc and not precipitated or
altered in any way by sulphuretted hydrogen I prefer for this indifferent salt,
sulphate of potash, sulphate of soda or sulphate of magnesia
In carrying out my invention, I prefer to form the zinc solution and the other
sulphate solution each separate and add the two solutions preferably saturated, together
By this means I am enabled to exactly adjust the quantities
1 now precipitate the zinc by means of sulphuretted hydrogen and obtain thereby a
precipitate, which when dried and heated (preferably in a closed vessel) has a very
considerable body, possibly owing to the molecules of the soluble zinc salt being
separated from each other by the molecules of the indifferent salt, and consequently
they do not unite with each other to form crystals, in the way that they would do if
there were no indifferent salt separating them The liquid left after the precipitation
consists of sulphuric or hydrochloric acid and the indifferent salt By now adding
metallic zinc, oxide of zinc or carbonate of zinc to this solution the original solution is
formed to be again precipitated by sulphuretted hydrogen in its turn

page_text: The use of the in lifferent salt is also useful when other precipitants such as sulphide
of sodium or sulphide of barium are used It is also obvious that the process could
be commenced by dissolving zinc in a mixture of sulphuric acid or hydrochloric acid
(or indeed other strong acid such as icetic or nitric) and the indifferent sulphate
Dat the 10tL
T
T
1000
WM P THOMPSON & Co,
Of 6, Lord Street, Liverpool,
Patent Agents for the Applicant
Kingdom of Sweden, Gentleman
I, GEORGE JAMES GEARY of 2 Cumberland Street, Deansgate, Manchester, in the
County of Lancaster, Merchant, do hereby declare the nature of this invention and 1
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 manufacture of sulphide of zinc, mainly for use as a
pigment In place of precipitating sulphide of zinc by means of sulphide of barium
or other soluble sulphide by which (if sulphate of zinc is used) a double precipitate 2
takes place, or by means of sulphuretted hydrogen in a simple solution of a soluble
salt of zinc, whereby a precipitate of little body takes place, the precipitation is effected
from a solution, preferably saturated, of sulphate or chloride of zinc and of a salt
having no chemical action on the soluble zinc salt or on sulphide of zinc, and not
precipitated or altered in any way by sulphuretted hydrogen For this inert salt 2
(mono) sulphate of potash, of soda, of magnesia, or of ammonia is preferable
In carrying out the invention, my correspondent prefers to form the zinc solution
and the other sulphate solution each separate, and adds the two solutions, preferably
saturated, together By this means he is enabled to exactly adjust the quantities
As to the proportion of inert sulphate necessary to effect a good deposit of sulphate 3
of zinc, this varies with the sulphate used and also with the temperature and degree
of saturation of the solution, from one twelfth to nine tenths of the weight of the
solution.

page_text: The zinc is now precipitated by means of sulphuretted hydrogen, and thereby a
precipitate is obtained, which, when dried and heated, (preferably in a closed vessel)
has a very considerable body, probably owing to the molecules of the soluble zinc salt
being separated from each other by the molecules of the inert salt, and consequently,
they do not unite with each other to form crystals in the way that they would do if
there were no inert salt separating them The liquid left after the precipitation
consists of sulphuric or hydrochloric acid and the inert salt By now adding metallic
zinc, oxide of zinc, or carbonate of zinc or other ore or compound of zinc soluble
in the acid employed to this solution, the original solution is formed to be again
precipitated by sulphuretted hydrogen in its turn
The employment of the inert salt is also useful when other precipitants, such as
sulphide of sodium or sulphide of barium, are used It is also obvious that the process
could be commenced by dissolving zinc in a mixture of sulphuric acid or hydrochloric
acid (or indeed other strong acid such as acetic or nitric) and the inert sulphate
The process, as above described, can be carried on in almost any of the numerous
forms of apparatus used for treating a liquid with a soluble gas My correspondent
prefers, however, one where a mechanical agitator is used while the reaction is going
on, and where, after the latter is completed, the milky liquor is run out into a separate
tank to settle, or direct to a filter
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is
1 The process of manufacturing precipitated zinc sulphide, which consists in
adding to the zinc solution a solution of monosulphate of Potash of soda of Ammonia
or of Magnesia or other inert salt such as described, or forming a mixed solution of a
zinc salt and of an inert salt such as described, and then precipitating the zino by
sulphuretted hydrogen or other sulphide
2 When sulphuretted hydrogen has been used in the manner described, utilising
the mother liquor of the above operation to dissolve fresh quantities of zinc, and con-
tinuing the operation, substantially as described
D THOMPSON Ra