Year: 1885

page_text: I, JOHN BERGER SPENCE of 31 Lombard Street in the City of London Merchant
do hereby declare the nature of this invention to be as follows:-.
3
In many paints now sold, the body or base consists of sulphide of zinc, and
sulphate or carbonate of baryta, but the mode of producing these materials has
hitherto been somewhat costly and lengthy.
Now the object of this invention is to produce sulphide of zinc, and sulphate or
carbonate of baryta, in a more economical and quicker manner than heretofore.
In carrying out my invention, I dissolve metallic zinc in a caustic alkaline
solution, preferably of soda or potash, by which means I produce zincate of the
alkali employed. The dissolution of the zinc may be hastened by electrolysis.
To the zincate of the alkali I add sulphide of barium, the sulphur of which
combines with the zinc and deposits at the bottom of the vessel in the form of
sulphide of zinc. The baryta also deposits in the vessel, and to obtain the sulphate
or carbonate of baryta, I introduce sulphuric or carbonic acid, which, combining
with the baryta, forins sulphate or carbonate of baryta.
The deposit thus obtained, and consisting of sulphide of zinc and sulphate or
carbonate of baryta, is taken from the vessel, dried, and is then ready for use as
a body or base for paint.
The mode in which I proceed to obtain the carbonic acid for treating the baryta,
is to add to the liquid in the vessel, carbonate of soda or potash, according to the
nature of the alkaline solution. Chemical action takes place, and produces carbonic
acid, which is taken up by the baryta, caustic soda or potash being left, and which
goes, so to speak, to revivify the alkaline solution.
By the above mode of procedure, I am enabled to produce. the sulphide of zinc
and sulphate or carbonate of potash in a speedy and economical manner.
Dated this 18th day of November 1985

page_text: I JOHN BERGER SPENCE of 31 Lombard Street in the City of London, Merchant
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 many paints now sold, the body or base consists of sulphide of zinc and
sulphate or carbonate of baryta, but the mode of producing these materials has
hitherto been somewhat costly and lengthy.
Now the object of this invention is to produce sulphide of zinc and sulphate or
carbonate of baryta in a more economical and quicker manner than heretofore.
In carrying out my invention, I dissolve metallic zinc in a caustic alkaline
solution, preferably of soda or potash, by which means I produce a zincate of the
alkali employed.
'
In order to quicken the process, I set up an electric action in the alkaline
solution. This is conveniently effected in the following manner :-Take a suitable
vessel, preferably of iron, fill the same with a strong solution of caustic soda or of
caustic potash, and suspend therein the metallic zinc, preferably in the form of
plates. Then couple or short circuit the zinc plates with the iron vessel, and an
electric action will be immediately set up in the vessel, the result of which will be
the rapid dissolution of the zinc.
The zincate of the alkali thus produced I draw off into a suitable wooden tank
or equivalent vessel, and I add thereto sulphide of barium in such proportion as
will yield sulphur sufficient to combine with the zinc in solution and form therewith
'sulphide of zinc.
As zinc has a greater affinity for sulphur than barium, the zinc will rob the
barium of its sulphur, and will deposit on the bottom of the vessel in the form of
sulphide of zinc. A further resultant of this action is the deposit on the bottom
of the vessel, of baryta, to convert which into sulphate or carbonate of baryta,
I introduce sulphuric acid or carbonic acid, as the case may be, in suitable propor-
tions for providing the requisite equivalents of sulphur or of carbon, which,
combining with the baryta, forms sulphate or carbonate of baryta.
The mixed deposit thus obtained, and consisting of sulphide of zinc and sulphate
or carbonate of baryta, is taken from the vessel, dried, and is then ready for use
as a body or base for paint.
By the above mode of procedure, I am enabled to produce the sulphide of zinc
and sulphate or carbonate of baryta in a speedy and economical manner.

page_text: 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
In the preparation of the body or base for paints composed of sulphide of zinc
and sulphate or carbonate of baryta, the means above described for quickening
the manufacture.