IMPROVEMENTS IN THE MANUFACTURE OF ZINC PIGMENTS
Year: 1879

page_text: LETTERS PATENT to Edward William Parnell, of Liverpool, in the County
of Lancaster, Manufacturing Chemist, for the Invention of "IMPROVEMENTS
IN THE MANUFACTURE OF ZINC PIGMENTS."
Sealed the 5th August 1879, and dated the 12th February 1879.
PROVISIONAL SPECIFICATION left by the said Edward William Parnell
at the Office of the Commissioners of Patents on the 12th February 1879.
EDWARD WILLIAM PARNELL, of Liverpool, in the County of Lancaster, Manufac-
turing Chemist. "IMPROVEMENTS IN THE MANUFACTURE OF ZINC PIGMENTS."
The object of my Invention is to produce sulphuret of zinc in a fine state of divi-
sion and of a high degree of purity.
J
For this purpose I employ two solutions, one a solution of metallic zinc or zinc
oxide in caustic alkali or caustic alkaline solution; and the other an alkaline sul-
phuret solution. Employing two such solutions admits of easily purifying each
solution separately, so as to ensure that when the said two solutions are mixed
together in the proper proportions pure or nearly pure zinc sulphuret will be formed
as a precipitate and pure or nearly pure caustic alkali will be left in the liquid form.
The said caustic alkali may be used again in the manufacture of zinc sulphuret or
otherwise used. After washing and drying the precipitated sulphuret of zinc is
ready for use as a pigment.
When a caustic alkali or caustic alkaline solution is used it is by preference sub-
jected to heat and agitation whilst the metallic zinc or zinc oxide is being dissolved
therein. The alkaline sulphuret solution may be prepared in any desired manner.
Before use the alkaline zinc solution should be purified by the addition thereto
of a small quantity of an alkaline sulphuret or suitable sulphur compound to preci-
pitate impurities, and the alkaline sulphuret solution should be purified by the
addition thereto of a small quantity of the alkaline zinc solution. In the latter
case zinc sulphuret formed carries down any impurities contained in the alkaline
sulphuret solution that would interfere with the quality of the finished article.

page_text: SPECIFICATION in pursuance of the conditions_of_the_Letters Patent nied
by the said Edward William Parnell in the Great Seal Patent Office on the
12th August 1879.
-
EDWARD-WILLIAM PARNELL,- of-Liverpool, in the County of Lancaster, Manufac-
turing Chemist. "IMPROVEMENTS IN THE MANUFACTURE OF ZINC PIGMENTS:"
The object of my Invention is.to produce sulphuret.of zinc.in.a.fine.state.of_divi-
sion and of a high degree of purity.
For this purpose I employ two solutions, one a solution of metallic zinc or zinc
oxide in caustic alkali or caustic alkaline solution, and the other an alkaline sul-
phuret solution, such as sulphuret of soda or potassa. Employing two such solutions
admits of easily purifying each solution separately, so as to ensure that when the
said two solutions are mixed together in the proper proportions, preferably so that
the supernatant liquor shall contain a small excess of the alkaline zinc solution,
pure or nearly pure zinc sulphuret will be formed as a precipitate, and pure or
nearly pure caustic alkali will be left in the liquid form. The said caustic alkali
After
may be used again in the manufacture of zinc sulphuret, or otherwise used.
washing and drying, the precipitated sulphuret of zinc is ready for use as a
pigment.
When a caustic alkali or caustic alkaline solution is used it is by preference sub-
jected to heat and agitation whilst the metallic zine or zinc oxide is being dissolved
therein. The alkaline sulphuret solution may be prepared in any desired manner.
Before use the alkaline zinc solution should be purified by the addition thereto of a
small quantity of an alkaline sulphuret or suitable sulphur compound to precipitate
impurities, and the alkaline sulphuret solution should be purified by the addition
thereto of a small quantity of the alkaline zine solution. In the latter case the zinc
sulphuret formed carries down any impurities contained in the alkaline sulphuret
solution that would interfere with the quality of the finished article.
The manufacture of zinc pigment substantially as above described may be advan-
tageously carried on in connection with the manufacture of alkalies by the Leblanc
process, in which process the crude solutions of alkali are invariably contaminated
with sulphurets. The said sulphurets may be used in place of the alkaline sul-
phurets above mentioned, whereby the production of the zinc sulphuret is cheapened
and pure alkali obtained at diminished cost.
If found desirable to manufacture increased quantities of sulphuret of zinc, the
Leblanc process may be so carried on that the amount of sulphurets in the crude
alkali shall be augmented.
Having now described the nature of the said Invention in such manner that
others will be enabled to carry my improvements into effect, I claim,-
The improvements in the manufacture of zinc pigment or sulphuret, substantially
as herein set forth.
In witness whereof, I, the said Edward William Parnell, have hereunto set
my hand and seal, this Eleventh day of August, in the year of our Lord
One thousand eight hundred and seventy-nine.