IMPROVEMENTS IN THE MANUFACTURE OF PRECIPITATED SULPHIDE OF APPLICABLE FOR USE AS A PIGMENT
Year: 1884

page_text: I, HENRY KNIGHT, of 14 Eaton Street, Liverpool in the county of Lancaster,
Paint Manufacturer, do hereby declare the nature of my said invention for
« IMPROVEMENTS IN THE MANUFACTURE OF PRECIPITATED SULPHIDE OF
APPLICABLE FOR USE AS A PIGMENT" to be as follows:-
-
ZINC
This invention relates to the manufacture of sulphide of zinc for use as a pigment,
and consists in employing a sulphur liquor prepared from waste calcium sulphides,
such as the waste product of the Leblanc soda process, by heating it with air and steam,
according to the well known Mond process (Patent 2203 of 1863) for the purpose
of precipitating zinc as a sulphide from a solution containing sulphate chloride or
other soluble salt of that metal. A solution containing sulphate chloride or acetate
of the metal is first prepared by treating metallic zinc with sulphuric hydrochloric
or acetic acid. From the solution containing one or more of these salts of zinc
impurities are removed, and this liquor then stands for further treatment.
The sulphur liquor preferably prepared according to aforesaid specification
No 2203 of 1863 is clarified by allowing it to settle, foreign matters depositing out
of it. The liquor containing the solution of zinc, and the sulphur liquor, are then
run together into suitable vessel or tank with the result of precipitating the zinc
as a sulphide. To the sulphide of zinc thus formed is added an earthy white
capable of supporting calcination without changing color, such as oxide, hydrate,
sulphate, or carbonate of lime, magnesia or baryta, natural or artificial, and the
mixture is calcined as usual. Any sulphur passing off may be collected. After
calcination the mass is drawn off into water, lixiviated, washed and dried, and is
then ready for market as a pigment.
WM P. THOMPSON & Co.,
6, Lord Street, Liverpool,
and 323, High Holborn, London,
Patent Agents for the Applicant.

page_text: I, HENRY KNIGHT of 14 Eaton Street, Liverpool, in the County of Lancaster,
Paint Manufacturer do hereby declare the nature of my said invention for
"IMPROVEMENTS IN THE MANUFACTURE OF PRECIPITATED SULPHIDE OF ZINC,
APPLICABLE FOR USE AS A PIGMENT 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 manufacture of sulphide of zine for use as a pigment
and consists in employing a sulphur liquor prepared from waste calcium sulphide
such as the waste product of the Leblanc soda process by heating it with water, air
and steam according to the well known Mond process (Patent 2203 of 1863) for
the purpose of precipitating zinc as a sulphide from a solution containing sulphate
chloride or other soluble salt of that metal.
A solution containing sulphate, chloride, or acetate of the metal is first prepared
by treating metallic zinc, pure zinc oxide or carbonate with sulphuric hydrochloric
or acetic acid, or by the precipitation of an alkaline earth, chloride, or acetate
by zinc sulphate. From the solution containing one or more of these soluble
salts of zinc the impurities are removed and this liquor then stands for further
treatment.
The sulphur liquor preferably prepared in general according to aforesaid
specification No 2203 of 1863 except that I prefer not to oxidise the waste to
quite such an extent as therein set forth, is clarified by allowing it to settle, foreign
matters depositing out of it. The liquor containing the solution of zinc and the
sulphur liquor are then run together into suitable vessel or tank, with the result of
precipitating the zinc as a sulphide. To the sulphide of zinc thus formed, is added
an earthy white, capable of supporting calcination without changing colour, such
as oxide, hydrate sulphate or carbonate of lime, magnesia, strontia or baryta,
natural or artificial, and the mixture is calcined as usual. Any sulphur passing off
may be collected. After calcination the mass is drawn off into water, lixiviated,
washed, and dried and is then ready for market as a pigment.
If I do not require lime in the mixture, I proceed as follows:-I take sulphate
of zinc and add chloride of barium, till all the sulphuric acid is taken up by the
barium and the barium is precipitated as sulphate, chloride of zinc being left in
solution. I then add the sulphur liquor which precipitates the zinc as sulphide,
chloride of calcium remaining in solution.
"
Now having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I would state that
I am well aware that the washings or drainage of alkali waste has been suggested
for this purpose, but such drainage contains much impurity and the sulphur in it
very little compared to the vast amount left in the waste, also that it has been

page_text: proposed to form a sort of artificial sulphur water by boiling lime and sulphur
together in water for several hours, but this is expensive and wasteful of sulphur, and
I make no claim for the use of either of these, but I declare that what I claim is
The manufacture of sulphide of zinc applicable for use as a pigment by pre-
cipitating the zinc from solutions of its salts by means of a sulphur liquor formed
by exposing alkali waste, or its chemical equivalent otherwise obtained to heat,
water, air and steam, substantially as described.