Improved Manufacture of Vermilion.
Year: 1892

page_text: Date of Application, 15th Mar., 1892
Complete Specification Left, 15th Dec., 1892-Accepted, 18th Feb., 1893
PROVISIONAL SPECIFICATION.
Improved Manufacture of Vermilion.
We, HAROLD WILLIAMS PICTON, B.Sc., Chemist, of 80 Regents Park Road,
in the County of Middlesex, and SAMUEL ERNEST LINDER, B.Sc., Chemist, of
Oakfield, Buckhurst Hill, in the County of Essex, do hereby declare the nature of
this invention to be as follows :-
The method of obtaining vermilion by the wet process most generally adopted
consists in heating black sulphide of mercury (HgS) with an alkaline sulphide
such as potassium or ammonium sulphide. The objection to this method is the
great difficulty that is experienced in getting rid of the last portions of the alkaline
sulphides on account of the free sulphur clinging to the vermilion. The presence
of these impurities much impairs the value of the vermilion as a pigment and the
object of our invention is to do away with the necessity of employing an alkaline
sulphide in the preparation of vermilion.
•
For this purpose we first precipitate sulphide of mercury in any convenient
manner such, for instance, as by passing sulphuretted hydrogen gas through a
solution of mercuric salt. The black precipitate is then filtered off and washed
with water; the precipitate is then suspended in water and saturated with
sulphuretted hydrogen gas, the black sulphide dissolves and on keeping a strong
solution heated at a suitable temperature for several hours it slowly and spon-
taneously changes into vermilion.
We have found that the re-action proceeds more rapidly when the solution is
heated in a closed vessel at a fairly high temperature say from 160 to 170° C.
Dated this 15th day of March 1892,
W. P. THOMPSON & BOULT,
Agents for the Applicants.
COMPLETE SPECIFICATION.
Improved Manufacture of Vermilion.
We, HAROLD WILLIAMS PICTON, B.Sc., Chemist, of 80 Regents Park Road,
in the County of Middlesex, and SAMUEL ERNEST LINDER, B.Sc., Chemist of
Oakfield, Buckhurst Hill, in the County of Essex, 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 :-
The method of obtaining vermilion by the wet process most generally adopted
consists in heating black sulphide of mercury (HgS) with an alkaline sulphide
such as potassium or ammonium sulphide. The objection to this method is the
great difficulty that is experienced in getting rid of the last portions of the alkaline
sulphides on account of the free sulphur clinging to the vermilion. The presence
of these impurities much impairs the value of the vermilion as a pigment and the
object of our invention is to do away with the necessity of employing an alkaline
sulphide in the preparation of vermilion.
For this purpose we first precipitate sulphide of mercury in any convenient
manner such for instance as by passing sulphuretted hydrogen gas through a
solution of mercuric salt. The black precipitate is then filtered off and washed
with water; the precipitate is then suspended in water and saturated with
sulphuretted hydrogen gas, the black sulphide dissolves and on keeping a strong
solution heated at a suitable temperature, say about 170° C., for several hours it
slowly and spontaneously changes into vermilion.

page_text: We have found that the re-action proceeds more rapidly when the solution is
heated in a closed vessel at a fairly high temperature. say from 160 to 170° C.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
"
In the manufacture of vermilion the improved treatment of the black sulphide of
mercury consisting in first precipitating and then suspending it in water saturated
with sulphuretted hydrogen gas, thereby dissolving the sulphide, which is finally
heated for several hours till it changes into vermilion, substantially as specified.
Dated this 14th day of December 1892.
HAROLD WILLIAMS PICTON.
SAMUEL ERNEST LINDER.
W. P. Thompson & Boult,
Agents for the Applicants.