A Process for the Manufacture of Lead Sulphite for use as a White Lead Pigment.
Year: 1896

page_text: Date of Application, 8th Sept., 1890
Complete Specification Left, 19th May, 1897-Accepted, 14th Aug., 1897
Date of
oth dept., 1990
Complete Specification Left, 19th May, 1897-Accepted, 14th Aug., 1897
PROVISIONAL SPECIFICATION.
A Process for the Manufacture of Lead Sulphite for use as a White
Lead Pigment.
I, ANDREW CHARLES JOSEPH CHARLIER of 107 Breadalbane Terrace, Hill Street, in
the County of the City of Glasgow, North Britain, Chemist do hereby declare the
nature of this invention to be as follows:-
This invention relates to the conversion of oxide of lead into neutral or basic
sulphites of lead.
White lead as known to the trade consists of hydrate of lead, carbonate of lead or
sulphate of lead but by this process a sulphite is, under certain conditions mentioned
below, formed into a white lead which whilst being non-poisonous contains more
covering power and body as a pigment than any other white lead at present
manufactured.
Several covered vats are arranged in a series fitted with agitators. Into these finely
ground oxide of lead is placed after being mixed into a paste with water which may
or may not be slightly acidified according to the quality of the oxide of lead employed
in the manufacture of the white lead. In connection with these vats is a furnace
for burning sulphur or other compound of sulphur which will produce sulphur
dioxide. An air pump is connected with the furnace which whilst supplying the
proper volume of air for the formation of sulphur dioxide also forces the gas from
the furnace through a washer after which it passes through into the vats containing
the oxide of lead and given certain conditions of temperature which is regulated by
means of steam coils inside the vats the sulphur dioxide immediately attacks the
oxide of lead and forms sulphite of lead which is then simply pressed and dried and
is ready for the market to be sold as white lead.
The essential feature of my invention is therefore the use of sulphur dioxide in a
gaseous state for the conversion of oxide of lead into sulphite of lead and thus
producing white lead suitable for use as a pigment.
Dated this 7th day of September 1896.
113 ncent Street, omsgow, retitione S Agents.
COMPLETE SPECIFICATION
0 A Process for the Manufacture of Lead Sulphite for use as a White
Lead Pigment.
I, ANDREW CHARLES JOSEPH CHARLIER of 107, Breadalbane Terrace, Hill Street, in
the County of the City of Glasgow North Britain, Chemist, do hereby declare the
0 A Process for the Manufacture of Lead Sulphite for use as a White
Lead Pigment.
I, ANDREW CHARLES JOSEPH CHARLIER of 107, Breadalbane Terrace, Hill Street, in
the County of the City of Glasgow North Britain, Chemist, do hereby declare the

page_text: 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 :-
This invention relates to the conversion of oxide of lead into neutral or basic
sulphite of lead thus forming white lead suitable for use as a pigment.
White lead as known to the trade consists of hydrate of lead, carbonate of lead or
sulphate of lead but by this process a sulphite is under certain conditions mentioned
below formed into a white lead which whilst being non-poisonous contains more
covering power and body as a pigment than any other white lead at present
manufactured.
The whole apparatus, which must be completely air tight, consists of several
covered vats arranged in a series fitted when necessary with agitators and also steam
coils. Into these vats finely ground oxide of lead is placed after being mixed into a
paste with water which may or may not be slightly acidified according to the quality
of the oxide of lead employed in the manufacture of the white sulphite of lead.
In connection with the vats is a furnace for burning sulphur or other compounds
of sulphur which will produce, when burning in conjunction with air, sulphur
dioxide gas.
An air pump is connected with the furnace which keeps it continuously supplied
with the requisite amount of air necessary for the burning sulphur to combine with
the oxygen of the air and form SO, or sulphur dioxide gas.
The gas is then passed through a washer to free it from all impurities and the pure
gas then passes through the vats containing the oxide of lead and thus converting
PbO into PbSO, or sulphite of lead.
The whole apparatus is worked under a pressure of 10 to 20 lbs. to the square inch
and given the proper degree of temperature which may be obtained by the use of
steam coils in the converting vats and given also the sulphur dioxide gas, is washed
free from all impurities before acting upon the oxide of lead, it is easily converted
into sulphite of lead which may be neutral or basic according to the quantity of
sulphur dioxide passed into the lead and the resulting compound forms a white lead
suitable for use as a pigment.
When I get the basic sulphite of lead it may be neutralised with acids preferably
such acids as themselves give precipitates of white lead in neutralisation thus
PbSO, PbO + H₂SO = PbS0, x PbS0.
My principal claim is the use of Sulphur Dioxide gas for the conversion of
PbO into PbSO, another combination may however be obtained by the use of a gas
containing a mixture of Sulphur Dioxide and carbon Dioxide which will produce a
white lead consisting of carbonate and sulphite of lead.
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:-
1st. The use of sulphur dioxide in a gaseous state for the conversion of oxide of
lead into a suphite of lead and thus producing white lead suitable for use as a
pigment.
2nd. The use of preferably sulphuric acid or any other acid which will produce
white lead from oxide of lead and which can be used to neutralise the basic white
lead into the neutral state.
3rd. The combined use of sulphur dioxide gas with carbon dioxide gas for the
conversion of lead oxide into a mixture of sulphite and carbonate of lead and thus
also producing a white lead suitable for use as a pigment.
Dated this 10th day
JOHNSONS,
115, St. Vincent Street, Glasgow, Applicant's Agents.