IMPROVEMENTS IN AND IN APPARATUS FOR THE MANUFACTURE OF LEAD SALTS FOR MAKING WHITE LEAD
Year: 1884

page_text: I WILLIAM VIRGO WILSON of Jubilee Street, Mile End in the County of
Middlesex, Colour Manufacturer do hereby declare the nature of my invention
for IMPROVEMENTS IN AND IN APPARATUS FOR THE MANUFACTURE OF LEAD
SALTS FOR MAKING WHITE LEAD to be as follows:-
This invention has for its object the facilitation of the solution of finely divided
metallic lead by digestion with Acetic or Nitric Acids or neutral Acetate or nitrate
of Lead and is effected in the following manner-
By preference I employ a cylindrical vessel made to revolve slowly on its own
axis and suspended from hollow trunions one for the inlet and the other for the
outlet of air, steam &c, during the time of its rotation.
This cylinder is provided on its internal circumference with vanes or shelves
which in the course of the revolution of the cylinder carry the lead upwards so
bringing it into contact with the atmospheric air lying above the level of the
liquid.
From these shelves as shown by the accompanying sketch, the lead drops on to
another set attached to the hollow axis of the machine, thus giving a longer time
for its oxidation, & subsequently is dropped again into the liquid when the lead
oxide formed is at once taken up.
This operation is continued until the solution is sufficiently saturated for
subsequent precipitation by Carbonic Acid Gas.
For the purpose of raising the temperature of the contents of the Cylinder
I employ hot air or steam superheated or otherwise.
The object being to supply atmospheric air as it may have been absorbed by the
Lead, this can be attained by an induced current by aspiration or dragged in by
steam or otherwise forced in by any well known mechanical means.
Price A71

page_text: DESCRIPTION OF DRAWING,
A. Shelves attached to the internal wall of Cylinder.
B Shelves attached to the central hollow Box C.
O Hollow Box perforated all over with small holes for the passage of air, stear
& liquor.
D Diaphram to prevent the direct exhaust of air & steam.
El Air, steam & liquor supply pipe & its conical attachments to I.
E 2. Air & steam exhaust
ditto
G. Manhole for the supply of metallic lead.
H Liquor exhaust valve.
ditto
T1 & 2 Hallow minions bored conical at outer ende
ditto.

page_text: I WILLIAM VIRGO WILSON, of Jubilee Street, Mile End, in the County of
Middlesex, Color Manufacturer do hereby declare the nature of my invention for
IMPROVEMENTS IN AND IN APPARATUS FOR THE MANUFACTURE OF LEAD SALTS
FOR MAKING WHITE LEAD and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement :-
This Invention has for its object to facilitate the solution of finely divided
metallic lead by digestion in a solution of neutral acetate or nitrate of lead, and it
consists in an apparatus whereby the lead is alternately exposed to a current of
air (by which the lead becomes oxidised) and immersed in the liquor by which the
lead oxide formed is dissolved.
Reference is to be had to the accompanying drawings forming part of this
Specification in which figure 1 is a cross section and figure 2 a longitudinal section
of the apparatus taken on line 1. 1. fig 1.
The apparatus consists of a drum A revolving on a horizontal axis, and provided
with an outer set of inwardly projecting vanes or shelves B fixed at suitable.
intervals around its internal circumference, and with a second or inner set of
vanes C so arranged with respect to the circumferential set as to catch the lead
raised by the latter on its falling therefrom and prevent it falling back immediately
into the liquid in order that it may be exposed a longer time to the oxidising
action of the air. With this second set of vanes or shelves is combined a central
perforated trunk or box D, by which the liquor raised with the lead is strained
therefrom and the passage of air or air and steam through the drum is permitted.
Thus by transferring the lead from one set of vanes to the other it is freed from
the liquor raised with it and thoroughly exposed to the air.
The drum A is mounted to revolve on hollow gudgeons a¹ a mounted in
suitable standards and respectively in connection with the inlet and outlet pipes E¹
and E, the joint between the outer ends of the gudgeons and the pipes being coned
or otherwise made sufficiently tight. The gudgeons communicate with the interior
of the trunk D, the direct communication with the opposite ends thereof being
intercepted by a diaphragm F in order to cause the air or air and steam to take
the course indicated by the arrows the sides of the trunk being perforated all over
with holes d (of which a few only are shown) of a such a size (say 1/10th in diameter)
as not to allow the metallic lead to fall through into the trunk.
The drum A is preferably constructed of wood lined or covered internally with
sheet tin.
It is caused to revolve slowly by worm gear or other means, and in the course
of its revolution the metallic lead is raised out of the liquid (which fills less than
half the drum) and on falling from the vanes B is caught by the vanes C and by
them carried over the centre, after which the oxidised lead is dropped back into
the liquid by which the lead oxide formed is at once taken up, this alternate action
being continued until the solution is sufficiently saturated with lead oxide for
subsequent precipitation with carbonic acid gas in another vessel.
In order to raise the temperature of the solution and supply oxygen as fast as it
is absorbed by the lead, hot air is forced in, or a current of air induced by a jet of
steam superheated or otherwise.
G is the manhole for the introduction of the metallic lead and H the outlet for
the liquor.

page_text: Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I would observe that
I do not limit my invention to the particular number and arrangement of the vanes
or to the construction of the drum and the trunk herein shown but what I claim is
1st An apparatus for facilitating the solution of metallic lead by alternately
exposing it to the air and immersing it in a solvent for lead oxide, consisting of a
revolving druin provided with outer and inner sets of internal vanes the inner
set being so arranged with respect to the outer set as to catch the lead raised by
and falling from the outer set and carry it over the axis of revolution of the drum,
substantially as specified.
2nd An apparatus, for the purpose herein specified, consisting of a revolving
drum provided with inner and outer sets of internal vanes, in combination with a
central trunk perforated for the passage of air and liquid and with an axial inlet
and outlet for the air, substantially as shown and described.
3rd The method herein described of effecting the solution of finely divided
metallic lead by its alternate exposure to air and immersion in a solvent for oxide
of lead, which method consists in carrying the lead round in a revolving druin
containing the solvent and provided with sets of vanes by which the lead is raised
and detained out of the solvent and which is traversed by a current of hot air or a
jet of air and steam as specified.