Improvements in Apparatus for Oxidising Lead Sulphide and Zinc to Form White Pigments.
Year: 1891

page_text: Date of Application, 23rd Sept., 1891
Complete Specification Left. 22nd June, 1892-Accepted, 27th Aug., 1892
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Oxidising Lead Sulphide and Zinc
to Form White Pigments.
We, FREDERICK JOHN ROWAN, of 121, West Regent Street, Glasgow, in the
County of Lanark, North Britain, Engineer, and BERNARD DAWSON, of York
House, Malvern Link, in the County of Worcester, Engineer, do hereby declare
the nature of this invention to be as follows, that is to say :-
Our
This invention has for its object the making of white pigments of superior quality,
by oxidising lead sulphide and zinc in an improved and economical manner.
invention comprises various modifications of apparatus and details; but in all cases
the arrangements are such as to avoid as much as possible the admixture with the
products, of carbonaceous or other foreign particles of kinds to diminish the purity
of the pigments. With our improved apparatus less fuel will be required than
heretofore.
For the manufacture of the lead pigment we may employ galena or any suitable
lead sulphide or a lead ore or compound supplemented with more or less sulphur or
sulphur-yielding material; and for the zinc pigment zinc or any suitable ore or
compound of zinc may be employed.
In carrying out our invention according to one modification we employ a
regenerative gas furnace having a reverberatory chamber, across which are placed
a series of retorts. Into one end of each retort the material to be operated on is
in a pulverised state injected, by means of a jet of air or steam; or the material
may be fed into the retort by any suitable known mechanism such as a rotating
screw or paddle, or a pair of rollers, or a reciprocating shovel, a jet of air being
admitted at the same time. The retorts are inclined so that any slag from the
material may flow to one end, the charging or injecting end being preferred when
convenient. In the heated retorts when the material is galena or lead sulphide it
is oxidised to lead sulphate, and being converted into a fume passes on from the
further ends of the retorts into flues and cooling chambers or passages, and into any
suitable collecting apparatus, wet fume condensers being by preference employed,
and steam or air jets being applied to propel the fume into the condenser, and to
facilitate its withdrawal from the retorts. In a similar way if the material is zinc
it is oxidised and passes from the retorts as a fume.
According to a second modification a gas furnace is employed but is arranged as
what is known as a blow-pipe furnace. The combustible gas used, and which is
made as free as practically possible from carbonaceous and dust particles is injected
into the furnace chamber through a nozzle which is encircled by an annular jet
orifice or an annular series of orifices through which the air for combustion is
injected. The pulverised galena or other material is by preference fed in through
a central pipe or nozzle extending into the gas nozzle. The furnace chamber may
be formed in a stationary structure, or it may be the interior of a rotating cylinder
which latter by turning over the materials will ensure their exhaustion. The
chamber is inclined so that any slag may flow to one end; and when the end further
from the feeding-in end is made the lower one, there is provided a discharge opening
through which the slag drops into a truck, but which is arranged in a manner to
prevent escape of the fumes.
In any of the modifications the galena or other material operated on may be
subjected to a preparatory heating before being injected into the main furnace."
Dated this Twenty-second day of September 1891.

page_text: COMPLETE SPECIFICATION.
Improvements in Apparatus for Oxidising Lead Sulphide and Zinc
to Form White Pigments.
いやい
We, FREDERICK JOHN ROWAN, of 121 West Regent Street, Glasgow, in the
County of Lanark, North Britain, Engineer, and BERNARD DAWSON, of York
House, Malvern Link, in the County of Worcester, Engineer, 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, that is
to say:
Our
This invention has for its object the making of white pigments of superior quality,
by oxidising lead sulphide and zinc in an improved and economical manner.
invention comprises various modifications of apparatus and details, but in all cases
the arrangements are such as to avoid as much as possible the admixture with the
products of carbonaceous or other foreign particles of kinds to diminish the purity
of the pigments. With our improved apparatus less fuel will be required than
heretofore.
For the manufacture of the lead pigment we may employ galena or any suitable
lead sulphide or a lead ore or compound supplemented with more or less sulphur or
sulphur-yielding material; and for the zinc pigment zinc or any suitable ore or
compound of zinc may be employed.
We operate with improved apparatus of which examples are shown on two
accompanying sheets of explanatory drawings.
In carrying out our invention according to one modification we employ apparatus
of the kind shown on Sheet, 1, of the drawings,
Figure, 1, being a longitudinal vertical section, and Figure, 2, a plan.
Figure, 3, is a transverse vertical section corresponding to Figures, 1, and 2; and
Figure, 4, is a similar section but showing a variation of certain parts.
The apparatus comprises a regenerative gas furnace with the usual regenerative
chambers, A, and having a reverberatory chamber, B, across which are placed a
series of retorts or muffles, C, constructed preferably of fire-brick. Into one end
of each retort, C, the material to be operated on is, in a pulverised state, injected
by means of a jet of air, or steam or oxygen, directed into the retort by a nozzle, D,
connected to a supply pipe. Or the material may be fed into the retort by any
suitable known mechanisin, such as a rotating screw or paddle, or a pair of rollers,
or a reciprocating shovel, a jet of air being admitted at the same time. In the
modification shown in Figures, 1, 2, and 3, each retort, C, has at its feeding end a
hopper, E, and the several hoppers receive the material from a horizontal duct, F,
extending over the series of hoppers and having in it a rotating screw which moves
the materials along it. The jet nozzle, D, for injecting the material into each
retort is arranged in a funnel-shaped inlet fixed to the lower part of the hopper, E.
In Figure, 4, a reciprocating shovel, H, is shown for throwing the material into
the retort; and in this case the air required for oxidising is injected through a
nozzle, D, the jet passing through a hole in the shovel, H.
The retorts, C, are inclined so that any slag from the material may flow to one
end, the charging or injecting end, as shown, being preferred when convenient; and
a discharge duct, W, is provided for withdrawing the slag into a truck, X. In the
heated retorts, when the material is galena or lead sulphide, it is oxidised to lead
sulphate, and being converted into a fume passes on from the further ends, J, of
the retorts, C, into flues and cooling chambers or passages, K, and into any suitable
collecting apparatus, wet fune condensers being by preference employed, and steam
or air jets being applied to propel the fume into the condenser, and to facilitate its
withdrawal from the retorts. In a similar way if the material is zinc it is oxidised
and passes from the retorts as a fume.
The galena or other material operated on may be subjected to a preparatory
heating before being injected into the retorts or furnace. For effecting such
COM

page_text: preparatory heating operation there may be employed a small gas-heated rever-
beratory furnace, L, such as is shown in Figures, 1, 2, and 3. This furnace, L, is
represented as supported on pillars, M, at a height suitable for conveniently trans-
ferring the heated materials from it into a hopper, N, at one end of the duct, F,
from which the hoppers, E, of the several retorts, C, receive their supplies. The
furnace, L, is connected by branch flues with gas and air ducts. The various
reversing valves and other parts may be of ordinary construction and arrangement
and do not require to be particularly described. Or the material may be
preparatorily heated to some extent by being placed for a time in an oven, Z, as
shown in Figure, 4, constructed above the main furnace, B.
According to a second modification a gas furnace is employed but is arranged as
what is known as a blow-pipe furnace.
'
Figure, 5, Sheet, 2, is a longitudinal vertical section of such a furnace as
constructed for carrying out our invention.
Figure, 6, is a transverse vertical section as through the vertical gas supply pipe
and other parts; and
Figure, 7, is a transverse vertical section as through the burner.
The combustible gas used, and which is made as free as is practically possible
from carbonaceous and dust particles, is supplied by a vertical flue, P, at the higher
end of an inclined rotating cylindrical furnace, Q, which is constructed of iron or
steel lined with firebrick or other refractory material. The gas is injected into
the furnace chamber, Q, through an annular series of passages, R, in a nozzle piece
these passages encircling a central passage, S, through which the material to be
oxidised is fed in. The nozzle passages, R, for gas are encircled by an annular
series of passages or orifices, T, through which the air for combustion and oxidation
is injected, these orifices, T, being formed in an iron casing supplied with compressed
air by a pipe, U. Or the shaft of the feeding screw, V, might be made tubular and
the air be injected through it.
The material to be oxidised is fed through the central passage, S, by a rotating
screw, V, from a hopper, E, supplied from a duct, F, and other parts as in the first
modification. The oxidised fume passes off from the lower end of the furnace, Q,
into flues or passages, K; whilst close to the retort there is a funnel-shaped
outlet, W, for slag, the form given to it being such as to prevent any appreciable
leakage of fume. The slag may drop from the outlet, W, into a truck, X, placed
in a chamber which is closed to prevent the escape of fumes.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is :-
1. In apparatus for oxidising lead sulphide and zinc the combination of a
regenerative gas-fired furnace, retorts in the reverberatory chamber of the furnace,
means for injecting the material to be oxidised and air into the retort, the said
material being in a pulverised state and preparatorily heated or not heated, and
flues and outlets for the fume produced and for slag, the parts being constructed
arranged and operating substantially as herein before described.
2. In apparatus for oxidising lead sulphide and zinc the combination of a rotating
or non-rotating gas-fired furnace chamber, a compound "blow-pipe" nozzle having
a central inlet passage for the material to be oxidised, encircled by gas orifices and
outside of these by air orifices, means for supplying the material in a pulverised
state and preparatorily beated or not heated, and flues and outlets for the fume
produced and for slag, the parts being constructed arranged and operating sub-
tantially as herein before described.
Dated this Twenty-first day of June 1892.
EDMUND HUNT,
Applicants' Agent.