to Apparatus therefor.
Year: 1888

page_text: to Apparatus therefor.
I, JOHN WESLEY HALL, of the firm of John Hall & Sons, Glass Merchants,
51 Broadmead, in the City and County of Bristol, 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:
Heretofore the manufacture of lead pigment from galena has been carried on in
the manner set forth in the specifications of former Letters Patent granted to the said
George T. Lewis and to E. O. Bartlett, either separately or jointly, that is to say, by
directly subliming galena ore, the galena being thrown upon a hot fire by a blast of
air, which is forced into the mass of ore and fuel, or by blowing powdered galena ore
into red hot retorts. It has also been made by refining the waste fumes and flue-dust
of lead-smelting furnaces.
In all these cases, a solid fuel has been used, and its use has been found in some
respects disadvantageous, the mineral impurities of the coal (ashes) and the irregu-
larity in feeding being liable to cause discolouration of the pigment; moreover the
silicious ashes cause a loss of lead, a portion of the lead being thrown into the slag.
The use of retorts has also been found disadvantageous on account of their great
expense. By my present invention I am enabled to obviate all these objections.
According to my improved method or process, powdered galena ore is intimately
mixed with natural or generated gas or liquid hydrocarbon, and this admixture is
burned in a combustion chamber. The galena will be completely oxidized; and in
this form is carried off by an exhaust and forced into receptacles of textile fabric
where it is collected.
In the accompanying drawing I have shown apparatus in which my method or
process can be conveniently and advantageously carried on.

page_text: A is a hopper into which the powdered ore is placed. This hopper has an outlet a
across which a blast of air is to be blown by means of a pipe B. C is a channel for
the introduction of gas. D is a reverberatory-shaped combustion-chamber. E a
settling chamber at the lower end of which is a hopper F. G is a fan. H, H are
cooling pipes. J is a pipe for conducting oxidized galena into the receptacles K of
textile fabric.
The gas is caused to enter through the channel C, and, at the point b, the gas is
mixed with the finely divided ore blown by the blast. The finely-divided ore mixed
with the gas and air are blown through the chamber D, which is preferably lined
with basic material. In this chamber the gas is ignited, by which means the lead ore
is oxidized. Any coarse galena falls to the bottom of this chamber and is removed.
The oxidized ore is carried into the settling chamber E. Any coarse material or
heavy particles fall into the hopper F and are removed. The fan G draws the finely
divided particles of oxidized ore from the igniting or combustion-chamber through
the settling-chamber E and through the cooling-pipes H, and drives them through the
pipe J into the bags K of textile fabric, where the oxidized ore is deposited.
Any liquid hydrocarbon can be used in place of the gas, and when it is used, I
dispense with the gas-channel C and mix or saturate the finely divided ore to be
heated, with the liquid hydrocarbon in the hopper A, and the finely divided ore so
saturated is blown into the chamber D where the hydrocarbon is ignited and the
operation continues in the manner herein before described. By this admixture of air,
gas, or liquid hydrocarbon and pulverized ore prior to their introduction into the
combustion-chamber, I am enabled to cause the air and gas or liquid hydrocarbon to
become so intimately mixed with each other prior to combustion that, when
combustion commences, its effect on the ore is more perfect and rapid on account
of the close connection of the ore and gas or liquid hydrocarbon with each
other.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me
by my foreign correspondent I wish it understood that I do not claim broadly the
use of gas as a fuel in the manufacture of lead-pigments, but I claim ;-
The process of manufacturing sublimed lead-pigment from finely divided galena,
consisting in forming a compound current of intimately admixed gas or liquid
hydrocarbon, air and finely divided galona, introducing the said current into a
combustion-chamber and inflaming it at the entrance thereof, maintaining the
resultant salts in suspension by the air-blast while being forced through the said
chamber, cooling the material obtained by the combustion of the gas and galena, and
depositing the lead salts by forcing thom into receptacles of textile fabric, substantially
as set forth.
1
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London,
Agents for the Applicant.