Improvements in Obtaining Alkaline Salts from Blast Furnace or other Gases, and Apparatus therefor.
Year: 1896

page_text: Date of Application, 28th Feb., 1896
Complete Specification Left, 28th Nov., 1896-Accepted, 27th Feb., 1897
Improvements in Obtaining Alkaline Salts from Blast Furnace or
other Gases, and Apparatus therefor.
I GEORGE CRAIG of Lugar Iron Works, Cumnock, Ayrshire, Scotland, Chemist
do hereby declare the nature of this invention to be as follows:-
Coal and coke contains more or less alkalies potash and soda. In blast furnaces
wherein large quantities are consumed under certain conditions these alkalies
accumulate in the lower parts, and if the gas is blown or drawn off thereat, it is
found to be highly charged with alkaline salts: chiefly cyanides and carbonates of
potash and soda vapourised. Similar results ensue in operations in which coal or coke
is burned in an analogous way, with or without addition of alkali for the production of
cyanides. To obtain these salts economically 1 prefer to have suitable openings in the
furnace connecting directly with a suitable vessel (which may be cooled if necessary)
in which any liquid or ejected material may lodge and the gas become cooled. The
gas loaded with alkaline salts flows along a pipe furnished with mechanical cleaning
appliances (consisting of a spiral or other suitable conveyor) to the filtering chambers
in which the bulk of the alkaline salts is recovered. The filtering material may be
the alkaline salts deposited in the leading pipes after being conveyed on to or between
wire-gauze, asbestos or other suitable support in the filtering chamber. Said layer
may be horizontal or vertical or otherwise.
Dated this 27th day of February 1896.
D. F. MASON,
Glasgow, Patent Agent.
Improvements in Obtaining Alkaline Salts from Blast Furnace or
other Gases, and Apparatus therefor.
I, GEORGE CRAIG formerly of Lugar Iron Works, Cumnock, Ayrshire, but now of
No. 57 Hope Street, Glasgow, Scotland, Chemist, 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:—
My said invention has for its object to recover or obtain alkaline salts from blast
or other furnace gases.
Coal, coke and certain other carbonaceous materials contain more or less alkalies
potash and soda. In blast furnaces where large quantities of aforesaid material are
consumed these alkalies accumulate in the lower regions of the furnace and if gas
is blown or drawn off thereat it will be found to be highly charged with vapourised
alkaline salts, chiefly cyanides and carbonates.
Similar results ensue in operations in which coal or coke is burned in an analogous
way with or without the addition of alkali for the production of cyanides.

page_text: To obtain these alkaline salts economically have devised the machinery or
apparatus illustrated in the accompanying two sheets of drawings, in which,
Figure 1 illustrates part of the lower part of binst furnace with the cooling trap in
elevation, the conveyor in part longitudinal section, and the filtering apparatus in
vertical section on the line 6. 7 of Fig. 5 which is a sectional plan of said filter,
Fig. 3. being a vertical section of same on the line 8. 9. Fig. 5.
Fig. 4, is a plan of the filter scraper.
Similar reference letters refer to similar parts throughout the several views.
are open from
As applied to a blast furnace A as shown at Fig. 1. I prefer to have an opening
or openings located in the lower regions of the furnace at & communicating directly
with a metal cooling trap e which may be cooled by water or otherwise if necessary,
and in which any liquid or solid ejected matter from the furnace lodges, and which
may be cleaned out when required by doors (not shewn). The trap c has an opening
at bottom into the pipe or case having a shaft p' on which is a spiral conveyor 9
which conveys the solid matters deposited thereabout to the opening into the filter
chamber. The shaft g' is revolved by worm wheel K, wrought by a worm driven
by any suitable motor engine m. The outer filter chamber i may conveniently be
built up of iron plates into an outer square case having flanges n on its inner sides,
and cross T iron beams from side to side Figs. 3 & 5, which support bed plates o
each constituting the hottom or longitudinal partition of the separate inner chambers
or compartments into which the main chamber may be dividel. Iron beams from
sile to side a little above level of partition plates support a sieve forming
as it were a false bottom in its chambers preferably of wire gauze (but which may be
of any other suitable material) to support the layer of alkaline salts constituting the
filtering medium.. Both left hand corners p. Fig. 5. of outer case,
top to bottom. not being separated by the fed plates o; but the spice, between the
sieve, and bed plates o, thereat, is separated therefrom by corner double angle iron
pieces o as shown in Fig. 1, which fig, also shews how the upper right hand corner
on plan Fig. 5, is separated off from hetween the top of each compartment, and the
perforated or woven sheet 1, by the corner side plates r. The lower right hand
corner on plan 5 if not required to form any passage, may be separated off by a
corner side plate continuous from top to bottom. The two left hand corners of
case i have openings. at bottom into tub, or case, el, having a spiral conveyor in
on a shaft revolved by a pulley and belt from motor engine shaft. Vertically up
through centre of filter case, is a shaft y revolved through a worm wheel thereon
from motor engine. Said slatt is made capable of being adjusted vertically within
given limits by an adjusting screw 10 on which it is stepped at bottom.
Shafty is fitted with scrapers I which revolve with shaft and which may he curved
as shown in plan at Fig. 4 or other shape. The serpers may be raised or lowered
to vary the depth of the layer of salts forming the filtering medium supported on the
sheets. The shaft y revolves at top in a stuffing hos y and provision is made by a
feather and groove whereby the shaft may be raised and lowered without disturbing
its worm wheel.
The
The operation is as follows:-The gases loaded with alkaline salts from the
furnace A. pass by pressure or suction, as indicated by the arrows, through the
furnace opening 6. into the cooler trap c, and thence along the conveyor tube d
wherein the salts, which partly deposit therein, are conveyed to the opening J
the salts fall on to the top supporting sheet 1, upon which they are uniformly
spread to any desired depth by the revolving scraper 11. The gases escape
through the sheets, to the vertical passage n, thence to the ontlet main, whence
it may be milized for heating or other purposes. In a new filter, deflector plates 14
may be employed to more expeditiously cover the sieves with the requisite layer of
alkaline salts, after attaining which they may be put out of action. The filter layer
being now prepared of the desired depth, when gases loaded with alkaline salts are
passed therethrough they are deprived of their alkaline salts, and the scraper
removing the excess, the operation becomes continuous. The excess salts are swept
over by the scrapers and fall to the hottom of the corner spaces thence through the

page_text: openings into the conveyor tube whereby they are conveyed to a receptacle (not
shewn) from which they may be collected.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what
I claim is.
1. The arrangement and combination of apparatus and machinery as and for the
purposes herein before set forth and shewn.
2. In combination with a furnace producing gases containing alkaline salts in
suspension a filtering apparatus consisting of an outer chamber i, divided into
compartments each having an adjustable scraper 11 and a false bottom t, for
supporting filter layer r, the space immediately above and below each false bottom
communicating respectively with the inlet through the corners, p, and the outlet
through corner passage u, all constructed, arranged, and combined as and for the
purposes hereinbefore described and shewn.
3. In combination with a furnace producing gases containing alkaline salts in.
suspension a filtering apparatus consisting of a crude gas compartment and a filtered
gas compartment separated from each other by a layer of the alkaline salts themselves.
maintained on a pervious support and through which layer the gas filters and the
thickness of which may be varied by a movable scraper 11 substantially as
herein before set forth.
4. In an apparatus for obtaining alkaline salts from blast furnace or other gases
the combination of a cooler-trap, a conveyor-pipo, a filter bed of "alkaline salts," and.
adjustable scraper, substantially as hereinbefore sot forth and shown.
Dated this 27th day of November 1896.
DAVID F. MASON,
Glasgow, Patent Agent..