Ix- PROVEMENTS IN PROCESSES AND APPARATUS FOR TREATING ALKALIPEROUS MINERALS TO OBTAIN ALKALIES, ALKALINE SALTS. ALUMINA, AND ACCESSORY PRODUCTS
Year: 1864

page_text: LETTERS PATENT to Frederick Oldfield Ward, of No. 6, Hertford Street,
May Fair, in the County of Middlesex, for the Invention of "Ix-
PROVEMENTS IN PROCESSES AND APPARATUS FOR TREATING ALKALIPEROUS
MINERALS TO OBTAIN ALKALIES, ALKALINE SALTS. ALUMINA, AND ACCESSORY
PRODUCTS."
1.
Sealed the 22nd November 1864, and dated the 2nd June 1864.
PROVISIONAL SPECIFICATION left by the said Frederick Oldfield Ward
at the Office of the Commissioners of Patents, with his Petition, on
the 2nd June 1864.
I, FREDERICK OLDFIELD WARD, of No. 6, Hertford Street, May Fair, in
the County of Middlesex, do hereby declare the nature of the Invention for
"IMPROVEMENTS IN PROCESSES AND APPARATUS FOR TREATING ALKALIPEROUS
MINERALS TO OBTAIN ALKALIES, ALKALINE SALTS, ALUMINA, AND ACCESSORY
.
PRODUCTS," to be as follows:-
.
こいい
101
1. This Invention relates to improvements on a process specified under
my Patent No. 3185, dated Dec. 30th, 1857, and mainly, characterised by.
the use of fluoride of calcium (fluor spar) in conjunction with earthy
material, perferably lime or its carbonate, or a mixture of the two, to
extract alkalies from natural alkaliferous silicates.
1
....
2. The said process comprises an extensive series of operations, some
preparatory, such as the selection, pulverization, apportionment, inter-
mixture, and coagglutination of the materials; others fundamental, as the
1...

page_text: chemical treatment, igneous, and aqueous, of the mixture; others supple-
mentary, as the boiling down and purification of the products, and the
utilization of the residuum.
3. Numerous trials of this process on an increasing scale of magnitude,
with a view to ascertain the most economical and advantageous means of
performing each of its stages on a manufacturing scale have led me to
discover a series of improvements which, taken severally and collectively,
constitute the subject matter of the present Invention.
4. The steps of the process are so numerous, and the economy of its
performance is so much influenced by varying local and other circumstances,
that the said improvements are also necessarily manifold, and comprise
alternative modes adapted respectively to the special conditions, favorable or
adverse, under which in particular cases the operation has to be carried on.
But though the number of my improvements is thus rendered considerable,
their scope on the other hand is confined within narrow limits, my claims
being expressly restricted to their use and application for the treatment of
alkaliferous minerals, so that for all other uses and applications whatsoever
they are, each and all of them, left unreservedly open and free.
5. Commencing with such of my said improvements as relate to the earlier
or preliminary steps of the process, and proceeding successively with those
referring to the fundamental and supplementary stages, they may be briefly
enumerated as folleme

page_text: 3. Replacement of part of the ordinary calcic, hydrate, or carbonate in my
mixture, whether in powder or compost, by an equivalent proportion of the
calcic residuum of the cryolite process, i.e., of the process for obtaining
soda and alumina from the mineral so called, which is a native double
fluoride of sodium and aluminium. The improvement is advantageous,
inasmuch as it turns to account a residuary product as a source of lime for
my purpose, and incidentally utilizes the artificial calcic fluoride asso-
ciated therewith, economizing proportionate quantities of the ordinary raw
materials of the process and of the cost of grinding the same.
4. Twofold utilization of cryolite itself, first, as a fluorine source in lieu
of calcic fluoride; secondly, as a contributory of alkali and alumina in aid
of the yield of my process. This improvement is beneficial in economizing
raw material and increasing the yield of saleable products.
5. Addition of pulverized chrome ore to either of the mixtures I employ,
the object of such addition being to fix the potash liberated from the rock
in the form of a valuable salt, the chromate. The advantages of this im-
provement consist in the prevention or diminution of the loss of potash by
volatilization, and in the simultaneous production at moderate cost of the
valuable salt above named.
process
to
B. Comminution of the materials used in my process.
my said
1. Reduction of the chalk and alkaliferous rock used in
different degrees of fineness by the use of sieves of different meshes, the
coarser to sift the chalk, the finer to sift the alkaliferous rock, the range of
admissible difference being such that the chalk sieve needs only to present per
square inch from half to a twelfth of the number of holes contained per square
inch in the alkaliferous rock sieve. The advantage of this improvement
consists in a sensible d'iminution of the grinding charges on the chalk I
employ when this is dry ground. Note.-When I employ wet grinding and
levigation for the comminution of the chalk this improvement does not apply.
C.-Mixing of the materials used in my process.
1. Wet mixing of my materials by mechanism of the nature of a pug mill
constructed so as to squeeze while cutting up and mixing them so as to deliver
them in the form of a plastic compost.
2. Dry mixing of my materials by means of a hopper and sieve or sievės
suitably arranged and shaken to receive and intermix my materials, and to
deliver them in the form of powder. On both systems, wet and dry, the
replenishment and evacuation of the mixing apparatus should go on simul-

page_text: taneously and continuously by the adaptation of ordinary arrangements to
that end, and the adjustments should be such as to effect a sufficiently but
not superfluously intimate admixture. The advantages of this improvement
are uniformity and adequacy of the results and economy in their attainment.
D. Subdivision and desiccation of my aforesaid compost.
1. Subdivision of my said compost into masses of indeterminate shape
and fragmentary character, but of determinate average size for ignition. This
may best be accomplished by first drying the moist pugmill product, then
breaking it to pieces, preferably of about hen's-egg size, or thereabouts, and
finally screening the mass through a screen of suitable mesh to retain the
pieces required, and to let the smalls and dust fall through.
2. Subdivision of my said compost into masses of determinate form and
size, whether rounded like balls or cakes, or angular, like bricks or tiles,
and whether solid or perforated, by means of one or other of the two systems
of moulding termed respectively moulding by impletion and moulding by
expression. Moulding by the direct application of the workman's hands to
knead and fashion the material into rounded cakes or balls I have found
on trial too expensive, and accordingly disclaim. The peculiarly adhesive
character of my compost renders it advisable to employ expedients for facili-
tating its delivery, whether in moulding it by impletion or by expression.
This I prefer to accomplish in the former case by lining the impletion mould
with a fabric having a pile-like plush or velvet to admit air freely, in the
latter case by fitting the expression die with side rollers to diminish friction.
The perforation of the masses may be accomplished on either system by
apparatus similar to that in use for making perforated bricks for building
purposes. The advantages are economy of labor, time, and cost, in sub-
dividing my compost into masses suitable for ignition, and adaptation of said
masses for more equable heating throughout.
2. Employment of mild artificial heat to eliminate gradually from iny
compost its mechanically held moisture before exposing it to the full heat of
ignition so as to prevent the crumbling of the compost during ignition, a point
of much practical importance for the correct performance of the furnace stage
of my operation on an extensive manufacturing scale. For this purpose I pre-
fer to employ one or other of the two following arrangements :-(1). Closed
drying sheds fitted with a double system of pipes or flues for the artificial
supply of warm air and the artificial withdrawal thereof charged with the
water of admixture of the compost, the temperature and rate of flow of
the said air currents being placed under control by suitable mechanical

page_text: arrangements. (2.) Preliminary dessication at a gentle heat of my compost
masses when already arranged in the kilns or the furnace itself in which the
full ignition is subsequently applied; this mode saves one extra removal and
stowage of the compost masses, but requires the provision of more kiln space.
Advantages. Both modes render the desiccation of my compost masses
independent of the weather, and enable the manufacture to be carried on
with proportionately increased regularity.
E.Ignition of my materials, whether (a) in compost or (b) in powder.
1. Adaptation of my compost masses for more equable ignition by
differentiating the conditions, physical or chemical, or both physical and
chemical, of different portions of the same charge respectively destined to
occupy hotter and cooler places in the kiln or furnace, the differentiation
being of such nature as to countervail, so far as may be, such inequalities of
temperature, and notwithstanding their adverse influence, to equalize the
furnace reaction. The masses may be physicallydifferentiated for thispurpose
by varying their size, shape, and the number and size of their perforations,
and they may be chemically differentiated by varying the relative supply of
the fluoride and other active ingredients in them. The advantage of this
improvement consists in its promoting the attainment of equable ignition in
working with imperfect furnaces.
F. Adaptation of kilns and furnaces to the purposes of my process.
Each form of kiln or furnace in use in the arts has some special kind of
advantage balanced for the most part by some countervailing defects so far as
regards its application to the purposes of my process. The un ler-mentioned
kinds, with the specified improvements and adaptations, are the best I am
acquainted with for my purpose.
1. Vertical kilns charged, discharged, and fired on the principle of the
ordinary continuously-working limekiln are available for my purpose, and
may. I find, be much improved for my purpose by constructing them with a
larger than the usual number of drawing holes below, as also in some cases
by adding a dome head and chimneys above, both the drawing holes and
chimneys being placed under the operator's control by dampers or other
equivalent contrivances for regulating the draught of air through the charge,
and so of controlling the ignition for the inspection of which a number of
sight holes are provided, myobject being bythese or equivalent arrangements
to facilitate the inspection and control of the operation in progress and the
more perfect equalization of the chemical reaction throughout all parts of the

page_text: charge. When a dome head is added to this form of kiln, apertures provided
with lids should be made in such dome for charging the kiln through.
(2.) Vertical kilus charged and discharged on the principle of the con-
tinuously working limekiln, but fired from without, are also available for my
purposes, and may be more perfectly adapted thereto by fitting them with
special arrangements of the nature of those mentioned in the preceding
paragraph.
(3.) Dome head kilns with perforated floors and the fires beneath the floor
adapted forintermittentor discontinuous action, charged and discharged cold,
like flare limekilns, and available for my purpose, and may be better adapted
thereto, partly by special arrangements of the nature of those referred to
above, partly by what I term a fire filter, i.e. a layer of calcic carbonate (or
other suitable material) interposed between the charge and the fire to take
the first brunt of the latter, and to purify its products of combustion of sul-
phurous acid products and of ash. This fire filter is available for use to like
ends in other forms of kilns and furnaces; it can be renewed as often as may
be found needful, and the lime produced by expulsion of carbonic acid is a bye-
product everywhere readily saleable.
4. Muffle kilns analogous to those used in burning stoneware in the
Lambeth potteries are available for the purposes of my process and may be
improved for the said purpose by forming beneath the floor horizontal con-
vergent flues extending respectively from each of the circumferential fires to
a central discharge flue communicating with a chimney stack, and by so
arranging the vertical flues of the said fires that this heat may be discharged
wholly below or wholly above, or partly above and partly below the dome in
any proportions at the operator's choice, the fires and their ash-pits having
doors and the flue dampers, so that the heat of the currents above, below,
and around the charge and each segment of it may be regulated as the
operator deems needful, sight holes being provided to enable him to view the
several segments of the charge at different levels, and to watch the progress
of the ignition thereof. Lastly, instead of the high conical chimney raised
above the dome of the Lambeth pottery ware kiln may be substituted mere
apertures in the dome or apertures fitted with chimney pots capable of
regulation by tiles placed thereon or dampers fitted up therein, so as still
further to facilitate the control of the ignition by the operator. Kilns of this
description, as well as several of the under-mentioned forms of kiln and
furnace and their modifications, may be arranged for firing as gas furnaces,
that is, may be heated by means of carbonic oxide and other carburetted gases
distilled from coal partially burned for the purpose of producing such gases

page_text: with an insufficient supply of air in a receptacle kept nearly closed, as is
now well understood, and in ordinary use and practice. The advantage of
such mode of heating for my purpose is, that it enables me more accurately
to direct and apply the gas flame to various parts of a kiln or furnace or
retort, or of a charge therein, and, if desired, to vary the direction of such
gas flame during the process of ignition, so as to raise the temperature of
under-heated portions of the charge or to moderate that of over-heated por-
tions, as the case may be.
5. Kilns of the descriptions mentioned in paragraphs 3 and 4,or of other
suitable descriptions, may be arranged in sets of three or more, and worked
in rotation in such manner that the charge or charges which are cooling
may warm the air which feeds the fire of the charge under ignition, while
the heat escaping from this fire passes on to commence the ignition of the
following charge or charges.
6. Kilns of the foregoing descriptions are suited for igniting my materials
in the form of compost. The four following forms of reverberatories, two.
fixed. and two rotating, are more particularly adapted for igniting my
materials in the form of powder or in that of the "smalls" and dust produced
when screening the fragmentary masses of my compost; nevertheless my
compost in larger masses may, if desired, be ignited in these reverberatories.
7. The ordinary reverberatory furnace may be specially adapted for my
purpose by arrangements for applying heat both above and below the bed,
preferably by means of two fires, one at each end of the furnace; this tends
very much to equalize the heat.
8. A reverberatory furnace may be constructed for my purpose of circu-
lar form with a low flat dome heated by the convergent heat streams
emanating from severally circumferentially placed fires, and conveyed away
by centrally placed apertures to an appropriate flue or flues. The bed may
be heated either above or below, or preferably both above and below. The
mechanical revolving agitators, referred to in a previous paragraph, are par-
ticularly well suited for a reverberatory of this description.
9. A reverberatory similar in form to the last, and heated in like manner
by circumferential fires, may be adapted to afford the equable heating
required for my purpose by fitting it up with a revolving bed, and fixed
rakes to stir or plough the material carried round beneath them. Means of
continuously charging in the materials at the centre and withdrawing them
at the circumference may also be adapted to this furnace, so as to render it
as nearly as possible automatic.
10. A reverberatory well suited to my purpose may be made of cylindri-

page_text: cal form like the shell of a Cornish boiler, lined with fire-brick, and made to
rotate on its horizontally disposed long axis. Its ends communicate by aper-
tures respectively with the fire and the chimney, and the two-fold effect of
its rotation is to roll the charge over and over so as to expose each part in
succession to the heat, at the same time uncovering to the flame every part of
the cylindrical bed in its turn. Suitable arrangements are of course provided
for charging and discharging the cylinder and for controlling the intensity
of the heat; this, as well as the three preceding forms of reverberatory, may
be readily muffled by interposing a suitable screen of fire-clay or cast iron to
prevent contact of the products of combustion with the materials under
ignition. In the cylindrical reverberatory now under description, such screen
takes the form of a tube extending from end to end of the cylinder, and fitted
into its terminal apertures; in the others it becomes a second arch or dome
extending beneath the first, and having between the two a space or flue for
the flames to play through. The waste heat of all these furnaces and kilns
may be utilized by conveyance beneath drying floors or evaporating pans,
or through drying sheds to prepare the materials or boil down the products
of the process.
G. Lixiviation of the furnace product.
1. The ordinary serially arranged pans for methodical lixiviation may be
specially adapted for my purpose by making them of circular form, and
fitting each with a perforated basket to hold the larger lumps of frit, an
agitator below the basket to stir the "smalls" aud dusty portion which
fall through to the bottom of the pan beneath, and a steam pipe or other
equivalent arrangement for heating the liquor of lixiviation.
2. Addition of lime or of carbonated alkali, or of caustic alkali, or of two
or more of these, to the liquor of ebullition or lixiviation during the
aqueous treatment of imperfectly or excessively fritted material augments often
very sensibly the yield therefrom. The advantage of this improvementis obvious.
H.-Purification of the alkaline products and recovery of ingredients
separated therefrom as useful bye-products.
1. Aeration of the lye with common air in fine streams to eliminate iron
and to obviate its falling in association with alumina, treatment of the lye
after such preparatory aeration with carbonic acid to precipitate alumina in a
proportionately purer state. Utilization for this purpose of the carbonic acid
given off by my materials under ignition, or of the carbonic acid yielded by
the fuel I employ, and washing of such carbonic acid before use whenever it

page_text: is found to be contaminated with sulphurous acid or other hurtful impurity
soluble in water,such washing being preferably accomplished bypassing it up
a coke tower down which water is made to trickle in fine films. Potassic
sulphate and sodic carbonate, when sufficiently abundant in the lye to justify
separation, may be eliminated by usual chemical means.
I. Utilization of the residuum.
2. Improved adaptation of the lixiviated residium to serve in some cases as
a material of cement; in other cases as a material of bricks by the addition
thereto in the first case of material of septarian origin, and of the character
of that employed in conjunction with chalk in making artificial cements. In
the second case of siliceous material, preferably of the moresoluble kind, like
that found under the chalk beds at Farnham.
SPECIFICATION in pursuance of the conditions of the Letter Patent, filed
by the said Frederick Oldfield Ward in the Great Seal Patent Office.
on the 2nd December 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK,
OLDFIELD WARD, of No. 6, Hertford Street, May Fair, in the County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Second day of June, in the year of our Lord One
thousand eight hundred and sixty-four, in the twenty-seventh year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Frederick Oldfield Ward, Her special licence that I, the said Frederick
Oldfield Ward, my executors, administrators, and assigns, or such others as I,
the said Frederick Oldfield Ward, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and at all
timesthereafter during the term therein expressed,should and lawfully might,
make, use, exercise and vend, within the United Kingdom of Great Britain.
and Ireland, the Channel Islands, and Isle of Man, an Invention for
'IMPROVEMENTS IN PROCESSES AND APPARATUS FOR TREATING ALKALIFEROUS
MINERALS TO OBTAIN ALKALIES, ALKALINE SALTS, ALUMINA, AND ACCESSORY
PRODUCTS," upon the condition (amongst others), that I, the Frederick
Oldfield Ward, my executors or administrators, by an instrument in writing
under my,or their, or one of their hands and seals, should particularly describe

page_text: and ascertain the nature of the said Invention, and in what manner the same
was to be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said Frederick Oldfield Ward, do hereby
declare the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement thereof; that is to say:-
1. This Invention relates to improvements on a process specified under my
Patent No. 3185, dated December 30th, 1857, and mainly characterised by
the use of fluoride of calcium (flour spar) in conjunction with earthy
material, preferably lime or its carbonate, or a mixture of the two, to extract
alkalies from natural alkaliferous silicates.
2. The said process comprises an extensive series of operations, some
preparatory, such asthe selection, pulverization, apportionment, intermixture,
and coagglutination of the materials; others fundamental, as the chemical
treatment, igneous and aqueous, of the mixture; others supplementary, as
the boiling down and purification of the products and the utilization of the
residuum.
3. Numerous trials of this process on an increasing scale of magnitude
with a view to ascertain the most economical and advantageous means
of performing each of its stages on a manufacturing scale, have led me
to discover a series of improvements which taken severally and collectively
constitute the subject matter of the present Invention.
4. The steps of the process are so numerous, and the economy of its per-
formance is so much influenced by varying local and other circumstances,
that the said improvements are also necessarily manifold and comprise
alternative modes adapted respectively to the special conditions, favorable
or adverse, under which in particular cases the operation has to be carried
But though the number of my improvements is thus rendered con-
siderable, their scope on the other hand is confined within narrow limits,
my claims being expressly restricted to their use and application for the
treatment of alkaliferous minerals, so that for all other uses and appli-
cations whatsoever they are each and all of them left unreservedly open and
free.
on.
5. Commencing with such of my said improvements as relate to the
earlier or preliminary steps of the process, and proceeding successively with
those referring to the fundamental and supplementary stages, they may be
briefly enumerated as follows:--

page_text: I. PRELIMINARY.
A. Selection,apportionment, and coagglutination, of the materials used
in my process.
1. Reduction of the proportion of lime in the mixture of lime, chalk, and
water employed to form a coherent compost for the purposes of my process.
The proportion formerly indicated by me was one equivalent each of lime
and chalk, or (by weight) 28 of the former and 50 of the latter, whereas
the proportion which subsequent trials lead me now to recommend ranges
from 14 parts to 80 little as 1 part of lime (by weight) against 50
parts of chalk, the advantages being economy of the more costly of the
two materials, increase of the fusibility of the compost, and greater porosity
of the furnace product.
2. Use of chalk and limestone conjointly (instead of chalk only) to form,
in admixture with lime and water, a coherent compost for the purposes of my
process, the advantage being an important diminution ofcostinmanylocalities.
3. Replacement of part of the ordinary calcic, hydrate, or carbonate in
my mixture, whether in powder or compost, by an equivalent proportion
of the calcic residuum of the cryolite process, i.e., of the process for
obtaining soda and alumina from the mineral so called, which is a native
double fluoride of sodium and aluminium. Theimprovement isadvantageous
inasmuch as it turns to account a residuary product as a source of lime
for my purpose, and incidentally utilizes the artificial calcic fluoride asso-
ciated therewith, economising proportionate quantities of the ordinary raw
materials of the process, and of the cost of grinding the same.
4. Twofold utilization of cryolite itself, first, as a fluorine source in lieu
of calcic fluoride, and secondly, as a contributory of alkali and alumina, in
aid of the yield of my process. This improvement is beneficial in econo-
mizing raw material and increasing the yield of saleable products.
5. Addition of pulverized chrome ore to either of the mixtures I employ,
the object of such addition being to fix the potash liberated from the rock
in the form of a valuable salt, the chromate. The advantages of this im-
provement consist in the prevention or diminution of the loss of potash by
volatilization, and in the simultaneous production at moderate cost of the
valuable salt above-named.
B. Comminution of the materials used in my process.
1. Reduction of the chalk and alkaliferous rock used in my said process
to different degrees of fineness by the use of sieves of different meshes, the

page_text: per
coarser to sift the chalk, the finer to sift the alkaliferous rock, the range of
admissible difference being such that the chalk sieve needs only to present
per square inch from half to a twelfth of the number of holes contained
square inch in the alkaliferous rock sieve. The advantage of this improve-
ment consists in a sensible diminution of the grinding charges on the chalk
I employ when this is dry ground.
Note. When I employ wet grinding and levigation for the comminution
of the chalk, this improvement does not apply.
C. -Mixing of the materials used in my process.
1. Wet mixing of my materials by mechanism of the nature of a pug mill
constructed so as to squeeze while cutting up and mixing them, so as to
deliver them in the form of a plastic compost.
2. Dry mixing of my materials by means of a hopper and sieve or sieves
suitably arranged and shaken to receive and intermix my materials, and
to deliver them in the form of powder. On both systems, wet and dry,
the replenishment and evacuation of the mixing apparatus should go on
simultaneously and continuously by the adaptation of ordinary arrangements
to that end, and the adjustments should be such as to effect a sufficiently
but not superfluously intimate admixture. The advantages of this improve-
ment are uniformity and adequacy of the results, and economy in their
attainment.
D.-Subdivision and desiccation of my aforesaid compost.
1. Subdivision of my said compost into masses of indeterminate shape
and fragmentary character, but of determinate average size, for ignition.
This may best be accomplished by first drying the moist pug-mill product,
then breaking it to pieces, preferably of about hen's-egg size or thereabouts,
and finally screening the mass through a screen of suitable mesh to retain
the pieces required and to let the smalls and dust fall through.
2. Subdivision of my said compost into masses of determinate form and
size, whether rounded like balls or cakes, or angular like bricks or tiles, and
whether solid or perforated, by means of one or other of the two systems of
moulding termed respectively moulding by impletion and moulding by ex-
pression. Moulding by the direct application of the workman's hands to
knead and fashion the material into rounded cakes or balls I have found on
trial too expensive,and accordinglydisclaim. The peculiarlya hesive character
of my compost renders it advisable to employ expedients for facilitating its
delivery whether iu moulding it by impletion or by expression. This I prefer

page_text: to accomplish in the former case by lining the impletion mould with a fabri
having a pile-like plush or velvet to adinit air freely, in the latter case by
fitting the expression die with side rollers to diminish friction. The per-
foration of the masses may be accomplished on either system by apparatus
similar to that in use for making perforated bricks for building purposes.
The advantages are, economy of labor, time, and cost in subdividing my com
post into masses suitable for ignition, and adaptation of said masses for more
equable heating throughout.
:
3. Employment of mild artificial heat to eliminate gradually from my
compost its mechanically-held moisture before exposing it to the full heat of
ignition, so as to prevent the crumbling of the compost during ignition,a point
of much practical importance for the correct performance of the furnace stage
of my operation on an extensive manufacturing scale. For this purpose I
prefer to employ one or other of the two following arrangements: -(1.) Closed
drying sheds fit ed with a double system of pipes or flues for the artificial
supply of warm air, and the artificial withdrawal thereof charged with the
water of admixture of the compost, the temperature and rate of flow of the
said air currents being placed under control by suitable mechanical arrange-
ments (2.) Preliminary desiccation at a gentle heat of my compost masses
when already arranged in the kiln or furnace itself in which the full ignition.
is subsequently applied; this mode saves one extra removal and stowage of
the compost masses, but requires the provision of more kiln space.
Advantages. Both modes render the desiccation of my compost masses
independent of the weather, and enable the manufacture to be carried on with
proportionately increased regularity.
E.-Iguition of my materials, whether (a) in compost or (b) in powder.
1. Adaptation of my compost masses for more equable ignition by differen-
tiating the conditions, physical or chemical, or both physical and chemical, of
different portions of the same charge respectively destined to occupy hotter
and cooler places in the kiln or furnace, the differentiation being of such
nature as to countervail, so far as may be, such inequalities of temperature,
and, notwithstanding their adverse influence, to equalize the furnace reaction.
The masses may be physically differentiated for this purpose by varying their
size, shape, and the number and size of their perforations, and they may be
chemically differentiated by varying the relative supply of the fluoride and
other active ingredients in them. The advantage of this improvement consists
in its promoting the attainment of equable ignition in working with imperfect
furnaces.

page_text: F-Adaptation of kilns and furnaces to the purposes of my process.
Each form of kiln or furnace in use in the arts has some special kind of
advantage, balanced for the most part by some countervailing defects so far as
regards its application to the purposes of my process. The under-mentioned
kinds, with the specified improvements and adaptations, are the best I am
acquainted with for my purpose.
1. Vertical kiln charged, discharged, and fired on the principle of the
ordinary continuously-working lime kiln are available for my purpose, and
may, I find, be much improved for my purpose by constructing them with a
larger than the usual number of drawing holes below, as also, in some cases,
by adding a dome head and chimneys above, both the drawing holes and
chimneys being placed under the operator's control by dampers or other
equivalent contrivances for regulating the draft of air through the charge,and
so of controlling its ignition, for the inspection of which a number of sight
holes are provided, my object being, by these or equivalent arrangements, to
facilitate the inspection and control of the operation in progress and the more
perfect equalization of the chemical reaction throughout all parts of the
charge. When a dome head is added to this form of kiln, apertures provided
with lids should be made in such dome for charging the kiln through.
2. Vertical kilns charged and discharged on the principle of the con-
tinuously-working lime kiln, but fired from without, are also available for my
purpose, and may be more perfectly adapted thereto by fitting them with
special arrangements of the nature of those mentioned in the preceding
paragraph.
3. Dome-head kilns with perforated floors and the fires beneath the floor
adapted for intermittent or discontinuous action, charged and discharged cold,
like flare linekilns, are available for my purpose, and may be better adapted
thereto partly by special arrangements of the nature of those referred to above,
partly by what I term a fire-filter, i.e., a layer of calcic carbonate (or other
suitable material) interposed between the charge and the fire to take the first
brunt of the latter and to purify its products of combustion of sulphurous acid
products and of ash. This fire-filter is available for use to like ends in other
forms of kilns and furnaces; it can be renewed as often as may be found
needful, and the lime produced by expulsion of carbonic acid is a bye product
everywhere readily saleable.
4. Muffle kilns analogous to those used in burning stoneware in the Lam-
beth potteries are available for the purposes of my process, and may be
improved for the said purpose by forming beneath the floor horizontal con.

page_text: vergent flues extending respectively from each of the circumferential fires
to a central discharge flue communicating with a chimney stack, and by so
arranging the vertical flues of the said fires that their heat: may be discharged
wholly below or wholly above, or partly above and partly below the dome, in
any proportions, at the operator's choice, the fires and their ash-pits having
doors and the flues dampers, so that the heat of the currents above, below,
and around the charge, and each segment of it, may be regulated as the
operator deems needful, sight-holes being provided to enable him to view the
several segments of the charge at different levels and to watch the progress of
the ignition thereof. Lastly, instead of the high conical chimney raised above
the dome of the Lambeth pottery-ware kiln may be substituted mere apertures
in the dome, or apertures fitted with chimney pots capable of regulation by
tiles placed thereon or dampers fitted up therein, so as still further to facilitate
the control of the iguition by the operator.
Kilns of this description, as well as several of the under-mentioned forms of
kilns and furnace and their modifications, may be arranged for firing as gas
furnaces, that is, may be heated by means of carbonic oxide and other car-
burretted gases distilled from coal partiallyburned for the purpose of providing
such gases with an insufficient supply of air in a receptacle kept nearly closed,
as is now well understood and in ordinary use and practice. The advantage
of such mode of heating for my purpose is, that it enables me more accurately
to direct and apply the gas flame to various parts of a kiln, or furnace, or
retort, or of a charge therein, and, if desired, to vary the direction of such gas
flame during the process of ignition, so as to raise the temperature of under-
heated portions of the charge or to moderate that of over-heated portions, as
the case may be.
5. Kilns of the descriptions mentioned in paragraphs 3 and 4, or of other
suitable descriptions, may be arranged in sets of three or more, and worked in
rotation in such manner that the charge or charges which are cooling may
warm the air which feeds the fire of the charge under ignition, while the hrat
escaping from this fire passes on to commence the ignition of the following
charge or charges.
6. Kilns of the foregoing descriptions are suited for igniting my materials in
the form of compost. The four following forms of reverberatories, two fixed
and two rotating, are more particularly adapted for igniting my materials in
the form of powder or in that of the "smalls" and dust produced when
screening the fragmentary masses of my compost. Nevertheless, my compost
in larger masses may, if desired, be ignited in these reverberatories.
7. The ordinary reverberatory furnace may be specially adapted for my

page_text: purpose by arrangements for applying heat both above and below the bed.
preferably by means of two fires, one at each end of the furnace. This tends
very much to equalize the heat.
8. A reverberatory furnace may be constructed for my purpose of circular
form with a low flat dome heated by the convergent heat streams emanating
from several circumferentially-placed fires, and conveyed away by centrally-
placed apertures to an appropriate flue or flues. The bed may be heated either
above or below, or preferably both above and below. The mechanical re-
volving agitators, referred to in a previous paragraph, are particularly well
suited for a reverberatory of this description.
9. A reverberatory similar in form to the last and heated in like manner by
circumferential fires may be adapted to afford the equable heating required
for my purpose by fitting it up with a revolving bed, and fixed rakes to stir or
plough the material carried round beneath them. Means of continuously
charging in the materials at the centre and withdrawing them at the circum-
ference may also be adapted to this furnace, so as to render it as nearly as
possible automatic.
10. A reverberatory well suited to my purpose may be made of cylindrical
form, like the shell of a Cornish boiler, lined with fire-brick, and made to
rotate on its horizontally disposed long axis. Its ends communicate by
apertures respectively with the fire and the chimney, and the twofold effect of
its rotation is to roll the charge over and over, so as to expose each part in
succession to the heat, at the same time uncovering to the flame every part of
the cylindrical bed in its turn. Suitable arrangements are of course provided
for charging and discharging the cylinder, and for controlling the intensity of
the heat. This, as well as the three preceding forms of reverberatory may be
readily muffled by interposing a suitable screen of fire-clay or cast iron to
prevent contact of the products of combustion with the materials under ignition.
In the cylindrical reverberatory now under description, such screen takes the
form of a tube extending from end to end of the cylinder, and fitted into its
terminal apertures; in the others it becomes a second arch or dome extending
beneath the first, and leaving between the two a space or flue for the flames
to play through. The waste heat of all these furnaces and kilns may be
utilized by conveyance beneath drying floors or evaporating pans, or through
drying sheds, to prepare the materials or boil down the products of the
process.
G. Lixiviation of the Furnace Product.
1. The ordinary serially arranged pans for methodical lixiviation may be
Specially adapted for my purpose by making them of circular form, and fitting

page_text: each with a perforated basket to hold the larger lumps of frit, an agitator
below the basket to stir the "smalls" and dusty portion which fall through
to the bottom of the pan beneath, and a steam pipe or other equivalent
arrangement for heating the liquor of lixiviation.
2. Addition of lime or of carbonated alkali, or of caustic alkali, or of two
or more of these, to the liquor of ebullition or lixiviation during the aqueous
treatment of imperfectly or excessively fritted material, augments often very
sensibly the yield therefrom. The advantage of this improvement is obvious.
-
H. Purification of the Alkaline Products and Recovery of Ingredients
separated therefrom as useful Bye-products.
1. Aëration of the lye with common air in fine streams to eliminate iron,
and to obviate its falling in association with alumina treatment of the lyeafter
such preparatory aëration with carbonic acid to precipitate alumina in a pro-
portionately purer state. Utilization, for this purpose, of the carbonic acid
given off by my materials under ignition, or of the carbonic acid yielded by.
the fuel I employ, and washing of such carbonic acid before use, whenever
it is found to be contaminated with sulphurous acid or other hurtful impurity
soluble in water, such washing being preferably accomplished by passing it
up a coke tower down which water is made to trickle in fine films. Potassic
sulphate and sodic carbonate, when sufficiently abundant in the lye to
justify separation may be eliminated by usual chemical means.

page_text: my materials when so made up into compost; while in paragraphs F. 6, 7, 8,
9, and 10,descriptions are given of kilns adapted to ignite my materials when
merely pulverised and mixed and not made up into compost. In choosing
between these two modes of operating, whether on materials, &c., merely
powdered, or on materials made up into compost, the operator should be
guided by local circumstances, particularly by the relativo abundance and cost
of the water or other power, and of the labor, capital, fuel, limestone, and
chalk at his disposal. The object is to obtain equable ignition of all parts of
the mass under treatment, and equable reaction of the earthy ingredients on
the alkaliferous rock, by the least expensive means. If labor for stirring the
materials during ignition be cheap,and still more, if water or other power and
capital to apply it mechanically be abundant in the operator's neighbourhood,
while either of the ingredients requisite for making the compost is scarce,
it may be cheaper to treat the materials in the form of powder, employing
agitation by hand or by power, as the case may be, to effect the equable
distribution of heat throughout the mass. On the contrary, in localities
where the calcic ingredients of the compost are abundant and cheap, while
agitation is from any cause a comparatively costly process, one or other of
the above-described methods of igniting the materials made up into solid
masses may advantageously be adopted.
Like considerations should govern the choice of the proportions of the
materials employed in each case. Thus in parh. A. 1 a range of from 14
parts down to so little as 1 part of lime against 50 parts of chalk is given,
but as the extreme minimum of lime indicated gives but a moderate degree
of coherency, this should be adopted only in localities where the excess of
the cost of lime over that of chalk is so great as to make extra breakage of
the cakes or masses of compost a minor evil.
In like manner the replacement of part of the ordinary calcic hydrate or
carbonate by the residuum of the cryolite process, as recommended in para-
graph A. 3, can only be practised with advantage in such proximity to a
cryolite working factory or under such conditions of transport therefrom as
may admit of the economical conveyance of the residuum in question to
the felspar working factory, and in judging of this for any given locality,
regard must of course be had to the cost in that locality of ordinary calcic
hydrate, carbonate, and fluoride which the cryolite residuum would replace.
So again the use of cryolite itself as a fluorine source recommended in
paragraph A. 4 depends for its economy in any given locality on the relative
price there of fluor spar and cryolite, due regard being also had to the value

page_text: recoverable from the cryolite in the form of soda and alumina, which value is
greatly in excess of the value left behind by the fluor spar in the calcic
residuum of the
process.
The use of chrome ore, as indicated in paragraph A. 5, is, of course, only
advantageous when it is desired to obtain the liberated alkali in the form of
chromate. The proportion of chrome ore and felspar should accordingly be
such that the alkali derived from the latter, and the chromic acid supplied by
the former, may be in equivalent proportions, which implies for average
samples of the two minerals, about 4 parts by weight of felspar to one of
chrome ore. The calcic fluoride added may be about th of the weight of
the felspar, and should any other than calcic fluoride be used, an equivalent
portion of such other fluoride may be supplied. The ignition may be
conducted at a lower temperature and continued for a shorter time than the
temperature and time commonly employed when working chrome ore without
felspar. These data, however, are not put forward as absolute, they may be
considerably varied without substantially departing from the Invention, but
an operator of ordinary skill may, with a little practice and these indications
for his guidance, may readily adapt the several conditions of the process to
the quality of the minerals at his disposal.
With reference to the use of sieves of different degrees of fineness to sift
the chalk and the alkaliferous rock respectively (as recommended in para-
graph B. 1), I may mention that I have obtained good results when using for
the chalk sieves having 26 holes to the linear inch, and for the alkaliferous
rock sieves having 90 holes to the linear inch, which numbers I accordingly
recommend without restricting myself.thereto.
With reference to the pug-mill for squeezing, cutting up, and mixing my
materials in the wet state, as suggested in paragraph C. 1, this effect is best
obtained by making the arms of the pug-mill of a flat shape, like oar-blades,
and setting these in archimedean screw fashion, so as to represent successive
portions of a spiral, the inclination being such relatively to the direction of
the rotation that the blades may press the materials downwards, while cutting
and mixing them. The delivery aperture or apertures below may be regu-
lated as to size so as to let the compost pass out slowly enough to ensure its
adequate mixture before expulsion, and the feeding in of the materials at the
top may be proportionately regulated as to speed by any of the ordinary
mechanical means to that end.
The dry mixing arrangements mentioned in paragraph C. 2, may consist of
two or more sieves superposed, and it is not necessary that these should be of
very fine mesh. I have found sieves of 8 or 10 holes to the linear inch

page_text: answer as mixers very well, and I recommend for this purpose such a mesh,
or thereabouts, without confining myself thereto. In dry mixing of the
materials particular care should be taken to have the chalk thoroughly dry,
as otherwise this may run into clots, and the blending be so rendered less
uniform and complete than is desirable.
The screen referred to in paragraph D. 1 for obtaining fragments of
average size for ignition may advantageously have such a mesh as to retain
pieces of hen's-egg size or thereabouts, but this dimension may be considerably
varied without materially affecting the practical result.
For moulding the compost into pieces of determinate form, as mentioned
in paragraph D. 2, I prefer on the whole the expression to the impletion
system, and of the various forms of machinery for moulding by expression.
I prefer the well-known brick moulding machinery, patented and sold by
Henry Clayton & Co., of London. The arrangement of drying sheds for
drying bricks, devised by the above-named manufacturers, I also recommend
as very applicable for the purpose of drying my compost bricks, as mentioned
in paragraph D. 3; but in cases where capital abounds, and the provision of
extra kiln space is consequently not an obstacle, I prefer the preliminary
dessication to be performed in the kiln itself, as set forth in paragraph D. 3.
In differentiating the conditions, physical, chemical, or both physical and
chemical, of my compost masses to adapt them for equable ignition in fur-
naces not equably heated throughout, I increase the dose of fluoride in
the masses destined to occupy the cooler places, or I diminish their size or
multiply the number of their perforations, or give them a shape presenting
more extended surfaces to the heat; or I employ two or more of these expe-
dients in combination, guiding myself as to the degree of such differentiation
by noting the results of successive trials under various kinds and degrees of
differentiation in the particular kiln or furnace at disposal.
The sight-holes referred to in paragraph F. 1 may advantageously be
formed or pierced through the kilns wall, and tubes of fire-clay may be
inserted in each such hole, and each tube have a plug to close it when not
in use.
I have found it advantageous to dispose these sight-holes in three
zones, a lower, middle, and an upper zone, and to have five or six sight-
holes in each zone, so that a view may be commanded of every part of the
ignited mass. 1 also prefer to construct such kilns with six drawing holes at
least, and also with six chimneys at least around the dome, besides the usual
central aperture or chimney of the dome, and besides at least 4 charging
apertures to feed the kiln through, each of which apertures should have a lid
to close it when required.

page_text: The vertical kilns mentioned in paragraph F. 2, may be formed of two
concentric cylindrical walls, between which the fire may be made to pass in
the usual way, as is well understood by furnace builders. The fire-places
should, however, as in the last case, be twice as numerous as usual to ensure
a distribution as equal as possible of the heat. The internal diameter of the
inner cylinder I prefer to make not exceeding 40 inches. The sight tubes for
inspecting the charge must of course pass through both walls and traverse the
intervening space, and they may be disposed in zones, as in the modified
lime kiln described in the preceding paragraph.
The intermittently acting dome-head kilns, referred to in paragraph F.3,may
be constructed in the main like ordinary flare limekilns, save and as regards
the perforated floor, which does not exist in ordinary flare limekilus, but
which I prefer to interpose to take the first brunt of the fires which are dis-
posed under this floor. I also provide fire-places of half the usual size and
twice the usual number as compared to ordinary flare limekilns, the better
to distribute the heat, and I provide 6 or 7 short chimneys around the dome-
head in addition to the usual central aperture for discharging smoke, and I fit
each of these chimneys with a damper, so that I may by urging this or that
fire or fires below, and opening this or that damper or dampers above, give
to the kiln heat such intensity, and also such direction through the ignited
mass as inspection through the sight-holes (disposed as above described)may
show t be needful to secure equability of ignition.
The nature and action of the "fire-filter" described in the same paragraph
(F. 3), require no further elucidation. The description of the muffle kiln in
paragraph F. 4 is also, I believe,sufficiently full to enable a practical furnace
builder,guided by the general indications herein-before given, and keeping in
view my main object, viz., to secure equability of ignition at a moderate tem-
perature, to execute such a kiln without difficulty, whether the heating is
to be performed by means of ordinary fires, or by the gas fibres referred to in
paragraph F. 4, and producible by the partial burning and distillation of
bituminous fuel, as is now well understood. I deem it therefore superfluous
to enter upon minute descriptions of distributing flues for circulating heat,and
dampers for giving it this or that direction at the operator's choice, seeing
that such special arrangements are susceptible of variation almost ad infinitum
without material variation of the result, provided that care be taken so to
construct the flues and dampers that heat may be diverted from such parts of
the kiln as the sight-holes may show to be getting too hot, and diverted to
such other parts as the sight-holes may show to be getting too cool. The
instructions in paragraph F. 5 are also, I believe, sufficient to guide a prac-

page_text: tised furnace builder to the accomplishment of the end therein mentioned
without entering on a minute description of the connecting flues required
for its attainment.
The reverberatory furnace (paragraph F. 5) may be heated both above and
below the bed as recommended, either by a fire placed at one end thereof, the
heat in this case being first conducted above the bed and then at the end of
the bed led downward, and caused to travel back beneath the bed through
flues formed under it for the purpose, and communicating with the chimney-
stack, through which it may be finally discharged, as is well understood, or
else the effect of heating both above and below may be obtained by providing
a fire-place at each end of the reverberatory one, sending its heat as usual
over the bed and charge, the other sending its heat in the opposite direction
under the bed,and this latter heat current being allowed to pass through an
aperture below the fire-bridge,and there to mingle with the heat current of
the other fire and to proceed along with it over the charge to the flue,and so
on to the chimney stack. On its way to the chimney this heat current may
be utilized by passing it beneath an evaporating pan, which may be set for
this purpose above the arch of the furnace, with a space or flue beneath it
for the heat to travel through; but in this case it is convenient to provide a
separate flue governed by a damper, through which to pass the current when
the evaporating pan is not in use, all which is well understood by furnace
builders.
The well-known furnace called Brunton's calciner, and extensively used
for calcining pyritic ore in Corawall, may serve as a model for imitation in
carrying out the revolving bed furnace referred to in paragraph F.9,and the
furnace recommended in paragraph F. 8 may resemble this except in its
having the bed fixed and the agitator made to revolve. I prefer, however,
to have more fire-places than the two which Brunton employs. I prefer also
to carry the smoke away by centrally placed apertures in the dome of the
furnace (paragraph 6) instead of by the side apertures which Brunton em-
ploys; and these central apertures I make in the dome for that part of the
products of combustion which I lead above the bed, while that part of the
products of combustion which I lead beneath the bed are conveyed away to
the chimney by an under flue specially formed for the purpose.
The cylindrical rotary reverberatory recommended in paragraph F. 10 may
be constructed on the model of that patented April 13th, 1853 (Patent
No. 887) by Messrs. Elliott & Russell, for use in the manufacture of soda.
The lixiviating apparatus recommended in paragraph G. 1 has for its
object to relieve the agitators from needlessly turning round the larger masses

page_text: of frit and applying them to stir only the small and dust, these being the
only portions which need stirring to hinder them from "" setting" into a
kind of concrete, as they are apt to do unless agitated during ebullition.
l'aragraph G. 2 needs little explanation. A small per-centage of the
ingredient or ingredients named may first be added and increased by sub-
sequent additions as long as the yield is found to be thereby improved, a
question readily determined by the usual tests.
The aëration mentioned in paragraph H. 1 may be carried out either by
means of a vat, having at the bottom a flat spiral coil of pipe pierced with
numerous holes and supplied with air by an air pump driven (preferably) by
power, or by simple mechanical agitation of the fluid in presence of common
air. After atmospheric aeration for about 3 hours (more or less) an equal
time (more or less) may be allowed for the subsidence, of the oxidized iron,
and from this the lye should be decanted before its acration with carbonic.
acid by similar or equivalent means to throw down the dissolved alumina.
When the carbonic acid of the products of combustion of some or all of the
various fires of the establishment is to be employed for aerating purposes, a
rotating fan may be employed to draw it from the flues through the coke
tower washer (as described in paragraph H. 1), and to urge it thus purified
through the perforated coil in the vat into the lye. The requisite carbonic
acid may, however, be made expressly for the purpose by burning coke or
by treating calcic carbonate with hydrochloric or sulphuric acid if preferred,
care being taken in either case to purify it by washing as above recom-
mended. The supply of carbonic acid should be discontinued as soon as a
portion of the lye when filtered shews no precipitate or scarcely any on
addition of a little solution of alkaline bicarbonate. When sufficiently
saturated with carbonic acid the lye may be allowed to settle for about two
hours and decanted or syphoned or pumped off from the aluminous
precipitate, which requires washing first with weak lye, afterwards with
water, to free it from most of the adherent alkali. It will then be pure
enough for use in the mauufacture of potash, alum, or alum casee, and
higher degrees of purity (if desired) may be given to it by usual chemical
means. The alkaline washings of the alumina may be used instead of
water in lixiviating the next batch of frit, so as to return the alkaline
matter into the general mass of potash produced, thus avoiding waste.
In utilizing the insoluble residuum or lixiviated frit by the means recom-
mended in paragraph 1. 1, the mud of rivers running through formations
which (like the London clay) contain septarian nodules may be advan-
tageously employed, and I have obtained good results in using this mud

page_text: and my residuum in equal proportions, and adding to the mass as much
chalk as would suffice to produce Portland cement were it added to the
river mud alone.
For brickmaking purposes I recommend the admixture of my residuum
with an equal weight of good plastic clay, to which an equal proportion of
soluble silica, such as that which is found underlying the chalk beds at
Farnham, may also be added with advantage.
Having thus stated to the best of my ability the nature and purport of
the various improvements comprised in my present Invention, and the best
means I am acquainted with for carrying them into effect, adding such
detailed indications as will, I believe, enable any person conversant with
manufactures of this class to execute them readily, I would in conclusion
disclaim each and all of the herein described apparatus and processes as
regards the general bearings and application thereof, expressly confining
my claims thereunto to the special application thereof, to facilitate the
liberation of potash or soda, or both (as the case may be) by aid of lime
and fluorine from natural alkaliferous silicates.
In witness whereof, I, the said Frederick Oldfield Ward, have here-
unto set my hand and seal, this Second day of December, in the
year of our Lord One thousand eight hundred and sixty-four.
FREDERICK OLDFIELD WARD. (L.S.)