IMPROVE- MENTS IN TREATING IRON TO OBTAIN METALLIC COMPOUNDS FOR VARIOUS USES
Year: 1867

page_text: LETTERS PATENT to Andrew Linmere Dowie, of Glasgow, in the County
of Lanark, North Britain, Merchant, for the Invention of "IMPROVE-
MENTS IN TREATING IRON TO OBTAIN METALLIC COMPOUNDS FOR VARIOUS
USES."
Sealed the 12th November 1867, and dated the 17th May 1867.
PROVISIONAL SPECIFICATION left by the said Andrew Linmere Dowie
at the Office of the Commissioners of Patents, with his Petition, on the
17th May 1867.
I, ANDREW LINMERE DOWIE, of Glasgow, in the County of Lanark, North
Britain, Merchant, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN TREATING IRON TO OBTAIN METALLIC COMPOUNDS FOR VARIOUS
USES," to be as follows:-
This Invention has for its object to obtain various metallic compounds having
iron as the chief ingredient, and possessing various properties of great value
in many useful applications.
The Invention comprises the following features of novelty :-Firstly, the
preparation of ordinary pig iron by melting it with oyster or other marine
shells; secondly, the melting of the prepared iron along with an intimate
mixture of rock salt and borax, with tin, and with an intimate mixture
consisting of iodine or bromine and manganese, oxide of manganese, antimony,
or oxide of antimony; and, thirdly, the remelting of the compound with an

page_text: intimate mixture of tartar and cream of tartar. In the first or preparatory
process a salt or salts of soda, potash, lime, baryta, or strontia may be sub-
stituted for the marine shells; in the second or compounding process copper
or other metal or metals may be introduced along with or in place of the tin;
or the compound may be remelted with copper or other metals or with fresh
or prepared pig iron, or in some cases the tin may be omitted.
The proportions of the ingredients may be varied in practice according to
the qualities desiderated in the compound, but by way of example it may be
stated that a compound extremely well suited amongst other things for
cutting and other tools is made with the proportions herein-after stated,
namely, with one hundred pounds of pig iron, fifteen to twenty-five pounds of
marine shells in the preparatory process; in the compounding process about
one pound of a mixture of equal parts of rock salt and borax, fifteen to
twenty-five pounds of tin, and about a quarter of a pound of iodine or bromine
mixed with from one to two pounds of manganese, or antimony, or of either of
their oxides, and in the remelting or finishing process from one to two pounds
of a mixture of equal parts of tartar and cream of tartar. The compound
made in this way possesses the important advantages that it may be cast into
the shape of the tool or other article required, that it requires no forging or
hammering, and that it requires no tempering. The tools or articles made of
the compound are finished or surfaced simply by grinding on a stone. A
valuable property possessed by the improved metallic compounds or some of
them is their power of withstanding the corrosive action of strong acids; and
this property renders them very suitable for a number of obvious uses.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Andrew Linmere Dowie in the Great Seal Patent Office
on the 16th November 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ANDREW
LINMERE DOWIE, of Glasgow, in the County of Lanark, North Britain, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventeenth day of May, in the year of our Lord One
thousand eight hundred and sixty-seven, in the thirtieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the
said Andrew Linmere Dowie, Her special licence that I, the said Andrew
Linmere Dowie, my executors, administrators, and assigns, or such others as I,

page_text: the said Andrew Linmere Dowie, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and at all
times thereafter 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 TREATING IRON TO OBTAIN METALLIC COMPOUNDS FOR VARIOUS
USES," upon the condition (amongst others) that I, the said Andrew Linmere
Dowie, my executors or administrators; by an instrument in writing under my,
or their, or one of their hands and seals, should particularly describe 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 Seat Patent
Office within six calendar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said Andrew Linmere Dowie, do hereby
declare the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement in writing, that is to say:-
My said Invention has for its object to obtain various metallic compounds
having iron as the chief ingredient, and possessing various properties of great
value in many useful applications.
In practically carrying out my Invention the iron may either be kept in a
melted state throughout the entire process, excepting the final remelting, or
it may be subjected to repeated meltings constituting separate stages in the
process. The fuel employed may be charcoal, coke, or other fuel ordinarily
used for melting iron.
I effect my improvements principally by adding to or mixing. with the
melted iron various substances, and in herein-after detailing by way of example
several modifications of my improved processes, I shall name certain sub-
stances which I prefer to use, but I desire it to be understood that for such
substances any others may be substituted that are known to, have similar
properties and actions.
Hitherto great difficulty has been experienced in endeavouring to properly
purify iron, and more especially to remove or discharge the sulphur and
carbon, and enable it to form alloys with other metals. By the first and most
important part of my Invention, however, the iron is prepared or treated in
such a way as to adapt it for combining or becoming alloyed with other
metals or alloys with great facility; and with such prepared iron a great
variety of alloys or compounds may be formed, each possessing peculiar.
properties adapting it for particular uses.

page_text: One way of carrying out my Invention is to form a stock metal suitable
without further treatment for some uses, but which having been prepared with
such a view may at any time be remelted with any suitable metal or metals to
form a particular alloy.
I now proceed to detail one modification of processes for forming such a
stock metal as an example of my improvements.
Example 1.-I take a convenient quantity of the best Gartsherrie or
Coltness iron or similar iron and put it into a cupola furnace along with fifteen
to twenty per cent. (by weight) of oyster or other marine shells mixed up in
the ordinary way with the fuel in use for smelting purposes. If iron of inferior
quality is used there should be added two cent. of, rock salt, or five to ten
more of the shells; but if hæmatite iron is used ten to fifteen per cent. of the
shells will be sufficient. Hæmatite ore may be used instead of iron, in which
case there should be twenty per cent. of shells and five of rock salt (added in
the cupola), and two of carbonate of potassium should be stirred into the
metal after it is tapped. When the metal is thoroughly melted I tap it, and
I cast it into bars in moulds, and afterwards remelt it in an air furnace or in
crucibles; or it may be directly run into an air furnace or into crucibles; and
to this partly prepared metal I add an intimate mixture of rock salt and
borax, one quarter per cent. of each, and five of tin, and five of blister steel
or malleable iron. Where salt has been used before, I add by preference one
quarter per cent. of nitrate of strontium or of calcium, and one quarter of
borax ground up together. The mixture of rock salt and borax may be
added all at once before the metals, or one-half of it before and the other half
after the metals. Thirty minutes thereafter the metal is to be stirred and
skimmed, and I then add an intimate mixture consisting of one to two
sixteenths per cent. of iodine and a half to one per cent. of oxide of man-
ganese. Bromine or chloride of iodine may be substituted for the iodine, and
manganese, antimony, or oxide of antimony may be substituted for the oxide
of manganese. In some cases two per cent. of antimony may be added at this
stage or even at the preceding stage, and in such cases the tin or blister steel
or both may or may not be omitted. The contents of the furnace or crucibles
are next brought to a white heat, and after being maintained thereat for from
twenty to twenty-five minutes the metal is cast into bars; these bars are remelted
with one-eighth per cent. of a mixture of equal parts of tartar and cream of tartar,
such mixture being thoroughly mixed or stirred (as all the chemicals should
be) with the melted metal, which is then maintained at a white heat for
about thirty minutes. The metal thus treated may be cast into moulds to
shape it for various uses, it being suitable, for example, for shot cylinders,

page_text: pistons, bearings, and various parts of machinery; or it may be cast into bars
to serve as a stock metal to receive other metals in alloy, or to receive further
portions of any already contained in it. When alloying the stock metal with
additional metals the mixture of tartar and cream of tartar must be added on
the metal being remelted in the proportion of one ounce to every five pounds
of metal thus added to the stock metal, or a mixture of two parts nitrate of
potassium to one of borax may be added instead of the said mixture and in
the same proportions.
I will now in further examples point out some of the modifications that may
be made in my processes.
Example 2. In place of one-half of the shells noted in Example 1 I use
ten per cent. of limestone or lime, one-half of carbonate of potassium, and one-
half of carbonate of sodium; the metal being thoroughly melted I tap it and
cast it into bars for further treatment; on being remelted, or if transferred directly
from the cupola to an air furnace or crucibles, I add one quarter per cent. of
nitrate of sodium and one quarter of borax, mixed up together, and in fifteen
minutes after being brought to a white heat I cast it into small bars in moulds.
Example 3. Instead of the whole of the shells noted in Example 1 I use
from ten to twenty per cent. of limestone, lime, baryta, or strontia, with
five per cent. of rock salt, and two per cent. of carbonate of potassium, which
are to be put into the cupola or air furnace along with the iron and fuel.
If the iron is first melted in a cupola, I add to it after it has been cast
into bars and remelted in an air furnace or in crucibles one per cent. of
an intimate mixture consisting of one per cent. of nitrate of potassium
and a half per cent. of nitrate of barium ground up together; the mixture
should be stirred into the metal when in a thoroughly melted state. The
remainder of the operations may be conducted as in Example 1, or as herein-
after described. Small quantities of metal may be treated throughout in
crucibles, the metal being properly skimmed and cast into bars in moulds at
each stage, or allowed to partially cool and then returned to the furnace, but
in dealing with large quantities it will be most convenient to employ a cupola
for the first melting with shells or limestone, and to use an air furnace for the
subsequent treatment, and such air furnace should be formed with openings
and covers at the top for the introduction of the various chemicals or ingre-
dients, and with other openings in convenient positions for the introduction of
tools for stirring and skimming the metal with.
Example 4. Having prepared the metal so far as in any of the preceding
examples I add a mixture of rock salt and borax, as in Example 1, and in
fifteen minutes thereafter a mixture consisting of from one to two-eighths per

page_text: cent. of iodine, bromine, or chloride of iodine, and from one to two per cent.
oxide of manganese, manganese, oxide of antimony, or antimony; after adding
these things the metal is maintained at a white heat for about thirty minutes,
and may then be cast into bars or into moulds to form articles for use.
Example 5. Instead of continuing the treatment of the iron with the
mixture containing iodine or the like, as in Example 4, the treatment with a
mixture containing nitrate of potassium and nitrate of barium, as in Example 3,
may be repeated a second time, or oftener if found desirable, the metal being
cast into bars, and being remelted between each repetition. Old or scrap iron
may be used along with the iron; or old or scrap iron may be used alone.
Also what has been described herein-before as the first part of my improved
processes may in some cases be omitted or partly omitted, but in those cases
I prefer to modify the rest of the processes to compensate more or less for such
omission. Thus instead of first treating iron with shells or their substitutes
I take melted iron as ordinarily prepared for casting, and treat it as in the
three following examples, and I may mention that such treatment is also
suitable for old or scrap iron.
Example 6. The melted iron is run into a crucible which is placed in a
furnace, and is not allowed to cool. I stir into the metal one per cent. of rock
salt and one per cent. of carbonate of potassium ground up together. In
fifteen minutes thereafter I stir in one quarter per cent. of nitrate of potassium
and one-eighth of pearlash ground up together; at this stage I add the metal
or metals I wish to alloy with the iron, and after maintaining it at a white
heat cast it into bars or moulds. Sometimes the metal may be very much
improved by repeating these operations a second time or oftener.
Example 7. The metal is first treated as in Example 6, and being re-
melted or not having been cooled I stir in one-eighth per cent. of rock salt
and one-eighth borax ground together; in fifteen minutes thereafter the
metal having been stirred and skimmed I add an intimate mixture, consisting
of one-eighth per cent. of iodine or its substitute and one of oxide of
manganese or its substitute for every twenty per cent. of metal alloyed, or
to be alloyed with the iron.
Example 8. To the metal in a melted state in an air furnace or crucible
1 add ten per cent. of marine shells, which should be dried and bruised and
be stirred into the metal, particularly when it is in a crucible. On the sub-
sidence of the ebullition which occurs, and supposing tensile strength to be
wanted, I add five to ten per cent. of scrap or blister steel and malleable iron
with two of antimony. If the metal is in a crucible I prefer to add the steel
or iron in the form of turnings along with the antimony. I maintain the

page_text: metal at a white heat for thirty minutes, and stir and skim it, and then add
one per cent. of rock salt and one of carbonate of potassium ground up
together; I next add fifteen per cent. of tin if I intend the metal for tools,
or other quantities or metals according to the intended use; in fifteen
minutes thereafter I add, ground together, one-sixteenth per cent. of nitrate
of potassium and one-sixteenth of borax for every five per cent. of metal
alloyed with the iron; I maintain the compound at a white heat for thirty
minutes, and then cast it into bars. This metal I remelt for making tools, or
for large or small castings of any kind, and stir in three-sixteenths per cent. of
a mixture of tartar and cream of tartar, together with one to two sixteenths
each of pearlash and of prussiate of potassium if hardness is wanted. Finally
it must be maintained at a white heat for fifteen minutes, being well stirred
and skimmed. Nitrate of sodium, or of strontium, or of barium may be sub-
stituted for the nitrate of potassium, or vice versâ, in any of the preceding
examples, and scrap tinned iron plate may be advantageously used along with
or instead of the blister steel or malleable iron.
I will now proceed to describe a few of the various alloys that may be
formed with my prepared metal, premising that when the stock metal herein-
before described is taken, or a prepared metal having already in it any of the
metal proposed to be alloyed with it, so much less of such metal must be taken.
Example 9. The prepared metal melted with ten to fifteen per cent. of
tin is suited for ordinary cutters for machine tools.
Example 10. Twenty to twenty-five per cent. of tin melted with the
prepared metal give a metal suitable for finer machine tools and edge
tools.
Example 11-Six to ten per cent. of blister steel or malleable iron melted
with Example 9 or 10 give increased strength.
Example 12. Fifteen per cent. of tin and three per cent. of copper alloyed
with the prepared metal make it suitable for some kinds of cutting tools when
toughness is required, also for bells and other articles.
Example 13. A good bell metal is obtained by alloying together one
hundred pounds of the prepared iron, twenty pounds of tin, and twenty of
copper. Bells having different sounds can be produced of the same size and
out of the same moulds by alloying with the prepared iron quantities ranging
from five to fifty per cent. of an alloy of equal parts of tin and copper.
Example 14. A metal capable of resisting the action of acids and con-
sequently suitable for many special uses in which acids are present is formed
by alloying with the prepared metal thirty to fifty per cent. of tin. For this
anti-acid alloy I prefer to have the iron prepared as in. Example 2, manganese

page_text: or antimony being used in preference to their oxides. In some cases also
small quantities of the precious metals may be advantageously used in forming
anti-acid alloys.
It is an important advantage of the alloys herein-before described as
suitable for cutting tools that they may be cast into the shape of the tool,
that they require no forging or hammering, and that they require no tempering.
The tools made of such alloys are finished or surfaced simply by grinding on a
stone. It is, however nevertheless, to be understood that some of my improved
compounds are susceptible of being tempered in the ordinary way in which
common steel is tempered.
These alloys or compounds should be cast into bars and be afterwards re-
melted, and be well stirred with from one-half to one per cent. of a flux, or
mixture of equal parts of tartar and cream of tartar, and this mixture may
be added at once, or in portions at intervals, or the alloy may be remelted
oftener, particularly when the proportions of the added metals are large, a
portion of the mixture being added at each remelting. In remelting the
alloys or compounds borax may in some cases be included in the mixture, then
added, particularly when copper enters into the compound, and hellebore may
be used alone or along with the tartar and cream of tartar when a large pro-
portion of tin is used, as in making the anti-acid metal, as in Example 14.
When two or more other metals are to be alloyed with the prepared iron I prefer
to have such other metals melted or alloyed together beforehand. When casting
the metal into bars, as herein-before frequently mentioned, I prefer doing it
by running the metal into angular moulds made in sand, and when this is
done impurities may frequently be detached from the bottom of the bar,
leaving the body pure and clean.
I would here observe that the advantages forming the object of my Inven-
tion or some of them may be obtained by taking the various substances it is
intended to employ with the view of obtaining any particular quality of metal,
and adding to the iron or mixing therewith the whole of such substances at
one operation. On the other hand a few only of the substances may be used,
the metal being frequently remelted and its treatment with them repeated;
but I believe that such modes of treatment will involve greater expence
and uncertainty than those of which I have herein-before given numerous
examples.
What is herein-before termed prepared iron, or what is termed stock metal,
or any of the alloys or compounds of prepared iron with other metals or alloys,
may be used for large castings (as well as for small ones), and when using it
for large castings it may be melted and treated just as is ordinary cast iron,

page_text: excepting that a portion of charcoal is by preference used along with the
ordinary fuel.
Iron treated according to the first part of my processes, that is to say, with
marine shells or their equivalent, or according to that and other parts of my
processes, but without having other metals alloyed therewith, forms what may be
termed varieties of improved cast iron, (that is, a compound consisting
principally of iron and carbon, or of iron and a substance or substances
replacing the carbon,) which may be used like ordinary cast iron, or other-
wise. It is also to be understood that the various alloys or metallic com-
pounds herein-before referred to are suitable for various uses besides those
indicated by way of example, and various other alloys besides those described
may be made with iron prepared or treated by my improved processes. Some
metals however will not form good alloys with the iron, such as lead, zinc, or
bismuth, unless placed in the cupola at first with the iron and shells, and
these can only be used in small quantities, say, from one to two per cent.,
whilst other metals may be too expensive for general use. When in treating
a charge of iron it is intended to form the whole of it into an alloy with one
particular metal, such as tin, for example, the tin or other metal may be
added before the treatment with rock salt and borax, or partly before and
partly after such treatment, care being taken to keep the metal in a melted
state.
Having thus particularly described my said Invention, and examples of the
various modes in which the same may be performed, I have to state that I
do not restrict myself to the precise details herein-before described; but that
what I believe to be novel and original and claim as the Invention secured
to me by the herein-beforo in part recited Letters Patent is, the treating of
iron to obtain metallic compounds for various uses, substantially in the.
manner herein-before described.
In witness whereof, I, the said Andrew Linmere Dowie, have hereunto
set my hand and seal, this Fourteenth day of November, in the year
of our Lord One thousand eight hundred and sixty-seven.
A. L. DOWIE.
(L.S.)