Method of Preparing Iron Oxides from Ferrous Solutions.
Year: 1889

page_text: Date of Application, 21st June, 1889
Complete Specification Left, 21st Mar., 1890-Accepted, 26th Apr., 1890
PROVISIONAL SPECIFICATION.
Method of Preparing Iron Oxides from Ferrous Solutions.
I, ALEXANDER SYDNEY RAMAGE of Fern Villa, Sankey, County of Lancaster,
Chemist, do hereby declare the nature of this invention to be as follows:-
This invention relates to a method of preparing iron oxides from ferrous solutions.
When air is blown into a ferrous solution in the ordinary manner very little
chemical action occurs, the oxidation taking place very slowly.
In preparing the iron oxides by my method I precipitate the ferrous hydrate or
carbonate with milk of lime or other alkaline earths, sodium carbonate or other
alkalies, and at the same time blow air through the solution.
While in the nascent state the ferrous hydrate takes oxygen from the air in a way
that, under other conditions, it will not do. The oxide is thereby rendered capable
of forming the higher shades of colours, that is, those which have hitherto produced
higher prices.
Dated this 90th day of luno 1880
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicant.
COMPLETE SPECIFICATION.
Method of Preparing Iron Oxides from Ferrous Solutions.
I, ALEXANDER SYDNEY RAMAGE of Fern Villa, Hough Green, Widnes, in the
County of Lancaster, 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:-
It has been known for a long time past that if a solution of almost any salt of
iron be treated with lime, a precipitate of hydrate will take place, ferrous or ferric
according to the salt employed. Also, that ferrous hydrate roasted will produce a
dull red pigment. A brighter red pigment, iron oxide scarlet, is found in nature in
some places, but no means of producing it artificially has yet been found.
Now by my invention, I produce a remarkably brilliant red oxide same as the
natural scarlet, and also one commonly known as Indian red.
The mode in which I accomplish this is as follows :-
By an oxidising agent such as air blown in or bleaching powder, I partially convert
the ferrous solution into a ferric one. At the same time gradually (or afterwards in
any manner) I add lime and thus precipitate the iron as a ferroso ferric hydrate
having substantially the proportion one third by weight, ferric hydrate, calculated
as Fe, O, and two thirds ferrous hydrate, calculated as Fe O. I now filter press
this hydrate, preferably in Brock and Minton's new patent press, and when well
pressed thoroughly wash out all calcium chloride. A trace of this renders the shade
afterwards dull and gives off obnoxious fumes in the furnace. I then furnace the
hydrate in a reverberatory furnace with a limited supply of air, so as to have a
reducing flame.
The following are the particulars of a furnace actually constructed and at work
and giving a good performance.
Reverberatory furnace of ordinary construction, bed 14 feet by 8 feet, charge
about 3 tons of oxide. It is kept at a cherry red heat for about four hours according
to richness of shade, the fire being very deep so as to produce a large excess of
carbonic oxide. From time to time during the roasting, the damper is closed, the
door opened just sufficiently to work, and the whole charge well stirred with a rake
ID 877

page_text: or other tool. The material is now drawn from the furnace and at once plunged into
water, ground and dried. This produces the Indian red. For the scarlet, furnacing
only lasts about 2 hours.
It will be obvious that in place of oxidising a ferrous solution till one third is
oxidised into the ferric state, I could use a mixture of one third ferric and two
thirds ferrous salt at start, also that in place of lime, other alkaline earth or alkali
would do, but these are all more expensive than lime, and, in the case of the alkaline
earths, have a higher combining equivalent and difficult solubility, both very objection-
able points, and I merely mention these facts as in practice only lime will be used,
but while using the word lime, I wish it to be understood that I include the other
hases referred to, namely, potash, soda, ammonia, strontia, baryta and magnesia.
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 process of making a brilliant red, also an Indian red pigment, which consists
in oxidising a ferrous solution till about one third of the mass is in the ferric state,
precipitating with lime, and furnacing the precipitate in a reducing flame at a bright
red heat.
2. The process of making a brilliant red or Indian red pigment, which consists in
forming a hydrated precipitate of a ferroso, ferric oxide approximately one third
ferric to two thirds ferrous and furnacing the same in a reducing furnace with
occasional stirring.
3. The improvement in the process of making a ferroso ferric oxide pigment,
which consists in roasting the ferroso ferric hydrate at a bright red heat in a reducing
furnace, that is, in a furnace the hearth of which is largely charged with combustible
gas, such as carbonic oxide.
.
Dated the 20tL
1000
WM. P. THOMPSON & Co.,
Of
Of Liverpool, Manchester, and London, Patent Agents.