IMPROVEMENTS IN THE MANUFACTURE OF IRON
Year: 1868

page_text: PROVISIONAL SPECIFICATION left by Carl Friedrich Claus at the
Office of the Commissioners of Patents, with his Petition, on the
30th March 1868.
I, CARL FRIEDRICH CLAUS, of Middlesbrough-on-Tees, in the County
of York, Chemist, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE MANUFACTURE OF IRON," to be as follows:-
In order to manufacture a crude or pig iron of superior quality from
ores containing phosphorus and sulphur, such (for instance) as the oolitic
ores of Cleveland, I propose :-
Firstly. To grind or pulverise the iron ore and grind or pulverise a
good coking coal as well as the limestone or lime intended for the charge
of the furnace, and then to mix these materials together ultimately
in such proportion as may be found necessary, according to the nature
of the iron ore employed.
Secondly. I propose to add to this mixture such substances or
chemicals as are known or may be found capable of expelling by the
application of heat (in connection with the above mixtures) phosphorus,
sulphur, or other impurities which may be contained in the ore, lime-
stone, or coal, either by volatising or otherwise eliminating the same,

page_text: As
I add the chemicals in such proportions as may be required by the
indicated percentage of phosphorus and sulphur in the materials.
substances suitable for that purpose I propose the chlorides of
manganese, calcium, iron, also those of barium, sodium, magnesium,
and the like. I also propose to use oxide or peroxide of manganese,
and I employ the above-named substances either singly or in mixtures
of two or more of the same, for instance, as they exist in the refuse
liquors of the manufacture of chlorine. I prefer, however, the chloride
of calcium and the chloride of manganese, and as a source of the latter
I use the refuse liquors of the manufacture of chlorine.
The application of some of these substances in the manufacture of
iron generally forms no part of my Invention, but only in the manner
described herein.
Thirdly. I subject the mixed materials named in the first section of
this Specification, with or without the additions named in the second
section, to the operation of coking in any of the contrivances employed
for that purpose (such as coke ovens), by which operation they all
become as it were "fused together," forming a conglomerate hard
enough for the subsequent operation of smelting. During the operation
of coking by the heat generated thereby and by the action of the
gases from the coal and the chemical substances (named in Section
No. 2), if such had been added the phosphorus and sulphur of the
raw materials are expelled in the form of volatile compounds of these
impurities which escape along with the coal gases.
Fourthly. The waste gases from the blast furnace when the same
has been charged with a charge containing chlorides, as described above,
are mixed with muriatic acid gas, volatile chlorides, and the like,
and in order to free the gases from the same and to utilise these sub-
stances I pass the waste gases before using them for heating purposes
through lime (in a lime kiln for instance). The lime absorbs the
muriatic acid and becomes converted into chloride of calcium. The
chloride of calcium thus obtained I use again for mixing with the other
materials composing the charge of the blast furnace. If with the
raw materials thus treated I now charge and work the blast furnace
in the usual way I expect to obtain as the resulting advantages a
superior iron, a larger production from the same plant, and an economy
of fuel.

page_text: The operation and processes I have described in the first, second, and
third sections of this Specification in reference to iron ores containing
phosphorus and sulphur, I propose to adopt when mill cinders or
other refuse of the puddling furnaces, or the rolls form the raw materials
for the manufacture of iron.