IMPROVEMENTS IN THE MANUFACTURE OF IRON
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Peter Louis Tischbein von Schöning
at the Office of the Commissioners of Patents on the 8th November 1883.
PETER LOUIS TISCHBEIN VON SCHÖNING of Vienna in the Empire of Austria,
temporarily of Middlesbrough on Tees in the North Riding of the County of
York, Engineer "IMPROVEMENTS IN THE MANUFACTURE OF IRON
""
My invention has for object the production of pig iron from the blast furnace
free or nearly free from phosphorous when working upon ores containing
phosphrous. To this end I bring the ores in a heated state into contact with
substances capable of forming chemical compounds with phosphorous, which
compounds are removed either in the form of gases or of slag. The union of the
phosphorous with such substances may be effected either in special roasting furnaces,
or in ordinary roasting furnaces, or in the blast furnace itself, or partly in the
roasting furnace and partly in the blast furnace.
My invention may be carried into effect in different ways, depending upon the
local conditions under which it is performed. According to one method I roast
the ores in admixture with basic materials such as alkalies, or alkaline or
carbonaceous earths, limestone, alumina, potash, soda, common salt and the like,
and part of the phosphorous becomes combined with these substances. I also use
in the roasting furnance substances which contain elements of the chlorine group,
and I force superheated steam through the roasted product. When seaweed is
readily obtainable I mix it with the ore and fuel, and while the seaweed serves
also as fuel, its iodine and chloride of soda contents form gaseous compounds with
the phosphorous; the superheated steam also combines with the phosphorous,
forming phosphoretted hydrogen, and all these gases escape. In addition to the
above mentioned substances I employ others which can be conveniently and
cheaply obtained, and which are known to form, either singly or in combination,
gaseous compounds with phosphorous. The limestone also absorbs part of the
phosphoric acid, and a similar result follows the use of minerals containing
manganese. When I use a special roasting furnace I arrange it in such a manner
that the roasted product can be withdrawn from any point in the horizontal section
of the furnace by means of an arrangement of grates and clearing out openings.
Die R71

page_text: The materials which I use to combine with the phosphorous in the blast furnace,
and to carry the same away in the slag are of a basic nature and consequently the
slag will bo basic. Basic slags, however, containing limestone and clay, are deficient
in fluidity, and this difficulty I overcome by adding fluor spar to the charge, which
produces an easily flowing basic slag, and according to the proportion in which it is
used enables a slag of the required consistency to be produced. The same object
may be attained by using materials containing potash or soda, and also by
manganese. By theso means a slag can be produced which is at once basic and of
such consistency as is desirable to protect the reduced and carburetted iron from
the direct influence of the blast, and such as will not injure a basic lining, that is,
one which does not contain much silica. Among the substances containing potash
and soda, and which are available for this purpose, there are, besides numerous
minerals, the soda saltpetre brought from Chili, which has furthermore the effect
of combining the phosphorous and sulphur with the slag during the blast furnace
process. Also the waste produced in grinding glass, which contains large quantities
of alkali. I sometimes also use materials in the blast furnace capable of forming
gaseous compounds with phosphorous, as already described with reference to the
roasting process.
It will be evident that my invention may be carried into effect by the aid of
many different materials which can be readily selected by the expert according to
the local and other circumstances under which the iron manufacture is carried on