Improved Process for Facilitating the Disintegrating of Thomas-slag.
Year: 1894

page_text: Date of Application, 11th Dec., 1894-Accepted, 17th Aug., 1895
COMPLETE SPECIFICATION.
Improved Process for Facilitating the Disintegrating of Thomas-slag.
I, EMIL MEYER, Doctor of Philosophy, of 42 Lessingstrasse, Berlin, in the
Kingdom of Prussia, German Empire, do hereby declare the nature of my
invention and in what manner the same is performed to be particularly described
and ascertained in and by the following statement:-
The value of Thomas-slag for manuring purposes depends partly upon the
fineness of the powder employed and partly upon the amount of phosphoric acid
contained in the same, and then again on the particular state or chemical
combination in which the phosphoric acid is present in the manure. By means of
the process herein after described, the reduction or disintegration of very hard
slag is greatly facilitated and the chemical disintegration of the phosphoric acid by
ignition with alkaline carbonates and the like is greatly enhanced.
To the fluid Thomas-slag is added a small quantity of alkaline carbonate, either
at once or whilst the casting from the converter is taking place, the said carbonate
dissolving evenly in the mass and producing the above mentioned favorable effect.
The effect is, however, still more increased by employing alkaline silicate in the
same manner, which is less volatile and assists the chemical disintegration more on
account of its more powerful action on the lime. An addition of 5 to 15 parts of
silicate of natrium (waterglass) to a hundred parts of Thomas-slag, which
according to the more or less alkaline nature of the said silicate entirely dissolves
in the fluid slag, will effect a still more favorable disintegration of the slag. If
soda is employed instead of waterglass, which latter must of course be free from
With certain
water when added to the slag, half the quantity will be sufficient.
kinds of slag an addition of less than 5% of waterglass will be sufficient to reduce
the partially insoluble phosphoric acid of the slag to the so called citrate-soluble
form. The addition of the reducing substances is as a rule still less, as the effect
of the same is exercised on the ferric oxide, which is changed to protoxide of iron-
lime-waterglass, which renders the phosphoric acid soluble, contrary to such slags
as contain oxide of iron.
The effect of the alkaline silicate is still further increased if substances are
mixed with the same, which combine easily with oxygen and thus convert the
more highly oxidised combinations contained in the slag, particularly ferric oxide
into ferrous oxide combinations. Coke powder, or metallic sulphides, particularly
white iron pyrites or sulphide of sodium-which latter often forms an impurity of
waterglass are well adapted for such reducing purpose. The proportion of the
metallic sulphides added is about 15% to 18% of the metallic iron contained in
the slag in the form of ferric oxide. As the slag contains about 5% to 7% of
such ferric oxide about -75% to 1.26% of the slag or in round numbers 1% of
the slag, should be added i.e. 1% of metallic sulphide should be added.
sulphur in these reducing agents combines with the lime in the fluid slag, the
carbon escaping as carbonic oxide. The heat produced by this combustion.
increases the action of the chemical combination. The proportion of the reducing
substances added should be about 8 to 20 parts of carbon for each 100 parts of
metallic iron, dissolved in the slag in the form of ferric oxide.
The
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 A process for facilitating the chemical and mechanical disintegration of

page_text: Thomas-slag, consisting in introducing into the same, whilst in a fluid state
alkaline carbonate or silicate, in the manner substantially as described.
2. A process for facilitating the chemical and mechanical disintegration of
Thomas-slag, consisting in first introducing into the same, whilst in a fluid state,
alkaline carbonate or silicate and then adding further a reducing powder to the
same, such as coke, metallic sulphide,, white iron pyrites or their equivalents
substantially as described.
Dated this 11th day of December 1894.
HASELTINE, LAKE & Co.,.
45 Southampton Buildings, London, W.C., Agents for the Applicant.