AN IMPROVED PROCESS FOR THE TREATMENT OF THE SLAG FORMED IN THE DEPHOSPHORISATION OF IRON
Year: 1884

page_text: I, EMIL CAPITAINE, of 89 Chancery Lane in the County of Middlesex, Engineer,
do hereby declare the nature of the said invention for "AN IMPROVED PROCESS
FOR THE TREATMENT OF THE SLAG FORMED IN THE DEPHOSPHORISATION OF IRON
to be as follows:-
"
The phosphoric slag formed in the dephosphorisation of iron is difficult to treat
for the reason that it contains a large excess of bases which in the processes
hitherto employed absorb large quantities of muriatic acid that are not again
recovered.
I have now discovered that the phosphoric slag liberates the ammonia from
ammoniacal salts, in the form of gas just as line does; I utilise this discovery in
such manner that I employ phosphoric slag in the place of lime in the ammonia
soda industry and in all cases where lime is or may be used for the liberation of
ammonia.
The apparatus ordinarily employed for this purpose may also be employed when
phosphoric slag is used therefor. Upon the introduction of the phosphoric slag
into the ammoniacal lye a brisk liberation of the ammonia at once takes place
accompanied by considerable heat. It is preferable that this operation should be
conducted in a series of apparatus in one of which the phosphoric slag when almost
completely used up is boiled with fresh ammoniacal lye, whilst on the other hand
the boiled lye nearly free from ammonia is boiled with fresh slag so as to get the
whole of the ammonia. The slag is employed in a raw state; it is advisable to
break it up into small pieces to enable the ammonia to be more speedily liberated;
during the process the pieces become completely disintegrated.
When the phosphoric slag is so exhausted as not to give up any more ammonia,
the excess bases that it had contained pass into solution as chlorides or as salts
corresponding to the ammoniacal salts. When the treatment of the phosphoric

page_text: slag is effected by the dry process (by roasting) the salts formed out of the excess
bases of the phosphoric slag are removed by lixiviation.
The residuum slag still contains the whole of the phosphoric acid the percentage
of the contents of which after the separation of the bases decomposed in the
solution, will have become doubled or trebled according to the composition of the
original slag.
In the further treatment of this enriched and purified material no difficulties aro
met with; it may be utilised direct as manure or as material for the manufacture
of superphosphate, etcetera.

page_text: COMUMIE DE EVITATIO
"
I, EMIL CAPITAINE of the firm of Capitaine & von Hertling of 89 Chancery
Lane in the County of Middlesex Civil Engineer, do hereby declare the naturo
of my said invention for "AN IMPROVED PROCESS FOR OBTAINING PHOSPHORIC ACID
FROM THE SLAG FORMED IN THE DEPHOSPHORISATION OF IRON a communication
to me from abroad by M. Nahnsen of Schönebeck-an-der-Elbe in the German
Empire, Chemist, and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :—
The phosphoric slag formed in the dephosphorisation of iron is difficult to treat
for the reason that it contains a large excess of bases, which, in the processes
hitherto employed, absorb large quantities of muriatic acid that are
not again
recovered.
I have now discovered that the phosphoric slag liberates the ammonia from
ammoniacal salts in the form of gas, just as lime does; I utilise this discovery.in
such manner that I employ phosphoric slag in the place of lime in the ammonia-
soda-industry and in all cases where lime is or may be used for the liberation of
ammonia.
The apparatus ordinarily employed for this purpose may also be employed when
phosphoric slag is used therefor. Upon the introduction of the phosphoric slag
into the ammoniacal lye a brisk liberation of the ammonia at ouce takes placo
accompanied by considerable heat. It is preferable that this operation should bo
conducted in a series of apparatus, in one of which, the phosphoric slag when almost
completely used up is boiled with fresh ammoniacal lye, whilst on the other hand
the boiled lye nearly free from ammonia is boiled with fresh slag so as to get the
whole of the ammonia. The slag is employed in a raw state; it is advisable to
break it up into small pieces to enable the ammonia to be more speedily liberated;
during the process the pieces become completely disintegrated.
When the phosporic slag is so exhausted as not to give up any more ammonia,
the excess bases that it had contained pass into solution as chlorides or as salts
corresponding to the ammoniacal salts. When the treatment of the phosphoric
slag is effected by the dry process (by roasting) the salts formed out of the excess
bases of the phosphoric slag are removed by lixiviation.
The residuum slag still contains the whole of the phosphoric acid, the percentage
of the contents of which, after the separation of the bases decomposed in the
solution, will have become doubled or trebled according to the composition of the
original slag.
For the further treatment of this enriched and purified material no difficulties
are met with; it may be utilised direct as manure or as material for the manufacture
of superphosphate, etcetera,

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. The treatment with ammoniacal salts or with other substances which give off
ammonia in the presence of alkalies, of slag containing phosphorous, for the
purpose of causing the evolution of ammonia and for the purpose of removing
the excess bases from the slag containing phosphorous substantially as herein before
described.
2. The application of slag treated in the manner described, as manure, direct, or
after disintegration of the same, substantially as set forth.