Alkalies in the Manufacture of Steel and Iron.
Year: 1885

page_text: Alkalies in the Manufacture of Steel and Iron.
I THOMAS TWYNAM of 110 Grange Road East, Middlesboro, in the County of
York, Analytical Chemist do hereby declare the nature of my said invention for
IMPROVEMENTS IN THE PRODUCTION OF SOLUBLE PHOSPHATES OF THE ALKALIES
IN THE MANUFACTURE OF STEEL AND IRON to be as follows:-
.
This invention relates to the production of soluble alkaline phosphates from the
phosphoric slags, produced in the manufacture of Iron or Steel, when an alkaline
salt has been added, during the conversion of the phosphoric pig metal for the
purpose of eliminating the phosphorus.
It is found that the phosphoric acid contained in these alkaline slags is sometimes
wholly or very largely insoluble in water but by this invention however, this
insoluble phosphoric acid may be readily converted into the soluble form. The slag
which generally consists of oxides of iron and manganese, soda and insoluble
phosphoric acid is treated as follows. I fuse the slag with a sufficient amount of
either an alkaline carbonate, hydrate, or sulphate to render the insoluble. phosphoric
acid contained in it soluble, the amount required of either of these substances for
the purpose is best determined by experiment, as it varies somewhat with the
composition of the insoluble alkaline slag employed.
I have found with slags containing from 15 to 20 % (fifteen to twenty per cent)
insoluble phosphoric acid, that from 50 to 60 parts of carbonate of soda to 100 parts
of slag gives good results. When sulphate of soda is used, 100 parts of sulphate
may be fused with 100 parts of the slag. With richer slags more of the alkaline
salt should be added. The re-action is quickly effected, and it will be found that
the whole or the greater part of the phosphoric acid in the resulting fusion is
soluble in water. Instead of using either of the above alkaline salts I sometimes
fuse the insoluble alkaline slag with excess of alkaline chloride, preferably rabbling
with a steam jet. Or the insoluble alkaline slag, and alkaline chloride may be
formed into bricks with or without admixture with coke dust, the bricks thus
formed being subjected in a suitable chamber to the action of steam the heat being
kept below the fusing point of the bricks. I sometimes also finely grind the
insoluble alkaline slag and boil it in a strong solution of alkaline carbonate or
hydrate with or without pressure.

page_text: Improvements in the Production of Soluble Phosphates of the
Alkalies in the Manufacture of Steel and Iron.
I, THOMAS TWYNAM of 110 Grange Road East, Middlesboro, in the County of
York, Analytical 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:
This invention relates to the production of soluble alkaline phosphates from
phosphoric slags produced in the manufacture of steel or iron when alkaline salt
has been added in the furnace or converter for the purpose of eliminating the
phosphorus during the conversion of the phosphoric pig into iron or steel.
I find that the phosphoric acid exists in these alkaline phosphoric slags largely
or wholly in a form insoluble in water so that the chief object aimed at in the
formation of such alkaline slags is defeated. I overcome this drawback however,
in the following manner :-
The alkaline phosphoric slag which is formed in the furnace or converter (and
in which the phosphoric acid is chiefly in the insoluble form).is mixed with an
additional amount of an alkaline salt for which purpose either the carbonate,
hydrate, or sulphate may be employed, the carbonate however is the alkaline salt.
I always prefer to employ. This mixture may be made either by adding the
alkaline salt in a solid or molten state to the fluid slag, or by mixing the two in a
solid state and subsequently fusing or fritting them together in a basic lined open
hearth furnace or in a small basic lined cupola.
The amount of the alkaline salt necessary to be added is best determined by a
separate estimation of the amount of insoluble phosphoric acid in each slag, there
should be present in the resulting fusion at least two equivalent of soda (Na,O)
to every equivalent of phosphoric acid present. The whole or the greater part of
the phosphoric acid in the resulting fusion will be found to be soluble. In employing
the sulphate an oxidizing atmosphere is required during the fusion and the sul-
phurous fumes given off will have to be condensed. Instead of using either of the
above alkaline salts I sometimes fuse the insoluble alkaline slag, with excess of
alkaline chloride preferably rabbling the fusion with a steam jet or introducing
steam into the cupola in which the fusion is performed. In this case hydrochloric
acid fumes are given off which will have to be condensed.
I sometimes also finely grind the insoluble alkaline slag and boil it in a strong
solution of alkaline carbonate or hydrate with or without pressure.
The soluble alkaline phosphate formed from the insoluble alkaline phosphoric
slag by any of the above means can be dissolved out in water and obtained
practically pure by evaporation and crystallization, or the solution may be treated
in the ordinary way with lime or carbonate of lime to form a phosphate of lime,
the soda being recovered as bydrate or carbonate.
Although sodic salts only are mentioned in the above, the potassic salts may be
equally well employed.

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 process for producing soluble alkaline phosphates from alkaline phosphoric
slags in which the phosphoric acid is wholly or chiefly insoluble, consisting in
treating the insoluble slag by fusion or otherwise, with an alkaline salt by which
the phosphoric acid is converted into a soluble form substantially as set forth.
Dated this 2nd day of March 1886
PHILIP M. JUSTICE,
Applicant's Agent.