IMPROVEMENTS IN THE MANUFACTURE OF HYDROCHLORIC ACID
Year: 1884

page_text: I ERNEST SOLVAY of Brussels in the Kingdom of Belgium Manufacturer
do hereby declare the nature of said Invention for "IMPROVEMENTS IN THE
MANUFACTURE OF HYDROCHLORIC ACID "
to be as follows:-
My Invention relates to the process of decomposing chloride of calcium by
means of vapour of water in presence of silica or silicious and aluminous
substances.
I have found that when a mixture is composed in such relative proportions that
the chloride of calcium contained therein corresponds to the required theoretical
quantity of silica and alumina a mass is obtained which softens when submitted
to the temperature required to produce reaction, the matter agglomerates and the
apparatus with difficulty continues to work-If more silica and alumina be added,
the desired infusibility is obtained but then the material is no longer suited to the
manufacture of cement nor can it be subjected to any chemical treatment whatever
and the residuum is no longer so basic nor so soft.
I reconcile these two contrary conditions by introducing into the mixture a
sufficient quantity of the residuum of a previous operation which residuum is
infusible at the temperatures required to produce reaction.
The new mixture thus resists heat sufficiently, although it contains quite as
much lime as the mixture made in one single operation and containing the
theoretical proportions of chloride of calcium and of silicious or aluminous
substances.
As regards the silicious material to be used, the only one which, has been
proposed up to the present time is silicious sand but when the difficulties of a
manufacture on an industrial scale are considered it is found that sand is precisely
what is not suited to it-for being granular it does not form with chloride of calcium
a paste sufficiently binding, thus the mixture obtained is more fusible, less homo-
genous and cannot be decomposed completely whilst at the same time it yields a
bad residuum. I have therefore seriously studied this question and made con-
siderable researches to discover what varieties of silica other than sand are suited
to the purpose and I have found that those species known generally as silicious clays
are what ought to be used, such for instance as "Ergeron" and also infusorial silica,
fossil flour or Kieselguhr etc.
I have also found that silica when precipitated chemically is quite suitable for
the process.

page_text: I, ERNEST SOLVAY, of Brussels in the Kingdom of Belgium, Manufacturer,
do hereby declare the nature of my invention for "IMPROVEMENTS IN THE
MANUFACTURE OF HYDROCHLORIC ACID," and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement :-
My invention relates to the process of decomposing chloride of calcium by
means of vapour of water in presence of silica or silicious and aluminous
substances.
:
I have found that when a mixture is composed in such relative proportions that
the chloride of calcium contained therein corresponds to the required theoretical
quantity of silica and alumina a 'mass is obtained which softens when submitted
to the temperature required to produce reaction the matter, agglomerates and the
apparatus with difficulty continues to work. If more silica and alumina be added
the desired infusibility is obtained but then the material is no longer suited to the
manufacture of cement nor can it be subjected to any chemical treatinent whatever
and the residuum is no longer so basic nor so soft.
:
I reconcile these two contrary conditions by introducing into the mixture a
sufficient quantity of the residuum of a previous operation which residuum is
infusible at the temperatures required to produce reaction.
The new mixture thus resists heat sufficiently although it contains quite as
much lime as the mixture made in one single operation and containing the
theoretical proportions of chloride of calcium and of silicious or aluminous
substances.
.
As regards the silicious material to be used the only one which has been proposed
up to the present time is silicious sand but when the difficulties of a manufacture
on an industrial scale are considered it is found that sand is precisely what is not
suited to it, for being granular it does not form with chloride of calcium a paste
sufficiently binding, thus the mixture obtained is more fusible, less homogenous
and cannot be decomposed completely whilst at the same time it yields a bad
residuum. I have therefore seriously studied this question and made considerable
researches to discover what varieties of silica other than sand are suited to the
purpose and I have found that those species known generally as silicious clays are
what ought to be used, such for instance as Ergeron" and also infusorial silica,
fossil flour or "Kieselguhr et cetera.
I have also found that silica when precipitated chemically is quite suitable for
the process.
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 of adding to the mixture a portion of the residuum obtained
from a previous operation for the purpose of communicating to the mixture

page_text: to be decomposed. sufficient infusibility without diminishing its basic properties
substantially as described.
2. The process of forming the mixture to be decomposed by introducing therein
certain natural or even artificial varieties of silicious substances other than sand
such as silicious clays, "ergeron" infusorial silica or silica when precipitated
chemically.