Improvements in the Manufacture of Cement and in the Treatment of Articles Cast therefrom.
Year: 1890

page_text: Date of Application. 2nd June, 1890
Complete Specification Left, 28th Feb., 1891-Accepted, 11th Apr., 1891
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Cement and in the Treatment
of Articles Cast therefrom.
I, OTTO PRINZ, of Schwarzenberg i. Sachsen, Germany, Doctor of Philosophy,
do hereby declare the nature of this invention to be as follows:-
:-
Ordinary sorel cement, by which is meant a compound of magnesium oxide with
magnesium chloride and water, becomes separated into its constituent substances
when it is poured into a mould, and it also has two other objectionable qualities
which exclude its use for many purposes viz., it swells and it sweats or becomes
covered with moisture.
Separation into its constituent substances, takes place with all sorel cement
mixtures, with the exception of those for which highly concentrated solutions of
magnesium chloride (over 30° Bé.) are employed, but these mixtures give masses
of small durability.
Swelling is shown in sorel cement that has been poured out, by an increase in
volume taking place a short time after the casting has solidified, and which causes
the vessels and moulds, into which the cement is poured, to burst, and the entire
mass to split.
Under "sweating" is meant the appearance of numerous drops of liquid on the
surface of the hardened sorel cement, and which gradually dry up and leave a white
powder.
By methods hereinafter described sorel cement can be obtained having none of
the disadvantages above referred to.
I have found that the separating of the cement mixture into its constituent
substances and the swelling of the solidified sorel cement, do not take place when
small quantities of gelatinous substances are mixed with the cement.
Suitable substances for mixing with the cement mixture, are:--albumen or white
of egg, glue, gum, dextrine, starch, vegetable mucus, agar-agar, gelatinous silica,
hydrate of alumina, hydrated oxide of iron, and generally all oxides that are
gelatinous.
Of these substances, those that are soluble can be dissolved in the solution of
chloride of magnesium. Gelatinous silica can be produced in the solution itself by
adding thereto a solution of water glass. The gelatinous hydrates of metallic
oxides are produced by dissolving in the solution of chloride of magnesium, a
soluble salt of the metal used and then precipitating the metal as hydrated oxide
either by an addition of a solution of soda, or by the addition of magnesia
produced later on in the process.
To the list of hydrated oxides suitable for use, there also belongs freshly
precipitated hydrate of magnesia which can be produced in the solution of
chloride of magnesium by adding to such solution, a solution of soda, or prefer-
ably by heating the solution or dissolved salt until hydrochloric acid begins to be
given off.
The solution of chloride of magnesium to which one or other of the before
mentioned substances has been added, is then employed in the ordinary manner for
the manufacture of sorel cement.
The sweating of sorel cement is caused according to my experience, by the
action of the carbonic acid in the atmosphere upon the cement, whereby magnesium
carbonate and magnesium chloride are formed.
The liberated chloride abstracts moisture from the atmosphere, and the solution
thus produced appears in the form of drops on the surface of the pieces of cement.
To obviate this drawback of sorel cement as ordinarily made, I artificially hasten

page_text: this action of the carbonic acid, by allowing the cast cement articles to remain in
an atmosphere of carbonic acid until they are saturated with the gas, and then
removing the liberated chloride of magnesium therefrom by placing them in water.
By repeatedly treating cast sorel cement articles alternately with carbonic acid
and with water, all chloride of magnesium can be removed therefrom. The
composition of the remaining mass is represented by the formula Mg. CO³ + 3H2O;
and has about the same strength as ordinary sorel cement. For most purposes
however, a single treatment of the casting with carbonic acid and with water as
described will be sufficient.
Dated this 2nd day of June 1800
OTTO PRINZ,
Per L. W.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Cement and in the Treatment
of Articles Cast therefrom.
I, OTTO PRINZ, of Schwarzenberg i. Sachsen, Germany, Doctor of Philosophy
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 :-
Ordinary sorel cement, by which is meant a compound of magnesium oxide with
magnesium chloride and water becomes separated into its constituent substances
when it is poured into a mould, and it has also two other objectionable qualities
which exclude its use for many purposes viz. it swells and it sweats or becomes
covered with moisture. Separation into its constituent substances takes place with
all sorel cement mixtures with the exception of those for which highly concentrated
solutions of magnesium chloride (over 30 Bé.) are employed but these mixtures
give objects of small durability. Swelling is shewn in sorel cement that has been
poured out by an increase in volume taking place a short time after the casting has
solidified, and which causes the vessels and moulds into which the cement is
poured, to burst, and the entire mass to split. By sweating is meant the appearance
of numerous drops of liquid on the surface of the hardened sorel cement and which
gradually dry up and leave a white powder.
By methods hereinafter described sorel cement may be obtained having none of
the disadvantages above referred to.
I have found that the separating of the cement mixture into its constituent
substances and the swelling of the solidified sorel cement do not take place when
small quantities of gelatinous substances are mixed with the cement. Suitable
substances for mixing with the cement are: albumen or white of egg, gum,
dextrine, starch, vegetable mucus, agar-agar, gelatinous silica, hydrate of alumina,
hydrated oxide of iron and generally all oxides that are gelatinous. Of these
substances those that are soluble can be dissolved in the solution of chloride of
magnesium. Gelatinous silica can be produced in the solution itself by adding
thereto a solution of water-glass. The gelatinous hydrates of metallic oxides are
produced by dissolving in the solution of chloride of magnesium a soluble salt of
the metal used, and then precipitating the metal as hydrated oxide either by an
addition of a solution of caustic soda, or by the addition of magnesia later on in
the process. To the list of hydrated oxides suitable for use there also belongs
freshly precipitated hydrate of magnesia which can be produced in the solution of
chloride of magnesium by adding to such solution a solution of caustic soda, or
preferably by heating the solution or dissolved salt until hydrochloric acid begins
to be given off.
The proportion of gelatinous substance required for the production of the thick
fluid body varies from 1 to 5 per cent. of the weight of the solution used.

page_text: 1 per cent. being sufficient of starch, agar-agar, vegetable mucus and like substances
and up to 5 per cent, when gelatinous hydrated metallic oxides are used.
The solution of chloride of magnesium to which one or other of the before
mentioned substances has been added, is then employed in the ordinary manner for
the manufacture of sorel cement.
The sweating of sorel cement is caused, according to my experience, by the
action of the carbonic acid in the atmosphere upon the cement, whereby magnesium
carbonate and magnesium chloride are formed. The liberated chloride attracts
moisture from the atmosphere and the solution thus produced, appears in the form
of drops on the surface of the pieces of cement.
To obviate this drawback of sorel cement as ordinarily made I artificially hasten
this action of the carbonic acid by allowing the cast cement articles to remain in
an atmosphere of carbonic acid until they are saturated with the gas and then
removing the liberated chloride of magnesium therefrom by placing them in water.
By repeatedly treating cast sorel cement articles alternately with carbonic acid
and with water all chloride of magnesium can be removed therefrom.
composition of the remaining mass is represented by the formula Mg CO, + 3H₂O
and has about the same strength as ordinary sorel cement. For most purposes
however, a single treatment of the casting with carbonic acid and with water as
described, will be sufficient.
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:
The employment of gelatinous substances such as albumen or white of egg, gum,
dextrine, starch, vegetable mucus, agar-agar, gelatinous silica, hydrate of alumina,
hydrated oxide of iron and generally all oxides that are voluminous and gelatinous
as an addition to chloride of magnesium solution for the purpose of the production
of non separating and non swelling sorel cement as also the treatment of sorel
cement articles alternately with carbonic acid and with water for the purpose of
suppressing the sweating of the cement, substantially as described.
Dated this 28th dor of February 1891
CAPITAINE & vox HERTLING,
89, Chancery Lane, London, W.C., Agents for the Applicant.