IMPROVEMENTS IN THE MANUFACTURE OF ARTIFICIAL MARBLE. " OR SIMILAR MATERIAL
Year: 1883

page_text: LETTERS PATENT to Jacob Heinemann of Hannover, German Empire for an
Invention of "IMPROVEMENTS IN THE MANUFACTURE OF ARTIFICIAL MARBLE.
"
OR SIMILAR MATERIAL. a communication to him from Dr Herman Rothe,
Chemist of Hannover, German Empire
PROVISIONAL SPECIFICATION left by the said Jacob Heinemann at the
Office of the Commissioners of Patents on the 23rd July 1883.
"
IMPROVEMENTS IN THE
JACOB HEINEMANN, of Hannover, German Empire
MANUFACTURE OF ARTIFICIAL MARBLE OR SIMILAR MATERIAL" [A communication
to him from Dr Herman Rothe, Chemist of Hannover, German Empire]
This Invention relates chiefly to the conversion of gypsum into marble.
Frequent experiments have been heretofore made with a view to converting
Most of
natural gypsum into marble by a chemical process, but without success.
the said experiments consisted in heating the object manufactured from the said
gypsum to about 300° celsius in order to expel the water of crystallization and
afterwards to impregnate the object thus desiccated, with chemical substances in
such a manner as to cause it to acquire the colour and structure of marble. By
this treatment the gypsum loses its tenacity whilst the water of crystallization
which is expelled leaves open pores behind it so that the object treated in this
manner soon becomes worthless.
According to the present invention I am enabled to obviate the defects of the
above described process. I heat the object manufactured from gypsum to a
temperature of from 100 to 120 degrees celsius in order to expel a part of the
water of crystallization. I subsequently dip the said object in a concentrated
solution of chloride of calcium. When the object is saturated with the said
solution it is removed and dipped into a hot concentrated solution of sulphate of
magnesia. This causes the formation of sulphate of lime within the gypsum which
takes the place of the water of crystallization previously expelled by heat. The
object thus treated becomes thicker and more tenacious and offers considerable
resistance to blows or shocks of any kind.

page_text: The chloride of magnesium formed in this treatment is removed by placing the
said object in water.
The above process is repeated several times, the object being re-heated and
again saturated with chloride of calcium, and treated with sulphate of magnesia.
Each time the heating is repeated, the temperature may be raised until at last it
reaches 400° celsius. The extent to which the temperature may be raised depends
upon the objects which are being treated, those that have been manufactured for
some time being subjected to a higher temperature than those that are treated
immediately after their manufacture.
After the objects have been thus brought in readiness for the impregnation by
chemical substances, I treat the same alternately with solutions of gelatine and
tannin each time for a period of from one to four days according to the size of, the
object the said object being subsequently dried at a suitable temperature in a
drying stove.
Instead of using gelatine other substances may be employed if they form with
desiccated sulphate of lime combinations that are insoluble in water, such as liquid
gluten, the serum of blood, dried oils and the like.
In order to produce colored marble I mix with the solution of chloride of
calcium, metallic chlorides, which on being further treated with metallic salts form
coloured and insoluble precipitates which take the place of the water of crystal-
lization expelled. If for instance chloride of iron is added to the solution of
chloride of calcium, the mixture being further treated with chromate of potash a
brown and insoluble precipitate of chromate of iron and perhaps of lime, is obtained,
with the separation of chloride of potassium. The last stage of the process is
analogous to that above described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Jacob Heinemann in the Patent Office on the 22nd January
.1884.
"
JACOB HEINEMANN, of Hannover, German Empire, " IMPROVEMENTS IN THE
MANUFACTURE OF ARTIFICIAL MARBLE OR SIMILAR MATERIAL A communication.
to me from Dr. Herman Rothe, Chemist, of Hannover, German Empire,
I
This Invention relates to the conversion of gypsum into marble.
Frequent experiments have been heretofore made with a view to converting.
natural gypsum into marble by a chemical process, but without success. Most of
the said experiments consisted in heating the object manufactured from the said :
gypsum to about 300° Celsius in order to expel its water of crystallization, and;
afterwards impregnating the object thus desiccated with chemicals in such a
manner as to cause it to acquire the color and structure of marble. By this
treatment the gypsum loses its tenacity, whilst the water of crystallization expelled
leaves open pores behind it so that the object treated in this manner soon becomes
worthless.
According to the present invention I am enabled to obviate the defects of the
above described process. I heat the object manufactured from gypsum to a
temperature of from 100 to 120 degrees Celsius in order to expel a part of its
water of crystallization. I then dip the said object in a concentrated solution of
chloride of calcium and when it is saturated with the said solution I remove it and
subsequently dip it into a hot concentrated solution of sulphate of magnesia. This
causes the formation within the gypsum of sulphate of lime, which takes the place
of the water of crystallization previously expelled by heat; the object thus treated
becomes more compact and acquires a more tenacious and resistant nature, whilst
the chloride of magnesium formed is removed by placing the said object in water.
Subsequent to this treatment, the object is reheated, again saturated with a
solution of chloride of calcium and treated with sulphate of magnesia, which
treatment may be several times repeated. Each time the heating repeated, the
temperature may be raised until at last it reaches 400° Celsius. The extent to
which the temperature may be raised depends upon the nature of the material
under treatment, the greater the age of the said material the higher should be the
temperature.
After the objects have been. thus impregnated, I treat the same alternately with
solutions of gelatine and tannin, each time for a period of from one to four days
according to the size of the object, the latter being subsequently dried at a suitable.
temperature in a drying stove.
Instead of using gelatine, other substances may be employed which form, with
desiccated sulphate of lime, combinations that are insoluble in water, such as liquid
gluten, the serum of blood, drying oils and the like; in some cases the gelatinous
substances employed may be combined with the sulphate of lime by means of a
solution of alum.
In order to produce colored marble I mix with the solution of chloride of calcium
such metallic chlorides as will, on being subsequently treated with metallic salts,
form colored and insoluble precipitates, which take the place of the water of
crystallization expelled. If, for instance, chloride of iron is added to the solution
of chloride of calcium, the mixture being further treated with chromate, of potash,
a brown and insoluble precipitate of chromate of iron and of lime is obtained, with
the forination and separation of chloride of potassium. The subsequent treatment
is analogous to that above described.

page_text: Having thus fully described the said Invention as communicated to me and the
manner of performing the same I wish it understood that I claim :-
First. The treatment of objects manufactured from gypsum, by heating the same
and subjecting them to the action of solutions of chloride of calcium and sulphate of
magnesia, substantially as, and for the purpose, set forth.
Second. In the production, of colored marble, the addition to the said solution of
chloride of calcium of such metallic chlorides as will, on being subsequently treated
with metallic salts, form precipitates, which take the place of the water of
crystallization expelled from the gypsum, as above described.
Third. The subsequent alternate treatment of the said objects with solutions of
gelatine and tannin or substances that will form an insoluble combination with
desiccated sulphate of linie, such as gluten, the serum of blood, or drying oils, the
combination of gelatinous substances with sulphate of lime being effected, if desired,
by means of a solution of alum, as above set forth.
In witness whereof I the said Jacob Heinemann have hereunto set my hand
and seal this thirty first day of December in the year of our Lord One thousand
eight hundred and eighty three.