Improved Manufacture of Artificial Stone.
Year: 1891

page_text: Date of Application, 2nd Apr., 1891-Accepted, 13th June, 1891
JTON
STREET
COM DIN DE MULLICATION.
Improved Manufacture of Artificial Stone.
A communication from LUDWIG GROTE, Manufacturer, of 10 Oberscergasse,
Dresden, in the Empire of Germany.
, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., 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:-
The object of this invention is the manufacture of a mass of the nature of stone,
which is semi-liquid or plastic while being shaped or moulded but becomes capable
of being turned in a lathe and ground or polished while it is solidfying, i.e. before it
is completely hardened.
The many methods which have hitherto been adopted in manufacturing similar
masses mainly consisted in applying high pressure in moulding and only enabled a
material to be obtained which might be sawn or bored but not turned and polished.
The main advantage of this invention therefore is that the substances to be mixed
and the mixture when ready, are treated in such a manner that no pressure is
necessary in the moulding process, and that the hardening of the mass lasts a certain
space of time which permits the moulded articles to be turned true or polished
before the hardening is complete.
To attain this result cellulose is steeped in an ammoniacal solution of oxide of
copper (kupferoxyd amoniak), and when thoroughly soaked freed from the
superfluous liquid so as to remain in the condition of a thick pulp.
What is known as Sorel's cement (magnesite containing chlorine) may be
employed as filling material the burnt magnesite being mixed with a solution of
chloride of magnesium and chloride of zinc. The pulp thus obtained is dried and
heated in tightly closed vessels the heating being however only kept up long
enough and at a sufficiently high temperature to prevent the escape of more than
an insignificant quantity of the hydrochloric acid so that the mixture remains
saturated with the chlorides. The mass is then ground or otherwise reduced to a
pulverulent condition and mixed with the cellulose in the required proportion a
small quantity viz.-about from 5 to 20 per cent. of alumina being preferably
added.
The almost dry pulp thus obtained is forced into moulds and exposed to the
influence of the air. During the first twelve hours the water rapidly "settles"
and the mass becomes strongly heated. During the succeeding twelve hours it
partly retains its plasticity while at the same time it is capable of being turned or
polished the chips or shavings being of a structure somewhat similar to that of
wood or horn. At the end of the twenty fourth hour the mass will be found so
hard as no longer to be capable of being worked by tools.
The proportions of the ingredients depend upon the nature of the articles it is
intended to produce and more or less cellulose is to be used according as it is desired
to make then resemble more closely wood, horn or natural stone. The following is
an approximate recipe which will be found satisfactory in most cases :-
50 grammes of dried wood pulp steeped in 50 grammes of an ammoniacal
solution of oxide of copper (100 pts. in 500 pts. of water).
1000 grammes (38 p. c.) of chloride of magnesium and
350 grammes (32 p. c.) of chloride of zinc mixed with
500 grammes of burnt magnesite.
Both mixtures are then added to each other in the proportion of about one part
by weight of the "wood" mixture to fram
10

page_text: The novel technical result thus obtained consists in the chemical "settling" of
the water which causes the mass to solidify by such slow degrees as to enable the
mass to be worked into the desired shape before it entirely hardens.
•
Having now, particularly described and ascertained the nature of the said inven-
tion, as communicated to me by my foreign correspondent, and in what manner the
same is to be performed, I declare that what I claim is :-
1. A process of manufacture of a mass partaking of the nature of stone and
capable of being turned in a lathe and polished or ground such process consisting in
mixing cellulose, steeped in an ammoniacal solution of oxide of copper (Kupferoxyd
amoniak) with magnesite rich in chlorine which serves the purpose of filling
material, with a view to effecting the chemical settling" of the water and thereby
bringing about the ultimate solidification of the mass substantially as described.
2. The manufacture of artificial stone substantially as specified.
Dated this Cananil
.1 1001
W. P. THOMPSON & BOULT,
Agents for the Applicant.