A Process for Producing Mono-carbonate of Calcium.
Year: 1889

page_text: Date of Application, 9th Mar., 1889
Complete Specification Left, 7th Dec., 1889-Accepted, 18th Jan., 1890
PROVISIONAL SPECIFICATION.
A Process for Producing Mono-carbonate of Calcium.
I, FRANZ MÜHLENBRUCH, of 50 Kaiserstrasse, Magdeburg, in the Empire of
Germany, Architect, do hereby declare the nature of this invention to be as
follows
This invention relates to a process for producing mono-carbonate of lime by first
forming sub-carbonate of calcium and then submitting it to the action of carbonic
acid for the purpose of forming a hard stone-like substance suitable for covering walls,
making imitation marble, and other like purposes.
In carrying out my invention, I take oxide of calcium and carbonate of calcium in
a finely pulverized condition and thoroughly mix them and add water thereto
whereupon the mixture becomes a solid homogeneous mass without revealing the
presence of hydroxide of calcium and carbonate of calcium produced by the action of
the water and, as is usual with the formation of a homogeneous substance having an
uniform grain, a double combination is formed of hydroxide of calcium and carbonate
of calcium which is expressed approximately by
and which must be regarded as the secondary effect produced by the oxide of calcium
in the presence of carbonate of calcium while the water is binding them together.
Although heat is necessarily produced by the binding action of the water and is
used for forming the double combination, no steam is produced and consequently
none of the water containing the sub-carbonate of calcium is liberated.
I then subinit the sub-carbonate of calcium to the action of carbonic acid or of air
containing carbonic acid the result of which is that the water is slowly liberated and
replaced by the carbonic acid thereby forming a hard homogeneous stone-like substance
which can be polished; painted or otherwise treated, the said substance being composed
entirely of carbonate of calcium in which it is practically impossible to detect the
simallest particles of tlie elementary ingredients.
The proportions of the ingredients which I have found to answer well for carrying
out iny process are as follows: vizt. about 45 parts by weight of carbonate of calcium
to 6 parts of oxide of calcium and sufficient water to form the mixture into a paste,
Deted is dil day of Match isso
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
A Process for Producing Mono-carbonate of Calcium.
1, FRANZ MÜHLENBRUCH, of 50, Kaiserstrasse, Magdeburg, in the Empire of
Gerinany; Architect, do hereby declare the nature of this invention and in what
imanner the same is to be performed to be particularly described and ascertained in
and by the following statement :—
This invention relates to a process for producing mono-carbonate of lime by first
forming sub-carbonate of calcium and then submitting it to the action of carbonic

page_text: acid for the purpose of forming a hard stone-like substance suitable for covering walls
making imitation marble and other like purposes.
In carrying out my invention I take oxide of calcium and carbonate of calcium in
a finely pulverized condition and thoroughly mix them and add water thereto
whereupon the mixture becomes a solid homogeneous mass without revealing the
presence of hydroxide of calcium and carbonate of calcium produced by the action of
the water and, as is usual with the formation of a homogeneous substance having an
uniform grain, a double combination is formed of hydroxide of calcium and carbonate
of calcium which is expressed approximately by
and which must be regarded as the secondary effect produced by the oxide of calcium
in the presence of carbonate of calcium while the water is binding them together.
Although heat is necessarily produced by the binding action of the water and is
used for forming the double combination no steam is produced and consequently none
of the water containing the sub-carbonate of calcium is liberated.
I then submit the sub-carbonate of calcium to the action of carbonic acid or of air
containing carbonic acid, the result of which is, that the water is slowly liberated and
replaced by the carbonic acid thereby forming a hard homogeneous stone-like
substance which can be polished, painted or otherwise treated, the said substance being
composed entirely of carbonate of calcium in which it is practically impossible to
detect the smallest particles of the elementary ingredients which certainly would not
be the case if the particles of hydrate of calcium had been simply deposited side by
side with the particles of carbonate of calcium and the former particles, simply by
absorbing carbonic acid, had been transformed into carbonate of calcium. In the
laiter case the cohesion between the last formed particles of carbonate of calcium and
those produced in the first instance would be very slight, which really is the case
when ready-made powder of hydrate of lime and powdered carbonate of calcium are,
after having been mixed, stirred up into a paste and dried and brought under the
influence of carbonic acid. In this case a water-containing sub-carbonate of calcium
would not be formed as this would only be the case when water is used to act on oxide
of calcium in the presence of carbonate of calcium.
This manner of producing carbonate of calcium is of great commercial value as it
can be used for producing artificial limestone, marble, wall-coverings, etc. Moreover,
the final product being really only carbonate of calcium, colours can easily be found
which can be added to the mixture of oxide and carbonate of calcium, or which could
be used for painting or decorating the substance without risk of being deleteriously
affected by the air or by the substance itself (which always remains the same).
Otherwise suitable covering materials can be employed to protect the colours against
the action of the air.
The substance can also be encaustic-painted afterwards, the wax being absorbed by
heat with the colours and decomposed through the alkaline reagent whereby the
mono-carbonate of calcium formed is caused to cover the particles of the colours and
thus create a durable colour decoration.
The process
can be practically carried out in the following manner :-
Finely ground or powdered carbonate of calcium (unburned lime) is mixed with a
sufficient quantity of finely ground oxide of calcium (burned lime) to form sub-
carbonate of calcium (or a larger quantity can be used). The mixture is then stirred
up with water, the effect of which through the reaction of the water on the oxide of
calcium in the presence of the carbonate of calcium, is that the mixture combines in
a solid uniform mass which consists of a hydrate compound of sub-carbonate of
calcium.

page_text: Practically 45 parts in weight of carbonate of calcium would be used with 6 parts
of oxide of calcium, which is then exposed to the influence of carbonic acid or gas
containing carbonic acid or the atmospheric air which always contains carbonic acid
whereby a solid and entirely homogeneous mono-carbonate of calcium is produced.
To the above mixture may be added sundry other materials such for example as marble
chips or sand etc., so that these additional materials, after the complete transformation
of the oxide and carbonate of calcium hydrate into carbonate of calcium, are simply
enclosed in a solid casing of carbonate of calcium, as the substance finally produced
is always mono-carbonate of calcium in which are embedded a smaller or larger
quantity of foreign substances. Such mixtures can also serve as wall-compo, wall-
covering or mortar, or be formed into artificial stone blocks or the like.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The herein described process of producing mono-carbonate of calcium consisting
essentially in mixing oxide of calcium with dry carbonate of calcium both in a finely
pulverized condition and then adding water thereto, thereby producing a hydrated
sub-calcium-carbonate (Ca, (OH)2 0, CO) which is then submitted to the action of
carbonic acid.
2. The combination with the ingredients referred to in claim 1 of substances of any
nature either before or after the addition of water, substantially as hereinbefore
described.
1000
10 th day of December
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.