An Improved Process for the Production of Artificial Stone, Cement, Plaster, and the like, from Sand, Lime and other Materials.
Year: 1899

page_text: Date of Application, 14th Aug., 1899
Complete Specification Left, 9th May, 1900-Accepted, 30th June, 1900
PROVISIONAL SPECIFICATION.
An Improved Process for the Production of Artificial Stone, Cement,
Plaster, and the like, from Sand, Lime and other Materials.
I, STEFAN ZIENTARSKI, Engineer, of Wspolna Street, 47A, Warsaw, Russia, do
hereby declare the nature of this invention to be as follows:-
The fact that by the action of alum gypsum and other salts of lime the
slaking process of the lime is prolonged has long been known, but attempts to
obtain a good binding substance by the combined action of these salts have not
proved successful, it being absolutely necessary to pour in a large quantity of
water, in order that the material may not be subsequently slaked by absorbing
moisture from the air and crumble when heated (during the slaking process).
Even kinds of pulverised lime which are hard to slake when converted into hydrates
the above mentioned salts being made use of produce a mortar which heats after a
certain time, increases in volume and crumbles, if an excess of water besnot
introduced.
In using water in excess, a substance is obtained after drying that is not very
compact and does not bind the sand in the lime and sand mortar at all strongly.
The lime in such mortar acts feebly and slowly on the silicious earth;-so-called
calcareous substances must in order to ensure à good binding be subjected to the
action of steam in hermetically closed boilers at a pressure of 6 to 8 atmospheres
during 6 to 12 hours. By the present process a compact and heavy hydrate of
lime (slaked lime) is obtained without excess of water; to the water or to the
lime cheap substances containing alkalis are added, which act together in elimina-
ting the silicate from the sand (hydrate of lime being slowly and gradually
formed) the process is carried out as follows:-
To 100 parts by weight of powdered unslaked lime; 6 to 15 parts of powdered
dry unburnt clay, 5 to 25 parts of sifted ashes or ordinary ground slag and 1 to
parts of alum, gypsum or other powdered salts of lime are added.
Such a mass (but with a small addition of ashes) mixed with water to form a
thick pulp (20 to 35% of water) hardens and after a few days becomes harder
than gypsum.
In order to obtain a homogeneous mixture of lime and sand it
is necessary to mix 5 to 20 parts of the previously prepared mixture with 95 to
80 parts of sand, in a dry state, and, after mixing to add 5 to 9% of water by
weight of the whole mixture (according to the quantity of lime used). After being
mixed the mass must dry solid only showing traces of water on the surface when
struck.
An alteration of the foregoing process that, instead of powdered salts being
added to the lime they are dissolved in or mixed with the water which is employed
for slaking.
The quantity of gypsum and alum taken need not exceed 1 to 100 parts by
weight of water.
A further modification consists in adding powdered clay to the powdered un-
slaked lime; on the other hand for moistening this mass mixed with sand ash

page_text: lye is used instead of water, the suitable lime salt or alum must be dissolved in
this lye. The mass produced in this way according to one of these processes and
closely pressed or stamped together binds within a few hours, does not heat in
hardening, or increase in buik, and neither cracks nor crumbles. The mass
produced in the manner indicated can be made use of in the following way;
With a relatively weak mixture of the same roofing tiles can be made in presses
or moulds. Such articles, after being dried naturally in the air for 2 or 3 weeks
acquire a hardness equal to that of bricks made of burnt clay. If they be sub-
jected to the action of steam at a pressure of 8 atmospheres the hardening process
is effected twice as quickly as with articles produced in another way with lime and
sand. Moreover the articles preduced with the substance now in question require
no previous artificial drying and heating for introduction to the boiler, as, after
being taken from the moulds they harden (in a hydraulic sense) within a few
hours and are sufficiently dry in themselves. Such articles also harden well in
weak cold or warm lye if lime be dissolved in the same (milk of lime).
With a mixture that is richer in lime, walls for houses can be made without
any previous preparation of bricks by stamping out the mixture in wooden boxes,
which form the boundaries of the walls, as concrete walls are made, bricks, stones
and rubbish being added. Finally this mixture can be employed for cleaning
down or plastering houses, concreting floors and roofs and as a ground work for
wood, asphalt and granite paving and especially in all cases in which at present
mortar made with cement or with lime and cement is employed.
Dated this 14th day of Juouet 1890
REGINALD W. BARKER,
Applicant's Agent, 56, Ludgate Hill, London, E.C.
An Improved Process for the Production of Artificial Stone, Cement,
Plaster, and the like, from Sand, Lime and other Materials.
I, STEFAN ZIENTARSKI, Engineer, of Wspolna Street, 47A, Warsaw, Russia, 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-
This invention is based on the fact that when being slaked, lime can act on the
silicic acid contained in the sand, so that silicates of lime are produced, which
cause the combination of lime and sand to become very hard. Thus, we are readily
led so to arrange the slaking process of the lime that the slaking only takes place
when the lime is already mixed with the filling material that is, the sand, and
placed in moulds. It has been found that certain substances such as alum and
gypsum have the property of retarding or prolonging the slaking process.
Attempts have therefore been made to produce a combination of lime and sand
containing a certain percentage of added alum or gypsum, so that the mass could
be formed before the slaking process begins. This process, however, has not
produced any important results, as these additional materials, it is true, somewhat
retard the process but with a well pressed mass, the slaking process begins after
a few hours and proceeds proportionately too rapidly (heat being generated),
causing a forcing of the mass, so that the formed objects fall to pieces. In the
production of bricks made of lime and sand, when lime previously slaked has
been employed, additions have been made of substances containing silicic acid in
a readily soluble form as sand, in order to obtain silicates of lime for hardening

page_text: the bricks. As substances of this kind, the English Patent No. 22227 of 1893
for example mentions ashes, slag, coke, stone, clay and the like. As however
previously mentioned, the sand in this case as principal constituent of the mass of
lime and sand is in not way attacked, but independently of the sand silicates of
lime are formed from the other admixtures, still these silicates do not effect a
complete hardening of the prepared stone. The present process is based, as
distinguished from the foregoing, on the mixing of the unslaked lime with a
substance which absorbs water and subsequently conveys this water slowly and
gradually to the lime, so that when the lime has been slaked, no alteration in the
volume can occur. The process consists chiefly in adding to the unslaked lime
powder, say 15% of powdered un-burned clay, in addition to the usual percentages
of alum or gypsum. This mass is then stirred up with a small quantity of water
and then mixed with sand, and, if preferred with the addition of another filling
material, in the proportion of about 1 part of the mixture of lime to from 6 to
8 parts of sand.
The plastic mass is then pressed in moulds and left to stand. After the pressing,
the line is gradually slaked, without the finished object becoming heated or any
change in the volume.
The addition of alum and gypsum can if desired be effected in such a manner
that these substances are previously dissolved in water this water being then
used for stirring up the mixture of lime and clay.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, declare that what
I claim is:-
(1) An improved process for producing a material composed of lime and sand,
that hardens in the air, the distinguishing feature of which is that beyond the
usual materials employed for retarding the slaking operation, such as alum or
gypsum, pulverised unburnt clay up to 15% is added to the unslaked lime powder
whereupon the mixture is reduced with the sand to a plastic state by means of
clear water, substantially as described.
(2) A modification of the improved process described under Claim 1 for the
production of a compound of lime and sand, the distinguishing feature of which is
that the mixture made of unslaked lime powder and unburned clay is stirred up
with the sand with a suitable quantity of water in which alum or gypsum in a
previously determined quantity is dissolved substantially as described.
Dated this 9th day of May 1900.
REGINALD W. BARKER,
Applicant's Agent, 56, Ludgate Hill, London, E.C.