Improvements in the Manufacture or Production of Bricks or Blocks suitable for Building Purposes.
Year: 1898

page_text: Date of Application, 22nd July, 1898
Complete Specification Left, 15th Mar., 1899-Accepted, 13th May, 1899
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture or Production of Bricks or Blocks
suitable for Building Purposes.
We, GUSTAV ADOLF KIEFER, of 90, Marienstrasse, Karlsruhe, Baden, Architect,
and WILHELM THEODOR HERBST, of 2, Heinrichstrasse, Braunschweig, Managing
Director, both in the German Empire, do hereby declare the nature of this invention
to be as follows:-
-
This invention relates to an improved manufacture and production of bricks or
blocks suitable for building purposes which are weather-proof and very strong
and durable.
Attempts have heretofore been made to convert a material consisting of ordinary
gypsum and lime into a hard solid substance by the aid of sulphuric or sulphurous
acid, but without success.
The failures appear to be due to the use of sulphuric acid forming sulphate
of lime from the caustic lime so suddenly that no intimate combination of the
gypsum and lime takes place, and also to the fact that on using sulphurous acid,
the hardening of the ordinary gypsum, which is naturally of inferior binding
quality, is retarded to such an extent, and the gypsum loses so much of its binding
capacity, that a uniform and permanently resistant material suitable for building
purposes, cannot be obtained; experience has shewn that the longer the gypsum
is in water, mixed with sulphurous acid, without entering into binding connection,
the more will its binding and hardening capacity be reduced.
It is, further, a well known fact that gypsum, when placed in water for a
lengthened time, becomes "drowned" and loses its binding qualities.
The object of this invention is to remedy the aforesaid defects.
According to this invention powdered hydraulic lime is introduced into a
quantity of water and subsequently is partly converted into sulphate of lime by
adding sulphuric acid, in order to later on attain a more intimate and rapid
combination with the gypsum. There is then added and intimately mixed there-
with the filling substance which may be for example saw-dust, powdered peat,
chaff, ashes, sand, or the like. Then the gypsum prepared with a solution of borax
(and carefully burnt) is added, which at once enters into intimate combination
or admixture with the other ingredients. The product is then moulded and in
a short time it becomes as hard as stone. We may here mention that the use of the
gypsum or plaster of Paris as long known and brought into the market for building
purposes has been entirely excluded from use for manufacturing bricks or blocks,
since it would not enter into connection with the above mentioned constituents,
much less harden therewith.
Therefore, the effect of the process described is entirely different to the effect
obtained by the action of
1. A sulphite solution upon gypsum which has already been bound, and in
which case the said sulphite solution is solely used as a flux for hardening
agents

page_text: 2. A sulphurous acid, by which an intermediate formation of calcium sulphite
is to be effected in the mixture of lime and ordinary gypsum and by which
the product is to be converted under oxidation, into hardened gypsum, whilst in
this case the intimate connection and complete hardening, that is to say crystalliza-
tion of the whole mass is obtained by its being produced or built up from several
different components in several distinctly subsequent stages as described especially
by adding lastly the gypsum prepared with a solution of borax and carefully burnt.
The method of manufacturing bricks or blocks from a mixture of cement,
gypsum and sand with dilute sulphuric acid has, of course, been long known, this
mixture could, however, only be hardened to stone by applying heavy pressure
thereto. The present invention on the contrary is distinguished from this method
by the distinct order of mixing the ingredients and by using well burnt gypsum
whereby the hardening effect is obtained without the application of pressure, since
the mixed product, when moulded in moulds in form of a thickly consistent pulp,
readily hardens spontaneously without any pressure being applied, and after
having been dried in the air, forms without burning a hard and strong artificial
stone which is resonant or has the desirable ringing sound when struck.
Dated this 22nd day of July 1898.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.
Improvements in the Manufacture or Production of Bricks or Blocks
suitable for Building Purposes.
We, GUSTAV ADOLF KIEFER, of 90, Marienstrasse, Karlsruhe, in Baden, Architect,
and WILHELM THEODOR HERBST, of Heinrichstrasse 2, Braunschweig, Managing
Director, both in the German Empire, 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 relates to an improved manufacture and production of bricks or
blocks suitable for building purposes which are weather-proof and very strong
and durable.
Attempts have heretofore been made to convert a material consisting of ordinary
gypsum and lime into a hard solid substance by the aid of sulphuric or sulphurous
acid, but without success.
The failures appear to be due to the use of sulphuric acid forming sulphate
of lime from the caustic lime so suddenly that no intimate combination of the
gypsum and lime takes place, and also to the fact that on using sulphurous acid,
the hardening of the ordinary gypsum, which is naturally of inferior binding
quality, is retarded to such an extent, and the gypsum loses so much of its binding
capacity, that a uniform and permanently resistant material suitable for building
purposes, cannot be obtained; experience has shewn that the longer the gypsum
is in water, mixed with suluhurous acid, without entering into binding connection,
the more will its binding and hardening capacity be reduced.
It is, further, a well known fact, that gypsum, when placed in water for a
lengthened time, becomes "drowned" and loses its binding qualities.
The object of this invention is to remedy the aforesaid defects.
According to this invention powdered hydraulic lime is introduced into a
quantity of water and subsequently is partly converted into sulphate of lime by
adding sulphuric acid, in order to later on attain a more intimate and rapid
combination with the gypsum. There is then added and intimately mixed there-

page_text: with the filling substance which may be for example saw-dust, powdered peat,
chaff, ashes, sand, or the like. Then the gypsum prepared with a solution of borax
(and carefully burnt) is added, which at once enters into intimate combination
or admixture with the other ingredients. The product is then moulded and in
a short time it becomes as hard as stone. We may here mention that the use of the
gypsum or plaster of Paris as long known and brought into the market for building
purposes has been entirely excluded from use for manufacturing bricks or blocks,
since it would not enter into connection with the above mentioned constituents,
much less harden therewith.
Therefore, the effect of the process described is entirely different to the effect
obtained by the action of
1. A sulphite solution upon gypsum, which has already been bound, and in
which case the said sulphite solution is solely used as a flux for hardening
agents,
2. A sulphurous acid, by which an intermediate formation of calcium sulphite
is to be effected in the mixture of lime and ordinary gypsum and by which
the product is to be converted under oxydation, into hardened gypsum, whilst in
this case the intimate connection and complete hardening, that is to say crystalliza-
tion of the whole mass is in several subsequent stages obtained by its being pro-
duced or built up from several different components as here described.
The method of manufacturing bricks or blocks from a mixture of cement,
gypsum and sand with dilute sulphuric acid has, of course, been long known, this
mixture could, however, only be hardened to stone by applying heavy pressure
thereto. The present invention on the contrary is distinguished from this method
by the distinct order of mixing the ingredients and by using well burnt gypsum
whereby the hardening effect is obtained without the application of pressure, since
the mixed product, when moulded in moulds in form of a thickly consistent pulp,
readily hardens spontaneously without any pressure being applied, and after
having been dried in the air, forms without burning a hard and strong artificial
stone which is resonant or has the desirable ringing sound when struck.
The following examples serve to illustrate the proportions in which the various
ingredients, according to our invention, may be combined but we do not limit
ourselves to the details as they may be varied without departing from the nature
of the invention:-
EXAMPLE I.
7.5 kilograms of hydraulic lime are dissolved in 50 litres of water and one-eighth
of a litre of sulphuric acid (of a strength of 66° Beaumé) is added thereto for the
purpose of converting the lime into sulphate of lime to these ingredients there is
then added about 8 kilograms of sawdust which is thoroughly mixed therewith
and finally 35 kilograms of well-burned ground gypsum is added and the whole
again mixed. The material so obtained is formed in moulds and dried in the air.
EXAMPLE II.
7.5 kilograms of hydraulic lime are dissolved on 45 litres of water, one-eighth
of a litre of sulphuric acid (of a strength of 660 Beaumé) is added thereto; 18.5
litres of ground slag are then added and well mixed therewith and the mixture is
further well mixed with 35 kilograms of well burnt and ground gypsum. The
material so obtained is formed in moulds and dried in the air.
Having now particularly described and ascertained the nature of this
invention and in what manner the same is to be performed we declare that what
we claim is:-
The manufacture of artificial bricks or blocks suitable for building purposes, by
casting in moulds and drying in the air a material prepared by suspending
powdered hydraulic lime in water, subsequently partly converting the same into
sulphate of lime by adding sulphuric acid, then adding the filling material, such as

page_text: sawdust, powdered peat, chaff, ashes, sand or the like and thoroughly mixing the
same with the sulphate of lime and finally adding well burnt gypsum which at
once enters into an intimate combination with the other ingredients, so that
the whole product, when formed in moulds, very readily and completely hardens
to form artificial stone essentially as and for the purpose described.
Dated this 15th day of March 1899.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.