IMPROVE. MENTS IN THE MANUFACTURE FROM BLAST FURNACE SLAG OF BLOCKS SUITABLE FOR BUILDING PURPOSES
Year: 1871

page_text: LETTERS PATENT to Carl Friedrich Claus, of Middlesbrough-on-Tees,
in the County of York, Chemist, for the Invention of "IMPROVE.
MENTS IN THE MANUFACTURE FROM BLAST FURNACE SLAG OF BLOCKS SUITABLE
FOR BUILDING PURPOSES."
Sealed the 26th April 1872, and dated the 30th October 1871.
PROVISIONAL SPECIFICATION left by the said Carl Friedrich Claus
at the Office of the Commissioners of Patents, with his Petition, on
the 30th October 1871.
I, CARL FRIEDRICH CLAUS, of Middlesbrough-on-Tees, in the County
of York, Chemist, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE MANUFACTURE FROM BLAST FURNACE SLAG OF BLOCKS
SUITABLE FOR BUILDING PURPOSES," to be as follows:-
The object of this Invention is to manufacture blast furnace slag into
a very light honeycombed or cellular mass, from which blocks of a
cellular structure, but possessing sufficient strength for building pur-
poses, can be cut, or sawn, or moulded.

page_text: In order to produce this peculiar structure it is preferred to use
siliceous slag, such as is not of a calcareous nature, or where the furnaces
do not yield such siliceous slag, any suitable and known siliceous
substance may be added in a powdered state to the slag as it runs from
the furnace or may be mixed therewith in tanks constructed of non-
conducting material, or in large reverberatory furnaces.
In order to produce the gases by the escape of which into the
congealing slag the cellular structure thereof is produced, the slag is
either run into damp moulds formed of a non-conducting material, and
from which steam will necessarily be envolved, or air or steam is blown
by any suitable known means into the molten mass of slag, or steam,
carbonic acid, or carbonic oxide is or are caused to be evolved in the
hot and liquid slag by mixing therewith substances such as are well
known capable of producing the same, such as sand or clay containing
carbonate of lime or ferruginous sand, small coal, wood, sawdust, or
valueless iron ore. The moulds are either covered with an imperfect
conductor of heat, in order to produce as thin a crust of homogeneous
slag as possible, or the moulds are constructed of compressed infusorial
silica or lime, or any light or porous substance or substances, such as
are well known adapted for the purpose.
The cellular slag which is formed in accordance with this Invention
does not require annealing, as the numerous air cells thercin act as
non-conductors of heat, and retard the cooling effects of the air, and the
masses formed may when cold be easily cut or sawn into any desired
form or shape.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Carl Friedrich Claus in the Great Scal Patent
Office on the 30th April 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CARL
FRIEDRICH CLAUS, of Middlesbrough-on-Tees, in the County of York, 3
Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirtieth day of October, in the year.
of our Lord One thousand eight hundred and seventy-one, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors, give 3

page_text: and grant unto me, the said Carl Friedrich Claus, Her special licence,
that I, the said Carl Friedrich Claus, my executors, administrators, and
assigns, or such others as I, the said Carl Friedrich Claus, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
THE MANUFACTURE FROM BLAST FURNACE SLAG OF BLOCKS SUITABLE FOR BUILDING
PURPOSES," upon the condition (amongst others) that I, the said Carl
Friedrich Claus, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention, and
in what manner the same was to be performed, and cause the same to
be filed in the Great Seal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Carl Friedrich Claus, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement, that is to say :-
The object of my said Invention is to manufacture blast furnace
slag into a very light honeycombed or cellular mass, from which blocks
of a cellular structure, but possessing sufficient strength for building
purposes, can be cut, or sawn, or moulded.
In order to produce this peculiar structure it is preferred to use
siliceous slag, although a slag of a calcareous nature may be also
employed. Where the furnaces from which the material is derived do
not yield such siliceous slag any suitable siliceous material, such as will
be well known, may be added in a powdered state to the slag as it runs
from the furnace, or may be mixed therewith in tanks constructed of
non-conducting material, or in large reverberatory furnaces, which may
be revolving or stationary. The cellular structure before referred to is
produced by the expansion of the gases held in the slag, or resulting
from substances introduced into the same; and in order to produce or
evolve such gases, by the escape of which into the congealing slag the
cellular structure thereof is produced, the slag is either run into damp
moulds formed of a non-conducting material, and from which steam will
necessarily be evolved, or air or steam is blown by any suitable and

page_text: known means into the molten mass of slag; or steam, carbonic acid, or
carbonic oxide is or are caused to be evolved in the slag whilst the latter
is in a hot and liquid state, by mixing therewith substances, such as are
well known, capable of producing the same. As instances of such
substances, sand or clay containing carbonate of lime, or ferruginous
sand, and small coal, wood, sawdust, or valueless iron ore may be men-
tioned. Even water or slaked lime, or highly spongy or hairy or woolly
slag previously produced and stirred into the slag will ensure the desired
effect. The admixture of these gas producing substances is effected in
the tanks, pools, or revolving or stationary reverberatory furnaces named
above. The moulds are either coated with an imperfect conductor of
heat in order to produce as thin a crust of homogeneous slag as possible,
or the moulds are constructed of infusorial silica, or lime, or any light
or porous substance or substances, such as are well known, adapted for
the purpose.
The cellular slag which is formed in accordance with my said Invention
does not require annealing, as the numerous air cells therein act as non-
conductors of heat and retard the cooling effects of the air, and the
masses formed may (if not already moulded into blocks of the proper
size), when cold be casily cut or sawn into any desired form or shape.
Having thus declared and ascertained the nature of my said Invention,
and in what manner the same is to be performed, I would observe in
conclusion that what I consider novel and original, and therefore claim
as constituting the Invention secured to me by the said herein-before
in part recited Letters Patent is, the manufacture from blast furnace
slag of blocks as and for the purposes herein-before substantially set
forth and described, or any mere modifications thereof.
In witness whereof, I, the said Carl Friedrich Claus, have hercunto
set my hand and seal, this Thirtieth day of April, in the year of
our Lord One thousand eight hundred and seventy-two.