Improvements in the Preparation of Sand and like substances to be used in Making Moulds and Cores for Casting.
Year: 1898

page_text: Date of Application, 1st July, 1898
Complete Specification Left, 1st Apr., 1899-Accepted, 27th May, 1899
Improvements in the Preparation of Sand and like substances to be
used in Making Moulds and Cores for Casting.
We, JOHN HARGREAVES, of Widnes, in the County of Lancaster, Chemist, and
ANDREW POULSON, of 63, Frederick Street, Widnes, in the County of Lancaster,
Foreman Moulder, do hereby declare the nature of this invention to be as
follows:
This invention relates to the preparation of sand or the like, to be used for
forming moulds or cores for casting metals, by mixing with such sand, certain
substances to impart cohesiveness thereto and to ensure a smooth and finished
surface on the casting.
For these purposes, to impart cohesiveness, we cause to be formed in the
interstices in a mass of sand, or other like substances, to be employed for making
moulds or cores for casting metals, a mixture of water and hydrates of silica or
alumina in a gelatinous condition and a carbonate of soda or potass, by separately
or conjointly adding to and incorporating with the said sand or other like sub-
stances, water, sesqui, or bicarbonate of soda or potass and silicate or aluminate of
soda or potass in suitable manner, conditions and proportions.
The said sesqui or bicarbonate of soda or potass and silicate or aluminate of
soda or potass, may be mixed with the sand in the form of powder and the necessary
water added, or the sesqui or bicarbonate of soda or potass and silicate or aluminate
of soda or potass may be added to the sand or other like substances in form of
emulsions, or, and preferably in form of solutions, preferably in proportions of
about that indicated by their chemical equivalents to produce the desired reactions.
The said materials are intimately mixed with the sand and with each other in any
convenient manner such as by means of a disintegrator, edge runners, grinding, or
by otherwise suitably incorporating the mixed materials.
During, or subsequent to the incorporation of said added materials and sand such
materials assume a gelatinous condition in the interstices of the mass of sand, and
bind the particles of sand together. It is advantageous that a large proportion,
or and preferably, that the whole of the water necessary to moisten the sand to the
desired consistency for moulding, be homogeneously diffused in, or form part of, the
gelatinous mixture.
If desired, to ensure a smooth and finished surface on the casting, we add
carbonaceous materials to the sand and when coal is added to the sand, it is necessary
that it should be ground to a fine powder. We find that castings having a very
smooth and finished surface are obtained by incorporating with the sand, in the
form of powder, suitable fusible bituminous material such as ashphalt, coal tar
pitch, or the like, which should be friable so that it may admit of being finely
ground. The said carbonaceous, or bituminous materials may be added before,
during, or after incorporating the said materials to form the gelatinous mixture
with the sand or after such gelatinous mixture is formed; such bituminous
materials in some cases assume the form of graphite during casting and an

page_text: unusually smooth and finished surface is formed on the castings. We prefer that
the materials to form said gelatinous mixtures be added in such manner and
proportion that the gelatinization be not completed before the said substances be
thoroughly incorporated with the sand.
JOHN HARGREAVES.
ANDREW POULSON.
Improvements in the Preparation of Sand and like substances to be
used in Making Moulds and Cores for Casting.
We, JOHN HARGREAVES, of Widnes, in the County of Lancaster, Chemist, and
ANDREW POULSON, of 63, Frederick Street, Widnes, in the County of Lancaster,
Foreman Moulder, 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 the preparation of sand or the like, to be used for
forming moulds or cores for casting metals, by mixing with such sand certain
substances to impart cohesiveness thereto and to ensure smooth and finished
surfaces on the castings.
For these purposes to impart cohesiveness we cause to be formed in the interstices
in a mass of sand or other like substances, to be employed for making moulds or
cores for casting metals, a mixture of water and hydrate of silica or alumina in a
gelatinous condition and a carbonate of soda or potass, by separately, or, and
preferably, conjointly adding to and incorporating with the said sand or other like
substances, water, sesqui-carbonate or, and preferably bicarbonate of soda, or it
may be potass, and silicate or aluminate of soda or potass in suitable manner,
conditions and proportions such as hereinafter described.
The said sesqui carbonate or bicarbonate of soda or potass and silicate or
aluminate of soda or potass, may be mixed with the sand in the form of powder
and the necessary water added or the sesqui-carbonate or bicarbonate of soda or
potass and silicate or aluminate of soda or potass may be added to the sand or other
like substances in the form of emulsions or, and preferably, in the form of solutions.
The solutions are preferably first mixed together and then mixed with the sand
before gelatinization takes place. In all cases the materials are added to the sand
preferably in proportions of about that indicated by their chemical equivalents to
produce the desired reactions. We instance the following as a typical method of
carrying our invention into operation when using bicarbonate of soda and silicate
of soda in powders: 25 pounds of bicarbonate of soda and 40 pounds of silicate of
soda (soluble glass containing about 25% of Na,0) very finely ground, are
incorporated with about 4 tons of sand and then the necessary water is added to
dissolve the said powders and cause them to react upon each other, which effects
gelatinization, and to impart the desired amount of moisture to the sand. When
the bicarbonate of soda and silicate of soda are added to the sand in the form of
solutions for treating sand to be employed as "facing sand," the following
proportions give good results:-25 pounds of bicarbonate of soda are dissolved in
about 60 gallons of water to which is added and thoroughly mixed therewith about
7 gallons of a solution of silicate of soda of about 75° Twaddle density containing
about 9% of Na₂O. The said quantity of solutions will be sufficient to treat about
5 tons of sand.
When a relatively less degree of cohesiveness is required to be imparted to sand

page_text: such as for "back sand the said solutions are made more dilute by using a larger
proportion of water in forming the said solutions.
When potash salts are employed instead of soda salts they may be employed in
manner such as hereinbefore described for the use of silicate of soda and bicarbonate
of soda, thus 30 pounds of bicarbonate of potass are dissolved in about 60 gallons
of water to which is added 100 pounds of a solution of silicate of potass of
75° Twaddle density. This quantity of solutions will be sufficient to treat about
5 tons of sand.
We find the use of alkaline silicates to be more advantageous than that of alkaline
aluminates but when it is desired to employ aluminate of soda it may be used in
about the following relative proportions for the treatment of about 5 tons of
sand: 50 pounds of bicarbonate of soda are dissolved in about 50 gallons of water,
to which is afterwards added 14 gallons of a solution of aluminate of soda of
40° Twaddle density.
The said materials are intimately mixed with the sand and with each other in
any convenient manner such as by means of a disintegrator, edge runners or
grinding particularly when the sand treated is to be used as facing sand; but when
treating sand to be used for back sand the said dilute solutions of alkaline carbonate
and alkaline silicate or aluminate may be used instead of the water usually
employed for moistening the sand.
During or subsequent to the incorporation of the said added materials and sand
such materials assume a gelatinous condition in the interstices of the mass of sand
and bind the particles of sand together. It is advantageous that a large proportion
or, and preferably, that the whole of the water necessary to moisten the sand to
the desired consistency for moulding be homogeneously diffused in or form part
of the gelatinous mixture.
To ensure a smooth and finished surface on the casting we add carbonaceous
materials to the sand which is to be employed in facing moulds or making cores.
It is necessary that the carbonaceous materials be ground to a fine powder. We
find that castings having a soft and very smooth and finished surface are obtained
when there is incorporated with the sand in the form of powder suitable fusible
bituminous material such as asphalt, coal tar pitch, or the like which should be
friable so that it may admit of being finely ground. The said carbonaceous or
bituminous material is added to the sand preferably in about the usual proportions
in which coal dust is ordinarily employed and preferably before, but it may be
during or after, incorporating the said materials to form the gelatinous mixture
with the sand, or after such gelatinous mixture is formed. Edge runners or other
or
convenient means may be employed for incorporating the carbonaceous
bituminous materials with the sand. Such bituminous materials in some cases
assume the form of graphite during casting and an unusually smooth and finished
surface is formed on the castings. We prefer that the said solutions immediately
after being mixed together be incorporated with the sand so that the gelatinization
be not completed before the said solutions have been thoroughly incorporated with
the sand.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is :-
First. The process of preparing sand or like substances to be used in forming
moulds or cores for casting metals consisting in mixing therewith an alkaline
silicate or aluminate an alkaline carbonate and water in such manner that
gelatinization of the mixture is effected within the interstices of the mass
substantially as and for the purpose set forth.
Second. In treating sand or like substances to be used in forming moulds or
cores for casting metals, effecting within the interstices of such sand the gelatiniza-
tion of a mixture of water, an alkaline silicate or aluminate and an alkaline

page_text: carbonate which are first mixed with such sand substantially as and for the purpose
set forth.
Third. In treating sand and other substances to be used in forming moulds or
cores for casting metals, effecting within the interstices of such sand and other
substances the gelatinization of a mixture of water, an alkaline silicate or aluminate
and an alkaline carbonate which are first mixed with such sand substantially as
and for the purpose set forth.
Fourth. Incorporating with sand or like substances to be used in forming
moulds or cores for casting metals an alkaline silicate or aluminate and an alkaline
carbonate in the condition of powder or solutions, and water so that gelatinization
of such aikaline silicate or aluminate, alkaline carbonate and water is effected
within the interstices of the said sand and coliesiveness imparted thereto as set
forth.
11
L
1000
JOHN HARGREAVES,
ANDREW POULSON.