Improvements in and connected with the Utilisation of Waste Sand from Glass Works.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in and connected with the Utilisation of Waste Sand
from Glass Works.
I, DOUGLAS HERMAN, of Eccleston Park, Prescot, in the County of Lancaster,
Chemist, do hereby declare the nature of this invention to be as follows:-
The quartz sand which is commonly employed for grinding plate glass and for
analogous uses is more or less ferruginous, and in the act of grinding there
becomes mixed with it finely divided metallic iron derived from the runners and
a considerable proportion of the glass which is operated on. The presence of the
metallic iron and of the oxide of iron renders the sand unsuitable for use in the
manufacture of glass of the superior varieties and, because there exists no other
local use for it, it has to be disposed of as a waste material. Since this disposal
involves not only the loss of the original materials but also considerable cost and
inconvenience, and since it consists chiefly of material which, if freed from the
iron and iron oxide, could be used on the spot, many attempts have been made
but hitherto without commerical success, to remove the obnoxious matters from
the sand. The principal difficulties in the way of any purely chemical process
are, the enormous quantities of material to be treated for the removal of a com-
paratively insignificant amount of iron and its oxide, and the fact that the oxide
exists in a diffused state throughout the mass of individual grains and not merely
on their surfaces.
According to my present invention I purify the sand by simple means so that
it may be safely used in the manufacture of plate and other superior varieties
of glass, as well as for other purposes, by grading the sand and by acting upon
the finer grades or the finest grade by a solvent of the iron and iron oxide con-
tained therein. I have found that even after the sand has been for a long time
exposed to the atmosphere, much of the metallic iron originally contained in it
remains in the metallic or magnetic state, and I take advantage of this fact to
separate the magnetic material by means of magnetic separators.
In carrying out my invention I may, by way of example, proceed as follows.
If the sand to be treated is taken directly from the grinding benches,. I pass
it
with its accompanying water, in contact with the magnetic separators by which
the magnetic matters are removed. If it be derived from the waste heaps in
a lumpy condition, it may be broken up, mixed with water, and be treated in
the same way. Or, if the sand be already in the dry pulverulent condition, it
may be treated in that condition by the separator. The separation of the
magnetic matters if adopted, may however be reserved until the completion of
the grading operation hereinafter described, and be applied only to the finer
grades of sand which are not returned to the grinding benches.
The sand, whether previously operated on by the magnetic separator o: not,
is graded in the usual manner by being mixed with water and run through
settling pits in the first of which the coarsest grains are deposited, the finest
grains being carried over to the last pit. The coarser grains may be returned

page_text: to the grinding benches for re-use and the finest grades or the finer grades are
reserved for subsequent treatment which may or may not commence with the
magnetic separation. Before the further. treatment, by a solvent, it is advan-
tageous to dry the sand for the purpose of preventing the dilution of the solvent.
This drying may be effected in various ways as for example by means of a hydro-
extractor. In drying the finest grains in the hydro-extractor, it is advan-
tageous either to provide means for drawing off water from the bottom of the
extractor or for expelling water over the top edge, since the sand forms a very
impervious wall,
Alternatively or in addition, I may dry the sand in a revolver" furnace
arranged in a sloping direction, fired at the lower end and supplied with the sand
at the upper end. The dried sand escapes or is withdrawn at the lower end.
The graded fine sand is placed in suitable vessels in which, with or without
the aid of heat, it may be treated with a suitable solvent such as hydrochloric
acid. I have found that I can recover the greater part of the acid with the iron
dissolved therein by a very simple process. Thus, the whole of the sand having
been completely wetted by the acid, and there being no superfluous acid, water
is allowed to run on the sand. A bottom outlet is provided for the escape of
the liquid and it will be found that the water gradually displaces the acid
through this outlet without mixing with it. As soon as the water reaches the
outlet, either the outlet is temporarily closed, or the issuing stream is diverted
so as not to mix with the acid." A sufficiency of water may then be allowed to
flow through the sand to remove the residual acid.
The acid which is recovered and which contains iron chlorides in solution, may
be re-used as many times as it may be effectively employed, and may thereafter
be utilised by known means for other purposes.
The purified sand is of greater value for the manufacture of glass than the
normal sand now used, because it contains a very considerable proportion of glass
mixed with it. In fact, by my process the very large proportion of the glass
now wasted in the grinding is recovered, since this glass is necessarily in a very
fine state of division and is all graded with the finest sand. The product, if
calcined, is a very fine snow-white powder having a high abrasive value, and it
is therefore also adapted for use as a polishing material.
If the sand to be acted on is of the very finest grade, some difficulty may be
experienced in getting the solvent and wash water to pass through it in reason-
able time. In this case, the sand and liquid may be agitated and be thereafter
separated by subsidence and decantation. Or it may be separated by a hydro-
extractor. Alternatively, a sufficient quantity of coarse sand may be mixed with
the fine sand to make it permeable to the liquid and the coarse sand may after-
wards be separated by sifting or by gravity in settling pits as is well understood.
If the product is to be utilised for glass manufacture, the added coarse sand may
be the sand actually used in the composition of glass, and in this case it will
not be necessary to separate the coarse addition.
1011
L
A TY 1900
Improvements in and connected with the Utilisation of Waste Sand
from Glass Works.
I, DOUGLAS HERMAN, of Eccleston Park, Prescot, in the County of Lancaster,
Chemist, do hereby declare the nature of this invention, and in what manner

page_text: the same is to be performed, to be particularly described and ascertained in and
by the following statement:―
The quartz sand which is commonly employed for grinding plate glass and for
analogous uses, is more or less ferruginous, and in the act of grinding, there be-
comes mixed with it finely divided metallic iron derived from the runners as well
as a considerable proportion of the glass which is operated on.
The presence
of the metallic iron and of the oxide of iron renders the sand unsuitable for use
in the manufacture of glass of the superior varieties and, because there exists no
other local use for it, it has to be disposed of as a waste material. Since this
disposal of it involves not only the loss of the original materials but also con-
siderable cost and inconvenience, and since the waste consists chiefly of material
which, if freed from the iron and iron oxide, could be used on the spot, many
attempts have been made, but hitherto without success, to remove the obnoxious
matters from the sand. The principal difficulties in the way of any purely
chemical process are, the enormous quantities of waste material to be treated
for the removal of a comparatively insignificant amount of iron and its oxide,
and the fact that the oxide exists in a diffused state throughout the mass of
individual grains and not merely upon their surfaces.
According to my present invention, I purify the sand by simple means and
so that it may safely be used in the manufacture of plate and other superior
varieties of glass, as well as for other purposes, by grading the waste sand and
by acting upon the finer grades by a solvent of the iron and iron oxides contained
therein. I have found that even after the waste sand has for a long time been
exposed to the atmosphere, much of the metallic iron originally contained in it,
remains in the metallic or magnetic state, and I take advantage of this fact to
separate the magnetic material by means of magnetic separators.
In carrying out my invention I may, by way of example, proceed as follows:-
If the waste sand to be treated is taken directly from the grinding benches, I
pass it with its accompanying water, in contact with the magnetic separator,
by which the magnetic matters are removed. If it be derived from the waste
heaps, in a lumpy condition, it may be broken up, mixed with water and
treated in the same way. Or, if the sand be in the dry pulverulent condition,
it may be treated in that condition by the magnetic separator. The separation
of the magnetic matters, if adopted. may however be reserved until the com-
pletion of the grading operation hereinafter described, and be applied only to the
finer grades of sand which are not returned to the grinding benches.
The sand, whether previously operated on by the magnetic separator or not,
is graded in the usual manner by being mixed with water and run through
settling pits in the first of which the coarsest grains are deposited, the finest
grains being carried over to the last pit. The coarser grains may be returned
to the grinding benches for re-use and the finest grade or the finer grades are
reserved for subsequent treatment which may or may not commence with the
magnetic separation. Before the further treatment by a solvent, it is advan-
tageous to dry the sand for the purpose of preventing the dilution of the solvent.
This drying may be effected in various ways as for example by means of a hydro-
extractor. In drying the finest grains in the hydroextractor, it is advantageous
either to provide means for drawing off water from the bottom of the extractor
or for expelling water over the top edge, since the sand forms a very impervious
wall. Alternatively, or in addition, I may dry the sand in a revolver furnace
arranged in a sloping direction, fired at the lower end and supplied with the sand
at the upper end. The dried sand escapes or it is withdrawn at the lower end.
The graded fine sand is placed in suitable vessels in which, with or without the
aid of heat, it may be treated with a suitable solvent such as hydrochloric acid.
I have found that I can recover the greater part of the acid with the iron dis-
solved therein by a very simple process. Thus, the whole of the sand having
been completely wetted by the acid, and there being no superfluous acid, water is

page_text: allowed to run on the sand. A bottom outlet is provided for the escape of the
liquid from the vessel in which the sand is treated, and it will be found that the
water gradually displaces the acid through this outlet without mixing with it.
Asisoon as the water reaches the outlet either the outlet is temporarily closed.or
the issuing stream is diverted so as not to mix with the acid. A sufficiency of
water may then be allowed to flow through the sand to remove any residual acid.
The acid which is recovered and.which contains iron chlorides in solution, may
be re-used as many times as it may be effectively employed, rand: inaya there
after be utilised by known means for other purposes.
The sand purified as hereinbefore described is of greater, value for the manu-
facture of glass than the normal sand.now used, because it contains a very con-
siderable quantity of the best glass mixed with it. In fact, by my process the
very large quantity of glass now wasted in the grinding process is recovered and
added to new glass in the process of manufacture. If the purified product in-
stead of being used in the manufacture of glass, be calcined it is found to be a
very fine snow-white powder having a high abrasive value, and it is therefore
also adapted for use as a polishing material.
If the sand to be acted on should be of the very finest grade; some difficulty
may be experienced in getting the solvent and wash water to pass through it in
reasonable time. In this case, the sand and liquid may be agitated together and
be thereafter separated by subsidence and decantation or by a hydroextractor.
Alternatively, a sufficient quantity of coarse sand may be mixed with the fine
sand to make it permeable to the liquid, and the coarse sand may afterwards.be
separated by sifting or by gravity in settling pits, as is well understood. If the
product is to be utilised in glass manufacture, the added coarse sand may be the
sand to be used in the composition of glass, and in this case it will not be
necessary to separate the coarse addition."
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is:-
1. The herein before described production or manufacture of a purified material
from the waste sand of glass works, suitable for use in the manufacture of glass,
as an abrasive agent, and for other analogous purposes, substantially as set forth.
2. In the production or manufacture of a purified material from the waste
sand of glass works, grading the sand so as to separate the finer particles, and
treating the finer grade or grades with a solvent for iron and iron oxide, substan-
tially as herein before described.
3. In the production or manufacture of a purified material from the waste
sand of glass works, grading the sand so as to separate the finer particles, treating
the finer grade or grades with a solvent for iron and iron oxide, and treating the
sand at a convenient stage with a magnetic separator for the removal of magnetic
matters, substantially as set forth.
4. In the production or manufacture of a purified material from the waste sand
of glass works, grading the sand for the separation of the finer particles, treating
these particles in the mass with a sufficiency of a solvent for iron and iron
oxide to wet the mass, and then opening an outlet at the bottom and allowing
water to flow over and through the wetted material, substantially as described.
Datel this 11th day of December A D 1899.