Apparatus for making crystallized glass

An apparatus is presented for economically making crystallized glass products from waste ash produced from the sewage sludge dewatered by organic matters, which is usually regarded to be difficult to process. The melting is performed in two furnaces: the primary melting furnace and the secondary melting furnace. The primary furnace melts waste ash and the primary melt is charged into the secondary melting furnace. The glassy material produced in the secondary melting furnace is charged into a crystallization furnace to convert the glassy material to a crystallized glass product. This basic configuration of the apparatus allows the production of either irregular shaped crystallized products, such as crushed stone like products, or crystallized manufactured products, such as tiles and blocks, depending on the combination of processing equipment and their operating conditions. The apparatus enables the production of crystallized glass products from waste ash feed economically, because of the flexibility and versatility in the design of the apparatus.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates in general to a method for making 
crystallized glasses, and relates in particular to a method for making 
crystallized glass products from waste ashes produced from incinerating 
sludges and industrial and public wastes. 
2. Technical Background 
with increasing concern for preservation of environment, there is an 
increasing recognition for the importance of reducing and recycling waste 
materials. Effective utilization of sludges produced from sewage and 
industrial water treatment facilities is also an important aspect of 
reducing the need for landfill and preserving the natural environment. 
The present invention relates to an apparatus for producing products 
similar to such materials as pebbles, stones, and crushed stones, and to 
an apparatus for producing such manufactured products as tiles and blocks, 
using the method for producing crystallized glasses which has been 
disclosed earlier in a Japanese Patent Application, First Publication, 
H2-413772. 
There are conventional furnaces for melting waste ash materials produced 
from incinerating sewage sludge and other types of wastes, such as rotary 
furnaces, coke beds (or vertical shaft furnaces), surface melting 
furnaces, arc furnaces, plasma furnaces and microwave melting furnaces. 
However, the slags produced from these conventional melting furnaces are 
glassy types which are only useful as low grade construction materials 
such as road fill. There has been proposals to slowly cool or treat the 
melted materials to produce crystallized aggregates. The crystallized 
aggregates made by such methods (Japanese Patent Application, First 
Publication, S56-54248, Japanese Patent Application, First Publication 
S56-54247) are used as concrete admixtures. 
The crystallized glass products made by the method of the present invention 
are far superior to those made by the conventional methods mentioned 
above, and the details of this method has already been disclosed in a 
Japanese Patent Application, First Publication H2-413772. 
The building materials using crystallized glass are made by two approaches: 
one approach is to melt a feed material of an appropriately adjusted 
composition in a conventional glass furnace and after making formed glass, 
heat treating and crystallizing steps are performed on the formed glass; 
the other approach is to prepare particulate shaped glass first from a 
melt, and shaped glass is made by heat treating and crystallizing step is 
performed on the shaped glass. However, there has been no proposal for an 
apparatus using waste materials for feed and making crystallized glass 
products tailored to the end applications. 
Applications of crystallized glass products for construction and building 
purposes are broadly divided into two categories: one is a group of 
irregular shaped products such as pebbles and crushed stones; and the 
other is a group of shaped products such as tiles and blocks. The 
irregular shaped products can be used in their original condition or used 
as raw material for secondary products as in the case of foundation stones 
or aggregates for terrazzo tiles. In either case, the end applications 
must be compatible with the characteristics of the crystallized glass, and 
used in applications having relatively high added value. For formed glass 
product applications, tiles and blocks can be used in interior 
applications such as decorative blocks and boundary stones, which are 
high-value-added products but correspondingly, the quality demands are 
also high. Therefore, it becomes important that an apparatus for making 
crystallized glass be constructed in line with the economic requirements, 
such as capital and operating costs, of the end products. 
In considering the equipment for making crystallized glasses and products, 
the essential components are melting furnace, shaping apparatus and 
crystallization furnace. 
With respect to the choice of the melting furnace, it is considered that 
the conventional glass melting furnaces are unsuitable because of the 
following three reasons. First, waste materials as feed to the melting 
furnace are quite variable in size and quality, they can vary from waste 
containing organic substances to nearly inorganic small sized particles of 
several tens of micrometers such as fly ashes from incinerators. Second, 
the ash compositions produced from the waste materials are 
multi-component, and the melt is highly corrosive to the refractories of 
the melting furnace. Third, it is necessary to satisfy production 
conditions for producing iron sulfide as a nucleating agent from iron 
oxide and sulfur compounds. 
With respect to making irregular shaped crystallized glass products in the 
shapes of sand, particles, crushed stones and small lumps, manufacturing 
cost must be low because they have low added values, and it is necessary 
to shorten the processing time. Especially for the crystallization step, 
roller hearth kilns or tunnel kilns used as crystallization furnace for 
formed blocks, bricks and tiles are unsuitable because of their long 
processing times, and the large size of the equipment. They are also heavy 
consumers of fuel, thus increasing the operating cost. 
Other problems with making the crystallized glass products are associated 
with the properties of the melt made from waste ash materials. Ordinary 
glasses exhibit good forming and malleability even at temperatures as low 
as 700.degree. to 800.degree. C., but the melt has a tendency to harden 
below about 900.degree. C. If there is a large temperature difference 
existing between the surface and the interior when making crystallized 
glass products, cracking may appear during the glass formation stage, or 
if large internal stresses are left in the glass, it may lead to cracking 
during the crystallization step. Therefore, it is necessary to control the 
cooling rate during the glass formation stage, and the conventional glass 
forming methods such as roll-drawing cannot be applied, because of the 
lack of thermal shock resistance of the formed glass and the difficulty of 
temperature control. Further, the method of melting and adhering small 
glass particles during the crystallization step is difficult to be used 
because the recycled glass is difficult to be softened before the 
crystallization temperature is reached. 
SUMMARY OF THE INVENTION 
The apparatus of the present invention resolves the problems in the 
existing apparatus for making crystallized glass products, and an 
objective is to present an apparatus which enables to produce various 
crystallized glass products, that is irregular shaped products such as 
crushed stone like products and shaped, i.e. formed, products such as 
tiles and blocks, at the costs commensurate with their respective added 
values. 
This objective is achieved in an apparatus for making a crystallized glass 
product by melting a waste ash material containing organic matters, 
producing a glassy material and subjecting the glassy material to a 
crystallization step to produce the crystallized glass product, the 
apparatus comprising: a hopper for storing the waste ash material; a 
hopper for storing a feed composition adjuster; a mixer for mixing 
materials supplied by the hoppers to make a mixed feed material; a 
constant rate feeder for supplying the mixed feed material for melting; a 
primary melting furnace of a circular type for producing a primary melt; a 
secondary melting furnace operatively connected to the primary melting 
furnace for homogenizing, defoaming and forming nuclei in the primary 
melt; a cooling and shaping apparatus disposed at the melt discharge end 
of the secondary melting furnace for producing a glassy material; and a 
crystallization furnace disposed at the discharge end of the cooling and 
shaping apparatus for converting the glassy material to the crystallized 
glass product. 
According to the apparatus for making crystallized glass products of the 
construction described above, the apparatus constructed so as to permit 
the melting step to be separated into two steps, that is, the primary 
melting of mixed feed material to produce the primary melt, and the 
secondary melting of the primary melt to homogenize, defoam and forming 
nuclei in the primary melt in preparation for crystallization treatment. 
The apparatus is thus able to handle a wide variety of feed materials from 
waste materials containing organic matters, to fine dust-like materials 
such as fly ash. Once the primary melt is prepared, it is then subjected 
to controlled condition of heating in the secondary melting to ensure that 
the glassy material will be converted to crystallized products as 
economically as possible. 
According to another aspect of the apparatus, the cooling and shaping 
apparatus enables to produce glassy irregular shaped particles, and the 
crystallization furnace of a rotary kiln type converts glassy irregular 
shaped particles to crystallized irregular shaped particles. Therefore, 
the versatile design of the basic apparatus enables the production of 
irregular shaped crystallized products efficiently and economically. 
According to another aspect of the apparatus, the cooling and shaping 
apparatus produces a glassy shaped material, and the crystallization 
furnace converts the glassy shaped material to a crystallized formed glass 
product. Therefore, the versatile design of the basic apparatus enables 
also the production of shaped crystallized products efficiently and 
economically. 
According to another aspect of apparatus, the composition of the waste ash 
material is optionally adjusted with CaO compounds to facilitate the 
production of the crystallized glass product. This assures that the 
composition is suitable for forming nuclei and the finally crystallized 
products will be of uniform quality. 
According to yet another aspect of the apparatus, the exterior of the 
primary melting furnace is force cooled to promote the formation of a 
self-lining made of a solidified primary melt on the interior wall of the 
primary melting furnace. This design achieves the dual purpose of not only 
protecting the lining of the primary furnace, but also of trapping the fly 
ash type mixed feed material which is generally difficult to melt 
efficiently. 
According to yet another aspect of the apparatus, the crystallization 
furnace controls the temperature of nuclei formation in five to thirty 
minutes duration and the temperature of the main crystal formation 
temperature in ten minutes to two hour duration. The apparatus is designed 
to achieve this processing so as to permit the production of irregular 
shaped products at an optimum production cost. 
According to yet another aspect of the apparatus, the cooling and shaping 
apparatus performs cooling so as to maintain the temperature difference 
between the interior and the exterior of the formed glassy material to 
within 100.degree. C., and the crystallization furnace performs 
temperature increase at a rate of 5.degree. C. per minute to crystallize 
the formed glassy material. The apparatus is designed carefully to achieve 
the required degree of temperature distribution within the furnace so that 
the final crystallized products will be free of cracks and the chances of 
fracture will be minimized. 
According to yet another aspect of the apparatus, the crystallization 
furnace is provided with a nuclei forming chamber and a main crystal 
growth chamber formed inside a rotary cylinder section; primary and 
secondary temperature adjusting devices for adjusting the temperatures of 
the flue gas from the primary melting furnace; a flue gas exit for 
removing the exhaust gas; and dams for retaining the glassy material. The 
apparatus is thus designed to maximize energy conservation and fuel 
utilization during the melting step of the process. 
According to the final aspect of the apparatus, the primary melting furnace 
recirculates the heat from the flue gas through an air pre-heater, and the 
crystallization furnace is provided with devices to lower the flue gas 
temperature before admitting the flue gas. The apparatus is thus designed 
to maximize energy conservation and fuel utilization during the 
crystallization step of the process.

PREFERRED EMBODIMENTS 
Outlines of the process of making crystallized glass products using the 
apparatus of the present invention will be presented first. 
Sludges containing organic matters such as from sewage treatment or waste 
materials, such as incinerator ash which can easily be scattered, are 
melted in a circular furnace serving as a primary melting furnace at 
temperatures between 1300.degree. to 1400.degree. C. to incinerate organic 
matters, and to melt the ash content in an oxidizing atmosphere. The 
primary melt from the primary melting furnace is received in a secondary 
melting furnace connected to the primary melting furnace and having 
heating devices such as combustion burners or plasma heaters. The primary 
melt is held at temperatures between 1400.degree. to 1500.degree. C. while 
subjecting the interior of the melt to a suitable reducing condition so as 
to homogenize the melt, to defoam the melt and to generate iron sulfide 
which acts as a nucleating agent. The outside portion of the melting 
furnace opposite to (the inner wall touched by) the melt is thermally 
insulated under forced cooling to promote the formation of a self-lining 
made of the solidified primary melt on the interior wall of the furnace. 
For making irregular shaped crystallized glass products, the quality 
demands are less than for the crystallized and formed glassy products. 
Therefore, the duration of treatment in the secondary melting furnace can 
be from fifteen minutes to one hour. The glass formation step can be 
performed in a slag cooling apparatus (for example, Japanese Utility 
Model, First Publication, H3-83691) to produce glass particulates, crushed 
stone-like particles and small agglomerates falling within a certain range 
of sizes. Crystallization is performed in a rotation furnace of a kiln 
type which can control the temperature for nuclei formation in five to 
thirty minutes duration and the temperature for main crystal formation in 
ten minutes to two hour duration. The furnace for this purpose should be a 
simplified circular type furnace which would not affect the quality of the 
glass greatly even if the glass particles to be crystallized are mixed or 
disturbed otherwise. Further economy in the processing cost is achieved by 
recirculating the flue gas from the melting furnace, and adjusting the gas 
temperature by cooling before admitting the gas to the crystallization 
furnace, thus avoiding the consumption of new energy. 
The present invention has thus enabled to have a crystallized glass making 
apparatus of simple construction as described above, and to utilize the 
crystallized glass as aggregates for such applications as terrazzo tiles 
and blocks as alternative to marbles and granite. 
In making formed crystallized glass products, it is necessary to perform 
homogenization and defoaming in the melting furnace sufficiently, 
therefore the duration of processing in the secondary furnace becomes 
longer than one hour. The operation of the cooling and shaping apparatus 
must also be carried out with particular attention to temperatures. The 
metal mold used for providing the shape must be preheated to 400.degree. 
to 600.degree. C. to ensure that the surface of the shaped product does 
not fall below 800.degree. C. After the temperature of the metal mold 
stabilizes, cooling is commenced in such a way to ensure that the 
temperature difference does not exceed 100.degree. C. between the interior 
and the exterior of the shaped product. The shaped product must reach a 
temperature below 700.degree. C. to ensure that the shaped product has as 
little cracks and stresses. To ensure that the shaped product remains 
sound at room temperature, it is necessary that the temperature difference 
of less than 100.degree. C. between the interior and exterior be 
maintained to a temperature below 200.degree. C. 
These and other requirements of the apparatus and the process will become 
apparent from the following descriptions of the examples presented with 
reference to FIGS. 1 to 5. 
FIG. 1 is a block diagram of an example of a facility for producing 
crystallized glass product in the form of crushed stones. The reference 
numeral 1 refers to a main hopper containing incineration ash A of a 
pre-analyzed composition, and an auxiliary hopper 2 for lime stone B to 
adjust the composition of the feed material. A mixer 4 is connected to the 
discharge ends of the hoppers 1, 2 through a feed conveyor 3. A constant 
rate feeder 5 of a turn-table type is connected to the discharge end of 
the mixer 4. A primary melting furnace (circular furnace) 6 is connected 
to the constant rate feeder 5. A burner 7 using heavy oil C as the fuel is 
provided on the primary melting furnace 6. The primary melting furnace 6 
is inclined from a high material end, i.e., where the burner 7 is located, 
to a low end connected to a secondary melting furnace 8. The secondary 
melting furnace 8 is horizontally disposed and is connected to the primary 
melting furnace 6, and the secondary melting furnace 8 is provided with a 
burner 9 using heavy oil as the fuel. FIG. 2 shows an alternative 
arrangement of the melting furnaces 6, 8. In this arrangement, one melting 
furnace 100 is divided into two sections, in which the fore-furnace is 
made into a rotary melting chamber 101, and the aft-furnace is made into a 
secondary melting chamber 102. In this case, the feed composition adjuster 
"a" is supplied to the circular melting chamber 101 which is heated by a 
burner 103. The secondary melting chamber 102 is provided with a plasma 
burner 104 and a burner 105, and a divider 106 is hanging from the upper 
wall. The secondary melt "b" from the secondary melting chamber flows over 
its discharge end. 
Returning to FIG. 1, a cooling and shaping apparatus 10 is disposed at the 
melt discharge end of the secondary melting furnace 8. A crystallization 
furnace 12 of a rotary kiln type is disposed at the discharge end of, the 
cooling and shaping apparatus 10 with an intervening glass transport 
device 11. 
As shown in FIG. 3, this crystallization furnace 12 has a nuclei forming 
chamber 120 and a main crystal growth chamber 121 formed inside a rotary 
cylinder section 122 which is driven by an electric motor 123. One end of 
the rotary cylinder 122 is a stationary section 124 having a flue gas 
inlet 125 for admitting the flue gas D from the primary melting furnace 6, 
and a product discharge opening 126 for discharging the crystallized 
product (crystallized glass product) E, as well as primary and secondary 
temperature adjusting devices 127, 128 for adjusting the temperatures of 
the flue gas D by supplying air streams F, G. The opposite stationary 
section 129 of the rotary cylinder 122 is provided with a process gas exit 
130 for exhausting the process gas H as well as a glass supply device 131 
for supplying small lumps of glassy feed material I into the rotary 
furnace 12. A given amount of the glassy feed material is retained in the 
nuclei forming chamber 120 and the main crystal growth chamber 121 by the 
provision of the dams 132, 133 and 134. 
The heat from the flue gas D of the primary melting furnace 6 is supplied 
to the crystallization furnace 12 through a flue gas temperature adjuster 
13. An air preheater 14 is connected to the process gas exit 130 of the 
crystallization furnace 12. The air preheater 14 is a multi-tube heat 
exchanger, and is designed to preheat the air supplied by the combustion 
blower 15, so as to supply heated air to the primary melting furnace 6. 
The process gas from the air preheater 14 is forwarded to a gas scrubbing 
tower 16 of a spray tower type. The gas scrubbing tower 16 is provided 
with a circulation pump 17 for circulating the cooling liquid, and with a 
chimney 19 having a suction blower 18. A pressure adjustment damper 20 is 
provided at the entry end of the suction blower 18, and the interior 
pressure of the primary melting furnace 6 is kept constant by the damper 
20. The air which has passed through the flue gas temperature adjuster 13 
is discharged from the chimney 19 preventing the formation of a white 
smoke discharge. 
The process of producing crystallized glass products from waste ash using 
the apparatus of the above-described construction will be explained in the 
following. The example given below is a case of producing two tons/day of 
a crushed stone-like crystallized glass product from waste ash generated 
from dehydrated sludge cake made by using polymer coagulating agents. 
First, a pre-analyzed waste ash A (to ascertain that the composition is 
suitable for producing crystallized glass products) and the calcined 
limestone B, as the feed composition adjuster, are discharged from the 
hoppers 1, 2 in a specific quantitative amount, and are forwarded to the 
mixer 4 by way of the feed conveyor 3. After mixing the waste ash A and 
the calcined limestone B thoroughly in the mixer 4, the adjusted feed 
mixture "a" is stored in the constant rate feeder 5. A specific amount of 
the adjusted feed mixture "a" is supplied continuously by air transport to 
the primary melting furnace 6 from the turn table of the constant rate 
feeder 5. The primary melting furnace 6 has been heated to 1350.degree. C. 
by the burner 7 using heavy oil fuel C. The adjusted mixture "a" 
transported by air from the constant rate feeder 5 is blown tangentially 
into the primary melting furnace 6, and is directed against the wall of 
the furnace by a centrifugal force. The wall of the primary melting 
furnace 6 has already been coated with a covering layer of the previously 
melted and solidified primary melt of the waste ash, and the newly 
supplied waste ash "a" is trapped in the covering layer. The trapped waste 
ash "a" is melted by the actions of the heat conducted from the covering 
layer and the radiant heat. The melt flows down to the bottom of the 
primary melting furnace 6 from which it flows down into the secondary 
melting furnace 8. The secondary melting furnace 8 is kept at about 
1600.degree. C. by the heavy oil burning burner 9, and the primary melt 
supplied to the secondary melting furnace 8 is radiatively heated to 
1450.degree. C. to make a secondary melt. The secondary melt is retained 
in the secondary melting furnace 8 for not less than 15 minutes so as to 
equalize the temperature to homogenize the melt and removing gaseous 
products (defoaming) entrapped in the interior of the melt or generated by 
various reactions. The secondary melt "b" dropped from the secondary 
melting furnace 8 into the cooling and shaping apparatus 10 is made into 
small lumps I, is transported by the glass transport device 11, and is 
sent into the interior of the crystallization furnace 12 by the glass 
transport device 131 of the crystallization furnace 12, as illustrated in 
FIG. 3. The heat of the flue gas D from the primary melting furnace 6 is 
supplied to the crystallization furnace 12 after being removed of flying 
dust particles in the flue gas temperature adjuster 13, and being adjusted 
to a set temperature of the crystallization furnace 12. The small lumps I 
are heated and retained in the nuclei forming temperature range, between 
800.degree. to 900.degree. C., of the chamber 120 for not less than 15 
minutes. The small lumps I are then sent to the main crystal growth 
chamber 121 and are held in the crystal growth temperature range, between 
1000.degree. and 1100.degree. C., for not less than 15 minutes in the main 
crystal growth chamber 121. The crystallized glass product E thus formed 
is dropped from the product exit 126 and is collected. The process gas H 
from the crystallization furnace 12 is sent to the air pre-heater 14 to 
recover heat. The air heated by the pre-heater 14 is supplied to the 
primary melting furnace 6, and the process gas from the pre-heater 14 is 
sent to the gas scrubber tower 16 to clean the gas. The gas scrubber 16 is 
supplied with input water J and the scrubbing water is circulated by the 
circulating pump 17, and a part of the scrubbing water is expelled out of 
the system as discard water K. The exhaust gas cleaned in the scrubbing 
tower 16 is withdrawn by the suction blower 18 and is exhausted from the 
chimney 19. 
The results obtained from the operation of the crystallized glass making 
apparatus will be presented in the following. 
First, some examples of the compositions of the waste ashes produced from 
the sewage sludge dewatered by polymer matters are shown in Table 1. In 
this table, Y=CaO/(SiO.sub.2 +Al.sub.2 O.sub.3). 
The melting conditions for melting the adjusted ashes A, B and C are shown 
in Table 2, and the types of irregular glass samples, the heat treating 
conditions for these irregular glass samples and the evaluation results 
are shown in Table 3. 
The evaluation test in Table 3 were performed by crushing the irregular 
glass samples with a hammer, and observing the fragments with a magnifying 
glass (.times.8). The results were reported in terms of a circle for those 
samples which produced particles of less than 0.3 mm size, a triangle for 
those samples which showed crystallization but the fragments were larger 
than 0.3 mm size, and a cross for those samples having uncrystallized 
center portion. 
The properties of the crystallized glass samples 1 to 9 shown in Table 3 
are reported in Table 4 together with the test results for natural marble 
for comparison. The resistances to acid attack and alkaline attack were 
evaluated by measuring the weight loss after immersing a sample of 
15.times.15.times.10 mm size for 250 hours at 25.degree. C. in an acid 
solution (5% H.sub.2 SO.sub.4) and in an alkaline solution (5% NaOH). 
As evident from the results in Table 4, the crystallized glass samples 
prepared in the apparatus of the present invention are superior to natural 
marble in their strength and chemical properties, and that they can be 
used as aggregates without causing any problems. 
Evaluation tests were performed by making terrazzo tiles using the 
irregular shaped crystallized glass samples from Table 3 and the natural 
marble. The terrazzo tiles in this case were produced by hardening mostly 
crushed natural marble as aggregates with cement, and finished by 
polishing to make the tile resemble the color tones of natural stones. The 
aggregate mixing conditions and the evaluation results of the terrazzo 
tiles thus produced are reported in Table 5 together with JIS (Japanese 
Industrial Standards) requirements for the terrazzo tiles. 
The results shown in Table 5 confirmed that the products made by the 
crystallized glass aggregate materials of the present invention are able 
to produce secondary manufactured products having properties equal to or 
better than those of the natural marble sample. 
Next, the basic apparatus configuration of the present invention was 
applied to making tile and block shaped samples of 40 to 50 mm squares and 
10 to 100 mm thickness from dehydrated cakes of waste ashes containing 
polymer matters. 
FIG. 4 shows a block diagram of an example of the facility for producing 
crystallized shaped glass products, such as tiles and blocks. This 
facility is similar to that shown in FIG. 1 for making irregular-shaped 
crystallized glass products. The differences between the apparatus of this 
example and that for making irregular shaped products are that the 
previous cooling and shading apparatus 10, the glass transport device 11 
and the crystallization furnace are replaced by a shaping apparatus 30 and 
a crystallization furnace (not shown) which is an ordinary electric 
furnace. 
The above shaping apparatus 30, as illustrated in FIGS. 4 and 5, has a main 
body 300 and a separable lower mold 301. The spaces above and below the 
lower mold 301 are provided with a temperature adjusting device 302 for 
supplying heating gas (or cooling gas) via temperature adjusting dampers 
303, 304. The upper section of the main body 300 is provided with a 
shut-off valve 305. 
In the following, the process of making crystallized glass tiles and block 
products of 50 to 400 mm squares and 10 to 100 mm thickness from the waste 
ashes produced from the sewage sludge dewatered by polymer matters will be 
described. 
First, pre-analyzed waste ashes A and the composition adjuster (calcined 
limestone) B were-mixed thoroughly in a mixer 4 to produce a feed mixture 
of a suitable composition for producing crystallized glass, and 
continually charged into the primary melting furnace 6. The primary 
melting furnace 6 has been pre-heated to 1400.degree. C. with a burner 7 
using heavy oil C. The feed mixture "a" transported by air is charged into 
the primary furnace 6 tangentially, and is directed against the wall of 
the furnace by a centrifugal force. The wall of the primary melting 
furnace 6 has already been pre-coated with a covering layer of the 
previously melted and solidified primary melt of the waste ash, and the 
newly supplied waste ash "a" is trapped in the covering layer. The trapped 
waste ash "a" is melted by the actions of the heat conducted from the 
covering layer and the radiant heat. The primary melt runs down to the 
bottom section of the primary melting furnace 6, and drops into the 
secondary melting furnace 8. This condition is illustrated in FIG. 5. 
The secondary melting furnace 8 is maintained at about 1650.degree. C. by a 
heavy oil burning burner 9, and the primary melt supplied to the secondary 
melting furnace 8 is raised to 1500.degree. C. by the radiative heat. The 
melt is retained in the secondary melting furnace 8 for not less than one 
hour to heat the melt evenly throughout and to homogenize the melt, as 
well as removing gaseous matters produced by various reactions and 
entrappad gases. The melt "b" (the secondary melt) dropped from the 
secondary melting furnace 8 is placed in a shaping apparatus 30 to produce 
a shaped glassy material. The main body 300 of the shaping apparatus 30 is 
provided with metal molds 301 of a size equal to the size of the tiles or 
blocks to be produced. Before the melt is received in the mold 301, the 
upper and lower sections of the mold 301 are heated to provide a 
temperature range between 400.degree. to 600.degree. C. by the gas from 
the temperature adjuster 302. After receiving a certain amount of the melt 
in the mold 301, the shut-off valve 305 is closed, and the melt "b" is 
cooled so that the temperature difference between the upper and lower 
sections will be not more than 100.degree. C. by adjusting the amount of 
flow of cooling gas through the adjustments of the dampers 303, 304 to 
obtain a crystallized glass product L. The shaped glassy material L is 
removed from the shaping apparatus 30 at a removal temperature between 
200.degree. to 700.degree. C., and the placed in an electrically heated 
crystallization furnace (not shown). The glassy material L is heated at a 
rate of 5.degree. C. per minute starting from the removal temperature to 
850.degree. C., and the glassy material L is held for one hour at this 
temperature. The glassy material L is then heated again to 1050.degree. C. 
at a rate of 5.degree. C. per minute, and it is held at this temperature 
for four hours to crystallize the glassy material L. The glassy material L 
is cooled to room temperature to produce a crystallized shaped product, 
and the properties were evaluated. 
The operation of the above-presented apparatus will be described in the 
following. The waste ashes used in this example were the same as those 
shown in Table 1, and the composition adjusters A, B and C were the same 
as those shown in Table 1. The glass compositions using the composition 
adjusted ashes and their melting conditions are shown in Table 6. 
The conditions for shaping the formed glasses, the evaluation results of 
the formed glass samples and the evaluation results of the crystallized 
glass product samples are shown in Table 7. 
In Table 7, crosses are for samples showing cracks or fractures; triangles 
are for those showing no cracks or fractures but showing uncrystallized 
center upon cutting of the crystallized samples; and circles are for good 
samples. For the samples produced in the examples of the present invention 
in Table 7, X-ray diffraction analyses for confirming the presence or 
absence of precipitated anorthite crystals, compression strength tests, 
thermal expansion tests, acid resistance, alkaline resistance, water 
absorption and specific gravity were carried out in accordance with JIS 
(Japanese Industrial Standards) requirements. The results are reported in 
Table 8, together with the results of evaluation on natural granite. Tile 
evaluation tests for some of the product samples are shown in Table 9. 
As confirmed by the results shown in these Tables, the crystallized glass 
products produced in the apparatus and method of the present invention 
have the same degree of strength and chemical properties as those shown by 
natural granite sample. 
TABLE 1 
__________________________________________________________________________ 
Adjustment 
Adjustment 
Adjustment 
WASTE ASH 
A B C 
COMPOSITION 
Ash A 
After Adj 
Ash B 
After Adj 
Ash C 
After Adj 
__________________________________________________________________________ 
SiO.sub.2 
42.3 
35.0 44.1 
43.2 41.7 
35.5 
Al.sub.2 O.sub.3 
20.4 
19.8 18.6 
11.8 15.5 
18.7 
CaO 6.5 38.0 6.5 20.3 6.9 32.0 
MgO 2.2 2.5 2.1 
Fe.sub.2 O.sub.3 
9.5 5.0 7.7 10.3 8.3 6.4 
P.sub.2 O.sub.5 
6.2 9.1 13.0 
Na.sub.2 O 
0.8 0.5 0.5 
K.sub.2 O 
1.4 0.9 0.8 
Others 10.7 10.1 11.2 
C 0.3 5.0 1.2 
S 2.0 0.8 2.8 
Y 0.69 0.37 0.59 
__________________________________________________________________________ 
TABLE 2 
__________________________________________________________________________ 
Present 
Adjusting 
P. Melting 
P. Melting 
S. Melting 
S. Melting 
Examples 
Condition 
Temp. (.degree.C.) 
Time (min) 
Temp. (.degree.C.) 
Time (min) 
__________________________________________________________________________ 
1 A 1350 40 1450 15 
2 B 1400 20 1450 25 
3 A 1350 30 1500 20 
4 C 1400 25 1500 30 
5 A 1350 40 1400 35 
6 B 1400 20 1450 20 
7 C 1400 30 1450 15 
8 A 1350 35 1500 15 
9 B 1400 40 1450 25 
Over Range 
10 A 1350 30 1400 30 
11 B 1400 25 1450 10 
12 A 1350 40 1500 15 
13 C 1400 30 1400 30 
__________________________________________________________________________ 
TABLE 3 
__________________________________________________________________________ 
Ir Glass 
Ir. Glass 
P. Holding 
P. Holding 
S. Melting 
S. Melting 
Present 
Forming 
size Temperature 
Time Temperature 
Time Quality 
Examples 
Method 
(mm) (.degree.C.) 
(min) (.degree.C.) 
(min) Judgement 
__________________________________________________________________________ 
1 Water Jet 
0.5-2 
800 5 1050 15 .smallcircle. 
2 " 0.5-2 
850 10 1100 10 .smallcircle. 
3 " 2-5 900 10 1000 25 .smallcircle. 
4 " 2-5 850 15 1050 20 .smallcircle. 
5 Air Cool 
5-30 800 20 1100 30 .smallcircle. 
6 " 5-30 850 30 1050 25 .smallcircle. 
7 " 30-100 
900 15 1050 40 .smallcircle. 
8 " 30-100 
850 25 1100 110 .smallcircle. 
9 " 30-100 
800 30 1050 80 .smallcircle. 
Over Range 
10 Air Cool 
5-30 850 20 950 10 x 
11 " 30-100 
900 30 1100 30 .DELTA. 
12 Water Jet 
0.5-2 
750 3 1050 20 .DELTA. 
13 " 2-5 850 10 1000 5 .DELTA. 
__________________________________________________________________________ 
TABLE 4 
__________________________________________________________________________ 
Compressive 
Acid Alkaline 
Water 
Present 
Anorthite 
Strength 
Resistance 
Resistance 
Absorption 
Specific 
Examples 
Detected 
(Kgf/cm.sup.2) 
(%) (%) (%) Gravity 
__________________________________________________________________________ 
1 Yes 1280 0.13 0.06 0.0 3.10 
2 " 1300 0.12 0.08 0.0 3.05 
3 " 1350 0.16 0.09 0.05 3.15 
4 " 1420 0.09 0.05 0.0 3.06 
5 " 1460 0.18 0.08 0.0 3.10 
6 " 1520 0.30 0.04 0.0 3.15 
7 " 1440 0.15 0.06 0.0 3.10 
8 " 1380 0.25 0.10 0.0 3.05 
9 " 1460 0.18 0.09 0.0 3.04 
Natural 
-- 1200 8.5 0.30 0.2 2.71 
Marble 
__________________________________________________________________________ 
TABLE 5 
______________________________________ 
Test Items 
Mixing Ratio (%) 
Bending 
Crystal Strength Impact Sliding 
Glass Marble (Kgf/cm.sup.2) 
Test Test 
______________________________________ 
100 0 820 No Crack Good 
80 20 780 " " 
60 40 730 " " 
40 60 810 " " 
20 80 760 " " 
0 100 800 " " 
Reference 
JIS A 550 " " 
Standard 5415 
______________________________________ 
Wet road resistance is over 65 
TABLE 6 
__________________________________________________________________________ 
P. Melting 
P. Melting 
S. Melting 
S. Melting 
Present 
Adjusting 
Temperature 
Time Temperature 
Time 
Examples 
Condition 
(.degree.C.) 
(min) (.degree.C.) 
(Hr) 
__________________________________________________________________________ 
1 C 1450 40 1450 1.5 
2 A 1400 20 1450 2.5 
3 B 1300 30 1500 2.0 
4 C 1350 25 1500 2.0 
5 A 1400 40 1400 3.0 
6 B 1350 20 1450 2.0 
7 A 1400 30 1450 1.5 
8 C 1400 35 1500 1.5 
9 B 1350 40 1450 2.5 
Over Range 
10 A 1350 30 1400 1.5 
11 B 1400 25 1450 0.75 
12 A 1350 40 1500 1.0 
13 C 1400 30 1400 0.5 
__________________________________________________________________________ 
TABLE 7 
__________________________________________________________________________ 
Quality 
Present 
W .times. L .times. T 
Sourr Temp. 
Temp.Diff. 
Time 
Glass Temp. 
Judgement 
Examples 
(mm) (.degree.C.) 
(.degree.C.) 
(Hr) 
(.degree.C.) 
Form Glass 
Aft. Cryst 
__________________________________________________________________________ 
1 100 .times. 100 .times. 10 
450 90 3.0 
650 .smallcircle. 
.smallcircle. 
2 200 .times. 200 .times. 15 
550 85 4.0 
600 .smallcircle. 
.smallcircle. 
3 300 .times. 300 .times. 25 
600 100 2.0 
650 .smallcircle. 
.smallcircle. 
4 400 .times. 400 .times. 30 
500 50 2.5 
700 .smallcircle. 
.smallcircle. 
5 50 .times. 50 .times. 50 
450 80 3.0 
600 .smallcircle. 
.smallcircle. 
6 100 .times. 100 .times. 100 
600 95 4.0 
500 .smallcircle. 
.smallcircle. 
7 200 .times. 200 .times. 20 
550 60 2.5 
700 .smallcircle. 
.smallcircle. 
8 200 .times. 200 .times. 30 
500 85 2.5 
680 .smallcircle. 
.smallcircle. 
9 400 .times. 400 .times. 15 
600 70 3.0 
700 .smallcircle. 
.smallcircle. 
Over Range 
10 200 .times. 200 .times. 15 
350 155 2.0 
650 x -- 
11 100 .times. 100 .times. 10 
700 60 5.5 
400 .smallcircle. 
.DELTA. 
12 50 .times. 50 .times. 50 
600 120 4.0 
550 x -- 
13 300 .times. 300 .times. 20 
300 180 4.0 
300 x -- 
__________________________________________________________________________ 
TABLE 8 
__________________________________________________________________________ 
Compressive 
Thermal 
Acid Alkaline 
Water 
Present 
Anorthite 
Strength 
Expansion 
Resistance 
Resistance 
Absorption 
Specific 
Examples 
Detected 
(Kgf/cm.sup.2) 
(10.sup.-7 /.degree.C.) 
(%) (%) (%) Gravity 
__________________________________________________________________________ 
1 YES 1600 78 0.10 0.04 0.0 3.04 
2 " 1550 73 0.15 0.07 0.0 3.06 
3 " 1580 77 0.11 0.06 0.05 3.09 
4 " 1540 72 0.16 0.09 0.0 3.07 
5 " 1560 79 0.09 0.04 0.0 3.01 
6 " 1520 76 0.18 0.06 0.0 3.08 
7 " 1550 80 0.22 0.05 0.0 3.06 
8 " 1530 73 0.15 0.08 0.0 3.11 
9 " 1575 72 0.24 0.03 0.0 3.10 
Granite 1520 83 1.1 0.1 0.8 2.7 
__________________________________________________________________________ 
TABLE 9 
______________________________________ 
Test Items 
Bending Wear Test 
Present Strength Impact (loss in 
Freeze/ 
Glass (Kgf/cm.sup.2) 
Test gram) Thaw Test 
______________________________________ 
1 620 No Crack 0.010 Good* 
2 580 " 0.005 " 
4 600 " 0.006 " 
5 560 " 0.008 " 
7 560 " 0.004 " 
9 630 " 0.007 " 
Reference " &lt;0.1 " 
Standard 
______________________________________ 
*Good indicates that there was no cracking or flaking.