Apparatus and a process for heating a material

This invention is directed to a method and an apparatus to heat certain particles. These certain particles are heated to make them more desirable. In the heating of these particles, it is often desirable to expand the particles to make a light-weight aggregate. The light-weight aggregate may be used in making a building material or the like. In carrying out the process of heating these particles, there is used air for combustion of the combustible fuel and only a minimum of air for carrying of the particles or expansion of the particles.

THE GENERAL BACKGROUND OF THE INVENTION 
For, approximately, twenty-five years, certain materials, such as zeolite, 
vermiculite, perlite, and the like have been expanded into light-weight 
aggregates. Since 1946, there has been developed apparatus and methods for 
expanding these certain materials. These materials are given a heat 
treatment in the range of about 700.degree. F. to about 3000.degree. F. to 
process them into expanded solid particles. A material which may be used 
for illustrative purposes is perlite. 
Perlite is an aluminal-silicate mineral that is noncrystaline and glasslike 
in its nature. When perlite ore is ground to the approximate particle size 
of sand, it has a density of about 75 lbs. per cubic foot, although this 
density can vary somewhat. Perlite contains a small amount of sodium oxide 
and potassium oxide which acts as a flux and reduces the melting point of 
the mixture of the perlite and the oxide. Also, there is a small 
percentage of chemically combined water in the perlite. When high 
temperature is applied to a perlite particle, the surface softens and the 
water turns to steam causing the perlite particle to expand. The average 
dentsity of the expanded perlite particle is 8 lbs. per cubic foot, 
although it is possible to get the density as low as 3 or 4 lbs. per cubic 
foot. The particle size of the expanded product is controlled, to a 
degree, by the particle size of the ore. The various markets for expanded 
perlite particles are, essentially, controlled by the particle size of the 
expanded product. 
The perlite ore is mined by open pit methods, either drill and blast, or in 
some cases, dug, directly, with large bulldozers and rippers. The ore is 
then transported to a mill where the rock is crushed, ground, dried and 
screened to various particle size ranges to meet specifications for 
various markets. The finished ore is then shipped by covered hopper cans 
all over the country to expanding plants where it is heated and expanded 
into its final form and distributed from these plants. The ore presently 
used comes from five states: New Mexico, Colorado, Arizona, California, 
and Idaho. Probably, 85% of the ore is mined at No Agua, New Mexico, and 
shipped from Antonito, Colorado, the closest rail head. 
At the present time, the largest particle size of perlite ore used for 
expansion purposes is about 1/8" in diameter. The largest expanded perlite 
particle does not exceed about 3/8" in diameter. 
The perlite industry received its start toward the end of World War II. In 
the formative years of the perlite industry, three types of furnaces were 
developed for expanding the perlite ore to form expanded perlite 
particles. These three types of furnaces were the stationary horizontal 
furnace, rotary furnace, and vertical furnace. 
The vertical furnace is by far the most popular design. The rotary furnace 
is next in popularity with the stationary horizontal furnace being third 
in popularity. The vertical furnace is capable of heating and expanding 
all gradations of ore. The rotary furnace works best on coarse ore. The 
horizontal stationary furnace is used on fine ores. 
The vertical furnace comprises a vertical tube. A burner is placed at the 
bottom of the tube looking upwardly and a draft is provided by a fan 
downstream from the vertical tube. The ore is dropped directly into the 
flame about midway of the tube. The particles fall down, downwardly, and 
due to the heat in the vertical tube, the particles are heated and start 
to expand. With expansion, the density of the particles decreases, and the 
rate of fall in the vertical furnace slows. Then, when the particles have 
expanded, sufficiently, the density of the particles decreases and the 
force of gravity on the particles is overcome by the upward draft in the 
furnace and the particles reverse their direction and exit out the top of 
the vertical furnace or vertical tube. These expanded particles are 
carried, pneumatically, to a collector, such as a cyclone or bag house and 
collected. 
The rotary furnace is, essentially, a set of concentric cylinders that are 
set, horizontally, and rotate in the same manner as the rotary kiln. There 
are three cylinders, one inside the other. The ore is fed into the annular 
space between the inside cylinder and the center cylinder. The ore is 
preheated in this space. The preheated ore is then fed into the inside 
cylinder. This inside cylinder has a burner mounted in it that provides 
the heat. As the ore expands, the lighter expanded particles enter into 
the airstream passing through the furnace and are carried out of the 
furnace. The heavier particles are expanded into the expanded particles 
and put into the airstream at the end of the furnace. The expanded 
particles are collected in a fashion similar to that with a vertical 
furnace in that these particles can be collected in a cyclone or bag 
house. 
The horizontal stationary furnace comprises a cylinder and has a burner to 
supply heat. The fine solid particles are introduced into this cylinder 
and heated to expand the fine particles. An airstream passes through the 
horizontal cylinder and the expanded particles, which have a low density, 
are carried out of the furnace in the airstream and collected in a bag 
house or a cyclone. 
The source of heat or the source of heat energy is a gas, such as natural 
gas. This gas is burned to supply the heat energy which is used to expand 
the solid particles. There is also used liquified petroleum gas or a 
mixture of propane-butane. The quantity of heat energy required to heat a 
ton of solid perlite particles to form an expanded perlite particle is in 
the range of about 3 million to 4.5 million BTU's per ton. It is my 
understanding that with these three furnaces, viz., the rotary furnace, 
the horizontal stationary furnace, and the vertical furnace, that the 
products which can be heat treated are zeolite, vermiculite, and perlite, 
and products of that class. It is not possible to heat treat diatomaceous 
earth, clay, cement, fly ash, and titanium dioxide, for example, in the 
vertical furnace or the stationary horizontal furnace or the rotary 
furnace. 
In these furnaces, it may be considered that two types of air are 
introduced. One type of air is for combustion purposes so that the fuel, 
such as a hydrocarbon gas, can be burned to give off heat energy. The 
second type of air can be considered to be an expansion air. The expansion 
air, along with the particles to be expanded, is heated to be able to 
carry away the expanded solid particles or the expanded perlite. Because 
of the necessity of heating the expansion air, a considerable amount of 
heat energy is used. The expansion air, at ambient temperature, enters 
into the furnace, is heated and the temperature elevated to that 
temperature in the furnace, and this heated expansion air used to carry 
away the expanded solid products and then the heated expansion air is 
exhausted to the atmosphere. In one manner of thinking, the heating of the 
expansion air is a waste of heat energy. As a result of my having worked 
with these furnaces and having worked in the industry for expanding 
zeolite, vermiculite, perlite, and the like, I have become familiar with 
the industry and consider that if a furnace could be devised to eliminate 
the expansion air, then the heat energy required to make the expanded 
solid particle would be reduced and there would be a saving in energy. 
Therefore, I have devised a furnace which can be used for expanding 
zeolite, vermiculite, perlite, and can process diatomaceous earth, clay, 
cement, fly ash, titanium dioxide, pumice, and the like, and which furnace 
uses, essentially, only air for burning the combustible fuel and does not 
require expansion air for carrying away the expanded solid particles. 
THE GENERAL DESCRIPTION OF THE INVENTION 
This invention comprises a furnace having two opposed sets of refractories. 
The refractory may be furnace brick. These refractories are arranged in 
two circular paths. There is a lower refractory in a circular path and an 
upper refractory in a circular path with the upper refractory being 
positioned above the lower refractory. There is a means for rotating one 
of these refractories. Generally, the lower refractory is rotated. Also, 
there is means for introducing solid particles onto the lower refractory 
so the solid particles can be heat treated and, in certain instances, 
expanded. Also, there is a means to remove the expanded solid particles 
from the lower refractory and from the furnace. 
The refractory can be porous so that a gaseous fuel can pass through the 
refractory and burn near the surface of the refractory. The furnace 
requires, essentially, only combustible air for burning the combustible 
fuel. The furnace does not need expansion air as the expanded solid 
particle or the heat treated particle is not removed from the furnace by 
means of expansion air. The expanded solid particle or the heat treated 
particle is removed from the furnace, mainly, by force of gravity. 
In certain instances, it is possible to use a solid fuel, such as coal, or 
to use a liquid fuel, such as fuel oil and to vaporize the liquid fuel 
prior to introducing it into the furnace. 
With the furnace requiring, essentially, only combustible air for burning 
the combustible fuel, there is a saving in heat energy and fuel as it is 
not necessary to heat expansion air and fuel is not wasted in heating the 
expansion air. 
THE OBJECTS AND ADVANTAGES 
One of the objects and advantages of this invention is the provision of a 
furnace which is, relatively, small and compact for the quantity of 
product produced by the furnace; another important advantage is the 
provision of a furnace which, for a unit of product, uses less fuel than 
is used with the present, commercially, available furnaces for heat 
treating and expanding particles; another object is to provide a furnace 
which, as compared with commercially available furnaces, has a lower 
initial cost; an additional object is to provide a furnace which has a 
high output of product for a unit volume of the furnace; another object is 
to provide a furnace having refractories which are arranged in a circular 
pattern for ease of introducing raw material into the furnace and for ease 
of removal of the heat treated product from the furnace; a further object 
is to provide for a, relatively, short residence time in the furnace; to 
provide a furnace requiring a, relatively, small number of accessories; to 
provide a furnace which is capable of realizing a higher temperature than 
with a present commercially available furnace; to provide a furnace having 
opposed heating surfaces so that there is a beneficial effect from 
radiation, to provide a furnace with two sets of refractories and which 
refractories are opposed to each other and facing each other; to provide a 
furnace having a first refractory which is porous and permits fuel to flow 
through the refractory and burn in close proximity to said refractory; to 
provide a furnace having a second refractory which is heated by radiation 
from the fuel burning near said first refractory; to provide a furnace for 
utilizing incoming air for combustion purposes and to minimize incoming 
air needed for expansion purposes of expanded solid particles; to provide 
a furnace wherein the material in the furnace can be elevated from ambient 
temperature to about 2000.degree. F. in, approximately, 5 minutes; to 
provide a furnace wherein the refractory rotates in a circle; to provide a 
furnace wherein the rotational speed of the refractory can be varied for 
accommodating raw material of different characteristics; to provide a 
furnace wherein the temperature in the furnace of, approximately, 
2600.degree. F. can be realized; to provide a furnace wherein raw material 
can be fed, continuously, to the furnace and also the product discharged, 
continuously, from the furnace; to provide a furnace wherein refractory 
brick of substantially the same characteristics are used; to provide a 
furnace wherein the ends and sides of the refractory brick are sealed to 
direct the flow of the gaseous fuel through the main part of the 
refractory brick; to provide a furnace wherein refractory brick is placed 
in a side-by-side relation and the space between adjacent refractory brick 
is sealed; to provide a furnace wherein the exposed surface of the 
refractory brick is coated with porous aluminum oxide; to provide a 
furnace wherein raw material can be expanded to make an aggregate for 
light-weight concrete; to provide a furnace requiring lower capital 
investment as less pollution controls are required; to provide a furnace 
which can accommodate various fuels such as a solid fuel, a liquid fuel, 
and a gaseous fuel; to provide a process where less air is used and less 
fuel used as compared with the commercially available processes for heat 
treating particles and for expanding particles; to provide a process for 
producing expanded particles of, comparatively, very large size; to 
produce a stronger expanded product than can be produced with, presently, 
commerically, available processes in that the expanded product can be 
annealed; to provide a process for making a shielded encapsulated 
radioactive material; to expand larger particles to make strong expanded 
particles which were not, previously, commerically possible as large 
expanded particles were soft; to expand large particles without suspending 
the large particles in air; to expand small particles and to collect the 
expanded particles in a gaseous stream; to expand particles without the 
necessity of drying the particles to a moisture content of less than about 
1% moisture; to expand particles of the moisture content up to about 10% 
moisture; to provide a process wherein there is a variable residence time 
to heat treat solid particles and to accommodate solid particles with 
different characteristics; to process a radioactive material and particles 
and to encapsulate said radioactive material in a particle to store in a 
safe manner; to process radioactive salt cake with particles to 
encapsulate said radioactive salt cake and particles; to process said 
encapsultated radioactive salt cake so as to retrieve the radioactive 
material; to process radioactive salt cake with particles to encapsulate 
the radioactive salt cake and to shield the radioactive material; to 
process the shielded radioactive salt cake so as to retrieve the 
radioactive material; to process solid particles to make an expanded solid 
particle to be used as a light weight aggregate in concrete; to heat treat 
solid particles which, prior to my invention, could not be heat treated; 
to process radioactive material so as to make the material into a form 
which is not leachable and which form is easier to store; to agglomerate 
small particles into larger particles so as to achieve a more precise 
control of bed thickness in a furnace and to realize a faster and more 
efficient heat transfer to the agglomerated larger particles; to process 
waste material to make useful products; to agglomerate fines and to 
process said agglomerated fine to make useful products; and, to heat treat 
and also to expand particles with various fuels such as a solid fuel, a 
liquid fuel, and a gaseous fuel. 
These and other important objects and advantages of the invention will be 
more particularly brought forth upon reference to the detailed description 
of the invention, the appended claims and the accompanying drawings.

THE SPECIFIC DESCRIPTION OF THE INVENTION 
One part of this invention comprises a furnace for heating a material to 
form a heated product and/or an expanded or bloated product. The furnace 
comprises a first circular member 30 and a second circular member 32. 
In FIG. 2, it is seen that the first circular member 30 is in the 
configuration of a torus having a central opening or passageway 34. 
In FIG. 3, it is seen that the second circular member 32 is in the 
configuration of a torus having a central opening or passageway 36. 
In FIG. 1, it is seen that the first circular member 30 is positioned below 
the second circular member 32. The first circular member 30 can rotate and 
the second circular member 32 can be stationary. 
The first circular member 30 comprises a plenum chamber and also a support 
for fire brick 38. 
In FIG. 6, there is illustrated the support structure for the fire brick 38 
of the first circular member 30. It is seen that there is a bottom support 
plate 40 in the configuration of a torus. Then, there is an outer circular 
wall 42. There is also an inner circular wall 44 defining the opening 34. 
Also, there are two in-between circular wall supports 46 near the wall 42 
and 48 near the wall 34. Projecting inwardly on the upper part of the wall 
42 is a support ledge 50. And, projecting inwardly of the wall 44 is a 
support ledge 52. Then, on the upper part of the wall 46 is a support 
ledge 54 and on the upper part of the wall 48 is a support ledge 56. The 
firebrick 38 rests on the support ledges. In FIG. 2, it is seen that there 
are three circular courses of brick. There is an outer circular course of 
brick 56, a middle course of brick 58, and an inner circular course of 
brick 60. 
In FIG. 2, it is seen that the firebrick 38, in a plan view, are in the 
figure of the frustum of a trapezoid. The firebrick in the outer course 76 
are larger in size than the first brick in the middle course 58. The 
firebrick in the middle course 58 are of a larger size than the firebrick 
in the inner course 60. It is to be understood that a furnace may have 
only one course of firebrick or may have a large number of courses of 
firebrick. For illustrative purposes, there is illustrated in the first 
circular member 30 three courses of firebrick. 
There are four upright pedestals 60, spaced at 90.degree. with respect to 
each other. Each of the pedestals 60 has a supporting foot 62. Also, on 
the upper end of each of the pedestals 60, there is an inwardly directed 
shaft 64 and a roller 66 is positioned on the shaft. In FIGS. 1 and 6, it 
is seen that the bottom support plate 40 rests on the rollers 66 and that 
the first circular chamber 30 can rotate on these rollers 66. Further, on 
the upper part of the upright pedestals 60, there is an upwardly directed 
shaft 68. There is positioned on the upwardly directed shaft 68 a roller 
70. In FIGS. 1, 2, and 6, it is seen that the outer circular wall 42 is 
positioned between the four rollers 70. The first circular member 30 can 
rotate between the rollers 70 and can be positioned by these rollers 70. 
In FIGS. 1, 2, and 6, there is illustrated a feed system for feeding an 
air-combustible gas mixture, such as propane or butane, to the plenum 
chamber of the first circular member 30. In FIG. 6, the plenum chamber is 
identified by reference numeral 72. 
There is an inlet pipe 74 connecting with a mixing chamber 76. The mixing 
chamber 76 has an outlet nozzle 78. 
There is an adapter 80 which fits over the outler nozzle 78. The adapter 
connects with two arms 82 and 84. In FIG. 6, it is seen that the arm 82 
connects with an opening 86 in the bottom support plate 40. Likewise, the 
arm 84 connects with another opening in the bottom support plate 40. The 
arms 82 and 84 are welded to the bottom support plate 40. 
There is attached to the adapter 80 a sprocket 88. Also, positioned near 
the mixing chamber 76 is a motor and variable drive gear box 90 having 
outlet shaft 92. On the outlet shaft 92, is a sprocket 94. A chain 96 
connects the sprocket 88 and the sprocket 94. With the actuation of the 
motor and variable drive gear box 90, the sprocket 94, the chain 96, and 
the sprocket 88 move so as to rotate the adapter 80 and the arms 82 and 84 
and the first circular member 90. 
With the rotation of the sprocket 88 and, correspondingly, the first 
circular member 30, the material placed on the firebrick also rotates. 
The firebrick 38 is a porous brick and allows the mixture of air an 
combustible gas to pass from the plenum chamber and through the 
interstices of the brick to the surface of the brick. From experience, I 
have found that the ends and sides of the firebrick 38 should be painted 
with a "temperature resistant" paint or a fireproof paint 100. This paint 
is impervious to the flow of the air-combustible gas mixture and thereby 
restricts the flow of the air-combustible gas mixture to passing through 
the brick. In placing the brick 38 on the support ledges, there is used a 
silicone sealant 102 to seal between the surface of the brick and the 
surface of the ledge. 
The firebrick may be one of many suitable bricks, such as K30 B and W. 
There may be placed on top of the firebrick, a layer 104 of aluminum oxide 
or silicone carbide. The porosity of the layer 104 of aluminum oxide or 
silicone carbide is of the same porosity as of the firebrick 38. The layer 
104 is harder than the firebrick 38 so as to resist abrasion. Further, I 
consider that it is desirable that the firebrick 38 be as uniform as 
possible with respect to dimension and with respect to weight. It is 
possible within a narrow tolerance range to have the firebrick 38 in a 
course of the same general dimensions with respect to length, width, and 
thickness and also the same general porosity. Naturally, the firebrick 38 
will vary in dimensions from one course to another course but in the same 
course, the firebrick should be of the same general characteristics. 
The second circular member 32 comprises a number of refractory brick 110 
positioned above the firebrick 38 of the first circular member 30. In FIG. 
1, it is seen that there is an upper circular ring 112. The refractory 
brick 110 are suspended from the ring 112 by means of bolts 114. In FIG. 
1, it is seen that the spacing between the refractory brick 110 and the 
firebrick 38 remains constant. 
In FIG. 1, it is seen that on the outside of the refractory brick 110 and 
the second circular member 32 that there is a depending circular rim 116. 
The depending circular rim 116 assists in maintaining the material being 
processed between the firebrick 38 and the refractory brick 110. 
In FIG. 7, there is illustrated the upper circular ring 112 and bolts 114 
connecting with the refractory brick 110. In FIG. 7, it is seen that the 
length of the bolts 114 vary so as to have some of the refractory 110 
farther away from the ring 114 than other refractory brick. The result is 
that some of the refractory brick 110 are closer to the firebrick 38. The 
reason for this is that when the material to be processed is initially 
placed on the firebrick 38, it is of a, relatively, small volume. After a 
while, this material expands into a larger volume and in order to 
accommodate the larger volume, the refractory brick 110 must be positioned 
farther away from the firebrick 38. In FIG. 7, it is seen that the 
refractory brick 110 have a recess 118. There is a nut 120 screwed onto 
the threaded end of the bolt 114 and in said recess 118. 
In FIG. 8, there is illustrated a split upper ring 122. The split upper 
ring is in the form of a spiral having a lower end 124 and a upper end 
126. A number of bolts 114 connect with the ring 122 and also connect with 
and support the refractory brick 110. In FIG. 8, the bolts 114 can be of, 
substantially, the same length even though some of the refractory brick 
110 are positioned closer to the firebrick 38 than some of the other 
refractory brick 110. Again, the spacing of the refractory brick 110 with 
respect to the firebrick 38 is to accommodate the various size and volume 
of the material being processed. 
In FIG. 3, it is seen that there is a void 130 between two adjacent 
refractory brick 110 so as to allow material to be introduced between the 
second circular member 32 and the first circular member 30. This is more 
clearly illustrated in FIG. 4 wherein it is seen that there is a chute 132 
or conveyor 132 for introducing product onto the firebrick 38. It is to be 
remembered that the lower circular member 30 and the firebrick 38 rotate 
while the upper circular member 32 and the refractory brick 110 as 
stationary or do not rotate. With the opening of void 130 in the upper 
circular member 32, the material to be processed can be introduced by 
means of the chute 132 so as to fall onto the firebrick 38. In FIG. 4, it 
is seen that the lower circular member 30 rotates in a clockwise 
direction. Also, in FIG. 4, it is seen that there is a doctor blade 134. 
The doctor blade extends to the outer edge or periphery of the lower 
circular member 30 so as to cause the processed material to flow toward 
the periphery of the member 30. There is positioned, partially, under the 
member 30 a sloping conveyor or chute 136. The material which has been 
processed is forced by the doctor blade to fall onto the chute 136 and be 
removed from between the firebrick 38 and the refractory brick 110. 
In FIG. 7, it is seen that there is an opening 130 between the adjacent 
refractory brick 110 attached to the circular ring 112. Likewise, in FIG. 
8, it is seen that there is an opening 130 between firebrick 110 attached 
to the split circular ring 122. The openings 130 illustrated in FIGS. 7 
and 8 make it possible to introduce the material to be processed onto the 
firebrick 38 of the lower circular member 30. 
In FIG. 11, there is illustrated the doctor blade 134 positioned above the 
firebrick 38 and positioned so as to drop the product 138 onto the sloping 
conveyor 136. 
In FIGS. 1 and 2, it is seen that there are spaced apart pedestals 140, on 
the outside of the upright pedestal 60. On the lower part of the pedestal 
140, there is a foot 142. On the upper part of the pedestals 140, there is 
a flange or arm 144. There depends from the flange or arm 144 a support 
146, such as a bolt or a rod. The bolt or rod 146 also connects with the 
upper circular 112 or the split ring 122 so as to support the ring and the 
refractory brick 110 above the firebrick 38. 
In FIGS. 1 and 3, there is illustrated an exhaust system for the products 
of combustion and, possibly, some of the resulting product from the 
process. In FIGS. 1 and 3, it is seen that there is a hood 150 positioned 
above the opening 36 in the upper circular member 32. The hood 150 
connects with the exhaust pipe 152. It is possible to exhaust the gases 
from the furnace 28 through the exhaust pipe 152 and into the atmosphere. 
Sometime, it may be desirable to separate entrained solids in the exhaust 
gases. Therefore, there is illustrated in FIG. 1, in broken line or 
phantom line, a cyclone 154 which connects with the exhaust pipe 152 by 
means of an inlet pipe 156. The cyclone 154 has a lower exhaust pipe 158. 
On the upper end of the cyclone 154, there is a motor-van-passageway 160 
for directing the exhaust gases from the cyclone 154 and into a bag house 
162. It is seen that some of the solid particles in the exhaust gases are 
separated in the cyclone 154 and flow out of the cyclone through the 
exhaust 158. Also, the gases which flow from the cyclone 154 into the bag 
house 162 can flow out of the bag house. The bag house will remove the 
small particulate solids in the exhaust gases. 
In FIG. 16, there is illustrated another species of a lower circular member 
170. It is seen that this species comprises a bottom support plate 172 
surrounded by an upwardly directed circumscribing rim 174. Further, it is 
seen that positioned on the lower support plate 172 are a number of flat 
bars 176 having bends 178. These flat bars can be positioned on edge on 
the plate 172. In the zigzag flat bars 178, there may be passageways 180. 
There is positioned on top of the zigzag bars 178, expanded metal 182. 
Then, there is positioned on top of the expanded metal 182, firebrick 184. 
The firebrick 184 may have the sides and ends painted with a high 
temperature fire resistant paint so as to seal the firebrick. Further, the 
tops of the firebrick 184 may be coated with a block of aluminum oxide or 
silicone carbide of substantially the same porosity as the firebrick 184. 
The reader is to understand that the firebrick 184 are porous and that the 
mixture of air and combustible gas can pass through the porous firebrick 
184 and also the coating of aluminum oxide or silicone carbide so as to be 
able to burn on top of the firebrick 184. It is to be understood that that 
part of the lower circular member 170 between the lower plate 172, the 
outer circumscribing rim 174, the inner circumscribing rim 186, and the 
lower part of the firebrick 184 is a plenum chamber 188. There can be 
introduced into the plenum chamber 188, the air and combustible gas 
mixture. To introduce the air and combustible gas mixture into the plenum 
chamber 188, there are four arms 190 connecting with the outlet nozzle 78 
of the mixing chamber 76. The four arms 190 may be square tubes. In the 
lower plate 172, there are a number of openings 192. Aligned with the 
openings 192 in the plate 172 are openings 194 in the tubes 190. The tubes 
190 can be welded to the lower plate 172 so as to form a rigid structure 
with the openings 192 and the openings 194 aligned for introducing the 
air-combustible gas mixture into the plenum chamber. Again, it is to be 
realized that the lower circular member 170 rotates as does the lower 
circular member 30 as, previously, explained in a foregoing part of this 
written description. 
One of the advantages of the lower circular member 170 is the firebrick 184 
need not be cut into a trapezoidal configuration. There is a saving in 
time and money by using standard fire brick 184. The firebrick 184 are 
supported on the expanded metal 182 which, in turn, is supported on the 
lower support plate 172. The lower support plate 172 is supported by the 
rollers 66, see FIG. 1, and the description of the rollers 66. Further, 
the lower circular member 170 is prevented from a sideways motion by the 
rollers 70 positioned on the upright pedestal 60. 
In FIGS. 17 and 18, there is illustrated an upper circular member 200 
having a central opening 202. The upper central member 200 comprises sheet 
metal 204 in the configuration of a spiral, see FIG. 18. Sheet metal 204 
is not continuous as there is a break to form an opening 206. 
There is attached to the sheet metal 206 refractory brick 208. The 
refractory brick 208 can be attached by means of sheet metal screws 210 
and an adhesive 212. Also, there is on the periphery of the sheet metal 
204, and depending therefrom, a circumscribing depending rim 214. This rim 
214 assists in maintaining the product in the furnace 28 between the 
rotating lower circular member and the upper stationary circular member. 
Again, the opening 206 is to allow material to be introduced onto the 
rotating lower member. 
An advantage of the upper circular member 200 is that it is not necessary 
to cut the refractory brick into the configuration of a frustum of a cone, 
see refractory brick 110 in FIG. 3. The refractory brick 208, in the main, 
can be standard, commercially, available brick. The use of this standard 
brick results in a less expensive upper circular member 200. Also, the 
sheet metal 204 can be shaped into the form of the split circular spiral. 
The material 220 to be processed can be positioned on the chute or conveyor 
132 and then placed on the firebrick of the first circular member, see 
FIG. 4. In FIG. 4, it is seen that this first circular member rotates in a 
clockwise direction and that the material is processed into semiprocessed 
material 222. After the material has been further processed into a product 
224, the material can be removed from the lower circular member by means 
of doctor blade 134. The product 224 will fall onto the chute 136 for 
further treatment, such as packaging, or for use, such as in light weight 
concrete, gardens, insulation, filter aid, and the like. 
Some of the material which can be processed in this furnace 28 are perlite, 
vermiculite, volcanic ash, pumice, zeolite, clay, diatomaceous earth, 
carriers for radioactive materials, titanium dioxide, salt cake, and the 
like. 
The furnace 28 can achieve a temperature in the range of about 2500.degree. 
to 2600.degree. F. This is a sufficiently high temperature to process 
these materials. 
It is possible to introduce the material 220, viz., perlite, vermiculite, 
volcanic ash, pumice, and zeolite into the furnace 28. This material 220 
on the firebrick will be heated and expand. For example, the density of 
the perlite 220 being introduced into the furnace 28 may be in the range 
of about 80 pounds per cubic foot while the density of the processed 
perlite 224 or expanded perlite 224 may be in the range of 5 pounds to 10 
pounds per cubic foot. For example, the expanded perlite may have a 
density in the range of 3 pounds to 4 pounds per cubic foot and may range 
in particle size from +50 mesh to -100 mesh. Perlite in the range of 15 to 
20 pounds per cubic foot may have a particle size of about 5/8 of an inch. 
I have found that it is not necessary to use a flux with perlite. The 
perlite can be expanded without the use of a flux, such as sodium 
carbonate, potassium carbonate, sodium oxide or potassium oxide. With the 
operation of the furnace 28, I have noticed that the perlite is, 
apparently, annealed and is stronger or tougher than expanded perlite made 
in a rotary furnace or a verticle furnace. The use of the expanded perlite 
can be for purposes of insulation, a filter aid for food products, an 
aggregate in light weight concrete, and a soil conditioner for 
horticultural purposes. 
Vermiculite can be treated in a manner similar to the treatment of perlite. 
Vermiculite is a schist and comprises a mixture of vermiculite and 
hornblend. The vermiculite ore can be passed through a rotary dryer and 
then screened to a size in the range of 1/8 inches to +40 mesh to form the 
material 220 to be expanded. The vermiculite 220 is introduced into the 
rotary furnace 222 and processed to form the processed vermiculite 224. 
The processd vermiculite 224 is softer than the processed perlite 124. 
However, the processed vermiculite can be used for purposes of insulation 
and as an aggregate in the formation of insulation board. It is possible 
to saw the insulation board, nail the insulation board, and use the 
insulation board in building a structure, such as a house or a shop. 
In addition to expanding or bloating materials, such as perlite and 
vermiculite, in the furnace 28, this furnace can also be used for 
calcining materials. For example, materials 220 which can be calcined are 
diatomaceous earth, clay, cement, titanium dioxide, fly ash, volcanic ash, 
natural zeolites, and pumice, to name a few. Many of these materials are 
of such a small size, even approaching the size of powder, it is not 
reasonable to process these materials in the furnace 28. In order to 
process these materials, it is necessary to add a binder to make the 
material somewhat sticky to form a sticky material. Then the sticky 
material is placed on a screen or a similar device and agitated to cause 
the sticky material to ball up or to agglomerate so as to form an 
agglomerated material. In this process of forming the agglomerated 
material, the particle size can be, readily, controlled. The 
transformation of the powder material to a larger and specific particle 
size by the agglomeration process allows precise control of the bed 
thickness of the material 220 on the fire brick of the furnace 28. 
To make the agglomulated product, there is employed a binder. The binder 
can be one of many chemicals or a combination of chemicals varying from 
plain water to complex chemicals depending upon the requirements of the 
material being treated. For example, in the calcining of diatomaceous 
earth for filter aid products, there is added to the diatomaceous earth a 
sodium flux, such as sodium carbonate. However, other sodium compounds can 
work as well as sodium carbonate, such as sodium hydroxide, sodium 
chloride, sodium silicate, and corresponding potassium compounds. One of 
the fluxes can be in liquid form such as sodium carbonate diluted with 
water. In the case of the calcining of clay, the addition of water as a 
binder and then the balling up or agglomeration of the clay can be 
achieved. The agglomulated clay particles will hold together long enough 
to satisfy the bed thickness requirement in the furnace 28. In certain 
instances, where higher heat requirements might be needed, they can be 
achieved with the use of air and a natural gas combustion mixture; the 
binder can be a fuel, either liquid or solid. For example, in the 
processing of cement, there may be mixed coal and cement and an oxidizing 
agent to form the agglomerated product. The coal is burned in the furnace 
28 and the ash from the coal can become integrally mixed with the cement. 
If the ash from the coal is detrimental to the product 224 from the 
furnace 28, then liquid petroleum can be used as the binding agent in the 
agglomeration process. The oxidizing agent may be a potassium chlorate. 
In the calcining of these materials, the step of forming agglomerated 
products is important. Be being able to have the agglomerated products 
within a certain range of sizes or within a certain size range, it is 
possible to control the thickness of the material 220 on the firebrick. 
This makes possible a more precise control of heat transfer to the 
material 220. The heat transfer to the material 220 can be quicker and 
easier for a controlled bed thickness as contrasted with a bed thickness 
which is not controlled. Also, a more uniform processed product 224 can be 
realized with a controlled bed thickness of the material 220. 
The finely divided material and the powder which have been processed to 
make an agglomerated product 220 can be further processed in the furnace 
28 to calcine the agglomerated product. In calcining the agglomerated 
product 220, the product is heated to a high temperature without fusing 
the product 220 to make the processed product 224. In the calcining 
operation, the agglomerated product 220 undergoes changes, such as 
oxidation, and also changes, such as forming a smooth or glasslike surface 
on the processed product 224. 
An example will assist in explaining the agglomerating process and also the 
calcining process. A suitable subject is diatomaceous earth which is a 
nonmetallic mineral composed of about 80% to 90% amorphous silica. The 
silica is the skeletal remains of diatoms in the ocean, millions of years 
ago. The crude diatomaceous earth is mined by open pit methods and 
transported to a plant site. The mined, crude diatomaceous earth is 
crushed, dried, and then pulverized and foreign material separated. At 
this stage of the process, the crushed diatomaceous earth will pass 90% 
through a 325 mesh screen (44 microns). The crushed diatomaceous earth is 
mixed with a flux. The flux can be sodium carbonate or sodium silicate, or 
sodium oxide, or potassium carbonate or potassium oxide, or postassium 
silicate. It is advantageous to mix the flux with water to form a liquid 
flux. The liquid flux is mixed with the crushed diatomaceous earth and 
formed into the agglomerated product 220. Then, the agglomerated 
diatomaceous earth 220 can be introduced into the furnace 28 and heated to 
form the processed diatomaceous earth product 224 which has a glaze or a 
glassy surface on the individual agglomerated particles. In the furnace 
28, the sodium in soda ash reacts with the silica of the diatomaceous 
earth at a temperature of about 1850.degree. F., to form the product 224. 
Similarly, fine particles of clay can be mixed with water and processed to 
form agglomerated clay. The agglomerated clay 220 can be introduced into 
the furnace 28 and heated and processed to form agglomerated clay products 
224, which have a smooth or glassy like surface. 
Similarly, fine particles of titanium dioxide, fly ash, volcanic ash, 
cement, natural zeolite, pumice, and the like can be mixed with a flux, 
such as a sodium salt like sodium carbonate or sodium silicate or a 
potassium salt like potassium carbonate or potassium silicate and formed 
into agglomerated products 220 which can be introduced into the furnace 28 
to form a processed product 224 having a smooth or glassy surface. 
The calcined clay has a higher brightness and opacity than natural clay and 
therefore is valuable in the manufacture of high-gloss paper. The calcined 
clay has better hiding power in the high-gloss paper. 
A calcined diatomaceous earth, calcined in the temperature range of about 
1750.degree.-1900.degree. F. can be used as a filter aid, used as a filler 
in paint and also used as a filler in paper. 
In regard to diatomaceous earth which is used as a filter aid, the 
calcining process can be valuable in rejuvinating the filter aid. For 
example, the filter aid comprising spent diatomaceous earth can be 
processed and mixed with a binder, such a sodium silicate to form an 
agglomerated product 220 in the form of a discrete unit or a ball. Then, 
this discrete unit or ball 200 can be introduced into the furnace 28 and 
heated to a temperature in the range of about 1750.degree.-1900.degree. F. 
to form a new filter aid comprising the glazed or glassy diatomaceous 
earth ball or discrete unit. A result of this is the reusing of 
diatomaceous earth and the elimination of the step of throwing away used 
diatomaceous earth which has served a purpose as a filter aid. 
In addition to being able to calcine volcanic ash and pumice, it is also 
possible to expand the volcanic ash and pumice in the furnace 28 in the 
same manner that perlite and vermiculite are expanded, as above disclosed. 
Further, zeolite can be expanded in the furnace 28 and also can be 
calcined in the furnace 28. 
In FIG. 12, there is illustrated a process for treating radioactive 
material so that the radioactive material can be stored. 
Radioactive material 230 and solid particles 232, such as diatomaceous 
earth, clay, cement, fly ash, volcanic ash, natural zeolites, and pumice, 
are mixed together at step 234 to form a mixture of agglomerated product. 
Then, at step 236, the agglomerated product or mixture is calcined to form 
a solid encapsulated material. The encapsulated material comprises the 
radioactive material and the solid particles. The encapsulated material 
can be stored at step 238. Or, the encapsulated material can be mixed with 
a shielding material, such as lead or boraxo or polyethylene at step 240 
to form a shielded encapsulated material comprising the radioactive 
material. In this manner, there are prepared small, discrete, solid 
particles comprising radioactive material and which small, solid, discrete 
particles can be coated with a shielding material to lessen the radiation 
from the small, discrete particles. The shielded encapsulated material can 
be stored at 242. 
The process of FIG. 12 makes it possible to transform the radioactive 
material, usually in a liquid form, into a solid and then to coat the 
solid with radioactive shielding material so as to make it possible to 
more, safely, store the radioactive material. 
In FIG. 13, there is illustrated a process for treating objects 250 
contaminated with radioactive material. For example, objects 250 which are 
contaminated with radioactive material are paper, clothing, gloves, 
rubber, plastic and the like which are used in the area of radioactive 
material. In this process, the objects 250 can be frozen at step 252 to 
form a solid frozen object. The objects 250 may be frozen by being 
contacted with liquid nitrogen so as to form a brittle, solid, frozen 
object. 
Then, in step 254, the brittle, solid, frozen object can be comminuted to 
small pieces. The brittle, solid, frozen objects may be comminuted in a 
ball mill or hammer mill or appropriate apparatus. The solid, frozen 
objects are processed at step 256 by burning so as to leave a radioactive 
residue which can be collected. The radioactive residue may be trapped in 
stack gases by a filter. It is to be remembered that radioactive particles 
are discrete particles and are not gases. The radioactive particles are 
solid and therefore can be trapped by a filtering means. Further, the step 
256 reduces the volume of the objects containing the radioactive material. 
Prior to steps 252, 254, and 256, the volume of the objects containing the 
radioactive material was quite large. With these steps, the volume of the 
radioactive material is reduced to a more manageable volume. 
The radioactive residue 258 is mixed with a solid 260. The solid 260 may be 
a chemical which can be calcined, for example, diatomaceous earth, clay, 
cement, titanium dioxide, fly ash, volcanic ash, natural zeolites, pumice, 
and the like. At step 262, the radioactive residue and the solid 260 are 
mixed to form a mixture 264. The mixture 264 may be stored at 266. 
The mixture 264 may be calcined in the furnace 28, see step 268, to form a 
calcined mixture. The calcined mixture has a smooth or glossy appearance 
and is a solid. The calcined mixture in step 270 can be mixed with a 
shielding material, such as lead, boraxo, polyethylene and the like to 
form a shielded calcined material. At step 272, the shielded calcined 
material can be stored. The shielded calcined material is a solid and the 
radioactive waste is stored as a solid. The shielding of the radioactive 
waste lessens the radiation escaping into the surrounding atmosphere from 
the radioactive waste. 
The calcined mixture from step 268 can be stored at 274. 
If the solid 260 be perlite or vermiculite or volcanic ash or pumice, then 
the mixture 264 can be processed in the furnace 28 at step 276 to form an 
encapsulated, radioactive residue. The radioactive residue can be stored 
at step 278. The encapsulated, radioactive residue is a solid and can be 
easily handled in the solid form. At step 280, the encapsulated, 
radioactive residue can be mixed with a shielding material, such as lead, 
borax, or polyethylene to form a shielded, encapsulated, radioactive 
material. The shielded, encapsulated, radioactive material can be stored 
at step 282. In FIG. 13, it is seen that there has been provided a process 
for treating an object contaminated with the radioactive material and then 
to store the resulting radioactive residue either in a calcined form or in 
an encapsulated form. In both the calcined form and the encapsulated form, 
the radioactive residue is a solid and can be, readily, handled. 
In FIG. 14, there is illustrated a process for processing salt cake 300. 
Salt cake comprises radioactive material and may be a solid, a liquid, and 
a mixture of solids and liquids. In the processing step, salt cake 300 is 
mixed with clay 302 to form agglomerated particles. These agglomerated 
particles can be classified as to size and introduced into the furnace 28. 
In the furnace 28, the agglomerated particles of clay and salt cake can be 
heated to form calcined particles 306. These calcined particles 306 are a 
solid and have a glassy or glossy appearance. It is to be remembered that 
these calcined particles 306 are discrete units of, substantially, the 
same size as the agglomerated particles formed by mixing the clay and salt 
cake. At step 308, the calcined particles can be stored. At a desirable 
time, the calcined particles 306 can be taken from storage 308 and 
processed in step 310 to form retrieved radioactive material 312. The 
retrieved radioactive material 312 may be used in a suitable and desirable 
manner. 
Instead of storing the calcined particles 306, it may be desirable in step 
314 to coat these calcined particles with a shielding material 316. The 
shielding material may be lead, borax, polyethylene, to name a few 
suitable shielding materials. The coating of the calcined particles of the 
shielding material results in shielded particles 318. The shielded 
particles 318 are safer to store than the calcined particles 306 and are, 
therefore, more easily stored than the calcined particles 306. At a 
suitably desirable time, the shielded particles 318 can be processed at 
step 320 to form retrieved radioactive material 312. 
In FIG. 15, there is illustrated the process of mixing a particle 330 with 
a binder 332. As previously stated, the particle may be diatomaceous 
earth, clay, cement, titanium dioxide, fly ash, volcanic ash, natural 
zeolites, pumice, to name a few. The binder may be water, sodium 
carbonate, sodium silicate, sodium oxide, potassium oxide, potassium 
carbonate, potassium silicate, to name a few suitable binders. At step 
334, the particle 330 and the binder 332 may be mixed to form a mixture 
and then the mixture agglomerated to a suitable particle size to form an 
agglomerated mixture 336. 
The agglomerated mixture 336 may be introduced into the furnace 28 and the 
agglomerated mixture calcined at step 338. As previously explained, in the 
calcining of the agglomerated mixture, there is formed glossy or glassy or 
smooth particles identified as a calcined mixture 340. The calcined 
mixture 340, has previously been referred to as the processed product 224 
and the agglomerated mixture has previously been referred to as the 
agglomerated product 220. 
In FIG. 4, the doctor blade 134 need not touch the firebrick of the lower 
circular member 30 but, instead, can be an air doctor blade for blowing or 
moving the product 224 across the firebrick and toward the sloping 
conveyor 136 for removal from the vicinity of the furnace 28. 
One of the advantages of the furnace 28, as compared with a rotary furnace 
or a vertical furnace or a horizontal stationary furnace is that less air 
is required in the furnace 28 than with any of the other furnaces. For 
example, with the furnace 28, the air required is the air of combustion to 
burn the fuel. There is no need to heat extraneous air for removing the 
expanded product, such as bloated perlite or bloated vermiculite or 
bloated volcanic ash or bloated pumice from the furnace. In the other 
furnaces, air is needed for both combustion and the removal of the bloated 
product from the furnace. With the furnace 28, it is possible to heat the 
furnace to a temperature of about 2000.degree. F. in approximately 5 
minutes. 
With the furnace 28, as compared to the above enumerated furnaces, it is 
not necessary to predry the material to be processed to a moisture content 
of less than 1%. It is possible to use perlite having a moisture content 
in the range of 3% to 10%. With the above enumerated furnaces, such as a 
vertical furnace or a horizontal furnace or a rotary furnace, it is 
necessary to dry the material to be processed to a moisture content less 
than one percent. In these furnaces, the residence time is approximately 
one second. In the furnace 28, the residence time can be varied to suit 
the material to be processed and the residence time can be varied from 
about five seconds to sixty seconds. In fact, the residence time can be 
varied over a much wider range of time than from five seconds to sixty 
seconds as the residence time may be two minutes or three minutes. 
The fuel which can be used and introduced into the plenum chamber can be a 
liquified petroleum gas, propane, butane, water, gas, diesel in gaseous 
form, and the like. As previously stated, there can be admixed with the 
material to be treated a solid fuel such as coal or there can be used 
diesel as a binder in forming the agglomerated particle to be introduced 
into the furnace. 
In a rotary furnace, the fuel efficiency is approximately 10%. A highly 
efficient rotary furnace may have a fuel efficiency of 30%. With the 
furnace 28, I estimate that the fuel efficiency varies between 
approximately 60% to 85% . Again, a main reason for this difference in 
fuel efficiency is that it is not necessary to heat extraneous air in the 
furnace 28 while it is necessary to heat extraneous or carrier air in the 
rotary furnace. Another reason for the greater fuel efficiency of the 
furnace 28 is that it is not necessary to heat such a large mass as 
compared with the rotary furnace. The furnace 28 is more compact, less 
mass, smaller size, and therefore there is not a large mass of material to 
heat as compared with the rotary furnace. Also, there is less heat loss 
from the furnace 28 as compared with the rotary furnace. 
As previously stated, the furnace 28 can be used to regenerate filter aids. 
For example, a filter aid prepared from perlite or a filter aid prepared 
from diatomaceous earth can be regenerated in the furnace 28 at a 
temperature in the range of about 1500.degree. F. to 2000.degree. F. This 
results in a saving in the processing of a filter aid and also means that 
it is not necessary to discard used filter aids. 
In the furnace 28, it has been shown and described that the spacing between 
the reflector brick and the firebrick can be varied to accommodate the 
material 220 to be processed into the product 224. Initially, when the 
material 220 is introduced into the furnace 28, the spacing between the 
reflector brick and the firebrick is a small distance. This results in 
more radiant heat on the material 220. If the material 220 expands into an 
intermediate product 22, the spacing between the reflector brick and the 
firebrick is increased to accommodate the larger size. Then, near the end 
of the cycle or process, the spacing between the reflector brick and the 
firebrick is greatest to accommodate the expanded material. With this 
furnace, it has been noticed that it has been possible to expand perlite 
particles and make the particles extremely strong compared to expanded 
perlite particles from a rotary furnace or a verticle furnace or a 
stationary horizontal furnace. The expanded perlite particles from the 
furnace 28 were heavier than the expanded perlite particles from one of 
the three above-enumerated furnaces. Further, with the furnace 28, it is 
possible to expand perlite particles of comparatively large size into 
comparatively strong expanded perlite particles. This has not been 
accomplished in the perlite industry with a rotary furnace or a vertical 
furnace or a horizontal furnace. 
As previously stated, the firebricks were selected so as to be as uniform 
as possible. A standard for uniformity was that the bricks were to weigh, 
substantially, the same. Also, the bricks were painted on the ends and 
sides with a fireproof paint so as to seal the ends and sides. Then, the 
combination of air and combustible gas could be introduced into the plenum 
and this combination flow through the brick and onto the surface of the 
brick where the combination was ignited and burned. In a test, it was 
estimated that the fuel consumption was, with the furnace 28, in the range 
of 3,000,000 BTU's per ton of product, such as expanded perlite. With a 
rotary furnace or a vertical furnace or a stationary horizontal furnace, 
the fuel consumption is in the range of 4,000,000-4,500,000 BTU's per ton 
of expanded perlite. It is seen that there is a saving of approximately 
one-third to one-half of the fuel in the furnace 28 as compared with one 
of the other three furnaces. To assist in maintaining a long life for the 
firebrick, there was attached a block of porous aluminum oxide on top of 
the firebrick. One of the requisites for the aluminum oxide was that it 
would have a porosity equal to that of the firebrick. 
In the furnace 28, it is seen that the adapter 80 is free to rotate, with 
the first circular member 30, around the outlet nozzle 78. The adapter 80 
and the outlet nozzle 78 function as a swivel. The adapter 80 can rotate, 
completely, around the nozzle 78 along with the rotation of the first 
circular member 30. The gas passes through the pipe 74, mixing chamber 76, 
outlet nozzle 78, adapter 80, arms 82 and 84, or 190 and passes into the 
plenum chamber and flows through the porous brick so as to be burned on 
top of the firebrick. The material 220 to be processed is heated by 
conduction from the surface of the firebrick, by convection of gas, 
products of combustion, flowing from the firebrick to the material 220, 
and also by radiation from the reflector brick positioned above the 
firebrick and also above the material 220. The flowing of the mixture of 
air and combustible gas through the firebrick and also on top of the 
firebrick assists in keeping the material 220 being processed from 
sticking to the firebrick. The flowing gases raise or elevate the material 
being processed from the surface of the firebrick so as to lessen the 
possibility of the material sticking and adhering to the firebrick. With 
this method of burning the gas on the upper surface of the firebrick, it 
is possible to attain a temperature in the range of about 2600.degree. F. 
The material 220 is heated by radiation from the reflector brick and which 
reflector brick or which reflector may be as close as one-quarter of an 
inch to the firebrick. When the material 220 is, initially, placed on the 
firebrick, the reflectors may be as close as one-quarter of an inch to the 
firebrick. With the expansion of the material 220, it is necessary to 
position the reflectors farther away from the firebrick so as to allow the 
expanded material or processed material 222 to be carried by the rotating 
firebrick to the outlet of the furnace 28. If the reflectors were not 
positioned farther away from the firebrick, then the reflectors would 
interfere with the movement of the material 222 being processed. In 
certain instances, the reflectors may be as much as one and one-half 
inches away from the firebrick to accomodate the material being processed. 
I consider that one of the advantages of this invention is that the 
retention time of the material to be processed in the furnace 28 can be 
accurately controlled. As previously stated, the retention time can be 
varied from five seconds up to two or three minutes or even longer. The 
ability to vary the retention time makes it possible to process material 
in a manner which has not been previously processed. For example, if, 
after the particle has been expanded, the expanded particle is retained in 
the furnace or heat zone, the surface of the particle tends to fuse. This 
causes a slight shrinkage in the particle but the strength of the particle 
is greatly increased. Because the retention time in the furnace can be 
controlled, much larger particles can be expanded with the furnace 28 than 
with the other furnaces, such as the vertical furnace, the rotary furnace, 
or the horizontal furnace. Again, remember that after the particle has 
been expanded and if it be retained in the furance, an annealing process 
or a fusing of the surface of the particle takes place to increase the 
strength of the particle. This creates the possibility of making 
high-strength, light-weight conrete blocks. In the forming of expanded or 
bloated particles and also in the calcining of particles with the furnace 
28 and with my method, it is possible to expand and calcine materials 
without the necessity of drying the materials as contrasted with the 
conventional processing methods in a vertical furnace or rotary furnace or 
horizontal furnace wherein the material to be processed must be almost 
bone dry. 
As stated, air and a gas, such as liquified natural gas or propane or 
butane, can be mixed and burned on top of the firebricks to realize in the 
temperature range of about 2600.degree. F., and, it is conceivable, that 
in place of air there can be used oxygen so as to form an oxygen-natural 
gas mixture which can be burned on top of the firebrick. The heating 
process can be used for calcination of properly prepared mixtures of 
aluminal-silicate materials and radioactive waste products, primarily, 
salt cake or sodium nitrate-nitrite complex containing cesium 137 and 
other radioactive products. With calcination, there is a fusion of the 
aluminal-silicates with the radioactive product thereby causing the 
radioactive products to be encased in a glasslike matrix. The radioactive 
products become a solid, nonleachable form of material suitable for short 
term or long term storage. Again, this is of value as in many instances, 
the salt cake or sodium nitrate-nitrite complex containing cesium 137 and 
other radioactive products may be in a liquid form or may be in a 
liquid-solid combination or mixture. The salt cake or sodium 
nitrate-nitrite complex can be mixed with a calcining agent like 
diatomaceous earth, clay, cement, fly ash, volcanic ash, natural zeolites, 
pumice, and the like, to name a few and the salt cake can be used as a 
binder. Then, the resulting mixture can be made into agglomerated 
particles of desired size and then these agglomerated particles of the 
salt cake and the carrier, such as diatomaceous earth or clay can be 
calcined and fused so that a solid results and which solid contains the 
radioactive materials. A contributing factor to storing the salt cake and 
radioactive materials in solid form is the step of agglomerating the 
mixture of the radioactive materials and the diatomaceous earth or clay or 
the like into balls or discrete units of, substantially, the same size. 
With the formation of these agglomerated particles of discrete size and of 
substantially the same dimensions, it is possible to have a precise 
control of the bed thickness of the particles to be processed on the 
firebrick. The control of the bed thickness with the control of the 
retention time makes it possible to carry out the calcination step and, 
when desirable, the bloating or expanding step on the various particles. 
This, in turn, permits faster and more efficient use of the heat transfer 
to the particles being processed. The agglomeration process also allows 
for the reprocessing of waste materials into useful products. An example 
is perlite fines can be processed into a perlite aggregate, a mixture of 
spent filter aid (either diatomaceous earth or perlite) and unexpanded 
perlite ore can be reprocessed back into a filter aid or can be processed 
to make a light-weight aggregate for use in concrete or a mixture of fly 
ash and unexpanded perlite ore can be processed to produce a light-weight 
aggregate or a filter aid. 
Again, I consider that one of the main advantages of the furnace 28 and 
this method is the ability to achieve a product equal to or superior than 
achieved with a vertical furnace, a stationary horizontal furnace, or a 
rotary furnace with less fuel consumption. The fuel consumption of this 
furnace and method is in the range of about one-half to two-thirds of that 
achieved with one of those enumerated furnaces. In this regard, an article 
by Herbert A. Stein, "MEASURES FOR CONSERVATION OF FUEL IN THE EXPANSION 
OF PERLITE" states: 
"With the high cost of fuel today, it is more important than ever to reduce 
the amount of fuel used in expanding perlite. 
"Perlite expanding processes are often operated at very low fuel 
efficiency, sometimes less than 25%. Some of the reasons for this are as 
follows: 
"1. Present-day expanders are co-current, that is, the perlite and the 
flame enter the expansion chamber together and leave together. This means 
that the hot gases leave the furnace at a higher temperature than the 
expanded perlite. The co-current operation is in contrast to the 
counter-current operation used in cement kilns and boilers, for example, 
where the incoming feed absorbs heat coming from the hot zone. 
"2. Present-day expander tubes are uninsulated and made of metal, to 
operate at a lower temperature in order to avoid fusion and damage to the 
tube. As a result, more heat often passes through the furnace tube wall 
than is needed to expand the perlite. 
"3. Many perlite expanding processes do not involve recovering wasted heat 
by using it to preheat the ore or the combustion air. 
"4. Many furnaces, especially verticals, are operated with too much air 
flow, well in excess of what is needed for combustion. This air must be 
heated to the operating temperature. 
"5. Many furnaces are operated at a production rate which is too low for 
good fuel efficiency per ton, often because the auxilliary equipment (such 
as cyclones, air locks, and cooling and bagging facilities) is too small 
to handle the higher production rate. 
"6. Another cause of high fuel consumption due to too low a production rate 
is the use of an ore which is coarser than necessary for the intended end 
use of the expanded perlite." 
As contrasted with the comments of Herbert A. Stein, I consider that there 
is not a waste of fuel with my furnace and my method. The air introduced 
into my furnace is used for combustion and not for conveying the products 
from the furnace. Therefore, there is less heat energy required as it is 
not necessary to heat extraneous carrier air. Also, the product is at a 
higher temperature, upon leaving the furnace, than the temperature of the 
products of combustion. The production rates of my furnace can be varied 
to accommodate the material to be processed and also with my furnace, used 
in conjunction with the agglomeration process, it is not always necessary 
to use cyclones, air locks, cooling and bagging facilities and the like. I 
question if it be possible to use agglomerated particles in a rotary 
furnace or a vertical furnace or a stationary horizontal furnace. I think 
that with my furnace there is an expansion of materials which can be 
processed to make a useful product. 
In FIGS. 19 and 20 there is a fragmentary view of a furnace 350. Part of 
the furnace 350 is the plenum chamber 352 in the configuration of a torus. 
The plenum chamber 352 has a bottom wall 354, a top wall 356. On the top 
wall 356 there are passageways 358. The top wall 356 can be a grate for 
having the passageway 358. 
There is an inner wall 360 connecting the bottom wall 354 and the top wall 
356. The inner wall 360 is in the configuration of a circle. 
There is an outer wall 362 connecting with the bottom wall 354 and 
connecting with the top wall 358. The outer wall 362 is in the 
configuration of a circle. 
In the bottom wall 354 there is a hole 86 similar to the hole 86 of FIG. 6. 
A pipe 82 connects with the hole 86 as in a manner similar to FIG. 6. The 
pipe 82 is a conduit or a mixture of air and natural gas into the plenum 
chamber 352 defined by the bottom wall 354, the top wall 356 and the walls 
360 and 362. 
There is positioned on the upper surface of the top wall 358 porous 
firebrick 38. There is positioned between the sides of the porous 
firebrick 38 a silicone adhesive 364. The reader is to understand that the 
adhesive 364 can be any suitable adhesive and does not have to be silicone 
adhesive. The adhesive 364 must be able to withstand a fairly high 
temperature. There is positioned on top of the firebrick 38 porous ceramic 
tile 366. 
There is positioned, in a spaced-apart relationship, above the lower 
ceramic tile 366 upper ceramic tile 368. The upper ceramic tile 368 can be 
positioned in a manner such as illustrated in FIGS. 1, 7, 8, and 18. The 
spacing of the upper ceramic tile 368 with respect to the lower ceramic 
tile 366 can vary depending on the material processed in the furnace. In 
certain instances it may be desirable to have the upper ceramic tile 368 
positioned on the lower surface of refractory brick 110. In FIG. 19 the 
refractory brick 110 is in phantom to allow the reader to understand that 
the brick 110 may be used or may not be used. An adhesive 370 joins the 
adjacent refractory brick 310. The upper ceramic tile 368 can be attached 
to the refractory brick 310 by means of a suitable adhesive or other 
suitable means. The adhesive 370 between the refractory brick 110 must be 
able to withstand the moderate degree of heat. The lower ceramic tile 366 
and the upper ceramic tile 368 are insulators. Therefore, the firebrick 38 
and the refractory brick 310 will not reach the temperature of the surface 
of the tiles 368 and the tile 366 reach. 
There is a depending ceramic tile 372 from the outermost edge of the 
ceramic tile 368. An adhesive 374 connects the ceramic tile 368 with the 
depending ceramic tile 372. The adhesive 374 must be able to withstand a 
high temperature. It may be dedirable to use a silicone adhesive or other 
suitable adhesive. 
In some of the ceramic tile 366 I have increased the porosity by drilling 
holes 376 through the ceramic tile 366. The holes are of a small diameter 
ranging from about 1/64th of an inch in diameter to about 1/32nd of an 
inch in diameter. The reader is to realize that the ceramic tile 366 is an 
insulator. Also, the firebrick 38 is an insulator. A mixture of air and a 
natural gas such as propane or butane flows through the pipe 32 and into 
the plenum chamber 352. One would expect that with the burning of the air 
and natural gas on top of the ceramic tile 366 that combustion of the 
mixture of air and natural gas in the plenum chamber would occur. The 
firebrick 38 is a good insulator. The mixture of air and natural gas can 
rise through the firebrick 38 and burn on top of the firebrick 38 and yet 
the temperature of the air and natural gas in the plenum chamber 352 is so 
low that this mixture will not ignite. With the addition of the ceramic 
tile 366 on top of the firebrick 38 the mixture of air and natural gas 
will rise through the passageways 358 and the top wall 356, rise through 
the firebrick 38 and rise through the ceramic tile 366 to burn on top of 
the ceramic tile 366 without combustion occurring in the plenum chamber 
352. 
In FIGS. 21 and 22 there is illustrated a modification of the furnace 350. 
In FIG. 21 there is illustrated a furnace 378 having a plenum chamber 352 
which has been described with respect to FIGS. 19 and 20. There is a 
ceramic trough 380. In FIG. 22 it is seen that the ceramic trough 380, in 
a plan view, is in the general configuration of a trapezoid. There is a 
bottom 382. There is an inner upright curved wall 384. There is an outer 
curved upright wall 386. There are side walls 388 connecting the walls 384 
and 386. In effect, it is seen that the ceramic trough offers a cavity for 
receiving material. There can be positioned in this cavity a bottom layer 
390 of a heat resistant material. In FIG. 21 the bottom layer 390 is 
illustrated by circular members. The bottom layer 390 may be sand, rock, 
alumina, which is aluminum oxide and other inert material which can 
withstand high heat without fusing. There is positioned on top of the 
bottom layer 390 material 392 which is to be heated or calcined. For 
example, there can be positioned on 390 cement which heated and calcined. 
Also, the material 392 can be zeolite, vermiculite, perlite to name a few 
of the other materials which can be heated and calcined. 
The upper ceramic tile 368 can be positioned above the ceramic trough 380. 
Also, there may be used refractory brick 110. The upper ceramic tile 368 
is positioned below the refractory brick 110. 
There may be an upright ceramic board 394 positioned on the outer edge of 
the firebrick 38. The board 394 may connect with the firebrick 38 by means 
of an adhesive 396. 
In operation the mixture of air and natural gas is introduced through pipe 
82 into the plenum chamber 352. Then, this mixture rises upwardly through 
the passageway 358 in the top wall 356 and also passes upwardly through 
the porous firebrick 38. The air and natural gas mixture, while leaving 
the firebrick 38 passes upwardly through the bottom 382 of the porous 
ceramic trough 380. The air and natural gas mixture can then ignite and 
combust in the bottom layer 390 and also can proceed to combust while 
travelling upward through the material 392 be heated and calcined. The 
combustion of the air and natural gas mixture can occur in the ceramic 
trough 380 and also above the ceramic trough 380 and underneath the upper 
ceramic tile 368. 
In FIGS. 19 and 20 the combustion of the air and the gas mixture occurs 
near the upper surface of the lower ceramic tile 366 and above the upper 
surface of said tile. In FIGS. 21 and 22 the combustion can take place in 
the ceramic trough 380 and among the bottom layer 390 and also among the 
material 392 being heated and calcined. As the combustion takes place in 
these conditions, it is possible to say that this is a burning hearth 
furnace. The hearth being the lower ceramic tile 366 and the ceramic 
trough 380. The mixture of air and natural gas burns, to a degree, 
directly above and in close proximity to the upper surface of the lower 
ceramic tile 366 and also directly above and in close proximity to the 
upper surface of the bottom 382 of the ceramic trough 380. 
To remove the material which has been heated from the furnace 350 and also 
from the furnace 378 there can be used a doctor blade as illustrated in 
FIG. 4. In FIG. 4 the doctor blade is 134. Also, there is illustrated a 
doctor blade 134 in FIG. 11. The reader is to understand that the doctor 
blade 134 can be a mechanical doctor blade for removing the heated or 
calcined product from the space between the lower ceramic tile 366 and the 
upper ceramic tile 368 or between the ceramic trough 380 and the upper 
ceramic tile 368 as the plenum chamber 352 rotates. The doctor blade 134 
removes the heated or calcined product. The doctor 134 may be an air 
doctor for blowing or pushing the heated or calcined product off of the 
rotating plenum chamber 352 and the lower ceramic tile 366 or the ceramic 
tile 390 positioned on top of the plenum chamber 352. It is conceivable 
that in addition to an air doctor 134 for blowing the product out of the 
furnace, that in certain instances there may be used an electrostatic 
doctor 134 for repelling the product out of the furnace by means of 
electric charge. 
In FIG. 23 there is a schematic close sheet 400 for heating and calcining a 
raw material. The raw material may be clay. 
There is illustrated a rotary furnace 420 having a plenum chamber 404. The 
mixture of air and natural gas is introduced into the plenum chamber and 
rises upwardly through the firebrick, and if appropriate, the ceramic 
board. The air and natural gas mixture is burned in the rotary furnace 
402. The furnace 402 has a hood 406. 
Material 408 is a material being heated and calcined. 
There is a rotary dryer 410 for, partially, drying the raw material 412 
being introduced into the furnace 402. 
There is a first preheater 414. The raw material upon leaving the rotary 
dryer 410 is introduced in the first preheater 414. The raw material 
absorbs some heat from the furnace 402. The raw material leaves the 
furnace 402 and is introduced into the second preheater 416. In the second 
preheater 416 the raw material is further heated. From the second 
pre-heater 416 the heated raw material moves to a feeder 418 which 
introduces the heated raw material into the furnace 402. 
There is a cooler 420. The hot material leaving the furnace 402 is 
introduced into the cooler 420. A blower 422 blows cold air into the 
cooler 420 to cool the product from the furnace 402. The cool product 430 
can leave the cooler 420. 
Hot air 424 from the cooled cooler 420 flows to the second preheater 416. 
The hot air from the second preheater 416 is identified as air 426 which 
can flow to the rotary dryer 410 or can mix with hot air 428 from the 
furnace 402. The hot air 426 and the hot air 428 enter into the rotary 
dryer 410 to heat and to dry the raw material 412 which may be clay. 
Again, the product 430 can leave the cooler 420. 
In FIG. 24 there is flow sheet illustrating the transformation of raw 
materials 412, such as clay, to the product 430. 
At step 440 the raw material is dried, see reference numeral 410 of FIG. 
23. 
At step 442 the raw material is heated in a first pre-heater, see 414 of 
FIG. 23. 
At step 444 there is a second pre-heat of the dry raw material, see 416 of 
FIG. 23. 
At step 446 the dry raw material is calcined, see 402 of FIG. 23. 
At step 448 the calcined product such as calcined clay is cooled, see 420, 
FIG. 23. 
Cool air or cool gas is introduced at step 448 to cool the hot product. The 
cooled product 430 exits from the cooling step. 
A hot gas 452, such as air, leaves step 448 and is introduced at step 444 
to assist in pre-heating and drying the raw material. 
From the calcination step 446 hot gas 452 exits and is introduced at step 
440 to dry the raw material. 
From the second pre-heat step 444 a hot gas 454 exits and is introduced at 
step 440 to assist in drying the raw material. 
From the step 442 a hot gas 456 exits and is introduced at step 440 to dry 
the raw material. 
From step 440 there exits a hot humid gas 458. The hot humid gas 458 does 
not have the temperature of the hot gas as 452 and 456 entering step 440. 
Nevertheless, the hot gas 458 does pick up moisture from the raw material 
and exits as a hot moist gas. 
In FIG. 25 there is illustrated another calcining process. A raw material 
412 such as clay or cement may be heated and calcined at step 460. There 
is used in the calcining step 460 a mixture of oxygen fuel such as natural 
gas or vaporized diesel fuel to supply the heat energy. There can be 
introduced into the calcining step 460 a gas such as carbon dioxide 464. 
The carbon dioxide 464 assists in infrared radiation so as to assist in 
the elevation of the temperature of the raw material 412 being calcined at 
step 460. After the calcining step has been realized there is produced a 
product 430. The product 430 can be removed from the calcining step 460. 
In FIG. 25 the oxygen in the oxygen and fuel mixture 462 can be made from a 
manufactured air process. The oxygen can be manufactured in an absorbtion 
system using zeolite. This process is referred to as a pressure swing 
absorbtion. Again, the oxygen can be mixed with carbon dioxide. The 
manufactured air is made of about 80% carbon dioxide and 20% oxygen. One 
of the advantages of such a mixture for the combustion of fuels such as 
natural gas and vaporized diesel is that carbon dioxide absorbs and 
radiates infrared energy. Nitrogen does not absorb and radiate infrared 
energy. Carbon dioxide and water vapor can radiate infrared energy. The 
absorbtion and radiation of the infrared energy by carbon dioxide assists 
in the calcining step 460 or the raw material 412. With the absorbtion and 
radiation of infrared energy by the carbon dioxide the efficiency of the 
calcining step 460 is increased considerably. 
It is to be understood that my invention and apparatus can be used for 
calcining, sintering, roasting, expanding, exfoliating and drying a raw 
material. I consider that my invention and apparatus has some novel 
features such as the hearth and the burner are the same part as previously 
explained. The roof on my furnace, the reflector, is very close to the 
hearth-burner combination. In many instances, the distance between the 
reflector and the hearth-burner of my invention is less than one inch. The 
heat of combustion of the fuel elevates the temperature of the reflector. 
The reflector reflects a considerable amount of infrared energy to the raw 
material being processed. The distance between the reflector and the 
hearth-burner is adjustable so that the raw material, initially, is spaced 
closely to the reflector. If the raw material expands then the distance 
the reflector is from the hearth-burner is increased and the distance 
between the raw material being processed and the reflector can remain 
somewhat constant even though the raw material has expanded. As previously 
shown the reflector can be made into a spiral. 
The hearth-burner, which is porous, allows an air-gas mixture to pass 
through it. The air-gas mixture is ignited substantially at the surface of 
the hearth-burner. The air-gas mixture is distributed evenly across the 
area of the hearth-burner. 
If calcium carbonate is calcined it may be desirable to introduce a gas 
which has a high percentage of oxygen. As previously explained, a 
manufactured air made of 80% carbon dioxide and 20% oxygen is of value 
from the infrared radiation of the carbon dioxide. With the calcining of 
limestone carbon dioxide is liberated and can mix with a gas which is, 
essentially, oxygen or has a high percentage content of oxygen. With the 
release of carbon dioxide from the calcium carbonate there results a 
product known as calcium oxide. 
In FIG. 20 there is illustrated ceramic tile or ceramic board 366 have a 
number of holes 376 drilled into the board. A board which can be used in 
such a manner is identified as K-3000 Board of Babcock and Wilcox. 
With the ceramic trough 380 firebrick 38 can be Babcock and Wilcox K-28. 
Then, Delta's T-Board can be used as a material for the ceramic trough 
380. The Delta T-Board has a better emissivity than the firebrick 380 and 
therefore should assist in heating and calcining the raw material. 
In certain instances the bottom layer 390 in the trough 380 may exceed the 
temperature the ceramic trough 380 can function. In instances like this, 
Babcock and Wilcox K-28 firebrick will be used as base brick 38. There is 
laid in the ceramic tile 380 a layer of Babcock and Wilcox kaowool 
blanket. Then, the loose material 390 such as sand, rock, alumina or other 
suitable material is laid on top of the kaowool blanket. The result of 
this is that a higher temperature can be realized and a greater emissivity 
can realized to assist in the heating and calcining step. 
The firebrick 38 can be selected from many commercial manufactures. I am 
using a K-28 Babcock and Wilcox firebrick because this firebrick has an 
extra high air permeability and will stand an operating temperature up to 
2,800.degree. F. The extra high air permeability of brick allows the 
mixture of air and propane to pass upwardly through the brick. 
From experience I have learned that the weight of the firebrick 38 is a 
direct indication of its air permeability. Therefore, the firebrick 38 
must be selected so that all of the bricks have nearly the same weight so 
as to have near the same equal air permeability. A heavy brick mixed with 
a light brick will have less temperature as compared to the light brick. A 
Babcock and Wilcox K-28 brick having dimensions of 21/2 inches times 41/2 
inches times 9 inches weighs about three pounds. From experience I tried 
to maintain the weight of all the bricks within plus or minus one ounce of 
the average weight of the bricks. By maintaining a close tolerance on the 
weight of the bricks for equal sized bricks, there is a close tolerance on 
the air permeability of the bricks and movement of the mixture of air and 
natural gas upwardly through the brick. 
The support I use for the firebrick 38 and the ceramic tile 366 and the 
ceramic tile 380 is a flat expanded metal. The bricks are glued to the 
expanded steel metal and to each other at the bottom edges and to the 
steel parts that make the inner and outer steel circle. The glue I use is 
silicone caulking No. 108 of General Electric Company. The silicone rubber 
caulking allows some movement of the brick without rupturing the seal. 
The firebrick 38 overlies the top wall 356 or the expanded steel metal. 
Also, the ceramic tile or ceramic board or ceramic trough is of less width 
than the firebrick 38. As illustrated in FIG. 19 and also in FIG. 21 there 
is ceramic wall above the upper surface of the firebrick 38 but almost to 
the outer edge of the firebrick 38 to reflect heat energy back to the raw 
material, to preclude cold air entering the furnace, to preclude the 
product from escaping form the furnace, and to assist in the construction 
of the furnace for maintaining the product at a proper place. 
The top surface of the firebrick 38 that is not under the reflector is 
sealed with paint or cement to prevent the air-gas mixture from coming 
through the firebrick at that particular place. The paint or cement can be 
considered to be a valve for controlling the flow of air and natural gas 
mixture to the hearth-burner. 
The doctor 134 can be air pressure for removing the product from the 
furnace or can be a vacuum for lifting the product off of the ceramic tile 
or off of the ceramic trough. 
From experience, and to date, I have found that the most efficient 
combination of components is a firebrick identified as Babcock and Wilcox 
K-28 base brick. Then, a Delta T insulation board of ceramic construction 
is useful for the lower ceramic tile 366 of the ceramic trough 380. For 
the upper ceramic tile 368 I use a Johns Manville "Cerachrome 130" ceramic 
board as a reflector. In the tests I have run the K-28 brick by itself 
takes about 38% more fuel to hold the same temperature as when Delta T 
insulation board is laminated over the K-28 brick. I consider that this 
demonstrates that the surface emissivity is a vital key to fuel efficiency 
in the furnace. The surface emissivity of the ceramic board or Delta T 
insulation board is greater than the surface emissivity of the K-28 brick. 
Therefore, with greater emissivity a higher temperature can be realized 
with the same amount of fuel or if a set temperature is to be realized 
less fuel is required to realize that set temperature. 
It is possible to use a number of different materials for the firebrick and 
also for the ceramic tile or ceramic trough. A ceramic board or a ceramic 
tile can be made sensibly from kaolin clay fibers, called kaowool. The 
ceramic board from kaowool is fairly soft but is stable to a temperature 
of about 3000.degree. F. Also, the ceramic board is permeable allowing a 
mixture of air and natural gas to pass through the ceramic board. 
The Delta T board is quiet soft but hardens when exposed to heat. Delta T 
board is stable and has good permeability to temperatures of at least 
1,850.degree. F. 
A foam can be made from silicone carbide. Such a foam may be useful as a 
tile or as a trough and has good permeability. 
A honeycomb can be made from silicone carbide, lithium, alumino silicate, 
magnesium aluminom silicate and the like. The honeycomb should have small 
holes or small passageways to allow the mixture of air and natural gas or 
air and fuel to pass through the honeycomb. 
For the bottom layer 390 in the trough 380 a loose fill such as particles 
of silicone carbide and alumina coated with kaowool dust or chromium 
oxide, to improve emissivity can be used. In certain instances a material 
has good emissivity such as clay and sand. 
The size of the furance can vary depending upon the need. I have 
established some parameters for the size of the furnace. It think that an 
energy of 50,000 BTU's (British Thermal Units) per hour per square foot of 
the ceramic tile or board 366 or the firebrick 38 is a good average 
number. Also, I think that a limit of the width of the burner deck or the 
ceramic tile 366 or the firebrick 38 should be not more than four feet. It 
is possible to have the width of the burners at any reasonable width but 
because of problems of feeding the raw material to the burner deck and the 
discharge of the product a practical working width of four feet would be 
desirable. 
An example of a furnace can be a furnace with an outer diameter of twenty 
four feet and a deck width of four feet. It has a burner surface of 
approximately 250 square feet. At a heat energy of 50,000 BTU's per square 
foot per hour this means that the furnace has a capacity of approximately 
12,500,000 BTU's per hour. The size of the furnace can be determined with 
respect to the raw material and the product. 
The steel used for the top wall 356 and also for the supporting of 
firebrick can be of standard mild steel. The top wall 356 can be expanded 
metal approximately 11/2 inch #9F-10 guage mild steel. It can be secured 
from McNichols Company, 10877 Rockwallet, Dallas Tex. This type of steel 
can be found in most steel supply yards. 
The base firebrick 38 can be an insulating firebrick having a dimension of 
about 21/2 inches times 41/2 inches by 9 inches and type K-28. It can be 
secured from Babcock and Wilcox, Refractory Division, Old Savannah Road, 
Augusta, Ga. The ceramic tile 366 can be a Delta T insulation board from 
Keene Corp., Insulation Operation, 1603 Fulford Street, Kalamazoo, Mich. 
The upper ceramic tile 368 which is used for reflection can be Cerachrome 
130 Insulation Board, Johns Manville, Ken-Caryl Ranch, Denver, Colo. 
In FIG. 23 the raw material 412 can be clay. The clay is calcined to the 
product 430 and can be used as a light based aggregate and also can be 
used for kitty litter. 
Again, the combustion of the fuel and air takes place substantially at the 
surface of the firebrick 38 or the surface of the ceramic tile 366 so that 
the burning of the air and fuel occurs at the hearth of the furnace. 
As is recalled, a main advantage of this invention and this furnace is that 
less fuel is required to realize the desired temperature inside of the 
furnace. With this furnace, less air is required. Air comprises 
approximately 80% nitrogen and 20% oxygen. If less air is required for 
heating purposes then it is not necessary to heat the nitrogen. If it is 
not necessary to heat the nitrogen then less fuel is required. With many 
furnaces a large amount of air is introduced to remove the product. 
Another advantage of this furnace is that with the use of ceramic board 
and ceramic fibers there is better emissivity from the ceramic board and 
fibers than with firebrick. Because of the better emissivity from the 
ceramic board and fibers as compared with firebrick less fuel is required 
to realize the desired temperature in the furnace. In addition to this if 
a mixture of gas comprising carbon dioxide and oxygen is used, there is 
better emissivity of this gas than with air and fuel. For example, if a 
gas comprising 80% carbon dioxide and 20% oxygen is mixed with natural gas 
or vapor diesel fuel, a better emissivity is realized than if air and 
natural gas and air and vaporized diesel fuel is used. With better 
emissivity then less fuel is required to realize the desired temperature 
in the furnace. Carbon dioxide has better emissivity characteristics with 
respect to infrared radiation than nitrogen. The emissivity 
characteristics of nitrogen and infrared radiation are poor while the 
emissivity characteristics of carbon dioxide and infrared radiation are 
good. A combination of these factors indicates that less fuel is required 
to realize the desired temperature in the furnace than with a vertical 
furnace, a rotary furnace or a horizontal stationary furnace. With the 
increasing cost in the price of natural gas and also the increase in cost 
in the price of diesel fuel, it is desirable to use as small a quantity of 
fuel as possible to lessen the cost of processing the raw material to the 
desired product and realizing the desired temperature in the furnace. 
With the furnace 350 it is also possible to introduce the material, viz., 
perlite, vermiculite, volcanic ash, pumice and zeolite, as introduced into 
the furnace 28. In addition to expanding or bloating materials, such as 
perlite and vermiculite, as in the furnace 28, the furnace 350 can also be 
used for calcining materials. For example, materials 220 which can be 
calcined or diatomaceous earth, clay, cement, titanium dioxide, fly ash, 
volcanic ash, natural zeolites, and pumice, to name a few. In addition, 
radioactive material can be treated and processed in the furnace 350 in a 
manner similar to that in which the radioactive material can be treated 
and processed in furnace 28. There can be introduced into the furnace 350 
a solid material comprising the material to be treated or calcined along 
with fuel such as diesel oil or powdered coal. The aggregate of the 
material to be treated plus the diesel oil or the aggregate of the 
material to be treated plus the powdered coal can be introduced onto the 
ceramic tile or ceramic board 366 or onto the trough 380. 
The furnace 350 can be used for the same operations as the furnace 28 in 
FIGS. 1-11 and FIGS. 16-18. The furnace 350 is more fuel efficient or more 
energy efficient than the furnace 28. The furnace 350 has better 
emissivity characteristics as there is used the ceramic board or ceramic 
mat or the trough 380 or for the lower second heating material 366 and the 
third upper heating material 368. In addition, the fuel introduced into 
the furnace 350 can also be introduced into the mixture comprising carbon 
dioxide and oxygen. Instead of introducing the fuel with a mixture of air 
comprising nitrogen and oxygen, the fuel can be introduced with a gaseous 
mixture comprising carbon dioxide and oxygen. The carbon dioxide has 
better emissivity characteristics than the nitrogen and therefore, less 
fuel is required to realize the desired temperature with the carbon 
dioxide in the atmosphere in place of the nitrogen. The carbon dioxide has 
desirable emissivity characteristics in that it reflects infrared light 
waves and gives off infrared radiation while nitrogen does not have these 
characteristics. 
I consider my invention to be new, useful, and unobvious. 
35 USC 101 states: 
"Whosever invents or discovers any new and useful process, machine, 
manufacture, or composition of matter, or any new and useful improvement 
thereof, may obtain a patent therefor, subject to the conditions and 
requirement of this title." 
I consider my invention to be new as I do not know of another furnace or 
another method for processing a material to make an expanded product or a 
calcined product. I do not know of another furnace having upper and lower 
bricks and wherein a material to be processed can be placed in rotating 
firebricks for being heat processed and also wherein the air introduced 
into the furnace and the air used in my method is, essentially, the air 
for combustion purposes and not for carrier purposes. 
I consider my invention to be useful as it can be used to expand or bloat 
material such as vermiculite, perlite, volcanic ash, and pumice. Also, my 
furnace and my method can be used for calcining materials such as 
diatomaceous earth, clay, titanium dioxide, cement, fly ash, volcanic ash, 
zeolite, perlite, vermiculite, pumice, and the like. These products can be 
used for horticultural purposes fly ash, storing of radioactive wastes in 
a solid matrix, for lightweight concrete, and the like. 
35 USC 103 states: 
"A patent may not be obtained though the invention is not identically 
disclosed or described as set forth in section 102 of this title, if the 
differences between the subject matter sought to be patented and the prior 
art are such that the subject matter as a whole would have been obvious at 
the time the invention was made to a person having ordinary skill in the 
art to which said subject matter pertains. Patentability shall not be 
negatived by the manner in which the invention was made." 
I consider my invention to be unobvious as, again, I have not seen or heard 
of another furnace or method similar to my furnace and method. 
In preparing this patent application, a patent search was not made but 
information I know in regard to a rotary furnace, a vertical furnace, a 
stationary horizontal furnace for processing perlite and vermiculite has 
been disclosed. Also, there has been called to my attention three U.S. 
Pat. Nos. 2,659,521; 2,672,483; and, 2,572,484.