ASTM E953-88(2004)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:E953–88(Reapproved 2004)
Standard Test Method for
Fusibility of Refuse-Derived Fuel (RDF) Ash
This standard is issued under the fixed designation E 953; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope Shrinking or warping of the cone is ignored if the tip remains
sharp. In Fig. 1, the first cone shown is an unheated one; the
1.1 This test method covers the observation of the tempera-
second cone, IT, is a typical cone at the initial deformation
tures at which triangular pyramids (cones) prepared from RDF
stage.
ash attain and pass through certain stages of fusing and flow
3.3 softening temperature, ST—the temperature at which
when heated at a specific rate in controlled, mildly-reducing,
the cone has fused down to a spherical lump in which the
and oxidizing atmospheres.
height is equal to the width at the base as shown by the third
1.2 The test method is empirical, and strict observance of
cone, ST, in Fig. 1.
the requirements and conditions is necessary to obtain repro-
3.4 hemispherical temperature, HT—the temperature at
ducible temperatures and enable different laboratories to obtain
which the cone has fused down to a hemispherical lump at
concordant results.
which point the height is one half the width of the base as
1.3 The values stated in SI units are to be regarded as the
shown by the fourth cone, HT, in Fig. 1.
standard. The values given in parentheses are for information
3.5 fluid temperature, FT—the temperature at which the
only.
fused mass has spread out in a nearly flat layer with a
1.4 This standard does not purport to address all of the
maximum height of 1.6 mm ( ⁄16 in.) as shown in the fifth
safety problems, if any, associated with its use. It is the
cone, FT, in Fig. 1.
responsibility of the user of this standard to establish appro-
3.6 forms of refuse-derived fuel (RDF):
priate safety and health practices and determine the applica-
RDF-1—Waste used as a fuel in as-discarded form.
bility of regulatory limitations prior to use. See Section 6 for
RDF-2—Waste processed to coarse particle size with or
additional hazard information.
without ferrous metal separation.
2. Referenced Documents
RDF-3—Shredded fuel derived from municipal solid waste
(MSN) that has been processed to remove metal, glass, and
2.1 ASTM Standards:
other inorganics. This material has a particle size such that 95
E 180 Practice for Determining the Precision Data of
weight % passes through a 2-in. square mesh screen.
ASTM Methods for Analysis and Testing of Industrial
RDF-4—Combustiblewasteprocessedintopowderform,95
Chemicals
weight % passing a 10-mesh screening.
E 829 Practice for Preparing Refuse-Derived Fuel (RDF)
RDF-5—Combustible waste densified (compressed) into the
Laboratory Samples for Analysis
form of pellets, slugs, cubettes, or briquettes.
3. Terminology
RDF-6—Combustible waste processed into liquid fuel.
RDF-7—Combustible waste processed into gaseous fuel.
3.1 Definitions and Symbols:
3.1.1 The critical temperature points to be observed are as
4. Significance and Use
follows, denoting the atmosphere used:
4.1 The standard is available to producers and users of RDF
3.2 initial deformation temperature, IT—the temperature at
to use in determining the fusibility of ash produced from RDF.
which the first rounding of the apex of the cone occurs.
4.2 Limitations of Ash Fusibility Data—Ash fusibility data
are too often over-interpreted. In practice, types of burning
This test method is under the jurisdiction of ASTM Committee D34 on Waste
equipment, rate of burning, temperature and thickness of fire
Management and is the direct responsibility of Subcommittee D34.03.02 on
bed or ball, distribution of ash forming mineral matter in the
Municipal Recovery and Reuse.
RDF, and viscosity of the molten ash may influence ash
Current edition approved April 1, 2004. Published May 2004. Originally
approved in 1983. Last previous edition approved in 1998 as E 953 – 88 (1998).
behaviormorethantheashfusibilitycharacteristicsdetermined
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
by the laboratory test. Furthermore, conditions existing during
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
applied combustion of RDF are so complex that they are
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. impossible to duplicate completely in a small-scale laboratory
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E953–88 (2004)
FIG. 1 Critical Temperature Points
test. Therefore, the test should be considered an empirical one
and the data, at best, only qualitative.
5. Apparatus
5.1 Furnace—Any gas-fired or electric furnace conforming
to the following requirements may be used.
5.1.1 The furnace shall be capable of maintaining a uniform
U.S. Customary Units. SI Units,
temperature zone in which to heat the ash cones. This zone
in. mm
shall be such that the difference in the melting point of 12.7
⁄4 6.4
mm ( ⁄2 in.) pieces of pure gold wire when mounted in place of
⁄4 19.1
the ash cones on the cone support shall be not greater than 1 ⁄2 38.1
2 50.2
11°C (20°F) in a reducing atmosphere test run.
3 76.2
5.1.2 The furnace shall be capable of maintaining the
FIG. 2 Brass Cone Mold
desired atmosphere surrounding the cones during heating. The
composition of the atmosphere, reducing or oxidizing, shall be
maintained within the limits specified in Section 7.The desired
National Bureau of Standards, or checked periodically against equipment
atmosphere in the gas-fired furnace surrounding the cones shall
certified by the National Bureau of Standards.
be obtained by regulation of the ratio of gas to air in the
combustion mixture. The desired atmosphere in the electric
5.3.2 Thermocouple—A thermocouple of platinum and
furnaceshallbeobtainedbymeansofgasesintroducedintothe
platinum-rhodium, protected from the furnace gases by a
heatingchamber.Themuffleshallbegas-impervious,freefrom
glazed porcelain sheath, shall be used with a high-resistance
cracks, and the closure-plug tight fitting. Since state-of-the-art
millivoltmeterorpotentiometeraccurateandreadabletowithin
furnaces vary somewhat in design, the gas supply inlet tube
5.5°C (10°F). The sheath shall be sealed to the furnace wall by
shall be installed per instructions of furnace manufacturer.
alundum cement. The hot junction of the thermocouple shall
5.1.3 The furnace shall be capable of regulation so that the
touch the end of the sheath and shall be located in the center of
rate of temperature rise shall be 8 6 3°C (15 6 5°F) per
the muffle and immediately to the rear of the cones. The
minute.
thermocouple protective sheath shall be checked periodically
5.1.4 The furnace shall provide a means of observing the
for cracks. The thermocouple and its meter shall meet the
ash cones during the heating. Observation shall be on the same
requirements of Section 10. The potentiometer or millivoltme-
horizontal plane as the cone-support surface.
ter shall be located or shielded adequately as to prevent radiant
5.2 Cone Mold—A commercially available cone mold as
or convection heating of the cold junction. The room tempera-
shown in Fig. 2 shall be used.The cone shall be 19 mm ( ⁄4 in.)
ture compensator shall be adjusted to the existing temperature.
in height and 6.4 mm ( ⁄4 in.) in width at each side of the base
5.4 Ash-Cone Refractory Support—The ash cone shall be
which is an equilateral triangle.
mounted on a refractory base composed of a mixture of equal
5.2.1 Asteel spatula with a pointed tip, ground off to fit the
parts by weight of kaolin and alumina conforming to the
cone depression in the mold, is suitable for removal of the ash
following requirements:
cone.
5.4.1 Kaolin—NF-Grade powder passing a No. 200 (0.074
5.3 Optical Pyrometer or Thermocouple, for temperature
mm) sieve.
measurements, conforming to the following requirements:
5.4.2 Aluminum Oxide—Reagent grade powder passing a
5.3.1 Optical Pyrometer—An optical pyrometer of the dis-
No. 100 (0.149 mm) sieve.
appearing filament type shall be used. The instrument shall
5.5 Refractory Support Mold—A mold with flat top and
have been calibrated to be accurate within 11°C (20°F) up to
bottom surfaces to provide a refractory support of suitable
1400°C(2550°F)andwithin16°C(30°F)from1400to1600°C
thickness to minimize warping shall be used. A side mold not
(2550°F to 2900°F) (Note 1). The pyrometer filament shall be
over ⁄4 in. (6.4 mm) high of any convenient shape, placed on
sighted on the cones until the softening point temperature (Fig.
an iron plate so that the top surface of the refractory mix can
1) has been passed, and then sighted on the cone support. The
be struck off flat and parallel to the base by means of a
pyrometer shall have readable graduations not larger than
straightedge, is satisfactory. For electric furnace use, legs not
5.5°C (10°F). 1
over3mm( ⁄8 in.) long may be provided on the corners of the
cone support by suitable holes bored in the iron base plate of
NOTE 1—The pyrometer equipment shall be standardized periodically
by a suitably equipped standardizing laboratory such as that of the the mold.
E953–88 (2004)
3 6
5.6 Gold Wire, Twenty-four gage or larger round wire of 5volume %carbondioxide, shallbemaintainedintheheating
99.98 % purity, but drawn from metal of 99.99 % purity, and chamber throughout the test (Note 2) in the electric furnace.
having a melting point of 1063°C (1945°F). The gas stream shall be regulated by any convenient means to
5.7 Nickel Wire, Twenty-four gage or larger round wire of provide a measured flow of 1.3 to 1.5 furnace volumes per
CP nickel 99.98 % pure, fully annealed, and having a melting minute.
point of 1452°C (2645°F).
NOTE 2—New cylinders of the mixed gas for which a certified analysis
is not available should be mixed before use by laying the cylinder on its
6. Hazards
side with the protective screw cap in place. The cylinder should then be
6.1 Due to the origins of RDF in municipal waste, common rolled back and forth, 6 to 10 ft in each direction, approximately 15 times.
Certified analyses of each cylinder or batch can be obtained for a small
sense dictates that some precautions should be observed when
extra charge.
conducting tests on the samples. Recommended hygenic prac-
tices include use of gloves when handling RDF; wearing dust 7.2.2 Oxidizing Atmosphere Test—Aregulated stream of air
masks (NIOSH-approved type); especially while milling RDF shall be maintained throughout the test in the electric furnace.
samples; conducting tests under a negative pressure hood when The gas stream shall be regulated by any convenient means to
possible; and washing hands before eating or smoking. provide a measured flow of 1.3 to 1.5 furnace volumes per
minute.
6.2 Good laboratory practices dictate the precautions that
should be observed when using compressed gases such as
8. Preparation of Ash
hydrogen or carbon monoxide as reducing gases.
8.1 Use RDF milled to passing a 0.5-mm (0.02-in.) sieve
7. Test Atmosphere
preparedinaccordancewithPracticeE 829toobtaintheashby
7.1 Gas Fired Furnace:
incinerationinawell-ventilatedmufflefurnace.Thequantityof
7.1.1 Reducing Atmosphere Test—A mildly reducing atmo- RDF required will vary with the ash content; usually 3 to 5 g
sphere surrounding the cones shall be maintained during the
of ash will suffice for cones for several check determinations.
test in the gas-fired furnace. Hydrogen, hydrocarbons, and Spread out the analysis sample of RDF in a layer approxi-
carbon monoxide shall be considered as reducing gases;
mately 6.4 mm ( ⁄4 in.) in depth in a fireclay or porcelain
oxygen,carbondioxide,andwatervaporshallbeconsideredas roasting dish. Place the dish in the muffle at a low temperature,
oxidizing gases. Nitrogen is inert. The ratio by volume of
and gradually heat to redness at such a rate as to avoid
reducing gases to oxidizing gases in the atmosphere shall be mechanical loss from too rapid expulsion of volatile matter.
between the limits of 20 to 80 %, that is, on a nitrogen-free
The rate of temperature rise of 500°C (932°F) in 1 h was found
basis, the total amount of reducing gases present shall be
to be satisfactory. Complete the conversion to ash at a
between the limits of 20 and 80 volume %.Aflame 150 to 200
temperatureof800to900°C(1470to1650°F).Transfertheash
mm (6 to 8 in.) in height and tinged with yellow above the
to an agate mortar (Note 3), and grind so it will pass a No. 200
furnace outlet has been found to provide an atmosphere within
(0.074 mm) sieve.
the specified limits.
NOTE 3—Amechanicalagatemortargrinderwillsavetimewheremany
7.1.2 Oxidizing Atmosphere Test—An atmosphere contain-
determinations are made. An iron mortar or pestle is not recommended
ing a minimum amount of reducing gases shall be maintained
because of metallic contamination.
surrounding the cones during the test in the gas-fired furnace.
8.2 Spread the ash in a thin layer in a fireclay, silica, or
On a nitrogen-free basis, the volume of the reducing gases
porcelain dish and ignite it in a stream of oxygen for 1 ⁄2hat
present in the atmosphere will not exceed 10 volume %.
800to850°C(1470to1560°F)toensurecompleteanduniform
Combustion with the maximum possible quantity of air with
oxidation of the ash. Any tube or muffle-type furnace which,
preservation of the specified rate of temperature increase has
whensuppliedwithanoxygenflowofnotlessthanonefurnace
been found to provide an atmosphere within the specified
volume in 5 min will maintain a highly oxidizing atmosphere,
limits. A completely blue flame, not over 50 mm (2 in.) in
is suitable.
heightabovetheoutletatthebeginningofthetest,providesthe
NOTE 4—It has been found that in most samples, the initial ignition
desired atmosphere; and, by regulation of the combustion
outlined in 8.1 is sufficient to convert the RDF to ash and the reignition
gas-air ratio, the specified atmosphere and temperature rise can
step in 8.2 is not necessary. Reignition of the ash should be made only if
be maintained.
an observable amount of noncombustible matter or carbon is present.
7.2 Electric Furnace:
7.2.1 Reducing Atmosphere Test—A regulated flow of gas
9. Preparation of Cones
of the nominal composition, 60 % carbon monoxide and 40 6
9.1 Thoroughly mix the ignited ash in a mechanical mixer
or on a sheet of glazed paper or oil cloth by raising first one
corner to roll the a
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