ASTM E1755-95

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Designation: E 1755 – 95
Standard Test Method for
Ash in Biomass
This standard is issued under the fixed designation E 1755; 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 5. Apparatus
1.1 This test method covers the determination of ash, 5.1 Aluminum Weighing Pans or Crucibles, 50 mL,if
expressed as the mass percent of residue remaining after dry crucibles are used, platinum crucibles are preferred, but silica
oxidation (oxidation at 575 6 25°C), of hard and soft woods, or porcelain crucibles may be used.
herbaceous materials (such as switchgrass and sericea), agri- 5.2 Muffle Furnace, an electric furnace is recommended for
cultural residues (such as corn stover, wheat straw, and igniting the sample. The furnace should be fitted with an
bagasse), wastepaper (such as office waste, boxboard, and indicating pyrometer or thermocouple, so that the required
newsprint), acid and alkaline pretreated biomass, and the solid temperature of 575 6 25°C can be maintained.
fraction of fermentation residues. All results are reported 5.3 Analytical Balance, sensitive to 0.1 mg.
relative to the 105°C oven-dried mass of the sample. For 5.4 Desiccator, using anhydrous calcium sulfate.
particulate wood fuels, Test Method E 1534 should be used. 5.5 Drying Oven, with temperature control of 105 6 2°C.
1.2 The values stated in SI units are to be regarded as the
6. Test Specimen
standard.
1.3 This standard does not purport to address all of the 6.1 Test specimens suitable for analysis by this test method
are as follows:
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 6.1.1 Prepared biomass samples that have been prepped
according to Practice E 1757.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. 6.1.2 Biomass feedstocks, dried at 105°C according to Test
Method E 1756,
2. Referenced Documents
6.1.3 Pretreated biomass, dried at 105°C according to Test
2.1 ASTM Standards: Method E 1756, and
E 1534 Test Method for Determination of Ash Content of 6.1.4 The solids fraction of fermentation residues, dried at
Particulate Wood Fuels 105°C according to Test Method E 1756.
E 1756 Test Method for the Determination of Total Solids in 6.2 The test specimen shall consist of approximately 0.5 to
Biomass 1.0 g of sample obtained in such a manner to ensure that it is
E 1757 Practice for Preparation of Biomass for Composi- representative of the entire lot of material being tested. For
tional Analysis 105°C dried samples containing large particles or chunks, it is
recommended that the sample be ground or milled to reduce
3. Terminology
the size of the large pieces to less than 1 mm in diameter. The
3.1 Descriptions of Terms Specific to This Standard: sample is then redried at 105°C prior to testing. Prepared
3.1.1 ash—the inorganic residue left after ignition at 5756
biomass can be used in place of 105°C dried material, but the
25°C. mass of the material must be corrected for its moisture content
by using Test Method E 1756, prior to calculating the ash.
4. Significance and Use
7. Procedure
4.1 The ash content is an approximate measure of the
mineral content and other inorganic matter in biomass.
7.1 Mark a pan or crucible with a unique identification using
4.2 The ash content is used in conjunction with other assays a porcelain marker, place it in the muffle furnace, and bring to
to determine the total composition of biomass samples.
constant mass by igniting at 575 6 25°C. Remove the pan or
crucible from the furnace, cool to room temperature in a
desiccator, and weigh to the nearest 0.1 mg. Record this mass
as the tare mass, m . Keep the pan or crucible in a desiccator
This test method is under the jurisdiction of ASTM Committee E-48 on cont
Biotechnology and is the direct responsibility of Subcommittee E48.05 on Biomass
until used.
Conversion.
NOTE 1—For an aluminum pan, two hours of heating at 575 6 25°C
Current edition approved Oct. 10, 1995. Published December 1995.
Annual Book of ASTM Standards, Vol 11.05. will be sufficient to bring the pan to constant mass. With a crucible,
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
E 1755
however, the following procedure is used: place the crucible in the furnace
where:
at 5756 25°C for 3 h. Remove the crucible and place in a desiccator.
m 5 mass of moisture-free solids in the prepared bio-
s
Allow the crucible to cool to room temperature and then weigh the
mass sample, g,
crucible to the nearest 0.1 mg. Record this mass. After weighing, return
m 5 initial mass of prepared biomass sample and
ar
the crucible to the furnace for1hat575 6 25°C, cool again in the
container, g,
desiccator, and reweigh. Repeat this step until the mass of the crucible
m 5 tare mass of container, g, and
varies by less than 0.3 mg from the previous weighing. Record this final
cont
T 5 mass percent of total solids in sample, as deter-
mass as the crucible tare mass, m .
cont
mined by Test Method E 1756.
7.2 Weigh approximately 0.5 to 1.0 g, to the nearest 0.1 mg,
% ash 5 @~m 2 m !/m # 3 100 (3)
ash cont s
of a test specimen into the tared pan or crucible. If the sample
being analyzed is a test specimen dried at 105°C, the sample
where:
should be stored in a desiccator until use. For a 105°C dried
% ash 5 mass percent of ash, based on 105°C oven-dried
test sample, record the mass (container plus sample mass) as
mass of the sample,
the initial mass, m . For prepared biomass samples prepped
od m 5 mass of ash and container, g,
ash
according to Practice E 1757, record the mass (container plus
m 5 tare mass of container, g, and
cont
sample mass) as the initial mass, m . m 5 mass of moisture-free solids in the prepared
ar
s
biomass sample, g.
NOTE 2—For prepared biomass samples, it is recommend that samples
for moisture determination should be weighed out at the same time as the
9. Report
samples for the ash determination. If this is done at a later time it can
9.1 Report the result to two decimal places, as a mass
introduce an error in the calculation because ground biomass can rapidly
percent of the sample’s 105°C dried mass, and cite the basis
gain or lose moisture when exposed to the atmosphere.
used in the calculation.
7.3 Place the container and contents in the muffle furnace
and ignite at 575 6 25°C for a minimum of 3 h, or until all the 10. Precision and Bias
carbon is eliminated. To avoid flaming, initially heat
...