Standard Test Method for Laboratory Weathering of Solid Materials Using a Humidity Cell

SIGNIFICANCE AND USE
The laboratory weathering procedure will generate data that can be used to: (1) determine whether a solid material will produce an acidic, alkaline, or neutral effluent, (2) identify solutes in the effluent that represent dissolved weathering products formed during a specified period of time, (3) determine the mass of solute release, and (4) determine the rate at which solutes are released (from the solids into the effluent) under the closely controlled conditions of the test.
Data generated by the laboratory weathering procedure can be used to address the following objectives: (1) determine the variation of drainage quality as a function of compositional variations (for example, iron sulfide and calcium+magnesium carbonate contents) within individual mine-rock lithologies, (2) determine the amount of NP accessible in a mine-rock sample to neutralize acid and maintain drainage pH≥6.0 under the conditions of the test, (3) estimate mine-rock weathering rates to aid in predicting the environmental behavior of mine rock, and (4) determine mine-rock weathering rates to aid in experimental design of site-specific kinetic tests.
The laboratory-weathering procedure provides conditions conducive to oxidation of solid material constituents and enhances the transport of weathering reaction products contained in the resulting weekly effluent. This is accomplished by controlling the exposure of the solid material sample to such environmental parameters as reaction environment temperature and application rate of water and oxygen.
Because efficient removal of reaction products is vital to track mineral dissolution rates during the procedure, laboratory leach volumes are large per unit mass of rock to promote the rinsing of weathering-reaction products from the mine-rock sample. A comparison of laboratory kinetic tests with field tests has shown that more reaction products from mineral dissolution are consistently released per unit weight and unit time in laboratory weatherin...
SCOPE
1.1 This kinetic test method covers a laboratory weathering procedure that (1) enhances reaction-product transport in the aqueous leach of a solid material sample of specified mass, and (2) measures rates of weathering-product mass release. Soluble weathering products are mobilized by a fixed-volume aqueous leach that is performed and collected weekly. Leachate samples are analyzed for pH, alkalinity/acidity, specific conductance, sulfate, and other selected analytes.
1.1.1 This test method is intended for use to meet kinetic testing regulatory requirements for mining waste rock and ores sized to pass a 6.3-mm (0.25-in.) Tyler screen.
1.1.2 Interlaboratory testing of this method has been confined to mine waste rock. Application of this test method to metallurgical-processing waste (for example, mill tailings) is outside the scope of the test method.
1.2 This test method is a modification of a laboratory weathering procedure developed originally for mining wastes (1-3). However, it may have useful application wherever gaseous oxidation coupled with aqueous leaching are important mechanisms for contaminant mobility.
1.3 This test method calls for the weekly leaching of a well-characterized solid material sample (weighing at least 1000-g), with water of specified purity, and the collection and chemical characterization of the resulting leachate. Test duration is determined by the user’s objectives of the test.
1.4 As described, this test method may not be suitable for some materials containing plastics, polymers, or refined metals. These materials may be resistant to traditional particle size reduction methods.
1.5 Additionally, this test method has not been tested for applicability to organic substances and volatile matter.
1.6 This test method is not intended to provide leachates that are identical to the actual leachate produced from a solid material in the field or to produce leachates to be used as the so...

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Publication Date
30-Sep-2007
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ASTM D5744-07e1 - Standard Test Method for Laboratory Weathering of Solid Materials Using a Humidity Cell
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D5744–07
Standard Test Method for
Laboratory Weathering of Solid Materials Using a Humidity
1
Cell
This standard is issued under the fixed designation D5744; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
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´ NOTE—Editorial corrections made in April 2010.
1. Scope 1.6 This test method is not intended to provide leachates
that are identical to the actual leachate produced from a solid
1.1 This kinetic test method covers a laboratory weathering
material in the field or to produce leachates to be used as the
procedure that (1) enhances reaction-product transport in the
sole basis of engineering design.
aqueousleachofasolidmaterialsampleofspecifiedmass,and
1.7 Thistestmethodisnotintendedtosimulatesite-specific
(2)measuresratesofweathering-productmassrelease.Soluble
leaching conditions. It has not been demonstrated to simulate
weathering products are mobilized by a fixed-volume aqueous
actualdisposalsiteleachingconditions.Furthermore,thetestis
leachthatisperformedandcollectedweekly.Leachatesamples
not designed to produce effluents that are in chemical equilib-
are analyzed for pH, alkalinity/acidity, specific conductance,
rium with the solid phase sample.
sulfate, and other selected analytes.
1.8 This test method is intended to describe the procedure
1.1.1 This test method is intended for use to meet kinetic
for performing the laboratory weathering of solid materials to
testingregulatoryrequirementsforminingwasterockandores
generate leachates. It does not describe all types of sampling
sized to pass a 6.3-mm (0.25-in.) Tyler screen.
and analytical requirements that may be associated with its
1.1.2 Interlaboratory testing of this method has been con-
application.
fined to mine waste rock. Application of this test method to
1.9 The values stated in SI units are to be regarded as the
metallurgical-processing waste (for example, mill tailings) is
standard. The values given in parentheses are for information
outside the scope of the test method.
only.
1.2 This test method is a modification of a laboratory
1.10 This standard does not purport to address all of the
weathering procedure developed originally for mining wastes
2 safety concerns, if any, associated with its use. It is the
(1-3). However, it may have useful application wherever
responsibility of the user of this standard to establish appro-
gaseousoxidationcoupledwithaqueousleachingareimportant
priate safety and health practices and determine the applica-
mechanisms for contaminant mobility.
bility of regulatory limitations prior to use.
1.3 This test method calls for the weekly leaching of a
well-characterized solid material sample (weighing at least
2. Referenced Documents
1000-g), with water of specified purity, and the collection and
3
2.1 ASTM Standards:
chemical characterization of the resulting leachate. Test dura-
D75 Practice for Sampling Aggregates
tion is determined by the user’s objectives of the test.
D276 Test Methods for Identification of Fibers in Textiles
1.4 As described, this test method may not be suitable for
D420 Guide to Site Characterization for Engineering De-
some materials containing plastics, polymers, or refined met-
sign and Construction Purposes
als.These materials may be resistant to traditional particle size
D653 Terminology Relating to Soil, Rock, and Contained
reduction methods.
Fluids
1.5 Additionally, this test method has not been tested for
D737 Test Method for Air Permeability of Textile Fabrics
applicability to organic substances and volatile matter.
D1067 Test Methods for Acidity or Alkalinity of Water
D1125 Test Methods for Electrical Conductivity and Resis-
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tivity of Water
This test method is under the jurisdiction ofASTM Committee D34 on Waste
Management and is the direct responsibility of Subcommittee D34.01.04 on Waste
Leaching Techniques.
Current edition approved Oct. 1, 2007. Published November 2007. Originally
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approvedin1996.Lastpreviouseditionapprovedin2001asD5744-96(2001).DOI: For referenced ASTM standards, visit the ASTM website, www.astm.org, or
10.1520/D5744-07. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
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Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof Standards volume information, refer to the standard’s Document Summary page on
this standard. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D5744–07
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