ASTM E2941-13

Standard Practice for Nitric Acid-Extraction of Elements from Ores and Related Metallurgical Materials by Closed Vessel Microwave Heating

SIGNIFICANCE AND USE
5.1 These test methods are primarily intended to test materials for compliance with compositional specifications and for monitoring. Partial extraction of ores and related metallurgical materials can provide information on the availability of elements to leaching, water quality changes, or other site conditions.  
5.2 Rapid heating, in combination with temperatures in excess of the atmospheric boiling point of HNO3, reduces sample preparation or reaction times.  
5.3 Little or no acids are lost to boiling or evaporation in the closed digestion vessel so additional portions of acid may not be required. Increased blank corrections from trace impurities in acid are minimized.  
5.4 It is assumed that the users of this practice will be trained analysts capable of performing common laboratory procedures skillfully and safely. It is expected that work will be performed in a properly equipped laboratory and that proper waste disposal procedures will be followed. Appropriate quality control practices such as those described in Guide E882 must be followed.
SCOPE
1.1 This practice covers the digestion of ores and related metallurgical materials, such as mine soil, waste rock and tailings, for subsequent determination of nitric acid-extractable contents of certain elements by such solution analytical techniques as atomic absorption, atomic emission (see Method D1976), and inductively coupled plasma mass spectroscopy (see Method D5673).  
1.1.1 Contents of aluminum, antimony, arsenic, barium, beryllium, bismuth, boron, cadmium, calcium, chromium, cobalt, copper, gallium, iron, lead, lithium, magnesium, manganese, mercury, molybdenum, nickel, phosphorus, potassium, scandium, selenium, silver, sodium, strontium, thallium, tin, titanium, vanadium and zinc can be extracted from ores and related metallurgical materials for determination by analytical methods for elements in solution. Other elements may be determined from extracts produced using this practice.  
1.1.2 Actual element quantification can be accomplished by following the various test methods under other appropriate ASTM standards for element(s) of interest in solution.  
1.1.3 The detection limit and linear content range for each element is dependent on the atomic absorption or emission spectrometric technique employed and may be found in the manual accompanying the instrument used or ASTM standard method for analysis of the solutions. Take into account the 100 fold dilution due to digesting a 1-g sample to final volume of 100 mL.  
1.1.4 The extent of extraction of elements from ores and related metallurgical materials by this method is dependent upon the physical and mineralogical characteristics of the prepared sample.  
1.2 The values stated SI units are to be regarded as the standard. No other units of measurements are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 9.

General Information

• Status: Historical
• Publication Date: 30-Sep-2013
• ICS: 73.060.01 - Metalliferous minerals in general
• Technical Committee: E01 - Analytical Chemistry for Metals, Ores, and Related Materials
• Drafting Committee: E01.02 - Ores, Concentrates, and Related Metallurgical Materials

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: E2941 − 13
StandardPractice for
Nitric Acid-Extraction of Elements from Ores and Related
Metallurgical Materials by Closed Vessel Microwave
Heating
This standard is issued under the fixed designation E2941; 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.
1. Scope 1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This practice covers the digestion of ores and related
responsibility of the user of this standard to establish appro-
metallurgical materials, such as mine soil, waste rock and
priate safety and health practices and determine the applica-
tailings,forsubsequentdeterminationofnitricacid-extractable
bility of regulatory limitations prior to use. For specific hazard
contents of certain elements by such solution analytical tech-
statements, see Section 9.
niques as atomic absorption, atomic emission (see Method
D1976), and inductively coupled plasma mass spectroscopy
2. Referenced Documents
(see Method D5673).
2.1 ASTM Standards:
1.1.1 Contents of aluminum, antimony, arsenic, barium,
D1193Specification for Reagent Water
beryllium, bismuth, boron, cadmium, calcium, chromium,
D1976Test Method for Elements in Water by Inductively-
cobalt, copper, gallium, iron, lead, lithium, magnesium,
Coupled Argon Plasma Atomic Emission Spectroscopy
manganese, mercury, molybdenum, nickel, phosphorus,
D5258Practice forAcid-Extraction of Elements from Sedi-
potassium, scandium, selenium, silver, sodium, strontium,
ments Using Closed Vessel Microwave Heating
thallium, tin, titanium, vanadium and zinc can be extracted
D5673Test Method for Elements in Water by Inductively
fromoresandrelatedmetallurgicalmaterialsfordetermination
Coupled Plasma—Mass Spectrometry
by analytical methods for elements in solution. Other elements
E50Practices for Apparatus, Reagents, and Safety Consid-
may be determined from extracts produced using this practice.
erations for Chemical Analysis of Metals, Ores, and
1.1.2 Actual element quantification can be accomplished by
Related Materials
following the various test methods under other appropriate
E135Terminology Relating to Analytical Chemistry for
ASTM standards for element(s) of interest in solution.
Metals, Ores, and Related Materials
1.1.3 The detection limit and linear content range for each
E882Guide for Accountability and Quality Control in the
element is dependent on the atomic absorption or emission
Chemical Analysis Laboratory
spectrometric technique employed and may be found in the
2.2 Federal Standard:
manual accompanying the instrument used orASTM standard
CFR Title 21,Part 1030, and Title 47, Part 18
methodforanalysisofthesolutions.Takeintoaccountthe100
fold dilution due to digesting a 1-g sample to final volume of
3. Terminology
100 mL.
3.1 Definitions—For definitions of terms used in this
1.1.4 The extent of extraction of elements from ores and
practice, refer to Terminology E135.
related metallurgical materials by this method is dependent
upon the physical and mineralogical characteristics of the
4. Summary of Practice
prepared sample.
4.1 Thechemicalportionofthispracticeinvolvesnitricacid
1.2 The values stated SI units are to be regarded as the
digestion to dissociate the elements not interstitially bound in
standard. No other units of measurements are included in this
silicate lattices.
standard.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
This test method is under the jurisdiction of ASTM Committee E01 on contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Analytical Chemistry for Metals, Ores, and Related Materials and is the direct Standards volume information, refer to the standard’s Document Summary page on
responsibility of Subcommittee E01.02 on Ores, Concentrates, and Related Metal- the ASTM website.
lurgical Materials. AvailablefromU.S.GovernmentPrintingOfficeSuperintendentofDocuments,
Current edition approved Oct. 1, 2013. Published October 2013. DOI: 10.1520/ 732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http://
E2941-13. www.access.gpo.gov.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2941 − 13
4.2 ThesampleisdigestedwithHNO inaclosedfluoropo- microwave leakage. The system should have Federal Commu-
lymer vessel using microwave heating to an internal pressure nications Commission (FCC) type approval for operations
of 6.89 × 10 Pa. under FCC Rule Part 18.
7.1.1 Digestion Vessels—A vessel of 100-mL capacity. The
4.3 This practice provides a sample suitable for analysis by
vesselmustbetransparenttomicrowaveenergyandbecapable
atomic absorption, atomic emission or inductively coupled
of withstanding a minimum internal pressure of 8.27 × 10 Pa,
plasma mass spectrometry.
and a temperature of 200 °C. The vessel must contain a safety
pressure relief valve, a rupture disc, pressure venting system,
5. Significance and Use
or be connected to an external safety relief valve that will
5.1 These test methods are primarily intended to test mate-
prevent possible vessel rupture or ejection of the vessel cap.
rials for compliance with compositional specifications and for
7.1.2 Pressure Control Vessel—Avesselof100mLcapacity,
monitoring. Partial extraction of ores and related metallurgical
transparent to microwave energy, with a port for connection to
materials can provide information on the availability of ele-
a pressure control device and capable of withstanding a
ments to leaching, water quality changes, or other site condi- 5
minimuminternalpressureof8.27×10 Paandtemperatureof
tions.
200 °C.
5.2 Rapid heating, in combination with temperatures in 7.1.3 Pressure Control Device—An externally or internally
excess of the atmospheric boiling point of HNO , reduces
operated device to control the pressure within the digestion
sample preparation or reaction times. vessels. The controller must be capable of 6.89 × 10 Pa
adjustments, controlling up to 8.27 × 10 Pa and be equipped
5.3 Littleornoacidsarelosttoboilingorevaporationinthe
with an external pressure relief valve if a non-venting control
closed digestion vessel so additional portions of acid may not
vessel is used.
be required. Increased blank corrections from trace impurities
in acid are minimized. 7.2 Other commercially available laboratory microwave
heating systems may be used so long as they can be shown to
5.4 It is assumed that the users of this practice will be
provide comparable safety and performance. Follow manufac-
trained analysts capable of performing common laboratory
turers instruction for use.
proceduresskillfullyandsafely.Itisexpectedthatworkwillbe
performed in a properly equipped laboratory and that proper
8. Reagents
waste disposal procedures will be followed.Appropriate qual-
8.1 Purity of Reagents—Reagent grade chemicals shall be
ity control practices such as those described in Guide E882
used in all tests. Unless otherwise indicated, it is intended that
must be followed.
all reagents shall conform to the specifications of the commit-
tee onAnalytical Reagents of theAmerican Chemical Society,
6. Interferences
where such specifications are available. Other grades may be
6.1 No interferences to the digestion of ores and related
used provided it is first ascertained that the reagent is of
metallurgical materials using microwave heating have been
sufficiently high purity to permit its use without lessening the
observed.
accuracy of the determination.
6.2 Precautions should be exercised to avoid those interfer-
8.2 Purity of Water—Unless otherwise indicated, references
ences normally associated with the final determination of
towatershallbeunderstoodtomeanreagentwaterconforming
elements using atomic absorption, atomic emission, or induc-
to Type I or Type II of Specification D1193. Type III or Type
tively coupled plasma mass spectrometry.
IV may be used if they effect no measurable change in the
6.3 The HNO matrix may not be suitable for stabilizing blank or sample.
solutionscontainingsilverandantimony,analternatedigestion
9. Hazards
methodusingaHClmatrixmayberequiredtodeterminesome
9.1 Ope
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