ASTM E945-12

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Designation: E945 − 12
Standard Test Method for
Determination of Zinc in Zinc Ores and Concentrates by
1
EDTA Complexometric Titrimetry
This standard is issued under the fixed designation E945; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope erations for Chemical Analysis of Metals, Ores, and
Related Materials
1.1 This test method covers the determination of zinc in
E135 Terminology Relating to Analytical Chemistry for
ores, concentrates, and related materials having chemical
Metals, Ores, and Related Materials
composition within the following limits:
E173 Practice for Conducting Interlaboratory Studies of
Element Application Range, %
Methods for Chemical Analysis of Metals (Withdrawn
3
Zinc 5.0 to 70.0 1998)
Lead 0.5 to 50.0
E663 Practice for FlameAtomicAbsorptionAnalysis (With-
Copper 0.1 to 3.0
3
drawn 1997)
Iron 0.5 to 16.0
Sulfur 4.0 to 30.0 E882 Guide for Accountability and Quality Control in the
Calcium 0.1 to 20.0
Chemical Analysis Laboratory
Magnesium 0.1 to 10.0
E1601 Practice for Conducting an Interlaboratory Study to
Cadmium 0.1 to 8.0
Arsenic 0.01 to 1.0 Evaluate the Performance of an Analytical Method
Antimony 0.01 to 0.005
Bismuth 0.001 to 0.1
3. Terminology
Cobalt 0.1 to 0.5
Nickel 0.3 to 3.0
3.1 Definitions—For definitions of terms used in this test
Silver 0.00 to 150 oz/ton
method, refer to Terminology E135.
Gold 0.00 to 1.0 oz/ton
NOTE 1—As used in this test method, percent or “%” refers to a mass
4. Summary of Test Method
fraction.
4.1 The sample, after appropriate acid decomposition, is
1.2 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the evaporated to near dryness. The salts are dissolved in acid,
responsibility of the user of this standard to establish appro- interfering elements are removed, and the zinc is extracted as
priate safety and health practices and determine the applica- thiocyanate complex into MIBK. Zinc is determined in the
bility of regulatory limitations prior to use. extract by titrating with EDTA, using an internal indicator.
2. Referenced Documents 5. Significance and Use
2
2.1 ASTM Standards:
5.1 This test method is primarily intended to test materials
D1193 Specification for Reagent Water forcompliancewithcompositionalspecifications.Itisassumed
E29 Practice for Using Significant Digits in Test Data to
that all who use this test method will be trained analysts
Determine Conformance with Specifications working in properly equipped laboratories.
E50 Practices for Apparatus, Reagents, and Safety Consid-
5.2 Appropriate quality control practices shall be followed
such as those described in Guide E882.
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This test method is under the jurisdiction of ASTM Committee E01 on
6. Interferences
Analytical Chemistry for Metals, Ores, and Related Materials and is the direct
responsibility of Subcommittee E01.02 on Ores, Concentrates, and Related Metal-
6.1 With the exception of cadmium and cobalt, elements do
lurgical Materials.
not interfere if their compositional ranges are under the
CurrenteditionapprovedJune1,2012.PublishedJuly2012.Originallyapproved
maximum limits shown in 1.1.
in 1983. Last previous edition approved in 2007 as E945 – 07. DOI: 10.1520/
E0945-12.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
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E945 − 12
NOTE 2—The use of varying concentrations of EDTA solution allows
6.2 When the cadmium content is above 5.0 % in the
the volume of the titrant to be between 30 mL and 50 mL.
material to be analyzed, some of the cadmium is extracted and
Amount of
will titrate as zinc. The addition of potassium iodide before the
EDTA · 2H O EDTA Standard Zinc
2
titration serves to prevent the interference of cadmium. The
If the expected Mass, g/L Concentration Solution to
amount of potassium iodide solution to add in order to prevent
zinc is: Use
5%to20% 6.642 6g/L 10mL
the interference of cadmium is listed in 13.10.3.
20 % to 40 % 13.29 12 g/L 30 mL
6.3 Cobalt is extracted and titrated with the zinc. If the 40 % to 56 % 17.71 16 g/L 40 mL
56 % to 70 % 22.14 20 g/L 50 mL
cobalt content of the material to be analyzed is less than
8.8.2 Standardize the ED
...