ASTM E314-00(2005)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:E314–00(Reapproved2005)
Standard Test Methods for
Manganese in Iron Ores
This standard is issued under the fixed designation E314; 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 Methods for Chemical Analysis of Metals
E877 Practice for Sampling and Sample Preparation of Iron
1.1 These test methods cover the determination of manga-
Ores and Related Materials for Determination of Chemical
nese in iron ores, concentrates, and agglomerates. The follow-
Composition
ing two test methods are included:
E882 Guide for Accountability and Quality Control in the
Sections
Chemical Analysis Laboratory
Test Method A (Pyrophosphate (Potentiometric)) 7-15
Test Method B (Periodate (Photometric)) 16-21
E1601 Practice for Conducting an Interlaboratory Study to
Evaluate the Performance of an Analytical Method
1.2 Test Method A covers the determination of manganese
in the concentration range from 2.5 to 15.0 %. Test Method B
3. Terminology
covers the determination of manganese in the concentration
3.1 Definitions—For definitions of terms used in this test
range of 0.01 to 5.00 %.
method, refer to Terminology E135.
NOTE 1—The lower limit for this test method is set at 50 % relative
error for the lowest grade material tested in the interlaboratory study in
4. Significance and Use
accordance with Practice E1601.
4.1 This test method is intended to be used for compliance
1.3 The values stated in SI units are to be regarded as
with compositional specifications for manganese content in
standard. No other units of measurement are included in this
iron ores, concentrates, and agglomerates. It is assumed that all
standard.
who use these procedures will be trained analysts capable of
1.4 This standard does not purport to address all of the
performing common laboratory procedures skillfully and
safety concerns, if any, associated with its use. It is the
safely. It is expected that work will be performed in a properly
responsibility of the user of this standard to establish appro-
equipped laboratory and that proper waste disposal procedures
priate safety and health practices and determine the applica-
will be followed.Appropriate quality control practices must be
bility of regulatory limitations prior to use.
followed such as those described in Guide E882.
2. Referenced Documents
5. Reagents and Materials
2.1 ASTM Standards:
5.1 Purity and Concentration of Reagents—The purity and
E50 Practices for Apparatus, Reagents, and Safety Consid-
concentration of the common chemical reagents used shall
erations for Chemical Analysis of Metals, Ores, and
conform to Practices E50. Special apparatus and reagents
Related Materials
required are located in separate sections preceding the proce-
E135 Terminology Relating to Analytical Chemistry for
dure.
Metals, Ores, and Related Materials
6. Hazards
E173 Practice for Conducting Interlaboratory Studies of
6.1 For precautions to be observed in this method, refer to
Practices E50.
These test methods are under the jurisdiction of ASTM Committee E01 on
Analytical Chemistry for Metals, Ores, and Related Materials and are the direct
7. Sampling and Sample Preparation
responsibility of Subcommittee E01.02 on Ores, Concentrates, and Related Metal-
lurgical Materials. 7.1 The gross sample shall be collected and prepared in
Current edition approved Oct. 1, 2005. Published October 2005. Originally
accordance with Practice E877.
approved in 1966. Last previous edition approved in 2000 as E314 – 00. DOI:
7.2 The analytical sample shall be pulverized to pass a No.
10.1520/E0314-00R05.
100 (150-µm) sieve.
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
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. Withdrawn.
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E314–00 (2005)
NOTE 2—To facilitate decomposition some ores, such as specular
containing water. Prior to measuring the pH of a solution the
hematites, may require grinding to pass a No. 200 (75-µm) sieve.
electrodes must be thoroughly washed with water especially if
they have been left standing for a long period of time.
TEST METHOD A—PYROPHOSPHATE
10.2 Potentiometric Titration Apparatus—Instruments for
(POTENTIOMETRIC) METHOD
detectingtheendpointsinpH(acid-base),oxidation-reduction,
precipitation, and complexation titrations consist of a pair of
8. Summary of Test Method
suitable electrodes, a potentiometer, a buret, and a motor-
8.1 The test sample is decomposed by treatment with
driven stirrer. Titrations are based on the fact that when two
hydrochloric, nitric, hydrofluoric, and perchloric acids. After
dissimilarelectrodesareplacedinasolutionthereisapotential
the addition of sodium pyrophosphate and the adjustment of
difference between them. This potential difference depends on
the acidity, the manganese is determined by oxidation to
the composition of the solution and changes as the titrant is
trivalent manganese with a standard solution of potassium
added. A high-impedance electronic voltmeter follows the
permanganate. The end point is determined potentiometrically.
changes accurately. The end point of the titration may be
determined by adding the titrant until the potential difference
9. Interferences
attains a predetermined value or by plotting the potential
9.1 Provision has been made for the removal of chromium
difference versus the titrant volume, the titrant being added
which under some conditions is an interfering element.
until the end point has been passed.
10.2.1 An elaborate or highly sensitive and accurate poten-
10. Apparatus
tiometer is not necessary for potentiometric titrations because
10.1 pH Meter—A number of pH meters are commercially
the absolute cell voltage needs to be known only approxi-
available. Many of these instruments can accept a variety of
mately, and variations of less than 1 MV are not significant.
electrodes and therefore can be used also for potential mea-
Such instruments should have a range of about 1.5 V and a
surements.Although both line- and battery-operated pH meters
readability of about 1 MV. Many of the pH meters are also
are manufactured, the former is recommended for laboratory
suitable for potentiometric titrations.
work because this type of pH meter contains an electronic or
10.2.2 The electrode system must consist of a reference
transistorized potentiometer which makes the emf balancing
electrode and an indicator electrode. The reference electrode
operation entirely automatic. Electrometer tube input is used
maintains a constant, but not necessarily a known or reproduc-
on both the electronic and transistorized pH meters.
ible potential during the titration. The potential of the indicator
10.1.1 The pH meter must have electrode standardization
electrodedoeschangeduringthetitration;further,theindicator
(or asymmetry potential) and manual or automatic temperature
electrode must be one that will quickly come to equilibrium.A
compensation controls. The dial must read in pH directly, and
platinum indicator electrode and reference electrode are re-
permit readings that are accurate to at least 60.01 pH unit. For
quired for this method.
higher accuracies it is recommended that a pH meter with an
10.2.3 Initially, a titration of the constituent in question is
expanded scale be used.
performed manually, and the volumes of titrant added and the
10.1.2 Because there is no accurate method for determining
corresponding potential differences are noted. By use of
theabsolutepotentialofanindividualelectrode,twoelectrodes
established techniques the end point potential is determined.
are used for pH measurements. These are called the reference
For the analytical determinations, titration may be continued to
and indicator electrodes. By international agreement the hy-
a preset potential, the end point being signaled by a null meter,
drogen electrode is the standard indicator electrode for pH, but
with or without automatic termination of the titration. This
is inconvenient to use and subject to several limitations. The
technique is applicable to reasonably rapid reactions involving
most widely used reference electrode is the saturated calomel
strong oxidants and reductants, precipitates not more soluble
electrode. It is most often used as a pencil-type unit that is
than silver chloride, and ionization constants greater than that
immersed directly in the solution, but may also be utilized as
of boric acid.
an external cell (to prevent possible contamination) contacting
10.2.4 Other techniques may be used for both slow and fast
the solution by means of a salt bridge. The silver-silver
reactions. These include automatic recording of the titration
chloride reference electrode is also convenient to use, but it is
curve on a strip chart, and the recording of the titrant end point
more difficult to prepare than the saturated calomel electrode.
volume on a tape. In the latter, an adjustable print-out delay
The mercurous sulfate reference electrode may be used in
prevents undertitrating when the reaction is slow.
solutions in which the chloride ions that diffuse out of the
10.3 Magnetic Stirrer—Use of a TFE-fluorocarboncovered
calomel cell might be harmful.
stirring bar is recommended.
10.1.3 The most commonly employed indicator electrode is
the glass electrode. The quinhydrone and antimony-
11. Reagents
antimonous oxide electrodes are used to a much lesser extent.
11.1 Hydrochloric Acid (sp gr 1.19)—Concentrated hydro-
Combination electrodes containing both the indicator and
chloric acid (HCl).
reference units are also available. The tips of the electrodes
11.2 Hydrochloric Acid (1 + 1)—Mix 1 volume of concen-
containing solutions must be covered with rubber caps when
trated HCl (sp gr 1.19) with 1 volume of water.
the electrodes are disconnected from the meter and stored.
When pH measurements are not being made the electrodes 11.3 HydrochloricAcid (1 + 10)—Mix1volumeofconcen-
connected to the pH meter should be kept in a beaker trated HCl (sp gr 1.19) with 10 volumes of water.
E314–00 (2005)
TABLE 1 Precision Data
11.4 Hydrofluoric Acid (48 %)—Concentrated hydrofluoric
acid (HF). Number of Number of
Relative Standard
A
Average Concentration, % Deter- Participating
B
11.5 Hydrogen Peroxide (3 %)—Mix 1 volume of concen- Deviation, %
minations Laboratories
trated hydrogen peroxide (H O , 30 %) with 9 volumes of
2 2
2.80 61.87 14 7
water.
4.12 61.75 14 7
5.53 61.16 14 7
11.6 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
7.81 60.68 14 7
(HNO ).
3 10.09 61.02 14 7
A
11.7 Perchloric Acid (70 %)—(HClO ).
Each concentration represents a different kind of iron ore.
B
RelativeStandardDeviation, RSD,inthistestmethodiscalculatedasfollows:
11.8 Potassium Permanganate, Standard Solution (0.1 N)
RSD 5 100/¯X (d /n–1
~ != !
11.8.1 Preparation—Dissolve 3.2 g of potassium perman-
where:
ganate (KMnO ) in 1 L of water. Let stand in the dark for 2
¯
X = average concentration, %,
weeks. Filter, without washing, through a Gooch crucible or a
d = difference of the determination from the mean, and
fine porosity fritted-glass crucible. Avoid contact with rubber
n = number of determinations, and in this case n = 7 as each value used is
the average of two determinations from each laboratory.
or other organic material. Store in a dark-colored glass-
stoppered bottle.
11.8.2 Standardization—Dry a portion of the National In-
12. Procedure
stituteofStandardsandTechnologystandardsampleofsodium
12.1 Transfer approximately 0.5000 g of prepared sample to
oxalate at 105°C. Transfer 0.3000 g of the sodium oxalate to a
a small dry weighing bottle and place in a drying oven. After
600-Lbeaker.Add 250 mLof H SO (5+95) previously boiled
2 4
dryingat105to110°C(Note6)for1h,capthebottle,andcool
for 10 to 15 min and then cooled to 27 6 3°C, and stir until the
to room temperature in a desiccator. Momentarily release the
oxalatehasdissolved.Add39to40mL(Note3)oftheKMnO
cap to equalize pressure and weigh the capped bottle to the
solution,atarateof25to35mL/min,whilestirringslowly.Let
nearest 0.0001 g. Repeat the drying and weighing until there is
standuntilthepinkcolordisappears(about45s)(Note4).Heat
no further weight loss. Transfer the test sample to a 600-mL
to 55 to 60°C and complete the titration by adding KMnO
beaker and reweigh the capped bottle to the nearest 0.0001 g.
solution until a faint pink color persists for 30 s. Add the last
Thedifferencebetweenthetwoweightsistheweightofthetest
0.5 to 1 mL dropwise, allowing each drop to become decol-
sample.
orized before adding the next drop. To determine the blank:
Titrate 250 mL of H SO (5+95), treated as above, with
2 4 NOTE 6—Most ores yield their hygroscopic moisture at the specified
KMnO solution to a faint pink color. The blank correction is
temperature. However, in the case of some ores, higher drying tempera-
tures may be required.
usually equivalent to 0.03 3 0.05 mL.
12.2 Moisten the test sample with a few millilitres of water,
NOTE 3—A 0.3000-g portion of sodium oxalate requires 44.77 mL of
add 20 mL of HCl, cover, and heat below boiling. When all
KMnO solution (0.1 N).
soluble minerals are decomposed, add 10 mL of HNO,4to5
NOTE 4—If the KMnO solution is too strong, the pink color will not
mLof HF, and 15 mLof HClO and evaporate without a cover
fade at this point; begin again, adding a few millilitres less of the KMnO 4
to copious fumes of HClO . Cool, and rinse down the sides of
solution.
the beaker and dissolve the salts in 10 mL of water (Note 7).
11.9 Potassium Permanganate, Standard Solution (0.05 N)
Cover and again evaporate to fumes HClO and fume strongly
(Note 5)—Dilute 1 volume of 0.1 N potassium permanganate
for 1 min. Withdraw the cover slightly and volatilize any
solution with 1 volume of water. Standardize using 0.1500 g of
chromium present by the drop-wise addition of HCl. When
sodium oxalate as described under 11.8.2. Confirm the stan-
chromyl chloride has been expelled, as indicated by the
dardization against an ore of known manganese content by
absence of orange vapor on the addition of HCl, replace the
carrying the known sample through all steps of the procedure.
coverandevaporatetoabout3mLoruntilthesaltsformonthe
bottomofthebeaker.Cool,add10mLofHCl(1 + 1)and1mL
NOTE 5—The 0.05 normality of the potassium permanganate (KMnO )
...