Standard Practice for Sampling and Sample Preparation of Iron Ores and Related Materials

SCOPE
1.1 This practice covers procedures for mechanical sampling of iron ores and related materials in a falling stream or stopped-belt sampling and preparing the gross sample to the various test samples required for each characteristic to be measured. Included as Annexes are (1) design criteria to prevent bias, (2) statistical methods to determine quality variation and precisions of sampling and division, and (3) a method for comparing two sampling procedures for possible systematic differences.  
1.2 This standard does not purport to address all of the safety problems, 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. Specific precautionary statements are given in Section 8.

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Publication Date
09-May-1998
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ASTM E877-93(1998) - Standard Practice for Sampling and Sample Preparation of Iron Ores and Related Materials
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 877 – 93 (Reapproved 1998)
Standard Practice for
Sampling and Sample Preparation of Iron Ores and Related
Materials
This standard is issued under the fixed designation E 877; 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 3.1.1 bias—an error that is consistently positive or negative.
3.1.2 consignment—the total quantity of iron ore to be
1.1 This practice covers procedures for mechanical sam-
sampled.
pling of iron ores and related materials in a falling stream or
3.1.3 gross sample—the quantity of an ore consisting of all
stopped-belt sampling and preparing the gross sample to the
the increments taken from a consignment for any characteristic
various test samples required for each characteristic to be
or group of characteristics; also, the composite of all these
measured. Included as Annexes are (1) design criteria to
increments or subsamples each individually having been
prevent bias, (2) statistical methods to determine quality
crushed or divided, or both.
variation and precisions of sampling and division, and (3)a
3.1.4 increment—quantity of ore obtained by a sampling
method for comparing two sampling procedures for possible
device at one time with a single operation.
systematic differences.
3.1.5 iron ore—a naturally occurring material whose prin-
1.2 This standard does not purport to address all of the
cipal element of economic value is iron, or the products of
safety problems, if any, associated with its use. It is the
beneficiation or processing, other than metallization of mate-
responsibility of the user of this standard to establish appro-
rial, where iron remains or becomes the principal element of
priate safety and health practices and determine the applica-
economic value.
bility of regulatory limitations prior to use. Specific precau-
3.1.6 nominal size—the opening of the screen of the stan-
tionary statements are given in Section 8.
dard series that would pass 95 % of a representative sample of
2. Referenced Documents the consignment.
3.1.7 precision—a measure of reproducibility of test results,
2.1 ASTM Standards:
using the same equipment and method, statistically derived
E 276 Test Method for Particle Size or Screen Analysis at
from multiple data expressed at 95 % confidence level.
No. 4 (4.75-mm) Sieve and Finer for Metal-Bearing Ores
3.1.8 quality variation (s )—a measure of the variation of
w
and Related Materials
a characteristic within the consignment.
E 279 Test Method for Determination of Abrasion Resis-
3.1.9 stratum—quantity of an ore in routine sampling rep-
tance of Iron Ore Pellets and Sinter (Tumbler Test)
resented by one primary increment.
E 389 Test Method for Particle Size or Screen Analysis at
3.1.10 subsample—a quantity of an ore consisting of sev-
No. 4 (4.75-mm) Sieve and Coarser for Metal Bearing Ores
eral increments taken from a part of the consignment; also, a
and Related Materials
composite of several increments each individually having been
E 882 Guide for Accountability and Quality Control in the
crushed or divided, or both.
Chemical Analysis Laboratory
3.1.11 test sample—any sample for determination of size
E 1072 Test Method for Low Temperature Breakdown of
distribution, moisture content, physical properties, or chemical
Iron Ores
composition that is prepared from each increment, each sub-
3. Terminology
sample, or from the gross sample in accordance with the
specified method for that type of sample.
3.1 Definitions:
4. Summary of Practice
This practice is under the jurisdiction of ASTM Committee E-1 on Analytical
4.1 The precision required for the sampling and sample
Chemistry for Metals, Ores, and Related Materials and is the direct responsibility of
preparation steps are calculated based on the objectives of the
Subcommittee E01.02 on Ores, Slags, Refractories, Cement, and Related Oxide
Materials. testing, resulting in a sampling plan specifying the minimum
Current edition approved July 15, 1993. Published September 1993. Originally
weights and number of increments required for each step in the
published as E 877 – 82. Last previous edition E 877 – 82 (1986).
procedure. Samples are then collected, dried, blended, divided,
Annual Book of ASTM Standards, Vol 03.05.
crushed, pulverized, and ground as required by the test
Annual Book of ASTM Standards, Vol 03.06.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E 877
methods to be utilized. 7.2 Overall Precision (b ):
SDM
7.2.1 Overall precision for determining the mean values of
5. Significance and Use
the iron content, moisture content, and percentage passing the
5.1 This practice is to be used for sampling and sample
specified size sieve (in accordance with Methods E 276 and
preparation of iron ores and related materials, prior to use of a
E 389), at 95 % confidence in absolute percentage are as in
referee method for testing for compliance with compositional
Table 1.
specifications for metal content or physical properties. It is
7.2.2 Overall precisions for other characteristics shall be
assumed that all who use this procedure will be trained analysts
agreed upon between the parties concerned.
capable of performing common laboratory practices skillfully
NOTE 2—Nationally or internationally accepted measurement methods
and safely. It is expected that work will be performed in a
should be used to determine the characteristics desired.
properly equipped laboratory and that proper waste disposal
7.3 Equations:
procedures will be followed. Appropriate quality control prac-
tices must be followed, such as those described in Guide E 882. 7.3.1 Calculate overall precision as follows:
5.2 Adequate methods for obtaining representative samples
2 2
s 1 s
w DM
for testing the chemical and physical properties of a consign-
b 5 2 1 1 1 (1)
˛ S D
SDM
n c n
ment of iron ore are essential. The sale and use are dependent
or
on the chemical or physical properties, or both, of an ore.
5.3 The criteria to prevent bias may be used for both design
2 2
s s
s 1
D M
w
b 5 2 1 1 1 1 (2)
˛
of a sampling system and in checking the design of an existing SDM S D
n s n nm
system.
where:
6. Apparatus
b 5 overall precision for any characteristic,
SDM
6.1 Any mechanical sampler is acceptable that either by
s 5 estimated within-strata standard deviation of a
w
design or comparison, or both (as defined in Annex A1 and
characteristic,
Annex A4) can be shown to take nonbiased increments of at s 5 estimated standard deviation of division,
D
s 5 estimated standard deviation of measurement,
least minimum weight and number required and can handle
M
s 5 estimated standard deviation of division and
these increments in accordance with the practice.
DM
measurement combined,
6.2 Templates and Related Equipment, to obtain increments
n 5 number of primary increments,
from a stopped belt, with bias protection in accordance with
n5 number of final samples taken for measurement,
Annex A2, are acceptable.
m 5 number of measurements taken on each final
6.3 Riffle—A stationary sampler comprising an even num-
sample, and
ber of equally sized chutes, adjacent chutes discharging in
c 5 average number of secondary increments taken
opposite direction. For use with this practice, there must be a
per primary increment.
minimum of twelve chutes with an opening width of at least 3
times the nominal size.
NOTE 3—Factor (1 + 1/c) is omitted from the equation if only primary
increments are used.
NOTE 1—For fine ores (<3 mm) the 3 times nominal size should be
7.3.2 s and s or s , s , and s are estimated in
increased to the point where the plugging of chutes is eliminated. For
w DM w D M
coarse ores (>12.5 mm) it is recommended not to exceed 3 ⁄2 times accordance with Annex A3.
nominal size as it is required that the full width of the riffle be used since
7.3.3 When designing a new sampling installation, refer to
the accuracy of the split increases with the number of chutes. For
Annex A1 for estimating s and s .
w DM
free-flowing ores such as pellets, the 3 times top size may be reduced to
7.4 Selection of Sampling Parameters—Using the estimated
1 ⁄2 times provided it is ascertained that there is no chute plugging for a
values of s and s or s , s , and s and Eq1orEq2,
w DM w D M
particular ore type.
choose a combination of n, c, n, and m to obtain the required
6.4 Crushers—Crushers may be jaw, cone, rotary, or other
precision. It is recommended in routine sampling to use the
type that can reduce the particle size to the desired level
same value of c used in the determination of s .
w
without significant weight loss (less than 0.5 %) and not
7.5 Minimum Weight of Increment—The minimum weight
contaminate the sample.
of an increment is calculated by the following formula to
6.5 Pulverizers and Grinders—Pulverizers and grinders
ensure that a particle the shape of a cube of the nominal size
may be of plate, cylinder, or other type that can reduce the
shall not represent more than 10 % of its weight, to avoid bias
particle size to the desired level. They should be made of
by larger particles:
sufficiently hardened material to prevent contamination of the
sample. Also, the weight loss during pulverizing should not
TABLE 1 Overall Precision
exceed 2.5 %.
Iron and
Specification Size, Cumulative Percent Passing
Consignment, Moisture
7. Design of Sampling Operations
tons Content, <10 % 10–50 % >50–90 % >90 %
%
7.1 Basic Requirements:
A
>100 000 60.3 60.75 % 60.075C 60.075 (100-C) 60.75 %
7.1.1 The characteristics to be determined and precisions
20 000 to 100 000 60.4 61.0 % 60.1C 60.1 (100-C) 61.0 %
desired must be known.
<20 000 60.5 62.0 % 60.2C 60.2 (100-C) 62.0 %
7.1.2 The weight and special requirements for each test
A
sample must be known. C 5 cumulative passing, %.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E 877
completion of the movement of the consignment, additional
W 5 S /20! 3 sp gr/5! (3)
~ ~
increments shall be taken at the same interval until ore
where:
handling is complete.
W 5 minimum weight of increment, kg,
8.3 If secondary increments (c) are used, they shall be taken
S 5 nominal size of the ore, cm, and
at equal time intervals with a maximum time such that c is1or
sp gr 5 specific gravity of the iron ore being sampled.
greater.
NOTE 4—In practice, the weight of primary increments may be many 8.4 Increments are treated individually or combined to form
times greater than that obtained in Eq 3.
a gross sample(s) or subsamples, or both, in accordance with
final test sample requirements in conjunction with precision
7.6 Treatment of Increments—Increments will be handled
requirements, as determined in 7.4.1.
individually or combined to form one or more gross samples or
8.5 At this stage, individual test samples are obtained by a
set(s) of subsamples from which test sample(s) for the required
combination of division (weight reduction) (8.6), crushing and
characteristics will be taken. Each gross sample must follow
pulverizing (8.7), and drying (8.8), as directed in Section 8.
the requirements of sampling and preparation. Each gross
8.6 Division of gross sample, subsamples, or increment
sample must have, as a minimum number of increments, the
must conform with the following rule:
largest number (n) calculated from the individual characteris-
8.6.1 The minimum weight of the total divided sample must
tics taken from that gross sample.
be greater than:
7.6.1 Example—Assume a gross sample is required for iron
analysis and moisture determination and a separate gross 3
W 5 S 3 sp gr/5! (4)
~
sample for size distribution and tumble test. Also assume from
where:
5.4 the number of increments required to obtain precision
W 5 weight of the divided sample, kg
desired is as follows: 2
S 5 nominal size at that division level, cm, and
Moisture 30 increments
sp gr 5 specific gravity of the ore being sampled.
Iron 20 increments
Size 50 increments
The equation is based on the concept that the weight of the
Tumble 25 increments
largest piece should be less than 0.5 % of the weight of the
7.6.2 Example—Take 30 increments for iron analysis and divided sample.
moisture determination and 50 increments for size distribution
8.6.2 Divide the sample by one of the following procedures:
and tumble test, if the sampler has the capability (for example, (a) A mechanical sampler operated in accordance with the
computer controlled). If, however, alternative increments are
guidelines in Annex A1.
used, take 50 increments for each gross sample. If one gross (b) Riffling—Use a pan the same width as the riffle chutes to
sample is to be used for all the determinations, use 50
feed the ore for division. Add increments of ore to the pan and
increments. gently agitate the pan over the center of the chutes, feeding the
7.7 Special Precautions:
ore at a constant rate, so that any ore particle has an equal
7.7.1 Samples for size determination or other tests requiring chance of falling to either side of the device. Select the half of
uncrushed particles must be taken prior to crushing.
the divided sample to be included in subsequent sampling
7.7.2 Samples for moisture determination must be protected steps, at random. Thoroughly clean the equipment between
from ambient conditions. A subsample should be taken at least
samples.
every 8 h and the total moisture of the consignment should be
NOTE 5—Warning: Use proper dust collection to protect the operator
the weighted average of these samples. The 8-h period may be
from fine respirable dust particles.
extended provided the sample is protected from moisture
(c) Manual Increment Division (Note 6)—Mix the entire sample and
change (for example, refrigerated). To avoid moisture change,
spread on a flat nonmoisture-absorbing surface so that the sample forms a
samples must be prepared as quickly as possible, with mini-
rectangle of uniform thickness. Divide into at least 20 segments of equal
area. With a flat bottom, square-nose tool, take scoopfuls of approximate
mum handling, and must be kept in sealed containers while
equal size from each segment from the full depth of the bed. These
awaiting any stage of preparation prior to the initial weighing.
scoopfuls must have a minimum weight in accord
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