1、Designation: E 877 08Standard Practice forSampling and Sample Preparation of Iron Ores and RelatedMaterials for Determination of Chemical Composition1This standard is issued under the fixed designation E 877; the number immediately following the designation indicates the year oforiginal adoption or,
2、 in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers procedures for mechanical sam-pling of iron ores and relate
3、d materials in a falling stream orstopped-belt sampling and preparing the gross sample to thevarious test samples required for each characteristic to bemeasured. Included as Annexes are (1) design criteria toprevent bias, (2) statistical methods to determine qualityvariation and precisions of sampli
4、ng and division, and (3)amethod for comparing two sampling procedures for possiblesystematic differences.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and
5、 health practices and determine the applica-bility of regulatory limitations prior to use. Specific precau-tionary statements are given in Section 8.2. Referenced Documents2.1 ASTM Standards:2E 135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE 276 Test Method f
6、or Particle Size or Screen Analysis atNo. 4 (4.75-mm) Sieve and Finer for Metal-Bearing Oresand Related MaterialsE 279 Test Method for Determination of Abrasion Resis-tance of Iron Ore Pellets and Sinter by the Tumbler TestE 389 Test Method for Particle Size or Screen Analysis atNo. 4 (4.75-mm) Siev
7、e and Coarser for Metal-BearingOres and Related MaterialsE 882 Guide for Accountability and Quality Control in theChemical Analysis LaboratoryE 1072 Test Method for Low Temperature Breakdown ofIron Ores33. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminolo
8、gy E 135.3.1.1 nominal sizein sampling, the opening of the screenof the standard series that would pass 95 % of a representativesample.3.1.2 precisiona measure of reproducibility of test results,using the same equipment and method, statistically derivedfrom multiple data expressed at 95 % confidence
9、 level.4. Summary of Practice4.1 The precision required for the sampling and samplepreparation steps is calculated based on the objectives of thetesting, resulting in a sampling plan specifying the minimumweights and number of increments required for each step in theprocedure. Samples are then colle
10、cted, dried, blended, divided,crushed, pulverized, and ground as required by the testmethods to be utilized.5. Significance and Use5.1 This practice is to be used for sampling and samplepreparation of iron ores and related materials, prior to use of areferee method for testing for compliance with co
11、mpositionalspecifications for metal content or physical properties. It isassumed that all who use this procedure will be trained analystscapable of performing common laboratory practices skillfullyand safely. It is expected that work will be performed in aproperly equipped laboratory and that proper
12、 waste disposalprocedures will be followed. Appropriate quality control prac-tices must be followed, such as those described in Guide E 882.5.2 Adequate methods for obtaining representative samplesfor testing the chemical and physical properties of a consign-ment of iron ore are essential. The sale
13、and use are dependenton the chemical or physical properties, or both, of an ore.5.3 The criteria to prevent bias may be used for both designof a sampling system and in checking the design of an existingsystem.6. Apparatus6.1 Any mechanical sampler is acceptable that either bydesign or comparison, or
14、 both (as defined in Annex A1 andAnnex A4) can be shown to take nonbiased increments of at1This practice is under the jurisdiction of ASTM Committee E01 on AnalyticalChemistry for Metals, Ores, and Related Materials and is the direct responsibility ofSubcommittee E01.02 on Ores, Concentrates, and Re
15、lated Metallurgical Materials.Current edition approved Nov. 1, 2008. Published December 2008. Originallyapproved in 1982. Last previous edition approved in 2003 as E 877 03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For A
16、nnual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 1942
17、8-2959, United States.least minimum weight and number required and can handlethese increments in accordance with the practice.6.2 Templates and Related Equipment, to obtain incrementsfrom a stopped belt, with bias protection in accordance withAnnex A2, are acceptable.6.3 RiffleA stationary sampler c
18、omprising an even num-ber of equally-sized, adjacent chutes discharging in oppositedirections. For use with this practice, there must be a minimumof twelve chutes with an opening width of at least 3 times thenominal size.NOTE 1For fine ores ( 12.5 mm) it is recommended not to exceed 312 timesnominal
19、 size as it is required that the full width of the riffle be used sincethe accuracy of the split increases with the number of chutes. Forfree-flowing ores such as pellets, the 3 times top size may be reduced to112 times provided it is ascertained that there is no chute plugging for aparticular ore t
20、ype.6.4 CrushersCrushers may be jaw, cone, rotary, or othertype that can reduce the particle size to the desired levelwithout significant weight loss (less than 0.5 %) and notcontaminate the sample.6.5 Pulverizers and GrindersPulverizers and grindersmay be of plate, cylinder, or other type that can
21、reduce theparticle size to the desired level. They should be made ofsufficiently hardened material to prevent contamination of thesample. Also, the weight loss during pulverizing should notexceed 2.5 %.7. Design of Sampling Operations7.1 Basic Requirements:7.1.1 The characteristics to be determined
22、and precisionsdesired must be known.7.1.2 The weight and special requirements for each testsample must be known.7.2 Overall Precision (bSDM):7.2.1 Overall precision for determining the mean values ofthe iron content, moisture content, and percentage passing thespecified size sieve (in accordance wit
23、h Test Methods E 276and E 389), at 95 % confidence in absolute percentages are asin Table 1.7.2.2 Overall precisions for other characteristics shall beagreed upon between the parties concerned.NOTE 2Nationally or internationally accepted measurement methodsshould be used to determine the characteris
24、tics desired.7.3 Equations:7.3.1 Calculate overall precision as follows:bSDM5 2sw2nS1 11cD1s2DMn(1)orbSDM5 2sw2nS1 11sD1sD2n1sM2nm(2)where:bSDM= overall precision for any characteristic,sw= estimated within-strata standard deviation of acharacteristic,sD= estimated standard deviation of division,sM=
25、 estimated standard deviation of measurement,sDM= estimated standard deviation of division andmeasurement combined,n = number of primary increments,n = number of final samples taken for measurement,m = number of measurements taken on each finalsample, andc = average number of secondary increments ta
26、kenper primary increment.NOTE 3Factor (1 + 1/c) is omitted from the equation if only primaryincrements are used.7.3.2 swand sDMor sw, sD, and sMare estimated inaccordance with Annex A3.7.3.3 When designing a new sampling installation, refer toAnnex A1 for estimating swand sDM.7.4 Selection of Sampli
27、ng ParametersUsing the estimatedvalues of swand sDMor sw, sD, and sMandEq1orEq2,choose a combination of n, c, n, and m to obtain the requiredprecision. It is recommended in routine sampling to use thesame value of c used in the determination of sw.7.5 Minimum Weight of IncrementThe minimum weightof
28、an increment is calculated by the following formula toensure that a particle the shape of a cube of the nominal sizeshall not represent more than 10 % of its weight, to avoid biasby larger particles:W 5 S3/20! 3 sp gr/5! (3)where:W = minimum weight of increment, kg,S = nominal size of the ore, cm, a
29、ndsp gr = specific gravity of the iron ore being sampled.NOTE 4In practice, the weight of primary increments may be manytimes greater than that obtained in Eq 3.7.6 Treatment of IncrementsIncrements will be handledindividually or combined to form one or more gross samples orset(s) of subsamples from
30、 which test sample(s) for the requiredcharacteristics will be taken. Each gross sample must followthe requirements of sampling and preparation. Each grosssample must have, as a minimum number of increments, thelargest number (n) calculated from the individual characteris-tics taken from that gross s
31、ample.TABLE 1 Overall PrecisionConsignment,tonsIron andMoistureContent,%Specification Size, Cumulative Percent Passing50%90%A90% 100 000 6 0.3 6 0.75 % 6 0.075C 6 0.075 (100-C) 6 0.75 %20 000 to 100 000 6 0.4 6 1.0 % 6 0.1C 6 0.1 (100-C) 6 1.0 %20000 6 0.5 6 2.0 % 6 0.2C 6 0.2 (100-C) 6 2.0 %AIn the
32、 formulae for calculating the precision estimates within this column,C = cumulative percent passing.E8770827.6.1 ExampleAssume a gross sample is required for ironanalysis and moisture determination and a separate grosssample for size distribution and tumble test. Also assume from7.4 the number of in
33、crements required to obtain precisiondesired is as follows:Moisture 30 incrementsIron 20 incrementsSize 50 incrementsTumble 25 increments7.6.2 ExampleTake 30 increments for iron analysis andmoisture determination and 50 increments for size distributionand tumble test, if the sampler has the capabili
34、ty (for example,computer controlled). If, however, alternative increments areused, take 50 increments for each gross sample. If one grosssample is to be used for all the determinations, use 50increments.7.7 Special Precautions:7.7.1 Samples for size determination or other tests requiringuncrushed pa
35、rticles must be taken prior to crushing.7.7.2 Samples for moisture determination must be protectedfrom ambient conditions. A subsample should be taken at leastevery 8 h and the total moisture of the consignment should bethe weighted average of these samples. The 8-h period may beextended provided th
36、e sample is protected from moisturechange (for example, refrigerated). To avoid moisture change,samples must be prepared as quickly as possible, with mini-mum handling, and must be kept in sealed containers whileawaiting any stage of preparation prior to the initial weighing.Moisture samples should
37、not be crushed below14-in. sieve (6.3mm) and the minimum weight of samples used should conformwith Eq 4 (8.6.1). Mix sample prior to moisture determination.8. Sampling and Preparation Procedure (See Fig. 3 forexamples)8.1 Collect throughout the movement of the consignment, inaccordance with Annex A1
38、 or Annex A2, the number ofprimary increments, as determined in 7.4 (with a minimum of20). Start at random within the first stratum, then sample atequal mass or time intervals. If the ore is handled in such a waythat there is a cycle to the variability of a characteristic, it mustbe ascertained that
39、 the sampling cycle is not in phase with thehandling cycle.8.2 If the required number of increments is collected prior tocompletion of the movement of the consignment, additionalincrements shall be taken at the same interval until orehandling is complete.8.3 If secondary increments (c) are used, the
40、y shall be takenat equal time intervals with a maximum time such that c is1orgreater.8.4 Increments are treated individually or combined to forma gross sample(s) or subsamples, or both, in accordance withfinal test sample requirements in conjunction with precisionrequirements, as determined in 7.3.1
41、.8.5 At this stage, individual test samples are obtained by acombination of division (weight reduction) (8.6), crushing andpulverizing (8.7), and drying (8.8), as directed in Section 8.8.6 Division of gross sample, subsamples, or incrementmust conform with the following rule:8.6.1 The minimum weight
42、 of the total divided sample mustbe greater than:W25 S33 sp gr/5! (4)where:W2= weight of the divided sample, kgS = nominal size at that division level, cm, andsp gr = specific gravity of the ore being sampled.8.6.1.1 The equation is based on the concept that the weightof the largest piece should be
43、less than 0.5 % of the weight ofthe divided sample.8.6.2 Divide the sample by one of the following procedures:8.6.2.1 A mechanical sampler operated in accordance withthe guidelines in Annex A1.8.6.2.2 RifflingUse a pan the same width as the rifflechutes to feed the ore for division.Add increments of
44、 ore to thepan and gently agitate the pan over the center of the chutes,feeding the ore at a constant rate, so that any ore particle has anequal chance of falling to either side of the device. Select thehalf of the divided sample to be included in subsequentsampling steps, at random. Thoroughly clea
45、n the equipmentbetween samples. WarningUse proper dust collection toprotect the operator from fine respirable dust particles.8.6.2.3 Manual Increment Division (Note 5)Mix the en-tire sample and spread on a flat nonmoisture-absorbing surfaceso that the sample forms a rectangle of uniform thickness.Di
46、vide into at least 20 segments of equal area. With a flatbottom, square-nose tool, take scoopfuls of approximate equalsize from each segment from the full depth of the bed. Thesescoopfuls must have a minimum weight in accordance with Eq3. Combine the scoopfuls to form the divided sample.NOTE 5Manual
47、 increment division, although very efficient for moistor cohesive ores, or both, is not recommended for dry ores, sinter, orpellets.8.7 Drying, Crushing, Pulverizing, and Grinding:8.7.1 Always dry samples before sample preparation, ifpossible, to limit contamination from moist ore sticking tosurface
48、s of sample preparation equipment.8.7.2 Crush, pulverize, and grind samples to the requiredmaximum size in stages convenient to the equipment available.At each stage, reduce the sample weight to the extent that theweight of the divided sample exceeds that obtained by Eq 4.WarningUse proper dust coll
49、ection to protect the operatorfrom fine respirable dust particles.8.8 DryingDrying of any portion of the sample is accom-plished in any heating medium as long as the ore temperaturedoes not exceed 110 C. Where specifications call for a driedsample, it must be dried to constant weight in an oven capableof maintaining a temperature of 105 C 6 5 C. Constantweight is obtained when an additional hour drying at 105 C 65 C does not cause a change greater than 0.05 % weight.NOTE 6The maximum temperature of 110 C may be exceeded,provided it is ascertained
