1、Designation: E 877 03Standard Practice forSampling and Sample Preparation of Iron Ores and RelatedMaterials1This standard is issued under the fixed designation E 877; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、 revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 related materials in a falling stream orstopped
3、-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 sampling and division, and (3)amethod for compa
4、ring two sampling procedures for possiblesystematic differences.1.2 This standard does not purport to address all of thesafety problems, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the appli
5、ca-bility of regulatory limitations prior to use. Specific precau-tionary statements are given in Section 8.2. Referenced Documents2.1 ASTM Standards:E 135 Terminology Relating to Analytical Chemistry forMetals, Ores and Related Materials2E 276 Test Method for Particle Size or Screen Analysis atNo.
6、4 (4.75-mm) Sieve and Finer for Metal-Bearing Oresand Related Materials2E 279 Test Method for Determination of Abrasion Resis-tance of Iron Ore Pellets and Sinter (Tumbler Test)2E 389 Test Method for Particle Size or Screen Analysis atNo. 4 (4.75-mm) Sieve and Coarser for Metal Bearing Oresand Relat
7、ed Materials3E 882 Guide for Accountability and Quality Control in theChemical Analysis Laboratory3E 1072 Test Method for Low Temperature Breakdown ofIron Ores33. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology E 135.3.1.1 nominal sizein sampling, the
8、 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 level.4. Summary of Practice4.1 The precis
9、ion required for the sampling and samplepreparation steps are 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 collected, dried, blended, divided,crushed, pul
10、verized, 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 compositionalspecifications for metal conten
11、t 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 waste disposalprocedures will be followed
12、. 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 and use are dependenton the chemical or ph
13、ysical 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.1This practice is under the jurisdiction of ASTM Committee E01 on AnalyticalChemistry for Metals, Ores, and Related Materials and is
14、the direct responsibility ofSubcommittee E01.02 on Ores, Concentrates, and Related Metallurgical Materials.Current edition approved June 10, 2003. Published September 2003. Originallyapproved in 1982. Last previous edition approved in 1998 as E 877 93 (1998).2Annual Book of ASTM Standards, Vol 03.05
15、.3Discontinued; see 1996 Annual Book of ASTM Standards, Vol 03.06.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Apparatus6.1 Any mechanical sampler is acceptable that either bydesign or comparison, or both (as defined in Annex A
16、1 andAnnex A4) can be shown to take nonbiased increments of atleast 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 acc
17、eptable.6.3 RiffleA stationary sampler comprising an even num-ber of equally sized chutes, adjacent chutes discharging inopposite direction. For use with this practice, there must be aminimum of twelve chutes with an opening width of at least 3times the nominal size.NOTE 1For fine ores (12.5 mm) it
18、is recommended not to exceed 312 timesnominal 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 the
19、re is no chute plugging for aparticular ore type.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 b
20、e of plate, cylinder, or other type that can 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 Requirement
21、s:7.1.1 The characteristics to be determined 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 passi
22、ng thespecified size sieve (in accordance with Methods E 276 andE 389), at 95 % confidence in absolute percentage are as inTable 1.7.2.2 Overall precisions for other characteristics shall beagreed upon between the parties concerned.NOTE 2Nationally or internationally accepted measurement methodsshou
23、ld be used to determine the characteristics 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= estim
24、ated standard deviation of division,sM= 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 = av
25、erage number of secondary increments takenper 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 estim
26、ating swand sDM.7.4 Selection of Sampling 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 W
27、eight of IncrementThe minimum weightof 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
28、, kg,S = nominal size of the ore, cm, andsp 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 gr
29、oss samples orset(s) of subsamples from 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 c
30、haracteris-tics taken from that gross sample.7.6.1 ExampleAssume a gross sample is required for ironanalysis and moisture determination and a separate grossTABLE 1 Overall PrecisionConsignment,tonsIron andMoistureContent,%Specification Size, Cumulative Percent Passing5090 % 90 %100 000 60.3 60.75 %
31、60.075C 60.075 (100-C)A60.75 %20 000 to 100 000 60.4 61.0 % 60.1C 60.1 (100-C) 61.0 %20 000 60.5 62.0 % 60.2C 60.2 (100-C) 62.0 %AC = cumulative passing, %.E877032sample for size distribution and tumble test. Also assume from5.4 the number of increments required to obtain precisiondesired is as foll
32、ows: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 capability (for example,computer controlled). If, however, alte
33、rnative 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 particles must be taken prior to crushing.7.7.2 Samples f
34、or 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 the sample is protected from moisturechange (for example,
35、 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 not be crushed below14-in. sieve (6.3mm) and the minimu
36、m weight of samples used should conformwith Eq 4 (7.6.1). 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 or Annex A2, the number ofprimary increments, as deter
37、mined 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 the sampling cycle is not in phase with thehandling cy
38、cle.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, they shall be takenat equal time intervals with a maximum
39、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 7.4.1.8.5 At this stage, individual test samples are obtaine
40、d 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 of the total divided sample mustbe greater than:W25 S3
41、3 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.The equation is based on the concept that the weight of thelargest piece should be less than 0.5 % of the weight of thedivided sample.8.6.2 Divide
42、 the sample by one of the following procedures:(a) (a) A mechanical sampler operated in accordance withthe guidelines in Annex A1.(b) (b) RifflingUse a pan the same width as the rifflechutes to feed the ore for division. Add increments of ore to thepan and gently agitate the pan over the center of t
43、he 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 clean the equipmentbetween samples.NOTE 5Warning: Use proper dust
44、collection to protect the operatorfrom fine respirable dust particles.(c) Manual Increment Division (Note 6)Mix the entire sample andspread on a flat nonmoisture-absorbing surface so that the sample forms arectangle of uniform thickness. Divide into at least 20 segments of equalarea. With a flat bot
45、tom, square-nose tool, take scoopfuls of approximateequal size from each segment from the full depth of the bed. Thesescoopfuls must have a minimum weight in accordance with Eq 3.Combine the scoopfuls to form the divided sample.NOTE 6Manual increment division, although very efficient for moistor coh
46、esive 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 tosurfaces of sample preparation equipment.8.7.2 Crush, pulverize, an
47、d 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.NOTE 7Warning: Use proper dust collection to protect the operatorfrom fine respirable d
48、ust 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 110C. Where specifications call for a driedsample, it must be dried to constant weight in an oven capableof maintaining a temperature of 105 6 5C. Constant
49、 weight isobtained when an additional hour drying at 105 6 5C does notcause a change greater than 0.05 % weight.NOTE 8The maximum temperature of 110C may be exceeded,provided it is ascertained this will have no effect on any of thecharacteristics to be determined.8.9 CrushingClean and preset the crusher(s) to the sizerequired and slowly feed the sample to the crusher so as not tooverload it. Ore adhering to the crushing surfaces must beadded to the sample by scraping, brushing, or other means.Most ores can be crushed to pass a14-in. (6.3-mm) sieve in
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