1、Designation: E 887 88 (Reapproved 2004)Standard Test Method forSilica in Refuse-Derived Fuel (RDF) and RDF Ash1This standard is issued under the fixed designation E 887; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l
2、ast 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 test method covers the determination of silica inRDF, RDF ash, fly ash, bottom ash, or slag.1.2 The test method i
3、s an acid dehydration gravimetricprocedure and is independent of interferences.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with
4、 its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For hazard state-ment, see Section 6.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reage
5、nt WaterE 791 Test Method for Calculating Refuse-Derived FuelAnalysis Data from As-Determined to Different BasesE 829 Practice for Preparing Refuse-Derived-Fuel (RDF)Laboratory Samples for AnalysisE 830 Test Method for Ash in the Analysis Sample ofRefuse-Derived FuelE 856 Definitions of Terms and Ab
6、breviations Relating toPhysical and Chemical Characteristics of Refuse-DerivedFuel3. Summary of Test Method3.1 Silicon compounds in RDF ash, fly ash, bottom ash, orslag are dissolved by alkali fusion and dehydrated withhydrochloric acid (HCl). Dehydration is completed by ignition,and the silica is v
7、olatilized as silicon tetrafluoride.4. Apparatus4.1 Analytical Balance, capable of weighing to 0.0001 g.4.2 Muffle FurnaceThe furnace shall have an operatingtemperature of up to 1200C.4.3 Hot Plate or Steam Bath.4.4 Platinum Crucibles, 35 to 85-mL capacity.4.5 Graphite Crucibles, 35 to 85-mL capacit
8、y.4.6 Fused Quartz Dishes, 35 to 85-mL capacity.5. Reagents and Materials5.1 Purity of ReagentsReagent grade chemicals shall beused in this test. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American C
9、hemical Societywhere such specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.5.2 Purity of WaterUnless otherwise indicated, referenceto water shall
10、 be understood to mean at least Type III reagentwater conforming to Specification D 1193.5.3 Sodium Carbonate (Na2CO3), anhydrous powder.5.4 Hydrochloric Acid (HCl), concentrated, sp gr 1.19.5.5 Hydrochloric Acid (1 + 3), Mix 1 volume of concen-trated HCl with 3 volumes of water.5.6 Hydrochloric Aci
11、d (1 + 1)Mix 1 volume of concen-trated HCl with 1 volume of water.5.7 Hydrochloric Acid (1 + 99)Mix 1 volume of concen-trated HCl with 99 volumes of water.5.8 Sulfuric Acid (1 + 1)Mix 1 volume of concentratedsulfuric acid (H2SO4, sp gr 1.84) with 1 volume of water.5.9 Hydrofluric Acid (HF), concentr
12、ated 48 to 51 %.6. Hazards6.1 Due to the origins of RDF in municipal waste, commonsense dictates that precautions should be observed whenconducting tests on the samples. Recommended hygienicpractices include use of gloves when handling RDF; wearingdust masks (NIOSH-approved type), especially while m
13、illingRDF samples; conducting tests under negative pressure hoodswhen possible; and washing hands before eating or smoking.1This test method is under the jurisdiction of ASTM Committee D34 on WasteManagement and is the direct responsibility of Subcommittee D34.03.02 onMunicipal Recovery and Reuse.Cu
14、rrent edition approved March 25, 1988. Published May 1988. Originallypublished as E 887 82. Last previous edition E 887 82.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, re
15、fer to the standards Document Summary page onthe ASTM website.3“Reagent Chemicals, American Chemical Society Specifications,” Am. Chemi-cal Soc., Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see “Analar Standards for Laboratory U.K.Chemicals,
16、” BDH Ltd., Poole, Dorset, and the “United States Pharmacopeia.”1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Sampling7.1 Refuse-Derived Fuel (RDF):NOTE 1ASTM Subcommittee E38.01 is currently in the process ofdeveloping procedur
17、es for sampling RDF.7.1.1 RDF products are frequently nonhomogeneous. Forthis reason, significant care should be exercised to obtain arepresentative laboratory sample from the RDF lot to becharacterized.7.1.2 The sampling method for these procedures should bebased on agreement between involved parti
18、es.7.1.3 The laboratory sample must be air-dried and particlesize reduced to pass a 0.5-mm screen for analysis. Thisprocedure must be performed carefully to preserve the sam-ples representative characteristics (other than particle size)while preparing the analysis sample to be used in this proce-dur
19、e (see Practice E 829).7.2 Refuse-Derived Fuel Ash, Fly Ash, Bottom Ash, orSlagThe method of sampling for this procedure should bebased on agreement between involved parties.8. Sample Preparation8.1 Refuse-Derived Fuel:8.1.1 Weigh accurately 30 to 50 g of RDF analysis sampleas prepared in 7.16.1 int
20、o a conditioned and preweighed fusedquartz dish.8.1.2 Spread out the analysis sample of RDF in a layer notover 38.1 mm (112 in.) in depth.8.1.3 Place the dish in the muffle at a low temperature (notgreater than 100C) and gradually heat to redness at such a rateas to avoid mechanical loss from too ra
21、pid expulsion of volatilematter.8.1.4 Complete the conversion to ash at a temperature of800 to 900C (1470 to 1650F).8.1.5 Cool in a desiccator and stir the ash to ensurehomogeneity of particle sizes. Be careful not to lose any ashfrom the dish during this stirring.8.1.6 Spread the ash in a thin laye
22、r in the dish, and ignite ina stream of oxygen for 112 h at 800 to 850C (1470 to 1560F)to ensure complete and uniform oxidation of the ash.8.1.7 Cool the ash to room temperature in a desiccator.8.1.8 Weigh the dish and the ash.8.1.9 Calculate the percent ash as follows:% Ash 5 C 2 A!/B 2 A! 3 100 (1
23、)where:A = weight of fused quartz, g,B = weight of fused quartz dish and sample, g, andC = weight of fused quartz dish and ash, g.8.2 Refuse-Derived Fuel Ash, Fly Ash, Bottom Ash, or Slag:8.2.1 Prepare the RDF ash, fly ash, bottom ash, or slag bygrinding the sample in an agate mortar to a particle s
24、ize to passa No. 200 (75-m) sieve.8.2.2 Weigh accurately 6 to 10 g of RDF ash, fly ash, bottomash, or slag as prepared in 8.2.1 into a conditioned preweighedfused quartz dish.8.2.3 Spread out the analysis sample of the ash to beanalyzed in a layer not over 6.4 mm (14 in.) in depth.8.2.4 Place the di
25、sh in the muffle at a low temperature (notgreater than 100C), and gradually heat to redness at such arate as to avoid mechanical loss from too rapid expulsion ofvolatile matter.8.2.5 Complete the conversion to ash at a temperature of800 to 900C (1470 to 1659F).8.2.6 Cool in a desiccator and stir the
26、 ash to ensurehomogeneity of particle sizes. Be careful not to lose any ashfrom the dish during this stirring.8.2.7 Spread the ash in a thin layer in the dish and ignite ina stream of oxygen for 112 h at 800 to 850C (1470 to 1560F)to ensure complete and uniform oxidation of the ash.8.2.8 Cool the as
27、h to room temperature in a desiccator.8.2.9 Weigh the dish and the ash.8.2.10 Calculate the percent residue after ignition as fol-lows:% Residue after ignition 5 F 2 D!/E 2 D! 3 100 (2)where:D = weight of fused quartz dish, g,E = weight of fused quartz dish and sample, of RDF ash,fly ash, bottom ash
28、 or slag, g, andF = weight of fused quartz dish and residue after ignition ofRDF ash, fly ash, bottom ash, or slag, g.9. Procedure9.1 Sample Fusion:9.1.1 Weigh accurately 0.010 to 0.100 g of the preparedRDF ash as prepared in 8.1 or the residue of RDF ash, fly ash,bottom ash, or slag as prepared in
29、8.2 into a platinum orgraphite crucible.9.1.2 Add 1.0 g of Na2CO3. Mix the ash and Na2CO3well,then add an additional 0.5 g of Na2CO3to cover the mixture.9.1.3 Place the crucible into a clean silica or refractory tray,and place in a muffle furnace preheated to 1000C and maintainuntil the mass is quie
30、scent (about 45 min).9.1.4 Set the crucible aside to cool.9.1.5 Rinse off the outside of the crucible, and place it on itsside in a 300-mL casserole or beaker about one-third full ofwater. Warm and stir until the cake disintegrates and can beeasily removed.9.1.6 By means of platinum tipped tongs, li
31、ft the crucibleout of the liquid, rinsing it thoroughly with water followed byrinsing with dilute hydrochloric acid (HCl, 1 + 3); adding therinse to the casserole or beaker.9.2 Acid Dehydration:9.2.1 Very slowly and cautiously add 20 mL of concentratedhydrochloric acid (HCl, sp gr 1.19) to the cover
32、ed casserole orbeaker (see Note 2). Remove the cover and rinse. If any grittyparticles are present, the fusion is incomplete and must berepeated, using a new sample and a larger amount of Na2CO3.NOTE 2This solution will tend to “creep” over the rim of the casseroleunless the rim is kept hot and dry.
33、 This can be accomplished by applyingheat from above by means of infrared lamps.9.2.2 Evaporate the solution to dryness on a steam bath.9.2.3 Without heating the residue any further, treat it with 5to 10 mL of HCl (concentrated), wait at least 2 min, then addan equal amount of water.E 887 88 (2004)2
34、9.2.4 Cover the casserole or beaker, and digest for 10 minon the steam bath or hot plate.9.2.5 Dilute the solution with an equal volume of hot water,immediately filter through medium-textured ashless paper, andwash the residue thoroughly with hot HCl (1 + 99), then withhot water.9.2.6 Reserve the re
35、sidue.9.2.7 Again, evaporate the filtrate to dryness and bake theresidue in an oven for1hat105to110C.9.2.8 Cool, add 10 to 15 mL HCl (1 + 1) and digest on thesteam bath or hot plate for 10 min.9.2.9 Dilute with an equal volume of water, filter immedi-ately on a fresh filter paper, and wash the small
36、 amount ofresidue thoroughly with hot HCl (1 + 99), then with hot water.9.2.10 Transfer the papers containing the residues (from9.2.6 and 9.2.9) to a weighed conditioned platinum crucible.9.2.11 Dry and ignite the papers, first at a low heat until thecarbon of the filter paper is completely consumed
37、 withoutflaming, and finally ignite at 1100 to 1200C until the weightbecomes constant. Record weight of residue after ignition.9.3 Volatilization of Silicon Tetrafluoride:9.3.1 Treat the silica (SiO2) thus obtained, which will con-tain impurities, in the crucible with 0.5 to 1 mL of water, 2drops of
38、 H2SO4(1 + 1) and 10 mL of HF.9.3.2 Cautiously evaporate to dryness on a hot plate or hotsand bath.9.3.3 Finally, ignite the small residue at 1050 to 1100C(1922 to 2012F) for 5 min.9.3.4 Cool in a desiccator and weigh.9.3.5 The difference between this weight and the weightpreviously obtained in 9.2.
39、11 represents the amount of SiO2.9.4 BlankMake a blank determination, following thesame procedures as used in 9.1.2 through 9.3.5 using the sameamounts of reagents and correct the obtained in the analysisaccordingly.10. Calculation10.1 Calculate the concentration of SiO2as follows:10.1.1 Percent SiO
40、2on prepared sample as used in 9.1.1.% SiO25 W12 W2! 2 W32 W4!/W53 100 (3)where:W1= weight of residue after first ignition as in 9.2.11,g,W2= weight of blank after first ignition, g,W3= weight of residue after treatment with HF and secondignition as in 9.3.4,g,W4= weight of blank after treatment wit
41、h HF and secondignition, g, andW5= weight of sample of prepared RDF, RDF ash, fly ash,bottom ash, or slag as used in 9.1.1,g.10.1.2 Percent SiO2in RDF (6.1).% SiO2in RDF 5 G 3 H!/100! (4)where:G = ash as found in 8.1.9, %, andH = SiO2as found in 10.1.1,%.10.1.3 Percent SiO2in RDF ash, fly ash, botto
42、m ash, or slag(8.2).% SiO2in RDF Ash, fly ash, bottom ash, or slag 5 I 3 H!/100!(5)where:I = residue after ignition as found in 8.2.10, %, andH = SiO2as found in 10.1.1,%.See Method E 791 for procedures to convert values to otherbases.11. Precision and Bias11.1 Precision and bias statements cannot b
43、e made at thistime for the measurement of SiO2by this test method.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any s
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46、a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).E 887 88 (2004)3
