1、Designation: D 1857 04Standard Test Method forFusibility of Coal and Coke Ash1This standard is issued under the fixed designation D 1857; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parent
2、heses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method covers the observation of the tempera-tures at which
3、 triangular pyramids (cones) prepared from coaland coke ash attain and pass through certain defined stages offusing and flow when heated at a specified rate in controlled,mildly reducing, and where desired, oxidizing atmospheres.1.2 The test method is empirical, and strict observance ofthe requireme
4、nts and conditions is necessary to obtain repro-ducible temperatures and enable different laboratories to obtainconcordant results.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 addres
5、s 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 health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 2013 Method of
6、 Preparing Coal Samples for AnalysisD 3174 Test Method forAsh in theAnalysis Sample of Coaland Coke from Coal3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 The critical temperature points to be observed are asfollows, denoting the atmosphere used:3.1.2 fluid temperature, FTth
7、e temperature at which thefused mass has spread out in a nearly flat layer with amaximum height of 1.6 mm (116 in.) as shown by the fifthcone, FT, in Fig. 1.3.1.3 hemispherical temperature, HTthe temperature atwhich the cone has fused down to a hemispherical lump atwhich point the height is one half
8、 the width of the base asshown by the fourth cone, HT, in Fig. 1.3.1.4 initial deformation temperature, ITthe temperatureat which the first rounding of the apex of the cone occurs.Shrinkage or warping of the cone ignored if the tip remainssharp. In Fig. 1, the first cone shown is an unheated one; th
9、esecond cone IT is a typical cone at the initial deformation stage.3.1.5 softening temperature, STthe temperature at whichthe cone has fused down to a spherical lump in which theheight is equal to the width at the base as shown by the thirdcone, ST, in Fig. 1.4. Significance and Use4.1 Design of mos
10、t coal combustion and coal conversionequipment anticipates that the ash either remain solid orassume some degree of fluidity, depending on the particulardesign.Ash fusibility temperatures predict whether the ash willperform properly in the process for which the coal was chosen.5. Apparatus and Mater
11、ials5.1 FurnaceAny gas-fired or electric furnace conformingto the following requirements may be used:5.1.1 Capable of maintaining a uniform temperature zone inwhich to heat the ash cones. This zone shall be such that thedifference in the melting point of 12.7-mm (12-in.) pieces ofpure gold wire when
12、 mounted in place of the ash cones on thecone support shall be not greater than 11C (20F) in areducing atmosphere test run.5.1.2 Capable of maintaining the desired atmosphere sur-rounding the cones during heating. The composition of theatmosphere, reducing or oxidizing, shall be maintained withinthe
13、 limits specified in Section 6. The desired atmosphere in thegas-fired furnace surrounding the cones shall be obtained byregulation of the ratio of gas to air in the combustion mixture.The desired atmosphere in the electric furnace shall be ob-tained by means of gases introduced into the heating cha
14、mber.1This test method is under the jurisdiction of ASTM Committee D05 on Coaland Coke and is the direct responsibility of D05.21 on Methods of Analysis.Current edition approved July 1, 2004. Published July 2004. Originally approved1961. Last previous edition approved 2003 as D 1857 03.2For referenc
15、ed ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.FIG. 1 Critical Temperature Points1Copyright ASTM International, 100 Barr
16、Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.The muffle shall be gas impervious, free from cracks, and theclosure plug tight-fitting. The gas supply tube shall be sealed tothe back wall of the preheating chamber and shall not extend tothe front of the preheating chamber
17、 against the perforatedbaffle.5.1.3 Capable of regulation so that the rate of temperaturerise shall be 8 6 3C (15 6 5F)/min.5.1.4 Providing means of observing the ash cones during theheating. Observation on the same horizontal plane as thecone-support surface shall be possible.5.2 Cone MoldA commerc
18、ially available cone mold asshown in Fig. 2. The cone shall be 19 mm (34 in.) in height and6.4 mm (14 in.) in width at each side of the base which is anequilateral triangle. A steel spatula with a pointed tip, groundoff to fit the cone depression in the mold, is suitable forremoval of the ash cone.5
19、.3 Optical Pyrometer or Thermocouple, for temperaturemeasurements, conforming to the following requirements:5.3.1 Optical PyrometerAn optical pyrometer of the dis-appearing filament type shall be used. The instrument shallhave been calibrated to be accurate within 11C (20F) up to1400C (2550F) and wi
20、thin 16C (30F) from 1400 to 1600C(2550 to 2900F) (Note 1). The pyrometer filament shall besighted on the cones until the softening point temperature C(Fig. 1) has been passed, and then sighted on the cone support.The pyrometer shall have readable graduations not larger than5.5C (10F).NOTE 1The pyrom
21、eter equipment shall be standardized periodicallyby a suitably equipped standardizing laboratory such as that of theNational Bureau of Standards, or checked periodically against equipmentcertified by the Bureau of Standards.5.3.2 ThermocoupleA thermocouple of platinum andplatinum-rhodium, protected
22、from the furnace gases by aglazed porcelain sheath, shall be used with a high-resistancemillivoltmeter or potentiometer accurate and readable to within5.5C (10F). The sheath shall be sealed to the furnace wall byalundum cement. The hot junction of the thermocouple shalltouch the end of the sheath an
23、d shall be located in the center ofthe muffle and immediately to the rear of the cones. Thethermocouple protective sheath shall be checked periodicallyfor cracks. The thermocouple and its meter shall meet therequirements of Section 9. The potentiometer or millivoltmetershall be so located or adequat
24、ely shielded as to prevent radiantand convection heating of the cold junction. The room tem-perature compensator shall be adjusted to the existing tempera-ture.5.4 Ash-Cone Refractory SupportThe ash cones shall bemounted on a refractory base composed of a mixture of equalparts by weight of kaolin an
25、d alumina conforming to thefollowing requirements:5.4.1 KaolinNF-grade powder passing a 75-m (No. 200)sieve.5.4.2 Aluminum OxideReagent grade ignited powderpassing a 150-m (No. 100) sieve.5.5 Refractory Support MoldA mold with flat top andbottom surfaces to provide a refractory support of suitableth
26、ickness to minimize warping. A sidemold not over 6.4 mm(14 in.) high of any convenient shape, placed on an iron plateso that the top surface of the refractory mix can be struck offflat and parallel to the base by means of a straightedge, issatisfactory. For electric furnace use, legs not over18 in.
27、(3mm) long may be provided on the corners of the cone supportby suitable holes bored in the iron base plate of the mold.5.6 Gold Wire30.51-mm diameter (twenty-four gage) orlarger round wire of 99.98 % purity, but drawn from metal of99.99 % purity, and having a melting point of 1063C(1945F).5.7 Nicke
28、l Wire40.51-mm diameter (twenty-four gage) orlarger round wire of CP nickel, 99.98 % pure, fully annealed,and having a melting point of 1452C (2645F).6. Test Atmosphere6.1 Gas-Fired Furnace:6.1.1 Reducing Atmosphere TestA mildly reducing atmo-sphere surrounding the cones shall be maintained during t
29、hetest in the gas-fired furnace. Hydrogen, hydrocarbons, andcarbon monoxide shall be considered as reducing gases;oxygen, carbon dioxide, and water vapor shall be considered asoxidizing gases. Nitrogen is inert. The ratio by volume ofreducing gases to oxidizing gases in the atmosphere shall bebetwee
30、n the limits of 20 to 80 and 80 to 20,5that is, on anitrogen-free basis, the total amount of reducing gases presentshall be between the limits of 20 and 80 volume %. A flame152 to 203 mm (6 to 8 in.) in height and tinged with yellow3Gold wire of this purity can be purchased from the Baker Dental Div
31、ision ofEngelhard Industries, Inc., 850 Passaic Ave., East Newark, NJ 07029 or from LeicoIndustries, Inc., 250 W. 57th St., New York, NY 10019.4Nickel wire of this purity can be purchased with the additional specification ofhaving a minimum coefficient of resistance for 0 to 100C of 0.006 73 V/VC, f
32、romLeico Industries, Inc., 250 W. 57th St., New York, NY 10019.5For information concerning the effect of various atmospheres, see U.S. Bureauof Mines Bulletin 129, 1918.Inch-poundUnits,in.SI Units,mm14 6.434 19.1112 38.12 50.23 76.2FIG. 2 Brass Cone MoldD1857042above the furnace outlet has been foun
33、d to provide anatmosphere within the specified limits.6.1.2 Oxidizing Atmosphere TestAn atmosphere contain-ing a minimum amount of reducing gases shall be maintainedsurrounding the cones during the test in the gas-fired furnace.On a nitrogen-free basis, the volume of reducing gases presentin the atm
34、osphere shall not exceed volume 10 %. Combustionwith the maximum possible quantity of air with preservation ofthe specified rate of temperature increase has been found toprovide an atmosphere within the specified limits. A com-pletely blue flame, not over 50 mm (2 in.) in height above theoutlet at t
35、he beginning of the test, provides the desiredatmosphere; and, by regulation of the combustion gas-air ratio,the specified atmosphere and temperature rise can be main-tained.6.2 Electric Furnace:6.2.1 Reducing Atmosphere TestA regulated flow of gasof the nominal composition, 60 % carbon monoxide and
36、 40 65 volume % carbon dioxide,6shall be maintained in the heatingchamber throughout the test (Note 2) in the electric furnace.The gas stream shall be regulated by any convenient means toprovide a measured flow of 1.3 to 1.5 furnace volumes perminute.6.2.2 Oxidizing Atmosphere TestA regulated stream
37、 of airshall be maintained throughout the test in the electric furnace.The gas stream shall be regulated by any convenient means toprovide a measured flow of 1.3 to 1.5 furnace volumes perminute.NOTE 2Before using new cylinders of CO/CO2reducing gas, thecontents should be mixed according to the gas
38、manufacturers recommen-dations. To assure that the gas remains mixed, the temperature of thecylinder contents should be maintained above the critical temperature atwhich CO2can liquify and separate.7. Preparation of Ash7.1 Use coal or coke passing a 250-m (No. 60) sieveprepared in accordance with Me
39、thod D 2013, to obtain the ashby incineration in a well-ventilated muffle furnace. The quan-tity of coal or coke required will vary with the ash content;usually 3 to 5 g of ash will be sufficient for cones for severalcheck determinations, if necessary. Spread out the coal or cokein a layer not over
40、6.4 mm (14 in.) in depth in a fireclay orporcelain roasting dish. Place the dish in the cold muffle or onthe hearth at a low temperature and gradually heat to redness atsuch a rate as to avoid mechanical loss from too rapidexpulsion of volatile matter (Note 3). Complete the conversionto ash at a tem
41、perature of 800 to 900C (1470 to 1650F).Transfer the ash to an agate mortar (Note 4) and grind it so thatit will pass a 75-m (No. 200) sieve. Then spread the ash in athin layer in a fireclay, silica, or porcelain dish and ignite it ina stream of oxygen for 112 h at 800 to 850C (1470 to 1560F)to ensu
42、re complete and uniform oxidation of the ash. Any tubeor muffle-type furnace which, when supplied with an oxygenflow of not less than one furnace volume in 5 min, willmaintain a highly oxidizing atmosphere and will be suitable.NOTE 3A heating rate conforming to that used for the ash determi-nation s
43、pecified in Section 7 of Test Method D 3174 is satisfactory.NOTE 4Amechanical agate mortar grinder will save time where manydeterminations are made. An iron mortar or pestle must not be used.8. Preparation of Cones8.1 Thoroughly mix the ignited ash in a mechanical mixeror on a sheet of glazed paper
44、or oil cloth by raising first onecorner to roll the ash over and then raising each of the othercorners in rotation in the same manner until each corner hasbeen raised five times or more.8.2 Take sufficient ash for the number of cones desired fromvarious parts of the bulk ash. Moisten the ash with a
45、few dropsof a clear, filtered (if necessary) 10 % solution of dextrincontaining 0.1 % salicylic acid as a preservative and work itinto a stiff plastic mass with a spatula. Press the plastic materialfirmly with a spatula into the cone mold to form the triangularpyramids. Strike off the exposed surfac
46、es of the materialsmooth and remove the cones from the mold by applyingpressure at the base with a suitably pointed spatula. Previouscoating of the mold with a thin layer of petroleum jelly, thinnedwith kerosene (if necessary), aids in preventing adherence ofthe cones to the mold and in providing th
47、e sharp point andedges desired in the cone. With certain coal ashes, cones withsharp points and edges can be obtained using distilled water inplace of the dextrin solution and without the use of petroleumjelly.8.3 Place the cones in a suitable location to dry sufficientlyto permit handling without d
48、eformation. Mount the dried conevertically on a freshly prepared refractory base. Moisten aportion of the well-mixed kaolin-alumina mixture with theminimum amount of water to make a workable, but stiff, plasticmass, and firmly press it into the support mold. Strike off thesurface of the mass flat an
49、d smooth with a steel spatula,moistening with one or two drops of water if necessary toobtain a smooth surface. A number of cones may be mountedon one base. Make shallow triangular depressions, not over 0.8mm (132 in.) in depth, with a triangular file ground to thecorrect size to produce a depression to fit the base of the cone,and locate the cones sufficiently distant from adjacent cones sothat no merging of the fusing material of the cones shall occurduring the test. Mount the cones vertically in the depressionswhile
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