1、Designation: E 1506 97 (Reapproved 2003)Standard Test Methods forAnalysis of Acid-Grade Calcium Fluoride (Fluorspar)1This standard is issued under the fixed designation E 1506; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar of last 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 These test methods cover the chemical analyses ofacid-grade calcium fluoride (fluorspar). These test methodsapp
3、ear in the following sections:SectionsVolatiles as Moisture 6-13Silica 14-22Assay as Calcium Fluoride (CaF2) 23-32Soluble Chloride as NaC1 33-50Calcium Carbonate 51-59Phosphorus 60-69Arsenic 70-78Mixed Oxides (R2O3) 79-87Sulfide Sulfur 88-961.2 The values stated in SI units are to be regarded as the
4、standard. The values given in parentheses are for informationonly.1.3 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 health practices and determine the app
5、lica-bility of regulatory limitations prior to use.1.4 Review the current Material Safety Data Sheet (MSDS)for each chemical used in this standard for detailed informationconcerning toxicity, first-aid procedures, handling, and safetyprecautions.2. Referenced Documents2.1 ASTM Standards:D 1193 Speci
6、fication for Reagent Water2E 180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial Chemicals3E 300 Practice for Sampling Industrial Chemicals43. Significance and Use3.1 Calcium fluoride is available in nature in various formsand purities. A major use for it
7、 is in the manufacture ofhydrofluoric acid. The test methods listed in 1.1 provideprocedures for analyzing calcium fluoride to determinewhether it is suitable for this use.4. Reagents4.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended t
8、hatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.5Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without le
9、ssening theaccuracy of the determination.4.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean Type II or Type IIIreagent water conforming to Specification D 1193.5. Sampling5.1 Sampling of calcium fluoride is not within the scope ofthese test methods. See the
10、 appropriate sections of PracticeE 300 for sampling procedures.VOLATILES AS MOISTURE6. Scope6.1 This test method covers the determination of volatiles aspercent moisture.7. Summary of Test Method7.1 The sample is dried in an air oven at 105 to 110C, andthe weight loss is calculated as percent moistu
11、re.8. Apparatus8.1 Top-Loading Balance, capable of weighing 1000 g tothe nearest 0.01 g.8.2 Sample Pan, stainless steel or borosilicate glass, 152 by152 by 51 mm (6 by 6 by 2 in.) deep.8.3 Cooling Rack, wood or metal, able to allow circulationof air around the entire sample pan (for example, a “bake
12、rsrack”).1These test methods are under the jurisdiction of ASTM Committee E15 onIndustrial and Specialty Chemicalsand are the direct responsibility of SubcommitteeE15.02 on Product Standards.Current edition approved Apr. 10, 2003. Published May 2003. Originallyapproved in 1994. Last previous edition
13、 approved in 1997 as E 1506 97.2Annual Book of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 15.05.4Discontinued. See 2000 Annual Book of ASTM Standards, Vol 15.05.5Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions
14、on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1Copyright ASTM International, 100 Ba
15、rr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.8.4 Forced Air Oven, capable of maintaining temperaturesof 105 to 110C.9. Hazards9.1 See 1.3 and 1.4.10. Procedure10.1 Tare a clean, dry sample pan to the nearest 0.01 g.10.2 Add approximately 1000 g of representative samp
16、le tothe pan and spread evenly. Wipe all external surfaces of the panfree of sample. Weigh again to the nearest 0.01 g.10.3 Place the pan containing the sample in an air oven at105 to 110C for a minimum of 12 h.10.4 Remove the pan from the oven and place on a coolingrack for 1 h.10.5 Weigh the coole
17、d pan to the nearest 0.01 g.10.6 Return the pan to the cooling rack and cool for anadditional 30 min. Then reweigh the pan to the nearest 0.01 g.10.7 Repeat 11.6 until consecutive weights agree within0.05 g.10.8 Once a consistent weight has been obtained, dump thesample on a flat, dry surface and sp
18、read it with a spatula. If thefluorspar is dry, it will appear dusty, powdery, and flour-like inconsistency. If the fluorspar does not appear as such, repeat theanalysis using fresh sample.11. Calculation11.1 Calculate percent volatiles as moisture as follows:volatiles as moisture, weight % 5B 2 C!
19、3 100B 2 A!(1)where:A = weight of empty pan, g (10.1),B = weight of pan plus sample before drying, g (10.2), andC = weight of pan plus sample after drying to consistentweight, g (10.7).12. Report12.1 Report the percent volatiles as moisture to the nearest0.01 %.13. Precision and Bias13.1 PrecisionTh
20、e following criteria should be used forjudging the acceptability of results (see Note 1):13.1.1 Repeatability (Single Analyst)The standard devia-tion for a single determination has been estimated to be thevalue shown in Table 1 at the indicated degrees of freedom.The 95 % limit for the difference be
21、tween two such runs is thevalue shown in Table 1.13.1.2 Laboratory Precision (Within-Laboratory, Between-Days)The standard deviation of results (each the average ofduplicates) obtained by the same analyst on different days hasbeen estimated to be the value shown in Table 2 at the indicateddegrees of
22、 freedom. The 95 % limit for the difference betweentwo such averages is the value shown in Table 2.13.1.3 Reproducibility (Multilaboratory)The standard de-viation of results (each the average of duplicates) obtained byanalysts in different laboratories has been estimated to be thevalue shown in Tabl
23、e 2 at the indicated degrees of freedom.The 95 % limit for the difference between two such averages isthe value shown in Table 2.NOTE 1These precision estimates are based on an interlaboratorystudy performed in 1992 in which samples of fluorspar from two lots, onecontaining about 6 % volatiles as mo
24、isture and the other about 9 %volatiles as moisture, were each analyzed in duplicate by one analyst oneach of two days in each of ten laboratories for a total of 120determinations.6Practice E 180 was used in developing these precisionestimates.13.2 BiasThe bias of this test method has not beendeterm
25、ined due to the unavailability of suitable referencematerials.SILICA14. Scope14.1 This test method covers the determination of percentsilica.15. Summary of Test Method15.1 The sample is treated with 10 % acetic acid to removecarbonates and soluble salts, the residue is ignited in a 650Cmuffle furnac
26、e, treated with 48 % hydrofluoric acid (HF), andthen heated again at 650C. The weight loss after the HFtreatment is calculated as percent silica.16. Apparatus16.1 Analytical Balance, capable of weighing to the nearest0.1 mg.16.2 Beaker, 150-mL glass, unscratched, and watchglasscover.16.3 Graduated C
27、ylinder, 25-mL glass.16.4 Graduated Cylinder, 10-mL polypropylene.16.5 Platinum Crucible, 30-mL capacity with lid.16.6 Platinum Wire,4cmby2mm.16.7 Stirring Rod, borosilicate glass, unscratched.16.8 Muffle Furnace, capable of maintaining a temperatureof 650 6 10C or higher.16.9 Desiccator, with desic
28、cant.16.10 Steam Bath.16.11 Glass Filter Funnel.16.12 Bunsen Burner, ringstand, ring, and heating mesh.6Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: E151027.TABLE 1 Volatiles as Moisture Checking Limits for DuplicatesVolatile
29、s Level,%StandardDeviationDegrees ofFreedom95 % Limit, %Absolute6 0.0257 18 0.0729 0.0822 18 0.230TABLE 2 Volatiles as MoistureVolatilesLevel,%Repeatability ReproducibilityStandardDeviationDegrees ofFreedom95 %Limit, %AbsoluteStandardDeviationDegrees ofFreedom95 %Limit,%Absolute6 0.0238 9 0.067 0.08
30、07 8 0.2269 0.0666 9 0.186 0.0865 8 0.242E 1506 97 (2003)216.13 Disposable Pipets.16.14 Mortar and Pestle, 102-mm (4-in.) diameter, agate.16.15 Tongs, platinum-tipped.17. Reagents17.1 Acetic Acid Solution (100 mL/L)Dilute 10 mL ofglacial acetic acid to 100 mL with water; mix well.17.2 Hydrofluoric A
31、cid (HF), 48 %.17.3 Ashless Cellulose Filter Aid, Whatman acceleratorpowder,7or equivalent.17.4 Filter Paper, 9-cm diameter, low-ash, acid-washed,medium-porosity, able to retain 8-m particles.17.5 Filter Paper, 9-cm diameter, low-ash, acid-washed,fine-porosity, able to retain 2.5-m particles.17.6 Et
32、hanol, pure or denatured.17.7 Filter Pulp Slurry (40 g/L)Slurry 10 g of cellulosefilter aid with 250 mL of water.18. Hazards18.1 See 1.3 and 1.4.19. Procedure19.1 Transfer 8 to 10 g of sample (previously dried toconstant weight at 105 to 110C) into a mortar. Grind with apestle until the particle siz
33、e is 100 to 500 mesh.19.2 Weigh 1.0 g of the ground sample to the nearest 0.0001g, and transfer it to a 150-mL beaker.19.3 Wet the sample with 1 mL of ethanol, then add 15 mLof 10 % acetic acid to the beaker.19.4 Add a glass stirring rod to the beaker, cover with awatchglass, and place on a steam ba
34、th.19.5 Heat for 30 6 1 min, stirring every 5 min.19.6 Remove from the steam bath, add 5 mL of filter pulpslurry to the beaker, cover, and allow to sit for approximately12 h.19.7 Gravity filter the solution through medium-porosityfilter paper.19.8 Rinse the beaker several times with minimal portions
35、of hot water (total wash water approximately 35 mL), filteringeach wash through the same filter paper. Save the filtrate for thedetermination of Mixed Oxides (Section 79).19.9 Wipe the beaker clean with one fourth of a fine-porosity filter paper, and transfer the wipe paper and the filterpaper with
36、the residue into a 30-mL platinum crucible.19.10 Place a platinum wire across the top of the platinumcrucible. Rest the crucible lid on the wire and place the crucibleinto a cool muffle furnace.19.11 Heat the furnace slowly (1-h cycle) to 650 6 10C.Once the temperature has reached 650C, check the cr
37、ucibleevery 10 min until the paper is entirely burned off.19.12 Cool the crucible to room temperature in a desiccator,then weigh the crucible, cover, and residue to 0.0001 g.19.13 Using a 10-mL polypropylene graduate cylinder,carefully pour 3 mL of 48 % HF into the crucible.19.14 Gently heat the cru
38、cible over a Bunsen burner in ahood until dry (see Note 2).NOTE 2The solution must be heated below boiling. Excess heat willcause erratic results. If unable to control heating using a bunsen burner,heat the solution on a hot plate at 60C or below. Evaporation of the 6 mLof HF used in this procedure
39、should take approximately 2 h.19.15 Cool the crucible, then repeat 19.13 and 19.14.19.16 Cover the crucible with a platinum lid; then carefullyplace it into a muffle furnace maintained at 650 6 10C.19.17 Heat the crucible for 5 min; then place it into adesiccator to cool.19.18 Weigh the crucible, co
40、ver, and residue to 0.0001 g.20. Calculation20.1 Calculate percent silica as follows:silica, weight % 5B 2 C! 3 100A(2)where:A = weight of sample, g (19.2),B = weight of crucible, cover, and residue before HFtreatment, g (19.12), andC = weight of crucible, cover, and residue after HF treat-ment, g (
41、19.18).21. Report21.1 Report the percent silica to the nearest 0.01 %.22. Precision and Bias22.1 PrecisionThe following criteria should be used forjudging the acceptability of results (see Note 3):22.1.1 Repeatability (Single Analyst)The standard devia-tion for a single determination has been estima
42、ted to be0.0319 % absolute at 50 df. The 95 % limit for the differencebetween two such runs is 0.09 % absolute.22.1.2 Laboratory Precision (Within-Laboratory, Between-Days)The standard deviation of results (each the average ofduplicates) obtained by the same analyst on different days hasbeen estimat
43、ed to be 0.0362 % absolute at 25 df. The 95 %limit for the difference between two such averages is 0.10 %absolute.22.1.3 Reproducibility (Multilaboratory)The standard de-viation of results (each the average of duplicates) obtained byanalysts in different laboratories has been estimated to be0.0529 %
44、 absolute at 11 df. The 95 % limit for the differencebetween two such averages is 0.15 % absolute.NOTE 3These precision estimates are based on an interlaboratorystudy performed in 1992 in which samples of fluorspar from two lots, onecontaining about 0.5 % silica and the other about 1 % silica, were
45、eachanalyzed in duplicate on each of two days by one analyst in each of 14laboratories for a total of 112 determinations.6Practice E 180 was used indeveloping these precision estimates.22.2 BiasThe bias of this test method has not beendetermined due to the unavailability of suitable referencemateria
46、ls.7Available from Whatman LabSales, P.O. Box 1359, Hillsboro, OR, 97123-9981.E 1506 97 (2003)3ASSAY AS CALCIUM FLUORIDE (CaF2)23. Scope23.1 This test method covers the determination of assay aspercent calcium fluoride (CaF2).24. Summary of Test Method24.1 The residue remaining after the determinati
47、on of silica(see 19.18) is treated with H2SO4, dried, then dissolved in HCl.Ammonium oxalate is added to the HCl solution to precipitatecalcium oxalate, then the precipitate is dried and weighed.Percent CaF2is calculated from the weight of the calciumoxalate collected.25. Interferences25.1 Iron caus
48、es a positive interference. If iron is suspectedto be present, its effect can be minimized by adding 1 mL ofconcentrated HNO3to the solution described in 29.8 beforeboiling.25.2 Strontium precipitates, as the oxalate, along withcalcium oxalate to produce erroneously high results.25.3 A small amount
49、of CaF2is lost in the acetic acidtreatment used in 19.3, resulting in an erroneously low result.To correct for this loss, the term 0.15 is included in thecalculation in 30.1.26. Apparatus26.1 Analytical Balance, capable of weighing to the nearest0.1 mg.26.2 Beakers, borosilicate glass, 800-mL, 400-mL, andwatchglass covers.26.3 Graduated Cylinders, borosilicate glass, 10-mL, 25-mL.26.4 Platinum Crucible, 30-mL capacity with lid.26.5 Platinum Wire,4cmby2mm.26.6 Stirring Rod, borosilicate glass.26.7 Muffle Furnace, capable of maintaining a temperatureo
