1、Designation: C1843 16Standard Test Method forDetermining Moisture Content in Uranium-Ore Concentrate1This standard is issued under the fixed designation C1843; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi
2、on. 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 test method is used to determine compliance withSpecification C967 for the requirements of moisture in uraniumore concentrat
3、es (UOC). A procedure is given to determine theapproximate temperature for drying the UOC; normally 110Cbut possibly 165C for uranyl peroxides. The dried uraniumore-concentrate resulting from this procedure is then used forperforming additional analyses described in SpecificationC967.1.2 The values
4、stated in SI units are to be regarded as thestandard. The values given in parentheses are mathematicalequivalents that are provided for information only and are notconsidered standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is ther
5、esponsibility 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:2C859 Terminology Relating to Nuclear MaterialsC967 Specification for Uranium Ore Concent
6、rateC1022 Test Methods for Chemical and Atomic AbsorptionAnalysis of Uranium-Ore ConcentrateC1075 Practices for Sampling Uranium-Ore ConcentrateE11 Specification for Woven Wire Test Sieve Cloth and TestSieves3. Terminology3.1 Except as otherwise defined herein, definitions of termsare as given in Te
7、rminology C859.4. Summary of Test Method4.1 The need to establish an appropriate temperature fordrying may only occur once for a specific ore concentrate butmay be evaluated if the property of the ore is suspected to havechanged. An example of a UOC material that may requiredrying at 165C is uranyl
8、peroxide. Other concentrates, such asU3O8,UO2, and UO3are generally dried at 110C.4.2 A weighed portion of uranium ore concentrate sample isplaced into an oven that is capable of maintaining a tempera-ture of 110 or 165C. The sample is heated and weighedperiodically to a constant weight or an insign
9、ificant change inweight.4.3 A weight change that is insignificant would be definedby the sample size and the required precision.5. Significance and Use5.1 The test method within this standard is used to demon-strate uranium ore-concentrate material meets the moisturespecification defined in Specific
10、ation C967 or other applicablerequirements.6. Safety Precautions6.1 Proper precautions should be taken to prevent inhalationor ingestion of uranium-ore concentrate during ore evaluation,sample preparation, sample analysis, and sample packaging.Precautions used to prevent inhalation or ingestion shou
11、ldinclude a ventilation system and personal protective equip-ment. Generally the ventilation system is in the form oflaboratory hoods with a dust collection system. Personalprotective equipment used should be a respirator designed forparticulate matter.7. Apparatus7.1 Drying Oven, capable of maintai
12、ning 110 or 165C.7.2 Desiccator.7.3 Vacuum Pump, capable of reducing pressure by 34 kPa(5 psi) (25 cm of mercury).7.4 Weighing trays.7.5 Pulverizer.7.6 Blender.7.7 Balance, 3000 g capacity, readable to at least 0.1 g.1This test method is under the jurisdiction of ASTM Committee C26 on NuclearFuel Cy
13、cle and is the direct responsibility of Subcommittee C26.05 on Methods ofTest.Current edition approved Dec. 15, 2016. Published January 2017. DOI: 10.1520/C1843-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Boo
14、k of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recogni
15、zed principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.17.8 Sample Jars, glass with metal lids, able to hold 150 g oras ag
16、reed upon.7.9 Test Sieve, 0.177 mm (U.S. Sieve 80 mesh).7.10 Test Sieve, 0.149 mm (U.S. Sieve 100 mesh).NOTE 1See Specification E11.7.11 Flat Iron, able to heat sample jar lids to 82C.8. Reagents8.1 Anhydrous Calcium Sulfate or equivalent.9. Sample Size9.1 The sample size will be determined by the s
17、amplecollected from Practice C1075. This standard practice shouldgenerate a sample of at least 1300 g or 0.01 % of the UOC bulkshipment, depending on which sampling method is used.NOTE 2A smaller sample size may be used as long as the laboratorycan demonstrate performance characteristics agreed upon
18、 by the buyer andseller.10. UOC Evaluation10.1 The primary objective is to establish the relationshipbetween the UOC sample and the dry UOC. If Practice C1075was followed for sampling, then 7 UOC samples of approxi-mately 1300 g each will be provided from the secondarysample drum for the test sample
19、 and subsequent testing.10.2 One of the seven test pans should be placed in the ovenand dried at 110 6 2C and evaluated for weight loss after 24h.10.3 The temperature to be used for drying the UOC todemonstrate compliance with the specification is determinedby returning the sample to the oven and re
20、weighing the sampledaily for a period of seven days to determine if a stable weightcan be obtained at 110 6 2 C. If a stable weight cannot beobtained, then the sample must be dried at 165 6 2C.10.4 If the test sample gains weight or shows no change inweight, the remaining 6 UOC samples are pulverize
21、d, blended,and packaged without additional drying. Complete 11.1through 11.2 and move to Section 14.11. Sample PreparationNOTE 3If testing for extractable organic is to be done, then anapproximate 150-g portion of a blended, but un-ground and undriedsample is packaged as described in Section 14.1.11
22、.1 Pulverize two of the secondary samples collected inaccordance with Practice C1075 in a pulverizer.NOTE 4Uranyl Peroxides may need to be dried first and thenpulverized and blended prior to packaging.11.2 Transfer the two samples, each containing about 1300g pulverized material to a blender, and bl
23、end for 15 min.Remove a 100-g portion of the blended sample. Pass 100 % ofthe sub-sample through a screen with apertures of 0.177 mm(U.S. Sieve 80 mesh), and retain no more than 10 % of thesample on a second screen with apertures of 0.149 mm (U.S.Sieve 100 mesh). If material is retained on the 80 me
24、sh screen,or more than 10 % of the sample on the 0.149 mm (U.S. 100mesh) screen, repeat the pulverization and blending processesuntil this requirement is achieved.11.3 Divide the remaining blended material, about 2500 g,into two roughly equal portions and spread evenly in twostainless steel drying p
25、ans.12. Procedure12.1 Transfer directly two un-pulverized samples of about1300 g each, which are designated for the moisturedetermination, and spread in two tared drying pans. Weigh thepans and samples, and then place together with the pulverizedand blended samples in adjacent positions in the same
26、oven tominimize temperature and atmosphere differences among thepans. The tare weight of the tray (W1) and the weight of thetray and sample (W2) are used in the calculation in Section 13.All weights must be carried out to 60.1 g.12.1.1 The remaining two containers collected in accor-dance with Pract
27、ice C1075 are retained as extra samples in theevent additional UOC material is needed.12.2 Dry the samples at 110 6 2C (230 6 4F) or 165 62C until two successive weights at 24-h intervals until achange of no more than 0.5 g for each tray or by more than0.1 % moisture as calculated in Section 13, whi
28、chever issmaller. The final weight obtained will be used as the weight ofthe tray and dried sample (W3) in Section 13. Weighing of thetrays of UOC should be completed after the material has cooledto room temperature within a desiccator, containing anhydrouscalcium sulfate or equivalent. The moisture
29、 content assigned tothe lot is the averaged weight percent loss of the two.NOTE 5Abias may be determined and applied to the test pans to allowfor weighing without cooling.13. Calculation13.1 Calculate the percentage of moisture, M, as follows:M 5W22 W3! 3100W22 W1!(1)where:W1= weight of weighing tra
30、y, g,W2= weight of weighing tray plus sample, g, andW3= weight of weighing tray plus dried sample, g.14. Sample Packaging and Vacuum Sealing forPulverized Samples14.1 Prior to packaging, heat the jars only (not the lids), to95 6 2C (203F).14.2 As quickly as possible, place six approximately 150 gsam
31、ples (or other agreed amount) prepared in Section 11 intotared hot glass jars of appropriate capacity.14.3 Place the metal jar lids on the jars and heat with anelectrical flat iron set to control at approximately 82C (180F)for about 1.5 min to soften the sealing gasket material on theperiphery of th
32、e lids.14.4 Put the threaded ring on the jar to hold the lid in place.Do not tighten the ring at this point.14.5 Place the jars in a vacuum apparatus and reduce thepressure to about 34 kPa (5 psi) (25 cm of mercury) in a periodnot to exceed 1.5 min.C1843 16214.6 Raise the pressure to atmospheric as
33、quickly as pos-sible to ensure a good air-tight seal, as indicated by apronounced concave depression of the jar lid.14.7 Tighten the jar rings and apply appropriate labels.15. Precision and Bias15.1 Because of the variability of matrices of uraniumore-concentrate and the difficulty of maintaining th
34、e originalmoisture content during sample shipment, the precision andbias of this test method should be established by each indi-vidual laboratory that uses the method.16. Keywords16.1 moisture; UOC; uranium ore; uranium-ore concentrateASTM International takes no position respecting the validity of a
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