ASTM D5744-2018 Standard Test Method for Laboratory Weathering of Solid Materials Using a Humidity Cell.pdf

1、Designation: D5744 131D5744 18Standard Test Method forLaboratory Weathering of Solid Materials Using a HumidityCell1This standard is issued under the fixed designation D5744; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year

2、 of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1 NOTEEditorially updated Research Report footnote information in Section 13 in December 2013.1. Scope1.1 This kinetic test me

3、thod covers a laboratory weathering procedure that (1) enhances reaction-product transport in theaqueous leach of a solid material sample of specified mass, and (2) measures rates of weathering-product mass release. Solubleweathering products are mobilized by a fixed-volume aqueous leach that is per

4、formed and collected weekly. Leachate samples areanalyzed for pH, alkalinity/acidity, specific conductance, sulfate, and other selected analytes.1.1.1 This test method is intended for use to meet kinetic testing regulatory requirements for mining waste rock and ores sizedto pass a 6.3-mm (0.25-in.)

5、Tyler screen.1.1.2 Interlaboratory testing of this method has been confined to mine waste rock. Application of this test method tometallurgical-processing metallurgical processing waste (for example, mill tailings) is outside the scope of the test method.1.2 This test method is a modification of a l

6、aboratory weathering procedure developed originally for mining wastes (1-3).2However, it may have useful application wherever gaseous oxidation coupled with aqueous leaching are important mechanismsfor contaminant mobility.1.3 This test method calls for the weekly leaching of a well-characterized so

7、lid material sample (weighing at least1000-g),1000 g) with water of specified purity, and the collection and chemical characterization of the resulting leachate. Testduration is determined by the users objectives of the test. See Guide D8187.31.4 As described, this test method may not be suitable fo

8、r some materials containing plastics, polymers, or refined metals. Thesematerials may be resistant to traditional particle size reduction methods.1.5 Additionally, this test method has not been tested for applicability to organic substances and volatile matter.1.6 This test method is not intended to

9、 provide leachates that are identical to the actual leachate produced from a solid materialin the field or to produce leachates to be used as the sole basis of engineering design.1.7 This test method is not intended to simulate site-specific leaching conditions. It has not been demonstrated to simul

10、ate actualdisposal site leaching conditions. Furthermore, the test is not designed to produce effluents that are in chemical equilibrium withthe solid phase sample.1.8 This test method is intended to describe the procedure for performing the laboratory weathering of solid materials. It doesnot descr

11、ibe all types of sampling and analytical requirements that may be associated with its application.1.9 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.9.1 ExceptionThe values given in parentheses are for information only.1.10

12、 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prio

13、r to use.1.11 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barr

14、iers to Trade (TBT) Committee.1 This test method is under the jurisdiction ofASTM Committee D34 on Waste Management and is the direct responsibility of Subcommittee D34.01.04 on Waste LeachingTechniques.Current edition approved Sept. 1, 2013Sept. 1, 2018. Published September 2013October 2018. Origin

15、ally approved in 1996. Last previous edition approved in 20122013as D5744D5744 13.-12. DOI: 10.1520/D5744-13E01.10.1520/D5744-18.2 The boldface numbers in parentheses refer to the list of references at the end of this standard.3 Additional published guidance sources are listed under 11.4 (Test Durat

16、ion), subparagraphs 11.4.4.1 and 11.4.4.2.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, AS

17、TM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12. Ref

18、erenced Documents2.1 ASTM Standards:4D75D75/D75M Practice for Sampling AggregatesD276 Test Methods for Identification of Fibers in TextilesD420 Guide for Site Characterization for Engineering Design and Construction PurposesD653 Terminology Relating to Soil, Rock, and Contained FluidsD737 Test Metho

19、d for Air Permeability of Textile FabricsD1067 Test Methods for Acidity or Alkalinity of WaterD1125 Test Methods for Electrical Conductivity and Resistivity of WaterD1193 Specification for Reagent WaterD1293 Test Methods for pH of WaterD1498 Test Method for Oxidation-Reduction Potential of WaterD223

20、4/D2234M Practice for Collection of a Gross Sample of CoalD3370 Practices for Sampling Water from Closed ConduitsD8187 Guide for Interpretation of Standard Humidity Cell Test ResultsE276 Test Method for Particle Size or Screen Analysis at No. 4 (4.75-mm) Sieve and Finer for Metal-Bearing Ores and Re

21、latedMaterialsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE877 Practice for Sampling and Sample Preparation of Iron Ores and Related Materials for Determination of ChemicalComposition and Physical PropertiesE1915 Test Methods forAnalysis of Metal

22、Bearing Ores and Related Materials for Carbon, Sulfur, andAcid-Base CharacteristicsE2242 Test Method for Column Percolation Extraction of Mine Rock by the Meteoric Water Mobility ProcedureD5744 Test Method for Laboratory Weathering of Solid Materials Using a Humidity CellE691 Practice for Conducting

23、 an Interlaboratory Study to Determine the Precision of a Test Method3. Terminology3.1 Definitions:3.1.1 acid-producing potential, AP, nmaximum potential for a solid material sample to produce acidic effluent can bedetermined based on the total sulfur present in the sample.3.1.1.1 DiscussionIt is as

24、sumed that this sulfur is present as iron sulfides (for example, pyrite) (4). This assumption leads to overestimation of theacid-producing potential of samples containing non-ferrous sulfide minerals such as galena (PbS) or non-acid-producingnon-acid-producing, sulfur-bearing minerals such as gypsum

25、 (CaSO4). The AP is commonly converted to the amount of calcium carbonaterequired to neutralize the resulting amount of the acidic effluent produced by the oxidation of contained iron sulfideminterals;minerals; it is expressed as the equivalent tonnes of calcium carbonate per 1000 tonnes of solid ma

26、terial (3). The AP is,therefore, calculated by multiplying the percent of sulfur contained in the material by a stoichiometric factor of 31.2 (5).3.1.2 interstitial water, nresidual water remaining in the sample pore spaces at the completion of the fixed-volume weeklyleach.3.1.3 leach, nweekly addit

27、ion of water to solid material that is performed either dropwise or by flooding for a specified timeperiod.3.1.4 loading, nmass of a chemical species, which is the product of the species concentration and the mass of the weeklyleachate collected.3.1.5 mill tailings, nfinely ground ore processing was

28、te (commonly passing a 150-m 100-mesh screen) (100 mesh) screen)resulting from the mill processing of ore.3.1.6 neutralizing potential, NP, ncapacity of a solid material sample to neutralize an acidic effluent while maintaining adrainage pH of at least 6.0. NP is expressed in terms of tonnes of calc

29、ium carbonate equivalent per 1000 tonnes of solid material(3).3.1.6.1 DiscussionNP can be estimated using several techniques, including the followingfollowing: (1) determining the amount of calcium and4 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Ser

30、vice at serviceastm.org. For Annual Book of ASTMStandardsvolume information, refer to the standards Document Summary page on the ASTM website.D5744 182magnesium carbonate in the sample; (2) digesting the solid material with an excess of standardized acid and back titrating witha standardized base to

31、 measure and convert the residual acid to calcium carbonate equivalents (2, 6); and (3) determining thecarbonate carbon content in the sample (for example Test MethodMethods E1915 acid base acid-base classification).3.1.6.2 DiscussionThe AP and NP are specifically applicable to the determination of

32、AP from mining wastes comprised of iron-sulfide iron sulfideand carbonate minerals. These terms may be applicable to any solid material containing iron-sulfide iron sulfide and carbonateminerals.3.1.6.3 DiscussionCalcium plus magnesium carbonate determination generally provides a reasonably accurate

33、 NPquantification for samples in whichcarbonate minerals are present. Digestion and back-titration techniques generally overestimate the capacity of mine waste samplesto neutralize acid while maintaining drainage pH 6.0. 6.0. These techniques can yield negative values if there is excess solubleacidi

34、ty on the sample. Carbonate-carbon determinations will overestimate the capacity of mine-waste samples to neutralize acidif they contain metal carbonate minerals that are not net neutralizing (for example, iron carbonates such as siderite FeCO(FeCO3)(7).).3.1.6.4 DiscussionAP and NP comprise most ac

35、id-base classifications and these two components have historically been determined by severaldifferent analytical methods (7). However, only one acid-base classification is currently an ASTM standard, Test MethodMethodsE1915. Test MethodMethods E1915 uses either pyrolysis or chemical treatment of th

36、e mine-waste sample to speciate and quantifysulfide-sulfur and carbonate-carbon concentrations, which are expressed as acid-generating potential (AGP) and acid neutralizingacid-neutralizing potential (ANP), respectively. Through this speciation, it provides a better estimate of acid generation thanh

37、istoric AP determinations in which non-ferrous and non-acid-generating sulfur minerals are present (for example, galenaPbSO(PbSO4) and gypsum CaSO(CaSO4, respectively.), respectively).3.1.7 run-of-mine, adjusage in this test method refers to ore and waste rock produced by excavation (with attendant

38、variableparticle sizes) from open pit or underground mining operations.3.1.8 waste rock, nrock produced by excavation from open pit or underground mining operations that has an economicmineral content less than a specified economic cutoff value for metallurgical processing.4. Summary of Test Method4

39、.1 This laboratory-weathering laboratory weathering procedure is designed to enhance the mass release of acidity/alkalinity,metals, and other pertinent analytes from a sample of solid material weighing at least 1000 g. This is done by providing conditionsconducive to sample oxidation and then leachi

40、ng the sample with a fixed-volume aqueous leach. Ratio of leach volume to samplemass is 0.5 : 1 or 1 : 1 0.5:1 or 1:1, depending upon the efficiency of sample wetting and amount of effluent required for chemicalanalyses. The weekly effluent produced is characterized for dissolved weathering products

41、. This test method is performed on eachsample in a cylindrical cell. Multiple cells can be arranged in parallel. This configuration permits the simultaneous testing ofmultiple splits of the same solid material sample, or of solid material samples each characterized by different compositions.4.2 Two

42、protocol options (OptionsAand B) comprise the test procedure, and these options differ only in the way that the oxygenis supplied to samples in the individual humidity cells. Option A protocol calls for weekly cycles composed of three days of dryair (less than 10 % relative humidity) and three days

43、of water-saturated air (approximately 95 % relative humidity) pumped upthrough the sample, followed by a leach with water on Day 7. Option B protocol differs from Option A in that each cell is storedfor six days under conditions of controlled and relatively constant temperature and humidity, and oxy

44、gen is supplied to the sampleby diffusion (and possibly advection) of ambient air rather than by pumping. Although a test duration as short as 20 weeks maybe suitable for some samples, more recent research indicates that a test duration well beyond 20 weeks may be required dependingupon the objectiv

45、es of the test (8, 9).5. Significance and Use5.1 The laboratory weathering procedure will generate data that can be used to: (1) determine whether a solid material willproduce an acidic, alkaline, or neutral effluent, (2) identify solutes in the effluent that represent dissolved weathering productsf

46、ormed during a specified period of time, (3) determine the mass of solute release, and (4) determine the rate at which solutes arereleased (from the solids into the effluent) under the closely controlled conditions of the test.5.2 Data generated by the laboratory weathering procedure can be used to

47、address the following objectives: (1) determine thevariation of drainage quality as a function of compositional variations (for example, iron sulfide and calcium+magnesiumD5744 183carbonate contents) within individual mine-rock lithologies, (2) determine the amount of acid that can be neutralized by

48、 the samplewhile maintaining drainage pH 6.0 6.0 under the conditions of the test, (3) estimate mine-rock weathering rates to aid inpredicting the environmental behavior of mine rock, and (4) determine mine-rock weathering rates to aid in experimental designof site-specific kinetic tests.5.3 The lab

49、oratory-weathering laboratory weathering procedure provides conditions conducive to oxidation of solid materialconstituents and enhances the transport of weathering reaction products contained in the resulting weekly effluent. This isaccomplished by controlling the exposure of the solid material sample to such environmental parameters as reaction environmenttemperature and application rate of water and oxygen.5.4 Because efficient removal of reaction products is vital to track mineral dissolution rates during the procedure, laboratoryleach volum