ASTM_D_4988_-_96_2001.pdf

Designation:D 4988 96(Reapproved 2001)An American National StandardStandard Test Method forDetermination of Alkalinity of Paper as Calcium Carbonate(Alkaline Reserve of Paper)1This standard is issued under the fixed designation D 4988;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 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 the alka-linity or alkaline reserve of paper,or both.1.2 Aqualitative test is described that indicates the presenceof carbonate.(The detection limit is approximately 5%cal-cium carbonate.)1.3 A qualitative test is described that determines thealkalinity expressed as percent calcium carbonate or alkalinereserve,or both,expressed as moles per kilogram of paper.NOTE1A similar procedure for measuring the alkalinity or alkalinereserve or both of paper will be found in ISO 10716.1.4 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 applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:D 585 Practice for Sampling and Accepting a Single Lot ofPaper,Paperboard,Fiberboard,or Related Products2D 644 Test Method for Moisture Content of Paper andPaperboard by Oven Drying2D 1968 Terminology Relating to Paper and Paper Products22.2ISO Standard:ISO 10716 Paper and BoardDetermination of Alkali Re-serve32.3TAPPI Standards:T 266 Determination of Sodium,Calcium,Copper,Iron,and Manganese in Pulp and Paper by Atomic AbsorptionSpectroscopy4T 610 Preparation of Indicators and Standard Solutions43.Terminology3.1 For the meaning of terms used in this test method,consult Terminology D 1968,or The Dictionary of Paper.44.Summary of Test Method4.1 Qualitative TestThe presence of carbonate is deter-mined by immersing a sample of the paper in hydrochloric acidand observing effervescence.Any carbonate or bicarbonate saltpresent will produce this effect.4.2 Quantitative Determination of CarbonateThe papersample is subjected to digestion in a known quantity ofstandardized hydrochloric acid.Back titration with standard-ized sodium hydroxide is used to determine the amount ofhydrochloric acid consumed in the digestion process.Thesubsequent calculation for alkalinity assumes that all of thealkaline material neutralized was calcium carbonate.Thecalculation of moles per kilogram is independent of thematerial providing the reserve.5.Significance and Use5.1 Growing concern regarding the deterioration of booksand various documents in libraries and archives have led to thedevelopment of standards by standard-setting bodies for im-proved permanence in paper.By using alkaline sizing technol-ogy,it is possible to manufacture paper at a pH of 6.5 or aboveand,therefore,incorporate alkaline fillers such as calciumcarbonate.Alkaline sizing in itself improves permanence byeliminating acid from the sheet normally associated with arosin/alum sizing system.The presence of an alkaline fillergives an added measure of permanence because it has thecapability of sorbing acidic gases from the environment thatmight otherwise cause deterioration of the paper.5.2 Various paper product specifications specify an alkalireserve,frequently at a minimum of 2%calcium carbonate.Analkaline reserve of 0.4 mol/kg is provided by 2%calciumcarbonate.5.3 The qualitative test can be used to determine thepresence of carbonate,although this may not necessarilyconfirm that the paper is alkaline-sized or that the filler iscalcium carbonate.Apaper sized with a rosin/alum system andcoated with a coating containing any carbonate salt would give1This test method is under the jurisdiction of ASTM Committee D06 on Paperand Paper Products and is the direct responsibility of Subcommittee D06.92 on TestMethods.Current edition approved May 10,1996.Published July 1996.Originallypublished as D 4988 89.Last previous edition D 4988 92a.2Annual Book of ASTM Standards,Vol 15.09.3Available from American National Standards Institute,11 W.42nd St.,13thFloor,New York,NY 10036.4Available from the Technical Association of the Pulp and Paper Industry,P.O.Box 105113,Atlanta,GA 30348.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.a positive qualitative reaction.Carbonate levels of less than5%may not show positive results.5.4 The quantitative test assumes that the carbonate iscalcium and reports as such.5.5 If the sample is known to contain no other carbonate oralkaline material,then this test method can be used to deter-mine the calcium carbonate content.If the composition isunknown,or if other materials are known to be present that willreact with the acid,the results