1、Designation:D 1951 86(Reapproved 1995)e1Standard Test Method forAsh in Drying Oils and Fatty Acids1This standard is issued under the fixed designation D 1951;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A
2、 number in parentheses 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.e1NOTEUnit of measurement statement and Keywords were added editori
3、ally in May 1995.1.Scope1.1 This test method covers the determination of the residueor ash resulting from ignition,under prescribed conditions,ofall natural and synthetic drying oils and their fatty acids.Thistest method is not applicable to boiled oils.NOTE1Boiled oils do not give reproducible resu
4、lts.Lead driers arepartially reduced by the carbon to give metallic lead and oxides of variablecomposition,and zinc oxide is relatively volatile at the muffle furnacetemperature.Ash determinations on boiled oils consequently are empiricaland not highly reproducible.1.2 The values stated in SI units
5、are to be regarded as thestandard.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 whoever uses this standard to consult andestablish appropriate safety and health
6、 practices and deter-mine the applicability of regulatory limitations prior to use.Specific hazard statements are given in Section 4.2.Significance and Use2.1 Most natural and processed oils contain small amountsof ash,but the amount is insignificant.Certain,synthetic dryingoils may contain residual
7、 catalyst or other materials,thusgiving larger amounts of ash.Although the ash and metalcontent of boiled oils may be specified,the trend with new andimproved driers is toward the specification of drying time,allowing the manufacturer to obtain this in any way desired.2.2 In this test method,ash is
8、determined by igniting thespecimen under specified conditions and weighing the residue.Due to the volatility or the reduction of certain metal oxides,some inaccuracies may result.Wet ashing or extraction meth-ods may give more accurate results.3.Apparatus3.1 Crucible,porcelain or high-silica glass(N
9、ote 2),50-mLcapacity.NOTE2Platinum is not recommended.Boiled oils or oils contami-nated with driers containing lead may ruin platinum by alloy formation.3.2 Electric Muffle Furnace.3.3 Desiccator,containing an efficient desiccant.Anhydrouscalcium sulfate(CaSO4),phosphorus pentoxide(P2O5)(Warningsee
10、4.1)or concentrated sulfuric acid(Warningsee 4.2)(H2SO4,sp gr 1.84)are satisfactory.NOTE3Magnesium Perchlorate and Barium Perchlorate are alsoefficient desiccators and were previously listed in this section.Howeverbecause of their explosive danger,and the availability of other safermaterials,the rec
11、ommendation for their use has been discontinued.3.4 Oil Sample Bottle,120-mL(4-oz).3.5 Triangle,Nichrome or clay.4.Hazards4.1 Phosphorus Pentoxide is a strong oxidizer and reactsviolently with water,reducing agents and organic matter.Causes burns.Avoid contact with skin or eyes,or clothing,orinhalat
12、ion as dust.Refer to suppliers Material Safety DataSheet.4.2 Sulfuric Acid is corrosive to skin,eyes and mucousmembranes in form of liquid,mist or fumes.It causes severeburns.Take care to prevent the contact of the acid with eyes,skin or on clothing.In making dilute solutions,always add theacid to w
13、ater with care.See suppliers Material Safety DataSheet.5.Procedure5.1 Ignite the crucible in the muffle furnace at 550 to 650C.Cool slightly,place in a desiccator for 1 h,and weigh to 0.1mg.1This test method is under the jurisdiction of ASTM Committee D-1 on Paintand Related Coatings,Materials,and A
14、pplications and is the direct responsibility ofSubcommittee D01.32 on Drying Oils.Current edition approved March 27,1986.Published May 1986.Originallypublished as D 1951 61.Last previous edition D 1951 61(1984).1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 1942
15、8-2959,United States.NOTICE:This standard has either been superceded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest information.5.2 Fill a 120-mL(4-oz)sample bottle with the sample andweigh to 0.05 g.Pour about 20 g of the sample from the bottlei
16、nto the crucible supported on a triangle,using care so that nooil runs down the outside of the crucible or bottle.5.3 Heat gently by moving a flame on the bottom and sidesof the crucible until the oil ignites.Reduce the size of the flameuntil the heat is just sufficient to keep the sample burning.When the first batch of oil has burned out,add about 20 g moreof the sample and continue in the same manner until all of theoil in the 20-mL bottle has been added.Reweigh the samplebottle to obtain the