ASTM D686-93 pdf free.Standard Test Methods of Qualitative Examination of Mineral Filler and Mineral Coating of Paper.
The common use of alum in papermaking leads to thepresence of aluminum compounds in appreciable quantities,even when fillers are absent. Small quantities or traces ofcalcium, magnesium sulfates, etc., are observed in many paperscontaining no filler and are derived from the mineral constitu-ents of the pulp or left in the paper before drying, particularlyfrom a mill in which the water is hard.
Carbonates together with considerable acidsolublecalcium indicate the presence of calcium carbonate that mayexist as chalk or whiting.If HCl-soluble magnesium is alsopresent,a mixture of calcium and magnesium carbonates isindicated.A combination of barium and carbonate may exist aswitherite. Barium in this form will be shown in the HCl-treatedportion of the ash, since barium sulfate is insoluble in diluteHC1.
A positive test for acid-soluble sulfates and calciumindicates the use of calcium sulfate as crown filler，gypsum,satin white, etc. If considerable HClsoluble aluminum is alsopresent in the coating, the mineral used may be satinwhite oraluminum hydrate. If carbonates are used in conjunction withsulfides, there may be a positive test for sulfates when none arepresent.
A positive test for calcium and sulfite indicates thepresence of calcium sulfite.
The presence of considerable magnesium and silicateindicates the use of talc,agalite, or asbestine. Silica may alsoindicate the presence of clay or diatomaceous earth. Thecharacteristic diatom forms may be readily recognized onmicroscopic examination.
The residue from the portion of the ash treated withconcentrated H,Soq (9.4.1) may be clay, talc, sodium silicoalu-minate,calcium silicate,diatomaceous earth,aluminum hy-drate,or a mixture of these substances. A positive test foraluminum indicates that clay, sodium silicoaluminate,or aluminum hydrate was used.
Barium sulfate (barytes or blanc fixe) is indicated bythe formation of a precipitate on the dilution of the solution and by a positive flame test for barium on the residue.Titanium may be present as titanium dioxide alone ormixed with barium or calcium sulfates.Titanium-barium mix-tures are not likely to be found in papers made in NorthAmerica after about 1960,but may be found in papers madeearlier. Titaniumcalcium mixtures may be found in papersmade in North America and abroad. ASTM D686 pdf download.