ASTM D79-86 (2020) pdf free.Standard Specification forZinc Oxide Pigments.
Zinc oxide functions as both a chemical and a pigment.lt is used in a variety of applications including rubber，paint,reprography，glass，chemicals，etc. In paint,it contributes tomildew protection，ultraviolet absorption，hiding power，andneutralization of acids formed upon oxidation of the paint film.4.Composition and PropertiesIn the manufacture ofFrench process zinc oxide, metallic zinc is vaporized, either ina boiler or a refining column, and the resulting vapor is burnedin a controlled manner in an orifice.The fine particles of zincoxide are cooled enough to agglomerate and are collected by asystem of fabric bags. French process oxide shall conform tothe properties listed in Table 1.Dry Pigment,American Process—In the manufacture ofAmerican process zinc oxide，zinc ore is reduced in thepresence of a carbonaceous fuel.The resulting vapor is burnedin a combustion chamber, and the fine particles of zinc oxideare cooled enough to agglomerate and are collected by asystem of fabric bags.American process oxide shall conform tothe properties listed in Table 1.
The paste shall be made by thoroughlygrinding the specified pigment with linseed oil. As received itshall not be caked in the container and shall break up readily inoil to form a smooth paint of brushing consistency. In such physical properties as are specified by thepurchaser,the pigment shall satisfactorily match a referencesample mutually agreed upon by the purchaser and the seller.The most frequently specified properties are oil absorption,tinting strength,and particle shape.Appropriate test methodsare listed in Section 6. In the event that either an acicular typeor a nodular (spherical) type of zinc oxide is desired,theparticle shape shall be determined by examining or photographing microscopic mounts ( 1000x or more) of the sampleand the mutually agreed upon standard that are to be preparedas specified in Practice E20.
Two samples shall be taken at random from differentpackages from each lot,batch,day’s pack，or other unit ofproduction in a shipment. When no markings distinguishing between units of production appear，samples shall be takenfrom different packages in the ratio of two samples for each4540 kg (10 000 1b),except that for shipments of less than10 000 lb,two samples shall be taken. At the option of thepurchaser,the samples may be tested separately or afterblending in equal quantities the samples from the sameproduction unit to form a composite sample.ASTM D79 pdf download.