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ASTM D715-86(R2020) pdf free download

ASTM D715-86(R2020) pdf free download.Standard Test Methods for Analysis of Barium Sulfate Pigment
1. Scope
1.1 These test methods cover the analysis of barium sulfate pigment. 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Significance and Use
3.1 These test methods are used to determine the purity of barium sulfate and to determine the concentration of known impurities. This information is useful to producers and users as an aid in the manufacture of coatings.
4. Purity of Reagents
4.1 Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 3 Other grades may be used, pro- vided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 4.2 Unless otherwise indicated, references to water shall be understood to mean reagent water conforming to Type II of Specification D1193.
6. Procedure
6.1 Weigh to 0.1 mg approximately 0.5 g of the sample into a platinum crucible, add 3 g of Na 2 CO 3 , mix thoroughly, and fuse until the melt is clear. Allow the melt to cool and then leach in a platinum dish with hot water until it is entirely disintegrated. Filter on a close-texture paper and wash thor- oughly with hot Na 2 CO 3 solution (30 g/L).6.2 Transfer the filter paper containing the insoluble carbon- ates to a 250-mL beaker and acidify with concentrated HCl (sp gr 1.19). Wash the fusion crucible with HCl (sp gr 1.19) so that no barium is lost. Boil the solution, filter into a 600-mL beaker, and wash well with water. Add methyl red indicator solution, and add NH 4 OH (sp gr 0.90) until the solution is slightly alkaline. Add 6 mL of HCl (1+1), and dilute to 300 mL. 6.3 Heat the solution to boiling, and add 5 g of (NH 4 ) 2 SO 4 dissolved in 40 mL of water. If low-grade material is being analyzed, the (NH 4 ) 2 SO 4 solution should be added drop by drop from a buret to minimize inclusion. If the barytes is a rather pure product (95 to 99 % BaSO 4 ), this is not necessary, since the only nonvolatile constituents of the solution will be barium salts. Allow the precipitate of BaSO 4 to digest for 4 h or overnight, and filter through a close-texture paper. Wash the precipitate with as little cold water as possible (consistent with the purity ofthe precipitate), ignite in an oxidizing atmosphere, and weigh as BaSO 4 .
10. Procedure
10.1 Dissolve the soluble portion of a 1-g specimen in H 2 SO 4 (1+1), filter, and wash, keeping the volume of the solution under 100 mL. Oxidize any iron present in the filtrate by adding potassium permanganate (KMnO 4 ) until a faint pink color is obtained. Dilute the solution to 100 mL and pour into a buret graduated in 0.1-mL divisions. 10.2 Pour 100 mL of the standard color solution into a 100-mL colorimetric tube. Into a second colorimetric tube pour 10 mL of concentrated H 2 SO 4 (sp gr 1.84) and 10 mL of NH 4 CNS, dilute to 60 or 70 mL and then add the test solution from the buret until the depth of color thus produced on dilution to 100 mL exactly matches that ofthe standard. Record the number of millilitres required.

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