ASTM D715-86 (2020) pdf free.Standard Test Methods for Analysis of Barium Sulfate Pigment.
1. Heary Liquid (sp gr 2.9)- -Dissolve 4 parts by weight of potassium iodide (KI) in 6 parts of warm water, and add, while stirring constantly, 5 parts of mercuric iodide (Hgl2).Evaporate over a hot plate or gas flame, protected by screen cloth, until a light crystalline scum forms. Cool, and filter through heavy paper. The solution will be a clear, deep, amber color of about 3.2 specific gravity. All filter washings showing a yellow color should be saved and evaporated. Determine the 3.1. specific gravity accurately by means of a specific gravity bottle, and correct the solution to a specific gravity of 2.9 at room temperature by adding water. Prepare approximately 200 mL of the solution.
2.1 Carefully weigh 10 g of the finely ground dry barium sulfate pigment and transfer to a carefully dried 125-mL clear glass separatory funnel of the long narrow type. Add 100 mL of the heavy liquid (sp gr 2.9), stopper, and shake well to liberate any air bubbles that might adhere to the particles, and also to break up all agglomerates. Set the separatory funnel aside and allow to stand in a perpendicular position for 2 h, or for a suficient time for the particles to rise or sink.
2.2 Draw off the heavy particles through the stopcock into a beaker along with 75 mL of the liquid. Add 50 mL of fresh heavy liquid (sp gr 2.9) to the float particles and liquid remaining in the separatory funnel and repeat the procedure as described in 17.1.
2.3 Draw off the heavy particles along with 75 mL of the liquid and add to those drawn off in accordance with 17.1, leaving the float particles in the funnel. Wash the particles remaining in the funnel with fresh heavy liquid (sp gr 2.9), filter through a No. 2/0 paper (see Specification E832), and wash free of solution with warm water.ASTM D715 pdf download.