| 摘要 |
A hydrophilic oleophobic filter medium in granular form and composed of glass beads dispersed in a matrix of cured cement. The granules may be utilized in conjunction with naturally occurring materials, e.g., sand and/or anthracite. The granular density can be predetermined and varied. The granular shape is regular and controllable and the granular size can be graded for each density, so that the granules in a given filter level are of varient size, having a uniformity coefficient ranging from about 1.2 to 1.7. The method of making such granules includes the steps of casting a sheet of desired density and thickness, partially curing the sheet, severing the partially cured sheet to polygonal granules, curing the granules, optionally tumbling the granules, and finally screening them for final sizing.
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