FILTER

摘要

The filter consists of quartz sand the powdery part of whichis made stronger by using polyurethane binders. The polyurethanebinders contain a tin-organic compound as catalyst havingmolecular weight over 600 and modification agent of a mixture ofhighly dispersable silicic acid and/or bentonite with concentrateof aluminosilicates. The filter is particularly useful for theextraction of potable water from sectors of mining of ores andminerals.7 claims