White pozzolan composition and blended cements containing same

A process for converting glass fiber wastes into high quality filler and pozzolan products, comprising shredding long entangled strands of low alkali and low iron content vitreous glass fibers, said fibers having by weight an alkali content of less than 2%, and an iron content of less than 0.8% and having little or no color, the fibers being shredded into short fibers of less than 5 mm;

• adjusting the moisture content of the short fibers;
• grinding the short moisture adjusted fibers in an attrition mill;
• and fine powder classifying the ground material through a high performance dual-cyclone, dry air classification system to produce a uniform high quality substantially white product having a reflectance value of at least 80 as measured by a Technibrite TB-1C colorimeter according to the ISO 2467, 2471 method, said classification being conducted with precise control over the maximum particle size and particle size distribution so that said product is characterized by a blocky, relatively equi-dimensional particle shape wherein the average aspect ratio of the particles is less than 2:1, and with substantially no residual high aspect ratio fibers, and a P.S.D. such that at least 95% by weight of the particles are of less than 45 microns E.S.D.