大部分石英砂是玻璃工业的原料。然而,为了制造高级玻璃,就需要用特殊质量的石英砂(表1)。精选低品位的石英砂就可得到这种产品。通常,低品位石英砂含有各种不同的杂质(主要是铁的化合物)而呈铁锈色。存保加利亚东北部,高岭土选矿时回收了大量的这类石英砂,这类石英砂中Fe_2O_3的含量通常在0.04—0.08%之间,其中的铁是以各种不同的铁矿 Most quartz sand is the glass industry’s raw materials. However, in order to manufacture high-grade glass, special quality quartz sand is required (Table 1). Featured low-grade quartz sand can get this product. In general, low-grade quartz sand contains a variety of impurities (mainly iron compounds) and has a rusty color. In the northeastern Bulgaria, a large amount of quartz sand was recovered during the process of kaolin beneficiation. The content of Fe_2O_3 in such quartz sand is usually between 0.04 and 0.08%, of which the iron is produced from various iron ores