Explanation

An acid glass extrusive rock with pearl structure. Its chemical composition is similar to that of rhyolite, but its water content (2% 6%) is higher than that of rhyolite; The composition and technological properties are similar to those of pitchstone and obsidian. It is often yellow white, light flesh red, gray, grayish green, yellow green, brown, and grayish black. Almost entirely composed of glass. Crisp with pearly luster and grease luster. It has a special arc crack (pearl structure) with the characteristics of instant expansion at high temperature, and the expansion multiple can reach 730 times; The higher the expansion performance, the better the quality. Expanded perlite has excellent properties such as small bulk density, low thermal conductivity, high refractoriness and safe use temperature, good sound absorption, low moisture absorption, frost resistance, acid resistance, good insulation, etc. It is widely used in construction, metallurgy, petroleum, chemical industry, power, furnaces, cold and hot pipes, thermal insulation equipment, fertilizer conservation and soil conditioners in agriculture, etc. Generally, perlite and its raw materials are divided into three levels: the first level is high-quality products, which can be used as ultralight fillers; The second grade is of medium quality and can be used as lightweight aggregate; Grade III lower quality can be used as concrete aggregate. The quality can be preliminarily judged based on color, gloss, fracture surface, etc. The rock is pure in texture, with strong glass luster or grease luster, shell like fracture, brittle and fragile. The edges are sharp and transparent or translucent, and this kind of perlite is of good quality. Rock with lighter color generally has better expansion performance, while those with gray, gray black and black have poor expansion performance. All glassy perlite has good expansibility, while the more aphanitic, crystallite and phenocryst content, the worse the expansibility. The perlite with obvious rhyolite structure and breccia has poor expansion performance. The expansion performance is good for those with high water content, but poor for those with low water content and high iron content. China is rich in perlite resources, which are widely distributed in Inner Mongolia, Heilongjiang, Liaoning, Hebei, Henan, Shandong, Zhejiang and other places.

Classification