The siltstone deposit was discovered, explored and developed in the late 1970s and early 1980s. Because of its unique physical and chemical properties, siltstone deposits are widely used. Silica is generally white, loose soil-like, clay-like in appearance, slippery in hand twist, but not sandy, not viscous, siltstone and siliceous rock show a gradual relationship. Powdered quartz particles are very fine, with more than 80% of them in the range of 1_~30 pm. The chemical composition is mainly Si02. The content of raw ore is generally 95%~98%. It mainly distributes in the South and is the product of weathering residue. Powder quartz is used as filler, glass, ceramics, flux, raw materials of crystalline silicon, etc.
1) Powdered quartz is a good filler. The finer the filler size, the better the reinforcement performance. Natural fine particle size of powder quartz can play a very good reinforcing role in rubber and plastics. In coatings and paints industry, when powder quartz is very pure, less impurity content, wear-resistant and can maintain tone, it can improve the smoothness and durability of coatings and paints.
2) Powdered quartz has a good application in glass industry, especially in making special glasses such as optical glasses and special utensils glasses. However, in flat glass production, because of its fine particle size, it is difficult to melt.
3) Powdered quartz is widely used in ceramics and M is widely used. In the formula of electric ceramics production, the amount of powder quartz can reach 20%, and the sintering temperature of the ceramic billet can be reduced, the strength of the ceramic and the insulation performance can be increased.
4) Powder quartz can also be used in refractory products, crystalline silicon and other production.
Table 2-48-3 Requirements for Chemical Composition and Physical Properties of Powdered Quartz
4. Geological Characteristics (According to Tao Weiping et al.'China's Non-metallic Mineral Resources and Their Utilization and Development', 2002)
The occurrence horizons of siltstone deposits vary from place to place. Maokou Formation of Lower Permian in Western Jiangxi, Lower Carboniferous in Hunan, Devonian in Yunnan and Wumishan Formation of Jixian in Hebei. Fujian also has output, but the horizon is not clear.
Powdered quartz ore bodies occur mostly in the weathering crust of siliceous rocks in a planar or zonal form. The ore bodies can reach hundreds of meters to up to kilometers in length, tens of meters to 200 meters in width and tens of meters in thickness. Ore bodies are usually thick in the middle and thinner to the edge. In the plane, discontinuous sections are formed due to topographic cutting. Generally, it can be directly exposed to the surface or covered by Quaternary laterite and gravel with a thickness of ~3m. The siltstone of Wumishan Formation in Zunhua, Hebei Province is relatively special, and is stratified in chert-bearing dolomite. The brief geological characteristics of the deposit are shown in Table 2-48-4.
GEOLOGICAL CHARACTERISTICS OF CHINESE FINE QUARTZ DEPOSITS IN TABLE 2-48-4