This paper reviews the development status of non-metallic ore superfine pulverization technology and equipment, and points out the existing problems and development directions. Non-metallic minerals, together with metal ore and fuel mines, are known as the three pillars of the materials industry. The development of the non-metallic mineral industry is one of the important indicators to measure the country's scientific and technological progress and industrial development. The value of non-metallic minerals in many industrialized countries has exceeded that of metal ore. Due to the unique physicochemical properties of non-metallic mineral products, the application of non-metallic mineral products has penetrated into almost all industrial sectors and played an increasingly important role in the national economy. The use of non-metallic minerals depends on the degree of deep processing, including ultra-fine pulverization, ultra-fine grading, fine purification and surface modification. Among them, effective ultra-fine pulverization is the premise and guarantee for various deep processing. Therefore, the development of ultra-fine pulverization technology determines the rational development and comprehensive utilization of non-metallic mineral products to a certain extent. After decades of research and development, especially in the past ten years, the non-metallic mineral industry has achieved tremendous development. Its deep processing technology has been continuously improved, narrowing the gap with industrial developed countries, and basically meeting the raw materials needed in its own industry and related fields. Quality requirements. Ultra-fine pulverization and grading technology has been able to process 10 to 1 μm of various non-metallic mineral powder raw materials as required. Most of the ultra-fine pulverization and fine grading equipment can be produced. The equipment performance and supporting technology are gradually approaching or reaching the international advanced level. Some equipments have new unique features in terms of structural performance. The preparation technology of mineral raw materials has been able to provide functional non-metallic materials for the automotive, paper, rubber, plastics, machinery, ceramics, microelectronics, specialty coatings, aerospace, composite materials and other industries. Shijiazhuang Dingmin pharmaceutical Sciences Co.,Ltd , https://www.dingminpharma.com
1 Characteristics of ultra-fine pulverization of non-metallic minerals The development and utilization of non-metallic mineral products in China began in the 1950s. So far, more than 100 non-metallic minerals with economic value have been discovered, with more than 5,000 places. As an important industrial resource, non-metallic mineral production accounts for 70% of total mineral mining [1]. Most of the non-metallic minerals are directly used in agricultural, chemical, paper, plastic, rubber and coating products after crushing and grading. Due to the wide variety of non-metallic minerals, various requirements are imposed on the particle size distribution and purity of the pulverized products depending on their uses. Therefore, the development of ultra-fine pulverization technology must adapt to its specific requirements. In general, the requirements for non-metallic minerals are as follows.
(1) Fineness. The application of non-metallic mineral products requires a certain degree of fineness. For example, kaolin and heavy calcium carbonate are used as papermaking materials, and the product fineness is -2μm, 90%, whiteness is >90%; high-grade paint filler, heavy calcium carbonate powder, is 1,250 mesh; zirconium silicate is required as ceramic opacifier The average fineness is 0 5 to 1 μm; wollastonite is used as a filler, and its fineness is also required to be <10 μm.
(2) Purity. The purity requirement of non-metallic mineral products is also one of its main indicators. This means no pollution during the comminution process and the original ingredients should be maintained. If it is a white mineral, it also requires a certain degree of whiteness. For example, the whiteness requirement of calcined kaolin and talc for papermaking is ≥90%, and the whiteness requirement of heavy calcium carbonate for paper coating, filler and high-grade paint filler is >90%. .
(3) Special requirements for powder shape. Some non-metallic mineral products impose strict shape requirements on their shapes to suit different needs. For example, wollastonite for reinforcing composite materials, its ultrafine powder is required to maintain its original needle-like crystal state as much as possible, so that the wollastonite product becomes a natural short fiber reinforced material, and its aspect ratio requirement is >8-10; Due to its multi-layer structure, the mica powder is used as a dielectric material, a high-grade pearl paint, a pearl paint material and a pearlescent pigment. The mica powder is required to be in the form of a sheet. The diameter-thickness ratio of the obtained particles should be ensured as much as possible during the crushing process. The surface should not have too many scratches, otherwise it will affect its optical effect, its diameter-thickness ratio is >40-60; paper-coated grade kaolin hopes to maintain the characteristics of flake minerals while superfine pulverization, improve the powder Coating cloaking ability.
2 Development status of non-metallic mineral superfine crushing equipment Superfine crushing equipment is the key to its overall technology. In the past, there were few manufacturers of superfine pulverizing equipment in China, and the required products were mainly processed by imported equipment or directly imported. Through the introduction, digestion, absorption and organization of technical research, we began to develop and develop all kinds of ultra-fine pulverizing and fine grading equipment. So far, the number of manufacturers of ultra-fine pulverizing equipment has reached dozens, and its equipment performance has reached the international advanced level. In recent years, dozens of patents have been published every year.