The main research directions of powder engineering laboratory are:
Surface nano-coating modification of (1) mineral powder filler
Based on the principle of heterogeneous nucleation and crystal deposition, the chemical reaction conditions are controlled, nano-structured crystals are deposited on the surface of micron-sized inorganic mineral powder particles or industrial waste particles, and the morphology of micron-sized inorganic mineral particles is modified to form a composite material with a "core-shell" structure, which improves the interface bonding between filler and matrix in the composite material and improves the properties of the composite material. It is mainly used to develop cheap mineral materials and high value-added industrial wastes.
For the first time, the surface of heavy calcium carbonate particles was coated and modified by nano-particles, which passivated the sharp edges and corners formed by particle crushing. The test results show that the impact strength of the product is improved by 20-30% when filled into PP; The surface nano-modification of cheap resources such as calcite, wollastonite, dolomite, calcium sulfate and fly ash has been successfully realized.
(2) Orderly compounding of micro-nano particles and spheroidization of particles.
Based on the concepts of "particle structure design extends to composite material performance design" and "composite material performance planning extends to particle structure prediction", high-speed impact particle composite system (PCS) is used to composite particles with different physical and chemical properties, so that sub-particles are coated on the surface of mother particles to form functional composite particles, which lays the foundation for manufacturing functional composite materials.
Polymer composite powder: carbon black, carbon nanotubes or other thermal (electric) powders are used as sub-particles and ultra-high molecular weight polyethylene is used as master batch to prepare high-strength and low-resistance conductive engineering plastics with interpenetrating network structure. Compared with * * * mixed filling, the resistivity of composite particle products and products manufactured by * * * mixed method has decreased by nearly two orders of magnitude, and it has been used to manufacture light antistatic blades of large mine ventilators.
Metal composite powder: nano-alumina as sub-particle, electrolytic copper as mother particle. The sub-particles are coated on the surface of the mother particles by a high-speed impact particle composite system, and then the composite particles are sintered and molded. This method combines mechanical alloying with powder spheroidization technology, and realizes the compounding and spheroidization of metal-based particles at the same time, and prepares composite powder with uniform composition, good fluidity and filling property.
Nano-particle dispersion: micro-particles are used as carriers to coat nano-particles, so as to realize the high dispersion of micro-nano powder in materials. The homogenization of nano-scale artificial medium on fighter radome is realized for the first time, and the consistency of dielectric constant of radome is improved. This technology has entered the model production stage in AVIC 637 (avic special structure research institute).
Particle shape treatment: the shape treatment of natural flake graphite can improve the bulk density of powder, and the bulk density after spheroidizing treatment can be increased by more than 2 times, which can be used to prepare high-density nuclear fuel graphite balls and lithium ion battery anode materials; After shaping and spheroidizing molybdenum disilicide powder, reduced copper powder, iron powder, aluminum powder and titanium powder, the packing density is greatly improved and the material properties are improved. For example, after spheroidizing treatment, the service temperature of silicon-molybdenum rod is increased by 50℃, and the products produced by this technology have been put on the market in Shandong.
(3) Optimization of superfine processing technology and modification system of industrial powder raw materials.
By studying the mechanochemistry of grinding process and the dispersion law of ultrafine powder in strong turbulent field, the mathematical model of grinding process is established, and the internal flow field of centrifugal classifier is numerically simulated and the process parameters are optimized. On this basis, the system engineering theory is used to optimize the equipment process parameters and system composition, and a multi-objective and multi-factor system optimization method is put forward for the first time in China, which considers the relationship among process, equipment and products as a whole, forming a large-scale ultrafine grinding process optimization method that can be obtained at low cost.
According to the requirements of plastics, rubber, coatings and other industries for the functionalization of filler powder, the continuous modification process of ultrafine powder was realized for the first time in China, which improved the surface activity of mineral filler and the compatibility between mineral filler and polymer, and achieved the purpose of reducing cost and improving the properties of composite materials. The activation degree of organic surface modification of industrial mineral filler reaches above 95%; The activation degree of wet strong turbulence shear modification is above 98%.
According to the strict requirements of electronic industry on the content of conductive impurities (iron, sodium, chloride ion, etc.). ) On the surface of mineral filler (especially silica mineral filler), through the analysis of impurity formation and high-temperature purification process, the feasible technical route of producing high-purity ultrafine silica filler powder for microelectronics industry is realized. The concentration of sodium ion and chloride ion in superfine high-purity silicon micropowder is less than 1ppm, and the product quality has reached the international advanced level.
(4) micronization of biological powder and improvement of bioavailability
Through cell wall-breaking treatment, the bioavailability of biomass powder such as traditional Chinese medicine, food and mineral medicine has made a qualitative leap, which has positive academic value and social significance for the modernization of traditional Chinese medicine, the appreciation of agricultural products and the improvement of national quality of life. This technology won the second prize of national technological invention in 2007.
Under the action of external forces such as impact and extrusion, tissue tearing and cell wall rupture are formed in biological particles. Based on this research, the ultra-micro processing mechanism of natural polymer, the effect of cell wall breaking on the dissolution of effective substances and the effect of processing technology on the toxicological characteristics of traditional Chinese medicine were studied, and the micro-processing industrialization of Tongxinluo capsule powder with an annual output of 654.38+300 million tablets was realized. Because this technology is of great significance to the modernization of traditional Chinese medicine and the deep processing of agricultural and sideline products, Academician Han Qide, vice chairman of the National People's Congress and chairman of the Association for Science and Technology, cordially met the researchers of the research group and included them in the science and technology poverty alleviation plan of the Jiu San Society.
The beneficial mineral elements in medical stone were extracted by mechanochemical excitation of wet mill to improve the bioavailability of minerals.
Treating phosphate rock by mechanochemical excitation method can improve the dissolution of phosphorus and the bioavailability of crops, and realize the short-process processing and utilization of low-grade phosphate rock.