"Microporous ceramics" is an industrial material that can be seen everywhere in the industry. When it comes to microporous ceramics, some people must be very unfamiliar with this concept, what is it?
The history of the development of microporous ceramics
In fact, the research of global microporous ceramics began in the 40s of the 20th century, and after successfully promoting its application in the dairy and beverage (wine, beer, cider) industries in France in the early 80s of the 20th century, it began to be applied to sewage treatment and other corresponding fields.
In 2004, the world's porous ceramics market sales exceeded 10 billion US dollars, and their market sales developed at an annual growth rate of 35% due to the successful application of microporous ceramics in precision filtration and separation.
Microporous ceramics are uniform porous structures microporous porous ceramics, which is a new type of ceramic material, but also a functional structural ceramics, as the name suggests, is a ceramic body with a large number of openings or closed micropores inside or on the surface of ceramics, the micropores of microporous ceramics are very small, and their pore size is generally micron or sub-micron, which is basically invisible to the naked eye. However, microporous ceramics are actually visible in daily life, such as the ceramic filter element used in water purifiers and the atomization element in e-cigarettes.
Porous ceramics can be classified in terms of dimensions, phase composition, and pore structure (pore size, pore morphology, and pore connectivity).
According to the size of the pore size, it is divided into: coarse pore porous ceramics (pore size > 500 μm), large pore porous ceramics (pore size 100~500 μm), medium pore porous ceramics (pore size 10~100 μm), small pore porous ceramics (pore size 1~50 μm), fine pore porous ceramics (pore size 0.1~1 μm) and micropore porous ceramics. According to the structure of the pores, porous ceramics can be divided into porous ceramics with uniform porous structure and porous ceramics with non-uniform porous structure.
Microporous ceramics are a new type of inorganic non-metallic filter material, microporous ceramics are composed of aggregate particles, binders, pores and other 3 parts, with quartz sand, corundum, alumina (Al2O3), silicon carbide (SiC), mullite (2Al2O3-3SiO2) and ceramic particles as aggregates, mixed with a certain amount of binder, porous forming agent after high temperature firing, aggregate particles, binders, porous formers and their bonding conditions, determine the pore size, porosity, air permeability and other main characteristics of ceramics. Aggregates, like adhesives, are sampled according to the purpose of product use. Aggregates are usually required to have high strength, heat resistance, corrosion resistance, close to spherical shape (easy to form filtration conditions), easy granulation within a specified particle size range, and good affinity with binders. If the aggregate substrate and particle size are the same, and other conditions are the same, the pore size, porosity, air permeability and other indicators of the product can achieve the ideal purpose.
Characteristics of microporous ceramics
The pores of porous ceramics come from two parts: one part comes from the interparticle voids left during the sintering process of powder particles, and the other part comes from the pores formed by the porous former.
The pores are evenly distributed, and microporous ceramic products with the selected pore size can be produced.
Good chemical stability, chemical corrosion resistance, except hydrofluoric acid, concentrated alkali, all media have excellent corrosion resistance, through the selection of materials and process control, can be made into microporous ceramics suitable for various corrosive environments, and do not react chemically with other substances, so the fluid is not polluted by leachables and will not cause secondary pollution;
High temperature resistance, no volatilization of harmful substances, good thermal stability, no thermal deformation, softening, oxidation, can be used at -50~500°C.
High mechanical strength and stiffness, under pneumatic, hydraulic or other stress loads, the shape and size of the hole will not change;
It has strong renewability, and can basically restore the original filtration capacity by backwashing with liquid or gas, so as to have a long service life, and at the same time has good antibacterial performance, which is not easy to be degraded by bacteria.
Good adsorption performance, microporous ceramics, a porous solid surface characteristic, make it have a large inner surface, that is, a large surface energy, so it has a strong adsorption capacity, and can adsorb and filter out a large number of tiny suspended particles.
It is non-polluting, has a good clean state, is non-toxic and odorless, does not cause foreign matter to fall off, and will not cause secondary pollution, and can replace filter materials such as cotton fabrics, silk fabrics, plastics, precious metal mesh etc., eliminating the defects of these filter materials.
Applications of microporous ceramics
Microporous ceramics have the advantages of adsorption, air permeability, corrosion resistance, environmental compatibility, biocompatibility, and unique physical and chemical properties, and are widely used in the filtration of various liquids, gas filtration, and fixation of biological enzyme carriers and biological adaptability carriers.
The market prospect for the development and application of microporous ceramics is very broad, and it has become a new ceramic material developed by many scientific research institutions and manufacturers at home and abroad.
The market prospect for the development and application of microporous ceramics is very broad, and it has become a new ceramic material developed by many scientific research institutions and manufacturers at home and abroad. At present, it has been widely used in environmental protection, energy saving, aerospace, chemical, petroleum, smelting, food, pharmaceutical, biology, medicine, breeding and other industries, greatly improving the product quality and market competitiveness of these industries. As gas-liquid filtration, purification and separation, sound absorption and shock absorption, heat exchanger materials, chemical fillers, bioceramics and catalyst carriers, adsorbents, biological implant materials, special wall materials, artificial manufacturing organs and refractory materials, sensor materials, etc., they have been introduced in many disciplines and fields, which have attracted great attention from global materials disciplines.
As a new type of ceramic with a wide range of uses and broad development prospects, microporous ceramics have become a hot topic of attention.
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