What is Honeycomb Ceramic?
Honeycomb ceramics, as the name implies, are innovative products designed with the honeycomb shape in mind, incorporating ceramic engineering techniques. This new type of ceramic product features a honeycomb-like structure. Initially used for small car exhaust purification, it has now been widely applied in industries such as chemicals, electricity, metallurgy, petroleum, electronics, electrical appliances, and machinery, with its applications expanding and promising significant development prospects. The honeycomb ceramics are composed of numerous equal-sized holes in various shapes, with the larger holes reaching up to 120-140 per square centimeter, density ranging from 0.3 to 0.6 grams per cubic centimeter, and water absorption exceeding 20%. Due to their porous thin-walled characteristics, they greatly increase the geometric surface area of the carrier and improve resistance to thermal shock. The products produced have a network of holes primarily in triangular and square shapes, with triangles offering much better load-bearing capacity than squares and more holes in total, which is particularly important as a catalyst carrier. As the number of holes per unit area increases and the thickness of the carrier's walls decreases, the trend in ceramic carriers is towards improved resistance to thermal shock, with the temperature at which thermal shock damage occurs also increasing. Therefore, honeycomb ceramics must reduce the coefficient of thermal expansion and increase the number of holes per unit area. The coefficient of thermal expansion is a key performance indicator; currently, the international level is α25-800℃≤1.0×10^-6℃^-1, which has a certain gap compared to domestic standards, but this gap is narrowing. The raw materials for early honeycomb ceramic production mainly included kaolin, talc, clay, and especially diatomite, zeolite, expansive clay, and refractory materials. With the broadening application of extensive honeycomb ceramics and their continuously improving performance, their use is becoming increasingly widespread.
How is cellular ceramic made?
Cellular ceramics can be made from a variety of materials. The main materials include: cordierite, mullite, titanate aluminum, activated carbon, silicon carbide, active alumina, zirconia, silicon nitride, as well as composite matrices such as cordierite-mullite and cordierite-titanate aluminum.
Activated carbon powder or granules, when formed into honeycomb ceramic shapes, significantly enhance water purification and wastewater treatment capabilities, particularly in the dehydrating, decolorizing, and removing impurities from antibiotics, vitamins, injectables, and various medications. Due to the extrusion molding process of honeycomb ceramics, various additives must be added to the main raw materials to improve the plasticity and fluidity of the clay body, including binders, plasticizers, defloculants, lubricants, and wetting agents. Additionally, there are water-retaining agents, chelating agents, static preventatives, colloidal protectants, and surfactants. Currently, starch, carboxymethyl cellulose, and polyvinyl alcohol are commonly used as binders, tung oil and stearic acid as lubricants, and glycerin as a plasticizer.
What are the functions of honeycomb ceramics?
Honeycomb ceramics can be categorized into four main types based on their applications: heat storage materials, fillers, catalyst carriers, and filter materials. Honeycomb ceramic fillers offer advantages such as a larger specific surface area and better strength compared to other shapes, enabling more uniform vapor-liquid distribution, reduced bed resistance, and improved performance. Additionally, they can extend service life, and their use as fillers in the petrochemical and fine chemical industries is quite effective.
Cellular ceramic materials offer superior advantages in the field of catalysts. Utilizing a honeycomb ceramic matrix and coated with unique materials, including precious metals, rare earth metals, and transition metals, these catalysts boast high catalytic activity, excellent thermal stability, long service life, and high strength.
The development of traditional Chinese ceramics has been an incredibly long process. Today, our country's ceramic products are incredibly diverse, with many innovative techniques. Now, there is also involvement and development in the field of mechanical engineering. Honeycomb ceramics, a new ceramic technology developed in the past three decades, has a wide range of applications. For example, as a catalyst carrier, it can be used in automotive purification, boiler denitration, and industrial deodorization. It can also be used as refractory kiln equipment, capable of quick firing and improving product performance; porous thin-walled honeycomb ceramics can also filter diesel engine exhaust gases.
