High-pore-density ultrathin-wall cordierite honeycomb ceramic carrier for TWC, and preparation method thereof

Abstract

The invention discloses a preparation method of a high-pore-density ultrathin-wall cordierite honeycomb ceramic carrier for a gasoline engine three-way catalytic converter. The preparation method comprises the following steps: (1) stirring an inorganic material, an organic dispersant and purified water to form a slurry, and carrying out spray drying on an inorganic powder by using a spray drying device to form a powder with excellent flowability; (2) carrying out dry mixing on the powder and an organic binder, then adding a lubricant and a dispersion medium, and carrying out wet mixing to enable the mixture to form plastic mud pellets; and (3) carrying out extrusion molding on the mud pellets obtained in step (2) to form a green body, and carrying out dielectric drying, hot air drying, cutting and firing on the green body to finally prepare the honeycomb ceramic product, wherein the inorganic material comprises acicular raw kaolin. According to the preparation method provided by the invention, the acicular raw kaolin is introduced, so that the prepared product has ultralow CTE, high yield and low cost.

Description

technical field [0001] The invention belongs to the technical field of honeycomb ceramic carrier, relates to a cordierite honeycomb ceramic carrier and a preparation method thereof, in particular to a cordierite honeycomb ceramic catalyst with high pore density (750-900cpsi), ultra-thin wall (2-2.5mil) Vector preparation method. Background technique [0002] As we all know, gasoline engines will emit exhaust gases containing hydrocarbons, carbon monoxide and nitrogen oxides (nitrogen dioxide and nitrogen monoxide) due to the combustion of fossil fuels, which will cause air pollution. In order to realize the exhaust purification of gasoline engines, it is necessary to install a three-way catalytic converter (TWC) based on cordierite honeycomb ceramic catalyst carrier in the exhaust system, and under the dual constraints of ultra-low emission limits of pollutants and fuel consumption limits, It is required that the honeycomb ceramic catalyst carrier must have higher pore dens...

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Problems solved by technology

In addition, another technique for reducing the CTE of honeycomb ceramics in the current technology is to introduce more raw kaolin. Generally, the amount of raw kaolin is ≥ 12% by mass, such as CN1329581A. Higher, the greater the number of microcracks in the product, and the closure of microcracks during heating will reduce the CTE of the product

[0004] However, the current technology of introducing boehmite (particle size ≤ 0.5 μm) to reduce the particle size of aluminum source to obtain lower CTE and higher strength honeycomb ceramics greatly increases the production cost, because the price of aluminum source with very fine particle size, such as boehmite , which is 3-5 times that of the coarser aluminum source (particle size 1-6μm), so the improvement of the performance of this thin-walled honeycomb ceramic is at the cost of increasing the production cost; and the introduction of microcracks by increasing the amount of raw kaolin reduces the The CTE method of the product will not increase the cost of raw materials, but the introduction of too much raw material will reduce the pass rate of the product sintering process. In addition, the introduction of more raw material will cause more microcracks in the product and reduce the strength of the product. High-strength thin-walled products are unfavorable

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