Microporous high chrome brick and preparation method thereof

Abstract

The invention relates to a microporous high chrome brick and a preparation method thereof. According to the technical scheme thereof, the microporous high chrome brick comprises the following compositions: 40-70 wt percent of fused chromium oxide particle, 10-20 wt percent of fused chromium oxide fine powder, 0.3-5 wt percent of SiC particle, 0.3-5 wt percent of SiC fine powder, 3-15 wt percent of monoclinic zirconia micropowder, 2-15 wt percent of alumina micropowder and 4-12 wt percent of chromium oxide green fine powder, and dextrin and aluminum dihydrogen phosphate which respectively occupy 0.5-3 wt percent and 2-7 wt percent of the mixture are added as binders. The preparation method comprises the following steps of dry mixing the fused chromium oxide particle with the SiC particle for 3-5min according to the compositions, adding the aluminum dihydrogen phosphate to be wet mixed for 5-7min, then adding a mixed powder prefabricated from the fused chromium oxide fine powder, the SiC fine powder, the monoclinic zirconia micropowder, the alumina micropowder, the chromium oxide green fine powder and the dextrin, mixing milling for 15-30min, ageing the mixture, pressing to form a green body, drying, and sintering in air at the temperature 1350-1650 DEG C. The invention has the advantages of simple process, high micropore formation rate of the prepared microporous high chrome brick and good cinder permeation resistance, and prolongs the service life of a high chrome brick.

Description

technical field [0001] The invention belongs to the technical field of high-chromium bricks, and mainly relates to a microporous high-chromium brick and a preparation method thereof. technical background [0002] High chromium brick has high strength under high temperature conditions, excellent acid cinder erosion resistance and permeability, and is the key lining material for coal-water slurry pressurized gasifier. In the past ten years, with the development of the chemical fertilizer industry and the emergence of various new technologies and processes, the operating conditions of the coal-water slurry gasifier have become more and more severe. Strong corrosive gas, low melting point, low viscosity and strong acidity of slag; at the same time, with the increase of single coal input and slag discharge, the scour of high-speed airflow, and the sharp fluctuation of pressure and temperature in the furnace, the high Chrome bricks pose extremely demanding requirements. [0003]...

AI Technical Summary

Problems solved by technology

This kind of high chromium brick not only has a high firing temperature in the production process, but also has a low microporosity rate and poor cinder penetration resistance.

The reason is that when high-chromium bricks are fired in an oxidizing atmosphere, chromium oxide will be oxidized into high-valent gaseous oxides, and evaporation-condensation mass transfer fills the necks between particles, preventing volume shrinkage, making it difficult to sinter and densify, and slightly Low porosity [Liang Yonghe, Li Nan, etc. Synthesis of high chromium sintered materials at low temperature [J] Refractory Materials, 2001, 35(4): 199~201]

High chromium bricks can be completely sintered and densified at a relatively low temperature when fired in a strong reducing atmosphere such as a buried carbon atmosphere, but the grains in the brick grow abnormally and the thermal shock resistance of the material is greatly reduced (Xu Yanqing , Sun Jialin, etc. Study on the sintering properties of chromium oxide materials under atmospheric conditions [J] Journal of Wuhan University of Science and Technology, 2010, 33(2): 170~174)

The reaction process in reducing atmosphere is complex and difficult to control. For example, once coke is in direct contact with high-chromium bricks in a carbon-buried atmosphere, a reaction layer will be left on the surface, which will have a serious impact on the performance of the product (Liang Yonghe, Sun Chengxu, etc. Cr 2 o 3 -ZrO 2 Research on sintering and thermal shock resistance of materials. Refractories, 2001, 35(5): 258~260)