矾土对Al2O3-SiO2质可塑料性能影响

Effects of Bauxite on Property of Al_2O_3-SiO_2 Plastic Refractory

以4种不同Al2O3含量的矾土及SiO2微粉和Al2O3微粉为原料,以Al(H2PO4)3/H3PO4和铝酸钙水泥为结合剂和促凝剂,通过混炼、成型、养护、烘干等工序制备了Al2O3-SiO2质可塑料。通过引入不同品位矾土原料,重点研究不同Al2O3含量的矾土原料对烘干后及1100℃烧后可塑料体积密度、常温强度、烧后线变化率、耐磨性、矿物相组成及基质微观结构的影响。结果表明,随着矾土Al2O3含量增大(即提高矾土品位),烘干后和烧后Al2O3-SiO2质可塑料体积密度逐渐增大,常温强度减小。随着原料矾土品位提高,可塑料烧后矿物组成中刚玉相特征峰强度会逐渐增强,矾土中杂质及铝酸钙水泥对可塑料起助烧结作用。矾土中Al2O3含量增大,会增大骨料颗粒强度,但会降低基质烧结性,最终导致基质与骨料强度匹配性变弱,烧后可塑料磨损量增大,耐磨性降低。

Al2O3-SiO2 plastic refractory was produced with raw materials including four kinds of bauxites with different content of Al2O3, SiO2 powder and Al2O3 powder, Al（H2PO4）3/H3PO4 and calcium aluminate cement as binding agent and coagulant, through the process of mixing, forming, curing, drying and so on. The effect of bauxite with different content of Al2O3 on bulk density, strength at room temperature, linear change rate, wear resistance, phase composition and microstructure in matrix of plastic refractories that were dried and burned at 1100℃ respectively was studied through the introduction of different grade of bauxite in the plastic refractories. The results show that the bulk density of Al2O3-SiO2 plastic refractory dried and burned will increase with Al2O3 content in bauxite（meaning that the grade of bauxite was developed）, which followed that the strength will decrease at room temperature. The crystalline characterization of corundum will be strengthened with bauxite grade being developed in the formula. The sintering aid of plastic refractories can be played by the impurities in bauxite and the calcium aluminate cement. The increasing Al2O3 in bauxite will increase the strength of aggregate particle, will reduce the sintering of the matrix, and will result that the strength match between the matrix and aggregate of plastic refractories will be weakened, which increases the amount of wear, and reduces the wear resistance.