In order to improve the performance of Al2O3-SiC-C castables for iron trough,samples were prepared using brown corundum,dense corundum,activated alumina micropowder,ball pitch,and silicon as main raw materials,calcium aluminate cement as the binder.Several kinds of silica fumes(93SiO2,96SiO2,and 99SiO2)with different particle size distributions and chemical composition were added to research the effects on the properties of castables.The results show that the sample with 99SiO2 fume has high water requirement for molding,but the bulk density is the lowest,the apparent porosity is the highest,the oxidation resistance is the worst,and the permanent linear change on heating is low after firing at 1 450 ℃ for 3 h.The bulk density and the apparent porosity of the sample with 93SiO2 fume or 96SiO2 fume are equivalent,the hot modulus of rupture of the sample with 93SiO2 fume is the lowest,and the slag resistance of the sample with 96SiO2 fume is the best.The comprehensive performance of the sample with 96SiO2 fume is the best.

以碳化硅、氮化硅和氮化硅结合碳化硅废砖为主要原料,以树脂为结合剂,对比研究了原料种类对氮化物结合碳化硅砖用泥浆性能的影响.结果表明:以合成原料制作的泥浆的锥入度随时间延长衰减较小,以废砖粉为原料的泥浆的锥入度随时间延长大幅衰减,且不稳定;三组泥浆180℃烘干试样的抗折粘结强度接近,约为22 MPa.但经中高温热处理后的强度较低,埋炭条件下处理后的试样的强度优于空气气氛处理试样.1 300℃埋炭热处理后试样的强度均超过了10 MPa;以纯碳化硅为原料的试样的抗氧化性能最好,废砖粉为原料的试样次之,加入氮化硅原料试样的抗氧化性能最差.

Effects of CaO additions( 0,0. 5%,1. 0%,1. 5%,2. 0%,3. 5%,5. 0% and 7. 0%,in mass) on phase composition and properties of zirconia products were studied using CaO partially stabilized ZrO 2 and commercial ZrO 2 as starting materials. The results show that adding CaO has obvious effects on phase composition; as CaO addition increases,ZrO 2 stability degree increases,density and thermal shock resist- ance decline; when CaO addition is 1. 5%,the specimen has the highest strength. The stress forms on the interfaces between monoclinic phase and stabilized ZrO 2 because of their different thermal expansion coef- ficients,and results in the abnormal thermal shock resistance of specimens with less stabilized ZrO 2.

To prepare uniform zirconia spherical particles with excellent flowability by spray drying process,CaO partly stabilized ZrO2 was used as the main raw materials.The spherical particles with loose density of 1.945 g/cm3with excellent flowability were obtained.The results show that suspensions and spray-dried operating conditions have great influence on the properties of zirconia particles.When the atomizer frequency varies from 100 to 110 Hz and the rotate speed of pump varies from 15 to 20 r/min,the uniform particles have excellent flowability and little defects.

In order to prepare zirconia spray granulated slurry with good flow ability and stability,influences of STPP,SHPP,PAA and PEG2000 on their rheological behavior were discussed. It is found that the best dispersant for zirconia slurry is PAA. Then an orthogonal test was designed based on the results. The average viscosity and subsidence of slurry were used as indexes and the appropriate amounts of solid phase,binder PVA and dispersant PAA were optimized. In this experiment,zirconia slurry with good properties was prepared with 85% solid,8% PVA,and 0.5% PAA.