不同CaO源固废对钙长石全固废陶瓷矿相和性能的影响

Effect of CaO sources derived from different solid waste on the minerals and properties of prepared anorthite ceramics

以大理石锯泥、烧结赤泥和钢渣3种典型高钙固废为不同钙源,分别与高硅高铝固废(煤矸石、炉渣)制备钙长石基全固废陶瓷,分析了不同钙源陶瓷在高温烧结过程的析晶、致密化和性能变化规律。研究结果表明:3种高钙固废原料中的氧化钙主要赋存矿相不同,大理石锯泥中为方解石和白云石,烧结赤泥中是文石和钙钛矿,钢渣中主要是方解石和硅酸二钙。以3种钙源为原料的全固废陶瓷均能在1100℃下生成钙长石相,但次要晶相的种类和数量存在差异性,其中,大理石锯泥陶瓷中为大量的辉石,烧结赤泥陶瓷中为少量辉石和赤铁矿,钢渣陶瓷中为少量赤铁矿。这3种钙源固废陶瓷的抗折性能和吸水率均能满足国家陶瓷标准的要求,赤泥和钢渣中存在的氧化铁和氧化钠组分降低了对应陶瓷的烧成温度。大理石锯泥为钙源的陶瓷具有相对较优的性能,在1180℃时其抗折强度为85.44 MPa,吸水率为0.35%。

Such typical high CaO content solid wastes as marble sawdust,red mud and steel slag taken as CaO sources,were used to prepare anorthite ceramics respectively with high silica and high alumina solid wastes(coal gangue and furnace slag).Their crystallization and densification during the high temperature sintering process and final properties were analyzed.The results showed that minerals containing CaO in the three high CaO solid wastes were respectively calcite and dolomite in the marble sawdust,aragonite and perovskite in red mud,calcite and dicalcium silicate in steel slag.Anorthite phase as main crystals was generated at the sintering temperature equal to and above 1100℃in all prepared ceramics.But the secondary crystals in the ceramics were different in type and quality.Among them,lots of pyroxenes were from marble sawdust in the ceramics,a small amount of pyroxene and hematite from red mud,little hematite from steel slag.Bending strength and water absorption rate of all the ceramics met the requirement of national standards of ceramic brick.Ceramics from steel slag and red mud possessing lower sintering temperature at about 1160℃,contributed to their impurity flux components of Fe_(2)O_(3) or/and Na_(2)O.The ceramics from marble sawdust had relatively excellent performance,when their flexural strength was 85.44 MPa at 1180℃,with the water absorption rate 0.35%.