ZnO前驱体对铝酸钙水泥结合刚玉质浇注料性能的影响

Effect of ZnO-precursors on properties of calcium aluminate cement bonded corundum based castables

以板状刚玉、活性氧化铝为原料,铝酸钙水泥(CAC)为结合剂,选取氢氧化锌和碱式碳酸锌两种ZnO前驱体,制备了CAC结合刚玉质试样,研究了两种前驱体对CAC结合刚玉质浇注料基质的相组成和显微结构的影响,分析了影响浇注料高温性能的原因。结果表明:粒度较小的氢氧化锌(d_(50)=1.26μm)在试样制备过程中容易发生团聚,热处理后生成颗粒状的锌铝尖晶石,阻碍了CA_(6)的生长,降低了浇注料的强度;粒度较大的碱式碳酸锌(d 50=2.91μm),分散性较好,浇注料经热处理后,碱式碳酸锌生成原位纳米级ZnO,ZnO或Zn^(2+)扩散入铝酸钙相中,促进了CA_(2)之间和CA_(6)之间的烧结,显著提高了CAC结合刚玉质浇注料的高温性能。

Calcium aluminate cement(CAC)bonded corundum based castables were prepared using tabular corundum and activated alumina as the starting materials,CAC as the binder,zinc hydroxide(Zn(OH)2)and basic zinc carbonate(BZC)as the ZnO precursors.The effects of the two ZnO precursors on the phase composition and microstructure of the CAC bonded corundum based castable matrix were analyzed,and the reasons affecting the hot performance of the castables were studied.The results show that Zn(OH)2 with a smaller particle size(d 50=1.26μm)is prone to agglomerate during sample preparation and generates ZnAl_(2)O_(4) spinel grains after firing,hindering the growth of CA_(6),thus decreasing the mechanical strength of the castables.BZC with a larger particle size(d_(50)=2.91μm),which shows a sound dispersity,in-situ generates nano-sized ZnO after firing,and ZnO or Zn^(2+)diffuses into calcium aluminates,promoting the sintering of CA_(2) and CA_(6),there by enhancing the hot properties of the CAC-bonded corundum based castables.