低温煅烧高镁镍铁渣制备新型胶凝材料

Calcining High-Magnesium Ferronickel Slag at Low Temperature to Synthesize New Kind of Cementing Materials

摘要: 高镁镍铁渣是难于处理与利用的冶金渣，本研究将其掺混高岭土和少量烧碱低温煅烧磨细后与石灰和脱硫石膏粉混合制备新型胶凝材料，初步探讨了制备参数对水泥净浆常温养护抗压强度的影响，并通过粉末X射线衍射、扫描电子显微分析和X射线能谱分析表征了水泥石的微结构。结果表明，通过优化制备参数，水泥净浆常温养护28天的抗压强度可达近40 MPa，微米级的钙矾石板柱状晶体散布在水化硅铝酸钙非晶凝胶中形成水泥石的结构，支持形成良好的硬化强度。镍铁渣中掺入的高岭土可用富含石英的廉价低品位高岭土代替，烧碱也可望用废碱替代，从而制备水泥的成本低，为高镁镍铁渣的规模处理和增值利用提供了新的高性价比方法。

Abstract: As one kind of metallurgical slag hard to process and utilize, high-magnesium ferronickel slag, mixed with kaolin and little caustic soda, was calcined at low temperature to synthesize a new kind of cementing materials by mixing the ground calcined materials with lime and desulfated gypsum powders. The effects of preparation parameters on the compressive strength of cement pastes curing at ambient temperature were discussed and the microstructures of the pastes were characterized by powder X-ray diffraction, scanning electronic microscopy and energy dispersive X-ray spectroscopy. It is resulted that the cement pastes with optimized preparation parameters obtained the 28 d compressive strength of near 40 MPa. The pastes have the microstructures, which is consisted of micrometer-sized plate and columnar like ettringite minerals scattered among hydrated aluminosilicate gels, support favorable solidification strength. The kaolin mixed with the ferronickel slag can be replaced with cheap low quality kaolin rich in quartz and the caustic soda could come from waste caustic, so the cement fabrication is cost effective as a new method to process and utilize high-magnesium ferronickel slag in large scale with high performance-to-price ratio.