基于SiO2-CaO-Al2O3-FeOx四元系的高钙铁冶金渣协同硅铝系固废陶瓷基础研究

In China, large amount of industrial waste are produced and discharged due to the low utilization rate, making developing technology of comprehensive utilization an important issue. Utilizing industrial waste as raw materials of ceramic would be a way of high value-added. Metallurgy slag contained high calcium and iron can be used in the preparation of ceramic materials with high strength and wear resistance. But it is difficult to industrialized production due to the narrower sintering temperature interval with high content incorporation into SiO2-CaO-Al2O3-FeOx ceramic system. The project aims at the existing problem and puts forward the preparation of ceramic from metallurgical slag with synergistically Si/Al-rich wastes, for example copper tailing, to broaden the range of sintering temperature. The densification mechanism of sintering process and broaden effect of sintering interval and synergistic mechanism of mechanical properties under the SiO2-CaO-Al2O3-FeOx ceramic system would be mainly focused on. The change rule of mineral phase in Ca/Fe-rich mixture during sintering process will be discussed by software simulation combing with experimental test. The relationship among the Si/Ca/Al/Fe components and formation of liquid phase will be studied by microstructure observation and micro area composition analysis. The migration process and distribution characteristics of the main components and trace elements will be investigated by using the method of material flow analysis and macro performance testing. And the relation between the microstructure and mechanical properties of ceramic based on industrial waste will be established. In conclusion, the project will provide theoretical and practical guidance for producing high-performance ceramic from metallurgical slag or other industrial wastes with high CaO and FeOx.

我国工业固废排放量大，综合利用率低，导致堆存量巨大，亟需开发大规模资源化利用技术。利用工业固废开发陶瓷材料是高附加值的资源化利用方式。高钙铁冶金渣可用于制备高强度、高耐磨陶瓷材料，但高掺量下形成SiO2-CaO-Al2O3-FeOx陶瓷体系，烧结温度范围变窄，难以工业化生产。前期研究发现高钙铁冶金渣协同硅铝系固废（以铜尾矿为例）可拓宽该陶瓷体系烧结温度范围，本项目将重点研究高钙铁体系下钢渣-铜尾矿固废陶瓷致密化烧结和烧结温度范围拓宽机理以及机械性能协同增强机制。项目运用软件模拟和实验检测相结合分析高钙铁固废陶瓷烧结过程矿物相变化规律，利用微观结构及微区成分分析研究钙铁硅铝组分对液相生成的影响，采用物质流分析方法与宏观性能检测结合研究钢渣/铜尾矿主要成分和微量元素的迁移过程及分布特征，建立微观结构与力学性能相关关系。为冶金渣或其他高钙铁固废开发陶瓷材料及工业化生产提供理论依据和技术基础。

我国工矿业固废排放量大，综合利用率不高，导致固废堆存量巨大，亟需开发大规模资源化利用技术。钢铁行业冶炼渣与铜尾矿均为江西典型工矿业固废，项目提出利用该工业固废开发陶瓷材料是高附加值资源化利用方式之一。将铜尾矿与高钙铁冶金渣协同制备高强度、高耐磨陶瓷材料，形成不同于传统三元陶瓷体系的SiO2-CaO-Al2O3-FeOx陶瓷体系。在前期研究基础上，获得了高钙铁冶金渣、铜尾矿固废在固废基陶瓷坯体组分中掺量范围，结果表明高钙铁固废基陶瓷混合料化学组成适宜范围为：SiO2 40-60wt.%、CaO 10-23wt.%、Al2O3 12-18wt.%、FeOx（MgO）5-12wt.%。其中钢渣掺量约为20-35%，与铜尾矿总掺加量可达65 wt.%。铜尾矿可起到助熔作用，其烧结致密化温度范围约为1130°C-1160°C，钢渣掺量达到30%后，烧结试样的三点弯曲强度大约为60-118MPa。固废中镁、铁元素更利于固废基陶瓷混合料坯体形成辉石相。钢渣-铜尾矿陶瓷混合料烧结过程矿物相形成早于坯体致密化过程。这有利于坯体内部生成大量的晶体，提高坯体力学性能。含有一定量铁氧化物对于钢渣-铜尾矿陶瓷混合料坯体烧结过程有利，铁氧化物在烧结过程中不仅起到形成低共熔点进入液相，促进坯体致密化的作用，还通过固溶形式参与晶体形成过程，成为矿物相组成，但需注意控制其含量。项目通过大量实验验证了钙铁组分对烧结矿物相及宏观机械性能的影响。项目研究可充实固废在陶瓷领域利用的思路与研究方法，为冶金渣或其他高钙铁固废开发陶瓷材料提供指导。