熔分赤泥生产无机纤维的基础研究

Producing inorganic fiber using red mud as the main raw material not only realizes high value-added and large-scale utilization of red mud, but also avoids social and environmental problem such as occupation of land and ecological deterioration. This project intends to excavate several key theoretical issues which restrict the preparation of inorganic fiber using red mud, main research contents are as follows..1) Optimization mechanism for the composition, fluidity and mineralogical constitution of red mud fluxes would be determined. .2) Phase separation thermodynamics, mineralogical change and control mechanism of melting process of red mud would be studied..3) Optimization mechanism for the performance of red mud fiber would be investigated..A breakthrough in producing high-quality inorganic fiber by remelting red mud would achieved and basic theoretical problems in fiber-forming process of red mud melt would be solved in this project, building theoretical and experimental foundations for melting-separation red mud modifying process and melt fibrosis process. New theory system of Al-Si-R-based inorganic fiber would be built and the raw material melting system would be optimized, realizing the goal that production energy consumption is reduced , the performance of red mud fiber is optimized and the maximum utilization of red mud is no less than 40%.

以赤泥为主料生产无机纤维，既能够实现赤泥的高值规模化利用，又避免了土地占用、生态环境恶化等社会、环境问题。本项目将研究制约赤泥制备无机纤维的多项关键理论问题，主要内容包括：1）赤泥熔渣组成、流动性、矿相结构优化机理； 2）赤泥熔化过程分相热力学及矿相变化与控制机理；3）赤泥纤维性能优化机制。本项目旨在赤泥重熔生产高品质无机纤维研究方面取得突破，攻克赤泥渣熔体成纤过程中的基础理论问题，为熔分赤泥调质及熔体纤维化奠定理论和实验基础；建立Al-Si-R系无机纤维新理论体系，优化原料熔制制度，实现生产能耗降低、赤泥纤维性能优化及无机纤维中赤泥最大利用量不低于40%的目标。

赤泥作为氧化铝行业的典型大宗固废，目前年综合利用率不足7%，其大量堆存势必造成资源的浪费和环境污染。传统的赤泥利用途径虽范围广、技术多，但由于无法实现技术性、经济性、工业性的有效结合，仍存在利用量小、成本高、附加值低、大规模推广应用难等问题。高效回收赤泥中有价金属铁后的熔分赤泥经改性采用离心法制备高品质无机纤维，是一种实现赤泥高附加值、大规模资源化的新思路、新方法，具有广泛的应用前景。在当前“双碳”目标及“两山”理念的大背景下，对工业大宗固废综合利用与资源循环型经济发展具有重要意义。本项目采用微观结构分析、宏观性能分析、分子动力学模拟、热力学及流场、温度场模拟，结合半工业化实验等手段和方法，对熔分赤泥物化特性、改性机制，改性熔分赤泥熔体离心成纤机理、传热特性、纤维化过程多因素协同调控机制进行了相关研究，形成了熔分赤泥改性重熔离心成纤关键技术，为熔分赤泥低能耗制备高品质无机纤维的产业化提供理论及技术支撑。研究结果表明：熔分赤泥制备无机纤维是可行的，但需对其进行“提硅降铝适量加钙”改性。基于SiO2-Al2O3-CaO-Na2O-TiO2五元渣系，选用SiO2/Al2O3和CaO/Na2O质量比为设计参数，对熔分赤泥进行改性，改性熔分赤泥熔体结构是以[SiO4]、[AlO4]四面体为主要组成的网络结构，改性原料体系SiO2/Al2O3不高于1.5，CaO/Na2O不高于3.0；改性熔体出炉温度应高于适宜成纤最低温度67.26~89.24℃。选用石英砂、白云石为改性剂对熔分赤泥改性并制备无机纤维，随着熔分赤泥配加量的增加，无机纤维直径呈现先增大再减小后增大趋势，渣球含量呈先减小后增加再减小趋势，而含水率变化不明显；提高熔体出炉温度和离心辊转速均可有效改善无机纤维直径和渣球含量，但对无机纤维含水率影响不大。