高磷铁矿粉烧结脱磷机理与方法

The high-phosphorus iron ore dephosphorizing in sinter is a new topic on iron ore fine agglomeration. In this project, ordinary sintering, interrupted sintering and mini-sintering applied. To achieve dephosphorization of high-phosphorus iron ore fine in sinter, many kinds of measures, such as changing sinter process parameters, or adding high efficient dephosphorizing agents, was done basing on the thermodynamic calculation. At the same time, with mineralogical microscope, XRD, electron microscope and chemical analysis, we tracked the existence and evolution rules of the phosphorus from ore to sinter and explored the effective method of sintering dephosphorization. The main study contents include: Thermodynamic calculation and feasibility analysis of sintering dephosphorization. Through the mineralogical microscopic analyzing of layer anatomizing experiments of the sintering material column, we will study the distribution and existence of phosphorus in different sintering zones, and obtain the change rules of phosphorus. By analyzing the strength, degradation ratio and reductivity of the sinter, we will study the influence law of high-phosphorus iron ore on sintering process and sinter quality. Through improving the sintering process parameters or adding dephosphorizing agents, we will study dephosphorizing mechanism and method of sintering, dephosphorizing product recycling and its treatment. And finally make the high-phosphorus iron ores, whose phosphorus content is exceeding 0.5%, dephosphorize effectively in the sintering process. To decrease the cost of mineral separation and environmental pollution, and to provide technical and theoretical support for large-scale application of the high-phosphorus iron ore fine in sintering.

高磷铁矿的烧结脱磷是铁矿粉造块领域的新课题。本课题综合运用普通烧结、间断烧结和微型烧结等实验手段，在热力学计算的基础上，通过改变烧结工艺参数或添加高效脱磷剂等多种措施实现高磷铁矿粉的烧结脱磷。同时，借助矿相显微镜、XRD、电镜、化学分析等微观分析手段，追踪磷从矿石转变为烧结矿过程中的赋存状态及演变规律，探索烧结过程中有效脱磷的方法。主要研究内容包括：烧结脱磷的热力学计算与可行性分析；通过烧结料柱分段解剖实验研究烧结矿形成过程磷的分布及赋存状态，判定磷的转变规律；通过对烧结矿强度、粉化率、还原性等分析研究高磷铁矿石对烧结过程及烧结矿质量的影响规律；通过改善烧结工艺参数及配加脱磷剂研究烧结脱磷机理与方法、脱磷产物回收与处理等，最终使含磷高于0.5%的高磷铁矿石在烧结过程中有效脱磷，从而达到降低采选成本和环境污染的目的，为烧结生产大规模应用高磷铁矿粉提供技术及理论支撑。

我国高磷铁矿资源丰富，储量高达40亿吨，含磷量高限制了其有效开发利用，若能合理脱除磷元素，将大大降低钢铁企业的原料成本。本项目以高磷矿为原材料，研究了高磷矿的矿物组成、显微形貌、烧结基础特性等性能，建立了配碳量及高磷矿配比与烧结矿之间的关系；采用factsage软件模拟计算了磷在烧结过程中分布规律与转变过程，绘制了气化脱磷的优势区图，开发了脱磷剂，并结合热力学原理和吉布斯自由能函数分析了脱磷剂中各成分及其相互之间的耦合作用；采用差热分析仪研究了高磷矿气化脱磷的动力学，获得了气化脱磷动力学参数，确定了气化脱磷反应机理函数；采用烧结工艺，并通过单一变量法研究了脱磷剂之间及其耦合作用和烧结工艺参数对气化脱磷率的影响规律，构建了各成分与气化脱磷率之间的关系，获得了合理烧结工艺参数，并在此基础上借助微观检测手段分析了含磷矿物的转变规律，揭示了气化脱磷机理；最终，通过微波烧结、小球烧结及含碳球团工艺进一步研究了高磷矿的气化脱磷工艺，且开发脱磷产物的回收利用工艺。通过开展上述研究，结果表明：高磷矿是由赤铁矿、磷灰石、绿泥石、石英以及白云石等主要矿物组成，且磷灰石主要呈环状并与赤铁矿构成环形相间的鲕状结构；高磷矿的同化性能、流动性能较好，而且较易生成铁酸钙，因此高磷矿适合用于作为烧结原料；当配碳量为4.14%、高磷矿配比为48.10%时，烧结矿综合指标较好；采用Factsage软件对气化脱磷进行了热力学模拟，得出葡萄糖、SiO2、SiC及CaCl2等成分对气化脱磷还原开始温度的影响以及脱磷剂的作用机理；采用差热分析仪对高磷鲕状赤铁矿气化脱磷进行动力学研究，得出气化脱磷反应活化能为250.55kJ·mol-1，反应机理函数为二维扩散Valensi方程；通过微型烧结实验研究了CaCl2、SiO2、Na2CO3、C6H12O6、SiC及其它们耦合作用对高磷铁矿气化脱磷的影响规律，优化了烧结气化脱磷的工艺参数，得出配碳量为4%、碱度为1.2、温度越高、粒度越细，越利于气化脱磷率提高；采用其他方式处理高磷矿，气化脱磷率达到25.71%。