高炉法制备磷酸的工艺研究和开发

发布时间：2018-02-03 08:15

  本文关键词： 磷矿石 直接还原 还原率 助熔剂 还原动力学　出处：《郑州大学》2011年硕士论文　论文类型：学位论文

【摘要】：磷酸是制备精细磷酸盐和磷复肥等磷化工产品的基本原料,在工农业和国防军工以及电子等尖端科学领域都有着广泛的应用。目前,生产磷酸的工业方法主要有三种：湿法磷酸、热法磷酸、窑法磷酸,各种磷酸制备的工业方法都存在着不同的原料适应性、能耗水平、环境影响和产品纯度。 本课题研究力图探寻一种原料适应性广、能耗水平较低、环境影响小和产品纯度高的磷酸制备新工艺-高炉法磷酸工艺,利用焦炭(或无烟煤)为燃料,磷矿和熔剂为原料,在高炉中高温熔融,磷矿中的磷元素以单质磷蒸气形式还原,同时熔融物水淬冷凝制备低磷中量营养元素(硅、钙、镁)肥料,或分离稀有贵重金属(镍、钛)等,因此本课题研究对实现磷资源,尤其是低品位磷资源的全面合理综合利用,提高磷酸工业技术水平具有一定的意义。主要研究内容及结论如下： (1)分析了影响磷矿还原的各种因素(还原时间、还原温度、硅钙比),确定了磷矿还原过程的优惠工艺条件。研究表明：在磷矿还原过程中,反应温度是影响磷矿还原率的重要因素,反应温度越高还原速度越快,还原所需的间越短；硅钙比也是影响磷矿还原的另一个重要因素,随着硅钙摩尔比增大,还原率增加。综合考虑,硅钙摩尔比选取0.8-1.0之间比较适宜。磷矿随反应时间的变化率在1200℃时很小,但当升高温度到1300℃-1500℃时,磷矿随反应时间的转化速率比较大,且具有一定的规律性。 (2)分析了炉渣中的化学组分对于炉渣熔点的影响,确定NaCl和KC1作为助熔剂。通过研究加入NaCl和KCl后对磷矿还原率的影响,发现两种熔剂均有利于促进磷矿还原率的提升,KC1比NaCl作为助熔剂的作用更为明显,其增长幅度在1%-10%之间；加入量高(10%)或加入量低(5%)时磷矿还原增长幅度并不明显,加入量在5%-7%范围内最好。 (3)探讨了磷矿还原过程反应特性及还原机理。认为：磷矿首先与二氧化硅进行脱氟反应而生成2CaF2·SiO2和Ca3 (PO4) 2,生成的Ca3(P04)2通过扩散反应通过熔融液相扩散致焦炭表面进行还原的。假定在高温下还原反应主要受扩散控制,基于此假设对还原过程进行了动力学实验,确定了还原学动力学模型,并拟合出速率常数K,为工业化生产提供了必要的基础理论数据。
[Abstract]:Phosphoric acid is the basic raw material for the preparation of fine phosphate and phosphate compound fertilizer, which is widely used in the fields of industry, agriculture, national defense, military industry, electronics and so on. There are three main industrial methods for producing phosphoric acid:. The industrial methods of preparation of wet phosphoric acid, thermal phosphoric acid, kiln phosphoric acid and various phosphoric acid have different feedstock adaptability, energy consumption level, environmental impact and product purity. This paper tries to explore a new phosphoric acid preparation process with wide adaptability of raw materials, low energy consumption, low environmental impact and high purity of product, which is made of coke (or anthracite) as fuel. Phosphate rock and flux are used as raw materials in blast furnace melting at high temperature, phosphorus element in phosphate rock is reduced in the form of simple phosphorus vapor, and melt material is quenched and condensed to produce low phosphorus medium nutrient fertilizer (silicon, calcium, magnesium). Or the separation of rare and precious metals (nickel, titanium) and so on, so this study on the realization of phosphorus resources, especially the comprehensive utilization of low-grade phosphorus resources. It is of certain significance to improve the technological level of phosphoric acid industry. The main research contents and conclusions are as follows: 1) various factors affecting the reduction of phosphate rock (reduction time, reduction temperature, ratio of silica to calcium) are analyzed, and the preferential technological conditions of the process of phosphate rock reduction are determined. The results show that: in the process of phosphate rock reduction. The reaction temperature is an important factor affecting the reduction rate of phosphate rock. The higher the reaction temperature, the faster the reduction rate, the shorter the time required for reduction. The ratio of silica to calcium is another important factor affecting the reduction of phosphate rock. With the increase of the molar ratio of silica to calcium, the reduction rate increases. The change rate of phosphate rock with reaction time is very small at 1200 鈩，

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