光卤石热分解制备氯化钾技术研究

发布时间：2018-04-26 08:03

  本文选题：光卤石 + 氯化钾　； 参考：《天津科技大学》2015年硕士论文

【摘要】：氯化钾是重要的钾盐资源,应用范围十分广泛,其产品主要分为农业用氯化钾和工业用氯化钾两大类。工业方面,氯化钾可以作为制造其它钾盐的原料,同时是制造焰火、火药等的重要原料,又是电解氯化镁制取金属时的电解液成分之一；农业方面,氯化钾用于配制复合肥料或者用作钾肥直接使用。在农业上用作钾肥,是速效性钾肥,是作物生长必需的营养物质,可以做基肥和追肥使用。纵观氯化钾市场,农用氯化钾需求潜力巨大,工业级氯化钾市场需求稳定,未来将呈现产需两旺的局面。沿海地区生产氯化钾主要利用光卤石冷分解的方法。该工序是将光卤石加水分解、洗涤、经离心分离后得到氯化钾产品,其母液再经蒸发浓缩结晶等过程生产氯化镁产品。在生产过程中加水量的多少不仅影响着氯化钾的收率和纯度,同时也影响着氯化镁生产的能耗。本研究利用汉沽盐场提供的光卤石为原料,主要研究内容有以下方面：通过与目前常用的冷分解生产氯化钾工艺过程进行了对比研究,分析探讨了光卤石加水分解制备氯化钾的工艺参数,得出光卤石较佳的加水分解条件为：反应温度为75℃,分解水量为1.1倍理论水量,此时氯化钾收率为69.97%,产品纯度高达97.57%。该条件与目前的冷分解法(25℃)相比,加水量可减少13.36%,液相中氯化镁含量可增加2.33%。动力学研究可以为结晶器设计和结晶过程的优化提供重要依据,本课题采用间歇动态法研究了K+,Mg2+//Cl-—H2O体系中氯化钾的结晶动力学,运用粒度无关生长模型和矩量变换法处理实验数据,分别建立了高温下氯化钾的成核速率和生长速率方程,为氯化钾在高温下的结晶过程提供理论依据。研究了高温下制备氯化钾过程中氯化钾产品粒度的影响因素,通过对加料速率、添加晶种、过饱和度、搅拌强度等各个因素进行研究,发现这些因素都对氯化钾晶体的生长有重要影响作用：降低加料速率、降低过饱和度、添加晶种、降低搅拌强度、升高结晶温度,均对晶体粒度尺寸增大有利。
[Abstract]:Potassium chloride is an important resource of potassium salt, which is widely used in many fields. Its products can be divided into two categories: agricultural potassium chloride and industrial potassium chloride. In industry, potassium chloride can be used as a raw material for the manufacture of other potassium salts, as well as an important raw material for the manufacture of fireworks, gunpowder, etc. It is also one of the electrolytic components in the electrolysis of magnesium chloride to produce metals; in agriculture, Potassium chloride is used as a compound fertilizer or as a potassium fertilizer for direct use. As potash fertilizer in agriculture, it is an available potash fertilizer and a necessary nutrient for crop growth. It can be used as base fertilizer and topdressing fertilizer. Looking at the market of potassium chloride, the demand potential of agricultural potassium chloride is great, the demand of industrial grade potassium chloride market is stable, and the situation of production and demand will be prosperous in the future. The method of cold decomposition of carnallite is used to produce potassium chloride in coastal area. In this process, carnallite is decomposed with water, washed, separated by centrifugation to produce potassium chloride product, and its mother liquor is then evaporated, concentrated and crystallized to produce magnesium chloride product. The amount of water added in the production process not only affects the yield and purity of potassium chloride, but also affects the energy consumption of magnesium chloride production. In this study, carnallite from Hangu Salt Farm was used as raw material. The main contents of this study were as follows: compared with the commonly used process of cold decomposition to produce potassium chloride, The technological parameters for the preparation of potassium chloride from carnallite by water decomposition were analyzed and discussed. The optimum conditions for water decomposition of carnallite were as follows: the reaction temperature was 75 鈩，

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