烧结电除尘灰浸出液中回收钾盐及联产球形碳酸钙（英文）

Preparation of potassium salt with joint production of spherical calcium carbonate from sintering dust

采用一些物理化学表征手段对包钢烧结电除尘灰的基础性质进行研究。结果表明,该烧结电除尘灰的主要成分为KCl、NaCl、Fe2O3和Fe3O4。烧结电除尘灰的水浸实验表明,烧结电除尘灰中的氯化钾可以通过水浸蒸发的方式回收。浸出液分析结果表明,浸出液中含有大量可溶性硫酸钙。为了获得纯净的氯化钾产品,这些可溶性硫酸钙需要事先进行去除。为了提供抑制硫酸钙从烧结电除尘灰中浸出溶解的理论数据指导,开展了烧结电除尘灰的浸出实验和硫酸钙在KCl、NaCl、K2SO4及其混合盐中的溶解性能实验。结果表明,在浸出过程中,采用小的液固比能很好地抑制烧结电除尘灰中硫酸钙的溶解。研究碳酸钠沉淀剂的浓度、反应温度、搅拌强度和平衡时间对制备球形碳酸钙的影响。获得了分散良好,粒径尺寸小于10μm的球形碳酸钙。同时,设计了一个从烧结电除尘灰提取氯化钾并联产球形碳酸钙副产品的工艺路线。该工艺技术可行,经济效益较好。

Several physical and chemical detection methods were used to study the basic properties of sintering dust （ESP dust） collected from Baogang Steel Corporation. The result shows that the major constituents of the ESP dust are KCl, NaCl, Fe2O_3 and Fe3O_4. Water leaching experiment on the sintering dust shows that KCl in the ESP dust can be separated and recovered by water leaching and fractional crystallization. Component analysis of leaching solution indicates that the massive calcium sulfate in the leaching solution should be removed first in order to obtain the pure potassium salt. In order to provide theoretical guidance to inhibit the dissolution of calcium ions from the sintering dust, the water leaching experiment of ESP dust and the dissolution behavior of CaSO_4 in the potassium chloride, sodium chloride, potassium sulfate and their mixed salt solution were studied. It is found that, a lower liquid-solid ratio should be chosen in the leaching process to inhibit the dissolution of calcium sulfate dehydrate. Using sodium carbonate solution as a precipitating agent, the influences of the concentration of sodium carbonate solution, reaction temperature, stirring speed and equilibrium time on the preparation of the spherical calcium carbonate were studied. Spherical calcium carbonate with good dispersing performance and grain size distribution in nanometer range of less than 10 μm was obtained. Furthermore, a potassium recovery process with joint production of spherical calcium carbonate was designed. This process is technically viable and considerable in economic benefit.