Method for producing potassium chloride by using blast furnace dust of iron and steel enterprises

Abstract

The invention discloses a method for producing potassium chloride by using blast furnace dust of iron and steel enterprises. The method comprises the following steps: mixing the blast furnace dust with running water according to a certain ratio in a pre-leaching process; at the end of the mixing, stirring and leaching the mixed solution in a leaching process; filtering the mixed solution in a primary filtering procedure; removing impurities out of primary filtrate in a precipitating and impurity removing procedure; leaching the primary filter residue for the second time in a secondary leaching procedure; adding a precipitator to the primary filtrate in the precipitating procedure for precipitate and removing impurities; standing still for layering or filtering after completely precipitating; carry out multi-effect crystallization on clear liquid in an evaporation crystallization process to produce potassium chloride and sodium chloride products; filtering the mixed solution to secondary filtering equipment after the secondary leaching procedure reaches the filter condition; and recycling secondary filter residue for making iron, and returning the secondary filtrate to the pre-leaching process to be used again. By adopting the method, the high potassium feature in the blast furnace dust is fully utilized, waste materials are changed into valuable resources, the damage of emission of waste to the environment is reduced, and a high-quality potassium chloride product is also produced.

Description

technical field [0001] The invention relates to a method for producing potassium chloride, which is suitable for producing potassium chloride from blast furnace gas ash in iron and steel enterprises. Background technique [0002] During the blast furnace ironmaking process, the furnace dust is led out from the top of the furnace along with the blast furnace gas. After the coarse particles are removed in the gravity dust collector through the downcomer, the blast furnace gas is subjected to deep dust removal and purification treatment by the bag filter. The dust collected by the bag filter is called bag ash, and the dust collected by the gravity dust collector is called gravity ash. The two are collectively called gas ash. It is composed of boiling point non-ferrous metals (Pb, Zn) and their oxides, alkali metal oxides, etc. It is a light, fine-grained substance and is one of the main solid emissions from iron and steel enterprises. [0003] Gas ash contains iron, carbon ...

AI Technical Summary

Problems solved by technology

A high content of alkali metal element compounds will increase the resistance of sintered dust particles with a submicron particle size structure, which will lead to a decrease in the collection and dust removal efficiency of the sintering head electrostatic precipitator and a deterioration of the operational stability of the dust removal device, which eventually manifests as sintering The concentration of smoke and dust emitted by the electrostatic precipitator at the machine head exceeds the standard and the operating energy consumption of the dust removal device increases

[0008] The gas ash is directly added to the iron ore as the blast furnace charge, and the heavy metal elements such as lead, zinc, and copper contained in it will enter the ironmaking blast furnace with the iron ore and Circulation and enrichment in the furnace seriously affects the normal production of the blast furnace: nodules in the blast furnace, resulting in shutdown of the blast furnace for overhaul and equipment safety hazards; reducing the strength of the blast furnace charge, resulting in fluctuations in the blast furnace condition and unstable production; blockage of the blast furnace The pipeline of the gas dust removal system affects the flexibility of the gas shut-off valve and makes it difficult to ignite the blast furnace

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