Method for extraction of potassium and sodium from iron ore and synchronous preparation of ironmaking burden

Abstract

The invention relates to a method for extraction of potassium and sodium from iron ore and synchronous preparation of ironmaking burden. The method includes: adding a reducing agent into an iron-containing raw material with high potassium and sodium content to prepare carbon-containing pellets of certain granularity, and subjecting an iron-containing raw material with low potassium and sodium content to mixing granulation so as to obtain a mixture; mixing the carbon-containing pellets with the mixture according to certain mass ratio, conducting material distribution and ignition, then circulating a low oxygen gas with a small CO content to perform sintering roasting, thus obtaining the ironmaking burden with certain reducibility and low potassium and sodium content, and gathering potassium and sodium in sintered precipitator dust; subjecting the precipitator dust rich in potassium and sodium to agglomeration and direct reduction to obtain a reduction product and volatile fume; further gathering compounds of potassium and sodium in the volatile fume, and carrying out sulfuric acid agitation leaching, filtering, impurity removing and evaporative crystallization, thus obtaining a potassium salt and a sodium salt. By means of the method provided in the invention, the high quality ironmaking burden can be prepared, the potassium and sodium content of the ironmaking burden can be reduced, the blast furnace alkali load can be alleviated, and extraction of potassium, sodium and other useful resources can be realized simultaneously.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy, and discloses a method for extracting potassium and sodium from iron ore and synchronously preparing ironmaking charge. Background technique [0002] In recent years, with the rapid development of my country's iron and steel industry, the contradiction of iron ore resource shortage has become increasingly prominent, and ironmaking production has been forced to use more and more inferior resources. The rapid increase in iron ore resources and consumption with high alkali metal content has made the problem of high alkali load of blast furnaces in my country more serious, which has brought great harm to blast furnace smelting. [0003] The main hazards of alkali metals to blast furnace production are: (1) Increase the pulverization rate of sinter at medium temperature reduction; cause abnormal expansion of pellets. (2) Promote and exacerbate CO 2 The gasification reaction with c...

AI Technical Summary

Problems solved by technology

[0003]The main hazards of alkali metals to blast furnace production are: (1) Increase the pulverization rate of sinter at medium temperature reduction; cause abnormal expansion of pellets

(2) Promote and intensify the gasification reaction between CO2 and coke, resulting in the reduction of the indirect reduction zone of the blast furnace and the expansion of the direct reduction zone, which in turn increases the coke ratio; makes the pore wall of coke thinner, The particle size and strength of coke are reduced, which in turn causes the air permeability of the material column (especially the air window of the reflow zone) to deteriorate, causing damage to the tuyeres

(3) Causes abnormal expansion of clay bricks and high alumina brick refractory materials in the middle and lower sections of the blast furnace, erosion or even peeling off of the hot surface of the inner lining, which greatly shortens the service life of the inner lining, and cracks the hearth bottom steel shell in severe cases

(4) Destroy the forward movement of the blast furnace, causing the air permeability of the blast furnace material column to deteriorate, and the pressure difference gradient of the material layer to increase, causing the blast furnace to collapse and suspend the material

(5) In the blast furnace with severe alkali metal cycle enrichment, due to the decrease of reflow temperature and pulverization of the charge (sintered pellets and agglomerates), the coke is seriously damaged, the air flow distribution is abnormal or the cooling intensity is too large, resulting in blast furnace, central nodule

The pre-furnace treatment is the fundamental method to reduce the alkali load of the blast furnace, but the existing technical measures have more or less problems and hidden dangers in terms of technology and environment