Reducing agent for carrying out direct reduction roasting on limonite and hematite to produce reduced iron

Abstract

The invention belongs to the field of ferrous metallurgy and relates to a reducing agent for carrying out direct reduction roasting on limonite and hematite to produce reduced iron. The invention is characterized in that the reducing agent is prepared by fully and evenly mixing coal, lime stone and sodium hydroxide in a certain proportion; a direct reduction roasting-magnetic method is utilized, iron, especially iron ore existing in the form of limonite and hematite is utilized as a raw material, the reducing agent provided by the invention is added so as to carry out direct reduction roasting, and then ore grinding and magnetic separation are carried out, thus obtaining directly-reduced iron product with the iron grade larger than or equal to 90 percent and the iron recovery rate larger than 80 percent; the reducing agent plays a role in generating reducing atmosphere and promoting the iron in the limonite and hematite of ore to be fully reduced into metal iron and then recycling metal iron through a magnetic method under the condition of anaerobic roasting; and the proportion of the coal to lime stone to sodium hydroxide in the reducing agent is 100:(5-4):(2.5-1). The reducing agent is less in using amount, low in cost and good in magnetic separation effect after use.

Description

technical field [0001] The invention belongs to the field of iron and steel metallurgy, and relates to a reducing agent used for iron ore mainly existing in limonite and hematite, and adopting a direct reduction roasting method to produce reduced iron. Or add a reducing agent to the hematite ore for reduction roasting, directly reduce the limonite and hematite in the iron ore to metallic iron, and then produce direct reduced iron through grinding and weak magnetic separation. Background technique [0002] my country's iron ore resource reserves are seriously insufficient. Among the 57.671 billion tons of iron ore reserves that have been identified, the economic base reserves are only 16.686 billion tons, and there are many lean ores and few rich ores. The average grade of iron ore is only 33%. With the acceleration of my country's industrialization process, especially the rapid development of the steel industry, China has become the world's largest steel producer, while my c...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problems of high cost and low iron recovery rate caused by single use of coal as reducing agent in the existing direct reduction roasting-magnetic separation process for the production of direct reduced iron from refractory iron ore. The new reducing agent adopts the direct reduction roasting-magnetic separation process to produce direct reduced iron products with a reduced iron grade greater than 90%, so that limonite and hematite can be fully reduced during the roasting process, and achieve improved roasting efficiency and saving The purpose of investment cost, energy saving and consumption reduction

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