Manufacturing method of magnesian pellets

Abstract

A manufacturing method of magnesian pellets is particularly used in enterprises adopting a grate-rotary kiln process to manufacture the magnesian pellets. The manufacturing method of the magnesian pellets comprises ingredients by weight: 94-98% of iron powdered ore, 2-4% of high magnesium oxide (MgO) content fusing agent and 1.0-2.5% of bentonite, wherein proportion of the iron powdered ore with grain size smaller than 0.074mm is higher than 80%, and moisture content of the iron powdered ore is lower than 7.5%. The manufacturing method comprises the following steps of: evenly mixing the iron powdered ore and the high MgO content fusing agent, conducting high pressure roller-milling pretreatment, enabling the proportion of the iron powdered ore with grain size smaller than 0.005mm to be 11%-20%, and then mixing, pelletizing and roasting with the bentonite. The manufacturing method can reduce preheating temperature of the pellets, simultaneously, can further improve strength of the pellets to enter a rotary kiln, shortens high-temperature roasting time and solves the technical problems of high preheating temperature, low pellet preheating strength and long high-temperature roasting time when the MgO pellets are manufactured.

Description

technical field [0001] The invention belongs to the field of smelting, and in particular relates to a manufacturing method of magnesia pellets, which is also suitable for producing MgO pellets by mixing iron ore powder with other magnesium-containing fluxes. Background technique [0002] Years of production practice and research have shown that magnesia pellets can improve their high-temperature metallurgical properties, and the blast furnace smelting has been improved in the following aspects: (1) Coke ratio is reduced; (2) Productivity is increased; (3) Blast furnace is extended Lining life. Since the metallurgical properties of pellets were improved after adding MgO flux, MgO pellets were produced for blast furnace smelting in foreign countries in the 1970s. In 1975, Kakogawa No. 1 pellet plant of Kobe Steel Corporation began to add dolomite to produce pellets with MgO content of 1.5%-1.8%. In 1984, Cliffs Mining Company of the United States also began to add limestone-...

AI Technical Summary

Problems solved by technology

Domestic Anshan Iron and Steel Co. used to add magnesite, and Shougang Mining Company used to add limestone-dolomite to produce MgO pellets. Due to various reasons, long-term industrial production has not been realized.

Moreover, relevant production practice shows that the control of thermal parameters of MgO pellets is more difficult than that of ordinary acid pellets. difficulty

If the grate-rotary kiln process is used to produce MgO pellets, the temperature of the hot air in the grate preheating stage Ⅱ needs to be above 1000°C to ensure that the strength of the preheated pellets reaches a minimum of 400N / ball and enters the kiln requirements, and after the preheating stage II temperature exceeds 1000°C, if the current domestic material chain grate works at high temperature for a long time, it is prone to equipment accidents

Therefore, precisely because of the above reasons, the production of MgO pellets has not been successfully realized in China.