| Manganese resources have a pivotal position in all countries in the world,and 90%of them are used in the steel industry.Manganese-rich slag is an intermediate product obtained by enriching manganese in the slag through blast furnace or electric furnace smelting.It is usually light green lumps,which can adjust Mn/Fe and P/Mn when smelting silico-manganese alloys.The role of manganese alloys is also an indispensable part of the field of ferroalloys.As the global manganese-rich ore resources are declining,countries around the world generally adopt the production of manganese-rich slag for enrichment treatment of low-grade manganese ore,so as to achieve the purpose of efficient use of low-grade manganese ore.It is also important when my country's reserves of manganeserich ore are very small Realistic meaning.This paper compares the existing lowmanganese and high-iron ore smelting processes and their research status at home and abroad.At the same time,it introduces the research progress in the field of manganeserich slag.It is found that most of the current smelting processes have long process flow,high smelting energy consumption,and heavy environmental pollution.And other shortcomings.The test material used in this paper is a low-manganese high-iron ore provided by a company in Cote d'Ivoire.The chemical composition and mineral composition of the lowmanganese high-iron ore are analyzed.The raw material contains 27.7% manganese and18.1% iron.Mn/Fe= 1.53,it is a typical low-manganese and high-iron ore,and manganese is mostly in the form of Mn O2 and Mn3O4.This paper studies the theoretical analysis and experimental process parameters of preparing manganese-rich slag by changing the alkalinity reduction using coke as a reducing agent during the reduction-melting process of low manganese high iron ore.By calculating the thermodynamics of the reduction process of manganese ore and using the Phase Diagram module of the Factsage software to perform theoretical calculations on the slag system,the three factors of reaction temperature,alkalinity and carbon content have been explored to determine the mass fraction of Mn,Fe and Mn in the slag.The influence law of the recovery rate,and finally the best smelting process parameters are obtained through the response surface method optimization test.The following conclusions are obtained through the above research:(1)The thermodynamic analysis and calculation of the reduction process of lowmanganese iron ore in C?te d'Ivoire shows that as the reduction temperature increases,the reducing agent coke will undergo a gasification reaction to generate carbon monoxide.The carbon monoxide further reduces the oxides of manganese from high prices.When the thermodynamic and kinetic conditions are satisfied,the manganese oxide in the high valence state can be reduced to manganese monoxide by carbon monoxide.Manganese ore undergoes a self-decomposition process under heating.When T>1450K,high-valence manganese oxide is converted into Mn O.Under reducing atmosphere conditions,the thermodynamic conditions for the transition of manganese oxide from a high valence state to a low valence state can be met,and compared with the self-decomposition reaction of manganese ore,the transition temperature is reduced.It is concluded that coke as a reducing agent can be significantly improved The thermodynamic conditions for the reduction reaction of manganese oxide.In addition,thermodynamic analysis shows that when iron oxides are fully reduced,Mn enters the slag to achieve the purpose of enriching manganese.Simultaneously,the theoretical melting point of the slag system is 1366.84?through the simulation of the Equilib module of the Factsage software.(2)The single factor test shows that the reaction temperature,alkalinity and carbon content all have different degrees of influence on the reduction-melting process of manganese ore.In the temperature range of this test,increasing the temperature is beneficial to the enrichment of manganese in the slag,and when the temperature is1400 ?,the recovery rate of Mn in the slag phase reaches the maximum.At the same time,it can be It is found that increasing the temperature is beneficial to the separation of slag and iron,so the reaction temperature should be selected as low as possible under the premise of ensuring good separation of slag and iron.In the process of reducing and smelting manganese ore,increasing the basicity is conducive to the enrichment of manganese in the slag,thereby improving the grade of manganese-rich slag.When the carbon content is in the range of 10% to 15%,the mass fraction of Mn in the slag and the recovery rate of Mn element in the slag both achieve larger values.At the same time,if the carbon content is too low,the Fe reduction will be insufficient,and if it is too high,the Mn recovery rate will decrease and the slag-iron separation will be worse.(3)Based on the Box-Behnken theory,the response surface test plan is determined.After data fitting is performed on the multiple quadratic regression equation of manganese element recovery established by the response surface method optimization test,the conclusion shows that three factors affect manganese in the slag The significance of the recovery rate is as follows: reaction temperature> carbon content> alkalinity.The best theoretical smelting data obtained through the response surface optimization test are:reduction temperature 1402.36?,alkalinity 0.10,and carbon content 10.04%.Due to the limitation of the actual test process conditions,the optimal theoretical process parameters are determined as: reduction temperature 1402?,alkalinity R=0.10,carbon content 10%,confirmatory tests are carried out under this parameter level,and the recovery rate of Mn is obtained.The average value is 93.13%,which is small in error with the simulation results,indicating that the model is reliable and a qualified manganese-rich slag with a manganese content of more than 40% can be obtained. |
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