Technology of gas-based direct reduction of oxidized pellets with high grade hematite concentrates by travel grate process
Iron and steel industry is a typical intensively consuming-energy and CO2 emission industry.China's iron and steel industry has grown rapidly in recent decades,with China now the world's largest producer and consumer of iron and steel.Compared with iron sintering,pelleting process is more friendly environmentally with lower energy consumption and less co2 emissions.Development of direct reduction iron-making processes is important initiatives under the Background of Carbon Emission Peak and Carbon Neutrality.High grade hematite as the research object is taken to study the effect of basicity,blue charcoal dosage,binder type and dosage,thermal engineering system,etc.on the quality of green pellets and fired pellets with pure hematite concentrates by travel grate process.The experi-ment results show that compared to bentonite and Polyacrylamide(PAM),F-binder is superior to improve the qual-ity of pellets,with high grade hematite as raw material.The fired pellets prepared from high grade hematite's com-pressive strength beyond 2 500 N/P with natural basicity and F binder,while the fired pellets prepared with benton-ite and PAM require a basicity greater than 0.3 to meet the production standard.Whether F binder,bentonite or PAM as binder for the production of high grade hematite pellets,the firing performance and compressive strength of fired pellets can be improved by increasing the basicity.In a certain range,the firing properties of the pellets pre-pared from high grade hematite can be improved by adding blue charoal.The fired pellets prepared form high grade hematite and with PAM as binder,under the optimal conditions,it can be revealed that iron grade of the fired pellets is as high as 68.22%,and the mass percent of(SiO2+Al2O3)is blow 2%,and the compressive strength is over 2 500 N/P,and possess satisfactory metallurgical performance,which can meet the requirement of gas-based direct reduction process.
hematitegas-based direct reductionpelletstravel grate processpilot-scale experimentmetallurgi-cal properties
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