Direct-reduction ironmaking method and system for iron-containing mineral powder

[0053] Example 1

[0054] The oxygen-enriched gas from the gas furnace is passed into the shift furnace, and in the shift furnace (as a gas conditioning unit), part of the CO is consumed by the reaction of CO and steam and hydrogen is generated, and H is adjusted. 2 The volume ratio to CO is 0.8:1, and the shift gas enters CO 2 Removal device, remove or reduce most of the CO 2 , Make CO and H 2 The total concentration is about 80%, and then it is heated to about 950℃ in the heating furnace to complete the preparation of reducing gas; limonite powder with an iron grade of about 50% and a particle size of less than 0.05mm enters the cyclone preheater from the metering device to be preheated to At about 700℃, it enters the flash reduction furnace after preheating. In the flash reduction furnace, the reducing gas contacts the preheated iron-bearing ore powder and the reduction reaction occurs at 800℃. After 30-40S, it enters the cyclone separator together and directly The reduced iron is discharged from the lower part of the cyclone separator, and after cooling, direct reduced iron is obtained. After testing, the metallization rate of the product is 95%; the tail gas enters the cyclone preheater from the upper part of the cyclone separator to preheat the cold ore powder; The exhaust gas is discharged from the upper part of the cyclone preheater and enters the gas heat exchanger to heat the oxygen-enriched air for gas production or the air required for combustion in the hot blast stove. The temperature of the exhaust gas is further reduced; it enters the bag filter to remove the dust in the exhaust gas; after dust removal The exhaust gas from the exhaust gas enters the scrubbing tower to further remove the dust in the exhaust gas. Part of the scrubbed exhaust gas is used as fuel gas for heating; the other part can be used as a blending gas and oxygen-enriched gas to prepare reducing gas for recycling.

[0055] Example 2

[0056] Pipeline natural gas is passed into the reformer to be catalytically reformed into CO and H 2 Mixture, control H 2 The volume ratio to CO is 1.2:1, CO+H 2 The concentration is about 90%, and the gas temperature of the reforming furnace is controlled to 900℃ to complete the preparation of the reducing gas; enter the flash reduction furnace; iron fine powder with an iron grade of about 63% and a particle size of less than 0.074mm enters the cyclone preheating from the metering device The device is preheated to 750℃ and enters the flash reduction furnace after preheating. In the flash reduction furnace, the reducing gas contacts the preheated iron-bearing ore powder and the reduction reaction occurs at 800℃. After 20-30S, it enters the cyclone separation together. The reduced iron is discharged from the lower part of the cyclone separator. After cooling, direct reduced iron is obtained. After testing, the metallization rate of the product is 97%; the tail gas enters the cyclone preheater from the upper part of the cyclone separator to preheat the cold ore powder; The exchanged tail gas is discharged from the upper part of the cyclone preheater and enters the gas heat exchanger to heat the oxygen-enriched air for gas production or the air required for combustion in the hot blast stove. The temperature of the tail gas is further reduced; it enters the bag filter to remove the dust in the tail gas; The dust-removed tail gas enters the scrubber to further remove the dust in the tail gas. Part of the scrubbed tail gas is used as fuel gas for heating; the other part can be used as a blended gas and natural gas to prepare reducing gas for recycling.

[0057] Example 3

[0058] Pipeline natural gas is passed into the reformer to be catalytically reformed into CO and H 2 Mixture, control H 2 The volume ratio to CO is 1:1, CO and H 2 The total volume reaches about 75%, and the output temperature of the reformer is controlled to 1050℃ to complete the preparation of reducing gas; enters the flash reduction furnace; hematite powder with an iron grade of 45% and a particle size of less than 0.1mm enters the cyclone from the metering device The preheater is preheated to 500℃, and then enters the flash reduction furnace after preheating. In the flash reduction furnace, the reducing gas contacts the preheated iron-containing ore powder and the reduction reaction occurs at 850℃, and then enters together after 100~120S In the cyclone separator, the reduced iron is discharged from the lower part of the cyclone separator. After cooling, direct reduced iron is obtained. The metallization rate of the product is 95%. The tail gas enters the cyclone preheater from the upper part of the cyclone to preheat the cold ore powder; the tail gas after heat exchange is discharged from the upper part of the cyclone preheater and enters the gas heat exchanger to heat the air required for combustion in the drying hot blast stove. The exhaust gas temperature is further reduced; the exhaust gas enters the bag filter to remove the dust in the exhaust gas; the exhaust gas after dust removal enters the scrubber to further remove the dust in the exhaust gas, and part of the exhaust gas after washing is used as fuel gas for heating; the other part can be used as mixed gas and natural gas for heating Prepare reducing gas and recycle it.