High-heat direct reduction dezincing method for zinc-containing dust carbon-bearing briquette

Abstract

The direct high temperature reduction process to eliminate zinc from zinc containing dust pellet includes the following steps: 1. analysis to determine the CaO, MgO, SiO2 and Al2O3 contents in zinc containing dust with zinc content lower than 5 wt% and calculate ternary (CaO+MgO) / (SiO2+Al2O3) alkalinity value; 2. adding one or several of slaked lime, lime limestone, dolomite powder and alkaline steel slag powder to zinc dust to control the alkalinity value in 1.3-2.6; 3. adding coal powder, coke powder, petroleum powder and / or graphite powder, mixing and rolling or pressing into pellet; and 4. heating the pellet at 1100-1350 deg.c for over 10 min to reduce zinc while reducing ferric iron into metal iron. The process has high zinc eliminating rate and no increased loss.

Description

technical field

[0001] The invention relates to the technical field of coal-based high-temperature direct reduction, in particular to a method for high-temperature direct reduction and dezincification of zinc-containing dust mixed with carbon material blocks. Background technique

[0002] Coal-based high-temperature direct reduction technology is one of the important methods to deal with zinc-containing dust or dust sludge generated in the process of steelmaking and ironmaking in iron and steel plants. This method is to mix zinc-containing dust with carbon to form agglomerates, and then directly reduce it at a high temperature above 800°C to make an iron-containing charge with a certain metallization rate and collect the metals such as zinc in the agglomerate to volatilize, and separate the former ( Iron-containing charge) is used for ironmaking or steelmaking in steel plants, and the latter (secondary dust rich in zinc metal and its oxides collected by volatilization) is us...

Examples

Embodiment 1

[0030] The original zinc-containing dust alkalinity is 1.1, and at 1250° C., the dezincification rates obtained after reduction respectively for 10 minutes, 15 minutes, 20 minutes, and 30 minutes are shown in the comparative example in the following table 1; meanwhile, according to the present invention, the alkalinity Add slaked lime to the original zinc-containing dust of 1.1 to increase the alkalinity. The amount of slaked lime added accounts for 3.13% of the agglomerate, and the alkalinity is increased to 1.3. Then, it is mixed with coal powder to make agglomerates. 3.82% of the block, followed by reduction at 1250°C for 10 minutes, 15 minutes, 20 minutes, and 30 minutes respectively for the dezincification rates obtained in the following table 1 of the invention example. It can be clearly seen from the following table 1 that after the invention example increases the alkalinity compared with the comparative example, its dezincification rate is also significantly improved co...

Embodiment 2

[0034] The alkalinity of the zinc-containing dust is 1.1, and at 1250° C., the dezincification rates obtained after reduction respectively for 10 minutes, 15 minutes, 20 minutes, and 30 minutes are shown in the comparative example in the following table 2; meanwhile, according to the present invention, the alkalinity Lime powder is added to the original zinc-containing dust of 1.1 to increase the alkalinity. The amount of lime powder added accounts for 5.03% of the agglomerate, and the alkalinity is increased to 1.8. Coal powder is then mixed in for agglomeration, and the amount of coking coal powder added accounts for 3.70% of the agglomerate. Then, the dezincification rates obtained after reduction at 1250° C. for 10 minutes, 15 minutes, 20 minutes, and 30 minutes are also shown in the invention examples in Table 2 below. It can be clearly seen from the following table 2 that after the inventive example increases the alkalinity compared with the comparative example, its dezi...

Embodiment 3

[0038] The alkalinity of the zinc-containing dust is 1.1, and at 1250° C., the dezincification rates obtained after reduction for 10 minutes, 15 minutes, 20 minutes, and 30 minutes are shown in the comparative example in the following table 3; meanwhile, according to the present invention, the alkalinity Adding limestone and dolomite mixed mud cake to the original zinc dust of 1.1 accounted for 14.2% of the agglomerate, increasing the alkalinity to 2.0. Then add petroleum coke powder to make agglomerates, and the amount of added petroleum coke powder accounts for 2.31% of the agglomerate. Then, the dezincification rates obtained after reduction at 1250° C. for 10 minutes, 15 minutes, 20 minutes, and 30 minutes are also shown in the invention examples in Table 3 below. It can be clearly seen from the following table 3 that after the alkalinity of the inventive example is increased compared with the comparative example, the dezincification rate is also significantly improved com...

technical field

[0001] The invention relates to the technical field of coal-based high-temperature direct reduction, in particular to a method for high-temperature direct reduction and dezincification of zinc-containing dust mixed with carbon material blocks. Background technique

[0002] Coal-based high-temperature direct reduction technology is one of the important methods to deal with zinc-containing dust or dust sludge generated in the process of steelmaking and ironmaking in iron and steel plants. This method is to mix zinc-containing dust with carbon to form agglomerates, and then directly reduce it at a high temperature above 800°C to make an iron-containing charge with a certain metallization rate and collect the metals such as zinc in the agglomerate to volatilize, and separate the former ( Iron-containing charge) is used for ironmaking or steelmaking in steel plants, and the latter (secondary dust rich in zinc metal and its oxides collected by volatilization) is us...

Examples

Embodiment 1

[0030] The original zinc-containing dust alkalinity is 1.1, and at 1250° C., the dezincification rates obtained after reduction respectively for 10 minutes, 15 minutes, 20 minutes, and 30 minutes are shown in the comparative example in the following table 1; meanwhile, according to the present invention, the alkalinity Add slaked lime to the original zinc-containing dust of 1.1 to increase the alkalinity. The amount of slaked lime added accounts for 3.13% of the agglomerate, and the alkalinity is increased to 1.3. Then, it is mixed with coal powder to make agglomerates. 3.82% of the block, followed by reduction at 1250°C for 10 minutes, 15 minutes, 20 minutes, and 30 minutes respectively for the dezincification rates obtained in the following table 1 of the invention example. It can be clearly seen from the following table 1 that after the invention example increases the alkalinity compared with the comparative example, its dezincification rate is also significantly improved co...

Embodiment 2

[0034] The alkalinity of the zinc-containing dust is 1.1, and at 1250° C., the dezincification rates obtained after reduction respectively for 10 minutes, 15 minutes, 20 minutes, and 30 minutes are shown in the comparative example in the following table 2; meanwhile, according to the present invention, the alkalinity Lime powder is added to the original zinc-containing dust of 1.1 to increase the alkalinity. The amount of lime powder added accounts for 5.03% of the agglomerate, and the alkalinity is increased to 1.8. Coal powder is then mixed in for agglomeration, and the amount of coking coal powder added accounts for 3.70% of the agglomerate. Then, the dezincification rates obtained after reduction at 1250° C. for 10 minutes, 15 minutes, 20 minutes, and 30 minutes are also shown in the invention examples in Table 2 below. It can be clearly seen from the following table 2 that after the inventive example increases the alkalinity compared with the comparative example, its dezi...

Embodiment 3

[0038] The alkalinity of the zinc-containing dust is 1.1, and at 1250° C., the dezincification rates obtained after reduction for 10 minutes, 15 minutes, 20 minutes, and 30 minutes are shown in the comparative example in the following table 3; meanwhile, according to the present invention, the alkalinity Adding limestone and dolomite mixed mud cake to the original zinc dust of 1.1 accounted for 14.2% of the agglomerate, increasing the alkalinity to 2.0. Then add petroleum coke powder to make agglomerates, and the amount of added petroleum coke powder accounts for 2.31% of the agglomerate. Then, the dezincification rates obtained after reduction at 1250° C. for 10 minutes, 15 minutes, 20 minutes, and 30 minutes are also shown in the invention examples in Table 3 below. It can be clearly seen from the following table 3 that after the alkalinity of the inventive example is increased compared with the comparative example, the dezincification rate is also significantly improved com...

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