Method for extracting zinc from blast furnace gas mud

Abstract

The invention discloses a method for extracting zinc from blast furnace gas mud. The method comprises the steps of drying the gas mud to obtain gas ash, placing screened gas ash in a shaft furnace, introducing nitrogen to the shaft furnace for protection, and heating the shaft furnace to a temperature between 1050 DEG C and 1200 DEG C from room temperature; conducting reduction reaction to obtain gas containing zinc; introducing the gas to a sedimentation chamber for dust removal; obtaining polymorphic zinc mixed gas, and introducing the mixed gas to a coiled cooling pipe to be cooled so that a crude zinc product can be obtained. Through self-reduction reaction of fixed carbon contained in the gas mud at the temperature of 1050-1200 DEG C, the number of procedures is reduced, the gas mud processing cycle is shortened, and production cost is reduced; meanwhile, the requirement for the amount of reduction carbon and heating carbon required by reducing zinc in the gas mud can be met, complete reduction of zinc in the gas mud is guaranteed, and then harm to iron making equipment and iron production caused by zinc existing during gas mud recycling is greatly relieved.

Description

technical field [0001] The invention relates to a recovery and treatment process for ironmaking tailings produced in the ironmaking process, in particular to a method for dezincification from blast furnace gas mud. Background technique [0002] Gas mud is the ironmaking tailings formed by the collection of fine dust or ashes (gas ash) produced in the process of blast furnace ironmaking through dust collection and water washing. Because gas mud contains a lot of iron and carbon (1 / 4 to 1 / 3 of iron and carbon content respectively), gas mud can be used as a good iron-making raw material for recycling, which can save some coal resources At the same time, it can greatly reduce the cost of gas ash transportation and storage, and avoid serious environmental pollution caused by the disposal of gas ash, which has far-reaching economic and environmental significance. [0003] Usually, iron and steel enterprises use the collected gas sludge as sintering raw materials for recycling wit...

AI Technical Summary

Problems solved by technology

The main problems in the treatment of zinc-containing dust in the rotary hearth furnace are the high exhaust gas temperature and low thermal efficiency, and at the same time, zinc vapor condensation blocks the exhaust channel, resulting in unsmooth production;

[0007] (3) Oxycup dust treatment process: Oxycup shaft furnace adopts internal coal blending briquettes. In order to ensure sufficient strength, cement needs to be used as a binder. The advantages of the shaft furnace are high thermal efficiency, sufficient reduction of metal oxides, and high metal recovery rate. The disadvantage is that the coke ratio is high (3 times that of ordinary blast furnace ironmaking), the utilization factor is low, and the content of S and P in molten iron is high

[0009] 1) It affects the life of the blast furnace. Zinc oxide is reduced under the action of reducing gas to form zinc vapor that penetrates into the furnace lining, causing abnormal expansion and embrittlement of the furnace lining;

[0010] 2) Affect the forward movement of the blast furnace, zinc vapor weakens the metallurgical properties of coke and ore, deteriorates the gas permeability of the material column, and produces furnace nodules and suspended materials

[0027] 1) The residual carbon and residual zinc content in the treated slag is relatively high, resulting in a waste of carbon resources and an increase in production costs;

[0028] 2) The treatment of zinc oxide in the gas mud is not thorough, and after being added to the blast furnace as a raw material, it will still cause great harm to ironmaking equipment and ironmaking production;

[0029] 3) The gas peat dry and / or coke mixture must be pelletized and dried before reduction, and the production cost is high;

[0030] 4) The dry coal and / or coking coal added to the gas mud has a high impurity content, which is likely to cause ring formation in the rotary kiln, prolong the production period of the kiln, and further increase the production cost;

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