Smelting method and device for molten oxidized lead slag

Abstract

The invention discloses a smelting method and device for molten oxidized lead slag. The smelting method comprises the following steps of: enabling high-lead slag melt obtained by oxidization and smelting of a lead sulfide concentrate melting pool to flow into a rectangular reduction furnace through a chute, spraying oxygen-enriched air into molten high-lead slag melt through air openings at two side walls of the rectangular reduction furnace, and adding coal granules or coke granules from a feeding port arranged at the top of the reduction furnace; under strong stirring of the oxygen-enrichedair, fully mixing the coal granules or the coke granules with the high-lead slag for reaction, realizing the cyclic operation of feeding, reduction, deslagging and refeeding of molten high-lead slag in the reduction furnace of the melting pool, heating and stirring a stagnant slag layer in the melting pool by a temperature rising port arranged at the side wall of the reduction furnace at a certain time interval, and after reduction, producing crude lead, flue gas, fume and reduced slag. The smelting method and device have the advantages that the flue-gas amount is less, and the energy-saving effect is obvious; and the amount of lead in the reduced slag is reduced and the recovery rate of the lead in the reduction process is high.

Description

technical field [0001] The invention relates to a pyrometallurgical process in the field of metallurgy, in particular to a method for efficiently reducing lead from molten lead oxide slag and a device for realizing the method. Background technique [0002] The current main smelting process of lead sulfide concentrate is oxygen bottom blowing-blast furnace reduction smelting, which has been widely used in my country. However, in this process, the high-temperature molten lead oxide slag (also known as high-lead slag) produced from oxygen bottom-blown oxidation smelting needs to be cast and cooled into blocks by casting slag system, and the block-shaped high-lead slag is put into the blast furnace again Using coke to heat, melt and reduce lead results in waste of energy and increased costs; at the same time, due to the dense structure of massive high-lead slag and the relatively low temperature of blast furnace reduction, the reduction of lead in high-lead slag is not complete,...

AI Technical Summary

Problems solved by technology

However, due to the use of air in the reduction process, the amount of flue gas in the smelting process is large, the energy consumption is high, and the amount of flying dust and smoke is large; the high-lead slag only flows through the hot coal seam (or coke layer), and the two are not fully mixed, resulting in high The reduction effect of lead slag is poor

Invention patent "method and device for direct lead smelting in molten pool smelting" (patent number 200710127659.3), the technical solution adopted is to inject oxygen and natural gas (or coal gas), and at the same time add carbon particles to the liquid surface of the high lead slag through the feeding port of the melting pool reduction furnace, and reduce the lead in the high lead slag under the joint action of oxygen, natural gas (or gas), and carbon particles; In the process, not only oxygen but also natural gas (or coal gas) are used, and carbon particles are used as a reducing agent at the same time. The overall energy consumption is relatively high. Since oxygen is injected from the bottom of the reduction furnace, it will interact with the molten lead deposited on the bottom of the furnace. The body is first contacted and then sprayed into the high-lead slag melt, resulting in a higher lead content in the reduced final slag

Invention patent "method and device for smelting molten lead oxide slag" (patent number 200510200331.0) reduces the molten lead oxide slag in a vertical side-blowing furnace, with a smoke exhaust port and a flux inlet on the top of the furnace, and a lead oxide slag inlet on the top The side wall of the furnace body, the furnace wall on one side of the lower furnace body is provided with a nozzle inlet, and the other side is provided with a slag outlet, and the oxygen-enriched air with an oxygen concentration of 21-40% and a reducing agent (powdered coal, natural gas, coal gas or liquefied petroleum gas) ) into molten lead oxide slag to reduce lead through nozzles; but oxygen-enriched air and reducing agent need to be injected through special nozzles with complex structures, only one side of the reduction furnace is equipped with nozzles, and the stirring intensity of the melt in the furnace is low , the oxygen concentration of the oxygen-enriched air used is low, resulting in a large amount of flue gas and high energy consumption

The disadvantage of this design is that the slag layer below the tuyeres is in a non-flowing state. As a result, the slag layer gradually becomes viscous and the delamination conditions of lead and slag deteriorate; If the feeding time in the middle is too long, a similar phenomenon will also occur.

Due to the inability to heat the immobile slag layer, when the slag layer is viscous to a certain extent, the reduced metallic lead melt may not be able to pass through the slag layer, eventually causing the accident that the copper water jacket is eroded and damaged by the metallic lead melt

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