A method for reducing and self-sulfiding roasting pretreatment jarosite slag

Abstract

The invention discloses a method for pretreatment of jarosite slag by reducing self-sulfidation roasting, which comprises the following steps: (1) mixing jarosite slag and a reducing agent, and performing solid-solid reduction and sulfur-fixing roasting on the obtained mixture, so that jarosite The metal sulfate in the slag is reduced to metal sulfide to obtain a reduced roasted product; (2) The reduced roasted product obtained in step (1) is subjected to reduction sulfurization roasting, so that the iron sulfide and heavy metal oxide in the reduced roasted product react to form Elemental iron and heavy metal sulfides reduce iron oxides to metallic iron, and at the same time realize the aggregation and growth of Fe and heavy metal sulfides to obtain reduced sulfide roasted products. The pretreatment method can realize the fixation of sulfur, the sulfidation conversion of heavy metals and the metallization of iron to the greatest extent, and facilitates the recovery of valuable components through flotation and magnetic separation respectively.

Description

technical field [0001] The invention relates to the technical field of metallurgy, in particular to a method for reducing and self-sulfiding roasting pretreatment of ferrite slag. Background technique [0002] Jarosite slag is the precipitated iron slag obtained by using the Jadosite method to remove iron in the smelting process of manganese, zinc, copper, nickel, cobalt, etc. Fe 3+ The iron vitriol crystals formed by ion precipitation have the largest yield in the zinc smelting process. Since Liuzhou Nonferrous Metals Smelter in Guangxi took the lead in industrial application of jarosite iron removal in my country in 1985, there have been more than ten manufacturers such as Shaanxi Shangluo Smelter, Northwest Lead-Zinc Smelter and Guangxi Laibin Smelter, etc. who have adopted the jarosite method. Carry out zinc smelting to remove iron. At present, the stock of iron slag in my country exceeds 30 million tons, and it is increasing at a rate of more than 1 million tons per y...

AI Technical Summary

Problems solved by technology

Due to the low sulfur content of alum slag during desulfurization and roasting in this process, the low concentration of SO produced during desulfurization and roasting 2 Gas needs to be enriched with ionic liquid to meet the requirements of acid production, and the cost is high; the reduced pellets need to be cooled, magnetically separated and then melted at high temperature, the process is complicated, energy consumption is high and costly, and the process of reduction and volatilization Because Cu, Ag, Ni, Co and other elements that are difficult to volatilize enter into the reduced iron, a large amount of valuable metals are lost, and the recovery of valuable metals is insufficient

[0005] The Chinese patent with publication number (CN 106544460 A) discloses a method and system for processing jarosite slag. The method is to mix the jarosite slag with a carbonaceous reducing agent and additives and send them into an annular radiation furnace, and then bake them separately. Dry area, decomposition area, and reduction area realize the drying, desulfurization, reduction and volatilization of zinc and lead, and metallization of iron slag. The roasted product is magnetically separated to obtain iron concentrate. The process is short and the energy consumption is low. But there is also a low concentration of SO 2 The problem of difficulty in flue gas treatment. In addition, since the decomposition of iron vitriol is carried out under a weak reducing atmosphere, the removal rate of sulfur in the decomposition zone is only about 70%, so the volatilization effect of lead and zinc during reduction and volatilization is poor

[0006] Generally speaking, the existing pyrolysis process has certain application when the content of elements such as In in the alumina slag is high, but due to the limitation of the actual process, the desulfurization is not complete, the content of heavy metal sulfide is high, and the magnetic separation process cannot be effectively separated. , the taste of iron is not high, so it cannot effectively solve the resource utilization of iron, the efficient recovery of other metals and the process of SO 2 , secondary tailings and leachate pollution, etc., so it has not been widely promoted

[0007] The existing technology has carried out the pulverized coal reduction roasting-magnetic separation test research on the iron slag, and the magnetite with an iron content of 58.72% is produced, the metal zinc is dispersed in the concentrate and tailings, and the sulfur is in the roasting gas, magnetic Concentrated ore and magnetic separation tailings are dispersed. This method has failed to solve the resource utilization of iron and zinc, and has produced SO 2 Tail gas and magnetic separation tailings secondary pollution, no application prospects

[0008] Liu Chao and others have studied the microwave heating sulfate roasting technology. Under the optimized sulfate roasting and water leaching process conditions, the leaching rates of Fe, Zn, In, Cu, Ag and Cd reached 89.4%, 80.7%, 85.1%, 90.7%, respectively. %, 61.3% and 48.8%, while Pb is basically PbSO 4 In this method, iron and other valuable metals are simultaneously leached, and it is difficult to completely separate iron from other metals in the solution, and there is no effective way to recycle iron, so the application prospect is limited.

[0009] Although the treatment technology of the jarosite slag has been widely studied, there is no economically feasible treatment method that can realize the resource recovery of iron and other valuable metals without causing secondary pollution, and the huge amount of jarosite slag has hardly been effectively treated. And all stockpiles have seriously restricted the development of zinc and several other major metal industries.

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