Method and system for direct reduction of wet zinc smelting slag

Abstract

The invention discloses a method and system for direction reduction of wet process zinc smelting slag. The method includes the steps that the dry zinc leaching slag is mixed with coal and limestone, and a mixture is obtained; the mixture is subjected to first pelletizing treatment, and first mixed material agglomerate is obtained; the first mixed material agglomerate is wrapped in calcium oxalate powder to be subjected to second pelletizing treatment, and second mixed material agglomerate with a calcium oxalate outer layer is obtained; the second mixed material agglomerate is subjected to reduction roasting treatment, and smoke containing silver, lead, zinc and indium and a metalized pellet is obtained; and the metalized pellet is subjected to ore grinding magnetic separation treatment, and a metal iron product is obtained. According to the method, the limestone is added to the ingredients so that reduction of iron can be promoted, the slag melting point is reduced, volatilization of lead, zinc and silver is promoted, and the sulfur content of the iron product is reduced; and meanwhile, pelletizing is conducted in a step-by-step manner, the calcium oxalate outer layer is formed on the surface of the second mixed material agglomerate, escaping of SO2 in the second mixed material agglomerate is reduced, and melting of the second mixed material agglomerate is effectively prevented.

Description

technical field [0001] The present invention relates to a method of direct reduction of hydro-process zinc smelting slag and a system for implementing the aforementioned method of direct reduction of hydro-process zinc smelting slag. Background technique [0002] The large amount of lead and silver slag produced in the zinc hydrometallurgy process generally contains scattered metals, precious metals and other valuable metals. The recovery processes for these metals are generally divided into two types: direct method and indirect method. The direct method uses lead and silver slag as the main raw material, and selects an appropriate process to recover the valuable metals in the slag. [0003] Hydrometallurgy is currently the most widely used method of zinc smelting in the world, and the output of electric zinc produced by this method accounts for about 85% of the total zinc output. Zinc hydrometallurgy includes conventional leaching method, hot acid leaching jarosite method,...

AI Technical Summary

Problems solved by technology

By leaching the kiln slag again, the acid consumption is huge

In addition, 92-94% zinc, 82-84% lead and about 10% silver can be recovered through fuming volatilization in the rotary kiln, and the volatilization rate of indium is less than 80%.

The advantage of the rotary kiln method is that the volatile recovery rate of lead and zinc is high, but the disadvantages are also very obvious

First of all, the silver recovery effect of the rotary kiln method is very poor, most of the silver cannot be recovered, 70% remains in the volatilized kiln slag, and the recovery rate of further silver selection from the kiln slag is 50-65%, resulting in a large amount of precious metals drain

For ~22% of the iron in the zinc slag also enters the kiln slag, and through magnetic separation, the grade of the iron concentrate can reach more than 68%, but the sulfur content is as high as 3%, and it is difficult to sell the iron concentrate

[0005] Therefore, the existing zinc hydrometallurgy method needs to be improved

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