Clean metallurgic comprehensive utilization method of iron vitriol slags

Abstract

The invention relates to a clean metallurgic method for treating iron vitriol slags produced during the processes of smelting zinc and removing iron by a wet method and recovering the valuable metals. The method comprises the following steps: 1) intermediate temperature roasting the waste slags to decompose iron vitriol and zinc ferrite in the slags; 2) selectively leaching the roasted iron vitriol dregs by ammonium chloride and an ammonia aqueous solution to obtain the leachate containing zinc, copper, lead, cadmium, silver and the like as well as leached slag containing iron and arsenic; 3) reducing and recovering the copper, lead, cadmium and silver in the leachate by zinc powder to obtain a zinc ion-rich ammonium chloride solution; 4) extracting zinc in the ammonium chloride solution by P204, back extracting by sulfuric acid to the solution, carrying out electrodeposition to obtain cathode zinc with high purity; 5) leaching the leached slags in the step (2) by a sodium hydroxide solution to obtain the alkali leached slag with full detoxification which can be taken as high quality low ferrosilicon ore concentrate or an ironmaking raw material. The method can effectively recover the valuable metals in the iron vitriol slags, the treatment process is clean, and the comprehensive utilization method can effectively solve the stock and pollution problems of iron vitriol dregs.

Description

technical field [0001] The invention belongs to the field of metallurgical hazardous solid waste treatment, in particular to a method for comprehensively utilizing jarosite slag in a clean metallurgical method, which can also be used to treat other types of jarosite slag containing heavy metals. Background technique [0002] my country is currently facing serious heavy metal pollution problems, and non-ferrous lead and zinc smelting is a key industry for the prevention and control of heavy metal pollution. There are many associated elements in sphalerite resources in my country, and the ore types are complex, often associated with toxic and harmful impurities such as cadmium, lead, arsenic, and mercury, which increases the difficulty of recycling during the smelting process. At present, zinc smelting methods in the world are mainly divided into two categories: fire method and wet method, and 80% of the world's total output is produced by wet method. The traditional zinc hyd...

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Problems solved by technology

For example, the patent EP 1098999-A1 proposes that after roasting, leaching with water, and then recovering valuable metals through neutralization precipitation, sulfide precipitation, ion exchange or extraction, the process is simple, but the disadvantage is that the recovery rate of silver and lead is low; patent US2004118248- A1 proposes that the jarosite slag is first treated with alkali, and then neutralized with acid to dissolve and recover valuable metals. The process can be adapted to the treatment of complex multi-metal waste residues with different properties, but unavoidable in the acid leaching process. The dissolution of iron will produce iron waste slag containing heavy metals when iron is removed again; the patent CN1221800 proposes to roast the alum slag, after leaching, centrifugal extraction and separation of indium and iron to recover indium, the disadvantage of which is the dissolution of a large amount of iron. It is very difficult to recover a large amount of iron slag and heavy metal ions in subsequent iron removal; patent WO8803911-A proposes to use CaCl under high temperature, high acid and high pressure 2 The method of leaching valuable metals in the alumina slag achieves a good metal recovery rate and also inhibits the dissolution of iron, but the disadvantage is that it uses high temperature, high acid and high pressure leaching, and the cost is relatively high

In order to comprehensively recycle and utilize the iron resources in the jarosite slag, the patent KR8902856-B proposes to mix the iron hydroxide and activated carbon after roasting, water immersion, neutralization and precipitation of the jarosite slag to make a hydrogen sulfide adsorbent. The key problem is that The purity of the ferric hydroxide product is not high, and other resources in the jarosite slag have not been effectively recovered; the patent CN101407355A proposes acid leaching the jarosite slag to recover valuable metals, and the leaching residue is mixed with sulfuric acid under microwave radiation, and then water and Iron substances, oxidized to convert iron into trivalent, hydrolyzed to produce polyferric sulfate, the key problem of this process is that the product purity and the recovery rate of other heavy metals are not high, etc.

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