Method for reversely extracting iron by adopting solvent extraction

Abstract

The invention discloses a method for reversely extracting iron by adopting solvent extraction. The method comprises the following steps that (1) an organic phase is used to extract iron in iron-containing leachate; (2) the iron is reversely extracted by using an anti-iron solution, phase separation is carried out on the iron subjected to reverse extraction, and the iron flows out together with a water phase in the phase separation process; and (3) the water phase obtained in the step (2) is filtered to obtain a ferric hydroxide solid, wherein the anti-iron solution comprises an anti-iron agent, a nucleating accelerant and water, the anti-iron agent can be one or more kinds of NaOH, KOH, ammonia water, ammonium carbonate, Na2CO3 and Ca(OH)2, and the concentration of the OH<-> is 0.2-3 mol/L. The method for reversely extracting the iron by adopting solvent extraction has the advantages of being efficient, low in cost and environment-friendly.

Description

technical field [0001] The invention belongs to the technical field of hydrometallurgy, and in particular relates to a method for back-extracting iron by solvent extraction. Background technique [0002] Solvent extraction technology has many advantages in the separation and purification of non-ferrous metals, so it has been widely used in domestic and foreign hydrometallurgical plants, and occupies an important position in modern non-ferrous metal hydrometallurgy. In non-ferrous metal solvent extraction, iron is a ubiquitous and very harmful impurity element. The presence of iron not only complicates the extraction process, increases production costs, but also brings huge environmental pressure to the factory. [0003] During the acid leaching process, iron often enters the leaching solution together with other non-ferrous metals. For factories that use solvent extraction to separate metal elements, the extraction and separation of iron and target metal elements must be ach...

AI Technical Summary

Problems solved by technology

[0004] At present, the mainstream process of stripping iron is to use high-concentration hydrochloric acid solution for multi-stage stripping. Its advantages are mature technology, stable operation, and the stripping effect of iron can generally meet the process requirements. A lot of acid mist will be produced during the process, the working environment is poor, and the acidity of the back-extraction solution is too high, and the iron concentration is low, so the treatment cost of the back-extraction solution is high, and the environmental pollution is great. In addition, the high-concentration hydrochloric acid solution is harmful to the environment. The extraction agent and equipment also have a great impact

In order to solve the difficult problem of iron stripping, some scholars and engineering technicians have researched and developed other techniques for stripping iron, which mainly contain the following: (1) On the basis of the traditional stripping iron process, the hydrochloric acid stripping liquid is The method of adding chloride in the medium to achieve the purpose of reducing the acidity of the stripping solution. Compared with the traditional method, although this method can reduce the acidity, the effect is limited. In addition, the accumulation of salt in the system will bring troubles to the production. The subsequent wastewater treatment The recovery process of iron and iron is complicated and the cost is higher; (2) back-extracting iron with oxalic acid solution

This method is better to the stripping effect of iron, and shortcoming is that the recovery process of iron and oxalic acid in the stripping solution is complicated, and the cost is high, so it is difficult to popularize and apply in industry; (3) back-extracting iron with ammonium fluoride, the shortcoming of this method Environmental pollution is big, iron recovery cost is high, waste water treatment difficulty is big, cost is high, therefore has not been adopted in industry; Enter the organic phase, or transfer the extract in the organic phase to the water phase, so that the iron stripping process is converted from an interfacial reaction to an in-phase reaction to improve the kinetic conditions of iron stripping. However, the phase transfer agent Addition will often change the properties of the organic phase, which will have an adverse effect on the extraction and phase separation process; (5) Some scholars have proposed a reduction stripping method, by adding a reducing agent, the Fe 3+ converted to Fe 2+ , which reduces the stability of iron extractants and thus facilitates the stripping of iron

However, the reduction and stripping method increases the reduction process, which makes the process complicated, reduces the production efficiency, and increases the cost of iron recovery or iron removal.

(6) back-extract iron with sodium ethylenediaminetetraacetate, the stripping agent regeneration process of this method is complex, the production efficiency is low, and the cost is high, so it is difficult to popularize and apply in industry

[0005] In short, these new methods proposed to solve the iron stripping problem have no obvious advantages in cost, operation and environmental protection compared with the traditional iron stripping process, so it is difficult to promote and apply them in industry

Therefore, so far, the problem of difficult iron stripping has not been well resolved, which has become an important factor restricting the further development of solvent extraction and hydrometallurgy technology

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