CN103911511B - Method for removing iron from zinc solution - Google Patents

Abstract

The invention discloses a method for removing iron from zinc leachate, and relates to a technology for removing iron from zinc pressure and normal pressure leachate. Aiming at the defects in the prior art, the invention adopts SO₂/O₂And (air) mixed gas is subjected to catalytic oxidation to neutralize and remove iron. The method can reduce Fe²⁺Is oxidized into Fe³⁺Thereby effectively accelerating Fe²⁺The oxidation rate. Because the method does not need to add a strong oxidant, the temperature is slightly reduced, and the consumption of air and oxygen is reduced, so the method is a high-efficiency method for removing iron from the zinc leachate.

Description

A method for removing iron from zinc solution

technical field

The invention belongs to the technical field of zinc metallurgy and relates to a method for removing iron from a zinc solution.

Background technique

Iron removal in zinc solution system is one of the main processes of zinc hydrometallurgy. The iron removal methods usually include yellow sodium (potassium) jarosite method, goethite method and hematite method.

1 yellow sodium (potassium) iron vitriol method

The reaction formula that generates jarosite is as follows:

3Fe ₂ (SO ₄ ) ₃ +14H ₂ O+Na ₂ SO ₄ ＝Na ₂ Fe ₆ (SO ₄ ) ₄ (OH) ₁₂ +6H ₂ SO ₄

The advantages of yellow soda-jasite iron removal: first, the sedimentation and filtration performance of slag is good, the slag contains low value metals, and the metal recovery rate is high; second, the consumption of chemical reagents is low.

However, the jarosite method for removing iron slag has a large amount of iron and low slag, and it is easy to absorb toxic ions such as arsenic in the solution. At present, the recycling of slag is still in the research stage in industry. The long-term accumulated jarosite slag is both The impact on the environment is also a waste of resources, which is not suitable for enterprises with strict environmental protection requirements.

2 goethite method

Goethite iron removal is divided into reduction oxidation method (VM method) and partial hydrolysis method (EZ method). The reduction-oxidation method is to reduce Fe ³⁺ to Fe ²⁺ , and then control the oxidation rate of iron so that the content of Fe ³⁺ is always lower than 1g/L, thereby forming goethite precipitation at a pH value of about 3.5. The reaction control steps in the preparation of goethite by redox method are the physical diffusion and dissolution of oxygen. At present, there are also oxidizing agents such as hydrogen peroxide instead.

The partial hydrolysis method is generally sprayed into the reaction tank containing Fe ³⁺ less than 1g/L and stirred evenly, so as to dilute the iron content. The partial hydrolysis method is easier to control than the reduction oxidation method.

3 Hematite method

The transition temperature between goethite and hydrohematite is about 150°C. Hematite with good filtration performance can be obtained by high temperature oxygen pressure hydrolysis. However, the hematite method has high temperature, high energy consumption and high requirements for equipment.

Contents of the invention

The present invention aims at the deficiencies of the above-mentioned prior art, and adopts SO ₂ /O ₂ catalytic oxidation to neutralize and remove iron. This method can reduce the activation energy of Fe ²⁺ oxidation to Fe ³⁺ , thereby effectively accelerating the oxidation rate of Fe ²⁺ . Because this method does not need to add a strong oxidant, the temperature is slightly lower and the air consumption is reduced at the same time, it is an efficient method for removing iron from zinc leachate. The specific operation steps are as follows:

(1) The zinc solution is heated to a certain temperature; a certain concentration of sulfur dioxide and air mixture is charged;

(2) adopting a certain concentration of limestone slurry to control the pH of the solution to keep for a certain period of time;

(3) After the end, the slurry is separated by filtration to obtain solution and iron slag;

(4) The solution obtains a zinc product through a follow-up process.

In some specific embodiments, the zinc solution in step (1) includes a zinc pressurized, atmospheric pressure leaching solution.

In some specific embodiments, the volume concentration of SO ₂ in the mixed gas of sulfur dioxide and air in step (1) is 0.5-5%.

In some specific embodiments, the temperature in step (1) is 30-90°C.

In some specific embodiments, the pH value of the solution in step (2) is 3.5-5.0.

In some specific embodiments, the iron removal time described in step (2) is 0.5-8 hours.

The present invention proposes a method for efficiently removing iron from zinc leaching solution, and its advantages are:

(1) The iron removal temperature is lowered, and the iron removal time is shortened.

(2) Reduce the energy consumption of the workshop and improve the efficiency of the enterprise.

detailed description

Example 1

The Fe content of the zinc pressurized leaching solution in a factory is about 8g/L after reduction. Take 500ml and heat it to 80°C. _The pH value of the solution is 3.5. %, the iron removal time is 5h, and the solution contains Fe<0.02g/L after iron removal.

Example 2

_The Fe content of the zinc pressurized leaching solution of a factory in China is about 8g/L after reduction. Take 500ml and heat it to 90°C. After 8 hours, the solution contains Fe<0.01g/L after iron removal.

Example 3

_The Fe content of the zinc pressurized leaching solution in a certain factory is about 8g/L after reduction. Take 500ml and heat it to 80°C. 1h, the solution contains Fe<0.05g/L after iron removal.

Claims (2)

1. the method removing iron from zinc lixiviating solution, it is characterised in that comprise the following steps:

(1) zinc solution is heated to 30～90 DEG C, is filled with SO₂Volumetric concentration is 0.5～the sulfur dioxide of 5% and air Mixture；

(2) using certain density lime stone serum to control solution ph is 3.5～5.0, keeps 0.5～8h；

(3), after terminating, ore pulp is separated by filtration and obtains solution and scum；

(4) solution obtains zinc product by subsequent technique.

Method the most according to claim 1, it is characterised in that zinc solution described in step (1) includes that zinc pressurizes, often Pressure leachate.