SU759607A1 - Method of leaching oxidized zinc-containing material - Google Patents

Description

The invention relates to the field of non-ferrous metallurgy, mainly to zinc metallurgy, and can be used for hydrometallurgy processing of calcined zinc concentrates and similar materials - gelcoats, slags containing zinc mainly in the form of oxide. | 0

There is a method of leaching oxidized zinc-containing material in the presence of an oxidizing agent with neutralizing the solution from leaching to a pH below pH of hydration of zinc sulphate.

By a known method, Manganese (IV) oxide is used as an oxidizing agent. The method allows, simultaneously with leaching of calcined zinc concentrate, to purify the solution from iron to its residual concentration of 30-50 mg / l as a result of oxidation of iron (II) in solution 25 followed by hydrolytic precipitation of iron (III). At the same time impurities of arsenic, antimony, silicon dioxide and partially copper are precipitated simultaneously with iron from the solution. .thirty

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However, the use of a known method for leaching oxidized zinc-containing materials, especially velcroxides, leads to contamination of zinc sulfate solution with manganese sulfate (IG), which accumulates in solutions from leaching to a concentration of 20 g / l and more. The production of zinc vitriol from such solutions requires special purification of solutions from manganese, and the electrolytic production of zinc from solutions containing manganese sulphate in such quantities is characterized by an increased consumption of electrical energy compared to current results of the operation of zinc electrolyte plants.

The aim of the invention is to reduce the content of iron and manganese in the zinc sulphate solution.

This goal is achieved by the use of lead (IV) oxide as an oxidizing agent.

Lead (IV) oxide is a stronger oxidizing agent in an acidic environment than manganese (IV) oxide. Therefore, in the process of sulfuric acid leaching of oxidized zinc containing ma ^^ Iyaoisazhg.-1

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Thermal lead oxide (IV) oxidizes ferro-ions more intensively:

+ 2Гё50 ₄ ё 2Н ₂ 50 ₄ - РЬ50 ₄ +

+ ₄ (50 ₄ ) _a + 2H ₂ 0.

The product of the interaction of the oxidizing agent with a dirty solution _

zinc sulfate - lead (II) sulfate - ’

I’m doing yellowing with a blend: its solubility in 100 g of water at 20 ° C is 4.1 · Ί0 "® g,

'and in sulphate solutions, it is significantly reduced. Therefore, the lead oxide (IV) in the leaching of oxide-GHYYH 'centers, ^^ p1kg ^ th'x'1аа ^'e'riа ^ in the Ίβ ¹ 'sulfuric acid solution practically does not go into solution and unlike 15

(preparation of zinc sulphate solutions containing less impurities.

Another difference is that, in using an oxidant-dissolved svinetssoderzhaschieelektrody, pre- ^20: preliminarily subjected to anodic oxidation in the sulphate solution.

Electrochemical oxidation of lead is one of the methods for producing lead (IV) oxide. In 5 ETdi S 25, lead oxide (IV) forms a film on the surface of lead-containing electrodes. In the process of sulfuric acid leaching in the presence of such electrodes, lead (IV) oxide is converted to lead (II) sulfate, which is released on the surface of the electrodes and practically does not convert to oxidized zinc-containing materials. So about-

At once, the use of lead-containing electrodes for leaching minimizes the irretrievable loss of the oxidizing agent. '

With repeated anodic oxidation of electrodes coated with a layer of lead (II) sulfate, the latter is converted into lead (IV) oxide (activation of electrodes). This process is repeatedly carried out during the operation of lead-acid batteries.

In zinc electrolyte production, lead-containing electrodes can be activated simultaneously with electrolytic release of zinc from sulphate solutions. In this case, lead anodes of zinc electrolysis baths should be periodically placed in zinc cinder leaching reactors, and then, in a deactivated state, returned to zinc electrolysis.

PRI me R 1. Calcined zinc concentrate of the composition,%: zinc 55.8 copper 1.71, cadmium 0.14, iron 12.1, leached into 800 ml of solution of composition, g / l: zinc “41, 4, sulfuric acid 150, at 80 ° C and stirring with a mechanical stirrer at a rate of ·

50b rpm Before starting leaching, various oxidizing agents are added to the pulp. The consumption of cinder coc. Favlyayet 180 g, the duration of leaching - 90 minutes Other leaching conditions and its results are given in Table. one.

Table 1

Effect of oxidizing agents on leaching zinc calcine.

Oxidizing agent ph Concentration, g / l Si | Re | Mp Lead Oxide (IV) . (electrode) 5.23 0.71 0.02 0.10 Manganese (IV) oxide (consumption 3.0 g). 4.98 1.57 0.05 2.28 Without agent 5.10 1.27 0.3 g 0.11

Note: a) an electrode made of lead alloy with 1% silver, its working surface is equal to 2.0 dm ^_2;

b) electrcGd is preliminarily subjected to anodic oxidation in a plant ..... ^{: a} zinc sulphate thief with a zinc concentration of 140 g / l for 40 min at an anodic value

.......... current density 350 A / m ² .

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Example '2. Calcined zinc concentrate composition,%: zinc 55.8, copper 1.71, cadmium 0.14, iron 12.1, leached in 800 ml of the composition solution, g / l: zinc 39.3, sulfuric acid 151 , at 80 ° C and stirring with a mechanical stirrer at a speed of 500. rpm for 60 minutes in the presence of an electrode made of lead alloy with 1% silver. The working surface of the electrode is 2.0 dm.

ten

The consumption of calcined zinc concentrate is 160 g, it is loaded into the reactor in portions: first 80 r, after 10 min from the start of the experiment 40 g, ₍ 30 min from the start of the experiment, another .40 g

The electrode is preliminarily subjected to anodic oxidation in a zinc sulphate solution with a zinc concentration of 140 g / l with an anodic current density of 350 A / m ² .

Conditions leaching and its results are presented in table. 2

Table 2 The effect of pre-anodic oxidation

Lead Electrode Leaching Results

Duration of anodic oxidation electrode, min The concentration of iron (II), mg / l, with the duration of leaching, min ph of the final solution ten —Ω about | 40 [60 0 519 787 982 988 2.27 ten 415 537 677 671 2.14 20 378 433 561 549 2.15 thirty 372 354 445 421 2.15 40 354 329 409 336 2.13

naaya acid 150 at 80 ° С and stirring with a mechanical stirrer at a speed of 200 rpm. The leaching conditions and its results are given in table. 3

Table 3

Comparison of leaching of zinc cinder

Example 3. Calcined zinc concentrate composition,%: zinc .55.8, copper 1.71, cadmium 0.14, iron 12.1, leached in 800 ml of the composition solution, g / l: zinc 41.4, sulfur

----_ - --- - - - - - - - —— —----- - -----— - ——7-g- Conditions leaching results leaching Availability WITH. s The concentration of iron (P), mg / l, PH electrode R min at time, min of course ------------- HIS Τ Ι T + t + T + t + growing +10 + 20 + 30 + 40 the thief __ „„ „ __-one_______-

Without electrode 170 90 403 366 329 305 287 4.85 With electrode 170 90 31 24 24 12 12 4.85

60 933 445

317 220 171

5.18

Bee Electrode 180

With electrode 180

60 244 67 67 55

49 5.36

Note: a) legend: C is the consumption of calcined zinc concentrate, T is the duration of leaching,

b) the electrode is made of lead alloy with 1% silver, the working surface of the electrode is 2.0 dm ² ,

c) the electrode is preliminarily subjected to anodic oxidation in a solution of zinc sulphate with a zinc concentration of 140 g / l for 40 m ^ at an anodic current density of 350 A / m.

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Using the proposed method for leaching zinc-containing materials _in the oxidised tsinkelektrolitnom production provides over existing methods "following advantages: 5

elimination of the consumption of manganese ore (pyrolusite) used in modern zinc electrolyte plants for the oxidation of impurities (mainly iron) in the leaching process;

obtaining more pure solutions of zinc sulphate by impurities of manganese (0.1 g / l and less instead of 5 g / l. and more by a known method) and iron (10-12 mg / l instead of 30-50 mg / l ' ⁵ by the known way) ί

_OTS in the _{effect of} contamination of the resulting solution of zinc sulfate by the products of the interaction of the oxidizing agent with the sulfate solution; 20

an increase in extraction of zinc by 3-5% and its accompanying valuable components (first of all, cadmium by 5-6%) from the calcine during its sulfuric acid leaching, since using the method in 25 it becomes possible to conduct leaching in a more rigid mode (for example, with the initial the acidity of the solution is 140-150 g / l instead of 50-60 g / l, like, 30 it is accepted in modern zinc plants) without danger of increasing

contamination resulting from the leaching of a solution of zinc sulfate specified impurities.

All of the above ultimately provides for obtaining higher quality products and increasing the complexity of the use of mineral raw materials. .

Claims (2)

Claim 1. The method of leaching an oxidized zinc-containing material in the presence of an oxidizing agent with neutralizing the solution from leaching to a pH less than the pH of hydrate formation of zinc sulfate, in order to reduce iron and manganese in zinc sulphate solution, lead oxide (I V) is used as an oxidizing agent 2. The way pop. 1, characterized in that lead-containing electrodes, previously subjected to anodic oxidation in sulphate solution, are used as an oxidizing agent.