CN106868319B - A method of obtaining high purity tellurium from the immersion liquid of alkali containing arsenic - Google Patents

Abstract

A method for obtaining high-purity tellurium from an arsenic-containing alkaline leaching solution. The invention relates to an arsenic-containing, tellurium-lead-tin-containing alkaline leaching solution. The alkaline immersion solution is neutralized by sulfuric acid, the neutralization solution is selectively reduced, and the reduced solution is pure sodium arsenite solution, which is used as a raw material for arsenic purification of zinc sulfate solution to remove cobalt and nickel, and the reduction slag and neutralization slag are reduced by hydrogen , Vacuum distillation to obtain more than 99.999% high-purity tellurium. In the invention, tellurium is recovered from high-arsenic solution, and pure sodium arsenite solution is obtained, which is used to purify arsenic salt of zinc sulfate solution and remove cobalt and nickel raw materials in zinc smelting. The invention has short process flow and high recovery rate, and solves the pollution problem in the extraction process of the traditional process.

Description

A method for obtaining high-purity tellurium from arsenic-containing alkali immersion solution

technical field

The invention belongs to the technical field of hydrometallurgy, and in particular relates to a method for obtaining high-purity tellurium from an arsenic-containing alkali immersion solution.

Background technique

Tellurium is widely used in solar cells, optical disk recording, thermoelectric refrigeration, etc., and is increasingly valued and favored by scientific and technological workers at home and abroad. Tellurium is also considered as one of the important supporting materials in the high-tech field in the 21st century. . However, tellurium began to be produced on a large scale in 1942. In recent years, with the rapid development of high-tech industries, the demand for tellurium has increased sharply. Therefore, in the case of limited tellurium reserves, it is of great significance to comprehensively recover metal tellurium from waste. During the smelting and roasting of lead and zinc, the high-arsenic and antimony fumes produced not only contain a large amount of arsenic and antimony, but also contain a small amount of tellurium. After the high-arsenic-antimony fume is treated by oxygen pressure alkaline leaching, the arsenic-containing alkaline leaching solution contains part of tellurium. How to comprehensively recover the scattered metal tellurium is a difficult problem that has not been well solved at present.

Chinese invention patent publication number CN103264997A discloses a method for extracting tellurium from low-concentration tellurium liquid. Add HCl solution to the low-concentration tellurium solution to obtain the pretreated tellurium solution aqueous phase, in which the HCl concentration is 4.5mol/L; add tributyl phosphate/kerosene organic phase according to the ratio of 1:1, shake and extract for 2 to 4 minutes, and extract The series is one level, after static separation, the loaded organic phase is obtained; the NH ₄ Cl solution is added to the aqueous phase at a ratio of 1:1 for back extraction, and the extraction is shaken for 0.5-2min. The extraction series is three levels, and the water phase is separated by standing ; The tellurium-containing aqueous phase after the above-mentioned back extraction is obtained by evaporation or precipitation. The invention adopts extraction→retraction→precipitation process to extract tellurium from tellurium-containing solution. The process is long, the operation is complicated, and the consumption of reagents is large.

Chinese Invention Patent Publication No. CN101844750A discloses a method for preparing high-purity tellurium from tellurium-containing materials. The method is to prepare high-purity tellurium through chemical treatment. The tellurium-containing material is oxidized, acid leached, and filtered to obtain crude tellurium; under the action of an oxidizing agent, the acidic solution is leached to obtain a tellurium-containing solution; a reducing agent is added to the tellurium-containing solution, heated and filtered after reaction, and again in the filtrate Add a reducing agent, react under heating, and then filter to obtain tellurium powder; dissolve the tellurium powder in an acidic solution under the action of an oxidizing agent, and then add a reducing agent to obtain refined tellurium; at 200°C to 800°C, treat the refined tellurium with hydrogen to obtain high-purity tellurium. The process of extracting refined tellurium from tellurium-containing smelting slag in the invention is long, lengthy and complicated, and the recovery period is long.

Contents of the invention

In order to solve the problems of low tellurium recovery rate and complex process flow in the tellurium-containing alkali leaching solution, the present invention proposes a method for obtaining high-purity tellurium from the arsenic-containing alkali leaching solution, comprising the following steps:

(1) Neutralization: take the arsenic-containing alkali immersion solution, adjust the pH value of the arsenic-containing alkali immersion solution to 4-6, and obtain neutralization solution and neutralization slag after liquid-solid separation, wherein the neutralization slag enters the subsequent Hydrogen reduction process;

(2) Selective reduction: pass reducing gas into the neutralization liquid obtained in step (1) for reduction. After the reduction is completed, the liquid and solid are separated to obtain a reduction liquid and a reduction slag; the reduction liquid is pure sodium arsenite The solution is used as the raw material for zinc sulfate solution arsenic salt purification to remove cobalt and nickel;

(3) Hydrogen reduction, vacuum distillation: the reduction slag obtained in step (2) and the neutralization slag obtained in step (1) are subjected to hydrogen reduction to obtain thick tellurium and lead slag, and the lead slag is used as a raw material for smelting lead. Section and a distillation section of the vacuum distillation furnace vacuum distillation, more than 99.999% of high-purity tellurium.

The scheme of the present invention is to remove lead and a part of tellurium in the alkaline immersion solution through sulfuric acid neutralization, and selectively reduce the neutralization solution, and the reduced solution is pure sodium arsenite solution, which is used for the purification and removal of arsenic salt in zinc sulfate solution. The raw material of cobalt and nickel, reduction slag and neutralization slag are hydrogen reduction and vacuum distillation to obtain high-purity tellurium of more than 99.999%, so as to realize the separation of valuable metals in the arsenic-containing alkali leaching solution, and effectively realize the resource harmless and harmless. The invention has high resource comprehensive utilization rate, wide application range of raw materials, and solves the pollution problem in the traditional extraction process.

The chemical equation of the neutralization process is as follows:

Na ₂ TeO ₃ +H ₂ SO ₄ =TeO ₂ ↓+Na ₂ SO ₄ +H ₂ O

Pb ²⁺ +SO ₄ ^2— ＝PbSO ₄ ↓

This converts the sodium tellurite in solution to tellurium dioxide which settles down.

The chemical equation of the reduction process is as follows:

Na ₃ AsO ₄ +SO ₂ ＝NaAsO ₂ +Na ₂ SO ₄

TeOOH ⁺ +2SO ₂ +2H ₂ O＝Te↓+5H ⁺ +2SO ₄ ^2-

Pb ²⁺ +SO ₂ +H ₂ O＝PbSO ₃ ↓+2H ⁺

This makes it possible to obtain a pure sodium arsenite solution while recovering the tellurium present in the solution as TeOOH ⁺ .

Then, the neutralized slag and the reduced slag are subjected to two processes of hydrogen reduction and vacuum distillation to obtain 99.999% high-purity tellurium. The method not only solves the problem of tellurium recovery in the arsenic-containing tellurium dust, but also utilizes the arsenic as a resource.

The arsenic-containing alkali leaching solution used in the present invention is mainly the leaching solution obtained by treating arsenic-containing fumes with a caustic solution. Specifically, the main components of the arsenic-containing alkali immersion solution are As 1-60g/L, Pb 50ppm-800ppm, Sn 2ppm-200ppm, Te 10-500ppm, and NaOH 10-120g/L.

Preferably, in step (1), the neutralization temperature is from room temperature to 80°C.

Specifically, the operation of step (1) is: under the conditions of room temperature to 80°C and a stirring speed of 100r/min-300r/min, acid (such as sulfuric acid) is added to the arsenic-containing alkali immersion solution to adjust the pH value of the solution to 3-300r/min. 6.

Preferably, in step (2), the reducing gas is SO ₂ .

Specifically, the operation of step (2) is: under the condition of room temperature to 90° C., aeration is performed at a rate of 0.5-5 L/min for 0.5-4 hours.

Preferably, the hydrogen reduction temperature in step (3) is controlled at 550°C-650°C.

Preferably, the temperatures of the two condensation sections of the vacuum distillation in step (3) are 290°C-310°C and 310°C-330°C respectively, and the temperature of the distillation section is controlled at 500°C-550°C.

Preferably, the degree of vacuum in step (3) is controlled to be 0.1-5Pa.

Advantage and positive effect of the present invention:

1. The arsenic-containing alkali immersion solution used in the present invention is mainly the solution containing arsenic and tellurium obtained when caustic soda solution is used to process arsenic-containing smoke. The arsenic content in the solution is high, and more than 95% of tellurium is enriched in the solution, but there is no relevant report on the recovery of tellurium from the high-arsenic solution and the utilization of arsenic. ;

2. After the tellurium in the soot is effectively dissolved and leached, the present invention selects to selectively separate tellurium and lead from the leaching solution, which is based on the characteristics of arsenic, tellurium, lead and tin elements in the leaching solution, so that tellurium, lead, Selective reduction of tin is removed from the solution, and the content of Te in the purification slag reaches more than 55%;

3. The present invention has low labor intensity, short processing time and good operating environment;

4. No secondary pollutants are generated during the preparation process, and arsenic can be enriched in the reduced solution, and arsenic is used as a raw material for purifying cobalt and nickel with zinc sulfate solution, which is also of great significance in terms of environmental protection;

5. The removal rate of tellurium in the present invention is above 99%, not only treating the arsenic-containing tellurium alkali immersion solution, but also obtaining pure NaAsO ₂ , especially the recovery rate of tellurium is as high as 92%.

6. The reasonable process matching of the present invention, through strict control of the condition parameters in each process, tellurium and arsenic are recovered and effectively utilized, achieving the goals of environmental protection, economy, energy saving, and high resource utilization rate, and realizing the resource utilization of arsenic and harmless, and basically no three wastes are discharged in the whole process, all resources are utilized with maximum efficiency, and the obtained products are convenient for subsequent treatment and processing, so the present invention has the advantages of environmental protection, economy, energy saving, and high resource utilization rate.

Description of drawings

Fig. 1 is a flow chart of obtaining tellurium metal from solutions containing arsenic, tellurium, lead and tellurium.

Detailed ways

The following are examples of the present invention.

Example 1:

Taking the alkaline immersion solution in the experiment as an example, the concentration of main elements in it is Pb 706.67ppm, Sn 29.02ppm, Te134.56ppm, As 28.29g/L, and the following steps are used for treatment:

(1) Neutralization: Add H ₂ SO ₄ to the alkaline immersion solution at a temperature of 40°C and a stirring speed of 200r/min to adjust the pH of the alkaline immersion solution to 5, and separate the liquid and solid to obtain a neutralization solution and neutralization solution. and slag; the resulting neutralized slag enters the subsequent hydrogen reduction process;

(2) Selective reduction: The neutralization solution obtained in step (1) enters the selective reduction process, and SO ₂ is introduced into the neutralization solution. 2h. Obtain sodium arsenite solution and reduction slag after reduction finishes;

After testing: the content of each element in the reducing solution is: Pb 2.86ppm, Sn 0.79ppm, Te 1.08ppm, As27.01g/L. The calculated removal rates of Pb and Te are: Pb 99.59%, Te 99.20%.

(3) Hydrogen reduction and vacuum distillation: the reduction slag obtained in step (2) and the neutralization slag of step (1) enter the hydrogen reduction process and the vacuum distillation process, and the reduction slag is reduced at 600 ° C to obtain 99.9% Te and Lead slag, lead slag is used as raw material for lead smelting; then 99.9% Te is vacuum distilled in a vacuum distillation furnace with two condensation sections and one distillation section. The temperature is 510°C, the vacuum degree is 2Pa, and 99.999% high-purity tellurium is obtained by distillation.

Example 2:

Take the alkaline immersion solution in the experiment as an example, in which the main element concentrations are Pb 647.26ppm, Sn 68.59ppm, Te238.45ppm, As 38.46g/L, and the following steps are used for treatment:

(1) Neutralization: Add H ₂ SO ₄ to the alkaline immersion solution at a temperature of 80°C and a stirring speed of 150r/min to adjust the pH of the alkaline immersion solution to 4, and separate the liquid and solid to obtain a neutralization solution and neutralization solution. and slag; the resulting neutralized slag enters the subsequent hydrogen reduction process;

(2) Selective reduction: The neutralization solution obtained in step (1) enters the reduction process, and SO ₂ is introduced into the neutralization solution under the control conditions of gas flow rate of 3 L/min, temperature of 90°C, and aeration time of 3 hours. Obtain sodium arsenite solution and reduction slag after reduction finishes;

After testing: the content of each element in the reducing solution is: Pb 2.43ppm, Sn 0.98ppm, Te 1.45ppm, As37.89g/L. The calculated removal rates of Pb and Te are: Pb 99.62%, Te 99.39%.

(3) Hydrogen reduction and vacuum distillation: the reduction slag obtained in step (3) and the neutralization slag in step (1) enter the hydrogen reduction process and vacuum distillation process, and the reduction slag is reduced at 650 ° C to obtain 99.8% Te and lead Slag and lead slag are used as raw materials for smelting lead; then 99.7% of Te is vacuum distilled in a vacuum distillation furnace with two condensation sections and one distillation section. The temperature is 530°C, the vacuum degree is 5Pa, and the high-purity tellurium of more than 99.999% is obtained by distillation.

Example 3:

Taking the alkaline immersion solution in the experiment as an example, the concentration of main elements in it is Pb 547.85ppm, Sn 67.43ppm, Te164.27ppm, As 19.44g/L, and the following steps are used for treatment:

(1) Neutralization: Add H ₂ SO ₄ to the alkaline immersion solution at a temperature of 40°C and a stirring speed of 100r/min to adjust the pH of the alkaline immersion solution to 5, and separate the liquid and solid to obtain a neutralization solution and neutralization solution. and slag; the resulting neutralized slag enters the subsequent hydrogen reduction process;

(2) Selective reduction: the neutralized liquid obtained in step (1) enters the reduction process, and the neutralized slag enters the hydrogen reduction process. Feed SO ₂ into the neutralizing liquid, and the control conditions are as follows: the gas flow rate is 5L/min, the temperature is 70°C, and the aeration time is 0.5h. Obtain sodium arsenite solution and reduction slag after reduction finishes;

After testing: the content of each element in the reducing solution is: Pb 3.04ppm, Sn 1.34ppm, Te 1.12ppm, As18.51g/L. The calculated removal rates of Pb and Te are: Pb 99.45%, Te 99.32%.

(3) Hydrogen reduction and vacuum distillation: the reduction slag obtained in step (3) and the neutralization slag of step (1) enter the hydrogen reduction process and vacuum distillation process, and the reduction slag is reduced at 620 ° C to obtain 99.5% Te and lead Slag and lead slag are used as raw materials for smelting lead; then 99% of Te is vacuum distilled in a vacuum distillation furnace with two condensation sections and one distillation section. The temperature is 500°C, the vacuum degree is 3Pa, and the high-purity tellurium of more than 99.99% can be obtained by distillation.

Although, the present invention has been described in detail with general description, specific implementation and test above, but on the basis of the present invention, some modifications or improvements can be made to it, which will be obvious to those skilled in the art . Therefore, the modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the protection scope of the present invention.

Claims (7)

1. a kind of method for obtaining high purity tellurium in immersion liquid from alkali containing arsenic, which is characterized in that include the following steps：

(1) it neutralizes：The immersion liquid of alkali containing arsenic, the main component of the immersion liquid of alkali containing arsenic is taken to be：As 1~60g/L, Pb 50ppm~ 800ppm, Sn 2ppm~200ppm, Te 10~120g/L of 10~500ppm, NaOH adjust the pH value of the immersion liquid of alkali containing arsenic For 4-6, after solid-liquor separation, obtains neutralizer and neutralize slag, wherein neutralize slag and enter follow-up hydrogen reduction process；

(2) selective reduction：Reducibility gas is passed through into neutralizer obtained by step (1) to be restored, after reduction, liquid is solid Reducing solution and reducing slag are obtained after separation；The reducing solution is pure sodium arsenite solution, is removed as the purification of solution of zinc sulfate arsenic The raw material of cobalt nickel；

(3) hydrogen reduction, vacuum distillation：Reducing slag obtained by step (2) carries out hydrogen reduction with neutralization slag obtained by step (1), obtains thick Tellurium and lead skim, lead skim is as refining leady raw materials, thick tellurium vacuum in the vacuum distillation furnace of condensation segment and a distilling period there are two having Distillation, obtains 99.999% or more high purity tellurium.

2. according to the method described in claim 1, it is characterized in that：When being neutralized described in step (1) extremely controlled at room temperature 80℃。

3. method according to claim 1 or 2, it is characterised in that：Reducibility gas described in step (2) is SO₂。

4. according to the method described in claim 3, it is characterized in that：In step (2), under the conditions of room temperature is to 90 DEG C, according to 0.5 The speed of~5L/min leads to SO₂Gas time is 0.5~4h.

5. according to the method described in claim 1, it is characterized in that：In step (3), the temperature of the hydrogen reduction is 550 DEG C~ 650℃。

6. method according to claim 1 or 5, it is characterised in that：In step (3), two condensation segments of vacuum distillation Temperature is respectively 290 DEG C~310 DEG C and 310 DEG C~330 DEG C, and the temperature of distilling period is 500 DEG C~550 DEG C.

7. according to the method described in claim 6, it is characterized in that：The vacuum degree of vacuum distillation is 0.1~5Pa.