CN114933285B - Method for selectively recovering tellurium from copper anode slime - Google Patents

Abstract

The invention provides a method for selectively recovering tellurium from copper anode slime, in particular to a method for selectively leaching selenium and tellurium from copper anode slime and reducing tellurium into metal tellurium to effectively enrich valuable metals such as copper, silver, gold and the like. The invention adopts oxygen pressure alkaline leaching-Na ₂ S leaching-SO ₂ And (5) a reduction process. In the oxygen pressure alkaline leaching process, more than 99 percent of tellurium is enriched in slag, na ₂ Tellurium leaching rate in S leaching process can reach 94%, SO ₂ The recovery rate of tellurium in the reduction process can reach more than 95 percent. The method realizes the step-by-step removal of selenium and tellurium in the copper anode slime, the recovery of tellurium, the enrichment of valuable metals such as copper, silver, gold and the like, and has the advantages of high tellurium recovery rate, simple operation, no smoke pollution, low cost and the like.

Description

A method for selectively recovering tellurium from copper anode slime

technical field

The invention relates to the field of hydrometallurgy, in particular to a method for recovering tellurium from copper anode slime.

Background technique

Tellurium is a kind of scattered metal, which enjoys the reputation of "the vitamin of modern industry" and is widely used in photovoltaics, thermoelectricity, metallurgy, chemical rubber and other fields. The abundance of tellurium in the earth's crust is 1～6×10 ^-6 , and it is rarely ore-formed independently. Tellurium is often associated with other deposits, such as porphyry copper (molybdenum) deposits, copper-nickel sulfide deposits, layered sandstone copper deposits, etc. This feature determines that its main source is the by-product of other metal smelting, such as non-ferrous metals Anode slime from electrolytic refining, acid mud from non-ferrous smelting and chemical plants, etc., and copper anode slime provides about 90% tellurium in industry.

In the pyrometallurgical process of copper, copper concentrate is smelted, blown, and pyro-refined to produce blister copper. Since the purity cannot meet the industrial requirements, the blister copper needs to be electrolytically refined to produce copper of 3N grade or above. . Copper anode slime refers to the undissolved and dissolved part of the anode copper during the electrolytic refining process, such as precious metals, selenides, tellurides, lead sulfate, lead oxide, tin oxide, etc. Copper anode slime is an important source of tellurium, and the tellurium content is usually between 0.5 and 10%. At present, the methods of recovering tellurium from copper anode slime are mainly divided into semi-wet process and wet process.

The semi-wet process is widely used in industrial production. It has the characteristics of complete separation of selenium and tellurium and high recovery rate of tellurium. However, it has problems such as smoke pollution, high energy consumption, and is not suitable for small-scale production. CN103112833A discloses a method for recovering tellurium from copper anode slime. The basic process is copper anode slime sulfuration, roasting, steaming selenium-dilute acid decopper-alkaline leaching to remove tellurium-sulfuric acid neutralization and precipitation of tellurium, etc. The leaching rate is 85-90%. Although this method realizes step-by-step removal of copper, selenium, and tellurium, the leaching rate of tellurium is relatively low, and the final product is tellurium oxide. Additional processes are required to obtain elemental tellurium, which will cause lengthy processes. CN109402392A discloses a method for reclaiming tellurium by sulfated roasting-acid leaching method, copper anode slime is sulfated roasted, then leached with dilute sulfuric acid to decopper, the decoppered slag is leached by sulfuric acid, hydrochloric acid, sodium chlorate mixed solution, tellurium and Gold, platinum, palladium and other precious metals enter the solution together, and finally obtain elemental tellurium through step-by-step reduction of SO ₂ . Although the recovery rate of tellurium is high, and the purity of elemental tellurium is more than 90%, there are some problems in this method, such as a small part of tellurium entering the solution during the copper leaching process; when _SO2 reduces gold, platinum, palladium, etc., There is a small amount of tellurium reduction precipitation in the solution; and the process is too lengthy, the composition of the tellurium-containing solution is complex, and the content of chloride ions is high, which is not conducive to subsequent treatment. Some scholars also use soda roasting-alkali leaching to remove selenium-acid leaching to remove copper and tellurium to treat copper anode slime. Copper, then leached with sodium hydroxide to remove selenium, and the deselenized slag was leached with sulfuric acid to remove tellurium and copper, and the removal rates of the three were above 95%. Although this method realizes the efficient removal of selenium and tellurium in sequence, it still cannot avoid the defects of the fire process, and the alkali and acid are used alternately in the process, the consumption of reagents is large, and the process is long.

The wet process mainly includes oxidative acid leaching-reduction method, oxygen pressure alkali leaching-sulfuric acid leaching method, etc. Oxidative acid leaching-reduction method is often used for pretreatment and decopper, so that all copper and tellurium enter the solution, and then replace it with copper powder The method of recovering tellurium from the solution has the advantages of low cost, low pollution and strong applicability. CN102220489A discloses a method for reclaiming tellurium by a wet process, that is, oxygen pressure acid leaching to remove copper, tellurium and part of selenium— _SO2 reduction selenium precipitation—electrodeposition copper— _SO2 reduction precipitation precipitation, this method can remove copper in one step Copper and tellurium in anode slime, but the process is long, and it is easy to cause the dispersion of selenium, and the purity of crude tellurium is unstable, fluctuating between 75% and 92%. The oxygen pressure alkaline leaching-sulfuric acid leaching method has the advantages of high removal rate of selenium and copper and simple process. CN101775498A discloses a method for removing selenium and tellurium in copper anode slime step by step, that is, the copper anode slime is first treated with oxygen pressure alkali leaching, selenium enters the solution, tellurium and copper are enriched in the slag, and then the two are leached with sulfuric acid. The removal rate of selenium and copper in the process is higher than 95%. The disadvantage of this method is that the removal rate of tellurium is lower than 80%, and copper and tellurium enter the solution at the same time. Before the recovery of tellurium is completed, an additional process is required to separate the two.

At present, the recovery process of tellurium from copper anode slime still needs to be improved.

Contents of the invention

The present invention aims to solve at least one of the above technical problems.

Aiming at the shortcomings of the existing tellurium recovery process in copper anode slime, the present invention provides a method for selectively recovering tellurium from copper anode slime. The present invention adopts oxygen pressure alkali leaching— _{Na 2} S leaching—SO ₂ reduction process, and selectively Tellurium is removed, copper is enriched in the slag, and tellurium is recovered from solution. The method of the invention can efficiently leach tellurium, reduce tellurium from solution, and enrich copper, silver and gold.

A method for selectively recovering tellurium from copper anode slime, comprising the steps of:

(1) Oxygen pressure alkali leaching deselenium: under certain temperature and oxygen partial pressure conditions, copper anode slime is leached with NaOH solution, and solid-liquid separation is obtained to obtain leaching solution I and leaching slag I;

(2) Na ₂ S leaching to remove tellurium: leaching the leaching residue I with Na ₂ S solution, and separating the solid and liquid to obtain the leaching liquid II and the leaching residue II;

(3) SO ₂ is reduced to obtain crude tellurium: SO ₂ is introduced into the leaching solution II, reacted for a period of time, and solid-liquid separation is obtained to obtain the de-tellurium solution and crude tellurium.

In some embodiments, the concentration of the NaOH solution in step (1) is 1.5-2.5 mol/L, such as 1.5 mol/L, 2.0 mol/L, 2.5 mol/L. Studies have found that within the concentration range of NaOH solution, selenium is better leached; while the leaching rates of tellurium, copper, silver, and gold are far lower than 1%, they are enriched in the leaching residue I; if the concentration of NaOH solution is lower than 1.5 mol/L, the leaching rate of selenium is significantly reduced.

In some embodiments, the time of step (1) oxygen pressure alkaline leaching is 3.5-5.0 hours, such as 3.5 hours, 4 hours, 4.5 hours, 5 hours. The study found that within this time frame, selenium is better leached, and the leaching rate of selenium is between 92% and 99%; the leaching rates of tellurium, copper, silver, and gold are less than 1%, and they are enriched in the leaching residue I ; If the time is lower than 3.5h, the leaching rate of selenium is less than 80%.

In some embodiments, the temperature of step (1) oxygen pressure alkaline leaching is greater than or equal to 200°C. Studies have found that in this temperature range, selenium is better leached, and the leaching rate of selenium can reach 99%; and the leaching rates of tellurium, copper, silver, and gold are less than 1%, and they are enriched in the leaching residue I; If the temperature is lower than 200°C, the leaching rate of selenium is less than 85%.

In some embodiments, the liquid-solid ratio of NaOH solution to copper anode slime in step (1) is greater than or equal to 6:1 mg/L, preferably (6-7):1 mg/L. The study found that within the liquid-solid ratio range, selenium can be leached better, and the leaching rate of selenium can reach 99%; and the leaching rates of tellurium, copper, silver, and gold are lower than 1%, and they are enriched in the leaching residue I; If the liquid-solid ratio is lower than 6:1 mg/L, the leaching rate of selenium is lower than 80%.

In some embodiments, in step (1), the oxygen partial pressure is 0.45-0.9 MPa, such as 0.45 MPa, 0.75 MPa, 0.9 MPa. Studies have found that the leaching rate of selenium in this oxygen partial pressure range can reach more than 99%; and the loss of tellurium, copper, silver, and gold is less than 1%, and they are enriched in the leaching residue I; if the oxygen partial pressure is lower than 0.45MPa , then the leaching rate of selenium will be lower than 60%.

In some embodiments, in step (2), the concentration of the Na ₂ S solution is greater than or equal to 1.0mol/L, optionally 1.0-2.5mol/L, such as 1.0mol/L, 1.5mol/L, 2.0mol/L , 2.5mol/L. Studies have found that within this concentration range, it is beneficial to better leaching tellurium and antimony, and the leaching rates of tellurium and antimony are between 93% and 94%, and 55% and 60%, respectively; while the loss of copper, silver and gold is almost If the concentration is lower than 1.0mol/L, the leaching rates of tellurium and antimony are less than 65% and 30%, respectively.

In some embodiments, in step (2), the Na ₂ S leaching time is greater than or equal to 1.5 hours, optionally 1.5-5 hours, such as 1.5 hours, 3 hours, 5 hours. Studies have found that within this time frame, it is beneficial to better leaching tellurium and antimony, and the leaching rates of tellurium and antimony can reach about 94% and 55%; at the same time, the leaching rates of copper, silver, and gold are lower than 1%. In slag II; if the leaching time is less than 1h, the leaching rate of tellurium is less than 89%, and the leaching rate of antimony is less than 50%.

In some embodiments, in step (2), the Na ₂ S leaching temperature is 80-90°C. Studies have found that this temperature range is conducive to better leaching of tellurium and antimony. The leaching rate of tellurium is expected to exceed 90%, and the leaching rate of antimony can reach 50%. The leaching rate of copper, silver, and gold does not exceed 1%. In the leaching slag II; if the temperature is lower than 80°C, the leaching rate of tellurium is about 90%, and the leaching rate of antimony is lower than 50%.

In some embodiments, in step (2), when Na ₂ S is leached, the liquid-solid ratio of Na ₂ S solution to leaching residue I is greater than or equal to 7:1 mg/L, optional (7-10): 1 mg/L, for example 7:1mg/L, 8:1mg/L, 9:1mg/L, 10:1mg/L. Research has found that within this liquid-solid ratio range, it is beneficial to better leaching tellurium and antimony, and the leaching rate of tellurium is higher than 90%; and it can make the leaching rate of copper, silver, and gold zero, and stay in the leaching residue II; if If the liquid-solid ratio is less than 7:1mg/L, the leaching rates of tellurium and antimony are less than 60% and 40% respectively.

In some embodiments, in step (3), the SO ₂ flow rate is 20-45mL/min, such as 20mL/min, 25mL/min, 30mL/min, 35mL/min, 40mL/min, 45mL/min. It is found that within this flow rate range is beneficial to improve the reduction recovery rate of tellurium and the purity of tellurium in crude tellurium; if the SO ₂ flow rate is lower than 20mL/min, the reduction recovery rate of tellurium is lower than 80%. If the SO ₂ flow rate is higher than 45 mL/min, although the tellurium recovery is higher than 99%, the purity of tellurium is lower than 80%.

In some embodiments, in step (3), the time for introducing SO ₂ is 25-45 min, such as 25 min, 28 min, 30 min, 32 min, 35 min, 40 min, 45 min. Studies have found that within this time range, it is beneficial to improve the reduction recovery rate of tellurium and the purity of tellurium in crude tellurium. The reduction recovery rate of tellurium is expected to reach more than 95%, and the purity reaches 90%. If the time is lower than 25min, the reduction of tellurium The recovery rate was less than 90%.

In some embodiments, in step (3), the temperature of SO ₂ reduction is 40-70°C, such as 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C. The study found that the temperature range is beneficial to improve the reduction recovery rate of tellurium and the purity of tellurium in crude tellurium.

In some embodiments, the specific steps of the method for selectively recovering tellurium from copper anode slime are as follows:

(1) Oxygen pressure alkaline leaching for selenium removal: configure different concentrations of NaOH solutions according to requirements, and put copper anode slime and a certain volume of NaOH solution into the autoclave according to the set liquid-solid ratio. After sealing the autoclave, start stirring and heat up. After the target temperature is reached, oxygen is introduced, the oxygen partial pressure in the kettle rises to the target value, and the timing is started. After the reaction is completed, the solid and liquid are separated to obtain the leaching solution I and the leaching residue I;

(2) Na ₂ S leaching to remove tellurium: Prepare Na ₂ S solutions with different concentrations according to requirements, and put a certain volume of Na ₂ S solution into a polytetrafluoroethylene beaker according to the set liquid-solid ratio, heat the solution to the target temperature, add leaching For slag I, start stirring and timing, and separate solid and liquid after the reaction to obtain leaching liquid II and leaching slag II;

(3) SO ₂ reduction to obtain crude tellurium: Take the leaching solution II and put it into a beaker, heat it to the set temperature and start stirring, pass SO ₂ into the solution at a certain rate, continue to pass for a period of time, stop the ventilation and continue stirring, the solid-liquid The crude tellurium and tellurium-removed liquid are obtained by separation.

In some embodiments, the specific steps of the method for selectively recovering tellurium from copper anode slime are as follows:

(1) Oxygen pressure alkali leaching deselenium: configure 1.5-2.0mol/L NaOH solution, according to the liquid-solid ratio (6-7): 1mg/L, take NaOH solution and copper anode slime into the autoclave, seal the autoclave Start the stirring and raise the temperature, and then introduce oxygen after rising to 200°C, start timing when the oxygen partial pressure in the kettle rises to 0.45-0.75MPa, and separate the solid and liquid after reacting for 5 hours to obtain the leaching solution I and the leaching residue I;

(2) Na ₂ S leaching to remove tellurium: prepare 1.0-1.5mol/L Na ₂ S solution, take the Na ₂ S solution into a polytetrafluoroethylene beaker according to the liquid-solid ratio of 10:1 mg/L, and heat the solution to 80- At 90°C, add leaching residue I, start stirring and timing, react for 3-5 hours and separate solid and liquid to obtain leaching liquid II and leaching residue II;

(3) SO ₂ reduction to obtain crude tellurium: Take 60mL leachate II into a beaker, heat to 40°C and start stirring, feed SO ₂ into the solution at 30-45mL/min for 35-40min, stop aeration and continue Stir for 30 minutes, and separate the solid and liquid to obtain crude tellurium and tellurium-removed liquid.

In some embodiments, the main components of copper anode slime raw materials include (by mass fraction): Cu 15-30%, Se 3-28%, Te 0.5-15%, Pb 0.2-30%, Sb 0.01-30%, Ag 0.1-25%, Au 0.01-5%. But the technical solution of the present invention is not limited to the copper anode slime only used in this material content.

In some embodiments, the main components of copper anode slime raw materials include (by mass fraction): Cu 18.90%, Se 5.72%, Te 1.49%, Pb 11.20%, Sb 2.62%, Ag 7.13%, Au 0.12%.

On the basis of conforming to common knowledge in the field, the above-mentioned preferred conditions can be combined with each other to obtain preferred examples of the present invention.

The invention adopts an oxygen pressure alkali leaching-Na ₂ S leaching-SO ₂ reduction method to treat copper anode slime to realize step-by-step removal of selenium and tellurium, selective recovery of tellurium, and enrichment of valuable metals such as copper and silver.

Compared with the prior art, the present invention has at least one of the following technical effects:

(1) In the oxygen pressure alkaline leaching process, the removal rate of selenium can reach 99%, while tellurium and copper are almost not lost, and they are enriched in the slag. This method achieves the effects of high-efficiency removal of selenium and effective separation of selenium and tellurium in the pyrotechnic process, but avoids the corresponding disadvantages of flue gas pollution and high energy consumption;

(2) In the previous oxygen pressure alkaline leaching-sulfuric acid leaching process, it is impossible to take into account the efficient leaching of tellurium and the effective separation between copper and tellurium. The leaching rate of tellurium is often lower than 85%, and more than 95% of copper enters the solution, so it is impossible to directly obtain tellurium from the solution. In the Na ₂ S leaching process, the leaching rate of tellurium is higher than 94%, and the leaching rate of copper is lower than 1%, which realizes the selective removal of tellurium and the enrichment of copper in the slag.

(3) In the SO ₂ reduction process, the reduction recovery rate of tellurium reaches over 97%, especially the direct one-step reduction to obtain crude tellurium with a purity higher than 90%, realizing the efficient recovery of tellurium, which is higher than the recovery efficiency of tellurium in acidic solutions in the past . In addition, there is no need to introduce chloride ion catalysis into the system, and the composition of the solution after tellurium removal is simple, which is convenient for subsequent treatment.

Description of drawings

Figure 1 is a process flow diagram of an embodiment of the present invention.

Detailed ways

The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

The process flow of the following method for selectively recovering tellurium from copper anode slime is shown in FIG. 1 .

The following are all made of copper anode slime from a domestic copper smelter. The main components of the raw materials are: Cu 18.90%, Se5.72%, Te 1.49%, Pb 11.20%, Sb 2.62%, Ag 7.13%, Au 0.12%.

Example 1

This embodiment provides a method for selectively recovering tellurium from copper anode slime, the steps are as follows:

(1) Oxygen pressure alkali leaching deselenium: configure 1.5mol/L NaOH solution, take 35mL NaOH solution and 5g copper anode slime into the autoclave according to the liquid-solid ratio of 7:1mg/L, seal the autoclave, start stirring and heat up After rising to 200°C, oxygen is introduced, and the oxygen partial pressure in the kettle rises to 0.75MPa to start timing. After 3.5 hours of reaction, solid-liquid separation is obtained to obtain leaching solution I and leaching residue I;

(2) Na ₂ S leaching to remove tellurium: prepare 1.0mol/L Na ₂ S solution, take 35mL Na ₂ S solution into a polytetrafluoroethylene beaker according to the liquid-solid ratio of 7:1 mg/L, heat the solution to 80°C, Add 5g of leaching residue I, start stirring and timing, react for 1.5h and separate solid and liquid to obtain leaching solution II and leaching residue II;

(3) SO ₂ reduction to obtain crude tellurium: take 60mL leachate II into a beaker, heat to 40°C and start stirring, feed SO ₂ into the solution at 20mL/min for 43min, stop ventilation and continue stirring for 30min, solid The liquid is separated to obtain the crude tellurium and the liquid after the tellurium removal.

Analysis and detection: in the step (1), the leaching rate of selenium is about 95%, and tellurium, copper, silver, and gold are hardly leached, and are enriched in the leaching slag I. In step (2), the leaching rate of tellurium is about 91%, the leaching rate of antimony is close to 45%, copper, silver, gold and residual selenium are not leached, and remain in the leaching slag II. The reduction recovery rate of tellurium in step (3) is 94.7%, and the purity of tellurium in the crude tellurium is higher than 90%.

Example 2

This embodiment provides a method for selectively recovering tellurium from copper anode slime, the steps are as follows:

(1) Oxygen pressure alkali leaching deselenium: carry out oxygen pressure alkali leaching according to the method of embodiment 1 step (1), all the other conditions are adjusted to: NaOH concentration 2.0mol/L, reaction time 5h, liquid-solid ratio 7:1mg/L , solid-liquid separation to obtain leachate I and leaching residue I;

(2) Na ₂ S leaching to remove tellurium: perform Na ₂ S leaching according to the method of step (2) of Example 1, and adjust the conditions as follows: Na ₂ S solution concentration 1.5mol/L, temperature 90°C, liquid-solid ratio 10:1mg /L, reaction time 3h, solid-liquid separation to obtain leaching solution II and leaching residue II.

(3) _SO2 reduction to obtain crude tellurium: carry out _SO2 reduction according to the method of step (3) of Example 1, and adjust the remaining conditions as follows: _SO2 flow rate 45mL/min, ventilation time 35min, solid-liquid separation to obtain crude tellurium and tellurium removal after liquid.

Analysis and detection: in step (1), the leaching rate of selenium is close to 99%, and tellurium, copper, silver, and gold are hardly leached, and are enriched in the leaching slag I. In step (2), the leaching rate of tellurium is about 94.3%, the leaching rate of antimony is close to 50%, copper, silver, gold and residual selenium are not leached, and remain in the leaching slag II. The reduction recovery rate of tellurium in the step (3) exceeds 99%, and the purity of tellurium in the crude tellurium is higher than 90%.

Example 3

This embodiment provides a method for selectively recovering tellurium from copper anode slime, the steps are as follows:

(1) Oxygen pressure alkali leaching deselenium: carry out oxygen pressure alkali leaching according to the method of embodiment 1 step (1), all the other conditions are adjusted to: NaOH concentration 2.5mol/L, solid-liquid separation obtains leach solution I and leach residue I;

(2) Na ₂ S leaching to remove tellurium: perform Na ₂ S leaching according to the method of step (2) of Example 1, and adjust the remaining conditions as follows: Na ₂ S solution concentration 2.0mol/L, liquid-solid ratio 10:1mg/L, Solid-liquid separation obtains leachate II and leach residue II.

(3) _SO2 reduction to obtain crude tellurium: carry out _SO2 reduction according to the method of step (3) of Example 1, the conditions are adjusted to: temperature 50°C, _SO2 flow rate 30mL/min, aeration time 45min, solid-liquid separation to obtain crude tellurium And after the tellurium removal.

Analysis and detection: in the step (1), the leaching rate of selenium is 92.5%, and tellurium, copper, silver, and gold are hardly leached, and are enriched in the leaching slag I. In step (2), the leaching rate of tellurium is about 92.9%, the leaching rate of antimony is close to 60%, copper, silver, gold and residual selenium are not leached, and remain in the leaching slag II. The reduction recovery rate of tellurium in the step (3) exceeds 99%, and the purity of tellurium in the crude tellurium is higher than 90%.

Example 4

This embodiment provides a method for selectively recovering tellurium from copper anode slime, the steps are as follows:

(1) Oxygen pressure alkali leaching deselenium: carry out oxygen pressure alkali leaching according to the method of embodiment 1 step (1), all the other conditions are adjusted to: oxygen partial pressure 0.45MPa, liquid-solid ratio 6:1mg/L, reaction time 5h, Solid-liquid separation to obtain leachate I and leach residue I;

(2) Na ₂ S leaching to remove tellurium: Na ₂ S leaching is carried out according to the method of step (2) of Example 1, and the remaining conditions are adjusted to: liquid-solid ratio 10:1 mg/L, reaction time 5 h, solid-liquid separation to obtain leachate II and leach residue II.

(3) _SO2 reduction to obtain crude tellurium: carry out _SO2 reduction according to the method of step (3) of Example 1, and adjust the remaining conditions as follows: _SO2 flow rate 30mL/min, ventilation time 40min, solid-liquid separation to obtain crude tellurium and tellurium removal after liquid.

Analysis and detection: in step (1), the leaching rate of selenium is about 99%, and tellurium, copper, silver, and gold are hardly leached, and are enriched in the leaching slag I. In step (2), the leaching rate of tellurium is about 93.3%, the leaching rate of antimony is close to 60%, copper, silver, gold and residual selenium are not leached, and remain in the leaching slag II. The reduction recovery rate of tellurium in step (3) is 95.6%, and the purity of tellurium in the crude tellurium is higher than 90%.

Example 5

This embodiment provides a method for selectively recovering tellurium from copper anode slime, the steps are as follows:

(1) Oxygen pressure alkali leaching deselenium: carry out oxygen pressure alkali leaching according to the method of embodiment 1 step (1), all the other conditions are adjusted to: oxygen partial pressure 0.9MPa, liquid-solid ratio 6:1mg/L, reaction time 5h, Solid-liquid separation to obtain leachate I and leach residue I;

(2) Na ₂ S leaching to remove tellurium: Na ₂ S leaching is carried out according to the method of step (2) of Example 1, and the other conditions are adjusted to: liquid-solid ratio 10:1 mg/L, temperature 85°C, solid-liquid separation to obtain leachate II and leach residue II.

(3) _SO2 reduction to obtain crude tellurium: carry out _SO2 reduction according to the method of step (3) of Example 1, the conditions are adjusted to: temperature 70°C, _SO2 flow rate 45mL/min, aeration time 32min, solid-liquid separation to obtain crude tellurium And after the tellurium removal.

Analysis and detection: in step (1), the leaching rate of selenium is about 98.7%, and tellurium, copper, silver, and gold are hardly leached, and are enriched in the leaching slag I. The leaching rate of tellurium in step (2) is 94%, the leaching rate of antimony is close to 58%, copper, silver, gold and residual selenium are not leached, and remain in the leaching slag II. The reduction recovery rate of tellurium in step (3) is 96.4%, and the purity of tellurium in the crude tellurium is higher than 90%.

Comparative example 1

This comparative example provides a kind of method that selectively reclaims tellurium from copper anode slime, and the steps are as follows:

(1) Oxygen pressure alkali leaching deselenium: carry out oxygen pressure alkali leaching according to the method of embodiment 1 step (1), all the other conditions are adjusted to: NaOH concentration 1.0mol/L, reaction time 2h, solid-liquid separation obtains leaching solution I and leaching Slag I;

(2) Na ₂ S leaching to remove tellurium: perform Na ₂ S leaching according to the method of step (2) of Example 1, and adjust the remaining conditions to: Na ₂ S concentration of 0.5 mol/L, solid-liquid separation to obtain leach solution II and leach residue II .

(3) _SO2 reduction to obtain crude tellurium: carry out _SO2 reduction according to the method of step (3) of Example 1, and adjust the other conditions as follows: aeration time 20min, solid-liquid separation to obtain crude tellurium and tellurium-removed liquid.

Analysis and detection: in step (1), the selenium leaching rate is about 68%, and tellurium, copper, silver, and gold are hardly leached, and are enriched in the leaching slag I. In step (2), the leaching rate of tellurium was 61.6%, that of antimony was close to 27%, and copper, silver, gold and residual selenium were not leached and remained in leaching slag II. The reduction recovery rate of tellurium in step (3) is 80.2%, and the purity of tellurium in the crude tellurium is higher than 90%.

Comparative example 2

This comparative example provides a kind of method that selectively reclaims tellurium from copper anode slime, and the steps are as follows:

(1) Oxygen pressure alkaline leaching deselenium: carry out oxygen pressure alkaline leaching according to the method of embodiment 1 step (1), and the remaining conditions are adjusted to: temperature 180 ° C, solid-liquid separation to obtain leach solution I and leach residue I;

(2) Na ₂ S leaching to remove tellurium: Na ₂ S leaching is carried out according to the method of step (2) of Example 1, and the remaining conditions are adjusted to: liquid-solid ratio 5:1mg/L, time 1h, solid-liquid separation to obtain leachate II and Leach residue II.

(3) _SO2 reduction to obtain crude tellurium: carry out _SO2 reduction according to the method of Example 1 step (3), the conditions are adjusted to: temperature is room temperature, _SO2 flow rate 10mL/min, solid-liquid separation to obtain crude tellurium and after tellurium removal liquid.

Analysis and detection: in the step (1), the leaching rate of selenium is about 82%, and tellurium, copper, silver, and gold are hardly leached, and are enriched in the leaching slag I. In step (2), the leaching rate of tellurium is 47.3%, that of antimony is close to 14.5%, and copper, silver, gold and residual selenium are not leached, and remain in the leaching slag II. The reduction recovery rate of tellurium in step (3) is 78.4%, and the purity of tellurium in the crude tellurium is higher than 90%.

Although the present invention has been described in detail with general descriptions and specific embodiments above, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. 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 (8)

1. A method for selectively reclaiming tellurium from copper anode slime, is characterized in that, comprises the following steps: (1) Oxygen pressure alkali leaching deselenium: under certain temperature and oxygen partial pressure conditions, copper anode slime is leached with NaOH solution, and solid-liquid separation is obtained to obtain leaching solution I and leaching slag I; The concentration of the NaOH solution is 1.5-2.5mol/L; the time of the oxygen pressure alkali leaching is 3.5-5.0h; the temperature of the oxygen pressure alkali leaching is greater than or equal to 200°C; the NaOH solution and the copper anode slime The liquid-solid ratio is greater than or equal to 6:1mg/L; in the step (1), the oxygen partial pressure is 0.45-0.9Mpa; (2) Na ₂ S leaching to remove tellurium: leaching the leaching residue I with Na ₂ S solution, and separating the solid and liquid to obtain the leaching liquid II and the leaching residue II; The concentration of the Na ₂ S solution is greater than or equal to 1.0mol/L; the Na ₂ S leaching time _is greater than or equal to 1.5h; the Na ₂ S leaching temperature is 80-90°C; the Na ₂ S solution and the leaching The liquid-solid ratio of slag I is greater than or equal to 7:1mg/L; (3) SO ₂ reduction to obtain crude tellurium: pass SO ₂ into the leaching solution II, react for a period of time, and separate the solid and liquid to obtain the de-tellurium solution and crude tellurium; The SO ₂ flow rate is 20-45mL/min; the SO ₂ feeding time is 25-45 min; the SO ₂ reduction temperature is 40-70°C. 2. The method according to claim 1, characterized in that the NaOH solution concentration of step (1) is 1.5mol/L, 2.0mol/L or 2.5mol/L; and/or, The time of step (1) oxygen pressure alkali leaching is 3.5h, 4h, 4.5h or 5h; And/or, The liquid-solid ratio of NaOH solution and copper anode slime in step (1) is (6-7): 1mg/L; And/or, In step (1), the oxygen partial pressure is 0.45MPa, 0.75MPa or 0.9MPa. 3. The method according to claim 1, characterized in that the _Na2S solution concentration in step (2) is 1.0-2.5mol/L; and/or, The time for Na ₂ S leaching in step (2) is 1.5-5h; and/or, Liquid-solid ratio (7-10) of Na ₂ S solution to leaching residue I during Na ₂ S leaching in step (2): 1 mg/L. 4. The method according to claim 1, characterized in that the _Na2S solution concentration in step (2) is 1.0mol/L, 1.5mol/L, 2.0mol/L or 2.5mol/L; and/ or, The time for Na ₂ S leaching in step (2) is 1.5h, 3h or 5h; and/or, During Na ₂ S leaching in step (2), the liquid-solid ratio of Na ₂ S solution to leaching residue I is 7:1 mg/L, 8:1 mg/L or 9:1 mg/L. 5. method according to claim 1, is characterized in that, SO described in step (3) flow rate is 20mL/min, 25mL/min, 30mL/min, 35mL/min, 40mL/min or 45mL _/ min; and / or, In step (3), feed SO The time for _25min , 28min, 30min, 32min, 35min, 40min or 45min; And/or, The temperature of _SO2 reduction in step (3) is 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C. 6. The method according to claim 1, characterized in that, comprising the steps of: (1) Oxygen pressure alkali leaching deselenium: configure 1.5-2.0mol/L NaOH solution, according to the liquid-solid ratio (6-7): 1mg/L, take NaOH solution and copper anode slime into the autoclave, seal the autoclave Start the stirring and raise the temperature, and then introduce oxygen after rising to 200°C, start timing when the oxygen partial pressure in the kettle rises to 0.45-0.75MPa, and separate the solid and liquid after reacting for 5 hours to obtain the leaching solution I and the leaching residue I; (2) Na ₂ S leaching to remove tellurium: prepare 1.0-1.5mol/L Na ₂ S solution, take the Na ₂ S solution into a polytetrafluoroethylene beaker according to the liquid-solid ratio of 10:1 mg/L, and heat the solution to 80- At 90°C, add leaching residue I, start stirring and timing, react for 3-5 hours and separate solid and liquid to obtain leaching liquid II and leaching residue II; (3) SO ₂ reduction to obtain crude tellurium: Take 60mL leachate II into a beaker, heat to 40°C and start stirring, feed SO ₂ into the solution at 30-45mL/min for 35-40min, stop aeration and continue Stir for 30 minutes, and separate the solid and liquid to obtain crude tellurium and tellurium-removed liquid. 7. The method according to any one of claims 1-6, characterized in that the main components of the copper anode slime raw material in terms of mass fraction include: Cu 15-30%, Se 3-28%, Te 0.5-15% %, Pb 0.2-30%, Sb 0.01-30%, Ag 0.1-25%, Au 0.01-5%. 8. The method according to claim 7, wherein the main components of the copper anode slime raw material include: Cu 18.90%, Se 5.72%, Te 1.49%, Pb 11.20%, Sb 2.62%, Ag 7.13%, Au 0.12%.