WO2022237532A1

WO2022237532A1 - Harmless treatment method for recovering sulfur, rhenium, and arsenic from arsenic sulfide slag

Info

Publication number: WO2022237532A1
Application number: PCT/CN2022/089408
Authority: WO
Inventors: 刘智勇; 刘志宏; 洪明浩; 李启厚; 张家润; 何雯睿
Original assignee: 中南大学
Priority date: 2021-05-13
Filing date: 2022-04-26
Publication date: 2022-11-17
Also published as: GB202316454D0; GB2621039A; CN113430385B; CN113430385A

Abstract

The present invention belongs to the technical field of metallurgy, and specifically relates to a harmless treatment method for recovering sulfur, rhenium, and arsenic from arsenic sulfide slag. The method comprises four steps, namely oxygen pressure acid leaching, hot filtration, selective arsenic precipitation, and rhenium adsorption. According to the method, arsenic is preferentially precipitated, and reaction conditions are well controlled in the precipitation process, such that the loss of rhenium in the arsenic precipitation process is very small, and thus arsenic and rhenium are separated; and the resin is improved in the separated solution to improve the adsorption efficiency of rhenium, thereby obtaining high-purity rhenium products. Compared with other methods, the present invention solves the problem of arsenic and the valuable metals copper and rhenium being unable to be completely separated, and efficiently stabilizes arsenic. By means of the method in the present invention, sulfur and rhenium can be recovered from the arsenic sulfide slag, and arsenic can be harmlessly treated, and the method has the advantages of being environmentally friendly, economically viable, energy saving and high efficiency, having a high resource recovery rate, etc.

Description

A method for recovering sulfur rhenium and arsenic harmless disposal from arsenic sulfide slag

technical field

The invention belongs to the technical field of metallurgy, and in particular relates to a method for recovering sulfur rhenium from arsenic sulfide slag and harmless disposal of arsenic.

Background technique

During the process of pyrometallurgy, a large amount of flue gas will be produced. After cooling and washing with dilute acid, the flue gas will be sent to the acid system, and the particles containing arsenic and heavy metals mixed in the flue gas will dissolve in the dilute acid to form "polluted acid". . In order to remove arsenic and heavy metals in sewage acid and minimize the amount of arsenic-containing waste, the sulfidation precipitation method has become one of the commonly used methods in smelters. The yellow solid produced during the precipitation process is "arsenic sulfide slag". Arsenic sulfide slag is a hazardous waste. Generally speaking, arsenic sulfide slag contains valuable metals, such as copper (Cu) and rhenium (Re). The content of Re in the earth's crust is very low, mainly associated with metal sulfide ores, and is an extremely valuable scattered metal. Because of its excellent properties such as high temperature resistance and corrosion resistance, it is widely used in high temperature alloys, aerospace and other important fields, and is an important resource. Therefore, it is of great significance to recover Re from arsenic sulfide slag. Generally speaking, the content of Re in arsenic sulfide slag is between 0.1-2%, which has huge economic recovery value.

Therefore, it is particularly urgent to develop a process for recovering sulfur rhenium from arsenic sulfide slag and for harmless disposal of arsenic.

Contents of the invention

At present, there are two main methods for dealing with arsenic sulfide slag, one is to reduce the leaching toxicity of arsenic sulfide slag through stabilization and solidification, and the other is to convert arsenic sulfide slag into arsenic-containing products in a resourceful way for recycling . The inventors found that the concentration of rhenium in the arsenic-containing solution obtained from the treatment of arsenic sulfide slag is very low, and it is very difficult to recover and prepare high-purity rhenium products from this arsenic-containing solution.

Therefore, the present invention provides a method for recovering sulfur rhenium from arsenic sulfide slag and arsenic harmless disposal. This method makes arsenic preferentially precipitated, and the reaction conditions are well controlled during the precipitation process, so that the loss of rhenium in the process of arsenic precipitation is very small, so that the arsenic and copper rhenium are separated, and the separated solution improves the resin to improve the adsorption efficiency of rhenium. In order to obtain high-purity rhenium products. In addition, the arsenic sulfide slag is leached by oxygen pressure acid, and the arsenic, copper, and rhenium in the slag are leached efficiently. At the same time, part of the trivalent arsenic in the leach solution is partially oxidized to pentavalent arsenic. , will improve the arsenic deposition efficiency and the stability of the arsenic deposition residue in the selective arsenic deposition process. Compared with other methods, the present invention solves the problem that the arsenic and the valuable metal copper-rhenium cannot be completely separated, and realizes the stabilization of the arsenic efficiently. The method of the invention can recover sulfur, copper and rhenium from the arsenic sulfide slag, and can also treat the arsenic harmlessly, and has the advantages of environmental protection, economy, energy saving, high efficiency, high resource recovery rate and the like.

A method for recovering sulfur rhenium and arsenic harmless disposal from arsenic sulfide slag, comprising the following steps:

(1) Oxygen pressure acid leaching: take arsenic sulfide slag in the reaction kettle, add sulfuric acid and additives therein, pass oxidizing gas into the reaction kettle, carry out oxygen pressure leaching, after the oxygen pressure leaching is finished, carry out separation, obtain containing Arsenic-copper-rhenium leaching solution A and sulfur-containing leaching slag A;

(2) Thermal filtration: the obtained sulfur-containing leaching residue A is washed with water, dried, placed in a filter device with good airtightness, then the filter device is heated, and suction filtration is started to obtain sulfur and thermal filter residue B;

(3) Selective precipitation of arsenic: Add the obtained arsenic-containing copper rhenium leaching solution A into the reaction kettle, adjust the pH, add the iron salt solution, and feed the oxidizing gas, control the molar ratio Fe/As=0.5-3.0, and continuously The way of feeding is to add a neutralizing agent to the reaction kettle to adjust the pH value of the reaction system to 0.5-5.0; separate the solution after the reaction is completed, and obtain the solution B after scorodite precipitation and arsenic precipitation;

(4) Adsorption of rhenium: add macroporous weakly basic anion resin to carry out the adsorption of rhenium in the arsenic-precipitated liquid B of step (3), then wash the loaded resin with clear water, then desorb to obtain a rhenium-rich desorption solution, and finally The rhenium-rich desorption solution is evaporated and concentrated and cooled to crystallize to obtain ammonium rhenate product.

The method of the present invention is particularly suitable for treating the following arsenic sulfide slag, which includes the following main components in terms of mass percentage: arsenic: 1%-60%, sulfur: 1-50%, copper: 0.1%-5%, Rhenium: 0.1%-2%.

The inventors found that in the oxygen pressure acid leaching process, the six conditions of oxygen pressure leaching temperature, oxygen pressure leaching pressure, sulfuric acid concentration, volume to mass ratio, oxygen pressure leaching time, and selected oxidizing gas will affect the three conditions in the leach solution. The ratio of valence arsenic concentration to pentavalent arsenic concentration affects the stability of arsenic-fixed minerals.

Preferably, in step (1), the temperature of the oxygen pressure leaching is 140-170°C, such as 140°C, 150°C, 160°C, 170°C.

Preferably, in step (1), the pressure of the oxygen pressure leaching is 0.5-3.0 MPa, such as 0.5 MPa, 1 MPa, 1.5 MPa, 2.0 MPa, 2.5 MPa, 3.0 MPa.

Preferably, in step (1), the concentration of sulfuric acid used is 5-50g/L, such as 5g/L, 10g/L, 20g/L, 30g/L, 50g/L.

Preferably, in step (1), the volume to mass ratio (ml:g) of sulfuric acid and arsenic sulfide slag is (3:1)-(20:1), more preferably (10:1)-(20:1) (ml:g).

Preferably, in step (1), the additive is at least one of calcium lignosulfonate and sodium lignosulfonate. The present inventors found that adding the above-mentioned additives during oxygen pressure acid leaching can remove the wrapping of arsenic, copper, and rhenium by sulfur, thereby increasing the leaching rate of arsenic, copper, and rhenium.

Preferably, in step (1), the mass ratio of the additive to the arsenic sulfide slag is (1:200)-(1:20).

Preferably, in step (1), the oxygen pressure leaching is carried out under stirring, and the stirring speed is 500-800r/min.

Preferably, in step (1), the oxygen pressure leaching time is 5-10h.

Preferably, in step (1), the oxidizing gas is selected from at least one of oxygen, air, and oxygen-enriched air.

In some embodiments, the ratio of trivalent arsenic concentration (g/L) to pentavalent arsenic concentration (g/L) in the arsenic-containing copper rhenium leach solution A described in step (1) is (4:1)-(1 :9), such as 4:1, 3:1, 7:3, 6:4, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1 :8, 1:9.

In some embodiments, preferably, the arsenic-containing copper-rhenium leaching solution A in step (1) contains trivalent arsenic and pentavalent arsenic, wherein the content of pentavalent arsenic accounts for 20-90 wt% of the total arsenic content.

As a preferred technical scheme of the present invention, the operation of step (1) is specifically: get arsenic sulfide slag in the reactor, and add sulfuric acid solution and calcium lignosulfonate, the volume to mass ratio of sulfuric acid solution and arsenic sulfide slag (ml :g) is (10:1)-(20:1), the concentration of sulfuric acid is 10-50g/L, and the mass ratio of calcium lignosulfonate to arsenic sulfide slag is (1:200)-(1:50), Pass oxidizing gas into the reaction kettle, carry out oxygen pressure leaching at temperature 140-170°C, oxygen partial pressure 0.5-3.0MPa, rotation speed 500-800r/min, and control the leaching time to 5-10h. Studies have found that this condition can achieve full leaching of arsenic, copper and rhenium, the leaching rate of arsenic can reach 98%, the leaching rate of copper can reach 95%, and the leaching rate of rhenium can reach 96%. The concentration of trivalent arsenic in the solution (g/L) The ratio to the concentration (g/L) of pentavalent arsenic is between (4:1)-(1:9). The present inventors found that when trivalent arsenic and pentavalent arsenic exist in the solution at the same time, the process of arsenic precipitation is obviously accelerated, and the leaching concentration of arsenic in scorodite precipitation is lower.

In step (2), the sulfur-containing leaching residue A is recovered by hot filtration to obtain sulfur. Sulfur is available for sale. Hot filter residue B can be returned to the batching system.

Preferably, in step (2), the temperature of the hot filtration is 120-250°C, more preferably the hot filtration is carried out at 130-170°C.

Preferably, in step (2), the time for thermal filtration is 10-120 min, more preferably 10-40 min.

Preferably, in step (2), the pressure of suction filtration is 0.3-2.0Mpa.

The present inventors have found that the sulfur-containing leaching slag A washed and dried is heated and suction-filtered in a well-sealed filter device, the sulfur in the slag can be fully recovered, and a high-purity sulfur product can be obtained, with a purity greater than or equal to 97%. %.

In some embodiments, in step (2), the filter device is heated in an oven.

Preferably, in step (3), the iron salt solution is selected from at least one of ferrous sulfate solution, ferric sulfate solution, ferrous chloride solution, ferric chloride solution, ferrous nitrate solution, and ferric nitrate solution.

In step (3), the neutralizing agent is NaOH solution, for example, the concentration is 0.4-0.7mol/L.

Preferably, in step (3), the pH of the reaction process is controlled to be 1.0-5.0, such as 1.0, 1.5, 2.0, 3.0, 4.0, 5.0.

According to an embodiment of the present invention, in step (3), arsenic and copper-rhenium are completely separated, and there is basically no loss of copper-rhenium in the process of arsenic precipitation. The rate is as high as 99%.

The scorodite precipitate obtained in step (3) can be sent to landfill.

In step (4), described macroporous weakly basic anion resin is PM404, any one in WS418, Tulsimer RCX-5143.

Preferably, in step (4), the mass ratio of the resin to the arsenic sulfide slag in step (1) is (1:10)-(1:5).

Preferably, in step (4), the adsorption temperature is 25-50°C.

Preferably, in step (4), the adsorption time is 6-8h.

In step (4), the desorbent used is any one of ammonium thiocyanate, ammonia water, ammonium thiocyanate and ammonia water mixed solution.

In step (4), the ammonia-containing vapor produced during evaporative concentration is cooled by a condenser tube to obtain dilute ammonia water, which can be used to prepare a desorbent.

Unless otherwise specified, the percentages involved in this article are all mass percentages, and the slag after selective arsenic precipitation and separation is investigated by leaching toxicity test by TCLP method.

The method provided by the invention removes the arsenic in the arsenic sulfide slag through oxygen pressure leaching. The leached slag is washed and dried to obtain sulfur by hot filtration. The purity of the sulfur product is as high as 97%. Arsenic depression step: adding iron salt to the leaching solution to precipitate arsenic, adding alkali continuously according to the reaction speed during the reaction process, controlling the reaction process pH=0.5-5.0, generating stable arsenic-fixing minerals, and making the arsenic precipitation process Copper and rhenium are basically not lost. After separation, the precipitate is piled up in the landfill; the liquid after the arsenic precipitation uses a macroporous weakly basic anion exchange resin for the adsorption of rhenium, and then the loaded resin is washed with clean water, and the rhenium-rich desorption liquid is obtained after desorption. Evaporation concentration and cooling crystallization to obtain ammonium rhenate product; after adsorption, liquid electrolysis recovers copper. The method removes arsenic from the arsenic sulfide slag and synthesizes stable arsenic-fixed minerals, and can recover sulfur, copper and rhenium in the arsenic sulfide slag, realizing the separation of arsenic and valuable metals and making them harmless. The invention has a high comprehensive recovery rate of resources and a wide application range of raw materials, and solves the pollution problem in the extraction process of the traditional process, especially the arsenic sulfide slag produced in the copper smelting process. The advantages of the method are more obvious.

Advantage and positive effect of the inventive method:

1) The present invention adopts the method of oxygen pressure acid leaching to remove all the arsenic in the arsenic sulfide slag, the arsenic content of the raw material after the arsenic removal is low, and valuable metals such as copper and rhenium can be comprehensively recovered to reduce the arsenic content in the product;

2) The present invention adopts oxygen pressure acid leaching to oxidize S ^2- in arsenic sulfide slag to S ⁰ , and then recovers sulfur through hot filtration to obtain sulfur, which solves the problem that sulfur in arsenic sulfide slag is difficult to recover ;

3) The present invention adopts the method of selective arsenic precipitation to make As in the leaching solution synthesize scorodite while allowing Cu and Re in the leaching solution to remain in the solution, so that As is completely separated from Cu and Re, and the synthesized scorodite prevents As from migrating , also makes the As in the smelting system have an ideal open circuit, which is a simple process flow, resource-saving, and environmentally friendly method, and the advantage of the selective arsenic precipitation method is that the harmless As and Cu are simultaneously realized. and Re separation, and the prepared scorodite has good stability, is convenient for stockpiling, and has low process cost;

4) The arsenic oxidant in the arsenic precipitation process is one of oxygen, air or oxygen-enriched air, which has a wide range of sources and low consumption, which reduces the cost in the arsenic oxidation process.

Description of drawings

Fig. 1 is a schematic process flow diagram of the method of the embodiment of the present invention.

Fig. 2 is the SEM image of the arsenic-fixed minerals of Example 1 and Comparative Example.

Fig. 3 is the XRD pattern of the arsenic-fixed minerals of Example 1 and Comparative Example.

Detailed ways

The technical solution of the present invention is described in detail below, please refer to FIG. 1 for the process flow of the embodiment.

Example 1

Taking arsenic sulfide slag from a copper smelter as an example, the main components of the raw material are As 25.8%, Cu 0.21%, Re 0.19%, S 34.70%, and the following steps are used for processing:

(1) Oxygen pressure acid leaching: Weigh a certain amount of arsenic sulfide slag in the reactor, add sulfuric acid solution and calcium lignosulfonate; feed oxidizing gas into the reactor; control the volume of sulfuric acid solution and arsenic sulfide slag The mass ratio is 20:1 (ml:g), the stirring speed is 800r/min, the concentration of sulfuric acid solution used is 10g/L, the mass ratio of calcium lignosulfonate to arsenic sulfide residue is 1:200, and the oxygen partial pressure is 2Mpa. The time is 6 hours, the reaction temperature is 150°C, after the leaching is completed, filter and separate to obtain the leaching solution A and the leaching residue A;

After testing: the leaching rate of arsenic is 98.08%, the leaching rate of copper is 96.38%, the leaching rate of rhenium is 96.83%, the sulfur content of the leaching residue is 91.90%, of which the elemental sulfur content is 90.80%, and the concentration of each element in the leach solution is As 12.65g /L, Cu 101.19mg/L, Re 91.98mg/L, at this time the ratio of trivalent arsenic concentration (g/L) to pentavalent arsenic concentration (g/L) in the leaching solution is 7:3.

(2) Thermal filtration: The obtained sulfur-containing leaching residue A after washing with water is placed in a well-sealed filter device, and the filter device is placed in an oven. 0.4Mpa, to obtain sulfur products.

After testing, the sulfur product contains 97.10% sulfur (S) and 0.03% As.

(3) Selective arsenic precipitation: Add sodium hydroxide solution to the leaching solution A of step (1), adjust pH=2, then add 100mL ferrous sulfate solution, the molar ratio Fe/As is controlled at 2, add NaOH solution simultaneously as Neutralizer, adjust the pH value of the reaction at 2, and finally generate highly stable arsenic-fixing minerals (sororite precipitation). The concentration of the NaOH solution used is 0.4mol/L, and the pumping speed of the NaOH solution is 1ml/min. The time is 3 hours, the reaction temperature is 150°C, and the oxygen pressure is 0.5Mpa.

According to TCLP analysis, the leaching concentration of arsenic in the synthesized arsenic-fixing mineral (sororite) is 0.1114mg/L, which complies with the provisions of GB5085.3-2007 (Solid Waste Identification Standard-Leach Toxicity Identification) and can be safely stockpiled. In the process of selective arsenic precipitation, copper rhenium basically does not precipitate, and the arsenic precipitation rate is as high as 99%.

The SEM image of the arsenic-fixed mineral prepared in this example is shown in a in FIG. 2 , and the XRD image is shown in a in FIG. 3 .

The concentration of each element in the solution after arsenic precipitation is As 20.92mg/L, Cu 41.09mg/L, Re 37.54mg/L.

(4) Adsorption of rhenium: add macroporous weakly basic anion exchange resin PM404 to the liquid B after precipitation of arsenic in step (3) for adsorption of rhenium, the mass ratio of resin to arsenic sulfide slag is 1:10, and shake at 200rpm/min , the time is 6h, the adsorption temperature is 25°C, and then 6mol/L ammonium thiocyanate is used as the desorbing agent, the shaking rate is 150r/min, the desorption temperature is 25°C, and the desorption time is 6h to obtain a rhenium-rich desorption solution. The stripped liquid is evaporated and concentrated, cooled and crystallized to obtain the ammonium rhenate product.

After testing, solution C after adsorption contained 20.78mg/L As, 40.11mg/L Cu, and 0.05mg/L Re, and the desorption solution contained 178.34mg/L Re. Solution C can recover copper by electrolysis after adsorption.

Example 2

Taking arsenic sulfide slag from a copper smelter as an example, the main components of the raw material are As 32.8%, Cu 3.38%, Re 0.26%, S 43.23%, and the following steps are used for processing:

(1) Oxygen pressure acid leaching: Weigh a certain amount of arsenic sulfide slag in the reactor, add sulfuric acid solution and calcium lignosulfonate; feed oxidizing gas into the reactor; control the volume-to-mass ratio of sulfuric acid and arsenic sulfide slag 20:1 (ml:g), stirring speed 800r/min, sulfuric acid solution concentration 20g/L, mass ratio of calcium lignosulfonate to arsenic sulfide slag 1:100, reaction temperature 140°C, oxygen partial pressure 1.5 Mpa, leaching time 7h, after leaching, filter and separate to obtain leaching solution A and leaching residue A;

After testing: the leaching rate of arsenic is 98.23%, the leaching rate of copper is 95.65%, the leaching rate of rhenium is 97.34%, the sulfur content of the leaching residue is 92.30%, of which the elemental sulfur content is 91.23%, and the concentration of each element in the leach solution is As 16.10g /L, Cu 1.61g/L, Re 126.65mg/L, at this time the ratio of trivalent arsenic concentration (g/L) to pentavalent arsenic concentration (g/L) in the leaching solution is 3:1.

(2) Thermal filtration: Place the obtained sulfur-containing leaching residue A after washing in a well-sealed filter device, place the filter device in an oven, set the thermal filtration temperature at 170°C, the reaction time for 15 minutes, and the filtration pressure 0.5Mpa, to obtain sulfur products.

After testing, the sulfur product contains 97.01% sulfur (S) and 0.02% As.

(3) Selective arsenic precipitation: Add sodium hydroxide solution to the leaching solution A of step (1), adjust pH=1.5, then add 100mL ferrous sulfate solution, the molar ratio Fe/As is controlled at 1.5, add NaOH solution simultaneously as Neutralizer, adjust the pH value of the reaction at 1.5, and finally generate highly stable arsenic-fixing minerals (sororite precipitation), the NaOH concentration is 0.7mol/L, the NaOH solution pumping speed is 1ml/min, and the arsenic precipitation time is 2h , the reaction temperature is 150°C, and the oxygen pressure is 0.4Mpa.

According to TCLP analysis, the leaching concentration of arsenic in the synthesized arsenic-fixing mineral scorodite is 0.6684mg/L, which complies with the provisions of GB5085.3-2007 (Solid Waste Identification Standard-Leach Toxicity Identification), and can be safely stockpiled. In the process of selective arsenic precipitation, copper rhenium basically does not precipitate, and the arsenic precipitation rate is as high as 99%. The concentration of each element in the solution after arsenic precipitation is As 33.44mg/L, Cu 0.73g/L, Re 59.30mg/L.

(4) Adsorption of rhenium: add macroporous weakly basic anion exchange resin WS418 to the liquid B after the arsenic precipitation in step (3) to carry out the adsorption of rhenium, the mass ratio of resin to arsenic sulfide slag is 1:10, at 200rpm/min Oscillation, the time is 7h, the adsorption temperature is 25°C, and then 6mol/L ammonia water is used as the desorption agent, the oscillation rate is 150r/min, the desorption temperature is 25°C, and the desorption time is 7h to obtain a rhenium-rich desorption solution, and the desorption solution is carried out Concentrate by evaporation and crystallize by cooling to obtain ammonium rhenate product.

After testing, the solution C after adsorption contained As 32.32mg/L, Cu 0.71g/L, and Re 0.07mg/L, and the desorption solution contained Re 245.67mg/L. Solution C can recover copper by electrolysis after adsorption.

Example 3

Taking arsenic sulfide slag from a copper smelter as an example, the main components of the raw material are As 30.90%, Cu 4.10%, Re 0.12%, S 44.78%, and the following steps are used for processing:

(1) Oxygen pressure acid leaching: Weigh a certain amount of arsenic sulfide slag in the reactor, add sulfuric acid solution and calcium lignosulfonate; feed oxidizing gas into the reactor; control the volume-to-mass ratio of sulfuric acid and arsenic sulfide slag 10:1 (ml:g), stirring speed 800r/min, sulfuric acid concentration 50g/L, mass ratio of calcium lignosulfonate to arsenic sulfide slag 1:50, reaction temperature 170°C, oxygen partial pressure 1.0Mpa , the leaching time is 5h, after the leaching is finished, filter and separate to obtain the leaching solution A and the leaching residue A;

After testing: the leaching rate of arsenic is 80.23%, the leaching rate of copper is 77.34%, the leaching rate of rhenium is 79.10%, the sulfur content of the leaching residue is 87.12%, of which the elemental sulfur content is 85.89%, and the concentration of each element in the leach solution is As 24.79g /L, Cu 3.17g/L, Re 94.92mg/L, at this time the ratio of trivalent arsenic concentration (g/L) to pentavalent arsenic concentration (g/L) in the leaching solution is 6:4.

(2) Thermal filtration: Place the obtained sulfur-containing leaching residue A after washing in a well-sealed filter device, place the filter device in an oven, set the thermal filtration temperature at 130°C, the reaction time for 40 minutes, and the filtration pressure 0.7Mpa, to obtain sulfur products.

After testing, the sulfur product contains 97.12% sulfur (S) and 0.05% As.

(3) Selective arsenic precipitation: Add sodium hydroxide solid to the leaching solution A of step (1), adjust pH=1, then add 100mL ferrous sulfate solution, the molar ratio Fe/As is controlled at 3, add NaOH solution simultaneously as Neutralizer, adjust the pH value of the reaction at 1, and finally generate highly stable arsenic-fixing minerals (sororite precipitation), the concentration of NaOH is 0.4mol/L, the pumping speed of NaOH solution is 1ml/min, and the arsenic precipitation time is 3h , the reaction temperature is 150°C, and the air pressure is 1Mpa.

According to TCLP analysis, the synthesized arsenic-fixed minerals meet the requirements of GB5085.3-2007 that the leaching concentration of arsenic in scorodite is 0.0758mg/L (identification standard for solid waste - identification of leaching toxicity), and can be safely stockpiled. During the process, copper rhenium basically does not precipitate, and the arsenic deposition rate is as high as 99%. The concentration of each element in the solution after arsenic precipitation is As 32.34mg/L, Cu 0.82g/L, Re 24.57mg/L.

(4) Adsorption of rhenium: add macroporous weakly basic anion exchange resin Tulsimer RCX-5143 to the liquid B after the arsenic precipitation of step (3) and carry out the adsorption of rhenium, the mass ratio of resin and arsenic sulfide slag is 1:5, with Shaking at 200r/min for 6h, adsorption temperature at 25°C, and then using 6mol/L ammonium thiocyanate as a desorbing agent, shaking rate at 120r/min, desorption temperature at 30°C, and desorption time for 7h to obtain rhenium-rich The desorption liquid is evaporated and concentrated, cooled and crystallized to obtain the ammonium rhenate product.

After testing, the solution C after adsorption contained As 31.80mg/L, Cu 0.82g/L, and Re 0.02mg/L, and the desorption solution contained Re 93.36mg/L. Solution C can recover copper by electrolysis after adsorption.

Example 4

Taking arsenic sulfide slag from a copper smelter as an example, the main components of the raw material are As 21.35%, Cu 5.16%, Re 0.35%, S 46.86%, and the following steps are used for processing:

(1) Oxygen pressure acid leaching: Weigh a certain amount of arsenic sulfide slag in the reactor, add sulfuric acid solution and calcium lignosulfonate; feed oxidizing gas into the reactor; control the volume-to-mass ratio of sulfuric acid and arsenic sulfide slag 10:1 (ml:g), stirring speed 800r/min, sulfuric acid concentration 50g/L, mass ratio of calcium lignosulfonate to arsenic sulfide slag 1:100, reaction temperature 170°C, oxygen partial pressure 3.0Mpa , the leaching time is 10h, and after the leaching is completed, filter and separate to obtain the leaching solution A and the leaching residue A;

After testing: the leaching rate of arsenic is 99.28%, the leaching rate of copper is 98.67%, the leaching rate of rhenium is 99.10%, the sulfur content of the leaching residue is 94.23%, of which the elemental sulfur content is 92.25%, and the concentration of each element in the leach solution is As 21.19g /L, Cu 5.09g/L, Re 346.85mg/L, at this time the ratio of trivalent arsenic concentration (g/L) to pentavalent arsenic concentration (g/L) in the leaching solution is 1:9.

(2) Thermal filtration: Place the obtained sulfur-containing leaching residue A after washing in a well-sealed filter device, place the filter device in an oven, set the thermal filtration temperature at 150°C, the reaction time for 20 minutes, and the filtration pressure 0.7Mpa, to obtain sulfur products.

After testing, the sulfur product contains 98.09% sulfur (S) and 0.01% As.

(3) Selective arsenic precipitation: add sodium hydroxide solid in the leaching liquid A of step (1), adjust pH=1, then add 100mL ferrous sulfate solution, molar ratio Fe/As is controlled at 1.5, adds NaOH solution simultaneously as Neutralizer, adjust the pH value of the reaction at 1.5, and finally generate highly stable arsenic-fixing minerals (sororite precipitation), the NaOH concentration is 0.3mol/L, the NaOH solution pumping speed is 1ml/min, and the arsenic precipitation time is 3h , the reaction temperature is 150°C, and the oxygen pressure is 1Mpa.

According to TCLP analysis, the synthesized arsenic-fixed mineral meets the requirements of GB5085.3-2007 that the leaching concentration of arsenic in scorodite is 0.1427mg/L (identification standard for solid waste - identification of leaching toxicity), and can be safely stockpiled. During the process, copper rhenium basically does not precipitate, and the arsenic deposition rate is as high as 99%. The concentration of each element in the solution after arsenic precipitation is As 28.13mg/L, Cu 1.34g/L, Re 91.02mg/L.

(4) Adsorption of rhenium: add macroporous weakly basic anion exchange resin Tulsimer RCX-5143 to the liquid B after the arsenic precipitation of step (3) and carry out the adsorption of rhenium, the mass ratio of resin and arsenic sulfide slag is 1:5, with Shake at 200r/min for 6 hours, and the adsorption temperature is 30°C, then use 6mol/L ammonium thiocyanate as the desorbing agent, the shaking rate is 150r/min, the desorption temperature is 25°C, and the desorption time is 6h to obtain rhenium-rich The desorption liquid is evaporated and concentrated, cooled and crystallized to obtain the ammonium rhenate product.

After testing, the solution after adsorption contained As 27.55mg/L, Cu 1.33g/L, and Re 0.03mg/L, and the desorption solution contained Re 340.75mg/L. Solution C can recover copper by electrolysis after adsorption.

comparative example

Take the same arsenic sulfide slag as in Example 1, and obtain leach solution A in the same way as in Example 1 step (1). Add the leaching solution A into the reactor, and then pass through SO ₂ gas to reduce the leaching solution to obtain a leaching solution containing only trivalent arsenic, and then heat to remove the SO ₂ dissolved in the solution to obtain a leaching solution A1. The leaching solution A1 was subjected to arsenic precipitation in the same manner as in step (3) of Example 1 to obtain a precipitate.

After TCLP analysis, the leaching concentration of arsenic in the obtained precipitate was 75.326mg/L, which did not meet the requirements of GB5085.3-2007 (identification standard for solid waste - identification of leaching toxicity), and the arsenic deposition rate under this condition was only 55.78%.

This shows that the ratio of trivalent arsenic concentration to pentavalent arsenic concentration in the leaching solution before arsenic precipitation is very important for improving the stability of arsenic-fixed minerals. When the leaching solution only contains trivalent arsenic, stable arsenic-fixed minerals cannot be obtained.

The SEM image of the arsenic-fixed mineral prepared in this comparative example is shown in b in FIG. 2 , and the XRD image is shown in b in FIG. 3 .

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

A method for recovering sulfur rhenium and arsenic harmless disposal from arsenic sulfide slag, characterized in that it comprises the following steps:

(1) Oxygen pressure acid leaching: take arsenic sulfide slag in the reaction kettle, add sulfuric acid and additives therein, pass oxidizing gas into the reaction kettle, carry out oxygen pressure leaching, after the oxygen pressure leaching is finished, carry out separation, obtain containing Arsenic-copper-rhenium leaching solution A and sulfur-containing leaching slag A;

(2) Thermal filtration: the obtained sulfur-containing leaching residue A is washed with water, dried, placed in a filter device with good airtightness, then the filter device is heated, and suction filtration is started to obtain sulfur and thermal filter residue B;

(3) Selective precipitation of arsenic: Add the obtained arsenic-containing copper rhenium leaching solution A into the reaction kettle, adjust the pH, add the iron salt solution, and feed the oxidizing gas, control the molar ratio Fe/As=0.5-3.0, and continuously The way of feeding is to add a neutralizing agent to the reaction kettle to adjust the pH value of the reaction system to 0.5-5.0; separate the solution after the reaction is completed, and obtain the solution B after scorodite precipitation and arsenic precipitation;

(4) Adsorption of rhenium: add macroporous weakly basic anion resin to carry out the adsorption of rhenium in the arsenic-precipitated liquid B of step (3), then wash the loaded resin with clear water, then desorb to obtain a rhenium-rich desorption solution, and finally The rhenium-rich desorption solution is evaporated and concentrated and cooled to crystallize to obtain ammonium rhenate product.
The method according to claim 1, characterized in that, in step (1), the mass ratio of the mass of the additive to the arsenic sulfide slag is (1:200)-(1:20); and/or,

In step (1), the oxygen pressure leaching is carried out under stirring, and the stirring speed is 500-800r/min; and/or,

In step (1), the oxygen pressure leaching time is 1-10h; and/or,

In step (1), the oxidizing gas is at least one selected from oxygen, air, and oxygen-enriched air.
The method according to claim 1 or 2, wherein the ratio of trivalent arsenic concentration (g/L) to pentavalent arsenic concentration (g/L) in the arsenic-containing copper rhenium leach solution A described in step (1) is (4:1)-(1:9), such as 4:1, 3:1, 7:3, 6:4, 1:1, 1:2, 1:3, 1:4, 1:5, 1 :6, 1:7, 1:8, 1:9, or,

In the step (1), the arsenic-containing copper rhenium leach solution A contains trivalent arsenic and pentavalent arsenic, wherein the content of pentavalent arsenic accounts for 20-90wt% of the total arsenic content.
According to the method described in any one of claims 1-3, it is characterized in that the operation of step (1) is specifically: take arsenic sulfide slag in the reactor, and add sulfuric acid solution and calcium lignosulfonate, sulfuric acid solution and The volume-to-mass ratio (ml:g) of arsenic sulfide slag is (3:1)-(20:1), the sulfuric acid concentration is 10-50g/L, and the mass ratio of calcium lignosulfonate to arsenic sulfide slag is (1: 200)-(1:20), feed the oxidizing gas into the reaction kettle, carry out oxygen pressure leaching at a temperature of 140-170°C, an oxygen partial pressure of 0.5-3.0MPa, and a rotation speed of 500-800r/min. The leaching time is controlled to 1-10h.
The method according to any one of claims 1-4, characterized in that, in step (2), the sulfur-containing leaching residue A is reclaimed by hot filtration to obtain sulfur; and/or,

In step (2), the temperature of the thermal filtration is 120-250°C, preferably the thermal filtration is performed at 130-170°C; and/or,

In step (2), the time for thermal filtration is 10-120min, preferably 10-40min; and/or,

In step (2), the pressure of suction filtration is 0.3-2.0Mpa; and/or,

Step (2) Place the filter device in an oven to heat.
The method according to any one of claims 1-5, characterized in that, in step (3), the iron salt solution is selected from ferrous sulfate solution, ferric sulfate solution, ferrous chloride solution, ferric chloride solution , at least one of ferrous nitrate solution, ferric nitrate solution; and/or,

In step (3), the neutralizing agent is NaOH solution with a concentration of 0.4-0.7mol/L; and/or,

In step (3), control the reaction process pH=0.5-5.0, such as 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0; and/or,

In step (3), the reaction temperature is 130-200°C, the reaction time is 2-10h, and the gas pressure is 0.2-3.0Mpa.
according to the method described in any one of claim 1-6, it is characterized in that, in step (4), described macroporous weakly basic anion resin is PM404, any one in WS418, Tulsimer RCX-5143; With /or,

In step (4), the mass ratio of resin to step (1) arsenic sulfide slag is (1:20)-(1:5); and/or,

In step (4), the adsorption temperature is 25-85°C, preferably 25-50°C; and/or,

In step (4), the adsorption time is 5-8h; and/or,

In step (4), the desorbent used is any one of ammonium thiocyanate, ammonia water, ammonium thiocyanate and ammonia water mixed solution.
The method according to any one of claims 1-7, characterized in that, in terms of mass percentage, the arsenic sulfide slag comprises the following main components: arsenic: 1%-60%, sulfur: 1-50%, copper: 0.1%-5%, rhenium: 0.1%-2%.