Method for preparing iron-arsenic alloy from ash containing arsenic and antimony and recovering other valuable elements

Abstract

The invention discloses a method for preparing iron-arsenic alloy from arsenic-antimony-containing soot and recovering other valuable elements, and belongs to the technical field of arsenic-containing solid waste resource utilization. The method comprises the steps that raw materials including the arsenic-antimony-containing soot, a sodium-containing alkaline substance, iron slag and a carbonaceous reducing agent are evenly mixed and then briquetted, obtained pellets are subjected to reduction smelting, after smelting is finished, melt is subjected to standing layering, and a zinc-containing smelting slag layer, an antimony-sodium alloy layer, an iron-arsenic alloy layer and bottom layer crude lead are sequentially arranged from top to bottom. According to the method, the enrichment process of arsenic, antimony and other metals in the arsenic-antimony-containing soot is not needed by adopting a wet process, oriented conversion and separation of arsenic, antimony, lead and zinc in the arsenic-antimony-containing soot can be achieved only through one-step pyrogenic process smelting, products are recycled in the form of iron-arsenic alloy, antimony-sodium alloy, coarse lead alloy zinc-rich slag and the like, the technological process is simple, operation is easy, and the method is suitable for industrial production. And efficient resource utilization of valuable metals in the arsenic-containing soot can be achieved, and industrial production is facilitated.

Description

Technical Field

[0001] This invention relates to a method for treating arsenic-antimony flue dust, and more particularly to a method for preparing iron-arsenic alloys from arsenic-antimony flue dust and recovering other valuable elements, belonging to the field of resource utilization technology for arsenic-containing solid waste. Background Technology

[0002] In the smelting of non-ferrous metals such as copper, lead, and zinc, large amounts of arsenic enter the smelting system along with the concentrate and are released into the flue gas as arsenic oxide. The resulting smelting dust, after dust collection, typically possesses high environmental toxicity. Since oxides of valuable elements such as antimony, lead, and zinc also have high vapor pressures, arsenic-containing dust often also contains significant amounts of these elements. Therefore, developing a rational resource utilization process to convert arsenic into stable arsenic-containing materials, while simultaneously recovering antimony, lead, and zinc, is of great significance.

[0003] Currently, the resource utilization of arsenic- and antimony-containing flue dust mainly employs hydrometallurgical processes. For example, sulfuric acid and sodium hydroxide leaching systems are two commonly used hydrometallurgical leaching systems. Arsenic first enters the leaching solution and is then converted into arsenic sulfide slag and sodium arsenate slag through sulfidation precipitation or freeze crystallization, respectively. Both are highly environmentally harmful and require further solidification treatment, increasing processing costs. The resulting products are also difficult to utilize on a large scale. Furthermore, separating valuable metals such as antimony, lead, and zinc from the flue dust is difficult and inefficient, leading to a long process flow and high reagent consumption in hydrometallurgical treatment of arsenic-containing flue dust. Shortening the arsenic-containing flue dust treatment process, reducing reagent consumption, and simultaneously increasing the added value of the processed products to achieve efficient and clean separation of arsenic, antimony, lead, and zinc are the bottlenecks that urgently need to be overcome in the current technology for the resource utilization of arsenic- and antimony-containing flue dust.

[0004] Chinese patent applications (CN119220804A, CN118745517A) disclose the preparation of environmentally friendly iron-arsenic alloys by co-reducing and smelting arsenic slag and iron slag. However, this method is ineffective in treating arsenic-antimony flue dust, primarily because arsenic, antimony, and lead in the flue dust exist mainly as oxides such as As2O3 and Sb2O. 3、 Primarily composed of PbO, the oxides such as As2O3, Sb2O3, and PbO have higher saturated vapor pressures compared to salts like Na3AsO4 and Na3SbO4 in arsenic-alkali slag. During the smelting process, most of As2O3, Sb2O3, and PbO will volatilize into the flue gas before the actual reaction. Therefore, when using existing methods disclosed in CN119220804A and CN118745517A, the separation effect of solid arsenic and antimony during smelting is extremely poor. Summary of the Invention

[0005] To address the technical problems existing in the prior art, the purpose of this invention is to provide a method for preparing iron-arsenic alloys and recovering other valuable elements from arsenic-antimony flue dust. This method does not require the use of wet processes to enrich metals such as arsenic and antimony in the arsenic-antimony flue dust or to convert them into oxyacids such as Na3AsO4 and Na3SbO4. Instead, it only requires a one-step pyrometallurgical process to achieve the directional conversion of arsenic, antimony, lead, and zinc in the arsenic-antimony flue dust. For example, arsenic is converted into an iron-arsenic alloy, antimony oxide is converted into an antimony-sodium alloy, lead oxide is converted into a crude lead alloy, and zinc remains in its oxidation state. Moreover, the alloy in the melt naturally separates into layers, and zinc oxide is retained in the slag phase, which is easy to separate and recover. This method has a simple process flow, is easy to operate, and can achieve efficient resource utilization of valuable metals in arsenic-containing flue dust, which is beneficial to industrial production.

[0006] To achieve the above-mentioned technical objectives, the present invention provides a method for preparing iron-arsenic alloy and recovering valuable metals by one-step smelting of arsenic-antimony flue dust. The method involves mixing raw materials, including arsenic-antimony flue dust, sodium-containing alkaline substances, iron slag, and carbonaceous reducing agents, and then pressing the mixture into pellets. The resulting pellets are then subjected to reduction smelting. After smelting is completed, the melt is allowed to stand and separate into layers, from top to bottom, to obtain a zinc-containing smelting slag layer, an antimony-sodium alloy layer, an iron-arsenic alloy layer, and a bottom layer of crude lead.

[0007] Based on the mineral composition characteristics of arsenic-antimony flue dust, the valuable metals such as arsenic, antimony, lead, and zinc exist in the form of metal oxides, such as As₂O₃ and Sb₂O. 3、 PbO, ZnO2, etc., due to the high saturated vapor pressure of metal oxides such as As2O3, Sb2O3, and PbO, easily volatilize into the flue gas during the smelting process. The key to this invention lies in the introduction of a sodium-containing alkaline substance. This sodium-containing alkaline substance can decompose into active sodium oxide at high temperatures. Sodium oxide can capture metal oxides such as As2O3, Sb2O3, and PbO to form metal oxyacid salts with better stability, thereby avoiding the high-temperature volatilization of these metal oxides. In the presence of a reducing agent and at the smelting temperature, these metal oxyacid salts are directionally reduced to metals and directionally alloyed. Among them, arsenic is transformed into an iron-arsenic alloy, antimony oxide is transformed into an antimony-sodium alloy, lead oxide is transformed into a crude lead alloy, and zinc remains unchanged in its oxidation state and is enriched in the surface slag. After smelting, these metal phases naturally separate under the action of gravity, thereby achieving clean and efficient separation of valuable metals such as arsenic, antimony, lead, and zinc from arsenic-antimony flue gas.

[0008] As a preferred embodiment, the mass of the sodium-containing alkaline substance is not less than 20% of the mass of the arsenic-antimony-containing flue dust. If the amount of sodium-containing alkaline substance added is too low, it is difficult to fully convert metal oxides such as As2O3, Sb2O3, and PbO into metal oxyacid salts, thereby greatly increasing the volatilization of these metal oxides. On the other hand, if the amount of metal oxyacid salts is too high, it has no significant impact on the process, but mainly increases the smelting cost. Therefore, as a further preferred embodiment, the mass of the sodium-containing alkaline substance is 20-40% of the mass of the arsenic-antimony-containing flue dust.

[0009] As a preferred embodiment, the mass of the iron slag is measured such that the mass of iron in the iron slag is 2.5 to 7 times the mass of arsenic in the arsenic-antimony flue dust. The iron slag is primarily introduced as an iron source, while during the reduction smelting process, the iron is mainly used to capture arsenic to form an iron-arsenic alloy. If the amount of iron slag introduced is too low, some arsenic will fail to alloy and will easily volatilize and be lost. If the amount of iron slag introduced is too high, the iron content in the alloy will increase, not only raising the alloy's melting point, which is detrimental to subsequent smelting processes, but also increasing the melt viscosity, making product stratification difficult.

[0010] As a preferred embodiment, the mass of the carbonaceous reducing agent is 30-80% of the mass of the arsenic-antimony flue dust. Insufficient carbonaceous reducing agent will lead to incomplete reduction of the intermediate metal oxyacid salts, resulting in some metals not being effectively separated and entering the slag phase. Excessive carbonaceous reducing agent not only significantly increases smelting costs but also leads to excessive ash content in the melt, ultimately increasing melt viscosity and making product stratification difficult.

[0011] As a preferred embodiment, the sodium-containing alkaline substance includes at least one of sodium carbonate, sodium hydroxide, and alkaline smelting slag from non-ferrous metallurgy. The sodium-containing alkaline substance is mainly sodium oxide or a substance that can be converted into sodium oxide at high temperatures; common examples include sodium carbonate and sodium hydroxide.

[0012] As a preferred embodiment, the iron slag includes at least one of goethite slag, hematite slag, iron ore, scrap iron, and red mud beneficiation. The iron slag is primarily introduced as an iron source, and common iron-bearing slags and iron minerals all meet the application requirements of this invention.

[0013] As a preferred embodiment, the carbon reducing agent includes at least one of pulverized coal, coke, waste graphite, petroleum coke, charcoal, natural gas, heavy oil, and waste cooking oil. The carbon reducing agent primarily functions as a reducing agent, causing As₂O₃ and Sb₂O₃ to react. 3、 Metal oxides such as PbO are converted into elemental metals.

[0014] As a preferred embodiment, the compressive strength of the pellets is not less than 50 N / pellet. When the compressive strength of the pellets is too low, they are easily crushed during the smelting process, resulting in a large amount of secondary flue dust, with some metal entering the secondary flue dust and reducing the metal recovery rate.

[0015] As a preferred embodiment, the reduction smelting adopts a nitrogen bottom-blowing enhanced reduction smelting method.

[0016] As a preferred embodiment, the reduction smelting conditions are: temperature of 1000~1400 °C and time of 1~3 h. The iron-arsenic alloy prepared by this invention is smelted at approximately 1000 °C. If the smelting temperature is lower than that of the iron-arsenic alloy, the iron-arsenic alloy will not be able to transform into a liquid state, and the alloy phase and slag phase will not be able to separate, leading to furnace failure. If the temperature is too high, the volatilization of arsenic will be accelerated. Extensive experiments have shown that when the temperature is 1000 °C, the maximum arsenic content in the iron-arsenic alloy after smelting can reach 40%. Increasing the temperature to 1100 °C reduces the maximum arsenic content to 35%, and further increasing the temperature to 1400 °C reduces the maximum arsenic content in the alloy to 28%. In addition, increasing the temperature will also increase energy consumption. Therefore, a further preferred smelting temperature is 1000~1300 °C, a more preferred smelting temperature is 1000~1200 °C, and the most preferred smelting temperature is 1000~1100 °C.

[0017] As a preferred embodiment, the nitrogen bottom-blowing flow rate during the reduction smelting process is 0.1~0.5 m³ / ton of furnace charge. 3 / s. Nitrogen bottom blowing can enhance the separation of antimony. Numerous experiments have shown that without nitrogen bottom blowing, the antimony content in smelted iron-arsenic alloys is generally between 4% and 8%. With nitrogen bottom blowing, the antimony content in iron-arsenic alloys can be reduced to as low as 0.5% to 2%, significantly improving the antimony recovery rate. This is mainly because nitrogen bottom blowing can enhance the mixing of the iron-arsenic alloy phase and the sodium carbonate slag phase, thereby enhancing the mass transfer effect of metallic antimony in the iron-arsenic alloy. This promotes the reaction of antimony, slag, and reducing agent to form antimony-sodium alloy, ultimately improving the separation efficiency of antimony from the iron-arsenic alloy.

[0018] As a preferred embodiment, the time for the melt to stand and separate into layers is 30 to 60 minutes.

[0019] Compared with existing technologies, the beneficial technical effects of the present invention are as follows:

[0020] 1) This invention can separate metals such as arsenic, antimony, lead, and zinc from arsenic-containing flue dust in a single pyrometallurgical step, and obtain products such as iron-arsenic alloy, antimony-sodium alloy, crude lead, and high-zinc slag. It truly realizes the efficient resource utilization of arsenic-antimony flue dust and avoids the technical defects of existing technologies that require hydrometallurgical extraction of metals such as arsenic and antimony.

[0021] 2) The iron-arsenic alloy obtained by this invention has a density higher than 7 g / cm³. 3 It has strong environmental stability and can be used as an industrial counterweight material.

[0022] 3) The present invention has significant advantages in the treatment process of arsenic-antimony flue dust, such as being green, having a short process, and being highly adaptable to raw materials. It can realize the efficient resource utilization of arsenic-antimony flue dust, which has significant social and economic benefits and broad application prospects. Attached Figure Description

[0023] Figure 1 This is a flowchart of the invention process.

[0024] Figure 2 The image shows the XRD pattern of the antimony-sodium alloy obtained in Example 1 of this invention.

[0025] Figure 3 The image shows the XRD pattern of the iron-arsenic alloy obtained in Example 1 of this invention.

[0026] Figure 4 Optical images of the smelting slag and antimony-sodium alloy obtained in Example 1 of this invention.

[0027] Figure 5 This is an optical image of the iron-arsenic alloy obtained in Example 1 of the present invention. Detailed Implementation

[0028] The following specific embodiments are intended to further illustrate the content of the present invention, rather than to limit the scope of protection of the claims of the present invention.

[0029] Example 1

[0030] Step 1: Mix 1000 kg of smelting ash containing 13.5% arsenic, 40.7% antimony, 6.4% lead, and 7.9% zinc with 300 kg of sodium carbonate (m 碳酸钠 =30%m 烟灰 ), 600 kg of iron ore with a grade of 59.8% (m Fe :m As =2.66), 600k pulverized coal are mixed evenly, and the mixture is pressed into pellets, dried, and the compressive strength of the dry pellets is higher than 50 N / pellet.

[0031] Step 2: The pellets obtained in Step 1 are fed into the melting equipment and melted in the molten pool at 1200°C for 2 hours, while the nitrogen flow rate is set to 0.2 m³ / h during the melting process.3 / s (0.11m per ton of furnace charge) 3 / s), and hold at the temperature for 40 min after the melting is completed.

[0032] After smelting, the layers were separated, yielding 398.7 kg of slag, containing 19.4% zinc. The antimony-sodium alloy weighed 469.9 kg, containing 80.4% antimony. Its density was 7.41 g / cm³. 3 The iron-arsenic alloy weighs 455.1 kg, with an arsenic content of 28.4% and an iron content of 68.8%. The bottom layer of crude lead weighs 61.4 kg, with a lead content of 96.6%. The smelting ash weighs 4.7 kg, with an arsenic content of 40.8%, an antimony content of 11.5%, a zinc content of 4.3%, and a lead content of 2%.

[0033] The direct recovery rate of arsenic in the entire process is 95.7%, antimony is 92.8%, zinc is 97.9%, and lead is 92.7%. Secondary flue ash can be returned to the batching process for recycling.

[0034] Example 2

[0035] Step 1: Mix 1000 kg of smelting ash containing 45.8% arsenic, 9.2% antimony, 2.9% lead, and 5.9% zinc with 400 kg of sodium carbonate (m 碳酸钠 =40%m 烟灰 ), 4000 kg of red mud iron ore with a grade of 55.5% (m Fe :m As =4.72), 1000 kg of coke powder are mixed evenly, and the mixture is pressed into pellets so that the compressive strength of the dry pellets is higher than 50 N / pellet.

[0036] Step 2: The pellets obtained in Step 1 are fed into the melting equipment and melted in the molten pool at 1400 °C for 3 hours, while the nitrogen flow rate is set to 1.28 m³ / h during the melting process. 3 / s (0.2 m per ton of furnace charge) 3 / s), and hold at the temperature for 30 min after the melting is completed.

[0037] After smelting, 448.6 kg of slag was obtained, with a zinc content of 12.5%. The antimony-sodium alloy weighed 116.4 kg, with an antimony content of 78.2%. Its density was 7.37 g / cm³. 3 The iron-arsenic alloy weighs 2687.5 kg, with an arsenic content of 16.1% and an iron content of 82.8%. The bottom layer of crude lead weighs 28.3 kg, with a lead content of 97.1%. The smelting ash weighs 5.8 kg, with an arsenic content of 61.2%, an antimony content of 8.3%, a zinc content of 5.2%, and a lead content of 3.8%.

[0038] The direct recovery rate of arsenic in the entire process is 94.5%, antimony is 98.9%, zinc is 95.0%, and lead is 98.1%. Secondary flue ash can be returned to the batching process for recycling.

[0039] Example 3

[0040] Step 1: Mix 1000 kg of smelting ash containing 56.5% arsenic, 7.6% antimony, 1.8% lead, and 4.3% zinc with 400 kg of sodium hydroxide (m 氢氧化钠 =40%m 烟灰 ), 1700 kg of pig iron with a purity of 98.1% (m Fe :m As =2.95), 500 kg of heavy oil are mixed evenly, and the mixture is pressed into pellets so that the compressive strength of the dry pellets is higher than 50 N / pellet.

[0041] Step 2: The pellets obtained in Step 1 are fed into the melting equipment and melted in the molten pool at 1100 °C for 2 hours, while the nitrogen flow rate is set to 1.5 m³ / h during the melting process. 3 / s (0.42 m per ton of furnace charge) 3 / s), and hold at the temperature for 60 min after smelting.

[0042] After smelting, 434.1 kg of slag was obtained, containing 9.4% zinc. The antimony-sodium alloy weighed 94.5 kg, containing 77.6% antimony. Its density was 7.55 g / cm³. 3 The iron-arsenic alloy weighs 2294.8 kg, with an arsenic content of 23.4% and an iron content of 71.3%. The bottom layer of crude lead weighs 17.4 kg, with a lead content of 96.6%. The smelting ash weighs 4.8 kg, with an arsenic content of 57.3%, an antimony content of 4.3%, a zinc content of 6.1%, and a lead content of 2.8%.

[0043] The direct recovery rate of arsenic in the entire process is 95.0%, antimony is 96.5%, zinc is 94.9%, and lead is 93.4%. Secondary flue dust can be returned to the batching process for recycling.

[0044] Example 4

[0045] Step 1: Mix 1000 kg of smelting ash containing 22.8% arsenic, 30.9% antimony, 5.7% lead, and 9.9% zinc with 400 kg of sodium hydroxide (m 氢氧化钠 =40%m 烟灰 3000 kg of goethite slag containing 50.1% iron and 4.3% zinc (m Fe :m As=6.59), 800 kg of petroleum coke were mixed evenly, and the mixture was pressed into pellets so that the compressive strength of the dry pellets was higher than 50 N / pellet.

[0046] Step 2: The pellets obtained in Step 1 are fed into the melting equipment and melted in the molten pool at 1300 °C for 1 hour, while the nitrogen flow rate is set to 1 m³ / h during the melting process. 3 / s (0.2 m per ton of furnace charge) 3 / s), and hold at the temperature for 60 min after smelting.

[0047] After smelting, 594.8 kg of slag was obtained, with a zinc content of 37.5%. The antimony-sodium alloy weighed 387.1 kg, with an antimony content of 78.6%. Its density was 7.40 g / cm³. 3 The iron-arsenic alloy weighs 1754.0 kg, with an arsenic content of 12.0% and an iron content of 83.8%. The bottom layer of crude lead weighs 55.5 kg, with a lead content of 98.3%. The smelting ash weighs 6.7 kg, with an arsenic content of 70.4%, an antimony content of 6.3%, a zinc content of 4.5%, and a lead content of 1.3%.

[0048] The direct recovery rate of arsenic in the entire process is 92.3%, antimony is 98.5%, zinc is 97.8%, and lead is 95.7%. Secondary flue ash can be returned to the batching process for recycling.

[0049] Comparative Example 1

[0050] The effect of synergistic melting without the addition of sodium-containing alkaline substances was investigated.

[0051] Comparative Example 1 was essentially the same as Example 1, except that sodium carbonate was not added during the batching process. The smelted iron-arsenic alloy yielded only 371.0 kg, with a significantly reduced arsenic content of 15.6%, and no antimony-sodium alloy layer was observed. The fly ash weight increased to 103.5 kg, with an arsenic content increasing to 68.4%. The direct arsenic recovery rate decreased to 42.9%.

[0052] In Comparative Example 1, no specific amount of sodium carbonate was added during mixing. A large amount of arsenic oxide volatilized into the flue gas, leading to a decrease in the direct arsenic recovery rate, and antimony was not effectively captured by sodium to achieve antimony stratification.

[0053] Comparative Example 2

[0054] The melting effect of materials that were not compressed into briquettes was examined.

[0055] Comparative Example 2 was essentially the same as Example 1, except that the mixture in Comparative Example 2 was not subjected to briquetting. The mass of the iron-arsenic alloy produced by smelting was only 366.8 kg, with an arsenic content of 18.9% and an iron content of 80.1%. The mass of flue dust was significantly increased to 114.2 kg, with an arsenic content of only 57.5%. The direct recovery rate of arsenic during smelting decreased to 51.4%.

[0056] Compared to Example 1, the mixture in Comparative Example 2 was not processed into pellets, and some of the material was absorbed into the flue gas during the feeding process. Furthermore, the powder's effect on arsenic fixation was less than that of pellets, resulting in a lower direct arsenic recovery rate.

[0057] Comparative Example 3

[0058] The smelting effect without nitrogen bottom blowing technology was investigated.

[0059] Comparative Example 3 was essentially the same as Example 1, except that it did not use bottom-blowing nitrogen at a specific flow rate for melting. The mass of the antimony-sodium alloy in the smelting product was 447.6 kg, with an antimony content of 79.9%. The antimony content in the iron-arsenic alloy was 3.8%, higher than the 1.6% in Example 1. The direct antimony recovery rate during the melting process decreased to 87.9%, indicating an increase in antimony loss in the iron-arsenic alloy.

[0060] Compared to Example 1, Comparative Example 3 did not employ a nitrogen bottom-blowing technique with a specific flow rate, resulting in incomplete internal reaction of the melt and difficulty in product stratification. Specifically, the formation of the antimony-sodium alloy layer was incomplete, leading to the loss of some antimony into the iron-arsenic alloy and the coarse lead layer.

Claims

1. A method for preparing iron-arsenic alloys and recovering valuable metals through one-step smelting of arsenic-antimony flue gas, characterized in that: The raw materials, including arsenic-antimony flue ash, sodium-containing alkaline iron slag, and carbonaceous reducing agent, are mixed and pressed into pellets. The resulting pellets are then subjected to reduction smelting. After smelting, the melt is allowed to stand and layered, resulting in a zinc-containing smelting slag layer, an antimony-sodium alloy layer, an iron-arsenic alloy layer, and a bottom layer of crude lead, from top to bottom.

2. The method for preparing iron-arsenic alloy and recovering valuable metals by one-step smelting of arsenic-antimony flue gas according to claim 1, characterized in that: The mass of the sodium-containing alkaline substance is not less than 20% of the mass of the arsenic-antimony-containing flue ash; And / or, The mass of the iron slag is measured as 2.5 to 7 times the mass of iron in the iron slag and the mass of arsenic in the arsenic-antimony flue dust. And / or, The mass of the carbonaceous reducing agent is 30-80% of the mass of arsenic-antimony flue ash.

3. The method for preparing iron-arsenic alloy and recovering valuable metals by one-step smelting of arsenic-antimony flue gas according to claim 2, characterized in that: The sodium-containing alkaline substance includes at least one of sodium carbonate, sodium hydroxide, and alkaline smelting slag from non-ferrous metallurgy.

4. The method for preparing iron-arsenic alloy and recovering valuable metals by one-step smelting of arsenic-antimony flue gas according to claim 2, characterized in that: The iron slag includes at least one of goethite slag, hematite slag, iron ore, scrap iron, and red mud iron beneficiation.

5. The method for preparing iron-arsenic alloy and recovering valuable metals by one-step smelting of arsenic-antimony flue gas according to claim 2, characterized in that: The carbon reducing agent includes at least one of pulverized coal, coke, waste graphite, petroleum coke, charcoal, natural gas, heavy oil, and waste cooking oil.

6. The method for preparing iron-arsenic alloy and recovering valuable metals by one-step smelting of arsenic-antimony flue gas according to claim 1, characterized in that: The compressive strength of the pellets is not less than 50 N / pellet.

7. A method for preparing iron-arsenic alloy and recovering valuable metals by one-step smelting of arsenic-antimony flue gas according to any one of claims 1 to 6, characterized in that: The reduction smelting adopts a nitrogen bottom-blowing enhanced reduction smelting method.

8. The method for preparing iron-arsenic alloy and recovering valuable metals by one-step smelting of arsenic-antimony flue gas according to claim 7, characterized in that: The conditions for the reduction smelting are: temperature of 1000~1400 °C and time of 1~3 h.

9. The method for preparing iron-arsenic alloy and recovering valuable metals by one-step smelting of arsenic-antimony flue gas according to claim 7, characterized in that: During the reduction smelting process, the nitrogen bottom-blowing flow rate is 0.1~0.5 m³ per ton of furnace charge. 3 / s.

10. The method for preparing iron-arsenic alloy and recovering valuable metals by one-step smelting of arsenic-antimony flue gas according to claim 7, characterized in that: The time for the melt to stand and separate into layers is 30-60 minutes.

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