Device and method for preparing arsenic-iron alloy from arsenic oxide and iron oxide

Abstract

The invention discloses a device and a method for preparing an arsenic-iron alloy from arsenic oxide and iron oxide. The device comprises a raw material bin, a mixer, a briquetting machine, a block mass bin, a rotary kiln and a briquetting machine, a raw material conveying belt is arranged below the raw material bin; the tail end extends to the upper part of the feeding hole of the mixer; a discharging hole of the mixer is connected with a feeding hole of the briquetting machine through a mixed material conveying belt; a discharging hole of the briquette pressing machine is connected with a feeding hole of the briquette bin; a discharging opening of the block mass bin is connected with a feeding opening of the rotary kiln through a block mass conveying slide way; a rotary kiln discharge port is connected with the head end of the furnace charge conveying belt; the tail end of the furnace burden conveying belt is connected with a feeding port of the briquetting machine The method comprises the following steps: (1) mixing arsenic trioxide powder with pulverized coal, iron oxide powder and reduced iron powder, pressing into balls, aging and drying; (2) calcining; and (3) forming. The device is reasonable in structure, convenient to operate, low in cost and environmentally friendly. The arsenic-iron alloy obtained by the method is low in leaching amount of arsenic, environment-friendly, energy-saving, simple and convenient in process, low in cost and suitable for industrial production.

Description

Technical Field

[0001] The invention relates to a device and a method for preparing an arsenic-iron alloy, and in particular to a device and a method for preparing an arsenic-iron alloy by using arsenic oxide and iron oxide. Background Art

[0002] During the smelting process of nonferrous metals in my country, such as copper, antimony, gold, lead, zinc, tin and other ores, a large number of arsenic pollution sources will be generated. According to incomplete statistics, my country produces more than 500,000 tons of arsenic slag annually, and has stockpiled more than 2 million tons of arsenic slag. At the same time, due to the toxicity of arsenic, the market for traditional arsenic products has shrunk sharply, causing the price of metallic arsenic to remain low for a long time. Arsenic eventually exists in various hazardous wastes, with high pollution risks. Nonferrous smelting companies are facing tremendous pressure. On the other hand, arsenic is also a resource. How to effectively utilize arsenic as a resource and expand the consumption channels of arsenic resources is of great significance.

[0003] Arsenic-iron alloy is a safe substance that can be used as a counterweight for construction, excavators, elevators, ships, etc. Therefore, research and development of arsenic-iron alloy is ongoing.

[0004] CN117737494A discloses a method for preparing a high-arsenic-containing arsenic-iron alloy, a high-arsenic-containing arsenic-iron alloy and its application, the method comprising the following steps: vacuum ball milling arsenic powder and iron powder under protective atmosphere conditions to obtain arsenic-iron powder; the method requires that the molar ratio of arsenic powder to the iron powder is 0.8-1.5:1; at the same time, the arsenic-iron powder is mixed with a ferrous agent to obtain an alloy base material; the alloy base material is subjected to high-temperature hot pressing and sintering to obtain an arsenic-iron alloy. Although the arsenic-iron alloy obtained by the method is an arsenic-iron alloy with low arsenic loss, i.e., a high-arsenic content, the method requires high-grade raw materials such as high-content arsenic powder (As≥98%) and iron powder (Fe≥98%) as raw materials, and the preparation process is extremely harsh, requiring long-term flipping and shaking under argon atmosphere conditions, vacuum ball milling tanks, normal temperature and pressure, argon protection conditions, and flip shaking machines. Therefore, there are certain limitations to large-scale production of this method, and its production cost is high.

[0005] CN115491534A discloses an arsenic-iron alloy, a preparation method and a resource treatment method, which comprises the following steps: arsenic powder and iron powder are subjected to ball milling treatment under the protection of an inert atmosphere at a molar ratio of 0.1 to 2:1 to obtain a pretreated product; the pretreated product is subjected to vacuum hot pressing sintering treatment to obtain an arsenic-iron alloy; wherein a pressure of 30 to 50 MPa is applied to the pretreated product; the sintering process comprises: raising the pretreated product from room temperature to 400 to 500°C, keeping the temperature for 0.5 to 1 hour, and then raising the pretreated product from 400 to 500°C to 600 to 800°C, keeping the temperature for 0.5 to 1 hour. Although this method can obtain an arsenic-iron alloy with high performance and low leaching toxicity, the method has certain limitations. First, high-content arsenic powder (As≥98%) and iron powder (Fe≥98%) are required as raw materials, and second, the production process is harsh and complicated, such as requiring an inert atmosphere, vacuum hot pressing sintering, etc.

[0006] The above two methods are somewhat inadequate for the treatment of a large number of arsenic-containing materials, such as low-grade arsenic oxide, and the above methods are not suitable for treating a large number of arsenic-containing materials currently existing. Therefore, it is urgent to find a device for preparing arsenic-iron alloy using arsenic oxide and iron oxide, which has a perfect and reasonable structure, is easy to operate, has low manpower and material costs, and is environmentally friendly, and a method for preparing arsenic-iron alloy using arsenic oxide and iron oxide, which can utilize arsenic trioxide and iron oxide raw materials as resources, has low arsenic leaching amount in the obtained arsenic-iron alloy, high arsenic recovery rate, is environmentally friendly and energy-saving, has a simple process, low cost, high production efficiency, and is suitable for industrial production. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a device for preparing arsenic-iron alloy by using arsenic oxide and iron oxide, which has a perfect and reasonable structure, is easy to operate, has low manpower and material costs, and is green and environmentally friendly.

[0008] The technical problem further to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a method for preparing arsenic-iron alloy using arsenic oxide and iron oxide, which can utilize arsenic trioxide and iron oxide raw materials in a resource-based manner, has low arsenic leaching amount in the obtained arsenic-iron alloy, high arsenic recovery rate, environmental protection and energy saving, simple process, low cost, high production efficiency, and is suitable for industrial production.

[0009] The technical solution adopted by the present invention to solve its technical problems is as follows: a device for preparing arsenic-iron alloy with arsenic oxide and iron oxide, comprising a raw material silo, a mixer, a briquette press, a lump silo, a rotary kiln and a briquette press; a raw material conveyor belt is arranged below the raw material silo; the tail end of the raw material conveyor belt extends above the feed port of the mixer; the mixer discharge port is connected to the feed port of the briquette press through the mixing conveyor belt; the briquette press discharge port is connected to the feed port of the lump silo; the lump silo discharge port is connected to the feed port of the rotary kiln through the lump conveying slide; the rotary kiln discharge port is connected to the head end of the charge conveyor belt; the tail end of the charge conveyor belt is connected to the feed port of the briquette press.

[0010] Preferably, the raw material silo is divided into four silos, which are used to contain arsenic trioxide powder, iron oxide powder, coal powder and reduced iron powder respectively. The raw material silo is made of steel.

[0011] Preferably, a raw material silo inlet is provided at the top of the raw material silo, and a raw material silo outlet is provided at the bottom.

[0012] Preferably, the raw material silo discharge port is provided with a discharge valve.

[0013] Preferably, the raw material silo is supported by a support frame.

[0014] Preferably, a meter is provided on the supporting points of the raw material silo and the supporting frame.

[0015] Preferably, the raw material conveyor belt and the mixing material conveyor belt are both made of rubber.

[0016] Preferably, the mixer is a vertical mixer or a horizontal mixer, etc. The mixer is made of stainless steel or ordinary steel.

[0017] Preferably, the briquetting machine is a mechanical briquetting machine. The material of the briquetting machine is cast iron.

[0018] Preferably, the agglomerate silo discharge port is provided with a control valve.

[0019] Preferably, the rotary kiln is built with refractory materials.

[0020] Preferably, the fume outlet of the rotary kiln is connected to the fume inlet of the dust collector.

[0021] Preferably, a dust collecting chamber is provided at the lower portion of the dust collector.

[0022] Preferably, the exhaust gas outlet of the dust collector is connected to the exhaust gas chimney.

[0023] Preferably, the dust collector is an ordinary bag dust collector or a pulse bag dust collector, etc. The dust bag in the dust collector is made of fibers such as polyester, polypropylene or acrylic. The ordinary bag dust collector refers to a bag dust collector without a pulse device and relying on manual shaking of the material.

[0024] Preferably, the exhaust gas chimney is 25 to 35 meters high. The exhaust gas chimney is made of bricks or concrete.

[0025] Preferably, the material of the charge conveyor belt is stainless steel or ordinary steel.

[0026] Preferably, the briquetting machine is a mechanical or hydraulic briquetting machine.

[0027] Preferably, the discharge port of the briquetting machine is connected to a stacking machine.

[0028] Preferably, the palletizer is a mechanical or automated palletizer.

[0029] The working process of the device of the present invention is as follows: arsenic trioxide powder, iron oxide powder, coal powder and reduced iron powder are respectively loaded into four raw material silos, the four raw materials are released onto the raw material conveyor belt through the raw material silo discharge port, the meter measures the weight of each raw material in a reduction manner, when the weight of each raw material in the raw material silo is reduced to a set value, the meter is linked to the corresponding discharge valve to close, the raw material is sent to the mixer through the raw material conveyor belt for mixing, the mixed material discharged from the mixer discharge port is sent to the briquetting machine through the mixing conveyor belt for briquetting, the briquetting blocks are released to the briquetting silo for aging, and then controlled to be released to the rotary kiln for calcination through the control valve of the briquetting silo discharge port, the arsenic-iron alloy powder or block obtained by calcination is sent to the briquetting machine by the charge conveyor belt for briquetting into formed arsenic-iron alloy, and the formed arsenic-iron alloy is stacked by a stacker; wherein, the arsenic-containing smoke dust generated during the calcination process of the rotary kiln is recovered through the dust collector, the arsenic-containing dust is collected in the dust collecting chamber, and the arsenic-free waste gas is discharged through the waste gas chimney.

[0030] The technical solution adopted by the present invention to further solve the technical problem is as follows: a method for preparing arsenic-iron alloy by using arsenic oxide and iron oxide, comprising the following steps: (1) Ball pressing and aging: After mixing arsenic trioxide powder with coal powder, iron oxide powder and reduced iron powder, ball pressing, aging and drying are carried out to obtain aged agglomerates; (2) Calcination: The aged agglomerates obtained in step (1) are fed into a rotary kiln for calcination to obtain arsenic-iron alloy powder or blocks; (3) Molding: The ferroarsenic alloy powder or block obtained in step (2) is molded to obtain an ferroarsenic alloy product.

[0031] The inventive concept of the present invention is: appropriate reducing coal powder is added to arsenic trioxide powder, iron oxide powder and reduced iron powder, and the mixture is mixed, ball-pressed, aged, naturally air-dried, and sent to a rotary kiln for calcination. While the arsenic trioxide powder and the iron oxide powder are reduced to arsenic and iron elements by the reducing coal powder, they form arsenic-iron alloy with the reduced iron powder, and then the arsenic-iron alloy product is obtained by pressing and molding.

[0032] Preferably, in step (1), the mass ratio of arsenic trioxide powder, coal powder, iron oxide powder and reduced iron powder is 1:1.10-1.40:1.80-2.50:0.35-0.50. Although coal powder can reduce arsenic trioxide powder and iron oxide powder, if all iron ore is used, a lot of impurities will be introduced, which will affect the density of arsenic iron alloy, reduce the density of arsenic iron alloy, and further affect the stability of arsenic in arsenic iron alloy, making the grade of arsenic iron alloy poor. The addition of an appropriate amount of reduced iron powder helps to obtain a higher grade arsenic iron alloy while utilizing the oxidized raw material.

[0033] Preferably, in step (1), the mass content of arsenic trioxide in the arsenic trioxide powder is ≥ 95%. The arsenic trioxide powder can be separated from arsenic-containing materials.

[0034] Preferably, in step (1), the particle size of the arsenic trioxide powder is 100-150 mesh.

[0035] Preferably, in step (1), the calorific value of the coal powder is ≥6000 kcal / kg, the mass content of fixed carbon is ≥70%, the mass content of ash is ≤15%, the mass content of water is ≤5%, and the total mass content of the three is <100%. The coal powder is used to reduce arsenic trioxide and iron oxide to arsenic and iron, and the fixed carbon therein is oxidized to carbon monoxide.

[0036] Preferably, in step (1), the particle size of the coal powder is 80-100 mesh.

[0037] Preferably, in step (1), the iron content of the iron oxide powder is 50-60% by weight, and the water content is ≤5% by weight. The iron oxide powder is high-grade iron ore powder.

[0038] Preferably, in step (1), the particle size of the iron oxide powder is 80-100 mesh.

[0039] Preferably, in step (1), the mass content of effective iron in the reduced iron powder is 92-95%.

[0040] Preferably, in step (1), the particle size of the reduced iron powder is 80-100 mesh.

[0041] Preferably, in step (1), the mixing time is 30 to 50 minutes.

[0042] Preferably, in step (1), the ball pressing means: at room temperature and pressure, with a linear specific pressure of 2 to 4 t / cm, the ball pressing is performed for 10 to 20 seconds to form an elliptical agglomerate with a diameter of 20 to 30 mm and a thickness of 25 to 32 mm. If the agglomerate is too dense, it is not conducive to aging and subsequent calcination. If the agglomerate is too loose, it is easy to disperse and is not conducive to aging. In addition, during the calcination process, it will be mixed into one piece, which is not conducive to ventilation and flow, resulting in the reduction reaction being difficult to proceed.

[0043] Preferably, in step (1), the aging temperature is room temperature and the time is 24 to 48 hours. The purpose of the aging is to allow the materials in the pellets to penetrate each other through diffusion and become uniform. If the aging time is too short, the materials in the pellets will not penetrate sufficiently, affecting the subsequent processes. Although the longer the aging time, the better, if the aging time is too long, the production efficiency will be reduced.

[0044] Preferably, in step (1), the drying refers to natural air drying for 48 to 72 hours. Drying is more conducive to increasing the strength of the pellets, accelerating the reaction speed, reducing heat energy, etc.

[0045] Preferably, in step (2), the calcination is a three-stage calcination, the first stage is pre-calcined at 600-780°C for 30-40 minutes, the second stage is high-temperature calcined at 780-850°C for 20-30 minutes, and the third stage is kept at 720-780°C for 10-20 minutes. During the calcination process, arsenic trioxide and iron oxide are reduced by the reducing coal to arsenic and iron, and the elemental arsenic and elemental iron undergo a melting reaction to form an arsenic-iron alloy. In the arsenic-iron alloy, the arsenic-iron alloy has a dense structure and can solidify arsenic, thereby reducing the arsenic leaching rate in the arsenic-iron alloy. In the three-stage calcination, the pre-calcination allows the reaction to proceed gradually, which is beneficial to the formation of the ferroarsenic alloy in the process of continuously obtaining elemental arsenic and elemental iron, and reduces the impurities entrained in the ferroarsenic alloy. If the pre-calcination temperature is too high, the reaction is uneven, and the obtained ferroarsenic alloy contains unreduced arsenic oxide and iron oxide impurities; the high-temperature calcination stage can increase the intensity of the reaction and accelerate the reaction speed; the heat preservation stage is the later stage of the entire ferroarsenic alloy, so that a small amount of arsenic oxide and iron oxide impurities in the generated ferroarsenic alloy are further reduced to synthesize the ferroarsenic alloy, and at the same time, the structure of the generated ferroarsenic alloy is made tighter.

[0046] Preferably, in step (3), the molding temperature is 690-720°C, the total pressure is 1400-1800t, and the time is 20-60s. The specifications of the molding mold are: 200mm *100mm *100mm. The temperature needs to be controlled during the molding process. If the temperature is too high, the material softens and is not easy to mold. If the temperature is too low, the material hardness is too large and is not easy to mold. By controlling the molding pressure, the molding speed can be controlled. If the molding speed is too fast, the molding is not strong. If the molding speed is too slow, the production efficiency is reduced. The molding process parameters are set so that the relative density of the obtained arsenic-iron alloy reaches 5.0-6.8, or even 5.5-6.8. The relative density is 1g / cm2 based on the density of water at 4°C. 3 as a reference density.

[0047] The beneficial effects of the present invention are as follows: (1) The device of the present invention has a perfect and reasonable structure, is easy to operate, has low manpower and material costs, and is green and environmentally friendly; (2) The method of the present invention can make resourceful use of arsenic oxide and iron oxide raw materials. The quality indicators of the obtained arsenic-iron alloy are as follows: relative density of 5.0-6.8, black appearance, compact structure, arsenic content of 23-25%, iron content of 60-65%, uniform composition, and arsenic toxicity test index as low as 2 mg / L, which meets GB5085.3-2007 and HJ / T298 standards; (3) The method of the present invention is environmentally friendly and energy-saving, reducing energy consumption and waste emissions in the production process. The arsenic recovery rate is as high as 99.99%. The process is simple, the cost is low, the production efficiency is high, and it is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic diagram of the overall structure of embodiments 1 to 3 of the device for preparing arsenic-iron alloy by using arsenic oxide and iron oxide according to the present invention. DETAILED DESCRIPTION

[0049] The present invention will be further described below in conjunction with the embodiments and drawings.

[0050] Unless otherwise specified, the raw materials or chemical reagents used in the embodiments of the present invention are obtained through conventional commercial channels.

[0051] A device for preparing arsenic-iron alloy using arsenic oxide and iron oxide Examples 1 to 3 like Figure 1As shown, a device for preparing arsenic-iron alloy with arsenic oxide and iron oxide comprises a raw material silo 1, a mixer 2, a briquetting machine 3, a lump silo 4, a rotary kiln 5 and a briquetting machine 6; a raw material conveyor belt 7 is provided below the raw material silo 1; the tail end of the raw material conveyor belt 7 extends above the feed port 2-1 of the mixer 2; the discharge port 2-2 of the mixer 2 is connected to the feed port 3-1 of the briquetting machine 3 through the mixing conveyor belt 8; the discharge port 3-2 of the briquetting machine 3 is connected to the feed port 4-1 of the lump silo 4; the discharge port 4-2 of the lump silo 4 is connected to the feed port 5-1 of the rotary kiln 5 through the lump conveying slide 4-3; the discharge port 5-2 of the rotary kiln 5 is connected to the head end of the charge conveyor belt 9; the tail end of the charge conveyor belt 9 is connected to the feed port 6-1 of the briquetting machine 6; The raw material silo 1 is divided into four silos, which are used to contain arsenic trioxide powder, iron oxide powder, coal powder and reduced iron powder respectively; the material of the raw material silo 1 is steel; the top of the raw material silo 1 is provided with a raw material silo 1 feed port 1-1, and the bottom is provided with a raw material silo 1 discharge port 1-2; the raw material silo discharge port 1-2 is provided with a discharge valve 1-2-1; the raw material silo 1 is supported by a support frame 1-3; a meter 1-3-1 is provided on the supporting points of the raw material silo 1 and the support frame 1-3; the raw material conveyor belt 7 and the mixing conveyor belt 8 are both made of rubber; the mixer 2 is a vertical mixer; the material of the vertical mixer is stainless steel; the briquetting machine 3 is a mechanical briquetting machine; the material of the mechanical briquetting machine is cast iron; the discharge port 4-2 of the briquetting silo 4 is provided with a control valve 4-2-1; The rotary kiln 5 is built of refractory materials; the smoke outlet 5-3 of the rotary kiln 5 is connected to the smoke inlet 11-1 of the dust collector 11; the dust collector 11 is provided with a dust collecting chamber 11-2 at the lower part; the exhaust gas outlet 11-3 of the dust collector 11 is connected to the exhaust gas chimney 12; the dust collector 11 is a pulse bag dust collector; the dust collecting bag in the pulse bag dust collector is made of polyester fiber; the exhaust gas chimney 12 is 30m high; the exhaust gas chimney 12 is brick-built; the material of the charge conveyor belt 9 is stainless steel; the briquetting machine 6 is a hydraulic briquetting machine; The discharge port 6 - 2 of the briquetting machine 6 is connected to a stacking machine 10 ; the stacking machine 10 is an automatic stacking machine.

[0052] The working process of the device of the present invention is as follows: arsenic trioxide powder, iron oxide powder, coal powder and reduced iron powder are respectively loaded into four raw material silos 1, and the four raw materials are released onto the raw material conveyor belt 7 through the discharge port 1-2 of the raw material silo 1. The meter 1-3-1 measures the weight of each raw material in a decrementing manner. When the weight of each raw material in the raw material silo 1 is reduced to a set value, the meter 1-3-1 is linked to the corresponding discharge valve 1-2-1 to be closed, and the raw materials are sent to the mixer 2 through the raw material conveyor belt 7 for mixing. The mixed material discharged from the discharge port 2-2 of the mixer 2 is mixed. The material conveyor belt 8 is sent to the briquetting machine 3 for briquetting. After the briquetting blocks are released to the briquetting silo 4 for aging, they are controlled to be released to the rotary kiln 5 for calcination through the control valve 4-2-1 of the discharge port 4-2 of the briquetting silo 4. The arsenic-iron alloy blocks obtained by calcination are sent to the briquetting machine 6 by the material conveyor belt 9 for briquetting into formed arsenic-iron alloys. The formed arsenic-iron alloys are stacked by the stacking machine 10. During the calcination process of the rotary kiln 5, arsenic-containing smoke dust generated is recovered by the dust collector 11, and the arsenic-containing dust is collected in the dust collecting chamber 11-2. Arsenic-free waste gas is discharged through the waste gas chimney 12.

[0053] A method for preparing arsenic-iron alloy using arsenic oxide and iron oxide Example 1 (1) Ball pressing and aging: 1000 kg of arsenic trioxide powder (As2O3 mass content of 95.65%, particle size of 100 mesh) was mixed with 1100 kg of coal powder (calorific value of 6000 kcal / kg, fixed carbon mass content of 70.15%, ash mass content of 12.5%, moisture mass content of 2.5%, particle size of 80 mesh), 1800 kg of iron oxide powder (iron ore powder, Fe mass content of 55.45%, moisture mass content of 3.0%, particle size of 80 mesh) and 500 kg of reduced iron powder (effective iron content of 92.15%, particle size of 80 mesh) for 30 min, and then ball pressed for 20 s at room temperature and pressure with a linear pressure of 4 t / cm to form an elliptical agglomerate with a diameter of 20 mm and a thickness of 25 mm. After aging at room temperature for 24 h, the agglomerate was naturally air-dried for 48 h to obtain an aged agglomerate. (2) Calcination: The aged agglomerates obtained in step (1) are fed into a rotary kiln for three-stage calcination, wherein the first stage is pre-calcined at 600-650°C for 40 min, the second stage is high-temperature calcined at 780-820°C for 30 min, and the third stage is kept at 720-750°C for 10 min, to obtain 2426.2 kg of arsenic-iron alloy block material (with a mass content of As of 23.06% and a mass content of Fe of 60.13%), and 228.0 kg of arsenic-containing dust (with a mass content of As of 72.41%) is collected into the dust collecting chamber of the dust collector, and the total recovery rate of arsenic is 99.99%; (3) Molding: The ferroarsenic alloy block obtained in step (2) is molded in a mold of 200 mm * 100 mm * 100 mm at 690° C. and a total pressure of 1600 t for 20 seconds to obtain an ferroarsenic alloy product.

[0054] After testing, the relative density of the ferroarsenic alloy product obtained in the embodiment of the present invention is 5.95, the appearance is black, and the structure is dense.

[0055] According to GB5085.3-2007 and HJ / T298, the arsenic-iron alloy product obtained in the embodiment of the present invention was subjected to a toxic leaching test, and the arsenic toxic leaching test index was 4 mg / L.

[0056] A method for preparing arsenic-iron alloy using arsenic oxide and iron oxide Example 2 (1) Ball pressing and aging: 2000 kg of arsenic trioxide powder (As2O3 mass content of 96.89%, particle size of 120 mesh) was mixed with 2350 kg of coal powder (calorific value of 6500 kcal / kg, fixed carbon mass content of 72.18%, ash mass content of 13.5%, moisture mass content of 3.5%, particle size of 90 mesh), 4000 kg of iron oxide powder (iron ore powder, Fe mass content of 56.18%, moisture mass content of 2.8%, particle size of 90 mesh) and 1000 kg of reduced iron powder (effective iron content of 93.27%, particle size of 90 mesh) for 40 min, and then ball pressed for 15 s at room temperature and pressure with a linear pressure of 3 t / cm to form an elliptical agglomerate with a diameter of 25 mm and a thickness of 29 mm, and then aged at room temperature for 35 h and naturally air-dried for 50 h to obtain an aged agglomerate; (2) Calcination: The aged agglomerates obtained in step (1) are fed into a rotary kiln for three-stage calcination, wherein the first stage is pre-calcined at 700-750°C for 35 min, the second stage is high-temperature calcined at 800-830°C for 25 min, and the third stage is kept at 750-780°C for 15 min to obtain 4892.9 kg of arsenic-iron alloy blocks (with a mass content of 24.91% As and 64.99% Fe), and 340.0 kg of arsenic-containing dust (with a mass content of 73.19%) is collected into the dust collecting chamber of the dust collector. The total recovery rate of arsenic is 99.98%; (3) Molding: The ferroarsenic alloy block obtained in step (2) is molded in a mold of 200 mm * 100 mm * 100 mm at 700° C. and a total pressure of 1500 t for 25 seconds to obtain an ferroarsenic alloy product.

[0057] After testing, the relative density of the ferroarsenic alloy product obtained in the embodiment of the present invention is 6.18, the appearance is black, and the structure is dense.

[0058] According to GB5085.3-2007 and HJ / T298, the arsenic-iron alloy product obtained in the embodiment of the present invention was subjected to a toxic leaching test, and the arsenic toxic leaching test index was 4 mg / L.

[0059] A method for preparing arsenic-iron alloy using arsenic oxide and iron oxide Example 3 (1) Ball pressing and aging: 3000 kg of arsenic trioxide powder (As2O3 mass content of 98.56%, particle size of 150 mesh) was mixed with 4200 kg of coal powder (calorific value of 7000 kcal / kg, fixed carbon mass content of 75.14%, ash mass content of 10.6%, moisture mass content of 4.6%, particle size of 100 mesh), 7500 kg of iron oxide powder (iron ore powder, Fe mass content of 58.26%, moisture mass content of 4.7%, particle size of 100 mesh) and 1050 kg of reduced iron powder (effective iron content of 95.12%, particle size of 100 mesh) for 50 min, and then ball pressed for 10 s at room temperature and pressure with a linear pressure of 2 t / cm2 to form an elliptical agglomerate with a diameter of 30 mm and a thickness of 32 mm, and then aged at room temperature for 48 h and naturally air-dried for 60 h to obtain an aged agglomerate; (2) Calcination: The aged agglomerates obtained in step (1) are fed into a rotary kiln for three-stage calcination, wherein the first stage is pre-calcined at 750-780°C for 30 min, the second stage is high-temperature calcined at 830-850°C for 20 min, and the third stage is kept at 730-760°C for 20 min to obtain 8402.3 kg of arsenic-iron alloy blocks (with a mass content of 23.90% As and 63.89% Fe), and 312 kg of arsenic-containing dust (with a mass content of 74.17%) is collected into the dust collecting chamber of the dust collector. The total recovery rate of arsenic is 99.98%; (3) Molding: The ferroarsenic alloy block obtained in step (2) is molded in a mold of 200 mm * 100 mm * 100 mm at 720° C. and a total pressure of 1400 t for 23 seconds to obtain an ferroarsenic alloy product.

[0060] After testing, the relative density of the ferroarsenic alloy product obtained in the embodiment of the present invention is 6.78, the appearance is black, and the structure is dense.

[0061] According to GB5085.3-2007 and HJ / T298, the arsenic-iron alloy product obtained in the embodiment of the present invention was subjected to a toxic leaching test, and the arsenic toxic leaching test index was 2 mg / L.

[0062] Comparative Example 1 The difference between this comparative example and Example 1 is that: in step (1), 500 kg of reduced iron powder (effective iron content of 92.15%, particle size of 80 mesh) is replaced by 831 kg of iron oxide powder (iron ore powder, iron content of 55.45%, water content of 3.0%, particle size of 80 mesh) with the same iron metal content, and the mass of coal powder is increased to 1450 kg; in step (2), 2521.3 kg of arsenic-iron alloy block material (As content of 22.09% and Fe content of 57.86%) is obtained, and 238.0 kg of arsenic-containing dust (As content of 70.42%) is collected in the dust collecting chamber of the dust collector, and the total recovery rate of arsenic is 99.99%. The rest is the same as Example 1.

[0063] After testing, the relative density of the ferroarsenic alloy product obtained in the comparative example of the present invention is 5.02, the appearance is black, and the structural compactness is poor, which indicates that the composition and structure of the ferroarsenic alloy change due to the change of the arsenic and iron content in the ferroarsenic alloy, which in turn causes the density of the ferroarsenic alloy to decrease.

[0064] According to GB5085.3-2007 and HJ / T298, the arsenic-iron alloy product obtained in the comparative example of the present invention was subjected to a toxic leaching test, and the arsenic toxic leaching test index was 8 mg / L, exceeding the minimum limit of 5 mg / L, indicating that the arsenic-iron content and composition in the arsenic-iron alloy directly affect the toxic leaching test data.

[0065] Comparative Example 2 The difference between this comparative example and Example 2 is that in the calcination step (2), the aged agglomerate obtained in step (1) is sent to a rotary kiln for three-stage calcination, the first stage is pre-calcined at 600-700°C for 35 minutes, the second stage is high-temperature calcined at 800-830°C for 15 minutes, and the third stage is kept at 750-780°C for 6 minutes, and 5317.6 kg of arsenic-iron alloy block material (As mass content is 22.72%, Fe mass content is 59.80%) is obtained, and 367.0 kg of arsenic-containing dust (As mass content is 70.73%) is collected in the dust collecting chamber of the dust collector, and the total recovery rate of arsenic is 99.98%. The rest is the same as Example 2.

[0066] After testing, the relative density of the ferroarsenic alloy product obtained in the comparative example of the present invention is 5.11, the appearance is black, and the structural density is poor, which means that if the high-temperature calcination or the holding time is not enough, some arsenic oxide and iron oxide are difficult to be reduced, and exist in the ferroarsenic alloy as impurities.

[0067] According to GB5085.3-2007 and HJ / T298, the arsenic-iron alloy product obtained in the comparative example of the present invention was subjected to a toxic leaching test, and the arsenic toxic leaching test index was 6 mg / L, exceeding the minimum limit of 5 mg / L. This indicates that arsenic in the non-arsenic-iron alloy existing as an impurity is relatively easy to be leached out, resulting in an increase in the arsenic content in the toxic leaching test.

[0068] Comparative Example 3 The difference between this comparative example and Example 3 is that in step (3), the total pressure is 1000t. The rest is the same as Example 3.

[0069] After testing, the relative density of the ferroarsenic alloy product obtained in the comparative example of the present invention is 4.56, the appearance is black, and the structural density is poor, which means that the ferroarsenic alloy needs a certain pressure to be pressed into a dense block to meet the product requirements.

[0070] According to GB5085.3-2007 and HJ / T298, the arsenic-iron alloy product obtained in the comparative example of the present invention was subjected to a toxic leaching test, and the arsenic toxic leaching test index was 2 mg / L, indicating that as long as the arsenic-iron alloy is generated, the molding operation does not affect the arsenic solubility in the arsenic-iron alloy.

Claims

1. A device for preparing arsenic-iron alloy using arsenic oxide and iron oxide, characterized in that: It includes a raw material silo, a mixer, a briquette machine, a lump silo, a rotary kiln and a briquette machine; a raw material conveyor belt is arranged under the raw material silo; the tail end of the raw material conveyor belt extends to above the feed port of the mixer; the discharge port of the mixer is connected with the feed port of the briquette machine through the mixing conveyor belt; the discharge port of the briquette machine is connected with the feed port of the lump silo; the discharge port of the lump silo is connected with the feed port of the rotary kiln through the lump conveying slide; the discharge port of the rotary kiln is connected with the head end of the charge conveyor belt; the tail end of the charge conveyor belt is connected with the feed port of the briquette machine.

2. The device for preparing arsenic-iron alloy by using arsenic oxide and iron oxide according to claim 1, characterized in that: The raw material silo is divided into four silos; a raw material silo inlet is provided at the top of the raw material silo, and a raw material silo outlet is provided at the bottom; a discharge valve is provided at the raw material silo outlet; the raw material silo is supported by a support frame; a meter is provided at the supporting point of the raw material silo and the support frame; the mixer is a vertical mixer or a horizontal mixer; the briquetting machine is a mechanical briquetting machine; a control valve is provided at the briquetting silo outlet.

3. The device for preparing arsenic-iron alloy by using arsenic oxide and iron oxide according to claim 1 or 2, characterized in that: The smoke outlet of the rotary kiln is connected to the smoke inlet of the dust collector; a dust collecting chamber is provided at the lower part of the dust collector; the exhaust gas outlet of the dust collector is connected to the exhaust gas chimney; the dust collector is an ordinary bag dust collector or a pulse bag dust collector; the briquetting machine is a mechanical or hydraulic briquetting machine.

4. The device for preparing arsenic-iron alloy by using arsenic oxide and iron oxide according to claim 1 or 2, characterized in that: The discharge port of the briquetting machine is connected to a stacking machine; the stacking machine is a mechanical or automatic stacking machine.

5. The device for preparing arsenic-iron alloy by using arsenic oxide and iron oxide according to claim 3, characterized in that: The discharge port of the briquetting machine is connected to a stacking machine; the stacking machine is a mechanical or automatic stacking machine.

6. A method for preparing arsenic-iron alloy by using arsenic oxide and iron oxide based on the device according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Ball pressing and aging: After mixing arsenic trioxide powder with coal powder, iron oxide powder and reduced iron powder, ball pressing, aging and drying are carried out to obtain aged agglomerates; (2) Calcination: The aged agglomerates obtained in step (1) are fed into a rotary kiln for calcination to obtain arsenic-iron alloy powder or blocks; (3) Molding: The ferroarsenic alloy powder or block obtained in step (2) is molded to obtain an ferroarsenic alloy product.

7. The method for preparing ferroarsenic alloy by using arsenic oxide and iron oxide according to claim 6, characterized in that: In step (1), the mass ratio of the arsenic trioxide powder, coal powder, iron oxide powder and reduced iron powder is 1:1.10-1.40:1.80-2.50:0.35-0.50; the mass content of arsenic trioxide in the arsenic trioxide powder is ≥95%; the particle size of the arsenic trioxide powder is 100-150 mesh; the calorific value of the coal powder is ≥6000 kcal / kg, the mass content of fixed carbon is ≥70%, the mass content of ash is ≤15%, the mass content of water is ≤5%, and the total mass content of the three is <100%; the particle size of the coal powder is 80-100 mesh; the iron in the iron oxide powder is ≤100%; the ... in the arsenic trioxide powder is ≥100%; the arsenic trioxide in the arsenic trioxide powder is ≥95%; the particle size of the arsenic trioxide in the arsenic trioxide powder is 100-150 mesh; the arsenic trioxide in the arsenic trioxide powder is ≥95%; the arsenic trioxide in the arsenic trioxide powder is ≥9 The mass content of iron oxide is 50-60%, and the mass content of water is ≤5%; the particle size of the iron oxide powder is 80-100 mesh; the mass content of effective iron in the reduced iron powder is 92-95%; the particle size of the reduced iron powder is 80-100 mesh; the mixing time is 30-50min; the ball pressing refers to: at room temperature and pressure, the linear pressure is 2-4t / cm, the ball pressing is 10-20s to form an elliptical agglomerate with a diameter of 20-30mm and a thickness of 25-32mm; the aging temperature is room temperature and the time is 24-48h; the drying refers to natural air drying for 48-72h.

8. The method for preparing ferroarsenic alloy by using arsenic oxide and iron oxide according to claim 6 or 7, characterized in that: In step (2), the calcination is a three-stage calcination, the first stage is pre-calcination at 600-780°C for 30-40 minutes, the second stage is high-temperature calcination at 780-850°C for 20-30 minutes, and the third stage is kept at 720-780°C for 10-20 minutes.

9. The method for preparing ferroarsenic alloy by using arsenic oxide and iron oxide according to claim 6 or 7, characterized in that: In step (3), the molding temperature is 690-720°C, the total pressure is 1400-1800t, and the time is 20-60s.

10. The method for preparing ferroarsenic alloy by using arsenic oxide and iron oxide according to claim 8, characterized in that: In step (3), the molding temperature is 690-720°C, the total pressure is 1400-1800t, and the time is 20-60s.

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