阅读说明：本技术 一种粗白砷制备金属砷的工艺及其设备 (Process and equipment for preparing metal arsenic from crude white arsenic ) 是由 曲胜利 董准勤 陈涛 曲超 姜培胜 张伟 马永军 孙海明 刘元辉 邹琳 解维平 于 2019-10-22 设计创作，主要内容包括：本发明提供了一种粗白砷制备金属砷的工艺及其设备,包括以下工艺步骤：含As<Sub>2</Sub>O<Sub>3</Sub>≥90%的粗三氧化二砷烟灰经过600℃～700℃挥发得到三氧化二砷蒸汽,三氧化二砷蒸汽经过装有被加热至700℃～800℃机制炭的还原炉被还原为砷蒸汽,砷蒸汽通过350℃～420℃的结晶器冷凝为含As≥99.5%金属砷。该工艺将微波冶金技术应用粗白砷制备金属砷工艺中,具有生产成本低、热效率高,环保节能,产品品质好。设备自动化程度高,生产效率高等显著特点。(The invention provides a process and equipment for preparing metal arsenic from crude white arsenic, which comprises the following process steps: containing As 2 O 3 Volatilizing more than or equal to 90 percent of coarse arsenic trioxide ash at the temperature of 600-700 ℃ to obtain arsenic trioxide steam, reducing the arsenic trioxide steam into arsenic steam through a reduction furnace filled with machine-made carbon heated to the temperature of 700-800 ℃, and condensing the arsenic steam into metal arsenic containing more than or equal to 99.5 percent of As through a crystallizer at the temperature of 350-420 ℃. The process applies the microwave metallurgical technology to the process of preparing the metal arsenic from the crude white arsenic, and has the advantages of low production cost, high thermal efficiency, environmental protection, energy conservation and good product quality. The equipment has the remarkable characteristics of high automation degree, high production efficiency and the like.)

1. A process for preparing metal arsenic from crude white arsenic is characterized by comprising the following steps:

a. microwave distillation: heating a microwave distillation furnace to 600-700 ℃, protecting the feeding and slag discharging positions of the microwave distillation furnace by nitrogen, starting a transmission chain plate of the microwave distillation furnace, adding crude white arsenic into a hopper, spreading the crude white arsenic on the chain plate of the microwave distillation furnace by a packing auger, conveying the crude white arsenic into a microwave heating area along with the transmission of the chain plate to volatilize, conveying volatilized arsenic trioxide steam into a reduction furnace through a flue gas pipeline, cooling the residual arsenic trioxide residues, and discharging the cooled residual arsenic trioxide residues to an arsenic residue ash hopper through an arsenic residue discharge packing auger;

b. hot carbon reduction: a reducing furnace is lined with a quartz tube, machine-made charcoal is filled in the quartz tube, the quartz tube is heated to 700-800 ℃ by microwave, arsenic trioxide steam entering the quartz tube is reduced into simple substance arsenic steam by charcoal or carbon monoxide when passing through a carbon layer, the arsenic steam enters a metal arsenic crystallizer, and machine-made charcoal ash is discharged by a charcoal ash auger at the bottom of the reducing furnace;

c. cooling and crystallizing: the metal arsenic crystallizer consists of stainless steel crystallizer tubes, a rapping cleaning device is arranged, the temperature of the stainless steel tubes is maintained at 350-420 ℃ during operation, when simple substance arsenic steam slowly enters the tubes, the temperature is reduced and crystallization is converted into metal arsenic crystals, the rapping cleaning device is started to clean the metal arsenic crystals, the metal arsenic is collected at the bottom of the stainless steel tubes, metal arsenic products firstly enter a buffer bin and then enter a collection bin to be discharged, and nitrogen protection is introduced into each section for preventing the metal arsenic from being oxidized.

2. The process for preparing metallic arsenic from crude white arsenic As claimed in claim 1, wherein the distillation temperature in step a is 620-680 ℃, and the crude white arsenic contains As₂O₃The pressure of the outlet of the distillation furnace is more than or equal to 90 percent, the pressure of the outlet of the distillation furnace is between 10 and 50Pa, and the flow of nitrogen introduced into the feed inlet and the slag discharge port of the distillation furnace is between 0.5 and 2L/min, so that oxygen is prevented from entering the distillation furnace.

3. The process for preparing metallic arsenic from crude white arsenic as claimed in claim 1, wherein in step b, the reduction temperature is 720-760 ℃, the fixed carbon content of machine-made charcoal is not less than 85%, the outlet pressure of the distillation furnace is-60 Pa-0 Pa, and the flow rate of nitrogen is 0.5L/min-2L/min through a charcoal adding port and a charcoal ash discharging port of the reduction furnace, so as to prevent oxygen from entering the reduction furnace.

4. The process for preparing metallic arsenic from crude white arsenic as claimed in claim 1, wherein in step c, the crystallization temperature is 370-400 ℃, the outlet pressure of the crystallizer is-100 to-50 Pa, and the nitrogen flow is introduced into the crystallizer product collection bin at 0.5-2L/min to prevent metallic arsenic from being oxidized.

5. The equipment for preparing the metal arsenic from the crude white arsenic according to any one of claims 1 to 4 comprises a microwave distillation furnace (1), a reduction furnace (2) and a crystallizer (3), and is characterized in that a microwave generator I (13) is arranged in the microwave distillation furnace (1), a distillation furnace transmission chain plate (14) is arranged above the microwave generator I (13), a feeding auger (11) is arranged above the microwave distillation furnace (1), a feeding ash hopper (12) is arranged above the feeding auger (11), a water cooling device (15) and an arsenic slag discharging auger (16) are arranged at the tail end of the microwave distillation furnace (1), and an arsenic slag ash hopper (17) is arranged below the arsenic slag discharging auger (16); the microwave distillation furnace (1) is connected with the bottom of a reduction furnace (2) through a flue gas pipeline (4), the inner lining of the reduction furnace (2) is a quartz tube, charcoal is filled in the quartz tube, a microwave generator II (25) is arranged on the outer side of the reduction furnace (2), an exhaust port above the reduction furnace (2) is connected with a crystallizer (3) through a steam pipeline (5), a pneumatic gate valve I (23) is arranged above the exhaust port of the reduction furnace, a charcoal ash adding hopper (24) is arranged above the pneumatic gate valve I (23), a charcoal ash discharging port below the reduction furnace (2) is provided with a charcoal ash auger (21), and a charcoal ash hopper (22) is arranged below one side of the charcoal ash auger (21); be equipped with crystallizer tubulation (3) on crystallizer (3), crystallizer tubulation (3) are connected with rapping device (34), and crystallizer tubulation (3) bottom is equipped with collection storehouse (35), and collection storehouse (35) below is equipped with pail pack (31), is equipped with pneumatic push-pull valve II (32) on collection storehouse (35).

Technical Field

The invention belongs to the technical field of microwave metallurgy, and particularly relates to a process and equipment for preparing metal arsenic from crude white arsenic.

Background

The preparation of simple substance arsenic, the prior art at home and abroad mainly comprises: hydrogen reduction, carbon reduction and thermal decomposition of arsenopyrite. The hydrogen replacement method uses a reducing agent as hydrogen, and has explosion risk. The united states patent US3,567,379 proposes a reduction process using ammonia gas as a reducing agent, the process utilizes hydrogen gas produced by ammonia gas decomposition to reduce arsenic trioxide to produce arsenic, the process and equipment are complex, the energy consumption is large, and the cost is high; the carbon reduction method is divided into two types, one is that arsenic trioxide and carbon are mixed, heated and reduced in a crucible or an electric furnace, and then condensed and collected, and the process has low direct yield, poor product quality, large raw material loss, serious environmental pollution and large investment. One is that arsenic trioxide is not mixed with carbon, and is divided into two layers in a stainless steel vertical tank, the lower layer is laid with arsenic trioxide powder, the upper layer is laid with carbon, the outer side of the vertical tank is heated by resistance wire, the upper and lower parts are respectively heated, so that the arsenic trioxide steam is reduced into arsenic steam by the red-hot carbon layer (the temperature of the carbon layer is controlled to be 750-800 ℃), and the arsenic steam is condensed into metal arsenic product in the condenser at the upper part of the furnace body. In our national patents (ZL 89101045.9, 92110735.8), charcoal is placed in a hearth reducing region of an internal electric furnace under the condition of micro negative pressure, arsenic trioxide is gradually volatilized, reduced into metal arsenic through a glowing carbon layer, and condensed to obtain about 99% of metal arsenic. The process is simple and reliable, has strong raw material adaptability, but has the problems of serious corrosion of the furnace body, poor operation environment, high labor intensity, high production cost and the like.

Compared with the process, the three processes of arsenic trioxide distillation, carbon reduction and metal arsenic crystallization are independent, microwave heating is adopted, feeding and deslagging are all automatically controlled, the arsenic-containing material is not contacted by people, and the process has the advantages of high automation degree, high direct yield, environmental friendliness, low labor intensity, low operation cost and the like, and has no relevant reports at home and abroad.

Disclosure of Invention

The invention provides a process for preparing metal arsenic from crude white arsenic and equipment thereof to solve the problems.

The technical scheme of the invention is realized as follows: a process for preparing metal arsenic from crude white arsenic comprises the following steps:

a. microwave distillation: heating a microwave distillation furnace to 600-700 ℃, protecting the feeding and slag discharging positions of the microwave distillation furnace by nitrogen, starting a transmission chain plate of the microwave distillation furnace, adding crude white arsenic into a hopper, spreading the crude white arsenic on the chain plate of the microwave distillation furnace by a packing auger, conveying the crude white arsenic into a microwave heating area along with the transmission of the chain plate to volatilize, conveying volatilized arsenic trioxide steam into a reduction furnace through a flue gas pipeline, cooling the residual arsenic trioxide residues, and discharging the cooled residual arsenic trioxide residues to an arsenic residue ash hopper through an arsenic residue discharge packing auger;

b. hot carbon reduction: a reducing furnace is lined with a quartz tube, machine-made charcoal is filled in the quartz tube, the quartz tube is heated to 700-800 ℃ by microwave, arsenic trioxide steam entering the quartz tube is reduced into simple substance arsenic steam by charcoal or carbon monoxide when passing through a carbon layer, the arsenic steam enters a metal arsenic crystallizer, and machine-made charcoal ash is discharged by a charcoal ash auger at the bottom of the reducing furnace;

c. cooling and crystallizing: the metal arsenic crystallizer consists of stainless steel crystallizer tubes, a rapping cleaning device is arranged, the temperature of the stainless steel tubes is maintained at 350-420 ℃ during operation, when simple substance arsenic steam slowly enters the tubes, the temperature is reduced and the simple substance arsenic steam is crystallized and converted into metal arsenic crystals, the rapping cleaning device is started to clean the metal arsenic crystals, the metal arsenic is collected at the bottom of the stainless steel tubes, the metal arsenic products firstly enter a buffer bin and then enter a collection bin to be discharged, and nitrogen protection is introduced into each section for preventing the metal arsenic from being oxidized;

preferably, the distillation temperature in the step a is 620-680 ℃, and the crude white arsenic contains As₂O₃The pressure of the outlet of the distillation furnace is more than or equal to 90 percent, the pressure of the outlet of the distillation furnace is between 10 and 50Pa, and the flow of nitrogen introduced into the feed inlet and the slag discharge port of the distillation furnace is between 0.5 and 2L/min, so that oxygen is prevented from entering the distillation furnace;

preferably, in the step b, the reduction temperature is 720-760 ℃, the fixed carbon content of machine-made charcoal is not less than 85%, the pressure at the outlet of the distillation furnace is-60 Pa-0 Pa, and the flow rate of nitrogen introduced into a charcoal adding port and a charcoal discharging ash port of the reduction furnace is 0.5L/min-2L/min, so that oxygen is prevented from entering the reduction furnace;

preferably, in the step c, the crystallization temperature is 370-400 ℃, the outlet pressure of the crystallizer is-100 Pa-50 Pa, and the nitrogen flow rate in the crystallizer product collection bin is 0.5-2L/min, so as to prevent the metal arsenic from being oxidized;

an apparatus for preparing metal arsenic from crude white arsenic comprises a microwave distillation furnace, a reduction furnace and a crystallizer, wherein a microwave generator I is arranged in the microwave distillation furnace, a distillation furnace transmission chain plate is arranged above the microwave generator I, a feeding auger is arranged above the microwave distillation furnace, a feeding ash hopper is arranged above the feeding auger, a water cooling device and an arsenic slag discharging auger are arranged at the tail end of the microwave distillation furnace, and an arsenic slag ash hopper is arranged below the arsenic slag discharging auger; the microwave distillation furnace is connected with the bottom of the reduction furnace through a flue gas pipeline, the inner lining of the reduction furnace is a quartz tube, charcoal is filled in the quartz tube, a microwave generator II is arranged outside the reduction furnace, an exhaust port above the reduction furnace is connected with the crystallizer through a steam pipeline, a pneumatic gate valve I is arranged above the exhaust port of the reduction furnace, a charcoal ash adding hopper is arranged above the pneumatic gate valve I, a charcoal ash auger is arranged below a charcoal ash discharge port below the reduction furnace, and a charcoal ash hopper is arranged below one side of the charcoal ash auger; be equipped with the crystallizer tubulation on the crystallizer, the crystallizer tubulation is connected with rapping device, and crystallizer tubulation bottom is equipped with the collection storehouse, and the collection storehouse below is equipped with the pail pack, is equipped with pneumatic gate valve II on the collection storehouse.

The invention has the beneficial effects that: compared with other processes, the process has the following advantages:

(1) the distillation furnace and the reduction furnace are heated by microwaves, so that the heat efficiency is high, the production cost can be reduced, and the production cost of the metal arsenic is reduced from 7000 yuan/t to 8000 yuan/t to 3000 yuan/t to 4000 yuan/t;

(2) the reduction furnace adopts a quartz inner container, and the outside is heated by microwave, so that the contact reaction of charcoal and stainless steel is avoided to corrode a furnace shell, and the service life of the furnace body is prolonged;

(3) the three processes of distillation, reduction and crystallization are completed in three independent reactors, raw materials of crude white arsenic and arsenic-discharging slag are added into a distillation furnace, charcoal and carbon-discharging ash are added into a reduction furnace, and the metal arsenic products collected by a crystallizer are not interfered with each other and have no influence, so that the continuous production of preparing the metal arsenic from the crude white arsenic can be realized;

(4) the equipment has high automation degree, manual furnace reversing and feeding, residue cleaning and metal arsenic product collection are not needed, and the working environment of workers is good;

(5) and nitrogen is introduced into the feeding, deslagging and product collecting positions for sealing, thereby preventing the metal arsenic from being oxidized and ensuring the product quality.

Drawings

FIG. 1 is a process flow diagram of the present invention;

FIG. 2 is a schematic diagram of the apparatus of the present invention.

Description of the parts: 1. the device comprises a microwave distillation furnace, 11 parts of a feeding auger, 12 parts of a feeding ash hopper, 13 parts of a microwave generator I and 14 parts of a distillation furnace transmission chain plate, 15 parts of a water cooling device, 16 parts of an arsenic slag discharging auger, 17 parts of an arsenic slag ash hopper, 2 parts of a reduction furnace, 21 parts of a carbon ash auger, 22 parts of a carbon ash hopper, 23 parts of a pneumatic gate valve I and 24 parts of a carbon ash hopper, 25 parts of a microwave generator II, 3 parts of a crystallizer, 31 parts of a packing barrel, 32 parts of a pneumatic gate valve II, 33 parts of a crystallizer tube, 34 parts of a rapping device, 35 parts of a collecting bin, 4 parts of a flue gas pipeline, 5 parts of a steam pipeline.

Detailed Description

For a better understanding and practice, the present invention is described in detail below with reference to the following examples.