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Method for preparing raw arsenic by vacuum carbon thermal reduction of arsenic trioxide

A technology of arsenic trioxide and carbon heat, applied in the field of thermal reduction pyrometallurgy, can solve the problems of difficult control of arsenic reduction atmosphere, corrosion of arsenic to shaft furnace, high production cost, etc., and achieve the effects of no pollution to the environment, high reduction rate and easy operation

Inactive Publication Date: 2012-01-18
KUNMING UNIV OF SCI & TECH +1
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Problems solved by technology

But above-mentioned two kinds of methods are that arsenic corrodes the shaft furnace seriously at high temperature, and the production cost is high; at the same time, because it is carried out under normal pressure or slight negative pressure, it is difficult to control the arsenic reduction atmosphere, and the arsenic after reduction is easy to be oxidized again, Low reduction rate
[0004] Compared with the above method, the present invention uses the carbon layer to reduce the arsenic trioxide vapor under the ambient pressure of 10-200 Pa, which has the characteristics of simple process flow, high reduction rate, and environmental friendliness, and no relevant reports at home and abroad have been seen yet.

Method used

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  • Method for preparing raw arsenic by vacuum carbon thermal reduction of arsenic trioxide

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Embodiment 1

[0012] Embodiment 1 puts 200g charcoal into the reducing agent layer of the vacuum furnace, arsenic ash (As 2 o 3 >90%) 500g into the volatilization crucible of the vacuum furnace, turn on the vacuum system, start to heat up when the pressure is stable (10-12Pa), and raise the temperature of the charcoal layer to 600°C at a speed of 20°C / min. At this time, the pressure in the furnace reaches 31Pa ; Then heat the arsenic trioxide to 400°C. At this time, the pressure in the furnace is 97Pa, and the volatilization temperature is maintained for 4 hours. During the process, the pressure in the furnace fluctuates in the range of 14-186Pa. When the pressure in the furnace is stabilized to about 14Pa, turn off the heating system and wait for natural cooling Finally, the vacuum furnace was opened, and the solid crude arsenic was taken out from the condenser with a purity of 95.3%.

Embodiment 2

[0013] Embodiment 2 1000g coke is put into the reducing agent layer of vacuum furnace, arsenic ash (As 2 o 3 >90%) 2000g into the volatilization crucible of the vacuum furnace, turn on the vacuum system, start to heat up when the pressure is stable (15-18Pa), and raise the temperature of the charcoal layer to 700°C at a speed of 15°C / min, at this time the pressure in the furnace reaches 35Pa ; Then heat the arsenic trioxide to 350°C. At this time, the pressure in the furnace is 104Pa, and the volatilization temperature is maintained for 8 hours. During the process, the pressure in the furnace fluctuates in the range of 21-162Pa. When the pressure in the furnace is stabilized to about 21Pa, turn off the heating system and wait for natural cooling Finally, the vacuum furnace was opened, and the solid crude arsenic was taken out from the condenser with a purity of 96.7%.

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Abstract

The invention relates to a method for preparing raw arsenic by vacuum carbon thermal reduction of arsenic trioxide. The preparing technology comprises the following steps of: heating a reducing agent to 500-900 DEG C at the speed of 10-20 DEG C / minute by taking charcoal or coke as the reducing agent at the ambient pressure of 10-200Pa; then heating arsenic trioxide to 300-500 DEG C, thus the volatilized arsenic trioxide is reduced after passing through reducing agent layers from bottom to top, thus arsenic steam is obtained; and condensing the arsenic steam into solid raw arsenic after the arsenic steam enters the condenser at 50-200 DEG C. The technology process is simple, the reduction temperature is low, the process is convenient to operate, the reduction ratio is high, and the whole reaction process is carried out in vacuum and has no pollution to the environment.

Description

technical field [0001] The invention belongs to the technical field of thermal reduction pyrometallurgy, and in particular provides a method for preparing crude arsenic by vacuum carbothermal reduction of arsenic trioxide. Background technique [0002] Arsenic is a carcinogen that is toxic to the human body and other organisms, and its fatal dose of acute poisoning is 0.2-0.6g. As one of the "five poisonous" elements (As, Hg, Cd, Pb, Cr), arsenic has many valence states (-3, 0, +3, +5), and is often Arsenic exists in +3 valence and +5 valence state, and the toxicity of arsenic in different valence states is very different. Among them, the arsenic compound existing in +3 valence state is highly toxic, and its toxicity is the most harmful, such as "arsenic" (As 2 o 3 ) toxicity has been well known since ancient times. The toxicity of +5-valent arsenic is also very high; while elemental arsenic is insoluble in water and generally harmless. In industry, arsenic is the raw ma...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B30/04
Inventor 杨斌王炜徐宝强杨成林刘大春戴永年邓勇熊恒刘新阳秦博郁青春曲涛马文会姚耀春
Owner KUNMING UNIV OF SCI & TECH
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