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A kind of supercritical water treatment method of arsenic sulfide slag

A technology for supercritical water and treatment methods, which is applied in chemical instruments and methods, sulfur compounds, arsenic oxide/arsenic hydroxide/oxyacid arsenic, etc. , long reaction time and other problems, to achieve the effect of reducing reagent consumption, avoiding secondary pollution and improving utilization rate

Active Publication Date: 2020-04-07
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Chinese patent CN102115166B discloses a method for preparing arsenic trioxide from arsenic sulfide slag. After three times of filtration (filtering with sodium hydroxide, filtration with concentrated sulfuric acid, and filtration with concentrated sulfuric acid and sodium sulfide), purified arsenic sulfide is obtained. , the follow-up reaction process also needs to add arsenic acid, oxygen, sulfur dioxide, the process is more cumbersome
Chinese patent CN102151690B discloses a method for treating arsenic sulfide slag. The arsenic sulfide slag is added to an inorganic flocculant, and then solid powder adsorbent and asbestos wool are sequentially added to complete the solidification of the arsenic sulfide slag, which does not realize the recovery of arsenic resources.
Chinese patent CN103388076B discloses a method for recovering elemental arsenic from arsenic sulfide slag, which involves adding water, sodium hydroxide, and hydrogen peroxide in sequence, and reacting for 6 hours, then heating and concentrating, adjusting pH with concentrated hydrochloric acid, and adding stannous chloride. Reaction for 8 hours, and the final stage uses solid-liquid separation and drying to obtain elemental arsenic. There are many kinds of reagents and the reaction time is long
Chinese patent CN105963902A discloses a method for the harmless treatment of arsenic sulfide slag, which is followed by adding water, sodium sulfide, oxidant, iron salt (aluminum salt) and cement. After the above process is completed, it is cured for 3 to 15 days, and finally solidified and harmless chemical treatment, the maintenance process is long, and the recovery and utilization of arsenic resources have not been realized

Method used

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Embodiment 1: the mass percentage of arsenic in the arsenic sulfide slag in this embodiment is 45%, and also contains a small amount of heavy metals such as copper, iron, lead, chromium, cadmium in the arsenic sulfide slag;

[0022] A supercritical water treatment method for arsenic sulfide slag, the specific steps are:

[0023] Add water, excess oxidant (oxygen), arsenic sulfide slag, and sulfur-containing additives (sulfur dioxide) into a high-temperature and high-pressure reactor to obtain a reaction system. Reach the supercritical state and react for 105 minutes to obtain the reaction product system, in which the temperature of the supercritical state is 378°C and the pressure is 27.5Mpa; the reaction product system in the high-temperature and high-pressure reactor is cooled to a temperature of 95°C, and the solid-liquid separation obtains solid diarsenic trioxide and liquid product, the liquid product is a sulfuric acid solution containing heavy metal ions such as ...

Embodiment 2

[0026] Embodiment 2: the mass percent of arsenic in the arsenic sulfide slag in this embodiment is 55%, and the arsenic sulfide slag also contains a small amount of heavy metals such as copper, iron, lead, chromium, and cadmium;

[0027] Add water, excess oxidant (hydrogen peroxide), arsenic sulfide slag, and sulfur-containing additives (sulfurous acid) into a high-temperature and high-pressure reactor to obtain a reaction system. The system reaches a supercritical state and reacts for 35 minutes to obtain a reaction product system, in which the temperature of the supercritical state is 420°C and the pressure is 45Mpa; the reaction product system in the high-temperature and high-pressure reactor is cooled to a temperature of 90°C, and solid-liquid separation obtains solid diarsenic trioxide and liquid products, the liquid products are sulfuric acid solutions containing heavy metal ions such as copper, iron, lead, chromium, cadmium, etc.; the mass ratio of water to arsenic sulfi...

Embodiment 3

[0030] Embodiment 3: the mass percent of arsenic in the arsenic sulfide slag in this embodiment is 53%, and the arsenic sulfide slag also contains a small amount of heavy metals such as copper, iron, lead, chromium, and cadmium;

[0031] Add water, excess oxidant (oxygen), arsenic sulfide slag, and sulfur-containing additives (sulfuric acid) into a high-temperature and high-pressure reactor to obtain a reaction system. Reach the supercritical state and react for 75 minutes to obtain the reaction product system, in which the temperature of the supercritical state is 455°C and the pressure is 22.5Mpa; the reaction product system in the high-temperature and high-pressure reactor is cooled to a temperature of 85°C, and the solid-liquid separation obtains solid diarsenic trioxide and liquid product, the liquid product is a sulfuric acid solution containing heavy metal ions such as copper, iron, lead, chromium, cadmium; the mass ratio of water to arsenic sulfide slag is 8:1, the sulf...

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Abstract

The invention relates to a supercritical water treatment method for arsenic sulfide slag and belongs to the technical field of waste slag treatment. According to the supercritical water treatment method for the arsenic sulfide slag, water, excess oxidants, the arsenic sulfide slag and a sulfur-containing additive are added into a high-temperature and high-pressure reaction kettle, the high-temperature and high-pressure reaction kettle is sealed, then heating and pressurizing are carried out till a reaction system in the high-temperature and high-pressure reaction kettle reaches a supercriticalstate, a reaction is carried out for 15-105 min, the high-temperature and high-pressure reaction kettle relieves pressure quickly when the temperature of the supercritical state is 460-680 DEG C, a reaction product system is subjected to gas-solid separation, the solid product is heavy metal oxide, gas of the reaction product system is cooled, gaseous arsenic trioxide is converted into solid arsenic trioxide and settles, cooling is further carried out, and the liquid product is a sulfuric acid solution; and when the temperature of the supercritical state is 378-460 DEG C (excluding 460 DEG C), the reaction product system in the high-temperature and high-pressure reaction kettle is cooled to be 100 DEG C or below, and after solid-liquid separation is carried out, the solid product is arsenic trioxide while the liquid product is a sulfuric acid solution containing metal ions.

Description

technical field [0001] The invention relates to a supercritical water treatment method for arsenic sulfide slag, belonging to the technical field of waste slag treatment. Background technique [0002] As a persistent pollutant, arsenic-containing waste slag has been hoarded and stored for a long time. With the accumulation of high-concentration arsenic-containing waste, the stacked arsenic-containing solid waste has caused serious damage to the local soil and water environment. Sudden hidden dangers caused serious pollution, and the phenomenon of endangering people's life and health is becoming more and more serious. In order to prevent secondary pollution, the treatment of arsenic-containing waste residue is an urgent problem to be solved. At present, the main methods for the harmless and resourceful treatment of arsenic-containing waste residues are: solidification landfill, conversion to arsenic trioxide, conversion to elemental arsenic, and direct recycling. [0003] A...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B7/00C22B30/04C01G28/00C01B17/74
CPCC01B17/74C01G28/005C01P2006/80C22B7/007C22B30/04Y02P10/20Y02P20/54
Inventor 田森林张月超李英杰黄建洪胡学伟宁平谷俊杰关清卿
Owner KUNMING UNIV OF SCI & TECH