Method for recycling arsenic-containing waste residues

A recycling and waste slag technology, applied in the field of hazardous waste resource utilization, can solve problems such as complex resource utilization process and difficult disposal of arsenic-containing waste residue, achieve significant economic and environmental benefits, alleviate random stacking, and facilitate operation Effect

Active Publication Date: 2011-01-26
TONGJI UNIV
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  • Abstract
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Problems solved by technology

[0005] Therefore, the present invention aims at the problems of difficult treatment and disposal of arsenic-containing waste slag at the present stage and complicated resource utilization process, and develops a method for recycling arsenic-containing waste slag by combining alkali leaching and pickling methods, aiming at exploring a new path of As(III) -As(III) arsenic-containing waste slag recycling process

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  • Method for recycling arsenic-containing waste residues
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Examples

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Effect test

Embodiment 1

[0031] The object of treatment is arsenic-containing tailings slag from a chemical plant. The slag is in the form of yellow mud, and the arsenic content in the slag is 288.8 mg / kg. X-ray diffractometer (XRD) detection shows that the arsenic in the arsenic-containing tailings slag is mainly composed of As 2 S 3 and As 2 o 3 form exists. The separation and preparation of arsenic trioxide from the arsenic-containing waste residue specifically includes the following steps:

[0032] (1) Add NaOH and arsenic-containing tailings slag with a mass ratio of 0.6 into the tank reactor, add water to mix as an alkaline leaching medium, control the mass ratio of water to NaOH and arsenic-containing tailings slag mixed solids to be 5, and adjust the stirring speed to 200r / min, mechanically stirred at room temperature for 30min, filtered to obtain alkali leaching solution and alkali leaching residue.

[0033](2) For the alkaline immersion solution obtained in step (1), add concentrated su...

Embodiment 2

[0038] The processing object is the same as that in Embodiment 1.

[0039] (1) Control the mass ratio of KOH and arsenic-containing tailings slag to 1.4, add water as the alkali leaching medium for mixing and stirring, and control the liquid-solid ratio of the alkali leaching medium and KOH and arsenic-containing tailings slag mixed solid to 3, stirring speed 200r / min, stirring time 60min , filtered, and filtered to obtain alkali leaching solution and alkali leaching residue.

[0040] (2) For the alkaline immersion solution obtained in step (1), add concentrated sulfuric acid with a volume fraction of 10% as the pickling medium, and place the mixture in an oscillator for pickling for 1 hour at a pickling temperature of 15°C and an oscillator speed of 200r / min , the oscillation is over, centrifuged, filtered to obtain pickling solution and pickling precipitate.

[0041] (3) The pickling precipitate in step (2) is washed twice with 1% dilute sulfuric acid by volume fraction, an...

Embodiment 3

[0045] The treatment object was the same as in Example 1, and the alkaline leaching medium used was the arsenic-containing alkaline leaching solution produced by leaching the arsenic-containing waste residue with NaOH solid alkali, wherein the As concentration was 38.4g / L, the pH was 11.47, and the COD was 3.62mg / L.

[0046] (1) Control the mass ratio of NaOH and arsenic-containing tailings slag to 1.0, add arsenic-containing alkali leaching solution as the alkali leaching medium for mixing and stirring, control the liquid-solid ratio of the alkali leaching medium and NaOH and arsenic-containing tailings slag mixed solid to 10, and stir at a speed of 200r / min, stirring time 180min, filtered to obtain alkali leaching solution and alkali leaching residue.

[0047] (2) For the alkaline immersion solution obtained in step (1), add concentrated sulfuric acid with a volume fraction of 10% as the pickling medium, and place the mixture in an oscillator for pickling for 2 hours at a pi...

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Abstract

The invention relates to a method for recycling arsenic-containing waste residues, which comprises the two steps of the alkaline leaching of the arsenic-containing waste residues and acid-washing separation of extract. The method comprises the following specific steps of: mixing the arsenic-containing waste residues, an inorganic strong alkaline solid and an alkaline leaching medium according to a certain ratio, reacting for 10 to 180 minutes by mechanically stirring and then filtering, and performing safe landfill in the subsequent process, wherein compared with the quality of non-processed residues, the quality of filter residues is reduced by 80 to 98 percent; adding filter liquor into concentrated acid for acid washing at the temperature of between 10 and 25 DEG C for 1 to 2 hours, wherein the added amount of an acid-washing medium is 5 to 10 volume percent of the alkaline leaching solution; filtering the mixture, and after washing filter residues with 0.02 to 1 percent dilute acid, drying to obtain As2O3 powder (the purity is over 95 percent); and returning acid-washing filter liquor and dilute acid washing liquor to the alkaline leaching step. The method has the advantages of simple process, convenience of operation, low cost, small secondary pollution and the like, and at the present, arsenic-containing waste residues pour in the environment, the method has the obvious economic, social and environmental benefits.

Description

technical field [0001] The invention belongs to the technical field of resource utilization of hazardous waste, in particular to a method for preparing As 2 o 3 powder method. Background technique [0002] As an indicator element of rare metals, arsenic is mined in large quantities along with rare metals. my country produces about 50,000 tons of arsenic-containing waste slag annually. However, a large amount of arsenic slag has not been properly treated. At present, the amount of open-air hoarding has exceeded 300,000 tons, which has caused serious environmental problems. [0003] Solidification and stabilization treatment is a commonly used pretreatment method for heavy metal hazardous waste. Commonly used solidification and stabilization materials include cement, lime, etc. It is technically feasible to use cement solidification combined with safe landfill treatment, but the economic cost is high, which has become the main bottleneck restricting its wide application. I...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09B3/00C01G28/00
Inventor 何品晶姚倩章骅邵立明
Owner TONGJI UNIV
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