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Method for converting arsenic residue into scorodite in one step

A technology of scorodite and transformation, applied in chemical instruments and methods, inorganic chemistry, iron compounds, etc., can solve the problems of polluting the atmospheric environment, explosion, complex process, etc., and achieve the effects of easy precipitation, large particles, and simple operation.

Inactive Publication Date: 2020-04-21
FUZHOU UNIVERSITY
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The above-mentioned methods for generating scorodite involve the leaching-oxidation-reprecipitation steps of arsenic slag, so the process is relatively complicated
[0004] In order to simplify the treatment process, some studies have improved the treatment process of arsenic slag from arsenic slag leaching-reprecipitation (two-step method) to directly transforming arsenic slag into scorodite (one-step method). For example, Zhang Weifang et al. After the solution containing iron ions and nitrate ions is mixed, hydrothermal treatment is carried out, and finally the arsenic sulfide slag is converted into stable scorodite (a method for one-step detoxification and sulfur recovery of arsenic sulfide slag)[Z].CN110240112A), but this After the method is processed, a large amount of nitrogen monoxide and nitrogen dioxide toxic gases will be produced, seriously polluting the atmospheric environment, and the generation of gas has a certain explosion risk for the hydrothermal process; in addition, this method is only applicable to the treatment of arsenic sulfide slag

Method used

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  • Method for converting arsenic residue into scorodite in one step
  • Method for converting arsenic residue into scorodite in one step
  • Method for converting arsenic residue into scorodite in one step

Examples

Experimental program
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Effect test

Embodiment 1

[0030] Take 0.1 g of arsenic sulfide slag in a reaction kettle, add 10 mL of 10wt% hydrogen peroxide, and 5 mL of 0.08 mol / L ferric sulfate solution, so that the solid-liquid ratio is 1:150 g / ml, and adjust the pH to 2 with sulfuric acid After stirring evenly, the reaction kettle was put into 100°C, 120°C, 140°C, and 160°C for 10 h, and cooled to room temperature naturally. Through cleaning and flotation, the yellow agglomerated sulfur element and the gray-green scorodite solid are finally separated, and the scorodite particle size increases with the increase of temperature, and the stability improves. Toxic leaching experiments showed that the toxic leaching of arsenic was less than 1.2 mg / L.

Embodiment 2

[0032] Take 0.1 g of arsenic sulfide slag in the reaction kettle, add 10 mL of 10wt% hydrogen peroxide, and 5 mL of 0.08~0.16 mol / L (Fe / As=1~2) ferric sulfate solution, so that the solid-liquid ratio is 1: 150 g / ml, using sulfuric acid to adjust pH = 2, after stirring evenly, put the reaction kettle at 160°C for 10 h, and let it cool down to room temperature naturally. Through cleaning and flotation, yellow agglomerated sulfur element and gray-green scorodite solid were finally separated. As the iron concentration increases, the arsenic fixation rate increases from 82% to 92%, and the particle size becomes smaller. When the molar ratio of iron to arsenic reaches 1.6:1, the product is a mixed phase of scorodite and iron oxide. The toxic leaching of arsenic in scorodite produced under these conditions was less than 1.5 mg / L.

Embodiment 3

[0034]Take 0.1 g of arsenic sulfide slag in a reaction kettle, add 10 mL of 10 wt% hydrogen peroxide, and 5 mL of 0.1 mol / L ferric sulfate solution, so that the solid-liquid ratio is 1:150 g / ml, and adjust the pH with sulfuric acid 1, 2 or 3. After stirring evenly, put the reaction kettle at 160°C for 10 h, and let it cool down to room temperature naturally. Through cleaning and flotation, yellow agglomerated sulfur element and gray-green scorodite solid were finally separated. The experimental results show that the arsenic in the arsenic sulfide slag can be fixed within the pH range of 1-3, and when the pH value is 2, the arsenic fixation rate can reach 91%, and the leaching toxicity concentration of arsenic is less than 1.0 mg / L.

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Abstract

The invention discloses a method for one-step conversion of arsenic residue into scorodite. According to the method, mainly a hydrothermal method is used; a ferric sulfate solution is introduced as amineralizer, arsenic residue is rapidly converted into large-particle-size scorodite in a certain oxidation environment, the conversion conditions are optimized, and the stability of the scorodite isevaluated; the determined optimal experiment conditions are that the temperature is 160 DEG C, the pH is 2, a molar ratio of Fe to As is 1.2:1, and the hydrothermal time is 6 hours; the obtained hydrothermal product is grey green scorodite, the particle size of the scorodite is 10-30 [mu]m, the toxicity leaching concentration of arsenic is smaller than 2 mg / L, and the stipulation of solid waste identification standard-leaching toxicity identification (GB5085.3-2007) is met; and if the arsenic residue is arsenic sulfide residue, the method can stabilize the arsenic residue and recover elementalsulfur at the same time, so that the technology is economical and effective for stabilizing treatment of the arsenic residue.

Description

technical field [0001] The invention belongs to the field of nonferrous metal smelting technology and environmental protection, and specifically relates to a method for converting arsenic slag into scorodite in one step. Background technique [0002] Arsenic often coexists in minerals containing precious metals or non-ferrous metals. Therefore, in the process of metal smelting, ore dressing, and sulfuric acid preparation, a large amount of acidic and high-concentration arsenic-containing wastewater will be produced. The treatment of this arsenic-containing wastewater mainly adopts the precipitation process, but a large amount of arsenic-containing waste residues such as calcium arsenate slag, iron arsenate slag, arsenic sulfide slag, etc. will be produced during the treatment process. And the processing effect is good, so this method is widely used. Arsenic slag is hazardous waste, easy to cause cancer, and most of these arsenic slags are in an amorphous state, so they are ...

Claims

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Application Information

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IPC IPC(8): C01G49/00
CPCC01G49/00C01P2002/72C01P2004/03C01P2004/61
Inventor 王永好李明洋王永净连进禄时坚
Owner FUZHOU UNIVERSITY
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