Method for removing trivalent arsenic

A technology for trivalent arsenic and pentavalent arsenic is applied in the field of pollutant treatment, which can solve the problems of difficult production, slow speed, and unsuitable for direct treatment of low-concentration arsenic-containing wastewater.

Active Publication Date: 2016-07-13
INST OF PROCESS ENG CHINESE ACAD OF SCI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the rate of oxidation of trivalent arsenic in water to pentavalent arsenic under acidic conditions is very slow, so scorodite can only be produced by pressurized oxidation in the existing industrial process, which requires high equipment investment and great difficulty in production. GordonM. Ritcey. mentioned in the article (Tailingsmanagementingoldplants.Hydrometallurgy, 2005, 78, 3–20) that the scorodite arsenic fixation method is only applied in a few gold smelting enterprises that adopt the pressure leaching process route
G.P.Demopoulos et al. from McGill University in Canada pro

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  • Method for removing trivalent arsenic

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Embodiment 1

[0052] A method for removing trivalent arsenic in arsenic-containing drainage of a simulated mine, wherein the arsenic-containing drainage of the simulated mine is passed through sodium arsenite (Na 3 AsO 3 ) and iron sulfate (Fe 2 (SO 4 ) 3 ) is dissolved in water and prepared, wherein the concentration of trivalent arsenic is 300mg / L, and the concentration of iron is 1g / L. The method comprises the following steps:

[0053] (1) Take 1000 ml of arsenic-containing drainage from the simulated mine, adjust the pH to 1.0 with sulfuric acid, and pass in ozone-containing gas (concentration about 40 mg / L) generated by the ozone generator at 20 ° C, stir and ventilate for 10-40 minutes After that, a solution containing pentavalent arsenic is obtained;

[0054] (2) Add 5g ferrous sulfate heptahydrate (FeSO4) to the solution containing pentavalent arsenic 4 ·7H 2 0), after stirring and dissolving, the temperature is raised to 70° C. and the air is reacted. During the reaction, sul...

Embodiment 2

[0057] A method for removing trivalent arsenic in arsenic-gold concentrate bioleaching waste liquid, said arsenic-containing gold concentrate bioleaching waste liquid contains 2.8g / L arsenic, 3.6g / L iron, and an initial pH of 2.2. The method includes the following steps:

[0058] (1) Take 1000 milliliters of arsenic-containing gold concentrate bioleaching waste liquid, adjust the pH to 1.3 with sulfuric acid, and feed the ozone-containing gas (concentration of about 40 mg / L) produced by the ozone generator at 25 ° C, and stir and ventilate After 10-40 minutes, a solution containing pentavalent arsenic was obtained;

[0059] (2) Add 10g ferrous sulfate heptahydrate (FeSO4) to the solution containing pentavalent arsenic 4 ·7H 2 0), after stirring and dissolving, the temperature is raised to 70° C. and the air is reacted. During the reaction, sulfuric acid and sodium hydroxide are added to control the pH between 0.9-1.5. After 3 hours of reaction, the crystal precipitate contai...

Embodiment 3

[0062] A method for removing trivalent arsenic in arsenic-containing wastewater produced by zinc smelting, wherein the arsenic-containing wastewater produced by zinc smelting contains 0.5 g / L of arsenic, 1.0 g / L of iron, and an initial pH of 2.2.

[0063] (1) Take 1000 milliliters of arsenic-containing waste water produced by zinc smelting, adjust the pH to 1.3 with sulfuric acid, and feed the ozone-containing gas (concentration about 40 mg / L) produced by the ozone generator at 15°C, stir, and ventilate for 10- After 40 minutes, a solution containing pentavalent arsenic was obtained;

[0064] (2) Add 5g ferrous sulfate heptahydrate (FeSO4) to the solution containing pentavalent arsenic 4 ·7H 2 0), after stirring and dissolving, the temperature is raised to 70° C. and the air is reacted. During the reaction, sulfuric acid and sodium hydroxide are added to control the pH between 0.9-1.5. After 3 hours of reaction, the crystal precipitate containing scorodite and goethite precip...

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Abstract

The invention provides a method for removing trivalent arsenic, comprising the following steps: (1), oxidizing trivalent arsenic in an arsenic solution into pentavalent arsenic at pH of 0.9-1.5 by using ozone to obtain pentavalent arsenic solution; (2), adding a soluble divalent iron source into the pentavalent arsenic solution, oxidizing divalent iron at a temperature higher than 70 DEG C at pH less than 1.5 into trivalent iron, and reacting the pentavalent arsenic with trivalent iron to obtain a solution containing scorodite crystal precipitate, goethite precipitate and divalent iron; (3), adjusting pH of the solution obtained in step (2), oxidizing the divalent iron in the solution to form iron peroxide gel, and carrying out solid-liquid separation to obtain a purified solution.The method enables low-concentration arsenic in waste water to be removed, arsenic content of the purified solution is lower than 0.05 mg/L, the precipitates generated in the arsenic removal process are easy to remove, and the method is simple to perform and is widely applicable to purifying waste water containing low-concentration arsenic.

Description

technical field [0001] The invention belongs to the technical field of pollutant treatment, and relates to a method for removing trivalent arsenic, in particular to a method for removing trivalent arsenic in a solution by using ozone. Background technique [0002] Arsenic is a highly toxic element, and a small amount of ingestion can cause death. Chronic arsenic poisoning can cause cancer and other diseases. On the other hand, arsenic is a relatively abundant element in nature, and it is one of the 20 most abundant elements in the earth's crust, and there are more than 200 arsenic-containing minerals. Mine development and natural weathering can lead to the dissolution of arsenic-containing minerals, resulting in arsenic-containing wastewater, resulting in large-scale arsenic pollution. Such arsenic-containing wastewater usually has a low arsenic concentration, ranging from tens of milligrams per liter to several grams per liter, but arsenic mainly exists in the form of high...

Claims

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Application Information

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IPC IPC(8): C02F9/04
CPCC02F1/5245C02F1/66C02F1/70C02F1/78C02F9/00
Inventor 张广积杨超李媛媛O·那桑托格托克门玉
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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