Arsenic-containing wastewater treatment method

A treatment method and technology for wastewater, applied in water/sewage treatment, heating water/sewage treatment, illumination water/sewage treatment, etc., can solve the problem of high residual arsenic content increasing the amount of arsenic-containing hazardous waste, low production efficiency, and low leaching toxicity and other problems, to achieve the effect of reducing the consumption of iron salts, reducing the cost, and reducing the amount of arsenic-containing slag.

Active Publication Date: 2021-06-25
HUNAN RES INST FOR NONFERROUS METALS
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Problems solved by technology

Scoorite has the advantages of high arsenic content (up to 32%), less iron requirement, low leaching toxicity, high stability, small volume, and low storage cost, and is an arsenic-containing carrier suitable for stockpiling; current conventional preparation The scorodite methods include normal pressure method, hydrothermal method and improved normal pressure method, but the conventional preparation method of scorodite has a processing time of up to 8-12 hours, low production efficiency, and the amount of residual arsenic in the treated wastewater is as high as 300-500mL / L, because iron salt with high iron-to-arsenic ratio needs to be added in the subsequent deep arsenic removal, so the high residual arsenic amount increases the amount of hazardous arsenic waste in the conventional scorodite method

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  • Arsenic-containing wastewater treatment method

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Embodiment 1

[0028] A method for treating arsenic-containing wastewater of the present invention, the schematic diagram of its technological process is as follows figure 1 As shown, the treated arsenic-containing wastewater is the mixed wastewater (arsenic content is 8.9g / L) of an antimony smelter's arsenic-alkali slag leaching solution and acid sewage, which specifically includes the following steps:

[0029] (1) Add 2 mL of hydrogen peroxide to 220 mL of arsenic-containing wastewater, stir and react for 60 minutes, filter after the reaction, remove the filter residue, and enter the filtrate for subsequent treatment;

[0030] (2) Add the filtrate after step (1) into the microwave reactor, start the microwave, the microwave frequency is 2450MHz, heat up to 85°C, and slowly mix the iron and arsenic molar ratio of 1.25:1 under the stirring speed of 200r / min. Add 30mL of ferric sulfate solution dropwise at a rate of 0.5mL / min, and carry out the arsenic precipitation reaction under the conditi...

Embodiment 2

[0034] A method for treating arsenic-containing wastewater of the present invention, the processed arsenic-containing wastewater is the acid sewage of a certain lead-zinc smelter (its main chemical composition is as shown in Table 1), specifically comprising the following steps:

[0035] Main constituent elements and content of arsenic-containing wastewater in Table 1 Example 2

[0036] element As Cd Pb Cu Zn content 2.17g / L 145mg / L 18mg / L 0.16mg / L 0.56mg / L

[0037] (1) Add 1 mL of hydrogen peroxide to 100 mL of arsenic-containing wastewater, stir and react for 60 minutes, filter after the reaction, remove the filter residue, and enter the filtrate for subsequent processing;

[0038] (2) Put the filtrate after step (1) into the microwave reactor, start the microwave, the microwave power is 2450MHz, heat up to 85°C, at the stirring speed of 200r / min, the molar ratio of iron to arsenic is 1.2:1 and slowly Add 30mL of ferric sulfate solutio...

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Abstract

The invention provides an arsenic-containing wastewater treatment method which comprises the following steps: adding an oxidizing agent into arsenic-containing wastewater, stirring for reaction, filtering after the reaction is completed, removing filter residues, and carrying out subsequent treatment on filtrate, pouring the filtrate into a microwave reactor, starting microwaves, heating, then slowly dropwise adding ferric salt, carrying out an arsenic precipitation reaction under the condition that the pH value is 2-3, carrying out heat preservation and aging after the reaction is completed, and then filtering to obtain a low-arsenic wastewater solution and filter residues which are scorodite; and firstly adding a neutralizer into a low-arsenic wastewater solution to adjust the pH value, then adding ferric salt to deeply remove residual arsenic in the low-arsenic wastewater, and filtering to obtain filtrate, namely arsenic-removed wastewater. According to the treatment method disclosed by the invention, the arsenic-containing wastewater is treated by microwave assistance, so that the wastewater treatment efficiency is effectively improved, the consumption of ferric salt in the subsequent deep arsenic removal process is effectively reduced, and the hazardous waste amount is reduced and the cost is further reduced.

Description

technical field [0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a treatment method for arsenic-containing wastewater. Background technique [0002] Arsenic is the main associated element in copper, lead, zinc, tin, antimony and other non-ferrous and precious metal ores, and it will enter into the smoke and waste acid to varying degrees during the extraction of non-ferrous metals. Except for a very small amount of arsenic recovered in the form of arsenic trioxide, most of the arsenic is discharged into the environment in the form of arsenic-containing solid waste after being removed from the waste liquid. [0003] At present, domestic and foreign methods for treating arsenic-containing wastewater mainly include lime method, lime iron salt method, sulfidation method, pyrolusite method, scorodite method, iron oxide coated sand treatment and other methods. The ideal treatment method should reduce the cost of treatment, r...

Claims

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Application Information

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IPC IPC(8): C02F9/10C02F1/62C02F1/30C02F1/72C02F1/02C02F1/66C02F101/20
CPCC02F9/00C02F1/62C02F1/302C02F1/72C02F1/722C02F1/74C02F1/02C02F1/66C02F2101/20Y02P10/20
Inventor 曹柏林万文玉欧阳坤陈佳利彭新平
Owner HUNAN RES INST FOR NONFERROUS METALS
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