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Concentration method of arsenic in arsenic-containing wastewater

A waste water and arsenic precipitation technology, applied in chemical instruments and methods, water pollutants, multi-stage water treatment, etc., can solve problems such as unstable arsenic-containing waste residue, high arsenic concentration requirements, unstable arsenic sulfide residue, etc.

Inactive Publication Date: 2017-09-05
SHENYANG INST OF APPLIED ECOLOGY - CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Among them, the arsenic sulfide slag produced by the arsenic sulfide precipitation process is extremely unstable; the iron-arsenic co-precipitation method will produce a large amount of unstable arsenic-containing waste slag due to its high iron-arsenic molar ratio (≥4:1); crystallization-arsenic acid The iron-arsenate molar ratio in the iron-precipitation method is about 1:1. Compared with the iron-arsenate co-precipitation method, the crystallization-iron arsenate precipitation process produces a small amount of arsenic-containing waste residue and has high stability, but the crystalline iron arsenate Precursor solution has high requirements on arsenic concentration, and low-arsenic wastewater cannot directly precipitate and crystallize-ferric arsenate

Method used

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  • Concentration method of arsenic in arsenic-containing wastewater
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Examples

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Effect test

Embodiment 1

[0046] Arsenic-containing wastewater, which contains sulfuric acid 50g / L, As(III): 1.5g / L, at room temperature, use a peristaltic pump to drive into calcium oxide and neutralize the sulfuric acid in it, and separate and remove calcium sulfate precipitation through solid-liquid separation, using a peristaltic pump Add H dropwise to wastewater 2 o 2 , control H 2 o 2 The molar ratio to trivalent arsenic is 1.2. After the oxidation reaction for 1 hour, adjust the pH of the wastewater to 5.0 with calcium oxide, and use a peristaltic pump to add ferrous chloride solution to the arsenic-containing wastewater to control the molar ratio of Fe(II) / As After the dropwise addition, continue to react for 30 minutes, control the pH of the whole reaction process to be 5.0, and obtain a mixed system; separate the solid and liquid of the mixed system to obtain a solid product and a filtrate; return the solid product to a concentrated sulfuric acid solution to control The volume and the mass...

Embodiment 2

[0050] Arsenic-containing wastewater, which contains sulfuric acid 50g / L, As(III): 6.5g / L, at room temperature, use a peristaltic pump to inject calcium oxide and neutralize the sulfuric acid in it, and separate and remove the calcium sulfate precipitate through solid-liquid separation, using a peristaltic pump Add H dropwise to wastewater 2 o 2 , control H 2 o 2 The molar ratio to trivalent arsenic is 1.5. After the oxidation reaction for 1 hour, adjust the pH of the wastewater to 5.5 with calcium oxide, and use a peristaltic pump to feed the ferrous nitrate solution in the arsenic-containing wastewater to control the molar ratio of Fe(II) / As to 1.7. , after the dropwise addition, continue to react for 30 minutes, control the pH of the whole reaction process to be 5.5, and obtain a mixed system; separate the solid and liquid of the mixed system to obtain a solid product and a filtrate; return the solid product to a concentrated sulfuric acid solution to control the volume o...

Embodiment 3

[0053] Arsenic-containing wastewater, which contains sulfuric acid 45g / L, As(III): 20mg / L, at room temperature, use a peristaltic pump to drive into calcium oxide to neutralize the sulfuric acid in it, separate and remove calcium sulfate precipitation through solid-liquid separation, and pour into the remaining liquid Feed oxygen into the phase, control the mol ratio of oxygen and trivalent arsenic to be 1.5, after oxidation reaction 2h, adjust the pH of waste water with sodium hydroxide to be 7, use peristaltic pump to ferrous sulfate solution in the waste water containing arsenic, control Fe( II) The molar ratio of As / As is 3.0:1. After the dropwise addition, continue to react for 1h, control the pH of the whole reaction process to be 6, and obtain a mixed system; separate the solid and liquid of the mixed system to obtain a solid product and a filtrate; Redissolve with concentrated hydrochloric acid solution, control the mass ratio of hydrochloric acid volume and solid produ...

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Abstract

The invention provides a concentration method of arsenic in arsenic-containing wastewater. The concentration method comprises the following steps: mixing the arsenic-containing wastewater with divalent ferric salt for precipitating the arsenic to obtain a mixed system, wherein the pH value of the precipitated arsenic is 2 to 7; performing solid-liquid separation on the mixed system to obtain a solid product; adding an acid into the solid product for dissolving. By adopting the concentration method provided by the invention, the arsenic-containing wastewater is reacted with the divalent ferric salt under the condition of the proper pH value, the arsenic is precipitated in the form of ferrous arsenate or ferrous arsenite, and the acid is added into the ferrous arsenate or the ferrous arsenite for re-dissolving, so that the arsenic is enriched and concentrated, and a high-concentration arsenic-containing solution is obtained. As proved by embodiments, by adopting the concentration method provided by the invention, the high-concentration arsenic-containing solution can be obtained, the arsenic content of the arsenic-containing solution can be adjusted easily, and further stabilization treatment on arsenic-containing waste liquid is facilitated.

Description

technical field [0001] The invention relates to the technical field of wastewater treatment, in particular to a method for concentrating arsenic in arsenic-containing wastewater. Background technique [0002] Arsenic is a toxic element that mainly exists in the form of sulfide and is associated with other metals such as: gold, copper, lead, nickel, cobalt, zinc, etc. A large amount of high (low) arsenic wastewater will be produced. The arsenic in these arsenic-containing wastewater must be removed with a stable compound. Therefore, the removal and fixation technology of arsenic in the field of non-ferrous metal smelting research projects has always been a research hotspot. [0003] At present, the commonly used treatment technologies for arsenic-containing wastewater in my country include arsenic sulfide precipitation process, iron-arsenic co-precipitation process and crystallization-iron arsenate precipitation process. Among them, the arsenic sulfide slag produced by the ...

Claims

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Application Information

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IPC IPC(8): C02F1/58C02F9/04C02F101/10
CPCC02F1/58C02F1/66C02F1/722C02F1/727C02F1/78C02F9/00C02F2101/103C02F2301/08
Inventor 贾永锋马旭
Owner SHENYANG INST OF APPLIED ECOLOGY - CHINESE ACAD OF SCI
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