Method for treating arsenic-containing wastewater and solidifying arsenic

A wastewater treatment and wastewater technology, which is applied in water/sewage treatment, chemical instruments and methods, and neutralized water/sewage treatment, etc., can solve the problems of high requirements for bacterial culture, long arsenic-fixing operation cycle for microorganisms, and low efficiency, etc. To achieve the effect of shortened reaction time, stable structure and reduced cost

Active Publication Date: 2020-05-19
宁波弗镁瑞环保科技有限公司 +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method is economically feasible, but requires high strain culture, and the microbial arsenic fixation cycle is long and the efficiency is low

Method used

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  • Method for treating arsenic-containing wastewater and solidifying arsenic
  • Method for treating arsenic-containing wastewater and solidifying arsenic
  • Method for treating arsenic-containing wastewater and solidifying arsenic

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] Take smelting flue gas to wash arsenic-containing wastewater 5m 3 , stir and add calcium iodide, I in the solution - The ion concentration is 0.002mg / L, with H 2 SO 3 As reducing agent, use I - Use ions as a catalyst to reduce As(V) to As(III). After reacting at room temperature for 0.5 h, add limestone powder to adjust the pH of the solution to 2.7, and filter to obtain a calcium sulfate filter cake containing 0.03% As and a deacidified liquid; Stir the resulting deacidification liquid into milk of lime, adjust the pH to 8.1, stir at room temperature for 1 hour, filter and separate the heavy metal precipitate, continue to add milk of lime, adjust the pH to 12, and stir at room temperature for 0.5 hour to precipitate the arsenic in it, and filter to obtain As content of 35.87% arsenic-calcium precipitation slag and precipitated liquid, the precipitated liquid is directly returned to the smelting flue gas washing process for recycling. The obtained arsenic-calcium pr...

Embodiment 2

[0056] Take the smelting flue gas to wash the arsenic-containing wastewater 3m 3 , stir and add limestone powder, adjust the pH of the solution to 2.5, filter to obtain a calcium sulfate filter cake containing 0.1% As and the neutralized liquid, stir the obtained neutralized liquid, add lime milk, adjust the pH to 12.5, and stir at room temperature for 1.5h. The arsenic and heavy metals in it are precipitated together, and the mixed sedimentation residue and the precipitated liquid are obtained by filtration, and the precipitated liquid is returned to the reclaimed water for reuse. The obtained mixed sediment residue was slurried in a pressure reactor by adding water at a solid-to-liquid ratio of 1:2 g / mL, and adjusting the pH to 4.5 with dilute sulfuric acid, adding ferrous sulfate at a molar ratio of arsenic / iron of 1:1.2, and pressing the As( III) Oxidation to As(V) and Fe(II) to Fe(III) is 1.5 times the theoretical amount required to oxidize to Fe(III) Add hydrogen peroxid...

Embodiment 3

[0060] Take 3L of sodium arsenate solution with an As concentration of 35.8g / L obtained from the copper electrolyte indirect self-purification load accelerator regeneration process, stir and add lime at 95°C for causticization, filter to obtain calcium arsenate-containing precipitate residue and arsenic-removed liquid, After dearsenicization, the liquid is returned to continue to be used as a regeneration liquid for loading accelerators. The precipitated residue containing calcium arsenate is slurried by adding water at a solid-to-liquid ratio of 1:2g / mL, and the pH is adjusted to 2.5 by adding sulfuric acid. :1.15 Add ferric sulfate, stir to make the arsenic in it convert into amorphous iron arsenate precipitation, filter to obtain filter residue and filtrate, and the filtrate returns to continue to be used as the transformation liquid of calcium arsenate precipitate residue, and the filter residue is 1:2g according to the solid-liquid ratio / mL was added to the sodium bisulfa...

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Abstract

The invention discloses a method for treating arsenic-containing wastewater and solidifying arsenic. The method comprises the following steps: separating and enriching arsenic in the arsenic-containing wastewater in the form of calcium arsenate or/and calcium arsenite precipitate; and oxidizing the obtained arsenic enriched product in a ferric sulfate or ferrous sulfate solution, and carrying outnormal-pressure reaction or pressurized hydrothermal reaction or normal-pressure hydrothermal reaction, so that arsenic in the arsenic enriched product is solidified in the form of scorodite crystals.The obtained scorodite crystals are complete in grain development, uniform in grain distribution and stable in structure under acidic conditions. The method has the advantages of high operation efficiency, good arsenic fixation effect, convenience in operation, low arsenic solidification treatment cost and the like, and is suitable for industrial application of harmless treatment of arsenic-containing wastewater.

Description

technical field [0001] The invention belongs to the field of environmental protection, and in particular relates to a method for treating arsenic-containing wastewater and solidifying arsenic. Background technique [0002] Arsenic is a toxic and harmful element, and the direct discharge of arsenic-containing wastewater will pollute the environment. Therefore, it is necessary to treat arsenic-containing wastewater. At present, the treatment methods of arsenic-containing wastewater mainly include: neutralization precipitation method, coagulation precipitation method, pyrolusite method, sulfide precipitation method, and scorodite method. [0003] The neutralization precipitation method is to add lime or limestone to the arsenic-containing wastewater, so that the arsenic in the solution is precipitated in the form of calcium arsenate or / and calcium arsenite, and the calcium-arsenic slag and the precipitated liquid are obtained by filtration. The method has the advantages of si...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C02F101/10
CPCC02F9/00C02F2101/103C02F1/66C02F1/70C02F1/001C02F2001/007C02F1/5236C02F1/705C02F1/72C02F1/78C02F1/722C02F1/76
Inventor 王学文孟钰麒王懿刘湘雄王明玉
Owner 宁波弗镁瑞环保科技有限公司
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