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Method for obtaining high-leaching stability scorodite by precipitating arsenic-containing solution

A scorodite, stable technology, applied in chemical instruments and methods, inorganic chemistry, iron compounds, etc., to achieve the effects of low equipment requirements, easy solid-liquid separation, and simple process

Active Publication Date: 2017-06-13
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Among the currently published patents, the invention patents (CN 102153145 A, CN101952204 A) of Dowa Mining Co., Ltd. in Japan first proposed to use divalent iron as the iron source to process the arsenic-containing solution and prepare scorodite and iron arsenate powder. Arsenic precipitation is thorough, simple and convenient, but the prepared scorodite and ferric arsenate can only be stored stably in a narrow pH range (2-6), and the toxicity of arsenic leaching under alkaline or strong reducing conditions far exceeds that of GB5085 .3-2007 national standard limits (<5mg / L)

Method used

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  • Method for obtaining high-leaching stability scorodite by precipitating arsenic-containing solution
  • Method for obtaining high-leaching stability scorodite by precipitating arsenic-containing solution
  • Method for obtaining high-leaching stability scorodite by precipitating arsenic-containing solution

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Preparation of scorodite

[0032] Take 100g of arsenic trioxide, add 200g of hydrogen peroxide solution with a mass fraction of 30%, add distilled water to 500ml, heat and boil until the solid particles are completely dissolved, then continue to boil for 2h, titrate the concentration of trivalent arsenic ions in it by titration, if There is also trivalent arsenic, then continue heating until all trivalent arsenic is oxidized to pentavalent. Add water to make up the volume until the concentration of arsenic is 30g / L, and measure it by ICP-AES, the obtained solution is 30g / L arsenic acid solution.

[0033] Take 250ml of the 30g / L arsenic acid solution prepared by the above method, adjust the pH value to 1.5 with NaOH, preheat to 90°C, and stir; add ferrous salt solution and neutralizing agent sodium carbonate solution to it at the same time to control the reaction system The molar ratio of Fe / As in the medium is 2:1, and concentrated H 2 SO 4 Adjust the pH to 1.5. Whe...

Embodiment 2

[0039] Preparation of scorodite

[0040] Scoorite was prepared according to the method of Example 1, wherein the concentration of arsenic acid was 40 g / L, and other conditions remained unchanged, and scorodite powder with good crystallization state was obtained.

[0041] toxic leaching

[0042](1) Carry out toxic leaching in accordance with GB5085.3-2007 (identification standard for solid waste—identification of leaching toxicity), the leaching concentration of arsenic is 0.15mg / L, which is less than the limit of the standard, and can be safely and stably stored;

[0043] (2) According to the liquid-solid mass ratio of 20:1, mix 1g of scorodite powder prepared above with 20ml of NaOH+CaO mixed solution with a pH value of 9.67, leaching for 40 days at 25°C, and measure the content of arsenic in it. The leaching concentration is 0.26mg / L.

Embodiment 3

[0045] Preparation of scorodite

[0046] Scoorite was prepared according to the method of Example 1, wherein the concentration of arsenic acid was 70 g / L, and other conditions remained unchanged, and scorodite powder with good crystallization state was obtained.

[0047] toxic leaching

[0048] (1) Toxic leaching is carried out according to GB5085.3-2007 (Standard for identification of solid waste - identification of leaching toxicity), the leaching concentration of arsenic is 0.20mg / L, which is less than the limit value of this standard, and it can be stored safely and stably;

[0049] (2) According to the liquid-solid mass ratio of 20:1, mix 1g of scorodite powder prepared above with 20ml of NaOH+CaO mixed solution with a pH value of 9.67, leaching for 40 days at 25°C, and measure the content of arsenic in it. The leaching concentration is 0.30mg / L.

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Abstract

The invention relates to a method for obtaining high-leaching stability scorodite by precipitating an arsenic-containing solution. The method comprises the following steps: adding a ferrite solution as an arsenic precipitating agent in a continuous feeding mode, and simultaneously adding a neutralizing agent in a certain concentration; continuously introducing oxygen for oxidizing ferrous ions into ferric ions, and then reacting with arsenic in the solution, thus generating the high-leaching stability scorodite. The obtained scorodite can be stably stacked and stored within a pH (Potential of Hydrogen) value range of 2 to 11 and under a strong reducing condition.

Description

technical field [0001] The invention belongs to the technical field of mineral arsenic fixation, and relates to an arsenic fixation method for treating arsenic-containing waste liquid produced in the metallurgical process of nonferrous metals. Background technique [0002] Arsenic is a highly toxic element with high carcinogenicity, and is widely associated in various non-ferrous metal smelting process systems. In the past 30 years, with the rapid development of my country's nonferrous metal industry, the problem of arsenic pollution has become more and more serious, seriously threatening people's lives and health. Therefore, the research on arsenic pollution control is an urgent and significant topic. [0003] At present, arsenic fixation technologies mainly include encapsulation and mineral arsenic fixation. Encapsulation is to use cement, glass and other materials to coat arsenic-containing materials so that they can be stored stably. This method has a large amount of ...

Claims

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Application Information

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IPC IPC(8): C01G49/00
CPCC01G49/00C01P2002/72C01P2004/03C01P2004/30
Inventor 刘志宏柯平超刘智勇李玉虎刘付朋李启厚王祖林
Owner CENT SOUTH UNIV
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