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A method for fixing arsenic by stabilizing arsenic-alkali slag to prepare scorodite

A technology for stabilization treatment and arsenic-alkali slag, which is applied in chemical instruments and methods, iron compounds, inorganic chemistry, etc., can solve the problems of secondary pollution costs, etc., and achieve stable and safe treatment, simple treatment process, and high uniformity Effect

Active Publication Date: 2021-06-01
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] Aiming at the disadvantages of secondary pollution and high cost in the processing of arsenic-alkali slag in the prior art, the purpose of the present invention is to provide an arsenic-fixing method for stabilizing arsenic-alkali slag to prepare scorodite, by which arsenic-alkali slag is processed Scorodite crystals with good crystallinity were obtained from the slag, and the arsenic leaching concentration was lower than 5mg / L, which can be stored safely for a long time

Method used

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  • A method for fixing arsenic by stabilizing arsenic-alkali slag to prepare scorodite
  • A method for fixing arsenic by stabilizing arsenic-alkali slag to prepare scorodite
  • A method for fixing arsenic by stabilizing arsenic-alkali slag to prepare scorodite

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Embodiment 1

[0029] Take 900g of arsenic-alkali slag, the liquid-solid ratio L / S is 4:1, the leaching temperature is 85°C and the leaching time is 45min as the leaching conditions, and an excess of 30% H 2 o 2 The solution is oxidized. After the reaction, solid-liquid separation is carried out, and the antimony-containing precipitate is returned to the antimony smelting system; the leachate is concentrated by half, and CO 2 to pH 8.0. Add concentrated sulfuric acid to the leaching solution gained by filtration to remove remaining alkali, leave standstill, filter to obtain the required arsenic-rich solution, analyze the concentration of As in the solution with inductively coupled plasma optical emission spectrometer (ICP-OES) to be 16.5g / L;

[0030] Measure 30mL of the above-mentioned arsenic-rich solution, and prepare FeSO 4 solution, with an appropriate amount of 30% H 2 o 2 After the solution oxidizes Fe(II), mix the iron-arsenic solution evenly, adjust the pH to 1.5, and heat to ...

Embodiment 2

[0033] Scorodite was prepared according to the method in Example 1, the initial pH value in the reaction system was controlled to be 1.8, and the rest of the reaction conditions remained unchanged, and the resulting precipitate was characterized by XRD as scorodite crystals.

[0034] Leaching toxicity test: refer to "Method 1311: ToxicityCharacteristic Leaching Procedure" promulgated by the US Environmental Protection Agency in 1992 to conduct a leaching toxicity test. The leaching concentration of As in the filtrate is determined to be 0.21mg / L, which has high environmental stability and can be stored safely. .

Embodiment 3

[0036] Scorodite was prepared according to the method of Example 1, the molar ratio of Fe / As in the reaction system was controlled to be 2.0, and the rest of the reaction conditions remained unchanged, and the obtained precipitate was characterized as scorodite crystal by XRD.

[0037] Leaching toxicity test: refer to the "Method 1311: ToxicityCharacteristic Leaching Procedure" promulgated by the US Environmental Protection Agency in 1992 to conduct a leaching toxicity test. The leaching concentration of As in the filtrate was determined to be 0.53mg / L, which has high environmental stability and can be stored safely. .

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Abstract

The invention discloses an arsenic-fixing method for preparing scorodite by stabilizing the arsenic-alkali slag, which comprises the following steps: 1) oxidatively leaching the arsenic-alkali slag, and filtering to obtain a leaching solution containing sodium carbonate and sodium arsenate and sodium antimonate Precipitation; the leaching solution is concentrated and passed into CO 2 Dealkalization, filtering to obtain dealkalization leaching solution and sodium bicarbonate crystals; 2) adding acid to the dealkalization leaching solution obtained in step 1) to control its pH to 1.0-2.5 to obtain an arsenic-rich solution; 3) according to the iron-arsenic molar ratio of 1.0-3.0 To the arsenic solution obtained in step 2) add ferrous salt and H 2 o 2 Control the pH of the mixed solution to 1.2-2.0, and react at 75-95°C to obtain scorodite crystals. The present invention treats the arsenic-alkali slag to obtain scorodite crystals with biconical octahedral morphology and uniform particles, and the arsenic leaching concentration is lower than the provisions of GB5085.3-2007 "Identification Standards for Hazardous Wastes-Leach Toxicity Identification" and can be stored safely for a long time .

Description

technical field [0001] The invention belongs to the technical field of hazardous solid waste treatment, and in particular relates to an arsenic fixation method for preparing scorodite by stabilizing arsenic-alkali slag. Background technique [0002] In antimony smelting, the crude antimony is usually refined by the alkaline refining method, that is, the method of adding alkali and blasting, to obtain refined antimony and a by-product of alkaline slag with a high arsenic content, namely, arsenic-alkali slag. At present, the total stockpile of domestic arsenic-alkali slag has reached 200,000 tons, and it is still increasing at a rate of 5,000 to 10,000 tons per year. Arsenic-alkali slag contains sodium arsenate, a soluble and highly toxic arsenic-containing compound. Once leaked, it will easily cause water pollution, soil pollution and farmland pollution. If it is not disposed of properly, arsenic in the environment may enter the human body through the enrichment of the food c...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01G49/00C01D7/00
Inventor 张寿春张楠郑雅杰龙华
Owner CENT SOUTH UNIV
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