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Arsenic fixing method for preparing scorodite through stabilization treatment of arsenic-alkali residue

A technology for stabilization treatment and arsenic-alkali slag, applied in chemical instruments and methods, inorganic chemistry, iron compounds, etc., can solve the problems of secondary pollution costs, etc., and achieve the effect of simple and energy-saving equipment, simple reaction operation, and high uniformity

Active Publication Date: 2019-05-28
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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  • Arsenic fixing method for preparing scorodite through stabilization treatment of arsenic-alkali residue
  • Arsenic fixing method for preparing scorodite through stabilization treatment of arsenic-alkali residue
  • Arsenic fixing method for preparing scorodite through stabilization treatment of arsenic-alkali residue

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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 through stabilization treatment of arsenic-alkali residue. The arsenic fixing method comprises the following steps: (1) the arsenic-alkali residue is subjected to oxidation leaching, filtering is conducted to obtain leachate containing sodium carbonate and sodium arsenate, and sodium antimonite precipitation, after the leachate is concentrated, CO2 is introduced for dealkalization, and filtering is conducted to obtain dealkalized leachate and sodium bicarbonate crystals; (2) acid is added into the dealkalized leachate obtained in the step (1) to control the pH of the dealkalized leachate to be 1.0-2.5, and an arsenic-rich solution is obtained; and (3) a mixed solution of ferrous salt and H2O2 is added into the arsenic-rich solution obtained in the step (2) according to the iron-arsenic molar ratio of 1.0-3.0, the pH of the mixture is controlled to be 1.2-2.0, the mixture reacts at 75-95 DEG C, and scorodite crystals are obtained. The arsenic-alkali residue is treated to obtain the scorodite crystals with the double-cone octahedron shape and uniform particles, the arsenic leaching concentration is lower than the concentration stipulated by the GB5085.3-2007 'hazardous waste identification standard-leaching toxicity identification', and the scorodite crystals can be safely stored for a long term.

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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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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