A method for preparing highly stable arsenic-fixed minerals by hydrothermal method

A high stability, hydrothermal technology, applied in the field of mineral arsenic fixation, to achieve the effect of wide stable area, low equipment requirements, and small BET specific surface area

Active Publication Date: 2019-08-27
CENT SOUTH UNIV
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  • Abstract
  • Description
  • Claims
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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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  • A method for preparing highly stable arsenic-fixed minerals by hydrothermal method

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Experimental program
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Effect test

Embodiment 1

[0037] The main components in the arsenic-containing solution include: As 60g / L, Sb 1.1g / L, Pb 235ppm, Sn 38.5ppm, Te24.4ppm, NaOH 30g / L.

[0038] A method for preparing high-stability solid arsenic minerals includes the following steps: the arsenic-containing solution adopts a catalytic oxidation method to 3+ Oxidized to As 5+ , The control condition is that the oxygen flow rate is 5L / min, adding KMnO 4 For the catalyst, the As / Mn molar ratio is controlled at 10:1, and the temperature of the catalytic oxidation system is controlled at 90℃. The results show that As 3+ The conversion rate is 98.45%.

[0039] Adjust the pH value of the oxidized liquid to 1.5, and add CaO and Ca(OH) by continuous feeding 2 As an arsenic precipitation agent, the molar ratio of Ca / As is 5, the settling time is 6 hours, and the reaction temperature is 60°C to generate calcium arsenate. The synthesis of arsenic-fixed minerals adopts the hydrothermal method, and the control condition is that the calcium ars...

Embodiment 2

[0041] The main components in the arsenic solution include: As 76g / L, Sb 0.8g / L, Pb 96.7ppm, Sn 27.5ppm, Te38.7ppm, NaOH 25g / L.

[0042] A method for preparing high-stability solid arsenic minerals includes the following steps: the arsenic-containing solution adopts a method of catalytic oxidation to remove As 3+ Oxidized to As 5+ , The control condition is that the oxygen flow rate is 10L / min, adding KMnO 4 For the catalyst, the As / Mn molar ratio was controlled at 40:1, and the temperature of the catalytic oxidation system was controlled at 30℃. The results showed that As 3+ The conversion rate is 92.31%;

[0043] Adjust the pH value of the oxidized liquid to 2, add CaO and Ca(OH) in a continuous feeding manner 2 As an arsenic precipitant, the molar ratio of Ca / As is 8, the settling time is 8 hours, and the reaction temperature is 90°C to generate calcium arsenate. The synthesis of solid arsenic minerals adopts the hydrothermal method, and the control condition is that calcium arse...

Embodiment 3

[0045] The main components in the arsenic solution include: As 50g / L, Sb 1.8g / L, Pb 186ppm, Sn 34.7ppm, Te27.8ppm, NaOH 5g / L.

[0046] A method for preparing high-stability solid arsenic minerals includes the following steps: the arsenic-containing solution adopts a method of catalytic oxidation to remove As 3+ Oxidized to As 5+ , The control condition is that the oxygen flow rate is 1L / min, adding KMnO 4 For the catalyst, the As / Mn molar ratio is controlled at 20:1, and the temperature of the catalytic oxidation system is controlled at 120℃. The results show that As 3+ The conversion rate is 89.36%

[0047] Adjust the pH value of the oxidized liquid to 1.5, and add CaO and Ca(OH) by continuous feeding 2 As an arsenic precipitation agent, the molar ratio of Ca / As is 5, the settling time is 10 hours, and the reaction temperature is 60°C to generate calcium arsenate. The synthesis of solid arsenic minerals adopts the hydrothermal method, and the control condition is that the calcium a...

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Abstract

The invention relates to a method for preparing high-stability solid arsenic minerals by a hydrothermal process. Arsenic is removed from a high-arsenic solution and solidified, and harmless treatment is carried out on the arsenic-containing solution. According to the method, trivalent arsenic in the arsenic-containing solution is changed into pentavalent arsenic through catalytic oxidation; and after oxidation, the high-stability solid arsenic minerals are obtained by synthesizing the solution by a lime arsenic precipitation process and the hydrothermal process, and the high-stability solid arsenic minerals can be directly stacked. First, calcium arsenate is obtained by the lime arsenic precipitation process, and then, the calcium arsenate is converted to the high-stability solid arsenic minerals by adopting the hydrothermal process. Toxicity extraction meets the Identification Standards for Solid Wastes and Identification Standards for Extraction Toxicity GB5085.3-2007. The technical process is short, and the arsenic precipitation effect is great. After the arsenic is precipitated, the solution can be directly discharged, and the stability of the synthesized solid arsenic minerals is high. The solid arsenic minerals can be stably stacked in a wide pH value range which is between 2 and 11 under a strong reduction condition.

Description

Technical field [0001] The invention belongs to the technical field of mineral arsenic fixation, and relates to a method for preparing high-stability arsenic fixation minerals. Background technique [0002] Arsenic is a highly toxic element with high carcinogenicity and is widely associated with various non-ferrous metal smelting process systems. In the past 30 years, with the rapid development of my country's non-ferrous metal industry, the problem of arsenic pollution has become more and more serious, seriously threatening people's lives and health. Therefore, conducting research on the treatment of arsenic pollution is an urgent and significant subject. [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 stably stored. This method has a large amount of solid waste and high cost, making it difficult to be w...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): A62D3/33A62D101/43
Inventor 刘智勇刘志宏李启厚王祖林周亚明李玉虎宋柯舟
Owner CENT SOUTH UNIV
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