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Passivation treatment method for arsenic-containing sludge

A disposal method and sludge technology, applied in sludge treatment, chemical instruments and methods, fixed/solidified sludge treatment, etc., can solve problems such as unit and treatment capacity not meeting requirements, high risk and toxicity, etc., and achieve applicability Strong, reduced leaching concentration, and short disposal cycle

Inactive Publication Date: 2020-01-17
云南大地丰源环保有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

According to incomplete statistics, the amount of various arsenic-containing waste residues produced in the smelting process alone should be more than 2 million tons per year. Because of its high risk and toxicity, it is a hazardous waste (National Hazardous Waste List No. HW24) and must be safely treated before being released. The final disposal, but the units with qualifications and processing capacity for arsenic-containing waste residue treatment are far from meeting the requirements. The treatment methods are limited to anti-seepage deep burial and cement solidification. The commonly used solidification treatment technologies are cement solidification, asphalt solidification and pyrolysis. law curing

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Taking arsenic-containing sludge from a smelter as the treatment object, the original leaching results: pH=4.25, total As=1.36×104mg / L.

[0023] Utilize the method of the present invention to process this arsenic-containing sludge:

[0024] Stir the arsenic-containing sludge and water at a solid-to-liquid ratio of 1:0.7 to make a slurry, add solid lime to adjust the pH of the slurry to 7.0, and then add a mixed stabilizer according to 20% of the sludge amount, and the stabilizer preparation ratio (mass Ratio) is ferric chloride: polyferric: magnesium chloride: calcium dihydrogen phosphate is equal to 4:2:1:3, stirring and reacting for 20 minutes; then adding cement to solidify according to 25% of the total weight of the sludge, and curing the solidified body for 7 days .

[0025] The leaching results of solidified body: pH=8.52, total As=1.25mg / L, arsenic removal rate is 99.91%.

Embodiment 2

[0027] Taking arsenic-containing sludge from a fertilizer factory as the treatment object, the original leaching results: pH<1, total As=93.3mg / L.

[0028] Utilize the method of the present invention to process this arsenic-containing sludge:

[0029] Stir the arsenic-containing sludge and water at a solid-to-liquid ratio of 1:0.8 to make a slurry, add caustic soda to adjust the pH of the slurry to 5.5, and then add a mixed stabilizer according to 8% of the sludge amount, and the stabilizer preparation ratio (mass Ratio) is polyiron: magnesium chloride: calcium dihydrogen phosphate is equal to 4:3:3, stirring reaction for 15 minutes; then add asphalt according to 20% of the total weight of sludge to solidify, and the solidified body is cured for 3 days.

[0030] The leaching results of solidified body: pH=7.35, total As=0.28mg / L, arsenic removal rate is 99.70%.

Embodiment 3

[0032] Taking arsenic-containing sludge from a chemical plant as the treatment object, the original leaching results: pH=7.42, total As=744mg / L.

[0033] Utilize the method of the present invention to process this arsenic-containing sludge:

[0034] The arsenic-containing sludge and water are stirred at a solid-to-liquid ratio of 1:0.6 to prepare a slurry, and a mixed stabilizer is added according to 20% of the sludge volume. The stabilizer preparation ratio (mass ratio) is ferric chloride: polyferric: Magnesium chloride is equal to 4:3:3, and the reaction is stirred for 20 minutes; then 30% of the total weight of the sludge is added with a mixed curing agent for curing, cement: asphalt is equal to 7:3, and the solidified body is cured for 7 days.

[0035] The leaching results of solidified body: pH=7.68, total As=0.11mg / L, arsenic removal rate is 99.98%.

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Abstract

A passivation treatment method for arsenic-containing sludge comprises the following steps of: (1) adding water to the arsenic-containing sludge and stirring to form slurry; (2) adjusting the pH of the slurry with an inorganic acid or alkali; (3) adding a stabilizer under stirring; and (4) adding a curing agent, stirring uniformly and curing. Arsenide in the arsenic-containing sludge is passivatedby using mixed stabilizers of iron salt, magnesium salt and phosphate to degrade toxicity, and a series of complex reactions occur through chelation and encapsulation of the curing agent to generatestable solidified bodies after curing, thus achieving the purpose of harmless treatment of the arsenic-containing sludge. The process is operated at normal temperature and pressure, has strong applicability, can effectively reduce the leaching concentration of arsenide, and the treated arsenic-containing sludge meets the landfill requirements of hazardous wastes, and the passivation treatment method has small capacity expansion, short disposal period and low energy consumption.

Description

technical field [0001] The invention belongs to the technical field of harmless treatment of hazardous waste, and in particular relates to a treatment method for arsenic-containing sludge. Background technique [0002] World Health Organization officials announced that at least 50 million people around the world are facing the threat of endemic arsenic poisoning, most of them are Asian countries, and China is one of the countries most seriously affected by arsenic poisoning. From Hunan, Yunnan, Guangxi, Guizhou, Shanxi, and Inner Mongolia, where the traditional arsenic damage is serious, it has spread rapidly to the whole country, causing bad social impact. [0003] Arsenic is a sulfur-friendly metalloid element. It mainly exists in the form of sulfide, sulfur arsenide, and arsenate in natural minerals, and is mainly associated with non-ferrous metals such as lead, zinc, copper, and tin, accounting for about 10% of the total arsenic ore. More than 80% of the reserves, so th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F11/00C02F11/143C02F101/10C02F101/20
CPCC02F11/008C02F2101/103C02F2101/20C02F11/143
Inventor 任雪娇尹砾珩李晨曦
Owner 云南大地丰源环保有限公司