Method for curing lake dredged sediment containing heavy metal

A technology for dredging sediment and heavy metals, which is applied in chemical instruments and methods, sludge treatment, water/sludge/sewage treatment, etc., can solve the problems of excessive heavy metal content, poor gelation and solidification effect, and poor solidification effect. High non-lateral pressure strength, short curing time, and low moisture content

Inactive Publication Date: 2013-05-08
HUBEI POLYTECHNIC UNIV
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  • Description
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AI Technical Summary

Problems solved by technology

[0005] 1. During the solidification process of the bottom mud, lime can react with the water in the bottom mud, but the generated calcium hydroxide can inhibit the cement hydration reaction, so the curing effect is poor; slag, steel slag, and silicon powder only form the skeleton It does not react with the water in the sediment, so the moisture content of the sediment is difficult to decrease, and the curing time is longer
[0006] 2. Since auxiliary materials such as lime, slag, steel slag, and silicon powder mainly play a role in skeleton construction, compared with waste gypsum and fly ash, their gelation and solidification effect is poor, so it can treat general lake sediment, and it is suitable for lake sediment containing heavy metals The solidification of solidified sediment is not applicable, and the content of heavy metals in the leachate of the solidified sediment may exceed the standard

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] The heavy metal-polluted sediment of Qingshan Lake in Huangshi City, Hubei Province was taken, with a water content of 60%. After testing, the sediment contained Pb 480mg / kg, Cu 860mg / kg, Cr 10mg / kg, Hg 0.8mg / kg, Cd 0.7mg / kg kg, As 340mg / kg, heavy metal heavy pollution sediment. First, mix cement, waste gypsum and fly ash at a mass ratio of 1:5:10 to make a curing agent, then add the curing agent to the bottom mud, and the dosage of the curing agent is 10% of the bottom mud mass; Use a sludge mixer to mix evenly to form a sludge mixture; put it into a square mold and cover it with a film, and after molding for 1 day, put it into a curing room; under the conditions of temperature 20±3°C and relative humidity 90%, curing for 2 Tianhou, the no-side compressive strength of the solidified mud block reaches 170.6KPa, which meets the requirements of solidified landfill and can be used as equal-pressure practical soil for roadbeds. After testing, the contents of Pb, Cu, Cr, Hg...

Embodiment 2

[0022] The heavy metal-polluted sediment from Cihu Lake in Huangshi City, Hubei Province was taken, with a water content of 72%. After testing, the sediment contained Pb 450mg / kg, Cu 640mg / kg, Cr 55mg / kg, Hg 1.5mg / kg, Cd 1.2mg / kg kg, As 150mg / kg, it is heavy metal polluted sediment. First, mix cement, waste gypsum and fly ash according to the mass ratio of 1:10:15 to make a curing agent, and then add the curing agent to the bottom mud. The dosage of the curing agent is 20% of the bottom mud mass; Use a sludge mixer to mix evenly to form a sludge mixture; put it into a square mold and cover it with a film, and after 3 days of molding, put it into a curing room; under the conditions of temperature 20±6°C and relative humidity 100%, cure for 10 Days later, the no-side compressive strength of the solidified mud block reached 190.6KPa, meeting the requirements of solidified landfill, and can be used as equal-pressure practical soil for roadbeds. After testing, the contents of Pb, ...

Embodiment 3

[0024] The heavy metal-polluted sediment from Cihu Lake in Huangshi City, Hubei Province was taken, with a water content of 67%; after testing, the sediment contained Pb 850mg / kg, Cu 1100mg / kg, Cr 74mg / kg, Hg 1.0mg / kg, Cd 3.2mg / kg kg, As 200mg / L, heavy metal heavy pollution sediment. First, mix cement, waste gypsum and fly ash according to the mass ratio of 1:0.5:1 to make a curing agent, and then add the curing agent to the bottom mud. The dosage of the curing agent is 3% of the bottom mud mass; Use a sludge mixer to mix evenly to form a sludge mixture; put it into a square mold and cover it with a film, and after 2 days of molding, put it into a curing room; under the conditions of temperature 20±4°C and relative humidity 70%, cure for 6 Days later, the no-side compressive strength of the solidified mud block reached 97.5KPa, meeting the requirements of solidified landfill, and can be used as equal-pressure practical soil for roadbeds. After testing, the contents of Pb, Cu,...

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PUM

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Abstract

The invention belongs to a treatment method of solid waste in environmental engineering, and particularly relates to a method for curing lake dredged sediment containing heavy metal. The method is characterized by comprising the steps of adding a curing agent prepared from waste gypsum, coal ash and cement in a mixing manner to lake dredged sediment containing heavy metal, evenly stirring, and covering a plastic film on the surface for molding for 1-3 days; and maintaining for 2-10 days under the conditions that the temperature is 20+/-(3-6) DEG C and the relative humidity is 70-100% to obtain a solidified clod of which the unconfined compression strength is greater than or equal to 170.6kpa, wherein the weight ratio of the waste gypsum to the coal ash to the cement is 1 to (0.5-10) to (1-15); and the adding amount of the curing agent is 3-20% of mass of the lake dredged sediment containing the heavy metal. Industrial wastes such as the coal ash, the waste gypsum and the like are taken as curing agent materials of heavy metal polluted sediment; and resource utilization of the wastes such as the polluted sediment, the coal ash and the waste gypsum is achieved, so as to achieve the target of treatment of wastes with processes of wastes against one another.

Description

technical field [0001] The invention belongs to a treatment method for solid waste in environmental engineering, in particular to a method for solidifying dredged bottom mud of lakes containing heavy metals. Background technique [0002] At present, polluted sediment has become a potential internal source load of lakes, and the migration of pollutants (heavy metals) in sediment seriously affects the water quality of lakes. Sediment dredging technology can restore the normal function of water bodies by dredging and dredging seriously polluted lakes and river sections; it is a direct and effective treatment method that can permanently eliminate the impact of polluted sediment on lake water quality . [0003] However, the safe disposal of dredged contaminated sediment has always been a technical problem. The conventional disposal methods of dredged sediment mainly include stacking, backfilling of depressions, creation of land, land improvement, utilization of building materia...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B28/04C04B28/14C02F11/00C02F101/20
Inventor 肖文胜陶敏马敏殷斌张家泉刘婷白翠萍吕继良
Owner HUBEI POLYTECHNIC UNIV
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