Heavy metal stabilization two-step method for treatment of fly ash from urban domestic refuse burning plant

A technology for municipal solid waste and fly ash incineration, which is applied in the field of solid waste treatment and disposal, can solve the problems of complex process and other problems, and achieve the effects of favorable mixing, simple process and low operating cost

Active Publication Date: 2006-09-06
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In order to improve the effectiveness of phosphate agents, a process of phosphate stabilization after fly ash washing pretreatment has been proposed ('Monitoring the stabilization of municipal solid waste incineration fly ash byphosphation: mineralological and balance approach'Piantonea P et al. al.WasteManagement 23:225-243, 2003), but the secondary pollutants brought by washing will obviously complicate the process

Method used

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  • Heavy metal stabilization two-step method for treatment of fly ash from urban domestic refuse burning plant
  • Heavy metal stabilization two-step method for treatment of fly ash from urban domestic refuse burning plant
  • Heavy metal stabilization two-step method for treatment of fly ash from urban domestic refuse burning plant

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Please see attached figure 1 And attached figure 2 .

[0026] The pH was adjusted by sulfuric acid treatment, and then phosphate was added to stabilize heavy metals in the fly ash.

[0027] Step 1: add sulfuric acid to water in the acid solution mixing tank, the ratio of sulfuric acid to water, according to the mixed acid solution H + The molar concentration is controlled from 6M to 7M, and the sulfuric acid solution can be obtained after mixing evenly with slow stirring;

[0028] Step 2: Add fly ash to the stirring treatment tank, start stirring, and slowly add the above sulfuric acid solution into the tank at the same time, the mass ratio of the accumulatively added acid solution to fly ash is controlled to be 1:3.5; after the sulfuric acid solution and fly ash are stirred evenly , and then slowly add the stabilizing agent phosphate into the tank while stirring; the stabilizing agent should be ground and passed through a 60-mesh sieve before use, and the active in...

Embodiment 2

[0033] Please see attached figure 1 And attached image 3 .

[0034] The pH was adjusted by natural aging method, and then phosphate was added to stabilize heavy metals in the fly ash.

[0035] Step 1: Add fly ash to the pretreatment tank, start stirring, and slowly add water into the tank at the same time, the mass ratio of the accumulatively added water to fly ash is controlled to be 1:5; after the water and fly ash are stirred evenly, wet fly ash;

[0036] Step 2: Discharge the humidified fly ash from the pretreatment tank, evenly spread (thickness 0.2 to 0.3m) in the air circulation space, and age for 2 days. During this period, turn the pile once every 8 hours to obtain natural aging fly ash;

[0037] Step 3: Add natural aging fly ash into the mixing treatment tank, start stirring, and at the same time slowly stabilize the agent into the tank while stirring; the stabilizer agent should be ground and passed through a 60-mesh sieve before use, and the active ingredient o...

Embodiment 3

[0042] Please see attached figure 1 And attached Figure 4 .

[0043] The pH was adjusted by forced aging method, and then phosphate was added to stabilize heavy metals in fly ash.

[0044] Step 1: same as step 1 of embodiment 2;

[0045] Step 2: Discharge the humidified fly ash from the pretreatment tank, evenly spread (thickness 0.1 to 0.2m) in the forced aging room, and age for 8 hours to obtain the forced aging fly ash; the forced aging room is an airtight space, set The gas port introduces flue gas from the chimney of the incineration plant through the induced draft fan, flows evenly through the forced aging room, and then returns to the chimney of the incineration plant to be discharged; the volume of flue gas flowing through the forced aging room per hour is 6 to 8 times the volume of the aging room, That is, the flue gas exchange rate in the aging chamber is 6 to 8 times / hour.

[0046] Step 3: Except that the natural aging fly ash is replaced by forced aging fly as...

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Abstract

The invention relates to a method that burning and fly-ash city life waste with heavy metal stabilization which provides a chemical medicine stabilization technique. First selecting vitriol treatment, or natural aging method, or forced aging method to adjust the fly-ash pH to 9-11; then, mixing the fly-ash and the stabilizing medicine uniformly with the mass percentage in 50-80:1, to be stored for 8 hours, to complete the heavy metal chemical stabilization. The invention adds the pH adjust treatment, to reduce the soak possibility, transform the CaO into the compound with lower reaction property, to confirm the stabilization effect, and reduce the medicine cost. The invention has simple process and reliable operation.

Description

technical field [0001] The invention relates to a chemical agent stabilization technology for heavy metals in fly ash of a flue gas purification system of a municipal solid waste incineration plant, and belongs to the technical field of solid waste treatment and disposal. Background technique [0002] During the incineration process, most of the waste in domestic waste incineration plants is discharged into the atmosphere in the form of gas, part of it is left on the grate in the form of non-combustible slag, and a small amount is attached to the outer wall of the waste heat boiler or enters the waste heat boiler in the form of fly ash. The flue gas purification system is collected by the dust collector, which is called flue gas purification system fly ash (referred to as fly ash). According to my country's National Hazardous Waste List, fly ash belongs to hazardous waste and must be stabilized so that the leached concentration of heavy metals is lowe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09B3/00A62D3/00
Inventor 何品晶邵立明章骅冯军会
Owner TONGJI UNIV
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